Why don't we have SSTO's already?

[Albert VDS]

Yes, but those are on the ejector seat itself and isn't pointed at the thing it's trying to safe.

But to be fair that's the least of your concern when everything around you explodes.

It's alright if you eject out of the craft when the engines cut off or something as undramatic, but I doubt a system could be designed for it which has a high certainty of saving the crew.

It surrounded by hydrogen and oxygen tanks, imagine an explosion like the Challenger. There's just no way to escape from something like that.

So I highly doubt Skylon will ever be manrated if it gets made.

Edited December 15, 2014 by Albert VDS

[Ziff]

Skylon is a hypothetical design. It might really well on paper, with highly optimistic margins and fantasy funding, but it is unlikely to ever fly, for reasons that have been explained in a dozen threads in this forum already.

Experience proves that aerospace projects ALWAYS end up at least slightly overweight, slight underpowered, and hugely overbudget. The truth is that nobody has the faintest idea how Skylon will perform exactly, what its margins will be, and what its operating costs are going to be.

It's an investment. And an investment calls for a return on investment. A fully-reusable launcher is only viable if you fly it frequently. There simply isn't a market to support frequent orbital flights. It's not a matter of interest, it's a matter of return on investment. At the current flight rates, vertical launch rockets simply offer a better return on investment.

Quite possibly. But is it NASA's role to spend billions of taxpayer's money on developing new transportation technology when there is no market to back it up?

Yes yes, I said planned when I meant theoretical/proposed. It may be unlikely to fly but that's not the point. The point is , MSTOs will always be the most efficient way to get to space if we don't try to build something better. They're only the best right now because it's the only option we have.

I agree that it's an investment and that the problem is governments investing the money don't see an immediate need or return on that investment. They've got no problem spending billions and billions just to be prepared to kill each other though.

There may not be a market right now, but that's because the cost is ridiculous. If the cost was reduced to be affordable you would have all kinds of people itching to go to space for the tourism. See the Earth from the heavens! Get engaged with the most beautiful backdrop ever created! Touch the skies and get closer to God so he can hear your prayers! (For those religious minded folk)

Right now space tourism is resting on the hands of the very few and very wealthy. If we were less interested in developing armies and weapons to kill each other, and more interested in exploring and developing the research and technology for space travel, then we might be looking at more programs that would reduce space costs and make space tourism more viable for the average person and there would actually be a return on those investments.

It's all conjecture really. Until some unstoppable global pandemic comes along, or some unavoidable catastrophe (Pick your favorite world ending movie here!) and then you'll hear people clamoring, screaming, and crying as to why we never developed low cost ways to get the hell off this rock.

[Frozen_Heart]

That's how most ejector seats work.

And every spacecraft abort system ever...

[tutrakan4e]

We've had SSTOs. They launched from the Moon and docked in oribt.

[Ziff]

Just Googled it... Are they serious? So they this is a safe idea to have a module hidden underneath cargo bay doors?

To get out safely in an emergency the craft would need to have zero rotation, the cargo bay door need to work and get out of the way and the explosion and debris needs to stay clear of the ejected passenger module.

So what can go wrong?

And yet millions of people get on board airliners every day that are equipped with escape caps- er.. parach- er.. dang.

[Albert VDS]

And yet millions of people get on board airliners every day that are equipped with escape caps- er.. parach- er.. dang.

Good point.

[Moar Boosters]

Yes yes, I said planned when I meant theoretical/proposed. It may be unlikely to fly but that's not the point. The point is , MSTOs will always be the most efficient way to get to space if we don't try to build something better. They're only the best right now because it's the only option we have.

I agree that it's an investment and that the problem is governments investing the money don't see an immediate need or return on that investment. They've got no problem spending billions and billions just to be prepared to kill each other though.

There may not be a market right now, but that's because the cost is ridiculous. If the cost was reduced to be affordable you would have all kinds of people itching to go to space for the tourism. See the Earth from the heavens! Get engaged with the most beautiful backdrop ever created! Touch the skies and get closer to God so he can hear your prayers! (For those religious minded folk)

Right now space tourism is resting on the hands of the very few and very wealthy. If we were less interested in developing armies and weapons to kill each other, and more interested in exploring and developing the research and technology for space travel, then we might be looking at more programs that would reduce space costs and make space tourism more viable for the average person and there would actually be a return on those investments.

It's all conjecture really. Until some unstoppable global pandemic comes along, or some unavoidable catastrophe (Pick your favorite world ending movie here!) and then you'll hear people clamoring, screaming, and crying as to why we never developed low cost ways to get the hell off this rock.

SSTO's are necessarily ever going to be the most efficient way going about things.The shuttle exposed a lot of inefficiencies in reusable space-craft which are still applicable for any future designs. Sure it sounds more efficient for something to be reusable, but they discovered very quickly they couldn't build many of the parts to be reliably reusable.

The engines weren't really reusable, they were refurbish-able. After each flight they had to be completely dismantled and serviced. The same with the tiles. Maybe they're good for another flight, maybe they're not. The only way to check was have highly-paid engineers spend a huge amount of time checking them.

Whatever savings they made from not having to rebuild was quickly used up by them having to check, refurbish and replace.

Innovations are being made in the field of material science all the time. Just because they're not using them to build further spacecraft doesn't mean they won't be useful in the future. That's probably the main thing we learnt from the shuttle: Not to build one until we've got good enough materials.

[Francesco]

This article: http://www.thecoolist.com/jet-future-will-reach-destination-just-4-hours/

Is it possible that Skylon will never become a launch vehicle, for technical and economical reasons, but instead SABRE engines will be used on some sort of next generation Concorde passenger plane?

[Kryten]

if you can't make an economic case for pushing mass into orbit, you most certainly can't make a case with the same technology pushing mass to Australia. Particular as the majority of businesspeople that were assumed Concorde customers turned out to be just fine with normal flights, and the rest got their own jets.

Edited December 16, 2014 by Kryten

[RuBisCO]

A) The development cost are horrifying

Getting the necessary delta-v in a single stage is a tall order, it requires very high ISP.

[magnemoe]

I'm guessing that the payload bay doors are forcefully opened while abort SRBs shoot the passenger module free. Like a giant ejector seat. It would then be logical to have parachutes on it...

Yes, do not understand why they not simply remove the doors and put the roof as part of the passenger module. Removing the doors would be pretty simple.

This would make it far easier to eject the entire module. No you would probably not be able to eject a hypersonic speed nor under reentry,

[magnemoe]

if you can't make an economic case for pushing mass into orbit, you most certainly can't make a case with the same technology pushing mass to Australia. Particular as the majority of businesspeople that were assumed Concorde customers turned out to be just fine with normal flights, and the rest got their own jets.

The problem with Concorde is that it only had first class priced tickets but it was an entire plane.

That limited the number of routes it could be used at as it had to have an high enough volume of passengers. And it had to be direct flight, if you was going from say London to Washington or Chicago you would be better of taking an normal plane going directly.

[xcorps]

And what market exactly does the military serve? The one it makes itself that would not exist without its own funding? Hmm, perhaps if NASA had a chance ...

Ugh. Strawman at its most limiting.

[NERVAfan]

And yet millions of people get on board airliners every day that are equipped with escape caps- er.. parach- er.. dang.

Yeah, LAS are only needed because rockets are unreliable right now. If you had a rapidly reusable rocket, you could test it enough to prove very high reliability.

[NERVAfan]

It's an investment. And an investment calls for a return on investment. A fully-reusable launcher is only viable if you fly it frequently. There simply isn't a market to support frequent orbital flights.

Not right now. But given development times, we're not talking about the market now but the market 10 years from now. By then, we'll probably have partial reusability, we'll almost certainly have Commercial Crew, we'll probably have more space tourism and Bigelow stations, we'll probably have big LEO satellite constellations...

Quite possibly. But is it NASA's role to spend billions of taxpayer's money on developing new transportation technology when there is no market to back it up?

Not right now, maybe, but IMO building the infrastructure for large-scale human spaceflight is what NASA human spaceflight should be for. The cost is tiny on the scale of the US government, and the potential rewards are overwhelming.

[Ruedii]

The reason we don't have true SSTO flights yet is simply because it's cheaper to risk damage to the recoverable stages than the cost of the added fuel to carry them to orbit.

[Nibb31]

Not right now. But given development times, we're not talking about the market now but the market 10 years from now. By then, we'll probably have partial reusability, we'll almost certainly have Commercial Crew, we'll probably have more space tourism and Bigelow stations, we'll probably have big LEO satellite constellations...

10 years from now, Space X will have some experience with first stage reusability. With a bit of luck, they might have managed to cut prices down to $50 million for an unmanned LEO launch, which is impressive compared to the $150 million it was a couple of years ago. Commercial crew will be winding down with the EOL of the ISS. They might be able to offer tourist tickets for $15 million per seat, but I don't think that price is low enough to maintain a sustainable business model.

Constellations will go up on a single rocket. You can launch 200 sats in 10 launches. It will keep lunch providers busy for a while, and it might compensate for the saturation of the GEO market, but it won't generate volumes to make an frequent-flyer SSTO sustainable.

Bigelow had no customers 10 years ago and they have no customers now. I don't see why they would have more customers in 10 years. The issue with the launch market is not really a matter of price. It's just that demand is not there. Those who need into space are willing to pay the price for it. Those who don't need it won't buy it, however low the price is. Cut prices in half, or even divide them by 10, it won't change the game.

Edited December 16, 2014 by Nibb31

[Frozen_Heart]

might have managed to cut prices down to $50 million for an unmanned LEO launch

The price at the moment is already only just over $50million. Hopefully 1st stage reuse can get it closer to $40million.

[cicatrix]

I'm a bit late for the discussion, but here's my 5 cents:

1) Rocket equation makes SSTOs less payload-efficient versus MSTO and that fact will always be true

2) You don't need a PhD degree in material sciences to deduce the fact that there's nothing that can be 100% reusable. Materials are subject to wear and there's nothing that can be done with that. So, you can't make a 100% reusable craft (meaning a mere re-fueling it to use again). The stresses materials are subject to when the craft is flying through the atmosphere (pressure/temperature) are VERY severe. You can't even call a Space Shuttle reusable because its heat-protection hull should have been completely replaced after each flight (thus subtracting from its cost-effectiveness). Even a perfect material has its limits and each subsequent reuse will wear off its reliability thus heightening the risks.

3) We came very close to the upper limits of chemical fuels potential. You cannot expect that a new super-efficient engine with fantastic Isp would be built on the old propulsion principles. Engines we have now are only slightly better than those from 1960s and there's a theoretical limit we cannot jump over.

[Nibb31]

The price at the moment is already only just over $50million. Hopefully 1st stage reuse can get it closer to $40million.

$50 million was the 2013 price. The current listed launch price is $61 million: http://www.spacex.com/about/capabilities

Yes SpaceX fanboys, the price has gone up! Inflation, infrastructure, marketing and a full flight manifest are to blame.

If reusing the first stage scrapes more than 15% off the listed price, I'll be impressed.

Edited December 16, 2014 by Nibb31

[King Arthur]

You can't even call a Space Shuttle reusable because its heat-protection hull should have been completely replaced after each flight (thus subtracting from its cost-effectiveness). Even a perfect material has its limits and each subsequent reuse will wear off its reliability thus heightening the risks.

The Space Shuttle flew many of its heatshield tiles repeatedly (after inspection of course). Some tiles tiles would need replacement, be it due to wear over time or damage or whatever, but the Space Shuttle didn't need all its heatshield tiles "complete replaced" after each flight.

I know that many people want to rag on the Space Shuttle for its sensitive heatsheld or that it wasn't all that cheap for being "reusable", but the Space Shuttle was definitely a pioneering reusable spacecraft.

[NERVAfan]

$50 million was the 2013 price. The current listed launch price is $61 million: http://www.spacex.com/about/capabilities

Yes SpaceX fanboys, the price has gone up! Inflation, infrastructure, marketing and a full flight manifest are to blame.

IIRC the increase is no more than inflation alone (obviously not between 2013 and 2014, but since they first put up the original price).

If reusing the first stage scrapes more than 15% off the listed price, I'll be impressed.

That would seem extremely pessimistic to me.

Elon Musk said the first stage is ~75% of vehicle cost. I really think vehicle cost is much more than 20% of the price.

(If labor costs made the difference, the Russians, with their enormously lower labor costs, would be several times cheaper.)

[NERVAfan]

10 years from now, Space X will have some experience with first stage reusability. With a bit of luck, they might have managed to cut prices down to $50 million for an unmanned LEO launch, which is impressive compared to the $150 million it was a couple of years ago. Commercial crew will be winding down with the EOL of the ISS. They might be able to offer tourist tickets for $15 million per seat, but I don't think that price is low enough to maintain a sustainable business model.

In 10 years, if reusability works out?

I'd expect them to be more like half of current price - $30 million for a F9, ~$40 million for a FH with all 3 boosters reused. Significant, but not utterly game changing.

But ... in 10 years there is a good chance the next, fully reusable, rocket will be flying (Elon Musk recently said 5-6 years; assuming slips, 10 years seems realistic). And that may really change everything.

Constellations will go up on a single rocket.

Only very small ones. Elon Musk was recently talking about a 700-satellite constellation.

Bigelow had no customers 10 years ago and they have no customers now. I don't see why they would have more customers in 10 years.

Because they would actually have something to sell... They are specifically waiting on Commercial Crew to be available.

The issue with the launch market is not really a matter of price. It's just that demand is not there. Those who need into space are willing to pay the price for it. Those who don't need it won't buy it, however low the price is. Cut prices in half, or even divide them by 10, it won't change the game.

Since no one has ever lowered launch prices very significantly before ... how can you (or anyone) possibly know that?

Sure, people will not suddenly launch 5 times as many commsats or whatever. That's not the point. People will find new ways to use space as the price drops to make it accessible.

[Kryten]

Elon Musk said the first stage is ~75% of vehicle cost. I really think vehicle cost is much more than 20% of the price.

Yes, but what does that 75% cost actually contain? It's not going to be components-in a company with such a large amount of vertical integration-and it's not exactly to be materials, so what's left? Labour. How do you eliminate labour costs? Massively reducing the construction workforce. Will F9R allow him to do that? It's not at all likely, given the limited number of times a rocket would be able to be reused. So where are the savings?

[Albert VDS]

@Kryten: I don't get why you don't see where the savings are.

Let's say it's cost $45 million(75% of the launch cost). It'll be less than that, because of profit and what not.

You've got a 1st stage which you reuse 6 times. Dividing the cost by 6 and the 1st stage cost changes to $750,000 per launch.

Add that to the remaining stages cost and you'll get a rocket launch which will cost $16,750,000.

Of course that would be in a perfect world where the 1st stage doesn't need to be rechecked and fixed.

But I doubt it would add an other $5 million to the cost.