Epo: We are now in orbit around the planet.
Granddaughter: Wow, look at that view.
Computer: Our hull temperature is increasing! Our orbit is degrading!
Epo: Impossible! my altimeter does not show any anomaly.
Alkina: Epo, monitor the hull temperature! Is it increasing?
Epo: Curious. It is but it shouldn’t be.
Computer: The hull temperature is approaching critical levels.
What does it mean?
Altitude – the height of an object above a reference plane, usually the surface of a planet. On Earth, the sea level is used as the reference plane.
Altimeter – an instrument to measure altitude.
In human speak please!
As a spaceship enters a planet’s atmosphere it experiences friction, or resistance, due to collisions with the gaseous molecules that make up the atmosphere. This friction causes the outside surface, or hull, of the spaceship to start heating up. You can experience heat generation due to friction by quickly rubbing your hands together.
As we have discussed in past episodes, spaceships travel at very high speeds. This, and the fact that a spaceship goes from an environment (space) that has no atmosphere to one that does is the reason why there is so much heat generated. If the spaceship is not protected adequately (by using a design and materials to reduce heat generation) and the angle of the reentry is not correct, the friction could damage or destroy the ship.
Is that all?
Kennedy Space Center – The main website for NASA’s space shuttle program.
Why doesn’t the space shuttle burn up when it hits Earth’s atmosphere? – Click on the link to find out the answer.