The incumbent Expedition 47 core crew of the International Space Station (ISS)—Commander Tim Kopra of NASA, Russian cosmonaut Yuri Malenchenko, and Britain’s first “official” astronaut, Tim Peake—will remain aboard the orbiting laboratory for longer than planned. On Friday, 29 April, the European Space Agency (ESA) announced that the trio will return to Earth aboard their Soyuz TMA-19M spacecraft on 18 June, almost two weeks later than the original 5 June target. It was noted by ESA that the extension will help to “keep the space station operating at full capacity with six astronauts,” whilst NASA’s Rob Navias added that it allows the International Partners (IPs) to “create efficiencies during a period of heavy scientific research work.” The launch of the next crew, aboard the maiden Soyuz-MS spacecraft, has correspondingly moved from 21 to 24 June.
The increment of Kopra, Malenchenko, and Peake has been longer than most. At the time of their launch from Baikonur Cosmodrome in Kazakhstan, last 15/16 December, they were targeted to spend close to six months in space. The inaugural mission of Russia’s fourth-generation Soyuz-MS spacecraft should have flown in March, carrying the second half of the Expedition 47 crew—NASA astronaut Jeff Williams and Russian cosmonauts Alexei Ovchinin and Oleg Skripochka—but due to technical issues with the new vehicle it was switched with the last mission of the older-specification Soyuz TMA-M. The first outing of Soyuz-MS, now carrying Russian cosmonaut Anatoli Ivanishin, NASA astronaut Kate Rubins, and Japan’s Takuya Onishi into orbit, was moved from 21 May to 21 June. In order to minimize the amount of time that the ISS would be at a reduced crew of three, the IPs agreed to extend Kopra, Malenchenko, and Peake’s landing date from 5 May to 5 June.
Following their arrival aboard the sprawling multi-national outpost, Kopra, Malenchenko, and Peake initially formed the second half of Expedition 46, commanded by Scott Kelly. Within days, Kelly and Kopra were called upon to perform an unplanned EVA to move and latch the station’s Mobile Transporter (MT), ahead of the arrival of Russia’s Progress-MS cargo ship. Less than a month into their stay, Kopra and Peake—with the latter becoming Britain’s first “official” spacewalker, wearing the Union Jack on the sleeve of his Extravehicular Mobility Unit (EMU) space suit—embarked on an EVA to replace a failed Sequential Shunt Unit (SSU) on one of the station’s eight power channels. In late February, just before the return to Earth of Kelly and his crew of Russian cosmonauts Mikhail Kornienko and Sergei Volkov, Tim Kopra assumed command of the ISS, kicking off Expedition 47. Two weeks later, the second half of his crew arrived in the form of Williams, Ovchinin, and Skripochka, restoring the station to full, six-person strength through the midsummer months.
Under Kopra’s command, the ISS has seen one of its busiest periods in terms of Visiting Vehicle (VV) traffic. Orbital ATK’s OA-6 Cygnus cargo ship—lofted atop a United Launch Alliance (ULA) Atlas V booster—arrived in late March, whilst SpaceX’s CRS-8 Dragon followed suit in the second week of April. Both spacecraft are currently berthed, respectively, at the Earth-facing (or “nadir”) interfaces of the Unity and Harmony nodes, marking the first occasion that the station has simultaneously hosted both of NASA’s Commercial Resupply Services providers. In the days after Dragon’s arrival, the Bigelow Expandable Activity Module (BEAM) was robotically transferred to the aft port of the Tranquility node, where it will be expanded on 27 May.
Current plans call for Dragon to be detached from the Harmony node on 11 May for its return to Earth, whilst Cygnus will now depart from the Unity node on 14 June. This is about three weeks later than originally planned and, if it occurs on time, will leave OA-6 as the longest single VV ever flown to the U.S. Orbital Segment (USOS). Counting from its arrival on 26 March, OA-6 will have been physically connected to the station for 80 days, pipping the previous record set by OA-4, which returned to Earth in February after almost 72 days of berthed operations.
According to NASA, Cygnus’ prolonged stay at the ISS allows for more time to pack unwanted items aboard the cargo ship for disposal in Earth’s upper atmosphere. In addition to the VV traffic, Kopra and his Expedition 47 crewmates have supported a wide range of research experiments and this is one of the reasons for the 13-day extension to their increment. “NASA and Roscosmos negotiated a reduction in the indirect handover period,” Mr. Navias told AmericaSpace on Friday, “so we could maintain a six-man crew on board for a slightly longer period of time and create efficiencies during a period of heavy scientific research work.”
Specifically, this includes ongoing rodent research, which has been ongoing through the recent One-Year mission and will continue through Expeditions 47 and 48. The Rodent Research-3-Eli Lilly payload—a U.S. National Laboratory investigation, sponsored by the Indianapolis, Ind.-based Eli Lilly and Co. pharmaceutical company and by the Center for the Advancement of Science in Space (CASIS)—was delivered to the ISS last month aboard the CRS-8 Dragon. It promotes ongoing efforts to explore bone and muscle-mass loss in the legs and spine during prolonged spaceflights. It has long been known that humans experience significant changes in bone density and muscle mass, within days of entering orbit, specifically in body parts which, on Earth, bear weight on the ground, including the legs, hips, and spine. Exercise has proven a useful mitigating tool, but remains insufficient as an effective countermeasure.
In time, these effects are known to create symptoms similar to those experienced by people with muscle-wasting diseases or limited mobility on Earth, such as muscular dystrophy, severe osteoporosis, cancer, spinal-cord injuries, and musculoskeletal fragility associated with the aging process. Mice are known to also undergo rapid bone and muscle-mass loss—sometimes in as little as 12 days of spaceflight exposure—and, similar to us, the effects are manifested in their hind limbs and spines. This has made them a valuable model for spaceflight-induced musculoskeletal disuse. Twenty mice were transported to space aboard the CRS-8 Dragon on 8 April and, upon arrival at the ISS, their habitats were installed in an EXPRESS rack. “At specified times the animals are transferred from habitat to the Microgravity Science Glovebox (MSG) to perform experimental procedures, such as injections or dissections,” NASA has noted. “At the end of the experiment, animals are euthanized and dissected.” Frozen tissues are stored in the space station’s Minus-Eighty-Degress Laboratory-Freezer to ISS (MELFI) and fixed tissue samples stored in ambient stowage, ahead of bagging and return to Earth.
For Tim Peake, who became Britain’s first “official” astronaut, sponsored by the UK Government—and the second British national to have journeyed into space, following the May 1991 commercial flight of Helen Sharman—it offers him some additional time remain aboard the orbital outpost. “Although I am looking forward to being back on Earth and seeing friends and family again, each day spent living in space is a huge privilege and there is much work to do on the station,” he explained. “The extension will keep the station at a full crew of six for several days longer, enabling us to accomplish more scientific research. And, of course, I get to enjoy the beautiful view of Planet Earth for a little while longer.” Peake also tweeted his 565,000 followers: “I get to stay an extra few days in space. Looking forward to being back, but loving it here and a lot more to do!”
With Kopra, Malenchenko, and Peake now targeted to undock from the station at about 5:47 a.m. EDT on 18 June and land in their Soyuz TMA-19M descent module, about three hours later, on the desolate steppe of Kazakhstan on 18 June, they will wrap up a voyage of slightly over 186 days in space. This will rank theirs within the Top 20 longest increments ever undertaken aboard the ISS during its 47-expedition history. It will also move Malenchenko—who is only the second Russian to chalk up a sixth space mission—into second place, behind Gennadi Padalka, on the list of most flight-seasoned space veterans of all time. When Soyuz TMA-19M reaches the ground, seven weeks hence, he will have accrued 827 days across his career, pipping current second-placeholder Sergei Krikalev and falling just a few weeks shy of Padalka’s 878-day empirical record.
Linked to the moved landing date, the launch of the maiden Soyuz-MS, with its crew of Ivanishin, Rubins, and Onishi, has moved from 21 to 24 June. “The three-day shift in the launch date was a companion to the shift in the landing date,” Mr. Navias told AmericaSpace, “to enable the Russian Search and Recovery Forces to redeploy from landing operations to launch operations downrange from Baikonur.” With the departure of Kopra, Malenchenko, and Peake, NASA’s Jeff Williams will assume command of Expedition 48, through his own crew’s return to Earth in early September.
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