Slashdot Mirror
SpaceX Dragon Launches Successfully, But No Rocket Recovery
New submitter monkeyzoo writes: SpaceX has successfully launched a Falcon 9 rocket carrying a SpaceX Dragon spacecraft en route to the International Space Station with supplies (including an Italian espresso machine). This was also the second attempt to land the launch rocket on a barge, but that was not successful. Elon Musk tweeted that the rocket landed on the recovery ship but too hard to be reused. Video of the launch is available on the SpaceX webcast page.
Musk tweeted here that the rocket landed fine but there was residual lateral velocity that tipped it over after landing. The photos on that tweet are worth looking at.
Obviously, now they have to work on fine positioning with elimination of lateral velocity before it comes down on the barge. Not an easy problem, especially given that the first stage doesn't have much Delta-V in its cold gas reaction control thrusters and does most of its positioning with the grid fins and the engine. Which means using more fuel. Hopefully there's enough, or room for building up the RCS.
Bruce Perens.
If it didn't survive, it can't be reused. Thus, both are accurate here. The reverse is not necessarily true.
Also, "Looks like Falcon landed fine, but excess lateral velocity caused it to tip over post landing". At least from the two pictures I've seen, it looks like it was coming in better than last time. Now we'll have to wait two months for a re-match.
The first one hit hard and sank into the water.
The second one touch down fell over and sank into the water.
I predict the third one will burn down, tip over, then sink into the water.
But the fourth one, that will stand!
Microsoft, Apple, Google, Amazon what's the difference? All steal money from devs and control with walled gardens.
That's why the call it rocket science.
They'll get there eventually. I am watching every try with a great deal of emotion.
Bruce Perens.
This is an achievement. Take it from an old rocket grognard, a veteran of Amroc, Orbital, and others: just getting this far is an accomplishment.
And it's smart of Musk to append a test operation onto a paying mission. The launch fee for the ISS delivery offsets a major portion of the cost of the test.
And in a test sequence, close does count, because all data gathered is useful. And often, data from a failure is more useful than data from a success.
"Success is a lousy teacher; it seduces smart people into thinking they can't lose." —Bill Gates
I can see the fnords!
Anyone who's played Kerbal has experienced that one aplenty ;)
Not sure what the best solution is. For example, maybe they can just improve the control and stabilization software for the system as it is. I'm sure they're really hoping that's possible! It's probably the most likely and cheapest approach.
I'd be really "easy" to land if they had an RCS, just a couple seconds worth to cancel out any lateral movements and rotations - but that'd still be a lot of mass. Maybe if they had an RCS they could narrow / weaken / lighten the landing gear to pay for the added mass?
Or maybe the solution has nothing to do with the rocket. Maybe they need something to grab it on the way down? I mean, planes landing on carriers grab a hook, maybe there's a rocket equivalent for this? One envisions comic-book-ish solutions like landing in a giant net, but there may be practical answers.
Or maybe combine the two. Maybe there's no RCS on the rocket, and no grabbing system on the barge, but rather a supersized reverse RCS system on the barge, big jets that can be fired up and shut off in an instant, aimed at blowing the rocket to induce a leveling force on it.
Or maybe you don't need to apply a leveling force further up on the rocket - maybe you just need to provide some torque where it's touching the pad. Maybe the pad could be mounted on powerful hydraulic pistons to jerk to keep the rocket stable even if it's got some lateral or rotational inertia when it touches down.
I really don't know. But I really hope they get it. And I really hope it's the first option, because things start getting technologically uglier if you have to complicate the landing.
*Kid Rock runs for Senate* Democrats: We must run Kid Scissors.
1. That is why I mentioned Vandenberg, which is on the West coast and launches to the South for Polar Orbits
2. Space-x has mentioned moving their landings to terra-firma
I appreciate your reply, hopefully somebody who know more than either of us will offer up some tidbits of info
Wherever You Go, There You Are
SpaceX happens to have another barge for the Vandenberg launches. It still is a big deal in terms of landing in a desert, as you have the option of either trying to fly laterally to Mexico (with some international arms control problems with ITAR) or overfly Los Angeles and/or San Diego with that rocket.
Vandenberg happens to be located at a point where California sort of turns off to the east, and is used for polar orbits explicitly because there is a whole lot of nothing except for ocean between Santa Barbara County and Antarctica. Try to look at a map sometime and answer this question: Which city is further west: Los Angeles or Reno?
There is a landing pad being constructed both at KSC (in Florida) as well as at Vandenberg. Right now both NASA and more significantly the USAF (for Vandenberg especially) are waiting to see the results of landing on the barge first before formal approval for landing at the pads is going to be authorized.
It should be pointed out too that SpaceX does have a landing pad with several dozen square miles of desert to work in at Spaceport America in New Mexico. There was some construction work going on there at least in the recent past, and so far as I know the tests to be conducted there haven't been canceled although most of the current effort seems to be work on the revenue flights like this CRS-6 flight rather than the proposed test flights in New Mexico that were to be suborbital flights mainly going up really high and then coming back to the Earth with possibly a flight over White Sands (which is adjacent to Spaceport America and is both restricted airspace and ground access due to it being a military base). Flight clearance at that location is such that they can go much higher there than they can at their Texas test facility.
As long the launches are at KSC or Vandenberg, however, the recovery at the moment will simply need to be at sea. Physics also plays a part as other than returning to the original launch site, down range from either launch site is simply ocean as far as you can go in the general flight path.
I'd be really "easy" to land if they had an RCS, just a couple seconds worth to cancel out any lateral movements and rotations
In its current configuration, the stage can't hover: on its lowest thrust setting, the engine still provides too much thrust. So they land using a "hoverslam" maneuver where they try to decelerate to a vertical speed of 0 just as the stage intersects the barge.
There is an RCS at the top of the stage to keep the stage upright, but any lateral thrust at the bottom has to be done by gimbaling the main engine. The gimbaling angle is limited so they may have run out of control authority on this landing.