2/23/2024 - Written By Caleb Henry
At least six commercial space station efforts are under way to replace the International Space Station by 2031. NASA and other space agencies (but mostly NASA) have spent more than $150 billion on the ISS, the oldest parts of which have been in space for 25 years.
A key trend has emerged among commercial space station hopefuls, one amplified by Sierra Space’s recent graphic showing three different space station sizes – two of which have more volume than the entire 43-part ISS.
One reason for the ISS’s high costs is the use of NASA’s Space Shuttle, which had a 4.6-meter-wide payload bay. That contributed to the need for multiple launches to build out the station. Proposed commercial space stations have larger diameters – 7 meters for Sierra Space’s Life 2.0, 7.6 meters for Gravitics’ Starmax, and 8 meters for Starlab from Airbus/Voyager.
With these large diameters, space station hopefuls aim to deploy systems that offer one-third or more of the ISS’s pressurized volume (900 cubic meters) in a single launch. Starlab targets ~33% of the ISS’s volume with one module, Gravitics targets 40%, and Sierra Space ranges from ~30% to 600% depending on Life module variants. Axiom and Vast also have plans for a large space stations, though sizes haven’t been disclosed. And SpaceX’s Starship, already a large vehicle, could double as a voluminous space station itself.
These future space stations largely depend on heavy lift vehicles with big payload fairings (Starship and maybe New Glenn), showing how these vehicles could usher in a new era of lower cost space stations. Of course, Congress and NASA need to commit reasonable funding to ensure the viability of one or more stations. The agency spends ~$3 billion a year on the ISS, but only $224 million was allocated in FY23 for Commercial LEO Destinations (CLD), the space station replacement program. Emerging commercial space stations stand to be much cheaper than the ISS, but their success at this stage of development hinges on NASA as both an anchor customer and financial backer.
SOURCE: https://twitter.com/SierraSpaceCo/status/1759956031155671078