Three new crew members, boasting a combined total of seven months of spaceflight experience and nearly three full days of spacewalking time between them, have begun a half-year voyage to the International Space Station (ISS). Veteran Russian cosmonaut Oleg Artemyev, joined by educator astronaut Ricky Arnold and seasoned Hubble Space Telescope (HST) repairman Drew Feustel rocketed away from Site 1/5 at the Baikonur Cosmodrome at 10:44:25 p.m. local time (12:44:25 p.m. EDT) Wednesday, 21 March. Aboard their Soyuz MS-08 spacecraft, the three men will spend two days in transit, before docking at the station’s space-facing (or “zenith”) Poisk module at 2:41 p.m. EDT Friday, 23 March.
At the beginning of 2018, there existed much speculation that Soyuz MS-08 would fly as soon as 15 March, possibly even testing a new “ultra-short” rendezvous regime, lasting just three hours and two orbits of Earth. However, it was later clarified by Roscosmos that the 15 March target was always “provisional” and that the 21st was eventually confirmed. Since March 2013, most Soyuz crews have followed a six-hour and four-orbit “fast rendezvous” to reach the station in a shorter period of time. However, three consecutive missions—last December’s Soyuz MS-07, today’s flight and the scheduled June voyage of Soyuz MS-09—have all reverted to the “standard” two-day and 34-orbit rendezvous profile, due to orbit-phasing constraints. “08 and 09 coming up happen to be scheduled on dates that do not allow phasing for the four-orbit rendezvous,” NASA’s Rob Navias told AmericaSpace. “Four-orbit rendezvous are desirable, but by no means mandatory. The Sept. launch [of Soyuz MS-10] will be a four-orbit rendezvous. Just depends on the launch date.”
Today’s crew brings a significant level of experience to the table for a complex increment, which is expected to last until late August. Artemyev, who commands Soyuz MS-08, previously logged over 169 days in orbit as a flight engineer on Expedition 39/40 in March-September 2014, during which he also completed two sessions of Extravehicular Activity (EVA), lasting 12.5 hours. Seated to his left side, in the Flight Engineer-1 position aboard the Soyuz, is Feustel, who previously served aboard STS-125 in May 2009 and STS-134 in May 2011, respectively the final servicing call to Hubble and the last voyage of shuttle Endeavour. In his two missions, Feustel spent 28.5 days in orbit and recorded more than 42 hours of EVA time in six spacewalks. Finally, in the right-hand Flight Engineer-2 seat is Arnold, who spent almost 13 days aloft during shuttle Discovery’s STS-119 mission in March 2009, logging 12.5 hours of spacewalking experience in two career EVAs.
That expertise will prove invaluable in a few days’ time, with Feustel (EV1) and Arnold (EV2) slated to venture outside the station on 29 March for 6.5 hours. Their primary task, according to NASA’s Rob Navias, is to install additional wireless communications hardware on the exterior of the Tranquility node, ahead of the arrival of the ECOSTRESS experiment aboard SpaceX’s CRS-15 Dragon in mid-June. The ECOSTRESS payload will be robotically installed onto the Exposed Facility of Japan’s Kibo lab. Feustel and Arnold’s work will help to assist with ECOSTRESS data collection, as well as enhancing the communications envelope for upcoming Commercial Crew vehicles, via the Common Communications for Visiting Vehicles (C2V2) architecture.
Additionally, the spacewalkers will remove a pair of flex-hoses from one of the station’s port-side radiator beam valve modules and swap-out cameras on the Camera Port-8 (CP-8) assembly on the P-1 truss element. In the event that Feustel and Arnold complete their tasks ahead of the timeline, a number of “get-aheads” may also be assigned to them. Specifically, they may be asked to install handle bars on the port-side and starboard-side Radiator Grapple Bars (RGBs) and break torque on bolts on a spare pump module on External Stowage Platform (ESP)-2 and a flex-hose rotary coupler on the S-1 truss. “This would economize time for these tasks,” Mr. Navias told AmericaSpace, “for R&R work in the future.”
A spacewalk so early into a crew’s increment is comparatively rare and only mirrored in recent years by the unscheduled EVA of Expedition 46/47 crewman Tim Kopra, alongside Scott Kelly, within a few days of arriving at the station in December 2015. Yet with eight previous EVAs between them, Feustel and Arnold are both seasoned spacewalkers and NASA has noted that there are “no issues” with sending them outside so soon after their arrival. During the course of the EVA, their Expedition 55 crewmate Norishige Kanai of the Japan Aerospace Exploration Agency (JAXA) will serve as the primary Intravehicular (IV) astronaut, responsible for suiting them up, whilst he and NASA’s Scott Tingle will support Canadarm2 operations throughout the spacewalk.
Feustel, Arnold and Artemyev will therefore be required to hit the ground running when they arrive at the station and are welcomed aboard by the incumbent Expedition 55 crew of Russia’s Anton Shkaplerov, together with Tingle and Kanai. This trio have been in space since mid-December. In early April, the crew will support the arrival of SpaceX’s CRS-14 Dragon cargo ship, the final stages of whose rendezvous and capture will be led by Kanai, backed-up by Tingle, in the station’s multi-windowed cupola. It is expected to be followed by Orbital ATK’s OA-9 Cygnus in early May, SpaceX’s CRS-15 Dragon in early June, Russia’s Progress MS-09 in early July and Japan’s H-II Transfer Vehicle (HTV)-7 in mid-August, producing a busy manifest of visiting vehicles. It remains to be seen if the SpaceX and Orbital ATK craft will see joint berthed operations, with CRS-14 and CRS-15 slated to use the Earth-facing (or “nadir”) port of the Harmony node and OA-9 expected to use Unity nadir. All told, around 250 scientific experiments will be performed during the expedition.
Dovetailed into this plan is the scheduled 3 June departure and return to Earth of Soyuz MS-07 with Shkaplerov, Tingle and Kanai, whereupon Feustel will assume command of the station, beginning Expedition 56. Three days later, Soyuz MS-09 will launch from Baikonur with a new crew—Sergei Prokopiev of Russia, Alexander Gerst of Germany and NASA’s Serena Auñón-Chancellor—who will embark on a two-day rendezvous, before docking at the Earth-facing (or “nadir”) Rassvet module on 8 June.
Two further EVAs are scheduled in the May-August timeframe, the first from the U.S. Orbital Segment (USOS) and the other from the Russian Orbital Segment (ROS). Then, on 8 August, Artemyev—making the third spacewalk of his career—and first-timer Prokopiev will venture outside the station to deploy nanosatellites and install panoramic video cameras. The cosmonauts will also install the Icarus experiment to monitor the flight routes of migratory birds. “These are routine operations,” Artemyev told Tass, “and all cosmonauts can remove and install equipment on the station’s external surface.” Present plans call for Artemyev, Feustel and Arnold to return to Earth on about 28 August, wrapping up an increment of approximately 160 days in orbit.
The three men have been deep in training for more than a year. Feustel was assigned to the crew in January 2017, with the initial expectation that he would join two cosmonauts aboard Soyuz MS-08 for the flight to and from the space station. However, Russia’s 2016 decision to reduce its crew component from three to two—in part due to ongoing problems getting its long-delayed Nauka (“Science”) lab ready to fly—opened up the opportunity for an additional U.S. crew member. In March 2017, NASA assigned veteran astronaut Ricky Arnold to fill the additional U.S. crew position.
After completing their final exams at the Star City cosmonauts’ training center, on the forested outskirts of Moscow, last month, the three men and their backups—veteran Russian cosmonaut Alexei Ovchinin and “rookie” NASA flyer Nick Hague—flew into a snowy Baikonur on 4 March. “Only two backups, since Hague is serving as a backup for both U.S. astronauts,” NASA’s Rob Navias recently told AmericaSpace. “And the Program would evaluate crew complement if they needed to do so.”
The two crews performed fit-checks of their Sokol (“Falcon”) launch and entry suits, inspected the Soyuz MS-08 spacecraft and raised their national flags. “A good day trying out spaceship and spacesuits for size,” Arnold tweeted. Their spacecraft was fueled and filled with compressed gases, then encapsulated in its payload fairing, ahead of integration with the Soyuz-FG booster. This 162.4-foot-tall (49.5-meter) behemoth was rolled horizontally out of Baikonur’s integration hall to the Site 1/5 launch pad on Monday, 19 March. As is traditional, rollout got underway at precisely 7 a.m. local time. “Rocket headed to the pad and upright,” Feustel later tweeted. “@OlegMKS @astro_ricky and I are ready to roll! Two days to liftoff!” Nicknamed “Gagarin’s Start”, Site 1/5 is the selfsame site from which Yuri Gagarin began his pioneering spaceflight, back in April 1961. Paying tribute to tradition, Feustel and Arnold planted trees in the Avenue of Cosmonauts, assisted by Artemyev, who did likewise before his first flight in 2014. “Tree-planting ceremony on a clear, crisp morning,” Arnold tweeted. “The sidewalks here are lined by the trees of those who have gone before us.”
Early Wednesday, the two crews were awakened in Baikonur’s Cosmonaut Hotel. They showered and were disinfected, then submitted to microbial samples in support of the ISS research investigations that they will perform on-orbit. After ceremonially autographing the doors of their hotel rooms and receiving a blessing from a Russian Orthodox priest, they proceeded via bus to Site 254 to don their Sokol launch and entry suits. Here, Artemyev, Feustel and Arnold were screened behind glass, offering them a final opportunity to bid farewell to their families and friends, including photographs with their children.
The prime crew then headed out to Site 1/5, arriving at the launch pad about 25 minutes later. Artemyev was inserted into the center commander’s seat of Soyuz MS-08’s descent module, with Feustel taking up his own position in the Flight Engineer-1 couch on the left-hand side of the vehicle. The final seat, in the right-side Flight Engineer-2 couch, was taken by Arnold.
Already loaded aboard the Soyuz-FG was a highly refined form of rocket-grade kerosene, known as “RP-1”, with liquid oxygen being continuously topped-off until close to T-0, to ensure that boiled-off cryogens were kept replenished and maintained at “Flight Ready” levels. At 10:30 p.m. local time (12:30 p.m. EST), with about 15 minutes to go, the Launch Abort System (LAS) was armed and transferred to Automatic Mode and the crewmen were instructed to close the visors of their space suits.
At T-5 minutes, Artemyev’s controls were activated and internal avionics aboard Soyuz MS-08 were spooled-up to monitor booster systems throughout ascent. From within the control bunker, the “launch key”—an actual, physical key—was inserted to enable the booster’s ordnance. Propellant tanks were pressurized and it was transferred from ground support utilities onto internal power, with the twin umbilical towers retracting away from the vehicle.
Ten seconds before T-0, the turbopumps of the RD-108 first-stage engine and the RD-107 engines of the Soyuz-FG’s four tapering, strap-on boosters attained full speed. Five seconds later, the engines themselves ignited and ramped up to full power, before Site 1/5’s fueling tower retracted and Soyuz MS-08 roared into the Baikonur sky. With the four tapering boosters and the central core powering the initial launch phase, a total of five engines punched out a combined total of 930,000 pounds (422,000 kg) of thrust to lift the 672,000-pound (305,000 kg) rocket away from Earth and onto its 49-hour, 34-orbit journey to reach the space station.
Less than two minutes after liftoff, the strap-on boosters—each of which measures 64 feet (19.6 meters) in length—were exhausted and jettisoned from the stack. By this point, the crew was already traveling in excess of 1,100 mph (1,770 km/h). With the boosters gone, the core continued to burn hot and hard, until the RD-108 burned out at four minutes and 43 seconds after liftoff. At the instant of RD-108 shutdown, the Soyuz-FG and its human cargo had reached an altitude of 105.6 miles (170 km).
Next came the turn of the third stage, which executed a so-called “Hot Stage” burn, igniting its single RD-0110 engine whilst still attached to the core. A few seconds later, the 89-foot-tall (27.1-meter) core stage was jettisoned. The third stage pushed Soyuz MS-08 to a velocity in excess of 13,420 mph (21,600 km/h) and burned for four minutes, until it shut down at eight minutes and 45 seconds into the flight. By the time of RD-0110 cutoff and the separation of the 22-foot-long (6.7-meter) third stage, Soyuz MS-08 had attained a preliminary orbit with an apogee of 143 miles (230 km) and a perigee of 118 miles (190 km), inclined 51.66 degrees to the equator.