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Comment by martythemaniak | Hacker News Reader

Currently they have to throw away the rockets used for GTO missions (around half of them) and can only attempt landings on LEO missions such as the ISS resupplies. Given their last few landing attempts, it's pretty likely that they'll be able to land a rocket sometime this year, which means that starting next year they might be able to reuse all of their F9 Rockets.

A lot of customers may not want to fly on a used rocket though (no one knows the risks), so SpaceX may end up with quite a large number of rockets, which they'll have to fly to establish costs/risks/etc.

It looks like at least a some part of their satellite internet plan was meant to take advantage of this large launch capacity. I'm also very curious to see what the prices for a used rocket launch are. Rockets are obviously expensive, but so are the operational costs in setting them up.

Anyway, these are probably the most exciting times in spaceflight since the 60s!

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   > Anyway, these are probably the most exciting times in
   > spaceflight since the 60s!

Yes it is, and we get to use technology from the future this time :-). It is bittersweet for me, the opportunity lost to keep funding NASA at a reasonable level could have a lot of useful data in the 'bank' as it were, but by and large much of the stuff that makes what SpaceX does possible is relatively new. In particular the avionics and MEMs manufacturing has allowed the mass fraction of the operations bits of the rocket to plummet.

I'm still curious though how they got a 30% improvement, and if it was a retelling of the Merlin 1C -> 1D evolution of if this is really a Merlin 1D+. They have also hinted at a project "Raptor" which is a ginormous engine.

And finally it really puts a bad light on "Cost Plus" contracts and the folks at Boeing and ULA who have supplied launch platforms for the last few decades. Clearly nobody in the "old guard" really cared about space, they just wanted to keep the money flowing. I am profoundly glad that they are being shaken up. Perhaps some of the management there will actually listen to what the engineers have been proposing for years and years.

"It is bittersweet for me, the opportunity lost to keep funding NASA at a reasonable level could have a lot of useful data in the 'bank' as it were, but by and large much of the stuff that makes what SpaceX does possible is relatively new."

Minimally, the pintle engine technology came out of NASA work and I suspect much of their technical knowledge comes either directly or indirectly from NASA funding.

" Clearly nobody in the "old guard" really cared about space, they just wanted to keep the money flowing. I am profoundly glad that they are being shaken up."

I think many of their engineers cared. But their corporate culture doesn't seem that interested in spaceflight, or at least spaceflight beyond the status quo.

Where there are engineers feeling oppressed, there is opportunity to disrupt!

>It is bittersweet for me, the opportunity lost to keep funding NASA at a reasonable level...

We spent more than enough money on NASA to have been decades ago where SpaceX is today. Unfortunately, Congress sees NASA as a source of patronage funding and not a space agency. If it had been run as a space program the shuttle would have been cancelled in the early '80s when it became The Monster That Ate The Budget.

I may disagree about which programs should be cut or not, but I agree with your sentiment: we could have paid NASA 10x and not advanced significantly. It would have just all flowed into various Congressional districts. We're advancing in spaceflight because we have no other choice: the money's ran out -- years ago, really.

Political systems of organization (organizations of people set up based on the desires of the electorate and controlled by politicians) exist and act for political reasons. Getting to the moon was a political goal, not a scientific one. The shuttle and ISS were political goals. Even privatizing like we've done is a political act.

We really need to build a mass driver on Earth for cargo launches. It would not be crazy expensive, and it would make a huge difference in the cost of LEO construction. Our order of priority should be 1) reduce cost to LEO to 1/100th of what it currently is, and 2) make orbital construction costs as close as possible to other oddball ground-based construction costs, like building underwater or in Antarctica. If we can focus on dropping costs, there are thousands of industries and other actors that will do some really cool stuff with the tools we provide. But that's a really tough thing to sell politically. The real reason we have SpaceX is because nobody wanted to explain to the folks how we lost a huge amount of our launch capacity when we retired the shuttle.

I agree that we need to build a mass launcher. However, I don't think we need to build it on the Earth. I think we need to build it on an airplane.

Seriously, the limiting factor in how small you can make an orbital launch packet is atmospheric drag. The more atmospheric drag, the more mass to surface area ratio you need to reduce the losses to an acceptable level. The smaller you can make the orbital packet, the smaller you can make the mass launcher. The smaller the mass launcher, the smaller the capital expense. A small mass launcher also fits on a smaller airplane.

We already have plenty of airplanes capable of flying in the stratosphere which can mount a mass launcher of a few tons weight. If the goal is getting mass up there, it doesn't matter whether it is 1000 launches of 1 kg each, or 1 launch of 1000 kg. But 1000 launches of 1 kg each could be done with much less capital expense.

The whole reason we don't have a mass launcher is because it is perceived as too expensive. Sea-level, or even mountain-level mass launchers need to launch large packets by their nature. But a high-flying airplane could launch many smaller packets with a cost which is actually doable.

The rocket is paid for with its primary mission. Elon has said that the fuel is a very small cost compared to the entire launch, so I would assume the cost to refly a "used" rocket is going to be orders of magnitude cheaper than the original flight.

I could see SpaceX segmenting their customers into two tiers: mission completion sensitive, and cost sensitive, with who gets which rockets straightforward.

Unfortunately, they can not reuse the second stage yet and they might never be able to with Falcon 9. I think Elon has already stated as much. The payload penalty due to the required heat shield, thrusters, fuel and legs for the second stage would be too much.

For arguments sake, lets assume that the second stage was 10% of the manufacturing cost and the first stage was 90%. You could argue, that the engines are what's most expensive and the first stage has nine times as many. Ignoring the cost for lunch, landing, refuelling etc. you could at best reduce the cost by 90%, a single order of magnitude. Unfortunately, the first stage might be worth much more. I wouldn't be surprised if the cost distribution is closer to 50-50. The second stage has all the avionics, a special vacuum version of the Merlin engine and might be more weight optimised due to the larger effect on maximum payload.

Lets hope the Mars rocket (BFR) will allow full, low cost reusability. I'm sure SpaceX is working very hard on that.

I wonder if instead of letting the second stage burn up, they could dock them in space somewhere to serve as material and fluid storage. They might not work for long term cryogenic storage, but a ton of pure aluminum has to be worth something up there.

They launch to specific orbits desired by the customers. It might well be extremely expensive to move the second stage from these orbits to some common one where could dock.

Yes, definitely cost prohibitive from a fuel perspective to change orbits, but the vehicle could be safed for future use. I do not have enough information as to whether though would be valuable unless Tesla as some way to produce fuel on-orbit for the waiting, safed second stages.

Well, FWIW, it works in Kerbal Space Program. But as you said, this would require for the fuel to be brought from somewhere else than Earth's gravity well. Maybe Planetary Resources will find some kerosene on a near-Earth asteroid?

No it doesn't, not if you launch satellites where customers want them. Kerbal Space Program should really bring home the big fundamental about orbital mechanics: plane changes are really expensive.

There are ways to make plane changes cheap (do them high enough, use gravity assist, etc.) and they could be useful when shipping fuel higher from Earth's gravity well, but I admit, current space missions are nowhere near that complicated.

Also, while expensive, plane changes are still cheaper delta-V-wise than punching through the soup our atmosphere is.

You'd have to keep boosting it where it is, which means it needs extra thrusters. Otherwise it'll just decay.

Also, changing orbits is expensive. Remember you need to change both height and angle, and the delta-V is huge.

Bringing them back down is almost certainly the easiest option.

If the 2nd stage at least had a small solar panel and magnetic tether, it could (slowly) change orbits into something useful. Not sure what the weight penalty for a minimally viable system would be. For the 2nd stage, every gram counts, much more so than for the 1st stage.

If we could fuel tugs with material from off-planet, then it wouldn't be nearly as expensive to do this.

I believe they've said that the second stage is about 25% of the total cost. Not cheap by any means, but just being able to reuse the first stage will be a huge boon. Even more so for Falcon Heavy, which still has a regular second stage, but has three first stage cores.

It's going to be cheaper, but still in the millions, and not just because you still need to pay for a new second stage. There's also nontrivial cost associated with range safety, payload setup, and so forth (which are operations that still involve lots of highly trained personnel, with limited opportunities for automation because, among other things, the payloads aren't all alike).

Millions would be great, as it's currently a matter of tens (or hundreds) or millions. Order of magnitude can make a big difference.

Any sufficiently large quantitative change becomes a qualitative change. Orders of magnitude usually do that.

>The rocket is paid for with its primary mission. Elon has said that the fuel is a very small cost compared to the entire launch, so I would assume the cost to refly a "used" rocket is going to be orders of magnitude cheaper than the original flight.

Engineers have been scratching their heads for decades trying to figure out where all the money goes. For shuttle launches, depending on who's doing the accounting, fuel was something on the order of 2% of total launch costs. And the shuttle was reusable as well.

I think it's that disparity that attracted Musk to the rocket business in the first place. You look at the cost breakdowns and think "What? How can this be so expensive?" If everything goes his way he'll have cut the vehicle cost by a factor of at least 20 by the time he's done.

> A lot of customers may not want to fly on a used rocket though (no one knows the risks)

I am certain the insurers will be happy to take a crack at figuring out the risk.

That matters a lot. Whether or not you "want to fly on a used rocket," if your company can purchase a flight and insurance on a used rocket for a lot less than it can purchase a flight and insurance on a new rocket, you might be obligated to try it because of the decreased costs.

(I'm ignorant as to who actually buys the insurance for these flights, the customer or SpaceX or what, but I'm sure the point still stands)

Would you fly in a used plane? Eventually no one will care. These rockets will be able to go through hundreds of flights before being retired.

It's not a straightforward insurance matter since many many applications are time critical. If a rocket blows up they may need many more years until a replacement cargo can be manufactured, fitted into the launch schedule, etc. The coverage for that (specially opportunity costs, which are hard to measure anyway) might be too high, making the insurance premium larger than the gain provided by reusability.

I'd believe most companies could prefer [more certain] safety -- which just means SpaceX will have to work on increasing reused rocket numbers by whatever means.

Specially?

You are right though, that there are far more than monetary concerns to consider. Sometimes it seems as though people, particularly on HN, believe that money is the only thing of consideration in any endeavor.

All true. The first used F9 payloads will likely be Geosynchronous communications satellites, where the smaller payload is mostly fuel for apogee kick and station keeping, and the rest is mostly off the shelf hardware.

Alternately, operators of large constellations, eg. Iridium that can replace the payload relatively quickly and cheaply. Opportunity cost can be mitigated if some of the payload is intended as on-orbit spares.

> It's not a straightforward insurance matter since many many applications are time critical.

If you can put a dollar figure on the potential time loss, it's still a pretty straightforward matter.

If you're flying with a "we must get this in orbit ASAP or the world will catch on fire" priority then, eventually, one will probably pay more for that. (the government will contract out a series of flights so it will play out differently for them)

It's going to take some flying for that to all shake out. As others have pointed out, it's not obvious that the first flight will have the lowest risk. It will be the most expensive in the beginning because its risk is the best understood.

Being timely is pretty important in the satellite business, there are things like communication licenses which expire.

It may not seem like it, but launch costs are still only a fraction of the total system cost. Ground for example infrastructure is more expansive by a large factor. Even the sat manufacturing costs overshadow launch costs for most systems. That's why customers might prefer safety until reliability is proven. Cutting corners on launch can jeopardize the whole system.

The fact that payloads are so expensive is partially caused by the launches being so expensive, so reducing the launch price tag will cause reduction in payload costs.

It's not a straightforward question whether the risk would be higher with a used or new rocket. Machines this complicated have significant infant mortality, and it may well be that the second flight actually has lower risk of failure than the first. Only time will tell.

If most of the rockets make hundreds of flights, then there's probably a statistics that says the first flight is riskier than the tenth.

https://en.wikipedia.org/wiki/Bathtub_curve

Other than costs, another advantage of flying the first stage back is that they can be analyzed to see how all the components perform or wear, and the design improved based on the findings. It's harder to do that when you crash them into the Atlantic every time. Over time, this could mean that reusable rockets are actually more reliable than one-time use rockets, though only if you fly enough times to get the benefit of evolving the design.

> SpaceX may end up with quite a large number of rockets, which they'll have to fly to establish costs/risks/etc.

I assumed this was the motivator for their satellite internet backbone scheme.

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