NASA Solidifies Planning to Deorbit ISS in 2031

NASA Solidifies Planning to Deorbit ISS in 2031

A month after formally announcing plans to extend operations of the International Space Station to 2030, NASA is making clear that is the end of the road. A new update to its ISS transition plan spells out how that end will play out, with the orbit gradually lowered until the football-field size facility reenters and any surviving pieces fall into the Pacific Ocean in January 2031. After that, NASA will buy whatever human spaceflight services it needs in low Earth orbit from companies expected to be operating their own space stations by then.

In the 2017 NASA Transition Authorization Act (P.L. 115-10), Congress required NASA to submit a transition plan explaining how it will meet its needs for human spaceflight research in LEO after ISS ends. For years the agency’s goal has been to facilitate the emergence of a commercial LEO economy that includes privately built and operated space stations with NASA as one of many customers using them instead of building another government-owned facility.

The law called for the first transition report in December 2017 with updates every two years through 2023. The original version was released a little late, on March 30, 2018, and this one, issued January 31, is NASA’s first update, almost four years later.

A mosaic of the International Space Station using images taken by the departing Crew-2 crew on SpaceX’s Crew Dragon Endeavour on November 8, 2021. Credit: NASA

A lot has happened in between affecting NASA’s future human presence in LEO as the agency shifts its focus to returning astronauts to the Moon and going on to Mars.

For example, in 2020 SpaceX’s Crew Dragon restored the U.S. capability to launch people into orbit after nine years of dependence on Russia following the end of the space shuttle program. In 2021, ISS celebrated 21 years of permanent human occupancy, a testament to the strength of the partnership among the United States, Russia, Japan, Canada and 11 European countries that has weathered dramatic terrestrial geopolitical changes so far unscathed. Over the past several years, NASA has embraced public-private partnerships for a wide range of human spaceflight activities including successors to ISS. It signed a contract with Axiom Space in 2020 to add a commercial module to the ISS that later will detach and become a free-flying facility, and just two months ago chose three companies, Blue Origin, Nanoracks, and Northrop Grumman, to design commercial space stations for its Commercial LEO Destinations initiative.

The updated transition report works from the assumption that ISS will last until 2030, hopefully giving one or more of those companies enough time to design, build and launch something to replace at least some of its capabilities.

In the 2017 law, the United States committed to operating ISS at least through 2024. Congressional attempts to pass a new NASA authorization bill and extend that to 2030 have not succeeded, but on December 31, the Biden Administration gave its approval to do just that. A White House commitment isn’t quite as solid as a law, but it is enough for negotiations with the other partners to commence in earnest to get their agreement.

But the ISS is old. The first modules were launched in 1998. The updated transition report asserts the U.S. On-Orbit Segment (USOS) and the Functional Cargo Block (also known as FGB or Zarya), which was built by Russia but at U.S. expense and thereby counts as a U.S. module, are in good enough shape to make it to 2030. The report says Russia has certified the modules it owns through 2024 and “will begin work on analyzing extension through 2030.” Nagging leaks in one part of the Russian segment so far have thwarted attempts to seal them. NASA and its Russian counterpart, Roscosmos, insist they pose no danger to the crew, but if nothing else they illustrate the aging problem.

Former NASA Administrator Jim Bridenstine warned the Senate Commerce, Science, and Transportation Committee last October there is no guarantee the ISS will make it 2030, pushing back on the notion that it might last even longer.

NASA’s bottom line in this report is that “While the ISS will not last forever, NASA expects to be able to operate it safely through 2030.”

Then it will be deorbited. This report lays out that end-of-life process in more detail than in the past. Notionally three Russian Progress cargo spacecraft will be used to lower the ISS’s altitude until it reenters through the Earth’s atmosphere. Reentry is nominally targeted for January 2031 with any pieces that survive the fiery trip falling into the South Pacific Uninhabited Area around Point Nemo.

At 420 Metric Tons, ISS will be the largest structure to make a reentry. Russia’s Mir space station, which operated from 1986-2001, was about 130 MT when it made a controlled reentry into the Pacific on March 23, 2001. The first U.S. space station, Skylab, hosted crews in 1973 and 1974. The approximately 72 MT spacecraft made an uncontrolled reentry in 1979 spreading debris over western Australia and the Indian Ocean. Other space stations launched by the Soviet Union prior to 1986 and more recently by China that have reentered were smaller, though some were still quite sizeable. No one has been injured in any of these reentries.

Not only is ISS old, but it is expensive to operate, about $3 billion a year for NASA. That is another motivation for terminating it although NASA will still need to pay companies to use their facilities.

Congress asked NASA to provide cost estimates in the transition plan for operating the ISS through 2024, 2028 and 2030. In the 2018 report, it showed specific costs for Operations and Maintenance (O&M), research, crew and cargo, and labor and travel.

Budget estimate for ISS through 2030. 2018 ISS Transition Report. Source: NASA

This time it does not give any detail, showing only a “sand chart.”

Budget estimate for ISS through end of life in 2031 plus two years of subsequent commercial LEO services. 2022 ISS Transition Report. Source: NASA

NASA declined to provide any more information, telling by email that “the detailed numbers are not available for public release as they are pre-decisional and procurement sensitive.”

Congress asked NASA to provide an estimate of the deorbit costs and while that item is included in the sand chart, its corresponding monetary value is obscure.

Similarly, the amount of annual cost savings NASA expects to realize by terminating ISS and shifting to commercial services is difficult to quantify based only on that chart. However, Phil McAlister, Director of NASA’s Commercial Spaceflight Division, told a NASA advisory committee meeting on January 19 that NASA estimates it will be about $1.3 million in 2031, the first year, and “if all things go as planned, it will go up to as high as $1.8 billion.”

Getting from here to there will require NASA funding to encourage the commercial sector to invest. After two years of providing only one-tenth of the $150 million requested by the agency for the Commercial LEO Development (CLD) program, Congress appears poised to support it more robustly this year.

NASA requested $101 million for FY2022. In July, the House Appropriations Committee included $45 million for CLD in the FY2022 Commerce-Justice-Science bill that funds NASA. While less than half the request, it is almost three times the $17 million appropriated in FY2021. In October, the Senate Appropriations Committee approved the full $101 million noting NASA had “finally” offered a rationale and roadmap for the program.

Further action on FY2022 appropriations remains stalled, however. NASA is operating under a Continuing Resolution (CR) that holds the agency at its FY2021 level for now.

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