NASA has laid out plans for their future utilization of the International Space Station (ISS) over the next decade, including upgrades scheduled to be conducted on the outpost in the near term, its future use as an analog for human exploration missions beyond Earth Orbit, and the commercial expansion to the orbital outpost.
In the near term, the Station should see the end of the drawn out battery replacement process. For over three years, the batteries located on the Station’s Integrated Truss Structure (ITS) have been systematically replaced and upgraded, which has seen the old Nickel-Hydrogen (NiH2) batteries on the S4, P4 and P6 truss segments of the outpost replaced with newer Lithium-Ion (Li-Ion) batteries.
The first spacewalk to conduct these replacements, US EVA-38, was done by NASA astronauts Shane Kimbrough and Peggy Whitson on 6 January 2017. Since then, ISS crews have worked tirelessly to continue these replacements, notably the Expedition 61 crew, who performed five spacewalks in support of this task.
The final set of NiH2 batteries, located on the S6 truss segment, will be replaced over a series of four spacewalks carried out by Expedition 63 Commander Chris Cassidy and SpaceX Demo-2 Joint Operations Commander Robert Behnken no earlier than June of this year. The extension of SpaceX’s Demo-2 mission was, in part, to allow the crew to take part in these spacewalks.
Also, Cassidy and Behnken will be focused on installing new equipment onto the European Space Agency’s Columbus module.
The duo will prepare Columbus for the installation of Bartolomeo, a European exposed experiment platform built by Airbus which is planned to act as a platform for hosting experiments and other pieces of equipment operated by all kinds of institutions and private organizations.
The fifth spacewalk will also install the Columbus Ka-Band (COL-Ka) Terminal onto the module. COL-Ka, developed by MDA Space and robotics alongside ESA and its partners, will upgrade the communication systems on Columbus to a Ka-Band frequency (between 26.5 and 40 GHz) and allow communication with European Data Relay System (EDRS) satellites in geostationary orbit.
This will allow for much faster communications with the European laboratory and ground stations located on Earth.
While all five spacewalks will be performed by Cassidy and Behnken, Demo-2 spacecraft commander Douglas Hurley will act as IV for all of the excursions, supporting the spacewalks from inside the station and controlling the robotic systems.
During the presentation to the NASA Advisory Council, Shireman also pointed out another spacewalk scheduled for September, although without an exact mission duration for Demo-2 (potentially up to 119 days), it is unknown if Behnken and Hurley will still be on the Station to support the spacewalk.
Looking to the future, the overview to the advisory council promoted the Station’s role in NASA’s long-term future in deep space.
Although most of the focus in NASA’s exploration plan is on the American return to the lunar surface with the Artemis Program, the administration has already set its sights set on a future goal, that being Mars.
NASA and its Human Research Program (HRP) are planning for a series of extended flights to the ISS that will simulate the transit time to Mars.
The agency plans to fly ten ‘year-long’ flights to the Station starting in 2021. These missions will help researchers gain a better understanding of how a prospective flight to Mars would effect the human body and what can be done to mitigate the negative effects.
So far, little information has been provided on these upcoming flights, including crew assignments, launch dates, and what spacecraft will be utilized. But NASA did confirm early overall flight plans and that coordination is ongoing with Roscosmos, who have so far declined to fly any more missions extended beyond the usual six months.
The only dedicated year-long flight to the ISS was the 340 day flight performed by NASA astronaut Scott Kelly and Roscosmos cosmonaut Mikhail Kornienko, who remained on the Station from March 2015 to March 2016. Christina Koch’s recent 328 day flight was the result of a last minute extension and was not planned to last a year originally.
“So far we have an N of 1,” said Shireman, referring to only a single official one year mission having been carried out. “We really need to be having an N of 10 or 12” to get to data on how a year plus in space affects humans, he added.
Also part of the Mars analog program, the agency is preparing to add communication delay and on-orbit medical exercises to the crew’s activities in the years to come.
NASA has had the capability to carry out comm delay activities (where the communications between the ISS crew and ground control would be manually delayed several minutes each way to simulate the time delay that would occur on deep space missions.) since Fall 2019 and could begin as earlier as late 2020.
A decision whether to begin this year is expected in the September-October timeframe.
If NASA decides to implement this, communication delay periods will last from one day to two weeks.
Another important aspect of a deep space travel analog will be on-orbit medical exercises. With a deep-space mission, astronauts would not be able to simply return to Earth as soon as a serious medical issue is detected, as has been done in the past, notably with the Soviet Soyuz T-14 mission to the Salyut 7 space station which returned to Earth 64 days into a six month mission after the commander fell seriously ill.
The problem here is that NASA and its partners don’t know how to deal with too many serious medical issues on-orbit, as demonstrated earlier this year when the University of North Carolina published an article surrounding an event in 2018 when an astronaut two months into a six month mission to the ISS discovered a Deep Vein Thrombosis (a blood clot) in one of their Jugular veins in their neck.
Luckily, NASA and its medical partners were able to tele-medically treat the astronaut’s blood clot and no early return was necessary, although it was considered. The anomaly in 2018 highlighted the issue of a similar event occurring on a future deep space mission where astronauts will be essentially on their own with no possible quick return to Earth and a communications delay factoring in.
NASA plans to carry out a series of medical exercises with future Station crews and ground control teams to build experience and learn more about these kinds of practices. The agency plans to ramp up these activities fast, with four, one to two day long full-fledged on orbit medical situation simulations starting in 2021.
Finally, the commercial expansion of the US Segment of the ISS was also mentioned. On 27 January 2020, NASA announced they had given the Houston-based Axiom Space, Inc. permission to use the forward docking port of the US Segment’s Node 2 “Harmony” module on the Station.
The Axiom Segment will allow the company to support a wide range of commercial ventures, including space tourism, technology demonstrations, and on-orbit manufacturing. Axiom has already signed a deal with SpaceX for at least one commercial Crew Dragon flight, which will ferry one astronaut and three commercial spaceflight participants to the ISS for an eight to ten day flight sometime in 2021.