Two NASA astronauts are currently outside the ISS, repairing an X-ray telescope

By Georgina Torbet Published January 16, 2025

Two NASA astronauts are currently performing a spacewalk, having headed outside of the International Space Station (ISS) at 8:01 a.m. ET this morning, Thursday, January 16. They are on a job expected to last for around six and a half hours, working to repair an X-ray telescope fitted to the exterior of the station called NICER (Neutron star Interior Composition Explorer).

The astronauts are Nick Hague and Suni Williams, and they are performing NASA’s first spacewalk in more than six months, following a suspension of spacewalk activities after a leak problem with a spacesuit in June 2024. With no problems with the suits thus far, Hague and Williams have been performing work to install special patches to the telescope. These patches will prevent too much light from entering the telescope and disrupting its readings, and they will cover over areas of the existing light filter which has been damaged.

On social media, representatives for NASA thanked the pair for their work in repairing the telescope, which is used to investigate very dense objects called neutron stars by observing X-rays, and which has previously produced a stunning map of the sky showing X-ray sources as seen from the ISS.

With some checking and calibration work to perform, NICER should be back to taking science observations soon.

The patches for our NICER telescope have been installed thanks to @NASA_Astronauts Nick Hague!

The next steps for the NICER team include unstowing the telescope and restarting daytime observations to examine the data with the patches installed. Stay tuned for updates. pic.twitter.com/JhFgskAmlj

— NASA Universe (@NASAUniverse) January 16, 2025

While on their spacewalk, Hague and Williams will be performing some other jobs too, including removing and then replacing a station part called a rate gyro assembly. These help to keep the station in the right orientation as it orbits the Earth at 250 miles above the planet’s surface. They will also be doing other maintenance, like replacing a reflector device on one of the station’s docking adapters. These reflectors are used for navigation, helping to indicate the position of the docking area. Finally, they will also check over an area that will have maintenance work performed on it in future.

This future spacewalk will tackle maintenance on the Alpha Magnetic Spectrometer, an “unfixable” dark matter instrument from 2011 which astronauts succeeded in fixing in 2023. The instrument was designed to last only for three year and was not intended to be maintained by astronauts, but given its scientific value, NASA was able to fabricate new tools to open it up and upgrade its cooling system, allowing it to continue operating.

You can watch along with the spacewalk here: