The International Space Station (ISS) might not have an immediate replacement once it retires.
NASA's Aerospace Safety Advisory Panel (ASAP) recently warned the space agency of a "precarious trajectory" wherein a replacement for the ISS may not be fully operational or even in orbit at all by the time the aging space station is deorbited, per Space News.
NASA plans to retire the ISS by the end of the 2020s, at which point, the space station would be at least 24 years old.
NASA's 'Precarious Trajectory' Details
At a July 21 meeting, members of NASA's ASAP voiced their concern that the space agency might not have a replacement for the ISS in time for the aging space station's retirement, which could cause a gap in American human spaceflight in low Earth orbit.
To be more concrete, NASA's ASAP is worried that the commercial stations whose development NASA is supporting may not be ready in time to replace the ISS in Earth's orbit.
The development of these commercial stations is also affected by insufficient budgets that could delay their launch, which may exacerbate the gap between the ISS and the US' new space station.
As such, the efforts NASA is doing to switch from the ISS to commercial space stations, the Commercial Leo Earth Orbit (LEO) Destinations, are on a "precarious trajectory" to be realized in time and within the projected resources needed to maintain a NASA LEO presence. This gap between space stations is an area of concern for ASAP, according to its chair, Patricia Sanders.
You may remember that NASA selected two proposals from teams led by Jeff Bezos' Blue Origin and from Nanoracks and Northrop Grumman in December 2021 to give them funding and support to further develop their commercial space stations.
However, NASA plans to issue formal requirements that these space stations are ready to use in late 2024, a plan which may leave Blue Origin and Nanoracks, and Northrop with not enough time to fully develop them, per panel member Amy Donahue.
Read also: ISS Experiments: Here Are What Astronauts in Space Will Work on Next; Cancer Drug Delivery and More
"There is very little margin for ensuring a continuous US presence in LEO is maintained," Donahue said.
She then stated that the current schedule requires speeding up development at a pace faster than any other human spaceflight program since Project Mercury during the space race.
Donahue is concerned about the things NASA might do to mitigate the risk of failing to meet its schedule, which is the panel's concern from a risk perspective.
Another problem is funding. Space.com mentioned in its article that the transition from ISS to commercial stations might not have enough funding to keep them in space.
Donahue, again, said that if interest is low, the space agency may have to find funding to serve as a "bridge" while commercial stations begin operations during the transition period.
She also added that maintaining a continuous human presence in orbit now and into the future will require a "significant government investment."
The First Space Gap
Donahue and Sanders' concerns aren't without merit. NASA suffered its first gap with the retirement of its space shuttles, which NASA used to send astronauts to space in the past.
Astronomy.com stated that the space agency was forced to retire these spacecraft due to high costs, slow turnaround, few customers, and safety problems involving the vehicle itself and NASA at the time.
Unfortunately, when the shuttles were retired in 2012, NASA astronauts were forced to go to space using Russian rockets, which is a situation many were uncomfortable with.
