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Longer Video Shows How Incredibly Close Falcon Stage Came To Successful Landing
Bruce Perens writes In the video here, the Falcon 9 first stage is shown landing with a tilt, and then a thruster keeps the rocket vertical on the barge for a few seconds before it quits, followed by Kabooom with obvious significant damage to the barge. It looks like this attempt was incredibly close to success. Given fixes, a successful first-stage recovery seems likely.
It sure seems that if a larger landing area was available, so that the rocket didn't have to lean so far to adjust to a very small target and thus could prioritize staying vertical, it would be able to land successfully. What's it going to take for NASA or the FAA or whatever to give them permission to land on, um, land.
Better known as 318230.
Probably not when they figure out how to land on the barge without exploding... at that point the damage from hitting the water and amount of cleaning & service required to be read for launch will be much more.
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The falcon can't throttle down enough to hover before landing so it has to approach the pad at high speed, and high acceleration. While doing this it has to rotate the entire vehicle to control lateral movement. It has to coordinate lateral and vertical acceleration to achieve near zero in all three axes at touchdown, with only one chance to get it right.
I doubt this can be done without extra thrusters for fine control over velocity and position.
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You can see a lot more if you go to 1080 HD and full screen. There's some large piece of equipment, perhaps the motor head for one of the barge's corner thrusters, being thrust off of the barge in flames.
It looks like they'll need to do a lot of work on the barge. The support ship Go Quest and the tug Elsbeth III seem to be back in Jacksonville according to vessel tracking sites. There is a Carnival cruise ship that parks next to the barge's dock every 4 days, so we will probably see photos from its bow netcam if we don't see them otherwise.
Oh, check out this newscast. At 2:43, CBS News uses a sequence a SpaceX fan produced with Kerbal Space Program to illustrate how the landing is supposed to work.
Bruce Perens.
They have talked about refueling on the barge and flying the booster to land! That's really difficult to do after a salt-water dip :-)
Bruce Perens.
They have a job for you in the ULA marketing department.
Bruce Perens.
Why am I not convinced your way sounds like the "easy way"?
I can't event think of the mechanical stresses involved in opening this thing up to spin it around.
In fact, it sounds outright crazy.
And that's before we start considering a fuel tank designed to open up. Because, what could possibly go wrong there?
Lost at C:>. Found at C.
I've heard this point before, with the obvious comparison of Shuttle wings. The counter is that wings are absolutely dead weight on liftoff, plus you've added an entirely new structural mode to the airframe. It has to have the correct structural strength for both vertical ascent and horizontal landing. Both wings and bimodal structure add weight.
Landing the F9 on it's tail, it's practically empty, a fraction of it's initial weight. I'd be interested in seeing the math between F9 and Shuttle, but I suspect SpaceX has done their homework on this.
Of course the science fiction idea of landing anything that can then take off is just that - science fiction. The LEM did it, but then again, only half of the LEM - the bottom was left behind.
The living have better things to do than to continue hating the dead.
Looking at the video, it appears the booster does not come close to ever having anywhere near a true vertical orientation, and this attempt was not, in fact, "incredibly close to success". Granted, it came closer than ever in history to achieving the goal, but the thruster appeared to not have enough thrust to push the rocket to a vertical position once the booster touched down on the barge. I hope Space-X has a successful next test! The world needs a dose of rockets landing on large flames in the style of those old campy movies.
Every time there's a thread about this, someone says the same stupid thing you're saying, and it's still wrong.
There's a huge difference in power requirement in getting a fully fuelled and loaded rocket up in the sky, and slowing the descent of a nearly-empty, lightweight fuel tank. You need very little fuel to accomplish the latter. Don't forget that parachutes have mass too and it's very hard to make a controlled descent with them (especially if you need to carry the rocket a significant distance). All in all, the solution that best combines cost-efficiency with the ability to land precisely is the vertical retro-rocket landing that SpaceX adopted.
A fool and his hard drive are soon parted.
With Horseshoes and Hand Grenades. We've seen what "close" gets us with rocketry, and it's not pretty.
Kindergarten Question for SpaceX: why not simply put the equivalent of a safety net on the barge, cut the rocket's engines at an altitude of ~10m and let the rocket fall safely into the net? Less fuel, less complexity and less cost.
A couple of months ago I was having a discussion with a fellow from Space X who designs the hydraulic systems and we spoke about a number of issues. This was right after the failed landing due to it running out of hydraulic fluid. I asked about how reusable the engines are and he said that they run test burns lasting hours. The launch is only a few minutes. According to what he said, it should just be a simple matter of refueling and adding more hydraulic fluid and probably some other simple things without having to do a major overhaul. The engines are very reliable.
I asked about why they don't reuse the hydraulic fluid and he said that it was cheaper and lighter to not reuse it. He also said that they knew it could run out and that the next version would have more.
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A bit of rotation should help to keep the thing upright. The gases being pushed into the silo will be forced towards the walls on their way back out and help center the rocket as it enters the silo. A funnel-shaped silo is easy to hit and provides a soft cushion as the pressure of the backscattered gas increases as the rocket descends into it. Finally, a rotating platform at the bottom needs to be synchronized to the rocket's own rotation. Good Thing I don't have the billions it would take to see my brilliant ideas crash and burn.
- Musk has commented that the issue has been diagnosed as some stiction that was causing a lag between computer commands getting carried out. They believe the issue will be straightforward to fix. - Musk's claim is that the barge didn't sustain any serious damage.
"Droneship is fine. No hull breach and repairs are minor. Impact overpressure is closer to a fast fire than an explosion."â"Elon Musk
Build a large funnel, or infundibulum, on the barge.
All you have to do is hit the wide top of the funnel at a non-clusterfuck angle.
Then you let the structure of the funnel contain and guide the rocket as it continues on down.
If you fuck up badly, you won't lose everything. And if you do very well for 98% of the landing but tip toward the end, damage from impacting the walls of the vertically will be incidental and minor as the rocket is still thrusting to lower its velocity (and thus the force of the impact).
And if you do it successfully the funnel isn't touched.
Alternatively, do the same but instead of a solid funnel, use closing arms so you can actively catch and assist the rocket if need be, or drop the arms and let the rocket fall into the ocean if you have to abort.
You could also put 8 electromagnets in a circle with the target in the center. If the rocket leans north west, increase power to the southeast magnet and decrease power to the northwest magnet.
Another idea would be to have a guy with a long stick on the barge ready to nudge it just a bit if it starts to tip.
We could start with our already phallic looking rocket and then have it come down into something that looks like the world's largest inflatable sex toy. Elon Musk might have trouble living that one down. :-)
Yes, there have been many proposals to somehow catch the rocket.
Bruce Perens.
Hard to splash down on the moon, Mars, asteroids and just about everywhere else we want to go. We'll have to get it right eventually, might as be now. Bonus benefit: cheaper than overhauling the engines every time. You'd think with them doing this at a third the cost of anyone else, WITH A PROFIT, that people would understand that they know what they're doing. Yes, there will be early failures, but this doesn't add that much cost, especially considering long term payoff.
Watch for Penguins, they eat Apples and throw rocks at Windows.
It's lighter to not reuse the hydraulic fluid.
It's an open loop system with pressurized gas pushing the fluid out and then it's dumped in the air. Pumps and whatever powers them have weight.
Remember that big fuel-required multiplier in getting any weight at all to 78 miles height and suborbital speed.
Bruce Perens.
The first stage is most of the rocket by weight. The second stage has one engine, while the first has 9. And as you can see from a photo, the second stage is much smaller.
What makes it recoverable is that it doesn't take much fuel to bring an empty first stage back down. It's really light when empty. They only use one engine out of the 9, for very short burns, to do that.
Bruce Perens.
You need three conditions:
1. Hit the target location
2. Minimal vertical velocity
3. Vertical orientation.
They met #1. It was coming in tilted (for varying amounts of tilt), and way too fast.
Who cares about the fuel efficiency of landing? A Falcon 9 launch costs about 50-56 million dollars - the fuel itself only costs about 200,000, or 0.4% of the launch costs. The cost of increasing the fuel load by a few percent to allow for landing barely even qualifies as a rounding error.
Meanwhile, all the extra mechanisms needed to turn a simple high-strength fuel tank into a transformer is almost certainly going to increase the mass so much that you'd need far more fuel to get the thing to the second-stage separation point in the first place - so net loss on fuel anyway.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
Musk's claim is that the barge didn't sustain any serious damage.
Screw self-landing boosters. What I want is a house made out of whatever the barge is made of, easily shrugging off what are essentially two direct rocket hits complete with massive explosion.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
I suppose magnetic/sticky harpoons might help (you don't want to damage it after all), sort of like guy-lines on an airship. I don't know about a shock-absorbing landing pad (your catcher's mitt) though - in the moments before landing the backwash would be subjecting it to forces exceeding those of the weight of the rocket itself - probably at least as difficult to tune any "give" to occur at the proper moment as i is to land the sucker in the first place.
Plus, as others have mentioned, Musk seems to have his eye on Mars. Landing a colony ship can probably only be done by rocket, and there won't be any special landing pads on Mars. Plus, for more terrestrial concerns, if he can master landing on a simple barge, he can land pretty much anywhere, which dramatically improves the value of his rocket design onte international market: any bit of flat, stable land is a potential cheap spaceport that his rockets can service.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
Rotating a thousand ton barge at 60 rpm would be interesting.
Faster! Faster! Faster would be better!
fuel needed for the landing is inefficient compared to a splashdown parachute recovery
The barge/ocean is just a temporary measure. The vision is twenty rockets launching a day and returning to the launch site to prep for the next launch.
There were about 120 rocket launches last year. SpaceX's mission statement is to reduce the cost of launches by 100x, and utilization rates go up as costs fall, so it's not just 100x more launches - twenty a day is probably very conservative if they hit their price targets.
Queue the folks who can't imagine what anybody would do with more than 640 launches a year.
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
Remember: seawater ruins everything.
Sorry.
I guess then you were not so lucky as to have rocket scientists in the family. I guess I'm not unlike many techies my age, whose dads worked in aerospace. My dad worked on the lunar module at Grumman. My father in law worked in the blue cube for Lockheed.
People think of me an the Open Source guy. But I have been getting space spoon-fed to me since before first grade.
Bruce Perens.
One would think that if they didn't know that the shuttle's boosters are made of inch-or-more-thick steel, while the Falcon's tanks are millimeter thick aluminum-lithium. And that the booster splashdown still tended to leave the boosters slightly out of round (which contributed to the problem Challenger had).
The extra fuel almost certainly weighs less than the necessary parachutes would.
-- Alastair
You think landing on a body 1/6 of Earth's gravity, without an atmosphere or weather, and under the control of a human is really comparable to landing on Earth, with full gravity, atmospheric weather systems, and all controlled by a computer?
Remember: seawater ruins everything.
One of those occasions where I wish I had mod points but don't. Mod the parent post up!
Seawater is extremely corrosive. Engineering the rocket engine to survive sudden immersion in seawater when very hot would add a great deal to the complexity and cost (and probably weight). And that's before you add the cost of engineering the rest of the vehicle to resist corrosion.
I'm old enough to remember when discussions on Slashdot were well informed.
Close to where I live are large intertidal mudflats. Every other summer some tourist drives a brand new four by four out there and gets stuck. And then, of course, the tide comes in. When the vehicles are recovered two or three tides later, they are insurance write-offs - the electrics, interior, and engine are all beyond repair.
You do not want to immerse something complex and expensive in salt water unless you really, really have to.
I'm old enough to remember when discussions on Slashdot were well informed.
When I first came here, this was all swamp.
Everyone said I was daft to land a rocket on a barge, but I built in all the same, just to show them.
It sank into the ocean.
So I built a second one.
And that one sank into the ocean.
So I built a third.
That burned down, fell over, and then sank into the ocean.
But the fourth one stayed up. And that's what you're going to get, Son, the strongest rocket in all of aerospace.
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff