An X-ray observatory used to study neutron stars is “back in the black” and ... upgrades after two astronauts completed a spacewalk outside the International Space Station (ISS).

An annual memorial was held at the Kennedy Space Center Visitor Complex. Every fourth Thursday in January, NASA remembers fallen astronauts.

NASA astronaut ... “back in the black” and a cosmic ray detector is ready for possible future upgrades after two astronauts completed a spacewalk outside the International Space Station ...