The aircraft is said to be hypersonic. Typical low earth orbit re-entry speeds are near 17,500 mph and the Mach number M is nearly twenty five, M < 25.

During re-entry, the shuttle is going so fast, it compresses the air ahead of it. The compression of the air layers near the leading edges of the shuttle is quick, causing the temperature of the air to rise to as high as 3000 degrees Fahrenheit! Being in contact with the shuttle, it heats the shuttle’s surface.

Descent through atmosphere: After it’s safely out of orbit, the shuttle turns nose-first again and enters the atmosphere belly-down (like a belly-flop) to take advantage of drag with its blunt bottom. Computers pull the nose up to an angle of attack (angle of descent) of about 40 degrees.

Escape velocity is a term we use when we want to escape from the Earth’s gravity. So we don’t actually achieve escape velocity. That would actually be if were going at least 25,000 miles per hour. For our purpose, we go into a low Earth orbit we need about 17,500 miles per hour.

On the surface of the Earth, the escape velocity is about 11.2 km/s, which is approximately 33 times the speed of sound (Mach 33) and several times the muzzle velocity of a rifle bullet (up to 1.7 km/s). However, at 9,000 km altitude in “space”, it is slightly less than 7.1 km/s.

The human body is a very delicate thing and does not handle large accelerations well, and this includes spinning. If our jumper lost even a little bit of stability as he fell through the atmosphere, he could begin to tumble.

It is easy to penetrate the atmosphere quickly, and burn up like a meteor. The problem is to enter slowly. You can do that too, but it would take a huge amount of fuel with ordinary rockets. To skim the Earth’s atmosphere in orbit, your spacecraft has to travel at least as fast as 7.8 km / second, or about 17,500 mph.

When the meteor hits the atmosphere, the air in front of it compresses incredibly quickly. When a gas is compressed, its temperature rises. This causes the meteor to heat up so much that it glows. The air burns the meteor until there is nothing left.

Re-entry is a technologically challenging thing to survive, and even the smallest problem can escalate quickly, as the Columbia disaster taught us only too well. The main source of the problems with re-entry is that if you’re orbiting the earth, you’re going extremely fast.

For the closer satellites, engineers will use its last bit of fuel to slow it down. That way, it will fall out of orbit and burn up in the atmosphere. It can take a lot of fuel for a satellite to slow down enough to fall back into the atmosphere. That is especially true if a satellite is in a very high orbit.

A rocket, continuously accelerated by its exhaust, can escape without ever reaching escape speed, since it continues to add kinetic energy from its engines. Once escape velocity is achieved, no further impulse need be applied for it to continue in its escape.

How does it feel for the astronauts? Getting into space is a pretty demanding journey – and it takes a physical and mental toll on astronauts. “If you think about it, we’re accelerating a 4-1/2 million pound system from zero miles per hour to its orbital velocity of 17,500 miles per hour in those 8-1/2 minutes.

The Shuttle uses a rocket propulsion system to get into orbit, but during re-entry the aircraft is actually an un-powered glider. Small steering rockets are used for maneuvering early in the re-entry because the low density of the air at altitudes above 50 miles makes aerodynamic surfaces ineffective.

As a spacecraft re-enters the earth’s atmosphere, it is traveling very much faster than the speed of sound. The aircraft is said to be hypersonic . Typical low earth orbit re-entry speeds are near 17,500 mph and the Mach number M is nearly twenty five, M < 25 .

The figure shows the Shuttle after it has passed through the re-entry regime. The Shuttle uses a rocket propulsion system to get into orbit, but during re-entry the aircraft is actually an un-powered glider.

The ascent process begins with the liftoff from the launch pad. Propellant is being burned from the Solid Rocket Boosters, or SRB, and the external tank, or ET, causing the space shuttle to accelerate very quickly.