Photos: Tuesday’s Atlas 5 rollout

The enigmatic X-37B spaceplane, launched into low-Earth orbit on an experimental military mission in 2015, continues to circle the planet despite a flurry of landing rumors.

After unusual concentrations of hydrogen around the rocket foiled a launch attempt Dec. 19, United Launch Alliance said Friday that the company’s powerful Delta 4-Heavy launcher and a U.S. government spy satellite will remain grounded in California until at least Jan. 6 as engineers troubleshoot a small fuel leak.

The United Launch Alliance Atlas 5 rocket carrying NASA’s InSight lander toward Mars will have a roughly two-hour predawn launch window each day from May 5 through June 8 to boost the science probe into space from Vandenberg Air Force Base, California.