Two weeks ahead of Christmas, and 11 days sooner than originally manifested, the Soyuz TMA-17M spacecraft and its crew of Russian cosmonaut Oleg Kononenko, U.S. astronaut Kjell Lindgren and Japan’s Kimiya Yui have returned safely to Earth, wrapping up an occupany of more than 4.5 months aboard the International Space Station (ISS). After bidding farewell to their incumbent Expedition 45 crewmates Scott Kelly, Mikhail Kornienko and Sergei Volkov, the hatches were closed between the station and the Soyuz at 1:32 a.m. EST Friday, ahead of a smooth undocking at 4:50 a.m. A little more than three hours later, at 8:12 a.m. EST (7:12 p.m. local time), the bell-shaped descent module was guided to a parachute- and rocket-assisted touchdown on the desolate steppe of central Kazakhstan, northeast of the industrial city of Jezkazgan. Closing out their first career missions, Lindgren and Yui have each accrued more than 141 days in orbit, whilst Kononenko—who has two previous ISS expeditions to his credit—is now the world’s 13th most seasoned spacefarer, with a cumulative 533 days, or 18 months, spent “off the planet”.
As described in yesterday’s review of Soyuz TMA-17M’s time on-orbit, the 22 July-launched increment spanned the final weeks of Expedition 44—commanded by the world’s most experienced spacefarer, Gennadi Padalka—and crossed over with the September “direct rotation” of crew members aboard Soyuz TMA-18M, which saw Denmark send its first man into orbit, and concluded with the curtain falling on Expedition 45, led by One-Year crewman Scott Kelly. Yui became only the second Japanese astronaut to oversee the capture and berthing of one of his country’s H-II Transfer Vehicle (HTV) cargo ships, whilst Lindgren performed a pair of EVAs with Kelly to tend to station external maintenance and an effort to restore the troubled cooling system on the P-6 truss to its original configuration. Lindgren’s final major act of the mission, just two days ago, on 9 December, involved the successful capture and berthing of Orbital ATK’s OA-4 Cygnus cargo ship at the Earth-facing (or “nadir”) port of the station’s Unity node. This marked the first-ever occasion that Unity nadir had been utilized for a Commercial Cargo visitor.
It was clearly a poignant time for Lindgren, in particular, and his regular Twitter updates have included several wistful views of the Home Planet, including a stunning perspective of California’s Central Valley, suitably “photobombed” by the aft segment of the Soyuz TMA-17M spacecraft, which he described as “our ride home”. As December dawned, the crew performed a leak check on their Russian-built Sokol (“Falcon”) launch and entry suits, which offered a few moments of fun as they presented themselves as See No Evil (Kononenko), Speak No Evil (Yui) and Hear No Evil (Lindgren). “The time has flown by,” Lindgren tweeted on 4 December. “Starting to prepare for our return. Spacesuits…check.” Clearly, the experience of becoming one of just a few hundred humans to have ventured beyond Earth’s “sensible” atmosphere and into space was not lost on Lindgren. “What an honor,” he mused on 5 December, “to have slipped the surly bonds of Earth.”
Earlier this week, Lindgren led the successful capture and berthing of Orbital ATK’s OA-4 Cygnus cargo ship at the station’s Earth-facing (or “nadir”) Unity node. After this event, he and his crewmates set about their final preparations for a return to Earth. “Next crew is @astro_tim @astro_timpeake & Yuri Malenchenko,” he tweeted yesterday to his 60,300 followers, referring to the upcoming Soyuz TMA-19M crew, which is due to launch on Tuesday, 15 December. “Enjoy this view guys. I know I have.” In response, Britain’s Tim Peake—who is presently in the midst of his final days on Earth, ahead of launch—tweeted: “Incredible view…thanks Kjell. Safe travels back to planet Earth today!”
In the small hours of Friday morning, Kononenko, Lindgren and Yui bade farewell to their Expedition 45 crewmates Scott Kelly of NASA and Russian cosmonauts Mikhail Kornienko and Sergei Volkov, all of whom are expected to remain aboard the station until March 2016. “All loaded up!” Lindgren tweeted, showing a photograph of himself and his crew buttoned up in the Soyuz TMA-17M descent module. “Farewell to our Exp 45 crewmates and the magnificent International @Space_Station! Hello Earth!!”
Hatches between the station’s nadir-facing Rassvet module and the Soyuz TMA-17M spacecraft were closed at 1:32 a.m. EST Friday and, following standard leak and pressure checks, the crew—with Kononenko occupying the center seat, commanding the return to Earth, flanked by Yui in the left-hand “Flight Engineer-1” position and Lindgren in the right-hand “Flight Engineer-2” position—ran through standard pre-undocking procedures. The command to open hooks and latches was issued shortly thereafter and physical separation of Soyuz TMA-17M from the ISS occurred at 4:50 a.m. EST. The spacecraft, which consisted of the bell-shaped descent module for the crew, together with a spherical orbital module and cylindrical instrument module, departed the vicinity of the space station at an initial rate of about 4.7 inches (12 cm) per second.
“Fair winds and following seas my friends!” tweeted Scott Kelly, who transitioned from Commander of Expedition 45 to Expedition 46 at the moment of undocking. “Safe landing @astro_kjell, @Astro_Kimiya & Oleg!” Added Italy’s first woman in space, Samantha Cristoforetti—who returned from the station aboard Soyuz TMA-15M in June—“Now the parking spot is free. Can’t wait to see my fellow @ESA astronaut @astro_timpeake on ISS!” When Soyuz TMA-17M reached a distance of 50-65 feet (15-20 meters), Kononenko oversaw a short, eight-second “burn” to increase the distance between the two vehicles.
A little more than two hours later, at 7:20 a.m. EST, the “deorbit burn” was performed to slow Soyuz TMA-17M by about 420 feet per second (128 meters per second) and commit it to a fiery descent back through Earth’s “sensible” atmosphere. The burn lasted for four minutes and 41 seconds, by which time the spacecraft occupied an orbit of 257.7 miles (414.8 km). At 7:46 a.m. EST, some 27 minutes after the conclusion of the deorbit burn—and almost three hours since undocking from the ISS—the orbital and instrument modules were jettisoned, leaving the descent module alone to endure the furnace of re-entry. By this stage of the flight, Kononenko, Lindgren and Yui were at an altitude of 458,989 feet, which equates to about 86.9 miles (139.9 km).
“Entry Interface”, the point at which the spacecraft is subjected to rapid heating of its surfaces, due to friction with steadily thickening atmospheric gases, was reached at 7:50 a.m. EST, at an altitude of 329,068 feet, or 62.3 miles (100.3 km). By this time, Kononenko, Lindgren and Yui were flying high above strife-torn northern Iraq and Syria, according to a ground track tweeted by Capcom Doug “Wheels” Wheelock. Streaking back to Earth, Soyuz TMA-17M appear meteor-like to observers on the ground. Passing through the worst of re-entry heating, the command to open the parachutes was issued at about 7:58 a.m. EST, whilst at an altitude of 6.6 miles (10.7 km), and involved the release of two “pilot” chutes, followed by the 258-square-foot (24-square-meter) drogue and finally the 10,764-square-foot (1,000-square-meter) main canopy. These progressively slowed the descent module, firstly to 180 mph (290 km/h), and finally to 16.4 mph (26.4 km/h). The latter was still too fast for a safe landing and, moments before ground impact, six solid-fueled rockets in Soyuz TMA-17M’s base ignited to slow the spacecraft to 5 feet (1.5 meters) per second cushion the touchdown.
“They’ve landed!” came the call from Russian recovery forces and touchdown occurred in blizzard conditions at 8:12 a.m. EST (7:12 p.m. local Kazakh time), about 103 minutes after local sunset, marking the sixth nocturnal Soyuz landing of the ISS era. That said, several pre-ISS night landings were accomplished, notably the unintentional splashdown of Soyuz 23 in the icy waters of Lake Tengiz, in north-central Kazakhstan, in October 1976.
Since their launch from Baikonur, last 22 July, the crew had spent a total of 141 days, 16 hours and nine minutes and circled the Home Planet more than 2,200 times. Concluding his third space mission—after the six-month Expedition 17 in April-October 2008 and the six-month Expedition 30/31 in December 2011-July 2012—Kononenko has now accrued a career total of 533 days, making him the world’s 13th most seasoned spacefarer. As for Lindgren and Yui, they have now secured more than 4.5 months of space-time under their belts. Perhaps the greatest honor and recognition, though, came from their final skipper, Scott Kelly, who tweeted earlier today: “They arrived in space like baby birds barely able to fly & now they soar home as eagles.”