Stats: Delta 4 history and manifest

Trouble with one of the Hubble Space Telescope’s three remaining gyroscopes, critical for aiming and locking onto targets, prompted mission managers to switch to a backup control mode that will limit some observations but keep the iconic observatory running well into the 2030s, officials said Tuesday.

Two astronauts floated outside the International Space Station early Friday for the first of four planned spacewalks to wrap up a complex multi-year job to replace 48 aging batteries in the lab’s solar power system with 24 more powerful lithium-ion units.

NASA has selected a SpaceX Falcon 9 rocket — flying with a reused first stage booster — to launch the Imaging X-ray Polarimetry Explorer mission from pad 39A at the Kennedy Space Center in Florida in April 2021, bypassing Northrop Grumman’s air-launched Pegasus rocket for the task.