Dragon to perform first 360-degree space station flyby from Shuttle – Spaceflight Now

SpaceX’s Crew Dragon Endeavor spacecraft glides towards docking at the International Space Station on April 24. Credit: NASA

Four astronauts wrapping up an almost 200-day orbiting expedition floated in their SpaceX Crew Dragon capsule to the International Space Station on Monday, hours before the ship was supposed to undock and complete a 360-degree loop around the current complex. of road. back to earth.

NASA Commander Shane Kimbrough, Pilot Megan McArthur, Japanese Astronaut Akihiko Hoshide and European Space Agency Mission Specialist Thomas Pesquet boarded their Crew Dragon spacecraft and closed a hatch leading to the space station at 12:12 p.m. EST (1712 GMT).

The astronauts planned to don their black and white SpaceX pressure suits and sit down, perform leak checks and prepare for undocking at 2:05 p.m. EST (1905 GMT) from an overhead port, or oriented up, on Space Station Harmony. module.

Flying on autopilot, the Crew Dragon Endeavor spacecraft will retreat to a distance of over 660 feet (200 meters) above the space station. Next, the capsule will fire its Draco thrusters to begin a flyby of the space station, starting above the outpost, then moving to positions behind, below, and in front of the complex.

The flyover maneuver will allow astronauts to photograph the exterior of the 450-ton space station complex as it rises more than 400 kilometers above the planet. This is the first time that a crewed spacecraft has performed a 360-degree flight over the station since the Space Shuttle retired in 2011.

The Russian Soyuz spacecraft carried out partial overflights of the space station.

The Dragon’s ability to perform an overflight is one of the latest NASA requirements for SpaceX’s crew capsule, which has yet to be tested in orbit.

“This will be the first time that Dragon will fly over … towards the Russian segment of the space station,” said Nicole Jordan, head of the spacecraft office for NASA’s commercial crew program. “So although they have fully modeled all of the different features of the station and we have very high confidence that the Dragon navigation system will know where it is at all times, this is a first step,” so it’s probably a bit of an increase in risk.

“If Dragon loses its navigation filter and becomes non-convergent, it could abort, so we’re ready for that. This has all been certified and reviewed, and it will be really interesting to see this operation and be able to get the first images of the station in a flyby from the time of the shuttle, ”Jordan told Spaceflight Now in an interview. .

As the astronauts rise from their seats to point the cameras out of Dragon’s front window, the capsule’s external cameras will record video of the space station throughout the maneuver, although the video will not be broadcast live. unless the spacecraft is above the SpaceX ground stations.

Approximately 90 minutes after the start of the overflight, the Crew Dragon spacecraft will activate its Draco thrusters to exit the vicinity of the space station, setting the stage for a 16-minute burn with the rocket jets from the bulkhead before the capsule departing. 9:41 p.m. EST (0241 GMT).

This diagram illustrates the flyover maneuver of the Crew Dragon spacecraft. Credit: NASA

Approximately five minutes before the brake burn begins, Crew Dragon Endeavor will drop its disposable trunk section, which will remain in orbit. The drag of Earth’s rarefied upper atmosphere will gradually lower the trunk’s altitude until it re-enters uncontrollably and burns, an event expected in a few weeks.

The reusable crew module containing Kimbrough, McArthur, Hoshide and Pesquet will be engaged to reenter after the desorbit burns, targeting a water landing in the Gulf of Mexico off Pensacola, Florida.

A SpaceX recovery ship is waiting near the landing zone to hoist the capsule out of the water. Once the Dragon spaceship is on the deck of the recovery ship, the teams will open the hatch and help the four crew members exit the capsule.

Medical stretchers will be available for astronauts, who have not been subjected to the effects of gravity since their launch on April 23 from NASA’s Kennedy Space Center in Florida.

The landing will be the fourth time that a SpaceX crew capsule has returned to Earth with crew members on board, and it will complete Crew Dragon’s second operational flight – known as Crew-2 – to the station. space under a multi-billion dollar contract with NASA. .

NASA and SpaceX have delayed the undocking and return to Earth of the Crew Dragon from last week in response to the delayed launch of a new team of astronauts on the Crew-3 mission. This launch was slated for Oct. 31 atop a Falcon 9 rocket, but high winds in the abandonment areas off the Dragon and a minor medical issue with one of Crew-3’s astronauts forced those in charge delay the flight.

A view of the International Space Station captured on September 28 by a cosmonaut during a partial flyby maneuver by the Soyuz MS-18 spacecraft. Credit: Roscosmos

NASA officials decided to swap the crew rotation order and bring the Crew-2 astronauts home before launching the Crew-3 mission. The change eliminated a planned in-orbit transfer between astronauts Crew-2 and Crew-3.

Crew-3 is now scheduled to launch at 9:03 p.m. EST (0203 GMT Thursday) on Wednesday from pad 39A at Kennedy Space Center. The Falcon 9 rocket from the Crew-3 mission and the Crew Dragon Endurance space capsule remained vertical on the launch pad during the delay.

During their eight-hour transit between the space station and the surface of the Gulf of Mexico, astronauts aboard the Crew Dragon Endeavor spacecraft will not be able to use the capsule toilet system. SpaceX discovered a urine leak encountered during the three-day all-civilian Inspiration4 flight aboard the Crew Dragon Resilience spacecraft, and inspections of the Endeavor capsule at the space station revealed that there was also a leak in the astronaut waste system.

NASA says astronauts will wear absorbent underwear instead of having toilet access. Astronauts on the Crew-3 mission slated for launch on Wednesday will fly on an all-new SpaceX capsule with a modified toilet system to fix the issue that caused the urine to leak.

The departure of Crew-2 astronauts on Monday leaves Russian Commander Anton Shkaplerov, Cosmonaut Pyotr Dubrovnik and NASA Astronaut Mark Vande Hei behind at the space station.

They will be joined by the next four Crew Dragon astronauts on Thursday, assuming the Crew-3 mission takes off as planned on Wednesday evening.

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Follow Stephen Clark on Twitter: @ StephenClark1.

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