Tomorrow (Saturday, 5 September), the first human in history to command as many as five long-duration missions to an Earth-circling space station will hand over the reins of the International Space Station (ISS) to the first American ever to helm the orbital outpost on two occasions. Russia’s Gennadi Padalka, who earlier this year surpassed fellow cosmonaut Sergei Krikalev as the world’s most seasoned spacefarer, with a cumulative 2.4 years of his life spent away from the Home Planet, has also already secured another record as the first person to command four discrete ISS expeditions. Shaking his hand in what is bound to be an emotional change-of-command ceremony will be the incoming Expedition 45 Commander, U.S. astronaut Scott Kelly. According to NASA, the ceremony is due to be broadcast on NASA TV at 2:40 p.m. EDT Saturday. In so doing, Kelly—who, together with Russian cosmonaut Mikhail Kornienko, is currently 160 days into a projected 340-day stay aboard the ISS—will command the station through the next two increments, with Expedition 45 due to transition into Expedition 46 in mid-December. In the meantime, three new crew members were due to arrive at the ISS today (Friday, 4 September), two of whom will fly through next weekend, before returning to Earth with Padalka early on 12 September, whilst the other joins Kornienko and Kelly for the remainder of their long voyage, which is due to end in March 2016.
Since the permanent habitation of the ISS got underway with the arrival of the Expedition 1 crew—NASA astronaut Bill Shepherd and Russian cosmonauts Yuri Gidzenko and Sergei Krikalev—way back in November 2000, numerous Americans have commanded the multi-national outpost. With Padalka’s Expedition 44 in its final hours, the tally now stands as Russians having commanded 22 expeditions, with the United States in second place on 19 expeditions and the International Partners (IPs) of the European Space Agency (ESA), the Canadian Space Agency (CSA), and the Japan Aerospace Exploration Agency (JAXA) boasting one command apiece. “There is an expectation that the International Partners, other than the U.S. or Russia, will have its crewmembers have future commands,” NASA’s Rob Navias told AmericaSpace, “but those decisions have not yet been finalized, nor exactly when or who would be involved. It is based on the balance of contributions made by the other IPs to the ISS Program through the partnership’s bylaws.”
Of the Russians, Padalka has flown a record-breaking four long-duration ISS expeditions in April-October 2004, March-October 2009, May-September 2012, and his present mission, launched last 26/27 March. This came after a successful six-month stint in command of Mir in August 1998-February 1999. In second place is veteran cosmonaut Fyodor Yurchikhin, who commanded three ISS expeditions between April 2007 and November 2013, with fellow Russians Pavel Vinogradov and Oleg Kotov having commanded two missions apiece. Having said this, America boasts the first ISS Commander, Bill Shepherd, the first female ISS Commander, Peggy Whitson, and U.S. astronaut Mike Lopez-Alegria also led the longest single mission to the station to date.
With a substantially larger corps, balanced against significant Astronaut Office attrition following the end of the Space Shuttle Program, five NASA astronauts—Peggy Whitson, Mike Fincke, Jeff Williams, Don Pettit, and Suni Williams—have flown two long-duration expeditions, although none have commanded on both occasions. In so doing, Kelly becomes the first American to lead a second ISS expedition, with Jeff Williams expected to do likewise when he commands Expedition 48 through the summer of next year.
“The decision as to who commands the station is made by the Multilateral Crew Operations Panel (MCOP) of the International Partner representatives,” explained Mr. Navias. “More often than not, the command is rotated from an American commander to a Russian commander, and vice-versa, but it is not a set rule. Scott Kelly will be Commander for Expeditions 45-46 and, every so often, by agreement, either the U.S. or Russia will have consecutive commands.” By the time the station begins its 50th expedition in November 2016—led by NASA astronaut Shane Kimbrough—this pendulum is expected to shift, with 24 U.S. commands against 23 Russian commands.
Tomorrow’s changeover of command between Padalka and Kelly will be done with no fewer than nine humans together in space—the greatest number of people to be in residence aboard the ISS since November 2013. Under normal circumstances, six-person ISS expeditions follow an “indirect” rotation protocol, whereby a given three-member subset departs, temporarily reducing the station’s population to three, after which a trio of new residents arrives to increase it back to six. However, with Padalka due to return to Earth in mid-September, at the end of his standard six-month mission, and the need for another cosmonaut to replace him for the second half of Kelly and Kornienko’s long voyage, the Soyuz TMA-18M visiting mission was utilized to deliver veteran spacefarer Sergei Volkov to the ISS. Launched from Site 1/5 at the Baikonur Cosmodrome in Kazakhstan at 10:38 a.m. local time (12:38 a.m. EDT) on Wednesday, 2 September, Volkov was joined by Denmark’s first man in space, Andreas Mogensen, and late addition Aidyn Aimbetov of Kazakhstan. Aimbetov was added to the Soyuz TMA-18M crew in June, following the withdrawal from training of Spaceflight Participant (SFP) Sarah Brightman. In flying this mission, Aimbetov becomes only the third ethnic Kazakh to journey into space, following in the footsteps of his countrymen Toktar Aubakirov and Talgat Musabayev.
Contrary to earlier plans, it was decided not to pursue the standard four-orbit “fast rendezvous” regime to enable Soyuz TMA-18M to reach the ISS in six hours. Last week, ESA announced that the mission would revert to a longer, two-day flight profile, “due to the space station’s higher than usual orbit,” which had been raised by the engines of Russia’s Progress M-28M cargo spacecraft through a Debris Avoidance Maneuver (DAM), in response to a possible Micrometeoroid Orbital Debris (MMOD) event. “Because of the station’s higher altitude, reaching the weightless research facility is now more difficult,” ESA noted, “and Roscosmos decided to allow the Soyuz TMA-18M more time to rendezvous and dock.” Since Mogensen—who has a full plate of research experiments, primarily to be executed in Europe’s Columbus laboratory, as part of his “iriss” mission—and Aimbetov are only expected to remain aboard the ISS for a week, this necessitated significant replanning of their respective tasks. “Some experiments will undoubtedly have to be left for other astronauts to complete at a later date,” ESA explained. “Mission Control will be working through the weekend to fit the pieces into the new scheduling puzzle.”
At the time of writing, Soyuz TMA-18M—with Volkov in the center commander’s seat, flanked by Mogensen to his left side as Flight Engineer-1 and Aimbetov to his right side as Flight Engineer-2—were expected to dock at the station’s space-facing (or “zenith”) Poisk module at 1:42 p.m. Baikonur time (3:42 a.m. EDT) on Friday, 4 September. After a series of pressure and leak checks, the hatches were to be opened about 90 minutes later, allowing Volkov, Mogensen, and Aimbetov to meet the six-man Expedition 44 crew of Padalka, Kornienko, Kelly, Russian cosmonaut Oleg Kononenko, U.S. astronaut Kjell Lindgren, and Japan’s Kimiya Yui in space for the first time.
Following Saturday’s change of command, Kelly will lead the multi-national outpost for a little under six months, until his own return to Earth with Volkov and Kornienko on 2 March 2016. Early on 12 September, Padalka, Mogensen, and Aimbetov will board the Soyuz TMA-16M spacecraft and undock from the aft port of the Zvezda service module, before touching down in central Kazakhstan, near the city of Jezkazgan, about three hours later. This will wrap up Padalka’s fifth mission, and establish a world record of 878 days in space across his career, which represents about 2.4 years of the cosmonaut’s 57 years of life. Mogensen and Aimbetov will each add about ten days to their respective tallies at the start of their spacefaring careers.
Looking ahead to the remainder of 2015, current plans foresee Kelly and Lindgren performing up to three EVAs in the October-December timeframe, the first of which will center upon the relocation of Pressurized Mating Adapter (PMA)-3 from its present perch on the Tranquility node to its eventual position on the space-facing (or “zenith”) interface of the Harmony node. PMA-3 and its twin, PMA-2, which is affixed to the forward port of Harmony, are expected to provide backup and prime docking interfaces for Boeing’s CST-100 and SpaceX’s Dragon V-2 Commercial Crew vehicles. However, a pair of International Docking Adapters (IDAs) must first be installed onto the PMAs to make them compatible with the new vehicles. IDA-1, destined for attachment to PMA-2, was lost in the explosion of SpaceX’s CRS-7 Dragon cargo flight on 28 June, placing all subsequent missions in jeopardy, including the planned CRS-9 flight to deliver IDA-2 to the station.
Despite initial hopes that SpaceX might be in a position to resume mission operations in September, it has been suggested by Novosti Kosmonavtiki that 16 November is the earliest possible date for the next Dragon (CRS-8) to launch. However, SpaceX told AmericaSpace that no provisional launch dates had been released yet and it remains to be seen if CRS-8 or another payload will fly the Return to Flight mission. Despite some speculation that IDA-2 might be “fast-tracked” onto an earlier mission, SpaceX told us that the CRS-8 primary payload remains the Bigelow Expandable Activity Module (BEAM), but stressed that “we’re still a ways from locking-in exact dates/manifest.” In addition to SpaceX’s upcoming return to flight, Orbital Sciences Corp.—whose ORB-3 Cygnus cargo ship vanished in a ball of fire, seconds after liftoff, last 28 October—is expected to launch its next mission no sooner than 4 December, atop a United Launch Alliance (ULA) Atlas V 401 booster.
A second direct rotation of crew members will occur on 15 December, with the launch of Soyuz TMA-19M and Russia’s Yuri Malenchenko, U.S. astronaut Tim Kopra, and Britain’s Tim Peake to briefly expand Expedition 45 up to nine members. Another direct rotation for 2015 was not originally timetabled, but has been added in order to maximize the time spent in orbit by the Soyuz TMA-17M crew of Kononenko, Lindgren, and Yui, the beginning of whose six-month flight was postponed from May to July, and which is being correspondingly extended from 5 November until 22 December. In anticipation of the Soyuz TMA-19M arrival, Kononenko, Lindgren, and Yui will relocate their Soyuz TMA-17M spacecraft to Zvezda-aft, opening up Rassvet for the new arrivals. Soyuz TMA-17M will then return to Earth, marking the dawn of Expedition 46—also under Kelly’s command—which will run through the end of the One-Year Mission in early March 2016. Interestingly, this will make Kononenko, Lindgren, and Yui the only long-duration crew of the ISS era in which none of its members rotated to command the next increment.
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