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SpaceX makes aerospace history with successful landing of a used rocket (theverge.com)
425 points by smb06 on Mar 30, 2017 | hide | past | web | favorite | 107 comments

I heard that Musk said that the next goal is to get Falcon 9 total turnaround time to under 24 hours.

That's a direct dress rehearsal for the https://en.wikipedia.org/wiki/ITS_launch_vehicle plan, where it takes off and returns directly to its pad, where it's refueled and 2nd stage loaded on top, for immediate turnaround.

We're living in the fuckin' future.

It's kind of weird to think that it would be so reliable that it wouldn't even need serious inspection before flying again!

But I guess other vehicles like cars and trucks are in that category (they don't typically receive an in-depth safety inspection before and after each trip), so maybe rockets can get there too...

I had an in-flight emergency (kind of) today while doing a cross country flight with a friend who is a PPL. We lost the alternator and lucky for us the weather was really good, sans high winds. That means we had no instruments and no comms.... except the back up handheld radio and our cell phones. No harm, no foul and we landed safely...

I say that to say this; I would hope they are just really fast at inspections. There is a real reason to get them right. Failures happen, even to super analog tech.

I think its important to note that while you shoot for reusability, if the vehicle fails where it can complete is primary objective (but not return to pad), that's not a show stopper; SpaceX has an entire warehouse full of returned cores now. For ICT, same deal. Hope for the best, but if your core has a critical failure and must burn a bit longer to achieve orbit, thereby losing boostback and sacrificing itself, you start rolling out the next core to the pad as soon as telemetry tells you (if you're on the clock with colonists waiting in orbit for fuel before breaking orbit).

This is not without precedent; a Falcon 9 core previously had a failure of an engine in flight, and the vehicle recalculated the burn time on the fly to continue on with the primary mission.


Ultimately, it may be better to abort in such cases, and land with payload (assuming there's enough propellant left to do so), or even discard the payload. As re-usability becomes more commonplace, the cost of the first stage booster will dwarf the cost per launch, and we'll probably see space launches for increasingly lower value cargo.

The dynamic loads of a fully loaded Falcon 9 preclude an abort once it's off the pad; you are committed.

I'm not an aerospace engineer, but if one wants to comment, I'd be happy to be corrected. It already requires ideal conditions for stages to separate successfully.

I realise this comment is now over a week old, but could you clarify what you meant? I don't know the specifics of the Falcon 9, but the only tolerance problem I see is in the strength of the landing legs, supporting the weight of the payload when landed (any excess propellants can be burnt off). Obviously you could make them bigger at the cost of lift mass.

The weight distribution of a fully fueled and payload-carrying Falcon 9 prohibits it from attempting any sort of boostback burn back to the landing pad if an abort is needed. It would tear the vehicle apart.

It would be similar to a a fully loaded semi truck trying to turn on a dime.

Airplanes are the comparison that SpaceX uses.

Exactly. Airplanes get inspected between flights, but it takes hours, not days to do the inspections.

It does not take hours. Southwest turns a 747 around in 20 minutes. That includes baggage unload/reload, fueling, and pilot pre-flight.

Southwest doesn't fly 747s, only 737s.

inspections might be easily automated

What sort of benefit would an immediate turn around launch provide?

Not connected to SpaceX in any way, but I can speculate.

1. Drastically less capex for the same traffic volume. If you have enough business to be launching once a week and it takes you on average six months to get a rocket turned around, you need at least 25 rockets (probably closer to 35 to smooth out the peaks). If it takes you on average a day to get a rocket ready, then you only really need two (one and a backup).

2. Beyond being useful on its own, immediate turnaround means that you don't have to do much between launches, which means that you've cut down drastically on opex. It's not just that you can get a rocket ready in a day, it's that you can get a rocket ready with less than a day's worth of work.

3. Agility means that you might be able to take opportunities that might otherwise be unavailable due to short notice. Your probe only has an hour launch window every couple of years, and it's delayed so that it won't be ready until 2 months before? With other launch systems, you might have to cancel due to uncertainty. With SpaceX, no problem - as long as nobody else is scheduled for that day, you can always jump in if your probe is ready.

SpaceX also only has so much warehouse space, and they can't have too many rockets in the shop at the same time. That would limit how often they can do flights.

Exciting! I'd like to see the faces of all those people arrogantly writing off SpaceX and Elon Musk. He isn't just a flamboyant marketing man, just doing stuff NASA did 40 years ago or whatever sour comments I've seen directed towards the achievements of SpaceX.

It is very inspiring to see a man with a dream reach this far, despite being ridiculed for years. It wasn't supposed to be possible, but he did it anyway. From now on one can always point to Elon Musk if somebody tries to put you down and say something can't be done.

Of course most are not anywhere near the talent and focus of Elon Musk, but it proves what people often seem to discount that startups can make a dent and challenge the big established players.

I see the same when people discuss Tesla. People are very quick to write off Tesla believing it is only a matter of time before Diamler Benz, Audi, Toyota, etc knock them down with a superior electric alternative.

Personally I think we will see in both space launch and the car industry an iPhone moment, where long time established players eventually get destroyed or made irrelevant.

It has nothing to do with difference in talent, but when you work in an established company you know very well how slow it can be for a company to change their ways in fundamental ways. The change in priorities, strategy and mindset will come too late for many of the players.

Almost feels like, the Elon Musk cult is like a religion for the generation Y.

Napkin-math ...

Long-term, Falcon9 exists to fund Spacex' R&D for Mars. Until now, Musk has said <5% of Spacex budget goes to ITS dev. I expect that to change now.

1st stage costs $40m, targeting 10 flights = $4m/flight, amortised. Add another 2-3 million for refurbishment, storage, etc., and reusing the 1st stages should save Spacex ~$33m.

Shotwell, however, has stated that customers will receive up to 30% discount. On a $62m flight, that's a savings of <$19m ...

giving Spacex an extra $12-15m pure profit on every flight ... which I hope/expect to get channeled into ITS dev.

Spacex is already the cheapest in the industry, and they now have a 3-5 year head-start in reusability, they simply don't need to lower their prices more.

The obvious question: how much cheaper should this make it, per pound, to put something in orbit?

Sort of depends on the details, some of which we don't know (we don't know actual internal costs, for example, only external prices which include markup). Here's some quick napkin math though:

We know the price of a Falcon 9 launch is about $65 million, and we know that the hardware cost of the first stage is about 3/4 of the total hardware cost. Assuming everything has the same profit margin markup that puts the effective price of the first stage at $49 million. They've said they think they can do 10 launches per booster core, if so that puts the amortized price at only $4.9 million per flight. Add the $16 million for the 2nd stage and that gives you a ballpark figure of $21 million per flight with the same profit percentages they have today. Add a few million dollars per flight for operational overhead and the cost of other components and you're probably not far off a reasonable estimate for what they could offer, let's call it $25 million just to be safe. At 22,800 kg to LEO, that's $1000 per kg ($500/lb). How much lower that could go depends on how much profit margin SpaceX would want to shave off and how much overhead they have for reuse.

In comparison, the industry standard Ariane 5 can do roughly $8k per kg to LEO, the Atlas V is similar, the Proton is about $4k/kg.

What's the prospect for second stage reuse? I know they have talked about it but my understanding is it is much harder due to energies involved and payload margin.

My understanding is second stage is harder, first because of the rocket equation. Every Kg on the second stage is much more costly than an additional Kg on the first stage.

Second, the second stage needs to go into orbit before it can return. That's much more speed and a harder reentry.

Third, you have to deal with thrust. Falcon 9 has 9 engines, which means the landing burn can uses 1 engine for 1/9 of the thrust. This is still too much power and F9 currently needs to do a suicide burn. You can't do that with only one engine on a stage that is 1/10 lighter than the first one.

Fourth, second stage has a vacuum engine with a nozzle not fit for atmospheric use. It's so thin and flexible it would probably crumble or disintegrate upon entry.

You could parachute it assuming it survives reentry, which is the first hard problem. The second problem is that chutes have to be replaced and are very tricky to install to work reliably. Plus they're another component. Second stage being lighter helps with parachuting it down. Also have to calculate if the extra weight of the chute makes it economical still.

Hmm... well I doubt parachutes are any harder than landing a rocket on a barge, so I'm sure this could be done. Sounds like one possible path. The stage may sustain some damage on landing but it would allow at least some of its more costly parts (engines, electronics) to be re-used and the rest of the material to be recycled.

It's a lot more difficult. Every gram you add in reuse facilitating systems is a gram lost in payload, so every gram has to be incredibly valuable. That's a daunting constraint to deal with.

Consider the worst case scenario here. You have a launch to GTO where the upper stage goes out to geostationary orbit altitude over the course of several hours before returning to LEO. The stage needs to be able to have enough power generation to live that long (currently it doesn't), which probably means solar panels or bigger batteries. The re-entry burn will take a little propellant, which isn't a big deal but does reduce payload capacity again. The re-entry will require new avionics and thermal protection systems. Then landing will require new control systems to steer toward the landing site plus new engines and possibly new propellant storage for the landing. At this point the main engine can't be used because it not only has the wrong thrust, it won't even work at low altitude.

But that's not the worst part. The worst part here is that being in orbit the stage is now "floating" free from the Earth's surface, which means that it now has landing windows in the same way that there are launch windows into orbit. For a high altitude orbit like a geostationary transfer trajectory this is very problematic because you have to wait for things to line up, but you only get roughly two chances a day so you might be waiting a long time. Lowering the apogee would help (you'd probably be able to achieve a landing within a day) but that's costly in terms of propulsion.

The obvious easy way out of that mess is to move the problem boundaries by going to 3 stages. The 2nd stage would only push to LEO and re-enter after a once around roughly an hour and a half after launch. The 3rd stage could be fairly small with a modest propulsion system, it only has to boost payloads from LEO to GTO etc. so it could be fairly low cost and easy to develop. Plus, it wouldn't be used at all on LEO missions.

But that still leaves all the rest. Most likely they add draco/superdraco thrusters to the 2nd stage along with landing legs and thermal protection systems. The thrusters alone might be enough to provide attitude control authority through re-entry and landing. Adding all that mass and complexity will increase the cost of the 2nd stage, while, for the most part, lowering the payload.

But on the plus side, even with significant increases in stage cost and mass they should be able to bring the per flight amortized hardware costs due to the 2nd stage down from over $10 million to under $2 million.

With first stage reuse alone they should be able to lower their costs by up to a factor of 3 or so, with second stage reuse they should be able to lower that by a further factor of 2 or more, making it possible to provide launches for under $10 million.

Not much, because SpaceX is currently the cheapest launch provider in its category (except perhaps the Russians). And their capacity is maxed out. If anything they should put the price up.

Yes. One of Elon Musk's core goals is to make humanity a multi-planetary species. To do that, he needs to make a lot of money.

At this point, the other commercial orbital lift companies are basically cooked, it's a matter of time. Blue Origin could be an interesting player, but who knows.

The question is this: can he drive even more demand by lowering the price somewhat? That's an interesting question, and one I'm sure being discussed at SpaceX.

China is reportedly poised to challenge SpaceX in the next decade or two.

"poised" and "a decade or so" aren't very congruent.

All the more reason Musk should be printing money with his launch-price advantage now.

Elon Musk wants to be on mars in "a decade or two".

I don't think that's the question.

You're speaking of what they charge.

I'm curious (and fwiw I'm not the OP, so I have no idea if they were asking this... :) what it costs.

Put another way, I wonder what this does to their margins?

Another thing to think about is SpaceX's customers don't buy the rockets, they buy the launch. So every first stage a customer pays SpaceX to build, once it completes it main mission, is now a stage SpaceX can use for their own purpose

... like building a LEO constellation of 11,943 satellites.

Why would you want that much trash in LEO?

LEO in most cases decay by themselves as for small amounts of air still being present. This means that LEO trash will burn in the atmosphere sooner or later.

Trash in LEO goes away; trash in GEO doesn't. The LEO satellite constellation replaces (with much lower latency, and greater locality) a bunch of GEO satellites.

Because it doesn't have to stay there.

Depends on how many times they can re-use a core.

The upper limit comes from the fact that they are currently only reusing the first stage, and that the first stage core is ~75% of the cost of a launch.

So, if they can use a core n times, they get a % discount:

    2 38%
    3 50%
    4 56%
    5 60%
   10 68%
They are planning on additional future reuse, the next portion is probably recovering the fairings.

I wonder if a thrice-used rocket will prove to be less reliable than a brand-new rocket due to fatigue, or more reliable than a brand-new rocket because it's proven itself to not be a lemon.

This development is great. So much fun to watch.

There will probably be a bathtub curve, like with pretty much every complex system known to man.

Didn't they recover the fairings on today's launch?

They did: https://www.youtube.com/watch?v=jC3LQFpuzqs&t=12m19s http://forum.nasaspaceflight.com/index.php?topic=42544.msg16...

This one probably isn't reusable since it landed in the water. Their next goal is to make a floating "bouncy castle" to land it on.

> Their next goal is to make a floating "bouncy castle" to land it on.

Can't wait to learn what name they'll pick for it.

> And their capacity is maxed out.

Re-usable rockets should increase their capacity...

Is their capacity limited by rocket construction or pad operations?

It's a bit a both right now, but I think the constraints from launch sites become much more relaxed in a couple of years when Boca Chica opens up.


Is there a reason launch pads tend to be on a shore?

Rockets generally want to fly over unpopulated areas to avoid raining debris on people should they explode. They get a boost as well when flying east due to the earths rotation. As a result, launch pads are located in areas where the rocket will be able to fly east over an ocean or unpopulated area.

> a boost as well when flying east due to the earths rotation

This will slow the earth's rotation slightly. Future generations will rue our profligate wastage of earth's angular momentum.

If the hardware comes back down then it's returning the angular momentum on burn-up or landing. Only interplanetary hardware is robbing posterity of angular momentum.

Stop Global Slowing!

Or at least #SlowGlobalSlowing!

If that's a problem, then I'll be a happy ancestor

We can always launch more rockets the other way.

My understanding is to make it less likely to hit populated areas in case of a launch failure:



There's an energy benefit for some launches at lower latitudes, but that's separate from being near an ocean:


typically it's for if things go poorly - a lot less mess to clean up if it's on the bottom of the sea

Currently pad operations. Soon, building of second stages.

The Atlantic writes that launch costs are expected to be 30% lower (40 Million instead of 60 Million), butt customers currently only get 10% off: https://www.theatlantic.com/science/archive/2017/03/spacex-r...

In the short term SpaceX will not reduce their prices - they will simply make a larger profit.

When SpaceX has effective competition that can deploy a single ticket multiple times, prices will drop dramatically.

That might be one logical approach, but it's not actually true. "Flight tested" rockets already offer a 10% discount to customers, and they say the plan is to get to 30% eventually.

Did anyone ever state the discount SES got? To my knowledge all we got were vague notions.

In any case, considering the four-month refurbishment the reflown core may actually have ended up more expensive than a new one. That's okay for now. SpaceX offered a discount to get a customer to fly on it instead of having to pay the launch cost completely on their own. Currently I wouldn't say the discount is any indication about how much cheaper reflying a core currently is. But with the first stage being about ¾ of the launch cost there are of course great potential savings, which is where the 30 % come in.

SES explicity stated that they would not disclose the discount they recieved, but confirmed they recieved a discount.

No doubt it was hefty, because of first-mover advantage - SpaceX badly needed an entity willing to take the _perceived_ risk, and SES was not only willing but eager to do it. I bet they got a great discount.


Or maybe making it cheaper to fly will increase demand enough that it makes sense to lower prices to meet it

> SpaceX president Gwynne Shotwell has said that customers that fly on a used Falcon 9 could eventually get discounts of up to 30 percent.

For sale. One rocket. Only used once, on a Sunday. $2M OBO. Ask for Elon.

Cuts costs about 60%. A bit better than spacebshuttle economics which was more like 40%.

Spaceshuttle economics were $50k/lb, so not like SpaceX.

I once heard Elon quote these: cost of a launch is roughly $60 million. Assuming the rocket can be reused 60 times it'll go down to about $1000 which is what he wants. IOW, he wants to make space travel ad cheap as international flight travel.

Either you misinterpreted or he was being hyperbolic. There are lots of other costs involved in a launch that do not scale like the reusable first stage. A sub $10M launch cost is very optimistic and would be considered a stupendous success.

I heard the cost of fuel and other logistical things per flight is less than $300k but sorry guys can't find the video..

Fuel is ~$200k. "Logistical things" is much more.

Logistics is getting streamlined as well. Range safety used to take ~150 people per launch. The Falcon 9 is now responsible for its own range safety, and will terminate itself faster than a human would if it deviates from its ascent profile substantially. (This was developed by the Air Force in partnership with SpaceX)


> cost of a launch is roughly $60 million. Assuming the rocket can be reused 60 times it'll go down to about $1000

Don't you mean $1m?

Ah yes, he meant $1000 per person.

wow, a death row prisoner costs about $1m, now if they were offered freedom and a ride on a falcon 9..

but actually plenty of normal would want a potentially deadly ride into space wouldn't they.

Space Australia is best Australia

yeah a kind of space aussie :)

1000 people is 100 tons, is that a typical falcon 9 payload?

100 tons is 200,000 pounds, which is 4 times the maximum payload of the falcon 9, which is 50,300 (to low earth orbit). geostationary orbit is a little more than 10 times less at 18,300

How do they know how many times they can re-use the rocket? Do they xray it for cracks every 5 flights?

You measure how much stress is applied to critical components, which uses up some of their finite lives. From experiment and theory, we know how much "damage" is done to a part subjected to a given stress. Similarly we know how much stress on components is generated in each launch. Therefore we can take the total life of each critical part (determined thru experiment and analysis), and divide it by the reduction in life (= damage) for each launch, to get the number of remaining launches. The part with the lowest remaining life determines the life of the system.

I wonder if, once they get a rocket to the max calculated safe launches, which will obviously have some margin built-in, it would be sufficiently worthwhile to keep launching it with low-value payloads (or none at all) and actually test it to failure.

My intuition leans toward no, obviously because launches are very expensive in terms of fuel and other stages, but also because there's no guarantee the test rocket would be representative, so for it to be really meaningful they would have to repeat the experiment several times. Still doesn't seem inconceivable though.

For this rocket, the process for figuring out if they can use it and how was very complex. This rocket was originally flown for the CRS-8 mission on april 8th, 2016. So it took them just shy of a year to ensure that this rocket could be reflown, and that they felt comfortable putting a customers payload on it. They also fired it on the ground many times, and I would imagine checked it for every imaginable component failure.

How ever, for the future, only time will tell how confident they will be able to be in the re-usability of their rockets. Most likely they will retire this rocket, as with the one that was first landed, and put it on display somewhere. After they research it, of course.

Minor correction, Gwynne said that this rocket only took 4 months to inspect. The rest of the delay was due to pushing the launch schedule back after one of their rockets exploded, with payload atop, during testing.

You are correct, they are retiring this rocket. In fact, SpaceX is giving a piece of the rocket to SES to hang in their conference room.

Sometimes I think SpaceX is landing stages so it can put them in museums, parking lots, and conference rooms.

Did they say why they're retiring this stage? A commenter at Ars said they spent a lot of time bringing it up to the latest rev. Seems like a shame not to fly it again.

Because once you have shown it is possible once, it means it can be done again. Why destroy a piece of history when you can destroy number 2 trying to fly it a third time?

They most likely spent the time bringing it up to the latest rev because of the performance improvements and increased reliability of the newer version. They didn't really care about how much time it took to get the second one to fly, as long as they could get it done. This was a really big milestone for their future plans, so it didn't really have a monetary or time limit.

Because its historic. Latter ones will not "suffer" this fate.

They estimate based on data. The biggest constraint at the moment is probably not anything that most people would think of like fuselage strain, it's the engines. The engines burn kerosene and they often run fuel rich, which leads to build up of residues (coking) in the plumbing. This is very difficult to remove and reduces the effective lifetime of the engines.

Once they get this generation of rockets settled into a pattern of high reliability reuse they'll look toward future improvements which will involve switching fuels (from kerosene to methane). LOX/Methane doesn't have the same coking problem so it could enable rockets with much longer lifetimes (a hundred or more flights per stage) and corresponding cost reductions.

Also, at that point the development cycle fundamentally changes because then you can match the airplane cycle where you build a few prototypes or test vehicles and then put them through their paces. Since you expect the vehicles to survive all the time (versus being lost routinely) you can achieve much lower development costs along with much higher reliability.

Or you could chemical wash off the coke if it's economical instead of changing fuel. Depends whether LOX/Methane is strong enough and the hardware still as easy to reuse, fuel and not prone to failure.

If it were that easy they'd be doing it already. It's not that easy.

Ya. I imagine they'll simply swap out the Merlin engines for scaled-down Raptor engines once those are fully ready.

Blue Origins rockets are rated 100 usages. Same as space shuttle.

Blue Origin hasn't flown to orbit yet - they have a sub-orbital rocket, and future plans for more.

Also Shuttle engines were practically rebuilt every launch.

Does the mean the amount of space vehicles (satellite, space stations, transport space crafts etc) will explode in next few years? I wonder if there any infrastructure to support this.

Thank you for making progress for humanity. Being useful haha.

edit: damn I could imagine something like a long assembly line, one building is a massive x-ray machine, rocket slides into it like a sub-sandwich going into a Quizno's oven, parts get pulled out, replaced with robotic arms, refueled, payload attached, stands up, boom back into space! haha

It would be awesome if much more capital was assigned to the space industry. Imagine a whole ecosystem of space companies both competing and cooperating.

Blue Origin has reused their Shepard rocket 4(?) times. Their rockect has not gone into deep space.

These are not really comparable. The Shepard rocket is sub-orbital and achieves something like 1/5 or less of the same speed as the Falcon 9.

It's also not carrying a giant payload and 2nd stage.

> Their rocket has not gone into deep space

Nor has Falcon 9. It would be more correct to say that no Blue Origin rocket has been to very high energies though, much less returned from them.

It is not space vs. deep space. It is space vs. orbit. Orbit means having the speed to not fall back to earth.

To be fair, Falcon 9 stage 1 has never been to orbit either.

True enough, but it's going an awful lot faster since it's aimed for orbital trajectory to inject the 2nd stage. So, it has tremendous horizontal velocity. Shepard, by comparison, just goes straight up (vertical only), so it's total velocity is far lower.

Falcon is in a totally different class of difficulty and complexity. I mean, the grid fins caught on fire and began to melt. That gives you a good idea of what sort of forces are involved in the descent.

Stage I is capable of reaching orbit with a small payload, adding stage 2 dramatically increases how much mass you get to orbit. However, stage I is expencive enough they are not going to waste one without an upper stage.

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