ANOTHER SpaceX Success: Booster Brought Back To Barge!
16/4/2016
Not so much passing a milestone as rounding a buoy!
Great video shows remarkably smooth and fast April 8th "landing" of
giant Falcon 9 booster rocket onto SpaceX's whimsically named
“Of Course I Still Love You” droneship.
giant Falcon 9 booster rocket onto SpaceX's whimsically named
“Of Course I Still Love You” droneship.
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This is only 9 minutes after successfully launching their Dragon capsule on the NASA-contracted CRS-8 (Commercial Resupply Services) mission to deliver 3 tons of supplies to the International Space Station.
The capsule has since (10/04) successfully docked and been attached to the International Space Station, and will remain there for about a month before returning to Earth with critical science and research payloads for NASA. Click for 2:40 highlight video of the docking. |
In my previous blog of 23/12/15, "SpaceX Success: Booster Brought Back To Base!" I have already mentioned the economic breakthrough of achieving a landing to re-use this booster; the Falcon 9 design costs $60 million to make and that's a lot to throw away every mission. Since it only costs $200,000 to fuel, and as long as refurbishing it for relaunch is much cheaper than building from scratch, this approach is set to dramatically reduce the cost of Earth-orbit launch missions.
Why are they trying to land on a little barge?
The barge landing has been achieved after four unsuccessful attempts. You may ask why SpaceX have persisted with trying to land on this tiny target when they have just launched from a perfectly good large spaceport.
The answer lies in trajectories and fuel usage. The rocket is not trying to launch the payload straight up, but into a circular orbit. This means its launch path tilts after launch into a long parabolic curve, travelling almost horizontally at separation of the payload. It would then take a lot of fuel to reverse direction and turn back for a landing near the launch site, leaving much less fuel to spare for landing manoeuvres.
Instead, it is much simpler to just carry on over and down to land where it would naturally fall anyway. This requires only to have the barge pre-positioned at that location, and some fuel to rotate the booster end-over-end, then decelerate and guide the tail-first landing, errr, barging?
The answer lies in trajectories and fuel usage. The rocket is not trying to launch the payload straight up, but into a circular orbit. This means its launch path tilts after launch into a long parabolic curve, travelling almost horizontally at separation of the payload. It would then take a lot of fuel to reverse direction and turn back for a landing near the launch site, leaving much less fuel to spare for landing manoeuvres.
Instead, it is much simpler to just carry on over and down to land where it would naturally fall anyway. This requires only to have the barge pre-positioned at that location, and some fuel to rotate the booster end-over-end, then decelerate and guide the tail-first landing, errr, barging?
p.s. The recovered Falcon 9 first stage (B1021) from this mission became the first one to be flown again, launching the SES-10 satellite on March 30, 2017.