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SpaceX Successfully Lands Falcon 9 Rocket On Solid Ground For the Second Time (theverge.com)
SpaceX successfully landed another Falcon 9 rocket after launching the vehicle into space on Sunday evening from Florida. The Verge reports: Shortly after takeoff, the vehicle touched down at SpaceX's Landing Complex 1 -- a ground-based landing site that the company leases at the Cape. It marks the second time SpaceX has pulled off this type of ground landing, and the fifth time SpaceX has recovered one of its rockets post-launch. The feat was accomplished a few minutes before the rocket's second stage successfully put the company's Dragon spacecraft into orbit, where it will rendezvous with the International Space Station later this week. It's also the first time this year SpaceX has attempted to land one of its rockets on land. For the past six launches, each rocket has tried landing on an autonomous drone ship floating in the ocean. That's because drone ship landings require a lot less fuel to execute than ground landings.
What that said the launch was by the numbers and was awesome. I've got friends in FL who heard the sonic boom of the first stage reentering.
Since they were only boosting Dragon to LEO they didn't have to deploy the drone ship. I watched it online last night. I did notice the feed started with only a few minutes before launch which saddened me because I like to listen in on the launch coordinator loop while they're going through all the preflight checks.
Hopefully SpaceX will expose the audio feed so those of us who are nerds about this can listen in for the whole thing.
Yes Francis, the world has gone crazy.
"I've got friends in FL who heard the sonic boom of the first stage reentering."
I watched some Periscope recordings from people watching the landing, and they all seemed to be shocked by the loudness of the sonic boom. Some thought the 1st stage booster exploded after landing (because it takes a while for the sound to reach them).
SpaceX claims "this is no worse than the sonic boom from the shuttle landing", but I don't know, I've heard the sonic boom from the shuttle landing at Edwards and it was like someone hitting a drum, not like an explosion.
NASA was lucky to land one shuttle per month, whereas SpaceX has dreams of launching/landing once per week.
Also the people near the Space Coast or Vandenberg might be able to deal with the sonic booms (as space is pretty much their whole industry), but if SpaceX moves launches/landings to Brownsville, Texas, I can imagine they will upset a lot of people in Harlingen, McAllen, and Corpus Christi not used to rocket launches or supersonic aircraft (not to mention our friends across the border in Reynosa).
For 2016 they are hoping to do 16 launches and that's considered overly optimistic, SpaceX has been doing around 10 launches per year. To get to 1 launch per week (52 per year) is a huge step forward and will not come for years. Even if they do get to 1 launch per week, with 3 launch sites that's still 17 launches per site per year. Of those only LEO missions can return to the launch location, launches to GEO have to land downrage on a drone ship. All in all, the good people of Texas have nothing to worry about.
Although, on the other side of the equation it's not as bad as it could be for several reasons:
1) The first stage does most of the "up", the second stage is almost entirely about the "across" portion. The first stage also does part of the "across", but its main purpose is to get the second stage out of the atmosphere to where it can operate efficiently.
2) The second stage comes back vastly ligher than it left.
3) Aero drag helps get rid of part of the forward velocity.
That said, it's still very difficult to get back, because getting to orbit is so demanding to begin with. You can't just reserve a quarter of your fuel for the return and still plan to get a useful payload to orbit. You have to return running on the dregs of the tanks.
Hourglass says she knows a kid in Iowa who grows up to be president.
Yep. The video doesn't make it clear, because the cameras are all either tracking the rocket or are mounted *on* the rocket, but the first stage is going really fast at separation, and a lot of that velocity is lateral. Going to *space* only requires going up a relatively short distance, but going to *orbit* requires going extremely fast around the planet. After the first few seconds post-liftoff, the rocket is angled mostly downrange, not just up. To come back to the launch site, the rocket not only needs to kill all that down-range velocity, it needs to boost *back* to the launch site.
The rocket does actually need to do a braking burn when landing on a downrange barge anyhow, but the purpose is different. Rather than being focused on reversing the rocket's forward trajectory, it's focused on slowing the rocket down so it can re-enter the atmosphere safely. By the time of separation, the stages are quite high - well out of the thick part of the atmosphere - and sheer momentum will take them quite a bit higher. Eventually gravity takes over, though, and between gravity pulling the rocket downward and that downrange momentum still making it go forward so fast, the rocket wouldn't survive re-entry if it didn't use its motors to slow down. This re-entry braking burn is done both for land and sea landings.
There's no place I could be, since I've found Serenity...