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SpaceX is privately funding the development of orbital launch systems that can be
reused Reuse is the action or practice of using an item, whether for its original purpose (conventional reuse) or to fulfill a different function ( creative reuse or repurposing). It should be distinguished from recycling, which is the breaking down of ...
many times, in a manner similar to the reusability of
aircraft An aircraft is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or by using the Lift (force), dynamic lift of an airfoil, or in ...
.
SpaceX Space Exploration Technologies Corp. (SpaceX) is an American spacecraft manufacturer, launcher, and a satellite communications corporation headquartered in Hawthorne, California. It was founded in 2002 by Elon Musk with the stated goal o ...
has been developing the technologies over several years to facilitate full and rapid reusability of space
launch vehicle A launch vehicle or carrier rocket is a rocket designed to carry a payload ( spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pads, supported by a launch control center and sys ...
s. The project's long-term objectives include returning a launch vehicle first stage to the launch site in minutes and to return a second stage to the
launch pad A launch pad is an above-ground facility from which a rocket-powered missile or space vehicle is vertically launched. The term ''launch pad'' can be used to describe just the central launch platform ( mobile launcher platform), or the entir ...
following orbital realignment with the launch site and
atmospheric reentry Atmospheric entry is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. There are two main types of atmospheric entry: ''uncontrolled entry'', such as the ...
in up to 24 hours. SpaceX's long term goal is that both stages of their orbital launch vehicle will be designed to allow reuse a few hours after return. The program was publicly announced in 2011. SpaceX first achieved a successful landing and recovery of a first stage in December 2015. The first re-flight of a landed first stage occurred in March 2017 with the second occurring in June 2017, that one only five months after the maiden flight of the booster. The third attempt occurred in October 2017 with the
SES-11 SES-11 / EchoStar 105 is a geostationary communications satellite operated by SES S.A. and EchoStar and designed and manufactured by Airbus Defence and Space. It has a mass of and has a design life of at least 15 years. The spacecraft had bee ...
/ EchoStar-105 mission. Reflights of refurbished first stages then became routine. In May 2021, B1051 became the first booster to power ten missions. The
reusable launch system A reusable launch vehicle have parts that can be recovered and reflown, while carrying payloads from the surface to outer space. Rocket stages are the most common launch vehicle parts aimed for reuse. Smaller parts such as rocket engines and boos ...
technology was developed and initially used for the first stage of
Falcon 9 Falcon 9 is a partially reusable medium lift launch vehicle that can carry cargo and crew into Earth orbit, produced by American aerospace company SpaceX. The rocket has two stages. The first (booster) stage carries the second stage and pay ...
. After stage separation, the booster flips around, an optional boostback burn is done to reverse its course, a reentry burn, controlling direction to arrive at the landing site and a landing burn to affect the final low-altitude deceleration and touchdown. SpaceX intended (from at least 2014) to develop technology to extend reusable flight hardware to second stages, a more challenging engineering problem because the vehicle is travelling at orbital velocity. Second stage reuse is considered paramount to Elon Musk's plans to enable the settlement of Mars. Initial concepts to make the second stage of Falcon 9 reusable have been abandoned. , SpaceX is actively developing the
Starship A starship, starcraft, or interstellar spacecraft is a theoretical spacecraft designed for traveling between planetary systems. The term is mostly found in science fiction. Reference to a "star-ship" appears as early as 1882 in '' Oahspe: A Ne ...
system, with the intent to make it a fully-reusable two-stage launch vehicle, intended to replace all of its existing launch vehicles and spacecraft used for satellite delivery and human transport—Falcon 9, Falcon Heavy and Dragon—and also eventually support flights to the Moon and Mars. In addition it could be used for point-to-point transportation on Earth.


History

SpaceX initially attempted to land the first stage of the Falcon 1 by parachute, but the stage did not survive re-entry into the atmosphere. They continued to experiment unsuccessfully with parachutes on the earliest
Falcon 9 Falcon 9 is a partially reusable medium lift launch vehicle that can carry cargo and crew into Earth orbit, produced by American aerospace company SpaceX. The rocket has two stages. The first (booster) stage carries the second stage and pay ...
flights after 2010. SpaceX subsequently switched its focus to developing a powered descent
landing Landing is the last part of a flight, where a flying animal, aircraft, or spacecraft returns to the ground. When the flying object returns to water, the process is called alighting, although it is commonly called "landing", "touchdown" or ...
system. The broad outline of the reusable launch system was first publicly described in September 2011. SpaceX said it would attempt to develop powered descent and recovery of both Falcon 9 stagesa fully vertical takeoff, vertical landing (
VTVL Vertical takeoff, vertical landing (VTVL) is a form of takeoff and landing for rockets. Multiple VTVL craft have flown. The most widely known and commercially successful VTVL rocket is SpaceX's Falcon 9 first stage. VTVL technologies were dev ...
) rocket. The company produced a computer-animated video depicting a notional view of the first stage returning tail-first for a powered descent and the second stage with a heat shield, reentering head first before rotating for a powered descent. In September 2012, SpaceX began flight tests on a prototype reusable first stage with the suborbital Grasshopper rocket. Those tests continued into 2014, including testing of a second and larger prototype vehicle,
F9R Dev1 Falcon 9 prototypes were experimental flight test reusable rockets that performed vertical takeoffs and landings. The project was privately funded by SpaceX, with no funds provided by any government until later on. Two prototypes were built, ...
. News of the Grasshopper test rocket had become public a few days earlier, when the
US Federal Aviation Administration The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic m ...
released a draft Environmental Impact Assessment for the SpaceX Test Site in Texas, and the space media had reported it. In May 2012, SpaceX obtained a set of atmospheric test data for the recovery of the Falcon 9 first stage based on 176 test runs in the
NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeedin ...
Marshall Space Flight Center The George C. Marshall Space Flight Center (MSFC), located in Redstone Arsenal, Alabama (Huntsville postal address), is the U.S. government's civilian rocketry and spacecraft propulsion research center. As the largest NASA center, MSFC's firs ...
wind tunnel Wind tunnels are large tubes with air blowing through them which are used to replicate the interaction between air and an object flying through the air or moving along the ground. Researchers use wind tunnels to learn more about how an aircraft ...
test facility. The work was contracted for by SpaceX under a reimbursable
Space Act Agreement Space Act Agreements (abbreviated SAA) are a type of legal agreement specified in the National Aeronautics and Space Act of 1958 (and subsequent congressional authorizations) that uniquely empowers the National Aeronautics and Space Administration ...
with NASA. In 2012, it was projected that the first-stage separation of a reusable Falcon 9 rocket would occur at a velocity of approximately rather than for an expendable Falcon 9, to provide the residual fuel necessary for the deceleration and turnaround maneuver and the controlled descent and landing. In November 2012, CEO
Elon Musk Elon Reeve Musk ( ; born June 28, 1971) is a business magnate and investor. He is the founder, CEO and chief engineer of SpaceX; angel investor, CEO and product architect of Tesla, Inc.; owner and CEO of Twitter, Inc.; founder of The B ...
announced SpaceX's plans to build a second, much larger, reusable rocket system, this one to be powered by LOX/
methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane ...
rather than LOX/
RP-1 RP-1 (alternatively, Rocket Propellant-1 or Refined Petroleum-1) is a highly refined form of kerosene outwardly similar to jet fuel, used as rocket fuel. RP-1 provides a lower specific impulse than liquid hydrogen (LH2), but is cheaper, is s ...
used on Falcon 9 and Falcon Heavy. The new system was to be "an evolution of SpaceX's Falcon 9 booster", and SpaceX reiterated their commitment to develop a breakthrough in vertical landing technology. By the end of 2012, the demonstration test vehicle, Grasshopper, had made three VTVL test flightsincluding a 29-second hover flight to on December 17, 2012. In early March 2013, SpaceX successfully tested Grasshopper for a fourth time when it flew to an altitude of over . In March 2013, SpaceX announced that it would instrument and equip subsequent Falcon 9 first-stages as controlled descent test vehicles, with plans for over-water propulsively decelerated simulated landings beginning in 2013, with the intent to return the vehicle to the launch site for a powered landingpossibly as early as mid-2014. The April 2013 draft Environmental Impact Statement for the proposed
SpaceX South Texas Launch Site Starbase is a spaceport, production, and development facility for Starship rockets, located at Boca Chica, Texas, United States. It is in construction in the late 2010s and 2020s by SpaceX, an American aerospace manufacturer. When conceptuali ...
includes specific accommodations for return of the Falcon 9 first-stage boosters to the launch site. Elon Musk first publicly referred to the reusable Falcon 9 as the Falcon 9-R in April 2013. In September 2013, SpaceX successfully relit three engines of a spent booster on an orbital launch, and the booster re-entered the atmosphere at hypersonic speed without burning up. With the data collected from the first flight test of a booster-controlled descent from high altitude, coupled with the technological advancements made on the Grasshopper low-altitude landing demonstrator, SpaceX announced it believed it was ready to test a full land-recovery of a booster stage. Based on the positive results from the first high-altitude flight test, SpaceX advanced the expected date of a test from mid-2014 to early 2015, with the intention of doing so on the next Space Station cargo resupply flight pending regulatory approvals. That flight took place on April 18, 2014. Musk stated in May 2013 that the goal of the program is to achieve full and rapid reusability of the first stage by 2015, and to develop full launch vehicle reusability following that as "part of a future design architecture". In September 2013, SpaceX said that if all aspects of the test program were successful and if a customer is interested, the first reflight of a Falcon 9 booster stage could happen as early as late 2014. In February 2014, SpaceX made explicit that the newly defined super-heavy launch vehicle for what was then called
Mars Colonial Transporter SpaceX Starship development began in 2012, when Elon Musk, CEO of American aerospace company SpaceX, first publicly described a high-level plan to build a reusable rocket system with substantially greater capabilities than the Falcon 9 and the ...
would also make use of the reusable technology. This was consistent with Musk's strategic statement in 2012 that "The revolutionary breakthrough will come with rockets that are fully and rapidly reusable. We will never conquer
Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin at ...
unless we do that. It'll be too expensive. The American colonies would never have been pioneered if the ships that crossed the ocean hadn't been reusable." Also in May 2014, SpaceX publicly announced an extensive test program for a related reusable technology: a propulsively landed
space capsule A space capsule is an often-crewed spacecraft that uses a blunt-body reentry capsule to reenter the Earth's atmosphere without wings. Capsules are distinguished from other satellites primarily by the ability to survive reentry and return a payl ...
called ''
DragonFly A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat thre ...
''. The tests were to be run in Texas at the McGregor Rocket Test Facility in 2014–2015. In June 2014, COO
Gwynne Shotwell Gwynne Shotwell ( Rowley; born November 23, 1963) is an American businesswoman and engineer. She is the president and chief operating officer of SpaceX, an American space transportation company, where she is responsible for day-to-day operation ...
clarified that all funding for
development Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking, development phase, including finance and budgeting *Development (music), the process thematic material is reshaped * Photograph ...
and
testing An examination (exam or evaluation) or test is an educational assessment intended to measure a test-taker's knowledge, skill, aptitude, physical fitness, or classification in many other topics (e.g., beliefs). A test may be administered verba ...
of the reusable launch system technology development program is private funding from SpaceX, with no contribution by the
US government The federal government of the United States (U.S. federal government or U.S. government) is the national government of the United States, a federal republic located primarily in North America, composed of 50 states, a city within a feder ...
. As of 2017 SpaceX had spent over a billion dollars on the development program. For the first time, SpaceX stated in July 2014 that they are "highly confident of being able to land successfully on a floating launch pad or back at the launch site and refly the rocket with no required refurbishment." By late 2014, SpaceX suspended or abandoned the plan to recover and reuse the Falcon 9 second stage; the additional mass of the required heat shield, landing gear, and low-powered landing engines would incur too great a performance penalty. While the idea was mentioned again later it was ultimately abandoned as
Starship A starship, starcraft, or interstellar spacecraft is a theoretical spacecraft designed for traveling between planetary systems. The term is mostly found in science fiction. Reference to a "star-ship" appears as early as 1882 in '' Oahspe: A Ne ...
development made progress. In December 2015, following the recovery of the first stage from December 22 launch, SpaceX projected that the first reflight of a recovered booster would likely occur in 2016, but that their plan was to not refly the December 22 recovered stage for that purpose. In September 2016, SpaceX announced that development was underway to extend the reusable flight hardware to second stages, a more challenging engineering problem because the vehicle is travelling at orbital velocity. The reusable technology was to have been extended to the 2016 designs of both the tanker and crewed spaceship upper stage variants as well as the first stage of the
Interplanetary Transport System SpaceX Starship development began in 2012, when Elon Musk, CEO of American aerospace company SpaceX, first publicly described a high-level plan to build a reusable rocket system with substantially greater capabilities than the Falcon 9 and the ...
, and is considered paramount to the plans Elon Musk is championing to enable the settlement of Mars. In 2016, initial test flights of an Interplanetary Transport System vehicle were expected no earlier than 2020. In 2017 SpaceX was making test flight progress in incrementally and iteratively developing a fairing recovery system. In July 2017, Musk said "we are quite close to being able to recover the fairing. ... We've got a decent shot of recovering a fairing by the end of the year, and reflight by late this year or early next." The
cost In production, research, retail, and accounting, a cost is the value of money that has been used up to produce something or deliver a service, and hence is not available for use anymore. In business, the cost may be one of acquisition, in whic ...
savings to SpaceX of recovering the fairing is expected to be on the order of . Together, the booster stage and the fairing make up approximately 80 percent of the cost of a launch. The fairings are equipped with a steerable parachute and fall towards a ship equipped with a big net. Intact fairings could be recovered from the ocean starting in 2017, with landings in the net from 2019 on.


Technologies

Several new technologies needed to be developed and tested to facilitate successful launch and recovery of the first stages of Falcon 9 and Falcon Heavy, and both stages of
Starship A starship, starcraft, or interstellar spacecraft is a theoretical spacecraft designed for traveling between planetary systems. The term is mostly found in science fiction. Reference to a "star-ship" appears as early as 1882 in '' Oahspe: A Ne ...
. Since 2017, recovery and reuse of Falcon rocket boosters has become routine. The technologies that were developed for Falcon 9, some of which are still being refined, include: * Restartable
ignition system An ignition system generates a spark or heats an electrode to a high temperature to ignite a fuel-air mixture in spark ignition internal combustion engines, oil-fired and gas-fired boilers, rocket engines, etc. The widest application for spark i ...
for the first-stage booster. Restarts are required at both supersonic velocities in the upper atmosphere—in order to reverse the high velocity away from the launch pad and put the booster on a descent trajectory back toward the launch pad—and at high
transonic Transonic (or transsonic) flow is air flowing around an object at a speed that generates regions of both subsonic and supersonic airflow around that object. The exact range of speeds depends on the object's critical Mach number, but transoni ...
velocities in the lower atmosphere—in order to slow the terminal descent and to perform a soft landing. If the booster returns to a landing site on land another burn is needed shortly after stage separation to reverse the flight direction of the booster, for a total of four burns for the center engine. * New
attitude control Attitude control is the process of controlling the orientation of an aerospace vehicle with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc. Controlling vehicle ...
technology for the booster to bring the descending rocket body through the atmosphere in a manner conducive both to non-destructive return and sufficient aerodynamic control such that the terminal phase of the
landing Landing is the last part of a flight, where a flying animal, aircraft, or spacecraft returns to the ground. When the flying object returns to water, the process is called alighting, although it is commonly called "landing", "touchdown" or ...
is possible. This includes sufficient roll control authority to keep the rocket from spinning excessively as occurred on the first high-altitude flight test in September 2013, where the roll rate exceeded the capabilities of the booster
attitude control system Spacecraft attitude control is the process of controlling the orientation of a spacecraft (vehicle/satellite) with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, et ...
(ACS) and the fuel in the tanks "centrifuged" to the side of the tank shutting down the single engine involved in the low-altitude deceleration maneuver. The technology needs to handle the transition from the vacuum of space at
hypersonic In aerodynamics, a hypersonic speed is one that exceeds 5 times the speed of sound, often stated as starting at speeds of Mach 5 and above. The precise Mach number at which a craft can be said to be flying at hypersonic speed varies, since ind ...
conditions, decelerating to
supersonic Supersonic speed is the speed of an object that exceeds the speed of sound ( Mach 1). For objects traveling in dry air of a temperature of 20 °C (68 °F) at sea level, this speed is approximately . Speeds greater than five times ...
velocities and passing through
transonic Transonic (or transsonic) flow is air flowing around an object at a speed that generates regions of both subsonic and supersonic airflow around that object. The exact range of speeds depends on the object's critical Mach number, but transoni ...
buffet A buffet can be either a sideboard (a flat-topped piece of furniture with cupboards and drawers, used for storing crockery, glasses, and table linen) or a system of serving meals in which food is placed in a public area where the diners serve ...
, before relighting one of the main-stage engines at
terminal velocity Terminal velocity is the maximum velocity (speed) attainable by an object as it falls through a fluid ( air is the most common example). It occurs when the sum of the drag force (''Fd'') and the buoyancy is equal to the downward force of grav ...
. * Hypersonic
grid fin Grid fins (or lattice fins) are a type of flight control surface used on rockets and bombs, sometimes in place of more conventional control surfaces, such as planar fins. They were developed in the 1950s by a team led by and used since the 1970 ...
s were added to the booster test vehicle design beginning on the fifth ocean controlled-descent test flight in 2014 in order to enable precision landing. Arranged in an "X" configuration, the grid fins control the descending rocket's
lift vector A fluid flowing around an object exerts a force on it. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the force parallel to the flow directi ...
once the vehicle has returned to the atmosphere to enable a much more precise landing location. Iteration on the design continued into 2017. Larger and more robust grid fins, made from forged
titanium Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion i ...
and left unpainted, were first tested in June 2017, and have been used on all reusable Block 5 Falcon 9 first stages since May 2018. * The rocket engine needs to be throttleable to achieve zero velocity at the same time the rocket reaches the ground. Even the lowest possible thrust of a single
Merlin 1D Merlin is a family of rocket engines developed by SpaceX for use on its Falcon 1, Falcon 9 and Falcon Heavy launch vehicles. Merlin engines use RP-1 and liquid oxygen as rocket propellants in a gas-generator power cycle. The Merlin eng ...
engine exceeds the weight of the nearly empty Falcon 9 booster core, therefore the rocket cannot hover. *
Terminal guidance In the field of weaponry, terminal guidance refers to any guidance system that is primarily or solely active during the "terminal phase", just before the weapon impacts its target. The term is generally used in reference to missile guidance system ...
and landing capability, including a vehicle control system and a control system software algorithm to be able to land a rocket with the thrust-to-weight ratio of the vehicle greater than one, with closed-loop thrust vector and throttle control *
Navigation Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navigation ...
sensor suite for precision landing * A large
floating landing platform A floating launch vehicle operations platform is a marine vessel used for launch or landing operations of an orbital launch vehicle by a launch service provider: putting satellites into orbit around Earth or another celestial body, or recovering ...
for launches where the first stage does not have sufficient fuel to return to the launch site. As of 2022, SpaceX built three
autonomous spaceport drone ship An autonomous spaceport drone ship (ASDS) is an ocean-going vessel derived from a deck barge, outfitted with station-keeping engines and a large landing platform and is autonomously controlled when on station for a landing. Construction of ...
s, one operating the West coast and two on the East coast of the United States. * A
thermal protection system Atmospheric entry is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. There are two main types of atmospheric entry: ''uncontrolled entry'', such as the entr ...
to avoid damage to the first stage when re-entering the atmosphere. * Lightweight, deployable
landing gear Landing gear is the undercarriage of an aircraft or spacecraft that is used for takeoff or landing. For aircraft it is generally needed for both. It was also formerly called ''alighting gear'' by some manufacturers, such as the Glenn L. Mart ...
for the booster stage. In May 2013, the design was shown to be a nested, telescoping piston on an A-frame. The total span of the four
carbon fiber Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...
/
aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It ha ...
extensible landing legs is approximately , and weigh less than . Deployment system uses high-pressure
Helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic ta ...
as the
working fluid For fluid power, a working fluid is a gas or liquid that primarily transfers force, motion, or mechanical energy. In hydraulics, water or hydraulic fluid transfers force between hydraulic components such as hydraulic pumps, hydraulic cylinders, a ...
. With
Flight 25 Flight or flying is the process by which an object moves through a space without contacting any planetary surface, either within an atmosphere (i.e. air flight or aviation) or through the vacuum of outer space (i.e. spaceflight). This can be a ...
it was announced that each landing leg contained a "crush core", to absorb the impact of landing for particularly hard landings.


Economics of rocket reuse

In order to make the Falcon 9 reusable and return to the launch site, extra
propellant A propellant (or propellent) is a mass that is expelled or expanded in such a way as to create a thrust or other motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicles, the ...
and
landing gear Landing gear is the undercarriage of an aircraft or spacecraft that is used for takeoff or landing. For aircraft it is generally needed for both. It was also formerly called ''alighting gear'' by some manufacturers, such as the Glenn L. Mart ...
must be carried on the first stage, requiring around a 30 percent reduction of the maximum payload to orbit in comparison with the expendable Falcon 9. Reflight of a previously used stage on a subsequent flight is dependent on the condition of the landed stage, and is a technique that has seen little use outside of the
Space Shuttle The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program n ...
's reusable
solid rocket boosters A solid rocket booster (SRB) is a large solid propellant motor used to provide thrust in spacecraft launches from initial launch through the first ascent. Many launch vehicles, including the Atlas V, SLS and space shuttle, have used SRBs to giv ...
. Musk projected in 2015 that the reflight step of the program would be "straightforward," because of the multiple full duration firings of the engines that had been done on the ground, and the multiple engine restarts that had been demonstrated by that time, with no significant degradation seen. In 2015, industry analysts continued to forecast problems that could prevent economic reuse because costs to refurbish and relaunch the stage were not yet demonstrated, and the economic case for reuse would necessarily be highly dependent on launching frequently. SpaceX is expected to significantly reduce the cost of access to space, and change the increasingly competitive market in space launch services. Michael Belfiore wrote in ''
Foreign Policy A state's foreign policy or external policy (as opposed to internal or domestic policy) is its objectives and activities in relation to its interactions with other states, unions, and other political entities, whether bilaterally or through ...
'' in 2013 that, at a published cost of per launch to
low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never m ...
, "Falcon 9 rockets are already the cheapest in the industry. Reusable Falcon 9s could drop the price by an
order of magnitude An order of magnitude is an approximation of the logarithm of a value relative to some contextually understood reference value, usually 10, interpreted as the base of the logarithm and the representative of values of magnitude one. Logarithmic di ...
, sparking more space-based enterprise, which in turn would drop the cost of access to space still further through economies of scale." Even for military launches, which have a number of contractual requirements for additional launch services to be provided, SpaceX's price is under . Space industry analyst Ajay Kothari has noted that SpaceX reusable technology could do for
space transport Spaceflight (or space flight) is an application of astronautics to fly spacecraft into or through outer space, either with or without humans on board. Most spaceflight is uncrewed and conducted mainly with spacecraft such as satellites in o ...
"what jet engines did for air transportation sixty years ago when people never imagined that more than 500 million passengers would travel by airplanes every year and that the cost could be reduced to the level it is—all because of passenger volume and reliable reusability." SpaceX said in January 2014 that if they are successful in developing the reusable technology, launch prices of around for a reusable Falcon 9 were possible, and following the successful first stage recovery in December 2015, Musk said that "the potential cost reduction over the long term is probably in excess of a factor of 100." launch service providers who
compete Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, indivi ...
with SpaceX were not planning to develop similar technology or offer competing reusable launcher options. Neither ILS, which markets launches of the Russian
Proton rocket Proton (Russian: Протон) (formal designation: UR-500) is an expendable launch system used for both commercial and Russian government space launches. The first Proton rocket was launched in 1965. Modern versions of the launch system are sti ...
;
Arianespace Arianespace SA is a French company founded in 1980 as the world's first commercial launch service provider. It undertakes the operation and marketing of the Ariane programme. The company offers a number of different launch vehicles: the heavy ...
; nor
SeaLaunch Sea Launch was a multinational—Norway, Russia, Ukraine, United States—spacecraft launch company founded in 1995 that provided orbital launch services from 1999–2014. The company used a mobile maritime launch platform for equatorial lau ...
were planning on developing and marketing reusable launch vehicle services. SpaceX was the only competitor that projected a sufficiently
elastic Elastic is a word often used to describe or identify certain types of elastomer, elastic used in garments or stretchable fabrics. Elastic may also refer to: Alternative name * Rubber band, ring-shaped band of rubber used to hold objects togethe ...
market on the demand side to justify the costly development of reusable rocket technology and the expenditure of
private capital In economics, capital goods or capital are "those durable produced goods that are in turn used as productive inputs for further production" of goods and services. At the macroeconomic level, "the nation's capital stock includes buildings, eq ...
to develop options for that theoretical market opportunity. In 2014 the Falcon 9 v1.1 rocket was designed with about 30 percent more capacity than its official payload specifications; the additional performance was reserved for SpaceX to perform first-stage re-entry and landing tests towards reusability while still achieving the specified orbital payload delivery for customers. In order to achieve the full economic benefit of the reusable technology, it is necessary that the reuse be both rapid and complete—without the long and costly refurbishment period or partially reusable design that plagued earlier attempts at reusable launch vehicles. SpaceX has been explicit that the "huge potential to open up space flight" is dependent on achieving both complete and rapid reusability. CEO Musk stated in 2014 that success with the technology development effort could reduce "the cost of spaceflight by a factor of 100" because the cost of the propellant/oxidizer on the Falcon 9 is only 0.3 percent of the total cost of the vehicle. Separate from the
market competition In economics, competition is a scenario where different Economic agent, economic firmsThis article follows the general economic convention of referring to all actors as firms; examples in include individuals and brands or divisions within the sa ...
brought about by SpaceX lower launch prices and the potential future of even more radically lower launch prices if the technology can be completed successfully, ''
Aviation Week ''Aviation Week & Space Technology'', often abbreviated ''Aviation Week'' or ''AW&ST'', is the flagship magazine of the Aviation Week Network. The weekly magazine is available in print and online, reporting on the aerospace, defense and aviatio ...
'' said in 2014 that "SpaceX reusable launch work is an R&D model"—"The audacity of the concept and speed of the program’s progress make it an exemplar. ... hebreakneck pace of development has been almost
Apollo Apollo, grc, Ἀπόλλωνος, Apóllōnos, label=genitive , ; , grc-dor, Ἀπέλλων, Apéllōn, ; grc, Ἀπείλων, Apeílōn, label=Arcadocypriot Greek, ; grc-aeo, Ἄπλουν, Áploun, la, Apollō, la, Apollinis, label= ...
-like in its execution... ven whilesuccess is far from guaranteed." On March 9, 2016, SpaceX President Gwynne Shotwell gave a more realistic appraisal of the potential savings of a reused launch now that attempts to reuse the second stage had been abandoned due to cost and weight issues. She said at cost of refueling and cost of refurbishing a used first stage could potentially allow a launch to be priced as low as , a 30% saving. SpaceX's biggest customer SES said it wants to be the first to ride a reused vehicle, though it wants a launch price of or a 50% saving to offset the risk of pioneering the process. According to Elon Musk, almost every piece of the Falcon should be reused over 100 times. Heat shields and a few other items should be reused over 10 times before replacement. In March 2017, SpaceX announced progress in their experiments to recover, and eventually reuse, the 6-million dollar
payload fairing A payload fairing is a nose cone used to protect a spacecraft payload against the impact of dynamic pressure and aerodynamic heating during launch through an atmosphere. An additional function on some flights is to maintain the cleanroom envi ...
. On the SES-10 mission, one of the fairing halves performed a controlled atmospheric reentry and
splashdown Splashdown is the method of landing a spacecraft by parachute in a body of water. It was used by crewed American space capsules prior to the Space Shuttle program, by SpaceX Dragon and Dragon 2 capsules and by NASA's Orion Multipurpose Crew ...
using thrusters and a steerable parachute; fairings are eventually slated to land on a floating "bouncy castle" structure. SpaceX began re-flight of previously launched booster stages in 2017. The first re-flight was accomplished in March 2017, nearly a year after the booster's
maiden flight The maiden flight, also known as first flight, of an aircraft is the first occasion on which it leaves the ground under its own power. The same term is also used for the first launch of rockets. The maiden flight of a new aircraft type is alw ...
; the second was in June 2017, only five months after its maiden flight. Both were successful, and both
insurer Insurance is a means of protection from financial loss in which, in exchange for a fee, a party agrees to compensate another party in the event of a certain loss, damage, or injury. It is a form of risk management, primarily used to hedge ...
s and launch service customers are readily supporting the newly emerging market in launch services provided by multiple-use boosters. In August 2020, Elon Musk tweeted that refurbishment and reuse of a booster is done for less than 10% the price of a new booster while the payload reduction is below 40%. According to his tweet, SpaceX breaks even with a second flight per booster and saves money from the third flight on. At that time, Falcon 9 Block 5 had made 35 flights with 11 boosters.


Technical feasibility

Prior to the reusability program's success in December 2015, the
return Return may refer to: In business, economics, and finance * Return on investment (ROI), the financial gain after an expense. * Rate of return, the financial term for the profit or loss derived from an investment * Tax return, a blank document or t ...
of an orbital launch system booster rocket had never been accomplished, and many questioned both technical and economic feasibility. And even after this success, the ''rapid'' reuse of a rocket has not been attempted. Developing a reusable rocket is extremely challenging due to the small percentage of a rocket's mass that can make it to orbit. Typically, a rocket's payload is only about 3% of the mass of the rocket which is also roughly the amount of mass in fuel that is required for the vehicle's re-entry. Elon Musk said at the beginning of the program that he believed the return, vertical landing and recovery was possible because the SpaceX manufacturing methodologies result in a rocket efficiency exceeding the typical 3% margin. A SpaceX rocket operating in the reusable configuration has approximately 30% less payload lift capacity than the same rocket in an expendable configuration. Although the
reusable launch system A reusable launch vehicle have parts that can be recovered and reflown, while carrying payloads from the surface to outer space. Rocket stages are the most common launch vehicle parts aimed for reuse. Smaller parts such as rocket engines and boos ...
technology was developed and initially used for the first stages of the Falcon family of rockets it is particularly well suited to the Falcon Heavy where the two outer cores separate from the rocket earlier in the flight, and are therefore moving more slowly at stage separation. For example, on
Falcon 9 flight 20 Falcon 9 flight 20 (also known as Orbcomm OG2 M2) was a Falcon 9 space launch that occurred on 22 December 2015 at 01:29:00 UTC (21 December, 8:29:00 pm local time). It was the first time that the first stage of an orbital rocket made a succ ...
, the speed at separation was close to 6000 km/h and this allowed a return to near the launch site. On flight 22, going to a more-energetic
GTO GTO may refer to: Entertainment * ''Great Teacher Onizuka'', a manga, anime, live-action series, and film * GameTable Online, a game portal Music bands * GTO (band), an Australian band * The GTOs, an American girl group * Giraffe Tongue Orche ...
orbit, the higher velocity at separation was between 8000 and 9000 km/h. At these faster speeds it is not possible to return the booster to near the launch site for a landing; if a landing is attempted it needs to be hundreds of kilometers downrange on an autonomous droneship. Reuse also has an impact on risk estimates. While early customers of reused rockets asked for a lower price, a booster that has flown already has been demonstrated to work under realistic flight conditions. Some customers now prefer reused boosters over new boosters.


Falcon 9 reusability development

In 2013 SpaceX was testing reusable technologies both for its first-stage booster launch vehicle designs (with three test vehicles :
Grasshopper Grasshoppers are a group of insects belonging to the suborder Caelifera. They are among what is possibly the most ancient living group of chewing herbivorous insects, dating back to the early Triassic around 250 million years ago. Grasshopp ...
,
F9R Dev1 Falcon 9 prototypes were experimental flight test reusable rockets that performed vertical takeoffs and landings. The project was privately funded by SpaceX, with no funds provided by any government until later on. Two prototypes were built, ...
, and F9R Dev2) — and for its new reusable
SpaceX Dragon 2 Dragon 2 is a class of partially reusable spacecraft developed and manufactured by American aerospace manufacturer SpaceX, primarily for flights to the International Space Station (ISS). SpaceX has also launched private missions such as Ins ...
space capsule A space capsule is an often-crewed spacecraft that uses a blunt-body reentry capsule to reenter the Earth's atmosphere without wings. Capsules are distinguished from other satellites primarily by the ability to survive reentry and return a payl ...
(with a low-altitude test vehicle called
DragonFly A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat thre ...
). SpaceX has publicly disclosed a multi-element, incremental test program for booster stages that includes four aspects: * low-altitude (less than ), low-velocity testing of its single-engine
Grasshopper Grasshoppers are a group of insects belonging to the suborder Caelifera. They are among what is possibly the most ancient living group of chewing herbivorous insects, dating back to the early Triassic around 250 million years ago. Grasshopp ...
technology-demonstrator at its Texas test site * low-altitude (less than ), low-velocity testing of a much larger, second-generation, three-engine test vehicle called
F9R Dev1 Falcon 9 prototypes were experimental flight test reusable rockets that performed vertical takeoffs and landings. The project was privately funded by SpaceX, with no funds provided by any government until later on. Two prototypes were built, ...
. The second generation vehicle includes extensible landing legs and will be tested at the Texas test site * high-altitude, mid-velocity testing was planned but cancelled in favor of post-mission re-entry tests of first-stage boosters. It would have used F9R Dev2 at a SpaceX leased facility at
Spaceport America Spaceport America, formerly the Southwest Regional Spaceport, is an FAA-licensed spaceport located on of State Trust Land in the Jornada del Muerto desert basin north of Las Cruces, New Mexico, and southeast of Truth or Consequences. Wit ...
in New Mexico. * high-altitude (), very-high-velocity (approximately ; ) ballistic reentry, SpaceX high-altitude controlled-descent tests, controlled-deceleration and controlled-descent tests of post-mission (spent) Falcon 9 booster stages following a subset of Falcon 9 launches that began in 2013. Eight low-altitude booster flight tests were made by Grasshopper in 2012 and 2013. The first booster rocket, booster return controlled-descent test from high-altitude was made in September 2013, with a second test in April, a Falcon 9 Flight 10, third test flight in July and a Falcon 9 Flight 13, fourth test in September 2014. All four test flights to date were intended to be over-water, simulated landings. Five low-altitude booster flight tests of F9R Dev1 were flown during April–August 2014, before the vehicle self-destructed for safety reasons on the fifth flight.


Flight test vehicles

SpaceX used a set of experimental technology-demonstrator, suborbital Reusable launch system, reusable launch vehicles (RLV) to begin flight testing their reusable booster technologies in 2012. Two versions of the prototype reusable test rockets were built—the tall ''Grasshopper'' (formerly designated as ''Grasshopper v1.0'') and the tall ''Falcon 9 Reusable Development Vehicle'', or ''F9R Dev1''—formerly known as ''Grasshopper v1.1''—as well as a space capsule, capsule prototype for testing propulsive landings of the SpaceX Dragon 2, Dragon crew and cargo capsule for the Falcon 9—''DragonFly''. Grasshopper was built in 2011–2012 for low-altitude, low-velocity hover testing that began in September 2012 and concluded in October 2013 after eight test flights. The second prototype vehicle design, F9R Dev1, was built on the much larger Falcon 9 v1.1 booster stage was used to further extend the low-altitude flight testing flight envelope, envelope on a vehicle that better matched the actual flight hardware, and made five test flights in 2014. The low-altitude, low-speed flights of the test vehicle rockets and capsule were conducted at the SpaceX Rocket Development and Test Facility, SpaceX Rocket Test Facility in McGregor, Texas SpaceX indicated in November 2018 that they considered testing a heavily modified Falcon 9 second stage that would look like a "mini-Starship development history#Big Falcon Rocket, BFR Ship" and be used for atmospheric reentry flight testing, testing of a number of technologies needed for the Starship test flight rocket, full-scale spaceship, including an ultra-light heat shield and high-Mach number, Mach control surfaces, SpaceX to build small version of BFR's spaceship for use on Falcon 9, says Elon Musk
. Eric Ralph, Teslarati. 7 November 2018.
but two weeks later, Musk dismissed the approach in favor of using a full-diameter BFR instead.


Grasshopper

Grasshopper, the company's first
VTVL Vertical takeoff, vertical landing (VTVL) is a form of takeoff and landing for rockets. Multiple VTVL craft have flown. The most widely known and commercially successful VTVL rocket is SpaceX's Falcon 9 first stage. VTVL technologies were dev ...
test vehicle, consisted of a Falcon 9 v1.0 first-stage tank, a single Merlin 1D, Merlin-1D engine, and four permanently attached steel landing legs. It stood tall. SpaceX built a concrete launch facility at its Rocket Development and Test Facility in McGregor, Texas to support the Grasshopper flight test program. Grasshopper was also known as Grasshopper version 1.0, or Grasshopper v1.0, prior to 2014 during the time the followon Grasshopper-class test vehicles were being built. In addition to three test flights in 2012, five additional tests were successfully flown by the end of October 2013including the fourth test overall in March 2013in which Grasshopper doubled its highest leap to rise to with a 34-second flight. In the seventh test, in August 2013, the vehicle flew to during a 60-second flight and executed a lateral maneuver before returning to the pad. Grasshopper made its eighth and final test flight on October 7, 2013, flying to before making its eighth successful landing. The Grasshopper test vehicle is now retired.


Falcon 9 Reusable Development Vehicle

As early as October 2012, SpaceX discussed development of a second-generation Grasshopper test vehicle, which was to have lighter landing legs that fold up on the side of the rocket, a different engine bay, and would be nearly 50% longer than the first Grasshopper vehicle. In March 2013, SpaceX announced that the larger Grasshopper-class suborbital flight vehicle would be constructed out of the first-stage tank that was used for qualification testing at the SpaceX Rocket Development and Test Facility in early 2013. It was rebuilt as the with extensible landing legs. Five test flights occurred in 2014. The second VTVL flight test vehicle—F9R Dev1, built on the much longer Falcon 9 v1.1 first-stage tank, with retractable landing legs—made its first test flight on April 17, 2014. F9R Dev1 was used for low-altitude test flights in the McGregor, Texas area—projected maximum altitude below —with a total of five test flights, all made during 2014. This vehicle self-destructed as a safety measure during its fifth test flight on August 22, 2014. By April 2014, a third flight test vehicle—F9R Dev2—was being built and was planned to be flown at the high-altitude test range available at
Spaceport America Spaceport America, formerly the Southwest Regional Spaceport, is an FAA-licensed spaceport located on of State Trust Land in the Jornada del Muerto desert basin north of Las Cruces, New Mexico, and southeast of Truth or Consequences. Wit ...
in New Mexico where it was expected to be flown at altitudes up to -plus. It was never flown as SpaceX moved the high-altitude testing program to its SpaceX Falcon 9 booster post-mission, controlled-descent, test program, controlled-descent testing of used boosters following their use on a paid orbital launch and ascent.


DragonFly

DragonFly A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat thre ...
was a prototype test article (aerospace), test article for a propulsively landed version of the SpaceX Dragon space capsule, capsule, a suborbital spaceflight, suborbital reusable launch vehicle (RLV), intended for low-altitude flight testing. it was planned to undergo a test program in Texas at the McGregor Rocket Test Facility, during 2014–2015. The DragonFly test vehicle is powered by eight SuperDraco engines, arranged in a redundant pattern to support fault-tolerance in the propulsion system design. SuperDracos utilize a storable propellant mixture of monomethyl hydrazine (MMH) fuel and nitrogen tetroxide oxidizer (NTO), the same propellants used in the much smaller Draco (rocket engine family), Draco thrusters used for
attitude control Attitude control is the process of controlling the orientation of an aerospace vehicle with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc. Controlling vehicle ...
and Reaction control system, maneuvering on the first-generation Dragon spacecraft. While SuperDraco engines are capable of of thrust, during use on DragonFly flight test vehicle each will be Rocket engine throttling, throttled to less than to maintain vehicle stability. A test flight program of thirty flights was proposed in 2013–2014, including two ''propulsive assist'' (parachutes plus thrusters) and two ''propulsive landing'' (no parachutes) on flights dropped from a helicopter at an altitude of approximately . The other 26 test flights were projected to take off from a launch pad, pad: eight to be ''propulsive assist hops'' (landing with parachutes plus thrusters) and 18 to be ''full propulsive hops'', similar to the
Grasshopper Grasshoppers are a group of insects belonging to the suborder Caelifera. They are among what is possibly the most ancient living group of chewing herbivorous insects, dating back to the early Triassic around 250 million years ago. Grasshopp ...
and F9R Dev booster stage test flights. , the DragonFly test program was not expected to start until after the completion of the
F9R Dev1 Falcon 9 prototypes were experimental flight test reusable rockets that performed vertical takeoffs and landings. The project was privately funded by SpaceX, with no funds provided by any government until later on. Two prototypes were built, ...
booster testing at the McGregor facility.


Falcon 9 booster post-mission flight tests

In an arrangement highly unusual for launch vehicles, SpaceX began in 2013 using some first stages of the Falcon 9 v1.1 rockets for propulsive-return controlled-descent flight tests after they completed the boost phase of an orbital flight. Since the advent of orbital spaceflight, spaceflight in Sputnik 1, 1957, launch vehicle boosters would ordinarily just be discarded after setting their payloads on their way. The over-water tests started by SpaceX took place in the Pacific and Atlantic oceans south of Vandenberg Air Force Base and east of Cape Canaveral Air Force Station. The first flight test occurred on September 29, 2013, after the second stage with the CASSIOPE and nanosat payloads separated from the booster. These descent and simulated landing tests continued over the next two years, with the second flight test taking place on April 18, 2014, two more test in List of Falcon 9 and Falcon Heavy launches#2014, 2014, and four subsequent tests conducted in 2015. SpaceX continued to make Iterative and incremental development, iterative and incremental changes to the booster design, as well as the specific reusable technologies, descent profile and propellant margins, on some 2016-2018 Falcon 9 and Falcon Heavy flights to tweak the design and operational parameters. Many of these descent and landing tests were tested on active orbital spaceflight missions for SpaceX customers as the booster reentered the atmosphere and attempted recoverable landings.


Re-entry and controlled descent

Following analysis of the flight test data from the first booster-controlled descent in September 2013, SpaceX announced it had successfully tested a large amount of new technology on the flight, and that coupled with the technology advancements made on the Grasshopper low-altitude landing demonstrator, they were ready to test a full recovery of the booster stage. The first flight test was successful; SpaceX said it was "able to successfully transition from vacuum through
hypersonic In aerodynamics, a hypersonic speed is one that exceeds 5 times the speed of sound, often stated as starting at speeds of Mach 5 and above. The precise Mach number at which a craft can be said to be flying at hypersonic speed varies, since ind ...
, through
supersonic Supersonic speed is the speed of an object that exceeds the speed of sound ( Mach 1). For objects traveling in dry air of a temperature of 20 °C (68 °F) at sea level, this speed is approximately . Speeds greater than five times ...
, through
transonic Transonic (or transsonic) flow is air flowing around an object at a speed that generates regions of both subsonic and supersonic airflow around that object. The exact range of speeds depends on the object's critical Mach number, but transoni ...
, and light the engines all the way and control the stage all the way through [the atmosphere]". Musk said, "the next attempt to recovery [sic] the Falcon 9 first stage will be on the fourth flight of the upgraded rocket. This would be hethird commercial Dragon cargo flight to ISS." This second flight test took place during the April 2014 Dragon flight to the ISS. SpaceX attached Launch vehicle landing gear, landing legs to the first stage, decelerated it over the ocean and attempted a simulated landing over the water, following the ignition of the second stage on the SpaceX CRS-3, third cargo resupply mission contracted to NASA. The first stage was successfully slowed down enough for a soft landing over the Atlantic Ocean. SpaceX announced in February 2014 the intent to continue the tests to land the first-stage booster in the ocean until precision control from hypersonic all the way through subsonic regimes has been proven. Five additional controlled-descent tests were conducted in the remainder of 2014 through April 2015, including two attempts to land on a
floating landing platform A floating launch vehicle operations platform is a marine vessel used for launch or landing operations of an orbital launch vehicle by a launch service provider: putting satellites into orbit around Earth or another celestial body, or recovering ...
—a SpaceX-built Autonomous Spaceport Drone Ship—on the Atlantic Ocean east of the launch site, both of which brought the vehicle to the landing platform, but neither of which resulted in a successful landing.


First landing on ground pad

During the SpaceX CRS-7, 2015 launch hiatus, SpaceX requested regulatory approval from the FAA to attempt returning their Falcon 9 Flight 20, next flight to CCAFS, Cape Canaveral instead of targeting a floating platform in the ocean. The goal was to VTVL, land the booster vertically at the leased ''Landing Zone 1'' facility—the former Launch Complex 13 where SpaceX had recently built a large rocket landing pad. The FAA approved the safety plan for the ground landing on December 18, 2015. The first stage landed successfully on target at 20:38 local time on December 21 (01:38 UTC on December 22). First stage booster ''B1019'' never flew again after the flight. Rather, the rocket was moved a few miles north to the SpaceX hangar facilities at Launch pad 39A, recently refurbished by SpaceX at the adjacent Kennedy Space Center, where it was inspected before being used on January 15, 2016, to conduct a static fire test on its original launchpad, Launch Complex 40. This test aimed to assess the health of the recovered booster and the capability of this rocket design to fly repeatedly in the future. The tests delivered good overall results except for one of the outer engines experiencing thrust fluctuations. Elon Musk reported that this may have been due to debris ingestion. The booster was then retired to the SpaceX facility in Hawthorne, California.


Landing attempts on drone ships

Falcon 9 Flight 21 launched the Jason-3 satellite on January 17, 2016, and attempted to land on the autonomous spaceport drone ship, floating platform ''Just Read the Instructions'', located for the first time about out in the Pacific Ocean. Approximately 9 minutes into the flight, the live video feed from the drone ship went down due to the losing its lock on the uplink satellite. The vehicle landed smoothly onto the vessel but one of the four landing legs failed to lock properly, reportedly due to ice from the heavy pre-launch fog preventing a lockout collet from latching. Consequently the booster fell over shortly after touchdown and was destroyed in a deflagration upon impact with the pad. Falcon 9 Flight 22, Flight 22 was carrying a heavy payload of to geostationary transfer orbit (GTO). This was heavier than previously advertised maximum lift capacity to GTO being made possible by going slightly subsynchronous orbit, subsynchronous. Following delays caused by failure of Falcon 9 Flight 19, Flight 19, SpaceX agreed to provide extra thrust to the SES-9 satellite to take it supersynchronous orbit, supersynchronous. As a result of these factors, there was little propellant left to execute a full reentry and landing test with normal margins. Consequently the Falcon 9 first stage followed a ballistic trajectory after separation and re-entered the atmosphere at high velocity, making it less likely to land successfully. The atmospheric re-entry and controlled descent were successful despite the higher aerodynamical constraints on the first stage due to extra speed. However the rocket was moving too fast and was destroyed when it collided with the drone ship. SpaceX collected valuable data on the extended flight envelope required to recover boosters from GTO missions.


First landings at sea

Starting in January 2015, SpaceX positioned stable floating platforms a few hundred miles off the coast along the rocket trajectory; those transformed barges were called
autonomous spaceport drone ship An autonomous spaceport drone ship (ASDS) is an ocean-going vessel derived from a deck barge, outfitted with station-keeping engines and a large landing platform and is autonomously controlled when on station for a landing. Construction of ...
s. On April 8, 2016, Falcon 9 Flight 23, the third flight of Falcon 9 Full Thrust, the full-thrust version, delivered the SpaceX CRS-8 cargo on its way to the International Space Station while the Falcon 9 booster B1021, first stage conducted a boostback and re-entry maneuver over the Atlantic ocean. Nine minutes after liftoff, the booster landed vertically on the drone ship ''Of Course I Still Love You'', 300 km from the Florida coastline, achieving a long-sought-after milestone for the SpaceX reusability development program. A second successful drone ship landing occurred on May 6, 2016, with the next flight which launched JCSAT-14 to GTO. This second landing at sea was more difficult than the previous one because the booster at separation was traveling about compared to on the CRS-8 launch to
low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never m ...
. Pursuing their experiments to test the limits of the flight envelope, SpaceX opted for a shorter landing burn with three engines instead of the single-engine burns seen in earlier attempts; this approach consumes less fuel by leaving the stage in free fall as long as possible and decelerating more sharply, thereby minimizing the amount of energy expended to counter gravity. Elon Musk indicated this first stage may not be flown again instead being used as a life leader for ground tests to confirm others are good. A third successful landing followed on 27 May, again following deceleration from the high speed required for a GTO launch. The landing crushed a "crush core" in one leg, leading to a notable tilt to the stage as it stood on the drone ship.


Routine procedure

Over the subsequent missions, landing of the first stage gradually became a routine procedure, and since January 2017 SpaceX ceased to refer to their landing attempts as "experimental". Low-energy missions to the ISS fly back to the launch site and land at Landing Zone 1, LZ-1, whereas more demanding satellite missions land on drone ships a few hundred miles downrange. Occasional missions with heavy payloads, such as EchoStar 23, do not attempt to land, flying in Expendable launch system, expendable configuration without fins and legs. During 2016 and 2017, SpaceX has recovered a number of first stages to both land and drone ships, helping them optimize the procedures needed to re-use the boosters rapidly. In January 2016 Elon Musk estimated the likelihood of success at 70 percent for all landing attempts in 2016, hopefully rising to 90 percent in 2017; he also cautioned that we should expect "a few more RUDs" (''Rapid Unscheduled Disassembly'', Musk's acronym to denote destruction of the vehicle on impact). Musk's prediction was vindicated, as 5 out of 8 flown boosters () were recovered in 2016, and 14 out of 14 () in 2017. Three GTO missions for heavy payloads (EchoStar#Satellite fleet, EchoStar 23 in March 2017, Inmarsat-5 F4 in May 2017 and Intelsat 35e in July 2017) were flown in an expendable launch system, expendable configuration, not equipped for landing. One booster which could have been recovered was intentionally flown without legs and left to sink after a soft touchdown in the ocean (booster B1036 for the Iridium NEXT 31–40 mission in December 2017).


First-stage reuse

, SpaceX had List of Falcon 9 first-stage boosters, recovered 21 first-stage boosters from previous missions, of which six were recovered twice, yielding a total 27 landings. In 2017, SpaceX flew a total of 5 missions out of 20 with re-used boosters (). In total, 14 boosters have been re-flown . On July 28, 2016, the first stage from the JCSAT-2B mission was successfully test-fired for a full duration at the SpaceX McGregor facility. The first reuse attempt occurred on 30 March 2017 with the launch of SES-10, resulting in a successful flight and second landing of the Falcon 9 booster B1021, B1021 first stage recovered from the SpaceX CRS-8, CRS-8 mission of April 2016. Another reflight succeeded in June 2017 with BulgariaSat-1 riding the B1029 booster from the January 2017 Iridium NEXT mission. Booster B1031 flew the CRS-10 mission to the ISS in February 2017 and helped loft communications satellite
SES-11 SES-11 / EchoStar 105 is a geostationary communications satellite operated by SES S.A. and EchoStar and designed and manufactured by Airbus Defence and Space. It has a mass of and has a design life of at least 15 years. The spacecraft had bee ...
to geostationary orbit in October 2017. Boosters B1035 and B1036 were flown twice each for the same customer, B1035 for
NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeedin ...
missions CRS-11 and CRS-13 in June and December 2017, and B1036 for two batches of 10 Iridium NEXT satellites, also in June and December 2017. B1032 was re-used for GovSat-1 in January 2018 after List of NRO launches#Launch history, NROL-76 in May 2017. SpaceX spent four months refurbishing the first booster to be re-used, B1021, and launched it again after approximately one year. The second booster to be flown again, B1029, was refurbished in "only a couple of months" and re-launched after five months. Elon Musk has stated a goal to turn around a first stage within 24 hours. Musk remains convinced that this long-term goal can be met by SpaceX rocket technology, but has not stated that the goal would be achieved with the Falcon 9 design. Boosters B1019 and B1021 were retired and put on display. B1029 was also retired after the BulgariaSat-1 mission. B1023, B1025, B1031 and B1035 were recovered a second time, while B1032 and B1036 were deliberately sunk at sea after a soft ocean touchdown. By mid-2019, having reflown any single booster only three times to date, SpaceX indicated that they plan to use a single booster at least five times by the end of 2019. No booster achieved this timeline, but Falcon 9 booster B1048, B1048 flew four times and two more (Falcon 9 booster B1046, B1046 and Falcon 9 booster B1049, B1049) made a fourth flight in January 2020. In March 2020, SpaceX first flew a booster (Falcon 9 booster B1048, B1048) for the fifth time.


Falcon Heavy reusability

Falcon Heavy test flight had no contracted customer, and in order to limit the cost on such a test flight, SpaceX targeted to have reused side-boosters. Boosters B1023 and B1025 that had been flown as a Falcon 9 configuration, were reconfigured and used as side boosters on the first flight of Falcon Heavy in February 2018, and then both landed side-by-side at almost the same time on the ground pads. Later Falcon Heavy flights used either new boosters, or side-boosters previously flown on a Falcon Heavy. SpaceX has been unable to recover the central core in any of the three Falcon Heavy, but managed to recover all the six-side boosters.


Block 5 boosters

With a streak of 19 successful recovery attempts of the first stage from 2016 through to early 2018, SpaceX has focused on rapid reusability of first stage boosters. Block 3 and Block 4 proved economically feasible to be flown twice, as 11 such boosters have been reflown in 2017 and 2018. Falcon 9 Full Thrust Block 5, Block 5 has been designed with multiple reuses in mind, up to 10 reuses with minimal inspection and up to 100 uses with refurbishment. New aggressive reentry profiles were experimented with expendable Block 3 and Block 4 boosters in early 2018, to test out the limitations on the range of recoverable launch margins that are potential for future Block 5. On 9 May 2021, B1051 became the first booster to be launched and landed for the tenth time, achieving one of SpaceX's milestone goals for reuse.


Fairing reuse

Payload fairings have traditionally been Expendable payload fairing, expendable, where they have either burned up in the atmosphere or were destroyed upon impacting the ocean. As early as mid-2015, Musk hinted that SpaceX might be working on fairing reusability, following the discovery of wreckage of an unidentified Falcon 9 launch vehicle section off the coast of The Bahamas, and was subsequently confirmed by SpaceX to be a component of a payload fairing that had washed ashore. By April 2016, SpaceX had publicly announced Falcon 9 fairing recovery as an objective. The cost of the fairing is about $6 million per launch, which accounts for approximately ten percent of the overall launch costs. Musk said in 2017: "Imagine if you had $6 million in cash in a pallet flying through the air, and it was going to smash into the ocean. Would you try to recover that? Yes, yes you would." In March 2017, as part of the SES-10 mission, SpaceX for the first time performed a controlled landing of the payload fairing and successfully recovered a fairing half, aided by Attitude control thruster, attitude-control thrusters and a steerable parachute, helping it glide towards a gentle touchdown on water. The company announced intent to land the fairings eventually on a dry flexible structure, jokingly described by Musk as a "floating bouncy-castle", with the aim of full fairing reuse. With successive tests and refinements on several flights, intact fairing recovery was stated as an objective for 2017, with reflight of a recovered fairing planned in 2018. The "bouncy castle" meme was in fact a net strung between large arms of a fast platform supply vessel named ''Mr. Steven, Mr. Steven (now GO Ms. Tree)''. The recovery vessel is equipped with dynamic positioning systems, and was tested after the launch of the Paz (satellite), Paz satellite from Vandenberg Air Force Base in 2017. This mission was also the first to use a version 2 fairing, explicitly designed to "improve survivability for post-launch recovery attempts, and to be reusable on future missions". This recovery attempt was not fully successful; the fairing missed the boat by a few hundred meters but landed intact in the water before being recovered and taken back to port. , all four attempts by SpaceX to land a fairing on a recovery ship had failed, despite fitting ''Mr. Steven'' with larger nets before the July 2018 attempt. In October 2018, at least two fairing recovery tests were performed, involving ''Mr. Steven'' and a helicopter, which would drop a fairing half from the height of about 3300 meters. The outcome of the tests was unclear. In April 2019, during the second Falcon Heavy mission, recovery boat ''Go Searcher'' fished the fairing halves out of the sea and it was announced the fairings would be used on a Starlink (satellite constellation), Starlink mission. These fairings were reused in a Starlink mission on 11 November 2019. In June 2019, following the third Falcon Heavy launch, the first successful fairing catch was made. Images posted to Twitter hours after launch showed one half of the fairing nestled in the net of the recovery vessel ''GO Ms. Tree''. By late 2020, payload fairings were being regularly recovered by SpaceX, with SpaceX dispatching two custom-modified recovery ships—''Ms. Tree (ship), Ms. Tree'' and ''Ms. Chief''—to collect the fairings on most launches from their Florida launch site. By this time, SpaceX was also regularly reflying recovered fairings on launches, usually on their own flights where Starlink satellites are the primary payload, primary or only payload. however, successful net landings were not yet routine, with less than half of the fairings of the previous three months being caught in the nets, but most still recovered anyway after a soft landing in the ocean. By April 2021, SpaceX had abandoned the experimental program to attempt recovery of dry payload fairings under parachute descent in a net on a platform supply vessel, fast ship. SpaceX decided to operationalize "wet recovery" of fairings on future Falcon 9 flights, having found that they can clean, refurbish, and reuse such fairings more economically. SpaceX released ''Miss Tree'' and ''Miss Chief'' from their contracts and purchased two ships for fairing recovery operations as well as for towing and supporting Autonomous spaceport drone ship, droneships on the east coast. These two ships were named in honour of Demo-2 astronauts Doug Hurley and Bob Behnken as ''Doug'' and ''Bob''. The earlier names of the ships Bob and Doug were Ella G and Ingrid respectively. Currently, Doug is operating at Port Canaveral while Bob is at Tampa undergoing construction. By 26 May 2021, SpaceX had launched 40 flights that reflew at least one previously-flown fairing half, and one fairing had flown on five different flights, having been recovered and cleaned four previous times.


Second-stage reuse

Despite early public statements that SpaceX would endeavor to make the Falcon 9 second-stage reusable as well, by late 2014, they determined that the mass needed for a re-entry heat shield, landing engines, and other equipment to support recovery of the second stage as well as the diversion of development resources from other company objectives was at that time prohibitive, and indefinitely suspended their second-stage reusability plans for the Falcon rockets. However, in July 2017 they indicated that they might do Flight test, experimental tests on recovering one or more second-stages in order to learn more about reusability to inform their
Starship A starship, starcraft, or interstellar spacecraft is a theoretical spacecraft designed for traveling between planetary systems. The term is mostly found in science fiction. Reference to a "star-ship" appears as early as 1882 in '' Oahspe: A Ne ...
development process, and in May 2018 provided additional details about how they might carry out some of that testing. The Starship is planned to replace all existing SpaceX launch and space vehicles after the mid-2020s:
Falcon 9 Falcon 9 is a partially reusable medium lift launch vehicle that can carry cargo and crew into Earth orbit, produced by American aerospace company SpaceX. The rocket has two stages. The first (booster) stage carries the second stage and pay ...
, Falcon Heavy and the Dragon spacecraft, aimed initially at the Earth-orbit Space launch market competition, launch market but with capability to support Beyond Earth orbit, long-duration spaceflight in the cislunar and Exploration of Mars, Mars mission environments. Both stages will be fully reusable. The integrated second stage, second-stage-with-Spacecraft, spaceship design has not been used in previous launch vehicles.


Reuse of Dragon capsules

SpaceX's Dragon capsules have been gradually improved for reuse. Structural elements and internal components are being refurbished between flights, while the heat shield is replaced for each new mission. The last newly built Dragon cargo capsule first flew in July 2017; all subsequent ISS resupply missions were conducted with refurbished capsules, some capsules made a third flight. Dragon's trunk section cannot be reused, as it is designed to burn up in the atmosphere after completing its mission.
SpaceX Dragon 2 Dragon 2 is a class of partially reusable spacecraft developed and manufactured by American aerospace manufacturer SpaceX, primarily for flights to the International Space Station (ISS). SpaceX has also launched private missions such as Ins ...
is planned to be reused as well. Initially it was planned to use new capsules for all crewed NASA missions but experience with the demonstration missions lead to NASA and SpaceX agreeing on reuse starting from SpaceX Crew-2, Crew-2.


Operational flow

In the first year of successful stage return from the experimental test flights, SpaceX performed ''ad hoc'' and flight-specific evaluation and component testing on each successfully landed stage. Stages were processed and initially evaluated in either launch hangars, or for Cape Canaveral landings, in the new hangar SpaceX recently completed at Kennedy Space Center Launch Complex 39. Returned rocket parts have also been transported to SpaceX Hawthorne and SpaceX McGregor for engineering evaluation and testing. In February 2017, after eight rocket cores had successfully landed — seven of them having launched from Cape Canaveral — SpaceX announced plans to expand their physical facilities to process and refurbish rockets. They will do so in both leased space and in a new building to be built in Port Canaveral, Florida, near the location where the Atlantic Autonomous Spaceport Drone Ship is berthed, and where stages that land on the East Coast of the United States, east-coast droneship are now removed from the ship.


Starship reusability development

The goal of Starship launch system is to be a fully reusable orbital launch and reentry vehicle. The Starship launch system consists of two stages: a Super Heavy booster and a Starship spacecraft; both have a body made from SAE 304 stainless steel, SAE 304L stainless steel and are designed to hold liquid oxygen and liquid methane. Super Heavy and then Starship will boost the rocket up to orbital speed, after which both of them will land and can be used again. Starship can send more than to
low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never m ...
; higher Earth and other orbits are accessible after being refueled by tanker Starships. Future planned Starship variants will be able to land on the Moon and
Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin at ...
. Starship's design has influenced other launch vehicles, such as the Terran R's full reusability capability.


Design history

The first reference by SpaceX of a rocket concept with Starship lifting capabilities was in 2005. In a student conference, Musk briefly mentioned a theoretical Heavy-lift launch vehicle, heavy‑lift launch vehicle code-named BFR, later known as the Falcon XX. It would be powered by a larger version of the SpaceX Merlin, Merlin engine, called Merlin 2, and feature a lifting capability of to low Earth orbit. In 2012, in a public discussion about a conceptual Mars colonization program, Musk described the Mars Colonial Transporter. He envisioned it as a reusable super heavy-lift launch vehicle that could deliver approximately to
low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never m ...
. The Mars Colonial Transporter might be powered by Raptors, consuming liquid methane and liquid oxygen. In September 2016, at the 67th International Astronautical Congress, Musk announced the Interplanetary Transport System (ITS), a conceptual reusable rocket conceived to launch humans to Mars and other destinations in the Solar System. The ITS was to be tall, wide, and capable of lifting to low Earth orbit. Both stages were to be made from Carbon-fiber-reinforced polymers, carbon composites. The first stage or booster was to be powered by 42 Raptors, and the second stage by nine Raptors. Once refueled while in Earth orbit, the spacecraft Delta-v, could accelerate to Mars. When an Interplanetary Spaceship enters the atmosphere, it cools itself via Transpiration cooling, transpiration and controls the spacecraft's descent by moving its delta wings and split flaps. At the following Congress, Musk announced a replacement rocket called the Big Falcon Rocket or informally Big Fucking Rocket. The Big Falcon Rocket is tall and wide. In that conference, he talked about a possible Sub-orbital spaceflight#Sub-orbital transportation, suborbital transportation feature and termed it Earth to Earth. In November 2018, the present names were first used: Super Heavy for the booster, Starship for the spacecraft, and Starship system or just Starship for the whole vehicle. Around that time, Musk announced a redesigned spacecraft concept with three aft flaps and two forward flaps. In January 2019, Musk announced that Starship would be made from stainless steel and stated that this might be stronger than an equivalent carbon composite in a wide range of temperatures. In March, Musk tweeted that SpaceX opted for a heat shield composed of hexagonal ceramic tiles instead of transpiration. In October, the Starship spacecraft's engine configuration was changed to three Raptors optimized for atmospheric pressure and three optimized for space. The number of rear fins was reduced from three to two and placed at the heat shield's edges.


Testing

On 27 August 2019, a simplified test article named ''Starhopper'' hopped high. Unveiled in a SpaceX event in September 2019, Starship Mk1 (Mark 1) was the first full‑scale Starship test article to be built. The Mk2 in Florida was constructed five months later. Neither flew: Mk1 was destroyed during a cryogenic proof test and Mk2 was scrapped. In early 2020, SpaceX changed Mk3's name to SN1 (serial number 1). During a cryogenic proof test on 28 February 2021, a fault in SN1's bottom tank caused it to crumble. On 8 March 2020, SN2 stripped-down test tank completed its only cryogenic proof test. On 3 April 2020, during SN3's cryogenic proof test, a valve leaked the liquid nitrogen inside its lower tank, causing the vessel to depressurize and collapse. After SN4's fifth successful static fire test on 29 May 2020, the Quick connect fitting, quick disconnect fuel line caused it to explode. On 15 June 2020, Musk tweeted that new prototypes would be made from SAE 304 stainless steel, SAE 304L instead of 301 stainless steel. On 4 August 2020, SN5 completed a hop using a single Raptor, the first full-scale test article to complete a flight test intact. On 24 August 2020, SN6 replicated SN5's flight path successfully. SN7 was not completed, but as of October 2021, its tanks were salvaged for various experiments. SN8 was the first complete test article. In October and November 2020, SN8 underwent four static fire tests; the first, second, and fourth were successful, but the third caused an engine shutdown. According to Musk, the force from the engine destroyed parts of the launch pad sending some pieces of it into the engine. On 9 December 2020, SN8 performed the first flight by a Starship, reaching an altitude of . During landing, its methane header tank did not provide sufficient fuel to the Raptors, reducing thrust from one engine. The test article exploded on impact. On 2 February 2021, SN9 flew high. While descending, one of its engines did not function and burst on landing at an angle. On 3 March 2021, SN10 repeated SN9's flight path, then Hard landing, hard landed and destroyed itself in an explosion 8 minutes later. The first Super Heavy booster named BN1 (booster number 1) finished construction on 8 March 2021, but it had not received engines. On 30 March 2021, SN11 exploded in midair without a confirmed explanation because of the dense fog at the launch site. A possible explanation is that an engine might have burned the test article's avionics and could have caused a hard start on the engine's turbopump. After the launch, SpaceX skipped SN12, SN13, SN14, and BN2, and incorporated obsolete test articles' improvements to SN15 instead. On 5 May 2021, the test article flew the same flight path as previous test articles and Soft landing (aeronautics), soft landed successfully. On 20 July 2021, BN3 fired its engines for the only time. As of October 2021, SN15, SN16, and BN3 had been retired and displayed. As of October 2021, skipping over SN16, SN17, SN18, and SN19, SN20 along with BN4 are targeted to an orbital flight scheduled for late 2021. However, a NASA public document that outlines NASA's plan to observe Starship's reentry inferred that the launch might happen near March 2022. However, the article did not specify that the observed flight would be the first test flight of the Starship, so an approximate launch date is still unknown. The Federal Aviation Administration (FAA) has not approved the environmental impact statement draft released on 19 September 2021. BN4 is expected to separate about three minutes into the orbital flight and splashdown in the Gulf of Mexico, approximately from the shoreline. The rocket's SN20 second stage ground track will then traverse the middle of the Straits of Florida between Key West and Cuba, a range safety consideration to assure any debris from a malfunction falls away from populated areas. Once over the Atlantic Ocean, SN20 is then expected to accelerate close to orbital speed and splashdown around ninety minutes later northwest of Kauai, Hawaii. File:Mk1 starship.jpg, alt=Photograph of equipment in front of white tents, with a steel nose cone at the back, Starship Mk1's nose cone near construction tents File:SpaceX Starhopper.jpg, alt=Photograph of a short steel rocket stage with its fins touching the ground, ''Starhopper'' in construction File:Starship sn5.jpg, alt=Photograph of a crane hooking onto a steel vessel body, A crane lifting Starship SN5 File:Tanksn7.1.jpg, alt=Photograph of a steel tank, Starship SN7's tank File:Starship SN9 Open Rear Flap.jpg, alt=Photograph of a spacecraft with a pair of steel flaps on top and bottom, Starship SN9 on the launchpad File:Starship SN20 getting a tile inspection.jpg, alt=Photograph of a worker on an aerial work platform repairing a spacecraft's black heatshield, A worker is examining Starship SN20's ceramic tiles


See also

* New Shepard, a sub-orbital VTVL system * Grasshopper (rocket)


Notes


References


External links


Video of 8th and final low-altitude Grasshopper v1.0 test flight
to , October 7, 2013.

* [https://www.youtube.com/watch?v=0UjWqQPWmsY Video of Falcon 9 Reusable Development vehicle no. 1 (F9R Dev1) 1st test flight], to , hovering and then landing just next to the launch stand, April 17, 2014. * Video of CRS-3 booster stage landing test, April 2014
low quality, corrupted data
an
higher quality, after video frames recovered by open-source recovery effort by NSF team
* On-board camera video of ORBCOMM Mission-1 booster stage landing test
Falcon 9 First Stage Return : ORBCOMM Mission
SpaceX-released video of the controlled descent test, July 2014. * Chase-plane camera video of ORBCOMM Mission-1 booster stage landing test
Falcon 9 First Stage Reentry Footage from Plane
SpaceX-released video of the controlled descent test, released August 14, 2014.

Reuters, Irene Klotz, January 10, 2015. {{Reusable launch systems Engineering projects Reusable spaceflight technology SpaceX Articles containing video clips