The Russian Soyuz TMA-22 spacecraft, known by its US designation of 28S, undocked from the International Space Station (ISS) and landed safely in Kazakhstan Friday morning after a five and a half month stay in space, carrying three crewmembers of the ISS crew back to Earth and beginning the Expedition 31 mission aboard the station.
Soyuz TMA-22 background:
The Soyuz TMA-22/28S spacecraft launched to the ISS on 14th November last year, with a docking to the ISS at the Mini Research Module-2 (MRM-2) Zenith port two days later on 16th November, delivering American astronaut Dan Burbank, and Russian cosmonauts Anton Shkaplerov and Anatoly Ivanishin to the ISS to serve on the Expedition 29 and 30 missions.
The launch – which was the first crewed launch since the retirement of the Space Shuttle last July and the first crewed launch since the failure of the Progress M-12M spacecraft last August – put an end to fears of a need to decrew the ISS in light of the grounding of the Soyuz booster after the August Progress failure.
The Soyuz TMA-22 spacecraft is also the last in the line of TMA (200 series) variant Soyuzes, as all Soyuzes hereafter will be of the newer TMA-M (700 series) variant, AKA “digital” Soyuzes. Thus, when Soyuz TMA-22 leaves space Friday morning, it will mark the last time that the venerable TMA variant of the Soyuz is in space.
Despite arriving at the ISS roughly one and a half months late due to delays associated with the August Progress M-12M failure, Soyuz TMA-22 will still be departing the ISS after the usual duration of five and a half months on-orbit, since the spacecraft’s stay on the ISS was extended by roughly one and a half months due to delays relating to the accidental overpressurisation of Soyuz TMA-22’s replacement vehicle – Soyuz TMA-04M/30S.
The Soyuz TMA-22 landing was scheduled for 30th April, but was moved forward three days to the 27th April due to upcoming Russian holidays.
Undocking and landing:
After saying goodbye to their crewmates remaining on the ISS, the three Soyuz TMA-22 crewmembers entered their spacecraft a few hours prior to undocking. Following which the removal of docking clamps holding the Soyuz onto the ISS, followed by hatch closure between the Soyuz and ISS, the depressurisation and subsequent leak checks of the vestibule between the two hatches was conducted.
The Soyuz TMA-22 crew – in their Sokol launch and entry suits – then strapped into the Descent Module for landing.
Handover of ISS attitude control to the Russian Segment (RS) of the ISS was conducted, maneuvering the ISS under Russian Service Module (SM) control to the undocking attitude (90 degrees pitch up from LVLH), along with the issuing of the ISS free drift command, allowing Soyuz TMA-22 to undock from the MRM-2 Zenith port at 8:15 AM GMT.
Soyuz TMA-22 – flown by Soyuz Commander Anton Shkaplerov and Soyuz Flight Engineers Anatoly Ivanishin and Dan Burbank – then conducted a 15 second separation burn to place the spacecraft on a trajectory away from the ISS.
Around two and a half hour later, during which time the ISS will maneuver back to its normal attitude, Soyuz TMA-22 conducted a roughly four and a half minute de-orbit burn at 10:49 AM GMT, placing the spacecraft on a sub-orbital trajectory with its perigee (lowest point) inside Earth’s atmosphere.
The next event came at 11:18 AM GMT, with tri-module separation of the Soyuz’s Orbital Module (BO), Descent Module (SA) and Instrumentation & Propulsion Module (PAO). Entry interface into Earth’s atmosphere will occurred three minutes later at 11:21 AM GMT, during which Soyuz TMA-22’s SA protected its precious cargo of humans and experiment downmass from the fiery heat of re-entry.
Following nine minutes of re-entry, parachute deployment occurred at 11:30 AM GMT, followed finally by landing 11:45 AM GMT near the town of Araklyk in Kazakhstan. The crew will then later be extracted from the Soyuz and flown by helicopter to a nearby airfield, with the Soyuz TMA-22 crew then parting ways after six months together, with Russians Anton Shkaplerov and Anatoly Ivanishin heading by aircraft to Moscow, and American Dan Burbank doing a “direct return” to Houston, Texas via a NASA aircraft.
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Hardware replacements and modifications:
In the past few days, a couple of hardware replacements and modifications have been made to the Soyuz TMA-22 spacecraft in order to get it ready to depart the ISS.
The first, performed on Tuesday, related to the KhSA Cooler/Dehumidifier Assembly fan box inside the Descent Module, which on 15th March had deactivated, thus requiring it to be Removed & Replaced (R&Rd) for undocking and landing. Steps included removal of the old fan box and installation of a new one in its place, hooking up cables to the new fan box, and telemetry checkouts.
The second modification, also performed on Tuesday in the Descent Module, related to the Anatoly Ivanishin’s personal seat liner for his Kazbek couch – specifically the headrest and lower section.
During a recent Kazbek couch fit check, a standard procedure conducted before all Soyuz landings, Ivanishin noted that he was having difficulty fitting into his customised seat liner, a problematic issue for landing since the seat liners help cushion crewmembers from the impact of touchdown.
As such, the crew were asked to reduce the thickness of the foam at the top of the head and around the hip area of the seat liner, using the “makita electric jig saw, a serrated knife, regular knife, hand hacksaw, cutter and lots of US grey tape”, in order to improve the fit.
On Wednesday, another fit check was performed to verify the issue is now resolved, this time using a ruler to measure clearances.
Expedition 31 begins:
As soon as Soyuz TMA-22 undocks from the ISS, Expedition 30 will end and Expedition 31 will begin, with Russian cosmonaut Oleg Kononenko as ISS Commander, having assumed command from Dan Burbank earlier this week, and American astronaut Don Pettit and European astronaut André Kuipers as Flight Engineers.
Despite being at three crew operations until the Soyuz TMA-04M/30S spacecraft arrives on 17th May with three additional Expedition 31 crewmembers – Russians Gennady Padalka and Sergei Revin, and American Joe Acaba – the three-person Expedition 30 crew will nevertheless be extremely busy over the next few weeks.
As currently scheduled – as much as the date remains only a No Earlier Than (NET) date – the SpaceX Dragon spacecraft is set to launch on its inaugural flight to the ISS on 7th May, for a capture and berthing to the ISS three days later on 10th May – to be performed by Don Pettit and André Kuipers. As such, both Pettit and Kuipers will be busy over the coming weeks brushing up on their “track and capture” skills using onboard robotics simulators.
While the current schedule calls for Dragon to launch and berth to the ISS prior to the Soyuz TMA-04M launch, if SpaceX deicide they need more time to fully test Dragon’s complex software, NASA may decide to wait until after the Soyuz TMA-04M launch and docking to launch the Dragon – meaning Dragon would arrive at the ISS will a full crew of six aboard the station.
In addition to the first ever visit of a commercial spacecraft to the ISS, other tasks for Expedition 31 include the usual heavy schedule of scientific research activities aboard the station, along with standard systems maintenance and repairs. Expedition 31 will end with the undocking and landing of Soyuz TMA-03M/29S on 1st July.
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