SpaceX CRS-21, also known as SpX-21, was a Commercial Resupply Service mission to the

International Space Station The International Space Station (ISS) is the largest modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA ...

which launched on 6 December 2020. The mission was contracted by

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, succeeding t ...

and was flown by

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 of ...

using a Cargo Dragon 2. This was the first flight for SpaceX under NASA's CRS Phase 2 contract awarded in January 2016. This was also the first Cargo Dragon of the new Dragon 2 variant, as well as the first Cargo Dragon flight that was docked at the same time as a Crew Dragon spacecraft (

SpaceX Crew-1 SpaceX Crew-1 (was also known as USCV-1 or simply Crew-1) was the first operational crewed flight of a Crew Dragon spacecraft, and the maiden flight of the Crew Dragon ''Resilience'' spacecraft. It was also the second crewed orbital flight l ...

). This mission used Booster B1058.4, becoming the first NASA mission to reuse a booster previously used on a non-NASA mission. This was also first time SpaceX launched a NASA payload on a booster with more than one previous flight.

Cargo Dragon

SpaceX plans to reuse the Cargo Dragons up to five times. It was launched without seats, cockpit controls, the life support system required to sustain astronauts in space and

SuperDraco SuperDraco is a hypergolic propellant rocket engine designed and built by SpaceX. It is part of the SpaceX Draco family of rocket engines. A redundant array of eight SuperDraco engines provides fault-tolerant propulsion for use as a launch es ...

abort engines.

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 ...

improves on Dragon 1 in several ways, including lessened refurbishment time, leading to shorter periods between flights. While CRS-21 was for a standard 30 days mission, the most recent Flight Planning Integration Panel (FPIP) document indicates that beginning with CRS-23, SpaceX cargo missions will begin to stretch out to 60 days and beyond. Sarah Walker, director of Dragon mission management at SpaceX, said "the new Cargo Dragon can stay at the space station for up to 75 days, more than twice as long as the first-generation Dragon spacecraft". With this mission, this was the first time that two Dragon capsules were docked at the ISS at the same time. Beginning with the CRS-21 mission, the new Dragon Cargo capsules splash down under parachutes off the coast of Florida in either 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 ...

or the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, 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 ...

. This NASA preference was added to CRS-2 awards.

Mission

Expedition 64 - Status with the new NanoRacks Bishop airlock

Timeline

T+00:00: Liftoff
T+01:18: Maximum aerodynamic pressure
T+02:30: First stage main engine cutoff (MECO)
T+02:34: Stage separation
T+02:41: Second stage engine start
T+06:37: First stage entry burn begins
T+08:38: Second stage engine cutoff (SECO)
T+08:38: First stage landing on drone ship
T+11:49: Dragon separation
T+12:35: Dragon nose cone open sequence begins

Payload

NASA contracted for the CRS-21 mission from SpaceX and therefore determines the primary payload, date of launch, and

orbital parameters Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are considered in two-body systems using a Kepler orbit. There are many different ways to mathematically describe the same ...

for the Cargo Dragon. The CRS-21 mission carries of cargo to ISS. * Science investigations: * Vehicle hardware: * Crew supplies: * Spacewalk equipment: * Computer resources: * Russian hardware: * External payload (Nanoracks Bishop Airlock): KSC-20200929-PH GEB02 0028

Nanoracks Bishop Airlock The Nanoracks Bishop Airlock is a commercially-funded airlock module launched to the International Space Station on SpaceX CRS-21 on 6 December 2020. It was berthed to the ''Tranquility'' module on 19 December 2020 by the Canadarm2. The modu ...

, formerly known as Bishop Airlock Module, is a payload airlock attached to the ''Tranquility'' module of the ISS, commercially developed and operated by

Nanoracks Nanoracks LLC is a private in-space services companywhich builds space hardware and in-space repurposing tools.The company also facilitates experiments and launches of CubeSats to Low Earth Orbit. Nanoracks's main office is in Houston, Texa ...

. The Bishop Airlock provides five times the satellite deployment volume previously available, when the Japanese Kibō airlock served that role alone. Nanoracks is the prime contractor, with

Thales Alenia Space Thales Alenia Space () is a Franco-Italian aerospace manufacturer. A joint venture between the French technology corporation Thales Group (67%) and Italian defense conglomerate Leonardo (33%), the company is the largest satellite manufactur ...

manufacturing the pressurized shell and

Boeing The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and p ...

providing the berthing mechanism. It is the second commercial module of the ISS, after the

Bigelow Expandable Activity Module The Bigelow Expandable Activity Module (BEAM) is an experimental expandable space station module developed by Bigelow Aerospace, under contract to NASA, for testing as a temporary module on the International Space Station (ISS) from 2016 to ...

(BEAM), which was attached to the ISS in April 2016 and is expected to stay at the ISS until at least 2028. The Bishop Airlock began construction in 2015, and was berthed to ''Tranquility'' on 19 December 2020 by the Canadarm2.

Experiments

BioAsteroid is an experiment designed to test the infrastructure and tools needed for asteroid, lunar, and Martian rock mining. It will mine basalt from those bodies for exploration when humans eventually land on them. Hemocue is a test of the system for white blood cell testing on the Moon and Mars. The systems were developed under Earth's gravity, and still need to be tested in zero-g's. The Brain Organoid experiment is a continuation of the first Brain Organoid experiment. Its goal is to validate the first round of experiments and to continue the research recorded during those first tests. The program studies the early developed human brain, its movements in microgravity, and can help address and create better models of neurodegenerative disorders. Cardinal Heart is a continuation of a previous experiment. This experiment will study cardiomyocytes in human heart tissue and its reaction to a zero-g environment. NASA Astronaut

Kate Rubins Kate name may refer to: People and fictional characters * Kate (given name), a list of people and fictional characters with the given name or nickname * Gyula Káté (born 1982), Hungarian amateur boxer * Lauren Kate (born 1981), American autho ...

was present for the experiment on station a few years ago, and she said that, paraphrased, few things on station make her gasp, but this is one thing that does. Subsa-Brains studies the effects of micrometeorites and space junk and the damage they can cause, as well as the process to repair the tissue, called brazing, and if it still works in a zero-gravity environment. Three-Dimensional Microbial Monitoring (3DMM) is a project that aims to construct a three-dimensional map of bacteria and metabolites that are present at various locations throughout the ISS, and determine how the spaceflight environment affects the various species identified. Monoclonal Crystal Research in Microgravity (MCRM) is a protein crystallization experiment by the American pharmaceutical company Bristol Myers Squibb. NASA astronauts will study the crystallization of monoclonal antibodies in space, with the aim of improving drug formulation and delivery for patients on Earth. Monoclonal antibodies are lab-created proteins designed to interact with specific targets, called

antigen In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune respons ...

s. Monoclonal antibodies are used in the treatment of numerous diseases, including cancer. Rodent Research-23 (RR-23), will study the effects of spaceflight on the eyes, specifically on the structure and function of the arteries, veins, and lymphatic vessels that are needed to maintain vision. Student Spaceflight Experiments Program: The Student Spaceflight Experiments Program (SSEP) has 27 experiments manifested as part of Mission 14A. The CRS-21 pressurized capsule carries a variety of other research including studies on how space conditions affect the interaction between microbes and minerals.

Returning hardware

Beginning with returning capsules or lifting bodies under the CRS-2 contract, NASA reports major hardware (failed or expended hardware for diagnostic assessment, refurbishment, repair, or no longer needed) returning from the International Space Station. The SpaceX CRS-21 mission ended on 14 January 2021 with re-entry into

Earth's atmosphere The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing fo ...

and splash down near the western coast of

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 ...

with of return cargo. This cargo included: Treadmill Data Avionics Unit: Failed avionics unit that supports the treadmill, a critical item returning to the ground following the on-orbit replacement with a good spare. Carbon Dioxide Removal Assembly (CDRA) Air Selector Valve: Critical degraded valve returning for repair and refurbishment to support the carbon dioxide removal capability on-orbit. Nitrogen Oxygen Recharge System (NORS) Tank: Depressurized tank capable of flying oxygen or nitrogen, and will be utilized for future on-orbit demand in 2021. Rodent Research Habitats and Transporters: Live rodents from the Rodent Research-23 (RR-23) mission and used habitats and transporters that support future research missions and analysis. Minus Eighty Laboratory Freezer for ISS (MELFI) Electronics Unit: Failed cold stowage item requiring ground repair to enable future cold stowage missions. Thermal Amine Bulk Water Save Valve: Failed valve that supports efficient usage of the Thermal Amine system returning to ground for repair, will help inform robustness of similar valve design on Orion capsule.

Undocking and return

Before the heading for re-entry, the automated cargo capsule undocked from the

(ISS) on 12 January 2021 at 14:05 UTC. The undocking and splashdown completed the first cargo mission of SpaceX's Dragon 2 spacecraft. SpaceX recovery teams were on standby for the parachute-assisted splashdown on 14 January 2021 at 01:26 UTC in the

, at west of

Tampa, Florida Tampa () is a city on the Gulf Coast of the United States, Gulf Coast of the U.S. state of Florida. The city's borders include the north shore of Tampa Bay and the east shore of Old Tampa Bay. Tampa is the largest city in the Tampa Bay area and ...

. The Dragon returned to

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

with of cargo, according to

References

External links

NASA

SpaceX official page for the Dragon spacecraft

Nanoracks Bishop Airlock

GNSS Remote Sensing aboard the ISS
{{Orbital launches in 2020 SpaceX Dragon 2 Spacecraft launched in 2020 Spacecraft which reentered in 2021 SpaceX payloads contracted by NASA Supply vehicles for the International Space Station 2020 in the United States