‘What an Honor’: Space Station Crew Prepares for Friday Return to Earth

Eleven days sooner than originally planned, the Soyuz TMA-17M crew of Russian cosmonaut Oleg Kononenko, U.S. astronaut Kjell Lindgren and Japan’s Kimiya Yui are set to return to Earth tomorrow (Friday, 11 December), wrapping up a 4.5-month increment aboard the International Space Station (ISS) as part of Expeditions 44 and 45. Having flown under the respective commands of the world’s most experienced spacefarer, Gennadi Padalka, and most recently One-Year crewman Scott Kelly, the trio are due to undock from the Earth-facing (or “nadir”) Rassvet module of the station at 4:49 a.m. EST and their spacecraft’s bell-shaped descent module is expected to reach terra firma on the desolate steppe of Central Kazakhstan at 8:12 a.m. EST (7:12 p.m. local time). Closing out their first career missions, Lindgren and Yui will each accrue more than 141 days in orbit, whilst Kononenko—who has two previous ISS expeditions to his credit—will establish himself in 13th place on the list of the world’s most seasoned spacefarers, totaling in excess of 533 days.

As outlined in a previous AmericaSpace article, the launch of Soyuz TMA-17M was planned for 26/27 May, but was postponed by almost two months, primarily due to the April failure of Russia’s Progress M-27M cargo ship and subsequent booster inspections. In response to this incident—and in order to maximize their time on-orbit—their scheduled return to Earth was correspondingly moved back from 5 November to 22 December. Following a smooth launch, the crew docked smoothly at the Rassvet module about six hours later, forming the second half of Expedition 44, which then consisted of One-Year crew members Kelly and Russian cosmonaut Mikhail Kornienko, commanded by Padalka. This crew had been launched aboard Soyuz TMA-16M in March.

During the course of their stay, the new crew welcomed the Japan Aerospace Exploration Agency’s (JAXA) fifth H-II Transfer Vehicle (HTV-5), laden with supplies, and Yui became only the second of his countrymen to oversee its rendezvous and Canadarm2-assisted berthing at the nadir port of the Harmony node on 24 August. Soyuz TMA-18M arrived in early September, carrying Russia’s Sergei Volkov, Kazakhstan’s Aidyn Aimbetov and the first Danish astronaut, Andreas Mogensen. This “direct handover” of crews temporarily boosted Expedition 44 to nine members for the first time in almost two years. On 11/12 September, Padalka, Aimbetov and Mogensen returned to Earth aboard Soyuz TMA-16M, leaving Volkov to join Kelly and Kornienko for the second half of their long mission.

In the meantime, Kononenko, Lindgren and Yui pressed on with their own increment. In late October, they celebrated their 100th day in space—an event which they tweeted excitedly to their Earth-bound audience—and on 2 November the Expedition 45 crew observed 15 years of continuous occupation of the ISS. They offered eerie Halloween greetings to their Earthly audience and Lindgren honored the passing of Wyle Labs research scientist and astronaut instructor Victor Hurst IV with a poignant bagpipes performance of “Amazing Grace”. Together with Kelly, Lindgren also participated in two spacewalks, totaling just over 15 hours, to perform ISS upgrades and restore the P-6 Integrated Truss Structure (ITS) cooling system back to its original configuration, after several years of ammonia leaks and other problems.

Initial planning called for a second direct handover of crews in December, with Soyuz TMA-19M expected to launch from Baikonur on 15 December, carrying Russian cosmonaut Yuri Malenchenko, U.S. astronaut Tim Kopra and Britain’s Tim Peake. A week later, Kononenko, Lindgren and Yui would board Soyuz TMA-17M and return to Earth, after 153 days in space. However, as detailed in a recent AmericaSpace article, their return date was brought forward by 11 days, in response to an anticipated intensity of Visiting Vehicle (VV) traffic in the December-January timeframe, in particular the maiden launch of Russia’s new Progress-MS spacecraft.

As December dawned, the Soyuz TMA-17M crew performed a leak check on their Russian-built Sokol (“Falcon”) launch and entry suits in the station’s Destiny laboratory, 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.” He later shared an impressive vista of California’s Central Valley, “with our ride home in the foreground”, the base of the highly reliable Soyuz spacecraft, which has staged more than 125 piloted voyages into orbit since April 1967. 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.”

Under the current plan, the outgoing crew will bid Kelly, Kornienko and Volkov—who will now rotate into the “core” of Expedition 46 through March 2016—farewell and hatches between the Rassvet module and spacecraft to be closed at about 1:25 a.m. EST tomorrow (Friday). After standard leak and pressure checks of the spacecraft and their Sokol suits, 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—will run through their standard pre-undocking procedures. The command to open hooks and latches will be issued and physical separation of the spacecraft from the ISS expected to occur about 90 seconds later at 4:49 a.m. The spacecraft, which consists of the bell-shaped descent module for the crew, together with a spherical orbital module and cylindrical instrument module, will depart the vicinity of the space station at a initial rate of about 4.7 inches (12 cm) per second.

When Soyuz TMA-17M reaches a distance of about 50-65 feet (15-20 meters), Kononenko will oversee a short, eight-second “burn” of the spacecraft’s engines to increase the distance between the two vehicles. A little more than two hours later, at 7:19 a.m. EST, and having by now reached a distance of about 7.5 miles (12 km) from the ISS, the “deorbit burn” will be conducted 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 will last for four minutes and 41 seconds, by which time the spacecraft will inhabit an orbit of about 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 will be jettisoned, leaving the descent module alone to endure the furnace of re-entry. By this stage of the flight, Kononenko, Lindgren and Yui will be 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, will be reached at 7:49 a.m. EST, at an altitude of 329,068 feet, or 62.3 miles (100.3 km). Streaking back to Earth, and with the crew expected to endure peak loads of 4-5 Gs, Soyuz TMA-17M will appear meteor-like to observers on the ground.

Passing through the worst of re-entry heating, the command to open the parachutes will be issued at 7:58 a.m. EST, whilst at an altitude of 6.6 miles (10.7 km), and will involve 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 will progressively slow the descent module, firstly to 180 mph (290 km/h), and finally to 16.4 mph (26.4 km/h). The latter is still too fast for a safe landing and, moments before ground impact, six solid-fueled rockets in Soyuz TMA-17M’s base will ignite. These will slow the spacecraft to 5 feet (1.5 meters) per second and serve to cushion the touchdown.

According to NASA, Kononenko, Lindgren and Yui will reach terra firma at 8:12 a.m. EST (7:12 p.m. local Kazakh time) on 11 December, about 103 minutes after local sunset. Assuming this landing schedule holds, it will leave Kononenko with a cumulative total across his three long-duration ISS expeditions of more than 533 days, placing him in 13th place on the list of the world’s most seasoned spacefarers. Lindgren and Yui will both wrap up their first career missions, with a total of slightly more than 141 days.

 

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