NASA envisions a “continuous beat” in space after the retirement of the ISS

The International Space Station (ISS) has served as home to astronauts for nearly 30 years, but the aging spacecraft is set to retire at the end of the decade, leaving a huge gap in low Earth orbit. NASA hopes to fill that gap with a commercial version of the ISS. Until that happens, however, the space agency is determined to maintain the human presence in the microgravity environment to stay on track to land astronauts on Mars.

NASA released the final version of its “Microgravity Orbit Low Earth Strategy”, which highlights the need to send long-term human missions into space after the retirement of the ISS. The space agency called its strategy “continuous heartbeat,” a seemingly odd choice of words to convey the need for “long-duration flights of six months to a year to mitigate risks for future trips to Mars.” , wrote NASA. “Flights from 30 days to six months also have limited value,” the space agency added.

The key to these missions is the human part. “While transitioning from the (ISS) to future commercial space stations, NASA will maintain a consistent and continuous presence in low Earth orbit,” the report read. “This uninterrupted pace of human activity will allow NASA to reduce the risk of sending humans to Mars, preserve critical operational skills, maintain a stable transportation cadence, continue to advance science, and support the engagement with commercial and international partners.

NASA and its partners plan to retire the ISS by 2030; the space station is destined for a fiery re-entry through Earth’s atmosphere where most of it will burn up. In 2021, the space agency created its Commercial Low Earth Orbit Destinations program to build a replacement in the coveted spot left by the ISS. NASA, however, is no longer in the business of building space stations. Instead, he just wants to be a customer, helping his business partners build and operate a space station that their astronauts can use.

Companies like Axiom Space, Blue Origin and Northrop Grumman hope to replace the ISS with their own versions, but those probably won’t be ready in five years. Instead, NASA’s strategy for those gap years is to maintain a continuous human presence in space through long-duration missions to destinations in low Earth orbit using commercially owned spacecraft. The main purpose of the missions will be to continue to carry out scientific research in the microgravity environment, as well as research that affects human health in space to prepare future missions to the Moon and Mars.

“Through the ISS, NASA has demonstrated that research in microgravity is critical to advancing our understanding of ourselves and our planet,” the report read. “As we approach the transition from the space station to commercial platforms in low Earth orbit, NASA must allow the government to use these platforms for further research and development across a spectrum of national objectives that enhance the economy and improve the quality of life here on Earth for all people.”

The new strategy also highlights the need for a “diversity of suppliers,” suggesting that NASA wants to rely on more than just SpaceX to transport its crew and cargo to low Earth orbit. The space agency is still in the certification process of Boeing’s Starliner program after its botched test flight this year.

The retirement of the ISS, and the subsequent transition phase, reflects NASA’s own transition to rely on its commercial partners to maintain its presence in space.