Dropping Science: Space Ship 2 Feathers to Earth Safely
Many of you will already be aware of Virgin Galactic and their quest to bring commercial space flight into the realms of reality. Well that quest too a big step forwards this month as their prototype craft – imaginatively named “Space Ship 2” performed its first successful “feathered” re-entry to earth.
The basic principle of feathering is this: When a space craft re-enters Earth’s atmosphere it picks up a whole craptonne of speed and resulting friction from the air around the craft causes it to heat up. This is why objects burn up when they enter the atmosphere, it’s not that the atmosphere itself is hot, they’re simply burning up under their own velocity. Conventional space craft such as the Space Shuttle get around this issue by employing thick layers of heat resistant plating which is designed to protect the ship until it reaches a safer speed. This is not only a rather expensive and inefficient solution but, as we’ve seen from the Columbia disaster of 2003, an extremely risky one. In the case of Columbia a piece of foam broke of during launch and knocked a hole in the heat shield of one of the wings, even though the damage was tiny it was enough to compromise the shield to the point that the shuttle disintegrated upon re-entry.
With Space Ship 2, Virgin Galactic have decided to do away with heat shielding entirely. Instead the entire space craft “feathers” upon re-entry, literally bending in the middle. This has the effect of rapidly and safely decelerating the craft before friction has a chance to build up. No friction, no heat, safe landing. It’s an incredibly elegant solution to a problem that has persisted ever since the start of the space race and as of this month we know that it works!
Mankind is one step closer to the stars and if that’s not exciting then I don’t know what is.