NASA plans to leave ISS to focus on future Mars mission

NASA has been involved with the International Space Station since the beginning some 15 years ago, but that association may be coming to an end. NASA’s chief of human spaceflight, William Gerstenmaier explained at a recent meeting that the agency plans to “get out of ISS as quickly as we can.” This by no means points to a scaling back of NASA’s human spaceflight. Rather, it’s the beginning of humanity’s return to the moon and beyond.
One of NASA’s main goals for the long term is a manned mission to Mars, but there are a lot of technologies and strategies that need to be developed first. Focusing on the Moon first will let NASA prepare for the Mars mission. It’s unclear if a lunar landing is in the cards, but the space agency does intend to send astronauts to lunar orbit (sometimes called cislunar space). Astronauts would be considerably farther from Earth and exposed to more radiation than they are on the ISS. This would be an important test for a Mars mission, which would likely include years of living outside Earth’s protective cocoon.
The problem is money. NASA doesn’t have enough of it to continue taking a leading role in low-Earth orbit operations and still fund missions to the Moon and Mars. In 2015, NASA spent about $3 billion on ISS operations, which amounts to 20% of its entire budget. That’s expected to rise to $4 billion by 2020. The agency pays for transport of its own supplies to and from the ISS, but also experiments run by private companies. Astronauts aboard the station also spend time on these projects on NASA’s dime.

NASA is currently committed to support the ISS until 2024 or 2028 at the latest. At that point, the ISS would be nearing the end of its useful life, and NASA will be be faced with either developing an expensive replacement or moving on to bigger things. It’s choosing the latter and leaving low-Earth to private spaceflight — or at least that’s what everyone hopes will happen.
Having a presence in orbit of Earth is important for basic space research, and also as a stop-off for missions heading deeper into space. Any private station would undoubtedly be much more modest than the $140 billion ISS, but even building a smaller station is expensive. China expects to have a permanent station in orbit by 2020, which could take over for some ISS responsibilities.
Gerstenmaier sees this announcement as a warning to private space firms. They’ve got a decade to commercialize low-Earth orbit before NASA moves on. But what will become of the ISS? When the time comes, it’ll probably be deorbited over the Pacific to burn up harmlessly. NASA hopes there will be a new commercial station in the works to see it off.