U.S. boosts ISS for the first time without needing Russia to help

The International Space Station (ISS) periodically requires boosts from external spacecraft to help it maintain its orbit.

The ISS weighs 444 tonnes and continues to expand, while orbiting at an altitude of about 250 miles (400 kilometers). However, atmospheric drag brings the space station closer to Earth by about one mile (1.6 kilometers) each month, and consequently, it needs to be lifted back up.

The task is currently Russia's responsibility, for which they use the thrusters on the Progress cargo spacecraft and the ISS' Zvezda module. However, Russia's future with the ISS is unclear, with the nation potentially withdrawing from the space station in 2024 despite NASA's commitment to keep it operational until 2030. Therefore, the remaining countries need a way to manage the space station responsibilities currently left to Russia.

As such, the United States has now used Northrop Grumman's upgraded Cygnus cargo spacecraft for the first time to boost the ISS back to a higher orbit on June 25th, 2022. This is the first time the U.S. has been able to do so without Russian help since retiring the Space Shuttle.

"This reboost of the ISS using Cygnus adds a critical capability to help maintain and support the space station. It also demonstrates the enormous capability Cygnus offers the ISS and future space exploration efforts," said Steve Krein, vice president, civil and commercial space, tactical space systems, Northrop Grumman.

"Experience gained by the Cygnus program is also being applied to other Northrop Grumman human space programs. Cygnus is the basis of the Habitation and Logistics Outpost, or HALO, the first module planned for NASA's Lunar Gateway which will orbit the moon and serve as a staging point for exploration of the lunar surface and enable future exploration beyond the moon," Krein continued.