How to Land the Space Shuttle... from Space

Summary

In this engaging and humorous talk, the speaker explains how to land a space shuttle, using the example of a mission returning from orbit. They describe the technical challenges of slowing down from speeds of over 17,000 mph, the shuttle's unique aerodynamic properties, and the methods used to control descent using bank angles and re-entry maneuvers. The speaker covers key phases like de-orbit burns, atmospheric entry, and landing approaches, all while offering insights into the science and engineering behind this complex process in an accessible, entertaining way.

Takeaways

• 😀 The Space Shuttle lands on a runway at Kennedy Space Center, despite starting over 17,000 miles away in orbit.
• 😀 The shuttle's speed at reentry is 17,000 miles per hour, and it would cover the entire 15,000-foot runway in just 0.6 seconds without slowing down.
• 😀 The shuttle uses minimal fuel after launch, with its main engines burned out, relying on small orbital maneuvering engines for the deorbit burn.
• 😀 A deorbit burn of 225 miles per hour is enough to begin descending into Earth's atmosphere, using air resistance to slow down further.
• 😀 The shuttle must pitch to a 40-degree angle of attack to prevent overheating and to protect its aluminum frame using silica tiles and carbon-carbon panels.
• 😀 Upon entering the atmosphere, the shuttle generates lift with its wings, which causes it to rise temporarily, requiring precise control to prevent skipping off the atmosphere.
• 😀 Roll control (changing bank angles) is used to adjust descent speed, allowing the shuttle to manage its descent rate without overheating or losing control.
• 😀 Managing descent speed involves balancing air density, where banking more aggressively brings the shuttle into denser air more quickly, aiding in deceleration.
• 😀 NASA's solution to controlling descent when the shuttle veers off course is a series of S-turns, known as roll reversals.
• 😀 As the shuttle descends through the atmosphere, the commander manually takes over at lower altitudes for the final stages of landing, transitioning from autopilot to manual control.
• 😀 The final landing is executed by reducing the shuttle's descent rate with a preflare maneuver, deploying landing gear, and touching down at about 225 miles per hour.

Q & A

Why can't the space shuttle simply turn around to head towards Kennedy Space Center?

Changing direction in orbit takes enormous amounts of energy, making it impractical to just turn around. Instead, the shuttle uses the Earth's rotation to naturally bring Kennedy Space Center into its path.

How fast is the space shuttle traveling when it approaches the landing site?

The shuttle is traveling at over 17,000 miles per hour when it starts its approach to the landing site, which is much faster than typical aircraft.

Why can't the space shuttle rely on its engines to slow down during re-entry?

The shuttle runs out of fuel after launch, so it cannot rely on its main engines. The only remaining engines are small orbital maneuvering engines, which produce less than 1% of the thrust needed to slow down the shuttle sufficiently.

What is the purpose of the de-orbit burn in the shuttle's landing process?

The de-orbit burn is a critical maneuver where the shuttle's small orbital maneuvering engines are fired to reduce its speed by just 225 miles per hour. This is enough to start the shuttle's descent into the atmosphere.

Why does the space shuttle need to maintain a 40-degree angle during re-entry?

The 40-degree angle of attack ensures that the shuttle's heat shield can protect it from the intense heat during re-entry. The shuttle's aluminum airframe is protected by over 20,000 silica tiles and reinforced carbon-carbon panels.

How do the shuttle’s wings affect its descent during re-entry?

The shuttle's wings generate lift, and as it enters denser air, the lift increases. This causes the shuttle to climb back up, which could result in it skipping off the atmosphere. The shuttle uses bank angles to control this and regulate its descent speed.

What role do the shuttle's bank angles play in its descent?

The bank angles control how much lift the shuttle generates. A steeper bank increases descent speed by reducing lift, while a shallower bank reduces descent speed by maintaining more lift.

What are role reversals in the shuttle's re-entry process?

Role reversals are when the shuttle adjusts its bank angle in the opposite direction during descent. These maneuvers help control the descent rate and ensure the shuttle doesn't overshoot or miss its landing site.

What is the purpose of the Terminal Area Energy Management (TAEM) mode?

TAEM is a guidance mode used when the shuttle is near the runway. It helps manage the shuttle’s descent rate and path, using both pitch and bank to align with the runway centerline and ensure a safe landing.

What is the significance of the shuttle’s descent rate during landing?

The shuttle’s descent rate is significantly higher than a commercial airliner’s. It descends at about 10,000 feet per minute, which is much faster than a typical airliner. This steep descent requires careful control to avoid crashing or overshooting the runway.