Scott Kelly has certainly been waxing lyrical recently, as he wraps up the last couple of percent of his (almost) year-long increment aboard the International Space Station (ISS). Last week, as he passed Day 330, he stopped counting “up” and began counting “down”, as he entered the final ten days of his historic mission. This is due to conclude late Tuesday/early Wednesday, when he and Russian cosmonauts Mikhail Kornienko and Sergei Volkov alight on the desolate steppe of north-central Kazakhstan.
Over the last few days, Kelly has tweeted “throwback” images of his last hours on Earth, back in March 2015, juxtaposed with wistful “EarthArt” images of the views he will miss. These include the striking colors of Africa, the mesmerizing patterns of sand-dunes, his final orbital sunrises and sunsets and a “Top of the World” perspective of the glorious Himalaya. When the crew lands aboard the Soyuz TMA-18M spacecraft, Kelly and Kornienko will finish the fourth-longest single space mission in human history—at more than 340 days—whilst Volkov closes out a shorter, six-month expedition.
Earlier this week, Kelly shared an image of himself and his two crewmates performing a “fit-check” of their Russian-built Sokol (“Falcon”) launch and entry suits, within the cramped confines of Soyuz TMA-18M. “Seems like a year ago”, Kelly quipped, as he continued a day-by-day countdown to his return to Earth, which finally reached single figures on Sunday, 21 February. It has been a long mission, and one which has brought Kelly and his multitude of crewmates many changing fortunes, but one which will undoubtedly offer significant benefits as NASA seeks to deliver humans beyond low-Earth orbit early in the next decade. As described in a previous AmericaSpace article by Emily Carney, Kelly’s research has included medical and biological experiments and has involved parallel testing on his identical twin brother, Mark, who is also a veteran astronaut.
Launched aboard Soyuz TMA-16M from the Baikonur Cosmodrome in Kazakhstan, last 26/27 March, Kelly and Kornienko were joined for their first six months by Russian cosmonaut Gennadi Padalka and have since seen the arrival and departure of no fewer than nine spacefarers, including representatives of Italy, Japan, Denmark, Kazakhstan and, most recently, the United Kingdom.
With the return of Padalka to Earth in September, Kelly became the first American to command as many as two discrete ISS increments—having previously led Expedition 26 from November 2010 into March 2011—and his long mission positioned him to secure a raft of personal and national records in the final half of his flight. In mid-October, he surpassed fellow astronaut Mike Fincke’s 381-day cumulative achievement for the greatest amount of time spent in space by a U.S. citizen, whilst at the end of that same month he passed Mike Lopez-Alegria’s 215-day achievement for the longest single mission in U.S. spaceflight history. He also secured the additional record of becoming the first American to perform an EVA so deep (215 days) into a space mission, when he performed a spacewalk with Kjell Lindgren last 28 October. This knocked the previous record-holder, Rick Mastracchio, who made an EVA in April 2014, 167 days into his Expedition 38/39 mission, off the top spot. Kelly went on to twice eclipse his own record, performing two more EVAs on 6 November and 21 December, the latter of which came 268 days into his long mission. More recently, on 21 January, he became the first American to pass 300 days in space on a single mission, before hitting a cumulative 500 days across the span of his four-flight astronaut career on 10 February.
In fact, only six other humans—Soviet and Russian cosmonauts Yuri Romanenko, Vladimir Titov, Musa Manarov, Sergei Krikalev, Sergei Avdeyev and the current record-holder for the longest-ever space mission in human history, Valeri Polyakov—have surpassed 300 days on a single flight. At this precise moment, Kelly and Kornienko are flying the fourth-longest single space mission; as of today (Friday, 26 February), they have accrued more than 335 days in orbit. This puts them well ahead of Romanenko’s 326-day achievement, which was set aboard the Mir space station in December 1987, yet falls just a few weeks shy of the 366-day accomplishment of Titov and Manarov, established way back in December 1988.
Prior to his departure, Kelly will transfer command of the ISS to U.S. astronaut Tim Kopra, who arrived in mid-December aboard Soyuz TMA-19M. Kopra will lead Expedition 47 through early June, initially at a three-man capability, alongside Russian cosmonaut Yuri Malenchenko and Britain’s Tim Peake. However, on 19 March, Soyuz TMA-20M will bring a new crew of Russian cosmonauts Alexei Ovchinin and Oleg Skripochka and NASA’s Jeff Williams, restoring the space station to a nominal, six-man strength. In doing so, Kopra will continue what is expected to be a full year of U.S. commands of the multi-national orbiting outpost. Kelly has commanded the ISS since September 2015 and following the scheduled return of Kopra’s crew in early June, Williams will take the helm and lead Expedition 48 through his own departure in September 2016. This will mark the longest continuous period that the station has been under U.S. command.
On Tuesday, 1 March, Kelly, Kornienko and Volkov will bid farewell to Kopra, Malenchenko and Peake and don their Sokol suits, before boarding the bell-shaped descent module of Soyuz TMA-18M. Hatch closure is scheduled for 4:40 p.m. EST. The spacecraft is presently docked at the station’s space-facing (or “zenith”) Poisk module, which projects radially from the multiple docking adapter of the Zarya module. After standard pressure and leak checks of the spacecraft and their suits, the crew—with Volkov in the center seat, commanding the return to Earth, flanked by Kornienko in the left-side “Flight Engineer-1” position and Kelly in the right-side “Flight Engineer-2” position—will run through standard pre-undocking procedures.
The command to open hooks and latches will be issued at 8:03:30 p.m. EST and physical separation of Soyuz TMA-18M from Poisk will come about 90 seconds later, at 8:05 p.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 ISS at an initial rate of about 4.7 inches (12 cm) per second.
At 8:08 p.m., having by now reached a distance of 50-65 feet (15-20 meters), Volkov will oversee a short, eight-second “burn” of the spacecraft’s engines to increase the distance between themselves and the station. Eighty seconds later, a second burn of 30 seconds’ duration will further increase the separation gap. This will create the proper conditions for Soyuz TMA-18M to execute a 280-second “deorbit burn” at 10:34:13 p.m. EST. By this stage, Volkov, Kornienko and Kelly will have reached a distance of about 7.5 miles (12 km) from the ISS and the deorbit burn will serve to slow the spacecraft by about 420 feet per second (128 meters per second) and commit the three spacefarers to a fiery descent back through the “sensible” atmosphere. By this stage, Soyuz TMA-18M will inhabit an orbit of about 257.7 miles (414.8 km).
Meanwhile, at the landing site in north-central Kazakhstan, dawn will by now have broken on the morning of Wednesday, 2 March. Sunrise will occur at 7:57 a.m. local time on 2 March (8:57 p.m. EST on 1 March) and recovery forces will begin the process of converging on the prime recovery zone.
Twenty-three minutes after the completion of the deorbit burn, and almost three hours since departing the ISS, the orbital and instrument modules of Soyuz TMA-18M will be jettisoned, leaving the descent module alone to endure the furnace of re-entry. By this stage, Volkov, Kornienko and Kelly will be at an altitude of 458,661 feet, which equates to about 86.86 miles (139.8 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 11:04:18 p.m. EST, at an altitude of 328,412 feet, or 62.2 miles (100.1 km). Streaking back to Earth, and with the crew expected to endure peak loads of 4-5 G, Soyuz TMA-18M 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 initiated at 11:12:24 p.m. EST, whilst at an altitude of 6.6 miles (10.7 km), and will involve the release of a pair of “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 km (26.4 km/h). As well as reducing the descent rate, the main canopy also allows the Soyuz to descend at a 30-degree angle to expel heat, before shifting the spacecraft to a straight-vertical descent. However, the latter is still too fast for a safe landing and, moments before impact, at an altitude of 2.6 feet (0.8 meters) above the ground, six solid-fueled rockets in Soyuz TMA-18M’s base will ignite. These will slow the spacecraft to five feet (1.5 meters) per second and cushion the touchdown.
And that touchdown will be an historic one to behold. Scheduled to occur at 11:27:24 p.m. EST on Tuesday, 1 March (10:27:24 a.m. local time on Tuesday, 2 March), it is expected to occur about 92 miles (148 km) south-east of the Kazakh industrial city of Dzhezkazgan, about 2.5 hours after local sunrise. Predicted landing co-ordinates for Soyuz TMA-18M are 47.21 degrees North latitude and 69.35 degrees East longitude. The crew will be extracted from the descent module and are expected, weather-permitting, to undergo medical tests at the landing site. On hand at the landing site to greet the crew will be NASA’s chief astronaut, Chris Cassidy. Volkov and Kornienko will fly back to the Star City cosmonauts’ training center, on the forested outskirts of Moscow, whilst Kelly is expected to return to Ellington Field, near the Johnson Space Center (JSC) in Houston, Texas, about 24 hours after landing.
An on-time touchdown will produce a total elapsed time for the first (almost) year-long mission of the 21st century of 340 days, 8 hours and 45 minutes for Kelly and Kornienko, together with around 5,400 orbits of Earth. When added to their previous spaceflight experience—180 days for Kelly, spread across two shuttle missions and the Expedition 25/26 increment, and 176 days for Kornienko, counting his previous stint on Expedition 23/24—this will position the two men in 17th and 18th places on the list of the world’s most seasoned space travelers. As for Volkov, who will wrap up almost 182 days aloft, the irony is that he will surpass both Kelly and Kornienko in terms of cumulative time in space. Volkov already has two prior long-duration missions under his belt and at the instant of Soyuz TMA-18M’s touchdown he will have totaled almost 548 days across his three flights, which sets him in tenth place on the list of most experienced spacefarers.
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