NASA plans ‘continuous heartbeat’ in space after ISS retires

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

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

The key to these missions is the human part. “As it transitions from (the ISS) to future commercial space stations, NASA will maintain a constant and continuous presence in low Earth orbit,” the report said. “This continuous rhythm of human activity will allow NASA to reduce the risk of sending humans to Mars, preserve critical operational skills, maintain a stable transportation rhythm, continue to advance science and maintain engagement with commercial and international partners .”

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

Companies like Axiom Space, Blue Origin and Northrop Grumman hope to replace the ISS with their own versions, but they probably won’t be ready for five years. Instead, NASA’s strategy for these 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 conducting scientific research in the microgravity environment, as well as research that relates to human health in space, in preparation for future missions to the Moon and Mars.

“Through the (ISS), NASA has demonstrated that the study of microgravity is critical to advancing both knowledge about us and our planet,” the report said. “As we approach the transition from the space station to commercial platforms in low Earth orbit, NASA must enable the government to use these platforms to further research and development across a range of national goals that strengthen economies and improve the quality of life here on Earth for all people.”

The new strategy also emphasizes 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 for Boeing’s Starliner program after its failed test flight this year.

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