Slashdot Mirror
SpaceX Launches Load to ISS, Successfully Tests Falcon 9 Over Water
mosb1000 (710161) writes "SpaceX is reporting that they've successfully landed the first stage of their CRS3 Falcon 9 rocket over the Atlantic Ocean today. This is potentially a huge milestone for low-cost space flight." In another win for the company, as the L.A. Times reports, SpaceX also has launched a re-supply mission to the ISS.
Interesting that a russian naval ship (called a tug, but how many miles off florida coast ? ) was there at the landing site to watch this.
I think that everybody who continues to knock SpaceX, is realizing that they are all in serious trouble.
I prefer the "u" in honour as it seems to be missing these days.
Data upload from tracking plane shows first stage landing in Atlantic was good! Flight computers continued transmitting for 8 seconds after reaching the water. Stopped when booster went horizontal. Several boats enroute through heavy seas...
The issue is NOT whether they they recovered the stage, but whether it landed at slow controlled speeds. Apparently, SpaceX feels that it did 'land' on the water. As such, one or 2 more times with this, and they will be able to put it on land.
Personally, I think that bringing it all the way back to the cape is a mistake. Instead, they should use one of the old oil rigs that are out there. Clean it up, land it on the rig, and then offload with a crane to a barge and take it back for launc.
I prefer the "u" in honour as it seems to be missing these days.
They soft landed, that's a success whether they are recovered or not. You didn't expect them to stand upright in the water like a buoy did you?
I remember reading that of the $20 million cost of a launch only about $500,000 was due to fuel, so this is a complete game changer.
Right idea, but wrong numbers. A Falcon 9 launch, not including the cost of the payload itself, is nearly $60M, while the fuel for it is only a quarter million.
The rocket (1st stage) when empty needs almost no fuel (about 4% of the total fuel at launch) to return to the launch site and land. The upgraded Falcon v1.1 has 10% more fuel at launch as well as increased cargo capacity (more efficient engines). Hitting a floating barge means you have to have good conditions at the launch site, as well as 400 miles out at sea as well. That dramatically limits your launch capability and exponentially increases your recovery costs.
moox. for a new generation.
I'm curious to know if this first stage had landing gear attached (maybe not because of the additional weight, drag). Also, in the future when they DO try to land it on land, where will they be aiming? If the flight profile of the first stage is mostly vertical then, without much fuel I guess they could return to Florida, otherwise would they be going for a Caribbean island? The Azores or Canary Islands? Africa? I'm sure they've got this figured out, I'm just curious.
This test did have the landing gear attached and deployed during landing, as the aerodynamics of it are potentially problematic (one of their tests failed when it entered a spin before landing).
The first stage flight path doesn't seem to be mostly vertical - I'm having a hard time finding solid info, but based on images of the first-stage separation, I'd estimate it to be no more than a quarter of the way across the Atlantic. I do know that their plan is to return the rocket to the launchpad for landing, which wouldn't make much sense if it was much further away by stage 1 separation.
Their flight path does seem a bit weird, though - of the Space Shuttle abort modes, Return to Launch Site was the riskiest and most difficult, compared to Transoceanic Abort Landing (landing in a European or African site) or Abort to Once Around (doing a full orbit then landing as normal). Either the Falcon is accelerating far faster once they break the atmosphere, or the Space Shuttle accelerated horizontally a lot earlier than it may have needed to.
The purpose of recovering it is to cut costs. Even if the stage becomes reusable, how much it is actually going to save is still an open question. In such case, landing it offshore, and transporting is not going to help with the costs.
SpaceX is audacious, but I am sure they will take all precautions and won't attempt to land it in the pad, unless they are highly confident that it will work.
RTLS, TAL and AOA all relied on the main engines. If all three SSMEs failed they would have ditched it in the Atlantic. The scenarios aren't really comparable - they had a lot more fuel to work with but also a much heavier vehicle to return.
RTLS is easier for the Falon 9. After separation the stage 1 assembly is quite light: it has shed the payload, second stage, and most importantly, most of its own fuel; the remainder is about 5% of the original mass. It can therefore make a pretty quick burn to reverse its course.
They have some real numbers over here: http://forum.nasaspaceflight.c... .
Well, this is the commemorative weekend for an ancient Israeli dude who reportedly could walk on water, died and turned into a zombie. So, if that was possible, who knows, maybe Space-X can stand their rocket on water.
Excuse me, but please get off my Pennisetum Clandestinum, eh!
" You didn't expect them to stand upright in the water like a buoy did you?" Actually I would, when the booster from the shuttle land on water (here is a video https://www.youtube.com/watch?...) at first it goes horizontal but a few seconds later they go back straight up, because it is basically an empty cannister with some quite heavy engines on the bottom. IIRC before they start tugging the booster divers have to attach some hoses to pump water into the booster and make them go horizontal.
It got up there while carrying a lot more propellant and a whole second stage. The braking burn uses only 3 engines to limit the acceleration and ends with just enough propellant left to stop it when it reaches the ground. On top of this, it gets passive aerodynamic braking the whole way down.
The mass ratio for the first stage burn, burdened with the second stage and braking propellant, is probably around 4, and a braking burn with equal delta-v would need the same mass ratio, except with no second stage and ending with the rocket empty. The overall first stage mass ratio is around 30, so all else being equal, a return would take around 3/29 = 10% of the propellant on the first stage. But all else is not equal, the returning rocket is mostly empty tanks descending through a thick atmosphere that provides plenty of braking, so the final burn only has to bring it to a halt from terminal velocity, and I omitted the second stage propellant. Overall, 4% sounds quite reasonable.