On A Glide

Short answer: The Space Shuttle orbiter came home without engine power. NASA's Glenn Research Center explains that once the external tank was gone, the main engines had no propellant, so the shuttle returned as an unpowered glider.

It had a low lift-to-drag ratio because it had to slow from about 17,300 mph to about 250 mph. About an hour before landing, a deorbit burn dropped it out of orbit. It entered the atmosphere nose-first at a 40° angle of attack to limit heating, and computers controlled its speed with a series of banking roll reversals. NASA's Kennedy Space Center fact sheet says commanders took manual control for the final approach during subsonic flight, usually about 22 miles (35 km) from touchdown. The initial approach glide slope was 20 degrees, more than six times steeper than an airliner's 3 degrees. Because the orbiter was unpowered, it had no go-around capability. It touched down at 213 to 226 mph. From 1991, orbiters were fitted with a 40-foot drag parachute, deployed as the nose came down, plus carbon brakes. Of 133 successful landings, 78 were at Kennedy's 15,000-foot Shuttle Landing Facility, 54 at Edwards Air Force Base in California and one, STS-3, at White Sands in New Mexico. The program flew 135 missions between April 12, 1981, and July 21, 2011, when Atlantis made the final landing. The footage shows an orbiter gliding over Florida wetlands, touching down and rolling out with its drag chute.