An autonomous spaceport drone ship (ASDS) is an ocean-going vessel derived from a deck

barge Barge nowadays generally refers to a flat-bottomed inland waterway vessel which does not have its own means of mechanical propulsion. The first modern barges were pulled by tugs, but nowadays most are pushed by pusher boats, or other vessels ...

, outfitted with station-keeping engines and a large landing platform and is autonomously controlled when on station for a landing. Construction of such ships was commissioned by aerospace company SpaceX to allow recovery of

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 ...

first stages at

sea The sea, connected as the world ocean or simply the ocean, is the body of salty water that covers approximately 71% of the Earth's surface. The word sea is also used to denote second-order sections of the sea, such as the Mediterranean Sea, ...

for missions that do not carry enough fuel to return to the launch site after boosting

spacecraft A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, p ...

onto an orbital or interplanetary trajectory. SpaceX has three operational drone ships: ''Just Read the Instructions (II)'' (JRTI) and ''A Shortfall of Gravitas'' (ASOG), operating in the

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

for launches from

Kennedy Space Center The John F. Kennedy Space Center (KSC, originally known as the NASA Launch Operations Center), located on Merritt Island, Florida, is one of the National Aeronautics and Space Administration's (NASA) ten field centers. Since December 1968 ...

and

Cape Canaveral Space Force Station Cape Canaveral Space Force Station (CCSFS) is an installation of the United States Space Force's Space Launch Delta 45, located on Cape Canaveral in Brevard County, Florida. Headquartered at the nearby Patrick Space Force Base, the statio ...

, and ''Of Course I Still Love You'' (OCISLY), operating in the

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...

for supporting missions from

Vandenberg Space Force Base Vandenberg Space Force Base , previously Vandenberg Air Force Base, is a United States Space Force Base in Santa Barbara County, California. Established in 1941, Vandenberg Space Force Base is a space launch base, launching spacecraft from ...

. JRTI operated in the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contin ...

for

Vandenberg Air Force Base Vandenberg may refer to: * Vandenberg (surname), including a list of people with the name * USNS ''General Hoyt S. Vandenberg'' (T-AGM-10), transport ship in the United States Navy, sank as an artificial reef in Key West, Florida * Vandenberg Sp ...

launches from 2016 to 2019 before leaving the Port of Los Angeles in August 2019. The ASDS are a key early operational component in the SpaceX objective to significantly lower the price of space launch services through "full and rapid reusability" and were developed as part of the multi-year reusable rocket development program SpaceX undertook to engineer the technology. SpaceX offers three options, depending on launch requirements, landing on land, landing at sea or expending the first stage, in order of increased performance and cost. Any Falcon flights going to geostationary orbit or exceeding

escape velocity In celestial mechanics, escape velocity or escape speed is the minimum speed needed for a free, non- propelled object to escape from the gravitational influence of a primary body, thus reaching an infinite distance from it. It is typically ...

require landing at sea, or expending the first stage. Less demanding launches from Florida can return to

Landing Zones 1 and 2 Landing Zone 1 and Landing Zone 2, also known as LZ-1 and LZ-2 respectively, are landing facilities on Cape Canaveral Space Force Station for recovering components of SpaceX's VTVL reusable launch vehicles. LZ-1 and LZ-2 were built on land le ...

at Cape Canaveral Space Force Station. Around three quarters of recovered Falcon boosters land at sea .

History

In 2009, SpaceX 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 ...

articulated ambitions for "creating a paradigm shift in the traditional approach for reusing rocket hardware". In October 2014, SpaceX publicly announced that they had contracted with a

Louisiana Louisiana , group=pronunciation (French: ''La Louisiane'') is a state in the Deep South and South Central regions of the United States. It is the 20th-smallest by area and the 25th most populous of the 50 U.S. states. Louisiana is borde ...

shipyard to build a floating landing platform for reusable orbital

s. Early information indicated that the platform would carry an approximately landing pad and would be capable of precision positioning so that the platform could hold its position for launch vehicle landing. On 22 November 2014, Musk released a photograph of the "autonomous spaceport drone ship" along with additional details of its construction and size. As of December 2014, the first drone ship used, the McDonough Marine Service's ''Marmac 300'' barge, was based in

Jacksonville, Florida Jacksonville is a city located on the Atlantic coast of northeast Florida, the most populous city proper in the state and is the List of United States cities by area, largest city by area in the contiguous United States as of 2020. It is the co ...

, at the northern tip of the

JAXPORT Cruise Terminal The JAXPORT Cruise Terminal () is a "temporary" cruise ship terminal in Jacksonville, Florida. The facility located at the northwest corner of the ''Dames Point Marine Terminal'', beside the Dames Point Bridge. It was completed in six months durin ...

, where SpaceX built a stand to secure the Falcon stage during post-landing operations. The stand consisted of four , tall and wide pedestal structures bolted to a concrete base. A mobile crane would have lifted the stage from the ship and placed it on the stand. Tasks such as removing or folding back the landing legs prior to placing the stage in a horizontal position for trucking would have been undertaken while the booster was on the stand. The ASDS landing location for the first landing test was in the Atlantic approximately northeast of the launch location at Cape Canaveral, and southeast of Charleston, South Carolina. On 23 January 2015, during repairs to the ship following the unsuccessful first test, Musk announced that the ship was to be named ''Just Read the Instructions'', with a sister ship planned for West Coast launches to be named ''Of Course I Still Love You'' (OCISLY). On 29 January 2015, SpaceX released a manipulated photo of the ship with the name illustrating how it would look once painted. The first ''Just Read the Instructions'' was retired in May 2015 after approximately six months of service in the

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

, and its duties were assumed by ''Of Course I Still Love You''. The former ASDS was modified by removing the wing extensions that had extended the barge surface and the equipment (thrusters, cameras, and communications gear) that had been added to refit it as an ASDS; these items were saved for future reuse. In 2018, Elon Musk announced plans for an additional barge, ''A Shortfall of Gravitas'' (''ASOG''), to support East Coast operationsSpaceX to attempt five recoveries in less than two weeks as fleet activity ramps up
, NASASpaceFlight.com, 19 July 2018, accessed 2 August 2018. but the build of the droneship was delayed, and instead ''JRTI'' was moved to the East Coast and began operations in June 2020. ''ASOG'' was completed in July 2021. By June 2020, SpaceX had received the ability to use "its own private Automatic Identification System (AIS) aids to navigation (ATON) to mark the temporary exclusion areas it uses during rocket launches

rom Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * ...

Cape Canaveral, Florida", the first such use of dynamic restricted area ever approved by the

U.S. Coast Guard The United States Coast Guard (USCG) is the maritime security, search and rescue, and law enforcement service branch of the United States Armed Forces and one of the country's eight uniformed services. The service is a maritime, military, mul ...

The active ASDS fleet

Since early 2016, SpaceX has operated two leased deck barges — ''Marmac 303'' and ''Marmac 304'' – which have been converted to become autonomous-operation-capable ASDS ships. These constituted the active ASDS fleet until July 2021, when ''A Shortfall of Gravitas'' – ''Marmac 302'' – joined the fleet.

''Of Course I Still Love You''

The second ASDS barge, ''Of Course I Still Love You'' (''OCISLY''), had been under construction in a

shipyard since early 2015 using a different hull – ''Marmac 304'' – in order to service launches on the East Coast of the United States. It was converted as a replacement for the first ''Just Read the Instructions'' and entered operational service for Falcon 9 Flight 19 in late June 2015. As of June 2015, its home port was Port of Jacksonville,

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

, but after December 2015, it was transferred further south, at

Port Canaveral Port Canaveral is a cruise, cargo, and naval port in Brevard County, Florida, United States. It is one of the busiest cruise ports in the world with 4.5 million cruise passengers passing through during 2016. Over 5.4 million tonnes of bulk car ...

. While the dimensions of the ship are nearly identical to the first ASDS, several enhancements were made including a steel blast wall erected between the aft containers and the landing deck. The ship was in place for a first-stage landing test on the

SpaceX CRS-7 SpaceX CRS-7, also known as SpX-7, was a private American Commercial Resupply Service mission to the International Space Station, contracted to NASA, which launched and failed on June 28, 2015. It disintegrated 139 seconds into the flight aft ...

mission, which failed on launch on 28 June 2015. On 8 April 2016, the first stage, which launched the Dragon

SpaceX CRS-8 SpaceX CRS-8, also known as SpX-8, was a Commercial Resupply Service mission to the International Space Station (ISS) which was launched on April 8, 2016, at 20:43 UTC. It was the 23rd flight of a Falcon 9 rocket, the tenth flight of a ...

spacecraft, successfully landed for the first time ever on ''OCISLY'', which is also the first ever drone ship landing. In February 2018, the central core of

Falcon Heavy Test Flight The Falcon Heavy test flight (also known as the Falcon Heavy demonstration mission) was the first attempt by SpaceX to launch a Falcon Heavy rocket on February 6, 2018, at 20:45 UTC. The successful test introduced the Falcon Heavy as the m ...

exploded near ''OCISLY'', which damaged two of the four thrusters on the drone ship. Two thrusters were removed from the ''Marmac 303'' barge in order to repair ''OCISLY''. On 30 May 2020, the first stage of the

Crew Dragon Demo-2 Crew Dragon Demo-2 (officially Crew Demo-2, SpaceX Demo-2, or Demonstration Mission-2) was the first crewed test flight of the Crew Dragon spacecraft. The spacecraft, named '' Endeavour'', launched on 30 May 2020 on a Falcon 9 booster, and ca ...

mission landed on ''OCISLY'', with the Crew Demo-2 mission marking both the first launch of American astronauts, from American soil, on an American launch vehicle since the final flight of the Space Shuttle (STS-135) in 2011, and the first launch of astronauts aboard a SpaceX launch vehicle. This marked the first time in history that the first stage of a rocket launched a crew into space and then landed itself safely. ''OCISLY'' is currently based at the

Port of Long Beach The Port of Long Beach, also known as the Harbor Department of the City of Long Beach, is a container port in the United States, which adjoins Port of Los Angeles. Acting as a major gateway for US–Asian trade, the port occupies of land with ...

to support West Coast launches from Vandenberg.

''Just Read the Instructions''

SpaceX first launch vehicle landing barge (''Marmac 300''), and also its third (''Marmac 303''), were both named ''Just Read the Instructions'' (''JRTI''). In fact, some of the parts from the original hull/barge were used to build the ''Marmac 303'' ASDS. The original, ''Marmac 300'', was scrapped after the

SpaceX CRS-6 SpaceX CRS-6, also known as SpX-6, was a Commercial Resupply Service mission to the International Space Station, contracted to NASA. It was the eighth flight for SpaceX's uncrewed Dragon cargo spacecraft and the sixth SpaceX operational mis ...

landing failure on 14 April 2015. The second JRTI vessel, using the ''Marmac 303'' barge hull, was converted during 2015 in a Louisiana shipyard. When the refit as an ASDS was complete, the barge transited the

Panama Canal The Panama Canal ( es, Canal de Panamá, link=no) is an artificial waterway in Panama that connects the Atlantic Ocean with the Pacific Ocean and divides North and South America. The canal cuts across the Isthmus of Panama and is a condui ...

in June 2015, carrying its wing extensions – the same ones originally built for the first ASDS built, JRTI on ''Marmac 330'') – as cargo on the deck because the ASDS, when complete, would be too wide to pass through the canal. The ship underwent a major refit in September 2019 to May 2020, first in Louisiana, and finished at Port Canaveral, including four new, much larger, positioning thrusters. The home port for the ''Marmac 303'' was initially the Port of Los Angeles (until in August 2019) at the Altana Sea marine research and business campus in

San Pedro, California San Pedro ( ; Spanish: "St. Peter") is a neighborhood within the City of Los Angeles, California. Formerly a separate city, it consolidated with Los Angeles in 1909. The Port of Los Angeles, a major international seaport, is partially located wi ...

's outer harbor. The landing platform and tender vessels began docking there in July 2015 in advance of the main construction of the AltaSea facilities. SpaceX announced that the ''Marmac 303'' would be the second ASDS to be named ''Just Read the Instructions'' in January 2016, shortly before its first use as a landing platform for Falcon 9 Flight 21. On 17 January 2016, ''JRTI'' was put to first use in an attempt to recover a Falcon 9 first-stage booster from the Jason-3 mission from

Vandenberg Space Launch Complex 4 Space Launch Complex 4 (SLC-4) is a launch and landing site at Vandenberg Space Force Base, California, U.S. It has two pads, both of which are used by SpaceX for Falcon 9, one for launch operations, and other as Landing Zone 4 (LZ-4) for Spac ...

. The booster successfully landed on the deck; however, a lockout collet failed to engage on one of the legs, causing the first stage to tip over, exploding on impact with the deck. On 14 January 2017, SpaceX launched Falcon 9 flight 29 from

and landed the first stage on the ''JRTI'', which was located about downrange in the

, making it the first successful landing in the Pacific. In August 2019, ''JRTI'' left the Port of Los Angeles to be towed to the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...

; it transited through the

. ''JRTI'' arrived in Morgan City, Louisiana in late August 2019 and stayed there until December 2019 then moved to

. ''JRTI'' is currently based at Port Canaveral and began operations in the Atlantic in June 2020, supporting the first time a Falcon 9 would land after a 5th use.

''A Shortfall of Gravitas''

A fourth ASDS, ''A Shortfall of Gravitas'' (''ASOG''), was announced in February 2018 and was originally planned to enter service in mid-2019. In October 2020, Elon Musk re-affirmed plans to build a ship of this name.Elon Musk on Twitter
New SpaceX droneship will be called "A Shortfall of Gravitas"
. In January 2021, ''Marmac 302'' was spotted at

Bollinger Bollinger () is a French Champagne house, a producer of sparkling wines from the Champagne region. They produce several labels of Champagne under the Bollinger name, including the vintage ''Vieilles Vignes Françaises, Grande Année'' and ''R.D. ...

Fourchon site. On 6 April 2021, ''NASASpaceFlight.com'' spotted the Octagrabber presumed to be for ''A Shortfall of Gravitas'' at the Cidco Road facility in

Cocoa Beach, Florida Cocoa Beach is a city in Brevard County, Florida, United States. The population was 11,539 at the 2018 United States Census. It is part of the Palm Bay-Melbourne-Titusville, Florida Metropolitan Statistical Area. History The first non-native ...

. It may have originated as an upgraded Octagrabber for ''Just Read The Instructions''. By mid April 2021, ''Marmac 302'' had scaffolding to prepare for construction, which was confirmed on 9 May 2021. It joined the East Coast fleet in July, after sending ''OCISLY'' to the West Coast in July 2021. On 9 July 2021, Elon Musk tweeted aerial footage of the completed drone ship in the Gulf of Mexico while undergoing its first sea-trials. According to him, this drone ship will not require a tug boat to be towed to the landing area. ''ASOG'' is used to support rocket launches from a base at

. After completing a sea trial in Port Fourchon, transiting over the Gulf of Mexico while being towed by Finn Falgout from its construction port, Port Fourchon to its recovery base, Port Canaveral, arriving at 16:47 UTC on 15 July 2021, and completing a number of sea trials, it successfully completed its first booster landing attempt for a Falcon 9 first-stage booster B1061.4 being used in CRS-23 mission at 300 km downrange in the

, becoming the first ASDS to land a first stage booster in its maiden landing attempt. ''ASOG'' is currently based at Port Canaveral to support east coast recovery operations.

Characteristics

The ASDS are

autonomous In developmental psychology and moral, political, and bioethical philosophy, autonomy, from , ''autonomos'', from αὐτο- ''auto-'' "self" and νόμος ''nomos'', "law", hence when combined understood to mean "one who gives oneself one's ow ...

vessels capable of precision positioning, originally stated to be within even under storm conditions, using GPS position information and four diesel-powered

azimuth thruster An azimuth thruster is a configuration of marine propellers placed in pods that can be rotated to any horizontal angle (azimuth), making a rudder unnecessary. These give ships better maneuverability than a fixed propeller and rudder system. Ty ...

s. In addition to the autonomous operating mode, the ships may also be telerobotically controlled. The azimuth thrusters are hydraulic propulsion outdrive units with modular diesel-hydraulic-drive power units manufactured by Thrustmaster, a marine equipment manufacturer in Texas. The returning first stage must not only land within the confines of the deck surface, but must also deal with ocean swells and GPS errors. SpaceX equips the ships with a variety of sensor and measurement technology to gather data on the booster returns and landing attempts, including

commercial off the shelf Commercial off-the-shelf or commercially available off-the-shelf (COTS) products are packaged or canned (ready-made) hardware or software, which are adapted aftermarket to the needs of the purchasing organization, rather than the commissioning of ...

GoPro cameras.. At the center of the ASDS landing pads is a circle that encloses the SpaceX stylized "X" in an X-marks-the-spot landing point.

Names

The ASDS have names that are the same as or similar to spaceships that appear in the

Culture series The ''Culture'' series is a science fiction series written by Scottish author Iain M. Banks and released from 1987 through to 2012. The stories centre on The Culture, a utopian, post-scarcity space society of humanoid aliens, and advanced su ...

of science fiction novels by Iain M. Banks.

''Just Read the Instructions'' (''Marmac 300'')

The landing platform of the upper deck of the first barge named ''Just Read the Instructions'' was , while the span of the

Falcon 9 v1.1 Falcon 9 v1.1 was the second version of SpaceX's Falcon 9 orbital launch vehicle. The rocket was developed in 2011–2013, made its maiden launch in September 2013, and its final flight in January 2016. The Falcon 9 rocket was fully designed ...

landing legs was .

''Of Course I Still Love You'' (''Marmac 304'')

''Of Course I Still Love You'' was built as a refit of the barge ''Marmac 304'' for landings in the Atlantic Ocean. Its homeport was

, Florida, from December 2015 to June 2021, after being ported for a year at the Port of Jacksonville during most of 2015. ''Of Course I Still Love You'' worked successfully as a landing platform after the Falcon 9 rocket brought astronauts to space on the crewed mission

Demo-2 Crew Dragon Demo-2 (officially Crew Demo-2, SpaceX Demo-2, or Demonstration Mission-2) was the first crewed test flight of the Crew Dragon spacecraft. The spacecraft, named '' Endeavour'', launched on 30 May 2020 on a Falcon 9 booster, and carr ...

on 30 May 2020. In June 2021, OCISLY was transported to the

to begin supporting launches on the west coast. On 8 July 2021, ''OCISLY'' was docked in Long Beach after transiting the Panama Canal.

''Just Read the Instructions'' (''Marmac 303'')

''Just Read the Instructions'', the second barge with that name, was built as a refit of the barge ''Marmac 303'' in 2015 for landings in the Pacific Ocean. Its homeport was in the Port of Los Angeles, California from 2015 to 2019 but in August 2019 it was moved to the Gulf of Mexico. In December 2019 it was moved to Cape Canaveral.

''A Shortfall of Gravitas'' (''Marmac 302'')

The fourth ASDS, named ''A Shortfall of Gravitas'', was mentioned by SpaceX in February 2018 and again in October 2020 to help support East Coast launches. In May 2021, conversion of ''Marmac 302'' into ''ASOG'' began and was expected to move to the East Coast for operation in the following months. ''A Shortfall of Gravitas'' underwent its first sea trials on 9 July 2021, and a short video of the ship underway was shared on Twitter by Elon Musk. After completing the sea trials, it was towed by Finn Falgout from its construction port, Port Fourchon, to its recovery base, Port Canaveral, arriving 15 July 2021.

Operation

A tug is used to bring the ASDS to its oceanic position, and a support ship stands by some distance away from the crewless ASDS. The vessels initially used on the East Coast were ''Elsbeth III'' (tug) and '' GO Quest'' (support). Following landing, technicians and engineers typically board the landing platform and secure the rocket's landing legs to lock the vehicle in place for transport back to

port A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as H ...

. The first stage is secured to the deck of the drone ship with steel hold-downs welded on to the feet of the landing legs. In June 2017, ''OCISLY'' started being deployed with a robot that drives under the rocket and grabs onto the hold-down clamps located on the outside of the Falcon 9's structure after landing. Fans call the robot "

Optimus Prime Optimus Prime, , is a fictional character in the ''Transformers'' franchise. The Transformers characters were developed for an American market after Hasbro representatives visited the 1983 Tokyo Toy Show. The characters were modified and the ...

" or " Roomba", the latter of which has been turned into a

backronym A backronym is an acronym formed from an already existing word by expanding its letters into the words of a phrase. Backronyms may be invented with either serious or humorous intent, or they may be a type of false etymology or folk etymology. The ...

for "remotely operated orientation and mass balance adjustment". Starting with the ''A Shortfall of Gravitas'' and ''Just Read The Instructions'' after it, these drone ships will not need to use a tug to bring the ASDS to the Falcon 9 landing zone, as they will now be fully autonomous. Later, A Shortfall of Gravitas droneship became the first ASDS that has an Automatic identification system (AIS) tracker, followed by another AIS tracker for Just Read The Instructions. This helps to track its voyage during recovery operations and especially when it becomes a fully autonomous droneship.

Vessel missions

The first

flight test Flight testing is a branch of aeronautical engineering that develops specialist equipment required for testing aircraft behaviour and systems. Instrumentation systems are developed using proprietary transducers and data acquisition systems. D ...

was 10 January 2015, when SpaceX conducted a controlled-descent

to land the first stage of Falcon 9 Flight 14 on a solid surface after it was used to loft a contracted payload toward Earth orbit. SpaceX projected prior to the first landing attempt that the

likelihood The likelihood function (often simply called the likelihood) represents the probability of random variable realizations conditional on particular values of the statistical parameters. Thus, when evaluated on a given sample, the likelihood functi ...

of successfully landing on the platform would be 50% or less. The landings went from being landing tests towards being routine parts of missions.

Autonomous spaceport drone ship (ASDS) Statistics

ASDS Usage

Booster landings

Mission Details

Notes

References

External links

Thrustmaster drive unit specifications
{{SpaceX SpaceX maritime vessels Autonomous ships Robotics in the United States Barges of the United States Experimental ships of the United States Floating launch vehicle operations platform Maritime vessels related to spaceflight Ships built in Louisiana SpaceX related lists