The Space Shuttle was both a spacecraft and an aircraft, which made its return to Earth one of the most demanding flights in aviation history. After leaving orbit, the orbiter entered the atmosphere at hypersonic speed and had no engines for powered flight. From that point on, it became a heavy glider that had to manage energy, heat, lift, and drag with extreme precision.
Its subtitle, The Flying Spacecraft, captures this unusual role: it flew in space, then flew home through the air.
Key Facts
- During landing, the Space Shuttle orbiter was unpowered and flew as a glider.
- Lift equation: L = 1/2 rho v^2 A CL, where rho is air density, v is speed, A is wing area, and CL is lift coefficient.
- Drag equation: D = 1/2 rho v^2 A CD, where CD is drag coefficient.
- The orbiter used a delta wing, which helped with stability and control at high speeds and high angles of attack.
- Typical landing speed was about 214 to 226 mph, much faster than many commercial airliners at touchdown.
- The final approach was very steep, about 18 to 20 degrees at first, compared with about 3 degrees for a typical airliner.
Vocabulary
- Orbiter
- The winged Space Shuttle vehicle that carried astronauts to space and returned to Earth as a glider.
- Hypersonic
- A speed regime faster than Mach 5, or more than five times the speed of sound.
- Delta wing
- A triangular wing shape that can handle high speed flight and provide useful lift and control during reentry.
- Angle of attack
- The angle between the direction of airflow and the reference line of a wing or vehicle.
- Glide ratio
- The distance an aircraft travels forward divided by the altitude it loses during unpowered flight.
Common Mistakes to Avoid
- Thinking the Shuttle used jet engines to land is wrong because the orbiter had no air-breathing engines and made its approach entirely unpowered.
- Treating the Shuttle like a normal airplane is wrong because it had a much steeper descent, higher landing speed, and lower glide performance than typical aircraft.
- Assuming reentry was just falling straight down is wrong because the orbiter used lift, banking turns, and drag to control its path and reduce speed.
- Ignoring air density in lift and drag calculations is wrong because both lift and drag depend on rho, so the forces change greatly as the orbiter descends into thicker air.
Practice Questions
- 1 A Shuttle-like glider has a glide ratio of 4.5:1. If it loses 8 km of altitude, how far forward can it travel in still air?
- 2 During final approach, suppose the orbiter descends at an 18 degree angle. If it travels 12 km horizontally, about how much altitude does it lose? Use altitude loss = horizontal distance times tan(18 degrees).
- 3 Explain why the Space Shuttle needed a steep approach and careful energy management during landing, even though it had wings like an airplane.