The last month has been an eventful one for the Expedition 71 crew on the International Space Station and their two helpers from the Starliner Crew Flight Test (CFT). It is still not known when – or even if – CFT will return to Earth with crewmembers Butch Wilmore and Suni Williams, two veteran astronauts and test pilots that have been in space well beyond the initial duration of eight days envisaged when they launched into orbit on June 5.
NASA is now openly talking about the contingency options, which includes potential options involving SpaceX’s Dragon spacecraft, should the Agency decide Starliner will undock without its crew.
For the last 62 days, the ISS has had nine crew members aboard instead of its usual seven. The CFT crew’s assistance has helped the Expedition 71 crew with its regular tasks, but the extra crew members can also consume more oxygen and other resources. While various return scenarios for Starliner Calypso are being discussed, Crew-8 is preparing to leave the Station and Crew-9 is preparing for flight.
The combined crews of Expedition 71 and Starliner CFT pose aboard ISS. (Credit: NASA)
STARLINER
The Starliner CFT mission’s extended stay at ISS has made headlines and dominated discussion on the ground. Shortly after Calypso docked to the Station, the mission was extended, first by one week, then another, and then longer than that. During the first days of the flight, NASA did state that the flight could be extended based on test objectives.
The initially planned return date of June 14 was first moved to June 18, so that more checkouts could be done on Starliner and the Expedition 71 crew could focus on spacewalk preparations. Calypso’s return was moved to June 22 to perform a hot-fire test on seven aft thrusters as well as additional testing and checkouts.
Starliner Calypso firing its thrusters during an on orbit docked test. (Credit: NASA)
The June 22 date did not hold, and neither did a new date of June 26. According to NASA, canceling the June 26 date was to allow for more data review of Calypso’s propulsion system as well as to deconflict the Starliner undocking from planned spacewalks. NASA Commercial Crew Program manager Steve Stich stated “We are letting the data drive our decision making relative to managing the small helium system leaks and thruster performance we observed during rendezvous and docking.”
As return dates came and went, and as June turned into July, there was some discussion as to what was happening with Calypso and what the path forward might be. Updates from NASA and Boeing were sparse while sensational headlines concerning the mission were showing up in news reports. On the ground, tests were being conducted at White Sands in New Mexico related to issues with Calypso’s propulsion system.
A Starliner thruster being tested at White Sands. (Credit: NASA)
During a NASA press conference on July 25, Steve Stich and Boeing’s Mark Nappi discussed preliminary test results and the forward plan for additional testing. The thruster tests, which concluded on July 18, found that there was degradation of seals in the propulsion system due to exposure to nitrogen tetroxide propellant vapors, and the thruster performance closely replicated what happened on orbit. No new return date for CFT was announced, though Starliner had earlier been cleared for an emergency return home with crew if needed.
Two days later, Starliner Calypso conducted a test firing of 27 of the spacecraft’s 28 thrusters while docked to the Station. As of the time of writing there is still no return date for the CFT mission, and the results of this on-orbit test are being evaluated.
At the beginning of August, Boeing stated that they remained confident in Starliner and its ability to return safely with crew while also supporting NASA’s requests for additional data. CFT was initially estimated to be able to stay on orbit until mid-August if needed.
CFT astronauts Butch Wilmore and Suni Williams posing with Expedition 71 astronauts Tracy Dyson and Michael Barratt during EVA preparations. (Credit: NASA)
The latest news conference on August 7 openly spoke about the potential options including SpaceX’s Dragon, revolving around the delay to Crew-9’s launch. Although no decision has been made, should Starliner return without its crew, options including keeping Suni and Butch on the ISS until February 2025.
Roundup of today's @NASA Teleconference about @Space_Station Operations and @BoeingSpace's Starliner CFT mission:
Crew-9
– NASA has set up the Crew-9 Dragon to have the flexibility to launch with 2 astronauts, and return with 4 in Feb 2025; SpaceX Suits for Butch & Suni are… https://t.co/crnsFQq3Ke— Ryan Caton (@dpoddolphinpro) August 7, 2024
Numerous evaluations are still taking place, and NASA administrator Bill Nelson will make the final decision.
EVA ISSUES
Three EVAs had been scheduled for Expedition 71 this summer, but none of them have taken place so far due to spacesuit issues. EVA-89, on Nov. 1, 2023, was the last US segment spacewalk that was successfully completed. Astronauts Jasmin Moghbeli and Loral O’Hara removed a fixture on the S4 truss to prepare it for a future solar array upgrade. The duo also removed and replaced a trundle bearing on the port solar alpha rotary joint.
Moghbeli and O’Hara also removed clamps on an S-band Antenna Subassembly on an external stowage pallet. However, they had issues removing the covers from this antenna and could not complete the removal of a faulty radio frequency group electronics box. The task was deferred to EVA-90, where astronauts would finish the removal of the box for a return to Earth in the future.
Astronaut Matthew Dominick during a pre-breathe exercise prior to the planned EVA-90 on June 13. This EVA was subsequently called off. (Credit: NASA TV)
EVA-90 was scheduled for Thursday, June 13 with astronauts Tracy Dyson and Matthew Dominick. Dyson and Dominick would be tasked with finishing the deferred radio frequency group removal as well as collecting microbial samples from the exterior of the Station on the Destiny and Quest modules. A third task would involve preparing a wrist joint on the Canadarm2 robotic arm for a future installation as a replacement part.
However, this EVA was postponed due to what NASA termed a “spacesuit discomfort issue”, without providing details, presumably due to astronaut medical privacy. Matthew Dominick was replaced by Michael Barratt as EV2 – with Tracy Dyson as EV1 wearing the red stripes – and the EVA was rescheduled to Monday, June 24.
Astronaut Mike Barratt working on spacesuit equipment. (Credit: NASA)
On that day, astronauts Dyson and Barratt successfully donned their spacesuits and depressurized the airlock. However, the spacewalk ended after just 31 minutes due to a water leak in the cooling and umbilical unit of Dyson’s spacesuit. A second spacewalk – EVA-91 – to complete several tasks including preparing the Alpha Magnetic Spectrometer for an upgrade, had been scheduled for July 2 but also needed to be pushed back.
The next EVA was initially rescheduled to the end of July to better understand and troubleshoot the water leak issue in the aging shuttle-era spacesuit, but it still has not taken place. These spacesuits are due to be replaced by a new suit under development, but in late June contractor Collins Aerospace pulled out of two Exploration Extravehicular Activity Services task orders to develop this suit.
The prototype of a planned new spacesuit for low-Earth orbit operations. (Credit: Collins Aerospace)
A NASA press release stated that Collins Aerospace and NASA mutually agreed to the descope due to the suit’s development timeline being incompatible with the ISS schedule or NASA’s objectives. The company will still support the EMU suits aboard ISS as part of the existing Extravehicular Space Operations Contract.
Collins Aerospace absorbed Hamilton Standard, the contractor that developed the life support system of the Space Shuttle’s Extravehicular Mobility Unit (EMU), now used on ISS.
The S.S. Patricia Hilliard Robertson is firing its engine to boost the International Space Station’s altitude in May 2024. (Credit: NASA)
DAILY OPERATIONS AND POTENTIAL DEBRIS ENCOUNTER
While Starliner and spacewalk issues dominated the news being reported about the Station, daily activities continued as usual aboard the large orbiting complex. Expedition 71’s crew was busy with experiments as well as regular housekeeping and maintenance, and they were ably assisted by the Starliner crew.
The Station’s crewmembers also needed to prepare for an encounter with space debris. Around 00:45 UTC on June 27, Mission Control asked the ISS crew to “shelter in place” aboard the spacecraft they flew aboard – including Starliner – due to the breakup of the Russian RESURS-P1 satellite near the Station’s altitude earlier in the day. All crewmembers were cleared to resume normal activities aboard the orbiting complex around an hour later.
Cygnus NG-20 S.S. Patricia “Patty” Hilliard Robertson just before its release from ISS. (Credit: NASA)
On Friday, July 12, the Canadarm2 released the Cygnus S.S. Patricia “Patty” Hilliard Robertson after unberthing it from the Station’s Unity node module. The Cygnus was loaded with trash and discarded gear along with the KREPE-2 reentry experiment from the University of Kentucky. The Cygnus completed a destructive reentry to end its flight the following day to end the NG-20 mission.
The ISS got another Cygnus visitor on Tuesday, August 6 when the NG-21 S.S. Francis R. “Dick” Scobee successfully conducted a rendezvous to the Station before being berthed by the Canadarm2 operated by Matthew Dominick. S.S. Francis R. Scobee, berthed at the Unity module’s nadir port, joins Starliner Calypso, Crew Dragon Endeavour, Soyuz MS-25, Progress MS-26, and Progress MS-27 as the Station’s current visiting vehicle complement.
Current visiting vehicle complement and locations on ISS. (Credit: NASA)
The ISS, as humanity’s premier microgravity laboratory, hosts many science experiments. The Expedition 71 and CFT crewmembers have conducted research on production of orbital fibers in microgravity, cataloging the microbial species in the Station’s water system, 3D printing in microgravity, hydroponics, heart adaptation in microgravity, and many other experiments.
Astronauts Wilmore and Williams were instrumental in enabling science to continue while other astronauts were busy with things like packing the NG-20 Cygnus spacecraft prior to departure.
Crew Dragon Endeavour with the Milky Way in the background. (Credit: NASA)
PLANS IN FLUX
While normal activity continues aboard the Station, the CFT crewmembers are not the only ones that are spending extra time on orbit. Crew-9 was originally supposed to fly on Sunday, Aug. 18, but has now been delayed by over a month. The new launch date is no earlier than Sept. 24 and the flight will now lift off from SLC-40 at Cape Canaveral Space Force Station rather than Pad 39A as had been planned.
NASA cited the need for “operational flexibility” in its announcement of the flight’s delay. The agency wants to finalize return planning for CFT, and to deconflict the handover between the Soyuz MS-25 and MS-26 missions. Soyuz MS-26 is scheduled to launch on Sept. 11 at 16:22 UTC with Roscosmos cosmonauts Alexey Ovchinin and Ivan Vagner along with NASA’s Don Pettit.
Starliner Calypso docked to ISS with the aurora australis in the background. (Credit: NASA)
Teams are analyzing the results of recent tests on Starliner, working on flight rationale for the Starliner’s propulsion system, and checking on systems reliability. This delay also gives NASA time to reconfigure Crew-9’s Crew Dragon Freedom if needed for any contingency plan, though nothing has been decided regarding whether Starliner Calypso would return to Earth with crew.
This summer has also seen the naming of a new crew as well as a shuffling of future crewed flights to ISS from the United States. Crew-10, to fly aboard a new Crew Dragon – which the astronauts will name – is scheduled to fly no earlier than February 2025, a slot that had been previously reserved for Starliner-1.
Crew-10 from left to right: Nichole Ayers, Kirill Peskov, Anne McClain, Takuya Onishi. (Credit: NASA/James Blair)
NASA astronauts Anne McClain and Nichole Ayers, JAXA astronaut Takuya Onishi, and Roscosmos cosmonaut Kirill Peskov are to fly to the ISS on this mission, while Starliner-1 has been pushed back to no earlier than August 2025. Starliner-1, to be crewed by NASA’s Scott Tingle and Mike Fincke, CSA’s Joshua Kutryk, and JAXA’s Kimiya Yuri is to be the first operational mission of that spacecraft, and when – and maybe even if – it flies will depend on the ultimate performance of the CFT mission.
In the nearer term, Progress MS-28 is scheduled to fly to the Station with a launch on Thursday, Aug. 15 at 03:20 UTC from Baikonur. This robotic spacecraft is scheduled to fly fuel, water, and cargo to ISS and will dock with the Russian segment. MS-28 is the third Progress mission to fly to ISS this year.
Progress MS-26 arriving at the ISS over a cloudy Earth. (Credit: NASA)
Progress MS-26 is scheduled to undock from the Station’s Russian segment on Tuesday, Aug. 13 at 02:03 UTC, while Progress MS-28 is scheduled to dock on Saturday, Aug. 17 at 05:56 UTC. MS-26 will conduct a destructive reentry to Earth after being loaded with trash, while Progress MS-27 remains docked to the Station.
The EVA schedule aboard the Station is also still in flux. While the US segment EVAs set for this summer are reshuffled, planning and work for them continues. The NG-21 Cygnus mission flew 43 kg of spacewalk equipment which is now at the ISS, while work continues to resume spacewalks. No Russian segment EVAs are currently scheduled.
Cygnus NG-21 S.S. Francis R. “Dick” Scobee just after being grabbed by the ISS Canadarm2. (Credit: NASA TV)
Crew-8’s departure from the Station is highly dependent on what decisions ultimately are made with Starliner Calypso and the CFT return. Their departure also depends as well as when Crew-9 finally gets off the ground and on any changes that may be made to the mission.
Crew-8 NASA astronauts Matthew Dominick, Michael Barrett, and Jeanette Epps as well as Roscosmos’ Alexander Grebenkin stand to get at least a month of additional time on orbit – and perhaps even longer. Decisions will be made in the coming weeks that could reshuffle crew planning and Station activities to a much greater degree than at present.
(Lead image: Starliner Calypso docked at the Harmony module on ISS on July 3, 2024. Credit: NASA)