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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.
That's the plan. It may be possible for some launches to have all three come back to dry land if the payload is at the low end of capabilities.
One of the interesting things in this trip are a couple of Space adapters
There is only a single IDA in the CRS-9 dragon trunk this trip.
IDA-3 (to replace the lost IDA-1 from CRS-7) is targeted to launch on CRS-12 in May 2017.
The rocket launches due East from the Cape. The droneship is in a straight line underneath the flightpath, so the stage flies more or less a parabolic arc to the ship.
To fly back to the Cape, the stage has to brake and bring its velocity to 0, then accelerate to the West to get back to land.
Flying to the drone ship skips the 'brake' part, which saves a lot of fuel.
Well, in theory it *could* if it had the fuel, and I bet that for a really light GTO payload they could manage to save enough fuel for the boostback burn, but in practice satellites intended for GSO aren't that light. It would be a longer boostback burn (than for LEO) anyhow, because the first stage is usually going faster at separation when it's targeting GTO, but for a really light payload the second stage wouldn't need to burn for as long either so maybe the first stage could separate a little earlier.
No matter what the target orbit, the first stage will always be well down-range, and have a lot of velocity in that down-range direction, at separation. For ground landings, it needs to reverse that velocity to come back to the launch site, then do another burn to slow down enough to not burn up in the atmosphere, and then the landing burn. For GTO launches, it usually skips the first burn (boostback) and just continues along that down-range trajectory, doing just the re-entry and then landing burns. This obviously needs less fuel, but also means that the rocket is hundreds of miles downrange by the time it lands.
It's not theoretically impossible to do a full boostback burn after a GTO launch, though... just impractical given how much fuel the first stage uses on the ascent of a GTO launch.
There's no place I could be, since I've found Serenity...
Here is the launch profile. http://i.imgur.com/D9BdO86.png
Launches to GTO need to be going a lot faster (7.7 km/s for ISS, vs 9.88 km/s for GTO). The Falcon 9 uses up enough fuel that it cannot execute the "boostback" burn listed in the image.
Instead it continues on in a parabolic arc until it hits the atmosphere to slow down, firing the rocket at the last minute to stop over the drone ship.
https://upload.wikimedia.org/w...
I'm a good cook. I'm a fantastic eater. - Steven Brust
SpaceX started streaming a live "technical webcast" feed for the last several launches; here's the one for last night's launch: https://www.youtube.com/watch?...
In the past I think it's been linked from the webcast page, but you can also find it by searching Youtube.