Elon just posted this on twitter:
I am speechless!!!! I cannot believe my own eyes. Elon has said that the way to get rocket costs down is to allow them to return to earth from orbit. I guess this is how they are going to do it!!! Looks like they are very close.
What I find cool about this rocket landing is that in the 1960's they had a Rocket that showed up in Godzilla vs Monster Zero that could land much like this rocket could and fly though space and land on a planet and blast off and land again on earth. We should have had something like this 40 years ago.
Um, hate to disillusion you, but that Godzilla rocket was fake.
But the space X one is rocketing into reality. The question though is could the Godzilla movie rocket have given someone the idea of building a real version of it. In that they both operate under the same idea of blasting off and landing upright which is sort of freaky that they would be able to get the real life rocket version to behave like the plastic science fiction movie rocket.
Here's a very good and easy to understand page about orbital re-entry:
Also not that serious one.
I think that grasshopper needs to be slowed down first using parachutes or something cheap like that, because using rockets alone would require practically double fuel load to get to orbit and back.
Uses a nose heat shield for first part of descent, if its from near orbit or higher, and then flips to use rockets for final maneuvering and landing.
My reaction when I saw this video a few days ago was that now rockets can do circus acrobatics. Incredible what software allows you to do.
Great link spelling out what I could only suspect: that speed is where most of the energy goes, no height. I guess that shoots down my inflatable hydrogen balloon spaceship idea unless I can prove that drag will not be an issue and that high speed can be easily attained, which was always the tricky part.
@Ocean - Absolutely. Science Fiction is a very real driving force in what later becomes Science Fact.
We did have this 40 years ago. Neil Armstrong did the same thing on the moon (landed with rockets). Now we have computers that can achieve the same feat.
...but there is a lot less gravity on the moon and therefore much more difficult to accomplish on earth.
Gravity is just a variable in an algorithm. I would say it's a constant but gravity varies depending on where on the planet you're landing.
...but it also means you need a lot less thrust to support the lander than you would on Earth. Making it physically smaller, lighter and vastly simpler to manage.
Also shape of the vehicle affects this. Grasshopper is long, so even small deviation from the vertical line shifts balance a lot. There are also winds here, moon doesn't have atmosphere, so doing same there is not a big deal.
But NASA has been doing similar tricks on Mars (Skyhook with the Curiosity lander). I'm sure that NASA would have had the entry vehicle properly land instead of crash if the mission demanded it (but it didn't). Mars has an atmosphere (much less dense) and wind.
I'm not saying this isn't a significant achievement and way way cool. And yes, this is hard to do with a needle shaped vehicle on Earth. But like with most things, it's built upon the previous achievements of other missions. SpaceX did do this on their own, but they have a lot of former NASA engineers working for them.
Centre of gravity. Skyhook had weight under rocket engines. This one has it above.
Very cool. Go SpaceX. I wonder how long until we start seeing Falcon 9's with landing struts? Also, anyone know why they are switching to an octagon pattern for the 9 engines, instead of keeping the 3x3 layout? My first guess was to provide more space between the engines to help with thermal problems, but it's just an uneducated guess.
seems to be just general improvement over 3x3 layout.
Moves thrust closer to the center.