Slashdot Mirror
SpaceX Successfully Lands Its Rocket On A Floating Drone Ship For The First Time (theverge.com)
An anonymous reader quotes a report from The Verge: SpaceX has finally landed its Falcon 9 rocket on a drone ship at sea, after launching the vehicle into space this afternoon. It's the first time the company has been able to pull off an ocean landing, after four previous attempts ended in failure. This is the second time SpaceX has successfully landed one of its rockets post-launch; the first time was in December, when the company's Falcon 9 rocket touched down at a ground-based landing site in Cape Canaveral, Florida, after putting a satellite into space. Now that SpaceX has demonstrated it can do both types of landings, the company can potentially recover and reuse even more rockets in the future. And that could mean much greater cost savings for SpaceX.
A rock is a larger more masculine form of a rockette.
https://en.wikipedia.org/wiki/...
The smallest launch cost is fuel -- the largest is hardware. The majority of the hardware cost is for the 1st stage. So if the hardware of the 1st stage can be re-used, how is this not a win?
Somehow your logic does not add up. Fuel is nowadays a lot cheaper then a whole stage. Even if the payload goes down by a lot, it makes sense.
You are simplifying it to such an extent that you completely miss the point. The cost of the fuel is a small fraction of the cost of the launch - the cost of building the 1st stage dominates. When that stage is destroyed, it is an operational expense for that launch. When it is recovered, it is a capital expense with an additional smaller operational expense to refurbish and another expense to account for the reduced efficiency of the launch (some fuel held in reserve as you say).
Since converting the huge operating expense into a a huge capital expense that results in an asset that can continue delivering value minus some small additional operating expense, the net result is a more economic system.
All rockets fly with lots of margin (read: extra fuel) in case of unexpected anomalies during flight. The difference with SpaceX is, when the flight goes as planned, they can use that extra margin to recover an immensely expensive piece of hardware. What's more, not all payloads are using every last pound of capacity in the vehicle. If you can launch 90% of the weight at half the cost thanks to reuse, you've fundamentally changed the market.
This is like getting to reuse a Boeing 747 instead of scrapping it after a single flight. If you think that's just a stunt, you don't have much of an imagination. This is a game changer.
If that was the case, then why have their competitors shown interest instead of mocking it?
It's automated. No humans aboard. That fits the commonly accepted definition of drone.
1st stage is $60M. Fuel is $250K. You do the math.
The only accurate point in your post is that second stage landings may not prove practical, which is why there are no current plans to attempt that. Fortunately the second stage is a lot cheaper than the first stage, in this case the second stage is just one engine compared to 9 in the first stage.
This space intentionally left blank
SpaceX calls it a drone ship as well.
. . It is not obvious that doing this risky vertical landing is going to result in any savings at all. . . This is interesting but looks like a stunt.
I'll bet on the SpaceX engineers anytime over a random commenter on /. (regardless of the UID)
Do you really think that they haven't run the sums before spending all that time and effort perfecting something that you call "a stunt"?
I am Slashdot. Are you Slashdot as well?
That's the term SpaceX uses.
Dear lazy web, any higher quality video out there? Congrats SpaceX, this looks really impressive.
https://www.youtube.com/watch?...
The first stage costs $60 million to build.
The fuel costs $200,000 -- do the math.
I mean, if you don't mind $60 mil coming out of your pocket. The point is, re-use of the first stage enormously decreases costs per pound to orbit. If you can't figure that out, then I'm sorry, but, what are you doing on Slashdot?
If telephones are outlawed, then only outlaws will have telephones.
During the webcast they mentioned several times that they collect tons of data for each landing attempt, so yes, I expect them to successfully land a very high number of 1st stages going forward.
https://www.youtube.com/watch?...
I was gonna mark the parent as a troll, but really it's just uninformed.
https://science.slashdot.org/s...
Elon Musk says it takes $60 million to build the Falcon 9, and $200,000 to fuel it.
Steve Poulus, a former NASA project manager, suspects final costs could be driven below a million dollars.
So it's looking like a stunt that could be worth more than 95% of the first stage's $60M. That seems like a big deal.
They change the process after every flight, if the telemetry tells them they could have done something better. Just like they enabled the Dragon's parachutes during ascent on this flight, in case the rocket blew up. (The previous flight the 'chutes were disabled on ascent because it was assumed an explosion would be non-survivable, so when the Dragon capsude did survive the explosion, it was destroyed when it hit the water.) The odds of that making a real difference on any upcoming flight is minuscule, but it was a no-weight software change so why not? (Of course, they put considerable effort into making any software change reliable and predictable, unlike the vast majority of software out there.)
Continuous improvement. They may well change the process after this successful landing depending on telemetry, or may decide that it is good enough (for now).
Anyone know why they would come in at an angle and straighten up at the last moment? Is it actually easier to control that way, or is it to protect the landing pad in case of a list-second abort?
Nope, no sig
Uh... yes. They've changed the volume of on-board hydraulic fluid, they changed the leg lock-out mechanisms, they changed the landing approach angle, and probably a billion other things. Do you even follow SpaceX bro?
I'd go out on a limb and say they will probably stick 8 out of the next 10 sea landings, and no less than 9 out of 10 RTL landings.
Which has more power: the hammer, or the anvil?
Ditching it in the sea and recovering it causes too much damage to make it viable to refit. This was intended for the boosters on the space shuttle, but it ended up being cheaper to make new ones than fix the old ones.
Of course they could bring them down over land, but I think the unpredictability of exactly where they would land could be marginally terrifying.
Hey, that's "ASDS Of Course I Still Love You" to you, bud!
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
Seawater and final impact speed are two good ones.
Seawater inside a booster makes refurbishing it MUCH harder. With parachutes, you can't control the attitude at which the booster hits the surface, and those rockets are designed to be very strong for vertical loading, but horizontal loading would destroy it... like a beer can, it can support a load at it's top, but not it's side.
Keep in mind that they have to fly with that fuel anyways... they need the margin in case of engine failure or other recoverable scenario. So all they've really done is add the weight of some landing legs, fins, a few other sundries, and some intelligent flight computers to relight the engine and bring it back down... it's not as inefficient as people are making it out to be.
Which has more power: the hammer, or the anvil?
Actually the weld the rocket to the barge and tow it back over a few days. The drone ship can really only stay in one spot autonomously.
Most of their launches don't require the full payload capabilities of the rocket. If they're not going to use the extra payload mass anyhow, how does that reduce revenue?
A lot of good points have already been made, so I'd like to make one more note: they aren't doing second stage reuse here. There is a second stage but they are only reusing the first stage. Everyone knows second and third stage reuse has a lot of problems (more fuel required is only one of them). First stages cost more than other stages since the have the highest variability in what conditions they need to be able to function in (from near sea level pressures to near vacuum) and they are larger because they need to lift more total material. So just focusing on saving first stages already helps a lot.
Because parachuting will work only on earth and similarly dense atmospheric planets. Places like Mars and others where atmosphere is very little to non-existent, you will have to land by propulsion with something as heavy as this. As Elon Musk puts it, the ultimate goal is to create a technology capable of multi-planetary traveling.
Quite true, although it should also be noted that the ratio you provide isn't going to be the ratio of savings they get. There are fixed costs associated with turning the stage around, so the cost of re-use isn't just the fuel, but it's also the labor to haul the stage back, pay the boat crews, re-inspect the engines, etc.
It's still a major win even considering those fixed costs. Many predictions are coming in around the 1/4 to 1/2 mark relative to a brand new stage. That's SpaceX's savings: they have the option to price used stages anywhere between there and full price. E.g, just to make numbers up, say their costs end up dropping to 1/3 given the number of times they launch each state. They could price used stages at 2/3 to the customer, which both gets SpaceX more profit, and gives the customer cost savings.
They've actually landed successfully on land prior, this was their first success on a ship at sea. The last attempt it landed, then tipped over when a support leg broke, so i'd guess they reinforced that or something. I'm sure they'll have a few more fireballs, but my money is on them getting the landing down consistently very soon.
When I first started SpaceX I wanted to land a booster in the ocean. Everyone said I was daft to try to land a booster in the ocean, but I built in all the same, just to show them. First time, it crashed into the ocean. So I built a second and third one. They sank into the ocean as well. So I built a fourth. That landed, fell over, then sank into the ocean. But the fifth one stayed up. And that's what you're going to get folks, first stages that land on autonomous barges with weird names in the middle of the ocean.
Faster! Faster! Faster would be better!
which is why they're now saying it will cost 30% less, which is still disappointingly low, compared to elon's previous $60M minus $250K statements. and which is why you have to take what people say with a grain of salt (like launch timeframes!).
Also because you cannot use parachutes on Mars. SpaceX plans to eventually land on Mars, refuel and then take off to return to Earth.
Today's vices may be tomorrow's virtues.
Obviously now we have to see the recovery percentage that SpaceX can achieve, especially when they start landing Falcon Heavy on three barges, the one for the center booster being much farther downrange than the others. Seeing three land, two of them simultaneously, is going to be pretty amazing. If they can recover a lot of them, this completely changes the economics of space flight beyond the 30% discount SpaceX is quoting in the short term.
And don't forget that they are getting the Dragon back too, and Dragon 2 with its eventual ground-landing capability is expected to be reusable. Currently Dragon 1 lands in sea water, and the reuse they have so far is only of the pressure vessel, the capsule is stripped down to that and rebuilt.
Recovering the second stage is possible although not currently on the SpaceX roadmap. They would need to fly it with a heat shield.
Now, consider what it would take to land a Dragon on the moon and return. Not inconceivable, given Falcon Heavy and a few launches.
Bruce Perens.
60M is their entire rocket..... There are 3 parts to the rocket and their original (and still current) goal was for FULL re-usability. Since 33% of the rocket = 1/3, that completely matches up what they originally stated since you have to account for recovery, refurbish/inspection, and relaunch cost.
It's a long process and even SpaceX acknowledge early on the 2nd stage was more complex to recover and may not be possible. That said, the dragon capsule is slowly on it's way to re-usability so even if they don't accomplish that, a 50-60% cost reduction is still big considering they are currently the cheapest on the market.
After a couple hundred tries (yes, I suck), I finally got a strike! Now that I did it, I can go on to win all the bowling trophies ever!... said no sane person ever.
Yeah. Those are totally the same thing.
This is more like lining up the ball rolling thing that kids use, seeing where the ball goes, then adjusting your aim based on the result until you get a strike, at which point you screw the ball rolling thing into the floor.
Did they actually change the *process* they use
Yes. You think they just watched the others explode, shrugged, and said, "Huh. Okay, do exactly the same thing again, it might work this time"?
Or are they just getting better at the process they already had, due to practice?
Uh... I'm not sure what you think is going on here. Do you imagine there's some guy called Steve guiding the rockets in with a joystick, and he's only now got the hang of it?
systemd is Roko's Basilisk.
The only accurate point in your post is that second stage landings may not prove practical, which is why there are no current plans to attempt that. Fortunately the second stage is a lot cheaper than the first stage, in this case the second stage is just one engine compared to 9 in the first stage.
Even if they can't recover the second stage, if they can get reliable recovery/refurbishing/reuse of the first stage that'll completely change the economic equation. Say you can reduce the second stage cost by $1m by increasing the first stage cost by $1.2 million, today you won't do that because it's a net $200k loss. If you can reuse the first stage once for neglible fuel costs it becomes a (2*$1m - $1.2m)/2 = $400k profit per launch. If they can do it five or ten times, it's even more profitable. So I think there's a lot of potential improvements just redesigning to take maximum advantage of first stage reuse by making the second stage do less and cost less.
Live today, because you never know what tomorrow brings
Are you trying to spell Cthulhu? If so, back to the drawing board.
Blue Origin has been mocking them in the other way. "Hey, look at what we just did! What took you so long?" Sure, you had a sub-orbital launch profile (almost no horizontal velocity), popping off a tin can that came straight back down. Boy Scouts recover their Estes rockets all the time. SpaceX already did the landing thing with their Grasshopper rocket (and DC-X long before either of them), and the only reason they didn't take it higher was because they didn't have clearance to go higher at McGregor.
Falcon 9 has been on an orbital launch profile every time, sometimes even GTO, which is a lot harder to come back from. Even hitting the drone ship and falling over was harder than what Blue Origin did. A side-effect of having an actual useful launch profile is engines that can't throttle down to hover (Blue Origin can), so they have to do the much harder "hoverslam" maneuver. (zero vertical velocity at the same moment as zero altitude)
I will, however, give Blue Origin a few points for doing quick turnarounds. Their short-term objective is space tourism, and they're doing exactly what they need. It's just not nearly as hard as what SpaceX is trying to do.
#naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
Afaict they have attempted landings* on 6 flights of those two were successful.
Flight 14, failure due to grid fins ran out of hydralic fluid.
Flight 17, failure due to stuck valve
Flight 20, successful landing at the cape
Flight 21, failure due to landing leg issue
Flight 22, failure (and was expected to fail) due to coming in too fast due to a large payload.
Flight 23, successful landing on
So basically the devil is in the details. Each time a failure happens i'm sure they put a lot of effort into working out the details of what went wrong but what is not clear is how many iterations of failure they will have to go through before they get a reliable result.
One thing I would note is that they don't need 100% reliability. They just need sufficient reliablity to make the savings from reuse greater than the cost (payload reduction, landing location operations and repairs etc) of the landing,
* Defined here as attempting to land etiher a landing pad on land or a droneship. I don't count the drop in water tests as landing attempts.
note: i'm known as plugwash most places but i screwd up registering that here somehow in the past and now can't register
And since capital equipment /always/ has a depreciation, you can write off the depreciation instead of watching it burn up in the atmosphere.
Surely the burning-up-in-the-atmosphere approach qualifies as accelerated depreciation?
I don't care if it's 90,000 hectares. That lake was not my doing.
That's not really how rockets work. Sometimes a launch profile is compatible with secondary payloads, and so they sometimes do that. But often they're not, and so you can only launch to the one orbit. SpaceX doesn't control the satellite manufacturers operators: if the payload doesn't need the full payload, they can't just stick another satellite in there or tell them to make it bigger. If they could be putting additional payloads in the rocket to derive additional revenue, they would be. When they do the Orbcomm launches, they're launching lots of satellites at the same time, but then, those satellites all launch into very similar orbits.
Reusability on the first stage doesn't add terribly much weight anyhow: it takes a lot less fuel to decelerate a mostly empty stage than it does to accelerate the whole thing up to speed in the first place. It's also not a 1:1 relationship: 1 kilo of extra fuel does not subtract 1 kilo of mass from the potential payload. That would be true of the second stage, but not the first stage.
Since they can't really use that extra capacity anyhow, they might as well use it for cost savings, because reducing your costs is even better than increasing your revenue.
Elon said today in the post-launch press-conference that recovery meant a potential of 1/100 in present operating cost but that fixed cost would not change from recovery. He is trying to reduce fixed cost with additional automation and of course there are economies of scale. 30% is what they can start with and make a profit, which they have to do now. I believe they can achieve a significantly larger reduction over the long term.
Bruce Perens.
Even if they can't recover the second stage, if they can get reliable recovery/refurbishing/reuse of the first stage that'll completely change the economic equation. Say you can reduce the second stage cost by $1m by increasing the first stage cost by $1.2 million, today you won't do that because it's a net $200k loss. If you can reuse the first stage once for neglible fuel costs it becomes a (2*$1m - $1.2m)/2 = $400k profit per launch. If they can do it five or ten times, it's even more profitable. So I think there's a lot of potential improvements just redesigning to take maximum advantage of first stage reuse by making the second stage do less and cost less.
Also worth pointing out that those first-stage engines will have a limited number of flights they're good for. So on it's last flight, you stick the engine in a second stage. After all, you've got to get rid of your expired engines somewhere, so they may as well go in a second stage as a junkyard somewhere.
Each "time's up minus one" first stage yields nine expendable second stage engines, sorta kinda for free.
Two obvious things here. First, who are they going to sell that capacity to? A bunch of cubesats? The income isn't necessarily there.
Second, by this particular compromise in capacity they're trying to get both lower costs per launch and higher reliability of operation. There are some very significant benefits to this, if they can get it to consistently work.
Also worth pointing out that those first-stage engines will have a limited number of flights they're good for. So on it's last flight, you stick the engine in a second stage
The second stage engine has a different design, because it's optimized for operating in vacuum. I think a better plan would be to launch the first stage as disposable when the engines are getting near the end of their life, and use that disposable launch for a heavy payload.
For the Merlin 1C, the only difference with the vacuum (second stage) version is the nozzle - a much larger expansion ratio. Other than the nozzle, they're the same engine.
The Merlin 1D variant is more deeply throttleable on the second stage, but it's unclear whether this is just a configuration setting or substantive hardware differences. I would imagine the former as much as possible.
But in any event, we concur -- lots of useful things to do with engines on their last flight.
SpaceX, and the people in this thread, are comparing the vehicle cost to fuel cost, which is kinda cheating. It's not the cost of the fuel that matters, it's the cost of building the vehicle larger to hold that fuel -- and the fuel needed to launch that fuel -- that matters. So let's do the math!
Most data taken from http://spaceflight101.com/spac...
Basic info:
Stage 1: 23 tonnes structure, 400 tonnes fuel
Stage 2: 4 tonnes structure, 93 tonnes fuel
Payload: 13 tonnes
When launching, the first stage burns all 9 engines at full thrust for two and a half minutes. The re-entry burn and landing happen on a single engine, and from eyeballing the videos (including this one that shows the re-entry burn) appear to take about 30 seconds total. Assuming all burns are near full thrust (which is the best way to do it), that means the landing burn takes about (1/9) * (0:30 / 2:30) = 2% of the first stage fuel. Let's double that to 4% to provide a generous safety margin: that works out to about 400 * 0.04 = 16 tons more fuel.
This fuel is carried up to the moment that the second stage separates, so it subtracts from the mass of the second stage. Second stage plus payload weighs 110 tonnes: without the landing fuel, you could have scaled that up to 126 tonnes, a 15% increase.
So, landing the first stage reduces the payload SpaceX can launch, and thus the money they earn, by about 15%. In exchange, they recover about 75% of the cost of the launch hardware. So it's worth doing, even after you subtract off the cost of recovery and refurbishing. Maybe not the game-changer Elon Musk wants it to be, but it's a win.
Being able to inspect intact engines after a real mission would improve its development and refinement.
The Shuttle SRB casings were 8mm thick steel in order to withstand crashing into the ocean. The F9 skin is in the region of 0.4 mm aluminium. The Shuttle SRB had a fuel fraction of only 80%.
So, when you get to your car to drive to work in the morning, you load up every last pound of unused capacity with trash and dump it at the dumpster behind your office? If you don't, you have an operational problem at the outset. You should have bought a much smaller car, and kept your weight tightly controlled.
A successful API design takes a mixture of software design and pedagogy.