Doug Messier has a long but useful piece on the current state of affairs.
We’ve been trapped in a moribund, high-cost space-transportation industry for decades because the cost of each flight is so high that it doesn’t allow for anything resembling real flight test. That has traditionally meant that much verification of design is by analysis, rather than test, and design changes are careful and rare. Working on more of a software model with frequent upgrades, SpaceX has broken that mold, with probably every vehicle slightly different, continuously improving the system, but walking a fine line with risk of failure from something new and untested. But a software change rarely has unrecoverable catastrophic consequences, as a rocket launch can. I suspect that ultimately the finding will be that such a change had an unanticipated effect that caused the recent loss.
ULA can’t (or at least traditionally hasn’t been able to follow) the same philosophy because of the conservatism of its customer, which values reliability above all else for its expensive, critical payloads. This makes it difficult to quickly evolve its own designs (one of the reasons, no doubt, that Tory Bruno wants a new rocket, rather than a re-engined Atlas that he knows won’t be competitive with SpaceX). One of the challenges they will have is how to break out of that mode.
One could also say that extremely expensive launch also has “unrecoverable catastrophic consequences”. The cumulative difference in cost for the USAF between using only EELVs vs only F9/FH could easily exceed a billion dollars per year, perhaps two billion in some years. That’s a billion to two billion dollars worth of satellites that were not launched each year because the money went instead for launch services. That destroys a billion dollar satellite per year just as effectively as blowing it up in a rocket. This represents an enormous opportunity cost both in failing to expand currently satellite capabilities and in foregoing new types of satellites that were never developed because so much of the space budget went for launch instead of R&D.
I’m not sure how relevant EELVs are, though, since they’re going away.
This is why insurance was invented. It works for both crew and cargo. Informed consent should be a given.
This loss happened at a good time, providing serious focus when it will do the most good.
Granted that SpaceX has done amazingly well with the software model until (?) now, my first thought is whether it isn’t more suited to systems that start out as fully recoverable from the start. AKA hopefully less inclined to a total loss, more analogous in consequences to software, one hopes.
I’ve always pointed out that while SpaceX has taken the path “from orbit to reusability,” XCOR is taking the path from “suborbit, fully reusable, to orbit.”
my first thought is whether it isn’t more suited to systems that start out as fully recoverable from the start. AKA hopefully less inclined to a total loss, more analogous in consequences to software, one hopes.
Actually this can be an issue in software as well. Imagine someone goofed up with the software controlling an engine FADEC (cough A400M). Or even something more prosaic like someone who goofed up the software used to control money transfers or stock market trades. That can get really expensive.
It’s not uncommon for people to have insurance for some kinds of mission critical software. The way we usually try to prevent such errors from happening is with a *lot* of testing. Both low fidelity and high fidelity testing. Usually with three test systems where the one just before production simulates the production system fairly accurately. Which is what SpaceX are doing in the Texas test facility. Plus they also have some recoverability with the hold down prior to launch.
The problem is how to test Max-Q on the ground without an actual flight. Or hard vacuum. etc.
Though SpaceX are doing sterling work in showing just how little ELVs have been developed over the past half century (i.e. there’s still a huge amount of room for improvement), they are just scratching the surface with RLVs.
Nevertheless, given their approach (i.e. evolve an expendable into a reusable), I doubt they’ll make much progress in delivering a true RLV with airline like operations and duty cycles.
Only XCOR, as Charles points out, seem to be following the direct path towards a true RLV… unfortunately, with only a fraction of SpaceX’s funding.
Well I’m not sure XCOR’s path is the correct one. At least SpaceX had something that had orbital launch capability to begin with.
I think something like the X-34 actually fits better with what XCOR is trying to do.
Yeah. Remember how much time Orville and Wilbur wasted, on a system that didn’t even have trans-Atlantic capability?
Of course, you could also say SpaceX is on the wrong path because they don’t have interstellar capability.
Remember how much time Orville and Wilbur wasted, on a system that didn’t even have trans-Atlantic capability?
The analogy is decent enough. However can you imagine XCOR’s system scaling to the same degree? In terms of engine power or materials advancement or whatever? I personally also think that putting wings on a spacecraft is a waste of time. They are about as useful as a fish with a bicycle.
you could also say SpaceX is on the wrong path because they don’t have interstellar capability.
Yeah but nothing else we can currently produce has that capability either.
I think XCOR’s solution is fine for suborbital but that market is quite limited.
Can you imagine the Wright Brothers’ 12-hp 4-cylinder engine scaling to supersonic flight?
Are you opposed landing gear on spacecraft also?
The Wright Brothers started in a bicycle shop. So what?
So, your argument against wings was: “It’s as if an airplane manufacturer who had only done boats before tried to build a plane.” Do you read your own posts?
Now we have airplanes which are statically unstable.
If “now” means “for the last 111 years.” The Wright Flyer was unstable, requiring constant corrections from the pilot.
Propulsive landing’s major issues are in control hardware and software. The control hardware already exists. The software is the complicated part but its doable.
Avionics are *the* most complex part of a modern aircraft/spacecraft — much more so than the wings which bother you.
So much for the “KISS principle.” It isn’t the complexity that bothers you. That’s just an excuse.
Do people even care about it? No. The computer handles the flying. Same thing here.
Ah, now I see what this is all about. It’s not complexity that’s eating you; it’s the old prejudice against piloted spaceflight: Anything that resembles an airplane is bad because airplanes have pilots. If man were meant to fly, he would have wings. Ergo, no wings! 🙂
“it’s the old prejudice against piloted spaceflight”
Errr … I don’t think that’s why wings are disfavored by some RLV fans. It’s more that structure is expensive, and fuel is cheap. In addition, a landing pad is much cheaper to maintain than a runway. Oh, and wings cost you in drag on the way up.
The Wright Brothers started in a bicycle shop. So what?
You said spacecraft shouldn’t have wings for the because a company that built boats shouldn’t try to build airplanes. Are you having trouble following your own argument?
Now we have airplanes which are statically unstable.
No, we’ve had them since the Wright Flyer in 1903.
Do people even care about it? No. The computer handles the flying. Same thing here.
Ah, now I see where you’re coming from: Piloted spaceflight is bad. Everything must be done by robots. If man was meant to fly, he would have wings. Ergo, no wings!
For all the emphasis you put on complexity and the KISS principle, you ignore the complexity of the avionics, which are the most complex (and, often, most expensive) part of a modern aircraft/spacecraft.
None of this applies to propulsive reentry which only requires you to put a bit more fuel in the spacecraft when you top it up.
That’s not true. You need some place to put that fuel, so you have to make the tanks bigger. That means more structure — and as you say, structure is expensive. Adding fuel that’s only used for landing also decreases the payload (or delta-v). It’s uncertain which weighs more, wings or propellent. There are trade studies which have come down on both sides of the question.
The basic idea for jet engines is quite old:
https://en.wikipedia.org/wiki/Motorjet
So basically someone proposed a ramjet in 1908. It’s at least as old as that.
I’m ok with landing gear, or whatever, on spacecraft because the weight penalty for that is reasonably low, at least compared with wings. I still think propulsive landing makes more sense for orbital capable vehicles.
Henri Coanda flew a jet aircraft in 1910. The Hughes H-1 racer was a hybrid which got a significant percentage of its thrust from the supercharger exhaust rather than the propeller. The early centrifugal-flow turbojets were an evolution of superchargers, but they were soon replaced by axial-flow engines.
Propulsive landing also has a weight penalty. Maybe you want to wait for antigravity?
No need to wait for something nebulous like that. Wings only add unnecessary complexity to the problem. You are still thinking of how to build spacecraft from an airplane manufacturer’s mindset. It’s as if an airplane manufacturer who had only done boats before tried to build a plane. You are adding unnecessary crap to the system. KISS.
You’re displaying a common New Space prejudice: anything that resembles an airplane, in any way, must be wrong.
Your airplane/boat analogy is rather ill-chosen, given the fact that Boeing started in a boathouse. Since Boeing is now the world’s largest airplane manufacturer, I would have to say it didn’t hurt them.
A simplistic focus on parts count shows a lack of systems thinking. Design simplicity does not necessarily translate into simplicity of development, testing, and operations.
Scaled Composites chose a hybrid motor for SpaceShip One and Two due to its design simplicity, but getting the motor to work reliably has turned out to be a complex undertaking.
If parts count were the only figure of merit, you would have to say NASA was on the right path with Ares I. An expendable rocket requires fewer parts than a reusable one, and a solid rocket motor is simpler than a liquid engine. But such a system has great *operational* complexity due to the huge standing army needed to maintain it (and build a new rocket after every flight).
The most successful space transportation system will be the one that maximizes simplicity and economy of operations, rather than merely reducing parts count.
“Boeing started in a boathouse”
The Wright Brothers started in a bicycle shop. So what? How many seaplanes does Boeing sell today anyway? It is not surprising that people with a skillset on an old market, that has some overlap with a new market, switch markets. It is also not surprising that they try to apply old ideas on the new market. It doesn’t mean they make sense there though.
“Scaled Composites chose a hybrid motor for SpaceShip One and Two due to its design simplicity, but getting the motor to work reliably has turned out to be a complex undertaking.”
They were pressurizing a NO tank and it blew up. They tried to make it in-house without having prior knowledge about it. That was the problem. NO is not easy to handle. There are other oxidizers that can make a hybrid engine work other than NO.
Propulsive landing’s major issues are in control hardware and software. The control hardware already exists. The software is the complicated part but its doable. You will see.
I still remember people who distrusted fly-by-wire a couple of years back. Now we have airplanes which are statically unstable. Do people even care about it? No. The computer handles the flying. Same thing here.
“expendable rocket requires fewer parts than a reusable one, and a solid rocket motor is simpler than a liquid engine. But such a system has great *operational* complexity due to the huge standing army needed to maintain it”
None of this applies to propulsive reentry which only requires you to put a bit more fuel in the spacecraft when you top it up.
a landing pad is much cheaper to maintain than a runway.
There are runways all over the country.
Landing pads aren’t cheap. That’s why NASA is so anxious to find customers for its disused pads. It can’t afford to maintain them without outside funding.
Back in the DC-X days, one of the goals was to develop a vehicle that didn’t require that sort of expensive infrastructure.
Oh, and wings cost you in drag on the way up.
Not if your wing has an L/D ratio greater than 1.0. Which isn’t very hard to do. Don’t believe everything you hear at NewSpace conferences.
Landing pads aren’t cheap. That’s why NASA is so anxious to find customers for its disused pads. It can’t afford to maintain them without outside funding.
NASA has no landing pads; it has launch pads. Landing pads are in fact pretty cheap.
Pardon my naivete, but I’m trying to understand how lift created by wings will assist you on the way up (I do understand it creates a more benign reentry). In the Lynx flight video, Lynx goes near vertical almost as soon as it leaves the runway. If the lift vector is normal to the angle of attack, it will be mostly parallel to the Earth. I don’t understand how that force will help you get to space or near space.
It doesn’t, except to get the aircraft off the ground, and provide a strong control authority in pitch and roll.
Thanks for the follow-up, Rand. I’m still having trouble interpreting this statement (I know it’s not your comment):
Not if your wing has an L/D ratio greater than 1.0. Which isn’t very hard to do. Don’t believe everything you hear at NewSpace conferences.
I’m interpreting that comment as there is *no* penalty for carrying wings into space.
Well, it’s not true. There is a drag penalty, though it doesn’t last that long. And of course, the weight of the wings comes out of the payload.
SpaceX has been a phenomenon in the supposedly mature aerospace industry. Their success has been due to a phenomenal team of mostly young aerospace professionals led by a leader with unparalleled vision. They will recover from this with speed and continue to make history. I just hope they take time to tell us what actually happened soon!
No company will ever achieve better than two 9’s of reliability if they throw out their product after each use. There is only so much you can achieve with careful systems engineering. ULA has done an unparalleled job, but I have no doubt their hearts are in their throats on every launch.
On the other hand, evolving operations from an expendable approach rather than a reusable one means they may leave a lot of lessons on the table by not designing for maintenance and inspectability between flights. I could definitely see an argument like “the life leader flew 10 times so we’re fine going up for a 5th flight” when there is a plainly apparent problem lurking deep in the apparatus somewhere.
The market for launch is too small but can be made bigger.
The launch market gets bigger after we invest in the right development BEO. If self sustaining colonies can be put in space, then that’s the right development. Otherwise, we’d better get serious about mars.
That’s not true. You need some place to put that fuel, so you have to make the tanks bigger. That means more structure — and as you say, structure is expensive.
You were talking about operational costs now it’s this? You also need more structure for wings. Guess what: since the wings will experience a lot of heat on reentry (particularly for orbital vehicles) you will probably need insulation as well. Which was one of the most labor intensive parts in the maintenance of something like the Shuttle. So figure out some non-maintenance intensive wings for an orbital vehicle and then we can talk.
Avionics are *the* most complex part of a modern aircraft/spacecraft — much more so than the wings which bother you.
So much for the “KISS principle.” It isn’t the complexity that bothers you. That’s just an excuse.
Software doesn’t weigh anything and once development is done the cost to replicate it is essentially nothing. Does that answer your question?
If “now” means “for the last 111 years.” The Wright Flyer was unstable, requiring constant corrections from the pilot.
Guess what the lunar lander used propulsive landing and it was used in 1969. There’s one small nit with this. At orbital reentry speeds a human probably doesn’t have reflexes fast enough to cope. Oops.
it’s the old prejudice against piloted spaceflight: Anything that resembles an airplane is bad because airplanes have pilots
You are such a romantic. I could care less if someone is at the controls or not. The small problem, like I said, is reflexes at those kinds of speeds.
There’s a reason people went away from unstable designs after the Wright Flyer only to come back to them recently.