Yonatan Zunger has a much better and still understandable explanation of just what SpaceX accomplished tonight and why it’s such a huge deal.
Originally shared by Yonatan Zunger
Huge kudos to SpaceX for the successful launch and landing of a Falcon 9 rocket today. This is the first time anyone has ever flown a rocket to orbit and landed it upright. That’s a big deal, because:
– Right now, rockets get dumped into the ocean or otherwise discarded after use, which is a big part of why flying to space is so expensive. It’s like building a 747 and using it once.
– While people have flown to orbit and landed again (in the Space Shuttle), that required the use of a winged lifting body, which is enormously more complicated and expensive than a simple rocket. Also, the Shuttle required a big external tank and two booster rockets – which got jettisoned.
– While people have launched rockets and landed them vertically before (Blue Origin, just a few months ago), those rockets weren’t capable of going into orbit. And going to orbit is a big difference from going into space: space isn’t very far away at all, you just need to go about 60 miles straight up. Orbit isn’t high, it’s fast: orbit basically means that you’re going fast enough that you keep falling towards the Earth and missing. Getting to that speed is a lot harder than just going up and falling down again.
– While people have tried to launch non-winged rockets into orbit and land them again (SpaceX, twice in the past year or so), it hasn’t worked, because you’re basically trying to land a pencil on its tip as it descends at a speed of a few thousand miles per hour. Previous attempts tried to land on boats (a pair of robot-controlled “autonomous spaceport drone ships” named the Just Read the Instructions and the Of Course I Still Love You), and the reason for the failures can be summarized as “now try to do that in high seas.” This time, they landed on solid ground, which isn’t as good from an orbital trajectories perspective, but which has the advantage of not moving about underneath you. (Usually)
This was a full-scale mission: a Falcon 9 took off from Cape Canaveral carrying eleven communications satellites. The first stage separated from the upper part of the rocket and landed safely, while the upper stages deployed the satellites into orbit.
So that’s a major success for one of the most exciting companies in space travel today, and something that’s likely to seriously cut the price of space travel over the next few years.
http://www.theverge.com/2015/12/21/10640306/spacex-elon-musk-rocket-landing-success
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