Hitching a ride to orbit

NASA has relied on Russian spacecraft to transport American astronauts to the International Space Station (ISS) since 2006, but increasing costs — plus political tensions and aging technology — have pushed the U.S. to find new ways to transport crew members.

On April 23, SpaceX launched another crew of astronauts to the International Space Station (ISS), the third successful mission of the commercial crew transport program. Over the past 15 years, NASA has paid Russia nearly $4 billion for seats on their Soyuz rockets, enduring a price tag that increased dramatically after the space shuttles were retired in 2011. With escalating tensions over Russian interference in U.S. elections, and a buildup of forces near the Ukrainian border, there couldn’t be a better time for the U.S. to have its own ride into orbit once again.

The ISS has been gradually built since 1998, with a continuous presence of astronauts onboard for more than 20 years. It was conceived as an orbiting scientific laboratory, and a testing ground for the technologies that will be required for long-term missions to the moon and Mars in the future. Circling the Earth about 250 miles above the surface, it orbits the planet in just over 90 minutes. One section of the ISS is run by the U.S. in collaboration with space agencies from Japan, Europe and Canada, while another section is operated by Russia. The last major component of the U.S. portion was added in 2011, but Russia might expand its side starting later this year. The U.S. plans to continue operating its part of the ISS until at least 2030, while Russia recently announced that it may pull out of the collaboration in 2025 to build its own station.

There were initially only two spacecraft that were certified to bring astronauts and cosmonauts to the ISS, the U.S. space shuttles and Russian Soyuz rockets. In 2003, the space shuttle Columbia disintegrated as it reentered the Earth’s atmosphere, tragically killing all seven crew members. NASA grounded the fleet for more than two years while developing plans to complete construction of the ISS and then retire the shuttles in 2011. Astronauts began flying to the ISS with Russia in 2006, and NASA paid around $25 million per seat during the first five years. But when the shuttles retired and Russia became the only launch provider, the price per seat skyrocketed from $37.4 million in 2011 to $90.3 million in 2020.

“Relying on the Russians for regular transport to the ISS has become increasingly problematic for several reasons,” says Jack Burns, a professor of astrophysics at the University of Colorado who served on NASA’s Advisory Council in the lead up to the retirement of the space shuttle program.

“First, the political situation with Russia is unstable. They could pull the plug at any time and we wouldn’t be able to get our astronauts to the ISS,” he says. “Second, the Russians continue to increase the price per seat. Third, the Russian Soyuz spacecraft is getting quite old. The original vehicle was designed in the 1960s. Safety is becoming a question.”

After the Columbia disaster, NASA initially tried to develop its own partially reusable space capsule called Orion starting in 2005. Several years later, the incoming Obama administration reoriented the Orion program to focus on deep space exploration, and directed NASA to collaborate with commercial partners to ferry astronauts to and from the ISS. Just a few months before the final shuttle mission in 2011, four companies were awarded initial contracts to develop human spaceflight capabilities within five years. At the end of a competition, NASA awarded $4.2 billion to Boeing for development of their Starliner concept, and $2.6 billion to SpaceX for their Dragon capsule. In 2016, both companies announced that their first crewed flights would be delayed until at least 2018.

SpaceX finally launched its first crew of two astronauts to the ISS in May 2020, while Boeing is expected to send their first crew later this year. The SpaceX launch came just five months before NASA purchased its final $90 million seat on a Russian Soyuz rocket, which was quickly followed by a second SpaceX launch sending a full crew of four to the ISS. The third SpaceX launch last week marks the beginning of a busy year of crew rotation at the ISS, with an additional SpaceX flight scheduled for October and the initial Boeing flights slated for September and December. It’s more traffic than is necessary to keep the ISS packed with astronauts, but NASA wants to avoid relying on a single company for future flights, even if one of them is clearly more reliable and cost effective.

“SpaceX has pioneered recovery and reuse of the first stage of their Falcon rocket. The first stage engines are the most expensive part,” Burns explains. “In principle, reuse can lower the cost of access to space. Just by creating this new competitor, SpaceX is forcing the cost of all launches to decline.”

The future of the ISS may be similar to the development of commercial spacecraft over the past decade. By 2030, NASA intends to provide funding for companies to develop new space stations that might complement or eventually replace the ISS. There are already several companies with concepts for commercial space stations, ranging from an updated version of the ISS with modern interiors designed by French architect Philippe Starck, to inflatable habitats that could herald the debut of orbiting hotels for space tourists. If there’s one thing NASA has learned from the commercial crew program, it’s that such concepts will likely require more time and funding to develop than anticipated. Starting these projects now will ensure an uninterrupted human presence in orbit, far beyond the expected lifetime of the ISS.

Travis Metcalfe, Ph.D., is a researcher and science communicator based in Boulder. The Lab Notes series is made possible in part by a research grant from the National Science Foundation.