Q&A with Keith Gendreau, principal investigator of the first X-ray space communications experiment (members only)

A troublesome liquid oxygen valve on the Space Launch System’s first flight-rated core stage will keep NASA from performing a second test-firing of the rocket’s four main engines this week.

The mission is a follow-on from NASA’s planetary defense mission, DART, which succeeded in changing the orbit of an asteroid around its larger neighbor. Liftoff happened at 10:52 a.m. EDT (1452 UTC).

The precautions were announced the same day as NASA said Roscosmos cosmonauts are set to perform “a more extensive repair operation”, but without providing details as to what that entails.