United Launch Alliance will salvage the main engines through a mid-air recovery plan and reuse them again aboard the company’s new Vulcan rocket, saving 90 percent in booster propulsion costs, the company announced Monday.

NASA declared the Spitzer Space Telescope’s 16-year mission complete Thursday after sending final commands for the spacecraft to enter hibernation as it drifts farther from Earth.

A robotic space shuttle with stubby wings, tail fins, its belly covered with black thermal tiles, clam-shell doors that swing open to reveal a payload bay and a solar array for ultralong-duration missions rode into orbit Wednesday on the fourth mission of the Air Force’s reusable X-37B spaceplane project.