Crew-2 mission on SpaceX’s Crew Dragon spacecraft
Launch: SpaceX launched a Crew Dragon spacecraft carrying four astronauts from three nations April 23 as the commercial crew program moves firmly into operations. 1)
- The Falcon 9 rocket lifted off from Launch Complex 39A here at 9:49 UTC 23 April 2021 (5:49 a.m. EDT) on the Crew-2 mission. The Crew Dragon spacecraft separated from the Falcon 9 upper stage 12 minutes after liftoff, while the Falcon 9 first stage landed on a droneship in the Atlantic.
Figure 1: A SpaceX Falcon 9 lifts off on the Crew-2 mission 23 April 2o21 (image credit: NASA, Aubrey Gemignani)
- On board the Crew Dragon are NASA astronauts Shane Kimbrough and Megan McArthur, European Space Agency astronaut Thomas Pesquet and Japan Aerospace Exploration Agency astronaut Akihiko Hoshide. Their spacecraft is scheduled to dock with the International Space Station at about 5:10 a.m. EDT on 24 April.
- The mission is the third crewed flight of the Crew Dragon in less than a year, after the Demo-2 mission in May 2020 and Crew-1 mission in November. The Crew-1 spacecraft is still at the ISS, and it will return with NASA astronauts Michael Hopkins, Victor Glover and Shannon Walker and JAXA astronaut Soichi Noguchi April 28.
- Leading up to the launch, NASA officials said that, after a decade of development, the commercial crew program — or, at least, SpaceX’s vehicle in that program — had clearly moved into operations. “It’s very, very exciting to be in this operational cadence,” said Kathy Lueders, NASA associate administrator for human exploration and operations, during an April 15 press conference after the flight readiness review for the Crew-2 mission, which also reviewed plans to return Crew-1 to Earth.
- Kimbrough, the commander of Crew-2, said this mission was the first to follow the streamlined training flow that future missions will use. “We’re the first ones to have gone through what we hope to be the templated flows for future crews,” he said at an April 17 press conference.
- That revised training program, he said, combines training on the Crew Dragon spacecraft with that for the ISS. “It’s a little less than a year of training, where the crews in front of us had several years of training. Instead of being more developmental, it’s more operational now.”
- “This has been a pretty amazing time with DM-2 and then the Crew-1 launch, and now we’re getting ready for Crew-2,” Bill Gerstenmaier, a former NASA associate administrator for human exploration and operations who is now a SpaceX vice president, said at the April 15 briefing.
- He cautioned, though, that just because the commercial crew program is moving into a regular cadence of missions, it doesn’t mean crewed missions are routine. “We’re still beginning in this process. We need to not get lulled into thinking that this is fully operational and we’re ready to just continue this in an easy manner,” he said. “This is still very much a learning experience for us.”
- That learning experience extends to this flight, which marks the first use of both a previously flown Falcon 9 first stage and Crew Dragon spacecraft on a crewed mission. “We had to do an extensive amount of work to look at both the Dragon for use and also the F9,” Steve Stich, NASA commercial crew program manager, said at that April 15 press conference.
- That review both examined the vehicles to ensure they met requirements as well as make a number of upgrades to the Crew Dragon spacecraft based on the experience from the Demo-2 mission. Those changes included upgrades to the SuperDraco thrusters and other aspects of the propulsion system used for aborts and improving the spacecraft’s batteries.
- “It was a series of upgrades to improve safety,” he said, “and having to make sure the structures, the component lifetimes were all within the certification and the qualification of those components.”
- While the missions are becoming more operational, it is still early enough in the program for astronauts to develop new traditions. “Even though there’s some heritage from previous vehicles on the U.S. side, we still get to create some new traditions, which is really cool,” said Pesquet.
- One thing the Crew-2 astronauts did that could become such a tradition, he said, is writing their initial in the soot on the Falcon 9 booster that will launch them. That soot is from the booster’s first launch, of the Crew-1 mission last November. “I don’t know if this is going to stick, but I found it really cool.”
- The best tradition, though, may be a safe and successful flight. “My takeaway from where I sit right now is that we’ve just got to be really careful,” Gerstenmaier said. “We’re still learning. This is still just the beginning of how we move forward into this new commercial area.”
- Thomas Pesquet’s second mission to the International Space Station is called Alpha. This is after Alpha Centauri, the closest stellar system to Earth, following the French tradition to name space missions after stars or constellations. 2)
• April 21, 2021: NASA’s SpaceX Crew-2 mission is set to launch four astronauts to the International Space Station aboard a SpaceX Crew Dragon on Friday, April 23. The four include NASA astronauts Shane Kimbrough and Megan McArthur and, a first for the Commercial Crew Program, two international partners, Japan Aerospace Exploration Agency (JAXA) astronaut Akihiko Hoshide and ESA (European Space Agency) astronaut Thomas Pesquet. 3)
- The Crew-2 astronauts will join the other members of Expedition 65, NASA astronaut Mark Vande Hei and cosmonauts Oleg Novitskiy and Pyotr Dubrov of Roscosmos, for a six-month mission conducting science experiments in low-Earth orbit. An important scientific focus on this expedition is continuing a series of Tissue Chips in Space studies. Tissue chips are small models of human organs containing multiple cell types that behave much the same as they do in the body.
- These chips may make it possible to identify safe and effective therapeutics – drugs or vaccines – much more quickly than the standard process. In addition, many changes occurring in the human body during spaceflight resemble the onset and progression of aging and diseases on Earth but occur much more quickly in microgravity. Scientists use specialized tissue chips in space to model diseases that affect specific organs in the human body but that might take months or years to develop on Earth.
- Tissue chips are one aspect of tissue engineering, which uses a combination of cells, engineering, and materials to restore, maintain, improve, or replace biological tissues. Tissues engineered on Earth require some sort of scaffold on which to grow and can only reach a thickness of at most 1 cm, or just over a quarter inch. But in microgravity, rather than growing in a flat layer, cells can grow into three dimensions that closely mimic tissues in the body.
- “We know that cells communicate with each other and that this communication is critical for proper functioning,” says Liz Warren, senior program director at the ISS U.S. National Laboratory. “We don’t fully understand why, but in microgravity, cell-to-cell communication works differently than it does in a cell culture flask on Earth. Cells also aggregate or gather together differently in microgravity. These features allow cells to behave more like they do when inside the body. Thus, microgravity appears to provide a unique opportunity for tissue engineering.”
- A partnership between the ISS National Lab and the National Institutes of Health’s National Center for Advancing Translational Sciences (NCATS) has sent tissue chips to the space station to analyze the effects of microgravity on human health and translate that to improvements on Earth. Investigations are using tissue chips to study aging of the immune system, lung immune response, musculoskeletal disease, kidney function, muscle loss or sarcopenia, and more.
- All tissue chip investigations are assigned two flights, Warren explains, with a number of these experiments launching for the second time during Expedition 65. “The first flight is a validation of the system. The second flight is generally intended to test a therapeutic or therapeutics.”
- Another important element of Crew-2’s mission is updating the station’s solar power system by installing the ISS Roll-out Solar Array (iROSA) – compact panels that roll open like a huge yoga mat. The technology development dates back to 2009, benefiting from dozens of NASA Small Business Innovation Research awards and later ground demonstrations. In 2017, the basic design underwent testing on the space station to determine its strength and durability. The Expedition 65 crew is scheduled to begin preparations for supplementing the station’s existing rigid panels this summer with the first pair of six new arrays.
Figure 2: NASA and Boeing workers lift solar arrays into flight support equipment on April 2, 2021, in the Space Station Processing Facility at NASA’s Kennedy Space Center in Florida. The 63- by- 20-foot solar arrays will launch to the International Space Station later this year (image credit: NASA/KSC)
- One research investigation flying aboard Crew Dragon with Crew-2, CHIME, studies possible causes for suppressed immune response in microgravity. Microgravity may cause changes to the human immune system, a possible concern for long-term space travel. The CHIME investigation could help identify potential causes of immune system dysfunction and lead to ways to prevent or counteract it, helping space travelers as well as those with compromised immune systems on Earth.
- Crew members remain incredibly busy between maintenance and upgrades to the station itself inside and out, daily activities to keep themselves healthy, and a full slate of scientific research – the station’s primary purpose. Adding more crew members aboard the microgravity laboratory increases the time available for scientific activities. The November 2020 addition of the Crew-1 team, NASA astronauts Michael Hopkins, Victor Glover, and Shannon Walker and JAXA astronaut Soichi Noguchi, to the Expedition 64 crew of cosmonauts Sergey Ryzhikov and Sergey Kud-Sverchkov and NASA astronaut Kate Rubins more than doubled crew hours spent on scientific research and support activities.
- Crew-2’s Earth Day launch seems fitting, given that the space station contributes significantly to climate research. Expedition 65 astronauts join many others before them in recording our planet through the Crew Earth Observations (CEO) project. Overall, crew members have taken more than 1.5 million images of Earth, contributing to scientific research such as studies on artificial lighting at night, algal blooms, and the breakdown of Antarctic ice shelves.
- When the members of Crew-2 return to Earth in the fall, they will have upped that image tally as well as the total number of hours spent on scientific activities in space. With astronauts already chosen for Crew-3 and Crew-4, the orbiting lab continues to rack up impressive results.
• April 16, 2021: NASA managers approved plans to launch a SpaceX commercial crew mission to the International Space Station next week, pending the resolution of one minor issue with the Falcon 9 rocket. 4)
Figure 3: The Crew Dragon spacecraft that will fly the Crew-2 mission is prepared for its April 22 launch (image credit: SpaceX)
- NASA officials said April 15 that, after the completion of a flight readiness review, they approved plans for the launch April 22 of the Crew-2 mission, which will transport American, European and Japanese astronauts to the station on a Crew Dragon spacecraft.
- “The flight readiness review was very successful. We only had one exception, which needs to be cleared up in the next few days,” said Kathy Lueders, NASA associate administrator for human exploration and operations, during a press conference after the review.
- That exception involves an issue with loading liquid oxygen into the first stage of the Falcon 9 that results in more liquid oxygen being in the tank than expected. The error is relatively small: Bill Gerstenmaier, the longtime NASA official who is now a vice president for SpaceX, said the level of liquid oxygen in the tank was no more than about 10 centimeters higher than expected.
- He said SpaceX discovered it during testing of a Falcon 9 first stage at the company’s McGregor, Texas, facility, when weather interrupted the usual loading process. “That gave us some insight that we don’t typically get, and we got to see that the amount of oxidizer that we had loaded into the tank was a little bit different than what we had analyzed it to be,” he said.
- SpaceX will take the time to analyze the loading error, which Gerstenmaier said was common to all Falcon 9 rockets, to ensure the safety of the upcoming crewed launch. “I think in a normal program, this amount of difference wouldn’t matter to anyone, but in our world, we’re going to take the extra step and go review it, look at the consequences and what happens worst-case,” he said.
- If that issue is resolved, SpaceX will go ahead with a static-fire test of the Falcon 9 first stage early April 17 at Kennedy Space Center’s Launch Complex 39A. The launch is scheduled for 6:11 a.m. Eastern April 22, with a backup launch date a day later. If the mission is delayed beyond April 23, the next opportunity to launch would be April 26.
- Other preparations for the launch are proceeding normally. The astronauts that will fly the Crew-2 mission — NASA’s Shane Kimbrough and Megan McArthur, ESA’s Thomas Pesquet and JAXA’s Akihiko Hoshide — will arrive at KSC April 16 and go through a “dry dress rehearsal” of launch preparations two days later.
- They will fly both a spacecraft and rocket that have been used before. The Crew Dragon spacecraft, called Endeavour, launched on the Demo-2 mission in May 2020, the first crewed Crew Dragon mission, while the Falcon 9 first stage previously launched the Crew-1 mission in November 2020.
- “We had to do an extensive amount of work” to confirm both the Crew Dragon and Falcon 9 booster were safe for reuse on a crewed mission, said Steve Stich, manager of NASA’s commercial crew program. That also evaluated a number of upgrades to the vehicle, such as an improved battery system and changes to the abort thrusters that allow them to use more propellant and thus improve their performance.
- “It was a series of upgrades to improve safety,” he said, “and having to make sure the structures, the component lifetimes were all within the certification and the qualification of those components.”
- If Crew-2 does launch April 22, it will dock with the ISS at about 5:30 a.m. Eastern April 23. The Crew-1 spacecraft currently at the station would depart the station on the morning of April 28, splashing down at 12:40 p.m. Eastern that day in the Gulf of Mexico off the coast from Tallahassee, Florida.
- Stich said NASA was working with the U.S. Coast Guard to prevent a repeat of the Crew-1 splashdown in August 2020, when dozens of private boaters swarmed the capsule after splashdown. More Coast Guard vessels will patrol the splashdown zone to keep other ships at a safe distance. “We don’t anticipate having that problem again.”
• March 5, 2021: This is the second crew rotation flight to the ISS with astronauts on the Crew Dragon spacecraft and the first launch with two international partners as part of the agency’s Commercial Crew Program. 5)
- The launch, on a Falcon 9 rocket, is targeted for no earlier than Thursday, April 22, from Launch Complex 39A at NASA’s Kennedy Space Center in Florida.
- NASA’s SpaceX Crew-2 mission will carry NASA astronauts Shane Kimbrough and Megan McArthur – who will serve as the mission’s spacecraft commander and pilot, respectively – along with JAXA (Japan Aerospace Exploration Agency) astronaut Akihiko Hoshide and ESA (European Space Agency) astronaut Thomas Pesquet, who will serve as mission specialists.
- After successfully docking at the space station, the astronauts of Crew-2 will join the Expedition 65 crew aboard the orbital outpost, including the Crew-1 astronauts still aboard. The Crew-1 astronauts are targeted for return in late April or early May.
- NASA’s Commercial Crew Program is working with the American aerospace industry through a public-private partnership to launch astronauts on American rockets and spacecraft from American soil. The goal of the program is to provide safe, reliable, and cost-effective transportation to and from the space station, which will allow for additional research time and will increase the opportunity for discovery aboard humanity’s testbed for exploration. The space station remains the springboard to NASA's next great leap in space exploration, including future missions to the Moon and eventually to Mars.
Figure 4: Pictured from left are NASA astronaut Megan McArthur, ESA (European Space Agency) astronaut Thomas Pesquet, JAXA (Japan Aerospace Exploration Agency) astronaut Akihiko Hoshide, and NASA astronaut Shane Kimbrough (image credit: NASA)
• NASA officials said March 1, 2021, that the next SpaceX commercial crew mission to the International Space Station remains on schedule for late April, but that a Boeing uncrewed test flight is facing further delays. 6)
The Crew-2 mission, a flight of SpaceX’s Crew Dragon spacecraft carrying astronauts from NASA,ESA (European Space Agency) and JAXA (Japan Aerospace Exploration Agency) to the station, remains on track for a launch no earlier than April 20, agency officials said at a briefing.
The actual launch date may shift by a few days “to more optimize some of the orbital mechanics and the launch opportunities,” said Steve Stich, manager of NASA’s commercial crew program. The agency is trying to fit the mission in during a window between the mid-April departure of the Soyuz MS-17 spacecraft and a “beta cutout” in May when sun angles restrict ISS activities.
That schedule also has to accommodate the return of the Crew-1 mission on the Crew Dragon currently docked to the station. Stich said the goal is to have that spacecraft return to Earth by May 9 to avoid “dark landing opportunities” for the spacecraft’s splashdown.
Neither NASA nor SpaceX see any major challenges to launching in late April, even after the shutdown of a Merlin engine on a Feb. 15 Falcon 9 launch that prevented the booster from landing. “Everybody is on track and ready for an April 20 launch readiness date,” Benji Reed, senior director of human spaceflight programs at SpaceX, said at the briefing.
The Crew-2 mission will be the third Crew Dragon flight to carry astronauts, but the first such spacecraft to be reused. The Crew Dragon capsule for Crew-2 previously flew the Demo-2 mission last year, and workers have spent the last several months refurbishing it for the upcoming flight.
SpaceX has been working with NASA on the refurbishment process, determining what components need to be replaced to ensure crew safety and what can be kept. “I can happily say that the vast majority of the vehicle is flight-proven,” Reed said. Some valves and parts of the thermal protection system are being changed, he said, along with parachutes that are replaced after every flight. “Otherwise, it’s really the same vehicle that’s very carefully inspected, carefully prepared and refurbished as needed, and ready to fly.”
SpaceX has also “beefed up” the structure of the spacecraft to improve the acceptable wind speeds and wave heights for splashdown, thus expanding the landing opportunities. “This is one of the most important updates that we’ve done on this Dragon,” he said.
Stich added the spacecraft has improved pad abort performance in the form of additional propellant for the SuperDraco thrusters, which also improves launch constraints by allowing launches when there are stronger onshore winds. “I really look at this flight as an abort enhancement flight,” he said.
The Crew-2 mission was scheduled to be the third crew-capable spacecraft to visit the ISS in April. It will be preceded by the Soyuz MS-18 spacecraft, set for launch April 9.
NASA had scheduled the launch of Boeing’s CST-100 Starliner commercial crew vehicle on the uncrewed Orbital Flight Test (OFT) 2 mission for April 2. That mission will be a reflight of the original, flawed OFT mission in December 2019 that was unable to dock with the station because of software problems.
It’s now unlikely, though, that the mission, recently delayed from late March, will be ready to launch in early April. “We are going to move off of 4/2,” Stich said. Preparations for the mission are about two weeks behind schedule, he said, in part because of winter weather and associated power outages in the Houston area that delayed software testing for the spacecraft by a week.
It’s unclear when the OFT-2 can take place because of the upcoming Soyuz and Crew-2 missions, and then availability on the Eastern Range at Cape Canaveral for the Atlas 5 launch of the mission. “It’s a very busy timeframe on the space station,” Stich said. “And then it’s a busy time on the range, so we’re working hand-in-hand with Boeing to figure out when that launch date will be. We’ll have to stand by for further developments on exactly when that flight will fly.”
Crew-2 arrives at ISS
• April 24, 2021: The SpaceX Crew Dragon spacecraft arrived at the International Space Station April 24, less than 24 hours after its launch from Florida, giving the station its largest crew in a decade. 7)
- The Crew Dragon spacecraft Endeavour, which launched from the Kennedy Space Center April 23, docked with the station’s Harmony module at 5:08 a.m. EDT. The four Crew-2 astronauts joined their seven colleagues on the station about two and a half hours later.
Figure 5: The four astronauts on the Crew-2 mission, in black shirts, join their colleagues on the International Space Station in ceremony just after the Crew Dragon Endeavour's arrival at the station April 24 (image credit: NASA TV)
- Endeavour, which also flew the Demo-2 mission to the station last summer, had a largely trouble-free flight to the ISS. The only issue was external to the spacecraft: controllers asked the crew to get back into their suits and close their visors several hours after launch as a precaution when a piece of space debris was projected to pass close to the spacecraft. The debris passed the spacecraft around 1:45 p.m. EDT April 23 without incident, and the Crew Dragon did not maneuver to avoid the object, which NASA did not identify.
- “It is awesome to see the 11 of you on station,” Steve Jurczyk, NASA acting administrator, said in a brief ceremony shortly after the hatches opened. “I’m really excited this for this new era for ISS.”
- With the arrival of Crew-2, the station has 11 people on board for the first time since the STS-134 shuttle mission in May 2011, when the five people on that mission joined the six people on the station who arrived on two Soyuz spacecraft. Here, two Crew Dragon spacecraft transported eight astronauts to the station while a Soyuz transported the other three.
- “There’s a number of things you have to do” to support that additional crew, said Joel Montalbano, NASA ISS program manager, at an April 20 briefing about the Crew-2 mission. That includes additional consumables and increasing the capability of the station’s life support systems, as well as temporary sleeping arrangements for the additional astronauts.
- That expanded crew size is temporary, as the Crew Dragon Resilience spacecraft will return the four Crew-1 astronauts to Earth on April 28. The spacecraft will undock at 7:05 a.m. EDT and splash down in the Gulf of Mexico south of Tallahassee, Florida, at 12:40 p.m. EDT.
1) Jeff Foust, ”SpaceX launches NASA Crew-2 mission,” SpaceNews, 23 April 2021, URL: https://spacenews.com/spacex-launches-nasa-crew-2-mission/
2) ”Mission Alpha liftoff,” ESA Science & Exploration, 23 April 2021, URL: https://www.esa.int/ESA_Multimedia/Videos/2021/04/Mission_Alpha_liftoff
Melissa Gaskill, ”Crew-2 Astronauts Head to Space Station to
Conduct Microgravity Science,” NASA, 21 April 2021, URL: https://www.nasa.gov/mission_pages/station
4) Jeff Foust, ”NASA approves plans for Crew-2 launch,” SpaceNews, 16 April 2021, URL: https://spacenews.com/nasa-approves-plans-for-crew-2-launch/
5) ”NASA, SpaceX Invite Media to Next Commercial Crew Launch,” NASA Press Release, 5 March 2021, URL: https://www.nasa.gov/press-release/nasa-spacex-invite-media-to-next-commercial-crew-launch
6) Jeff Foust, ”Crew-2 on schedule for April launch while next Starliner flight delayed,” SpaceNews, 2 March 2021, URL: https://spacenews.com/crew-2-on-schedule-for-april-launch-while-next-starliner-flight-delayed/
The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: ”Observation of the Earth and Its Environment: Survey of Missions and Sensors” (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (firstname.lastname@example.org).