Quote from: ChrisWilson68 on 06/15/2017 07:40 amQuote from: A_M_Swallow on 06/15/2017 07:23 amQuote from: ChrisWilson68 on 06/14/2017 11:35 pmYeah, governments could potentially want to own their own means of getting to orbit. I was just addressing the commercial part of the argument.I think it's questionable whether governments would rather spend money buying a launch vehicle built in another country rather than plowing money into domestic capability, but there is at least the potential some governments might.Boeing has made money selling aircraft to foreign airlines.Foreign airlines are businesses. The whole point of this conversation you're replying to is that governments might put money into space programs for non-business reasons. The point is that Skylon might be bought by governments for non-business reasons. So Boeing selling to airlines is not very relevant.Foreign airlines are frequently owned by their government making them little more than government departments. They exist to be flying adverts for the government - a non-business reason. So selling is very relevant.
Quote from: A_M_Swallow on 06/15/2017 07:23 amQuote from: ChrisWilson68 on 06/14/2017 11:35 pmYeah, governments could potentially want to own their own means of getting to orbit. I was just addressing the commercial part of the argument.I think it's questionable whether governments would rather spend money buying a launch vehicle built in another country rather than plowing money into domestic capability, but there is at least the potential some governments might.Boeing has made money selling aircraft to foreign airlines.Foreign airlines are businesses. The whole point of this conversation you're replying to is that governments might put money into space programs for non-business reasons. The point is that Skylon might be bought by governments for non-business reasons. So Boeing selling to airlines is not very relevant.
Quote from: ChrisWilson68 on 06/14/2017 11:35 pmYeah, governments could potentially want to own their own means of getting to orbit. I was just addressing the commercial part of the argument.I think it's questionable whether governments would rather spend money buying a launch vehicle built in another country rather than plowing money into domestic capability, but there is at least the potential some governments might.Boeing has made money selling aircraft to foreign airlines.
Yeah, governments could potentially want to own their own means of getting to orbit. I was just addressing the commercial part of the argument.I think it's questionable whether governments would rather spend money buying a launch vehicle built in another country rather than plowing money into domestic capability, but there is at least the potential some governments might.
Is there any fundamental reason the Blue Origin and SpaceX approaches would take any longer to turn around than Skylon would? I don't believe so. Bezos and Musk don't seem to believe so either.
Quote from: ChrisWilson68 on 06/14/2017 05:24 pmIs there any fundamental reason the Blue Origin and SpaceX approaches would take any longer to turn around than Skylon would? I don't believe so. Bezos and Musk don't seem to believe so either.BO plans to land on barge. It takes many hours for that barge to sail back to port. Then aditional time to unload the rocket and transport it back to launch site.Same with SpaceX for barge landings.And even when landing to a landing pad near the launch site, transporting the rocket from the landing pad back to the launch pad easily takes many hours, as special cranes need to be used etc.Towing Skylon at the runway can be done in minutes.So, until SpaceX/BO land directly into the launch pad, they have a fundamental disadvantage in this.
Probably this was already discussed, but what about a Stratolaunch-like concept with Skylon?Simplify the airplane, it "only" goes up to Mach 5 and then launch a rocket at higher altitude and speed than Stratolaunch.It could probably launch a larger payload than Skylon itself, without the need of all the other SSTO hassles.The major problem I see is launching a rocket from Mach 5. Unsure how it would work out.But even if it works, I see it only as a cheaper and faster way to use SABRE engines. Still I think it would not be as good as a standard rocket, especially regarding volume and lack of hold down test.
Worst, Skylon is LEO-only, meaning you need to add the cost of an upper stage for GTO.IMO, Skylon won't be able to compete with SpaceX/BE. Cost per Kg will be similar, but with smaller volume, smaller payload weight, limited to LEO and a huge upfront investment.
I think it's questionable whether governments would rather spend money buying a launch vehicle built in another country rather than plowing money into domestic capability, but there is at least the potential some governments might.
Skylon hasn't seemed to be on the agenda for a while now,
and especially since BAE took a share in the company. They've looked far more interested in the monetisation of the elements of the technology than a grand project like Skylon.
Also they only seem interested in TSTO in as far as they can sell the concept to someone like the USAF to pick up and give them funding to develop it further.
The researchers now at REL got burned by that with HOTOL. I'm pretty sure they are well aware of what they can and cannot do to retain rights over their inventions.
The new direction is finally creating opportunities to grow, and this moaning about BAE or TSTO is getting boring.Unless some multi-billionaire or foreign government was willing to swoop in and pay the costs upfront Skylon was never going to happen.
Quote from: ChrisWilson68 on 06/14/2017 11:35 pmI think it's questionable whether governments would rather spend money buying a launch vehicle built in another country rather than plowing money into domestic capability, but there is at least the potential some governments might.The British canned Black Arrow to buy launches from NASA.
Quote from: JCRM on 06/15/2017 06:05 pmQuote from: ChrisWilson68 on 06/14/2017 11:35 pmI think it's questionable whether governments would rather spend money buying a launch vehicle built in another country rather than plowing money into domestic capability, but there is at least the potential some governments might.The British canned Black Arrow to buy launches from NASA.Yeah, exactly, they cancelled owning their own launch vehicle to buy launch services from NASA.The argument for Skylon having an advantage because they're selling the vehicle doesn't hold if government either (a) are fine having someone else do the launch or (b) want to own the launch capability but want to develop it locally. Killing black arrow is an example of (a).Where's the example of a government not wanting to have their payloads launched by another country but being willing to buy the launch vehicles from another country?Of course, my asking for examples of that is a little unfair because historically launch vehicles have not been reusable, so buying them from another country makes you dependent on a continuing supply from that country. But still it means there's no evidence to support the thesis that governments would be willing to buy launch vehicles.In the long term, I do expect launch vehicles to become commoditized, just like airliners are today, and at that point, I do expect governments that want their own launch capability to buy them. But I don't think those commoditized launch vehicles will look like Skylon. I think they're more likely to look like ITS.I also think that as soon as launch vehicles are commoditized, all manufacturers of them will switch over to selling them to anyone who wants to buy (subject to ITAR-style rules that will leave out North Korea and friends). If somehow, it turns out a business can be made selling Skylons, at that point SpaceX, Blue Origin, and any other launch vehicle manufacturers are likely to go after that market too. So even if and when selling launch vehicles becomes a compelling business, I don't think Skylon will have an advantage.
Quote from: ChrisWilson68 on 06/16/2017 01:12 amQuote from: JCRM on 06/15/2017 06:05 pmQuote from: ChrisWilson68 on 06/14/2017 11:35 pmI think it's questionable whether governments would rather spend money buying a launch vehicle built in another country rather than plowing money into domestic capability, but there is at least the potential some governments might.The British canned Black Arrow to buy launches from NASA.Yeah, exactly, they cancelled owning their own launch vehicle to buy launch services from NASA.The argument for Skylon having an advantage because they're selling the vehicle doesn't hold if government either (a) are fine having someone else do the launch or (b) want to own the launch capability but want to develop it locally. Killing black arrow is an example of (a).Where's the example of a government not wanting to have their payloads launched by another country but being willing to buy the launch vehicles from another country?Of course, my asking for examples of that is a little unfair because historically launch vehicles have not been reusable, so buying them from another country makes you dependent on a continuing supply from that country. But still it means there's no evidence to support the thesis that governments would be willing to buy launch vehicles.In the long term, I do expect launch vehicles to become commoditized, just like airliners are today, and at that point, I do expect governments that want their own launch capability to buy them. But I don't think those commoditized launch vehicles will look like Skylon. I think they're more likely to look like ITS.I also think that as soon as launch vehicles are commoditized, all manufacturers of them will switch over to selling them to anyone who wants to buy (subject to ITAR-style rules that will leave out North Korea and friends). If somehow, it turns out a business can be made selling Skylons, at that point SpaceX, Blue Origin, and any other launch vehicle manufacturers are likely to go after that market too. So even if and when selling launch vehicles becomes a compelling business, I don't think Skylon will have an advantage.The UK is a trick question because it's the *only* country to give up its launch capability. You would get a country to adopt your tech in exactly the way BAE is doing with the Turkish TFX or Leonardo did with the T129 helicopter. They get to develop a customised vehicle using your engines and your consultancy to build up their skills.
Quote from: JCRM on 06/15/2017 06:05 pmQuote from: ChrisWilson68 on 06/14/2017 11:35 pmI think it's questionable whether governments would rather spend money buying a launch vehicle built in another country rather than plowing money into domestic capability, but there is at least the potential some governments might.The British canned Black Arrow to buy launches from NASA.Yeah, exactly, they cancelled owning their own launch vehicle to buy launch services from NASA.The argument for Skylon having an advantage because they're selling the vehicle doesn't hold if government either (a) are fine having someone else do the launch or (b) want to own the launch capability but want to develop it locally. Killing black arrow is an example of (a).Where's the example of a government not wanting to have their payloads launched by another country but being willing to buy the launch vehicles from another country?
I also think that as soon as launch vehicles are commoditized, all manufacturers of them will switch over to selling them to anyone who wants to buy (subject to ITAR-style rules that will leave out North Korea and friends). If somehow, it turns out a business can be made selling Skylons, at that point SpaceX, Blue Origin, and any other launch vehicle manufacturers are likely to go after that market too. So even if and when selling launch vehicles becomes a compelling business, I don't think Skylon will have an advantage.
QuoteI also think that as soon as launch vehicles are commoditized, all manufacturers of them will switch over to selling them to anyone who wants to buy (subject to ITAR-style rules that will leave out North Korea and friends). If somehow, it turns out a business can be made selling Skylons, at that point SpaceX, Blue Origin, and any other launch vehicle manufacturers are likely to go after that market too. So even if and when selling launch vehicles becomes a compelling business, I don't think Skylon will have an advantage.The advantage Skylon would have is that it was designed to be commoditised, with simplified integrataion and infrastructure, rather than it being retrofitted. Whether that design would work is a different matter.
Quote from: JCRM on 06/16/2017 07:54 amQuoteI also think that as soon as launch vehicles are commoditized, all manufacturers of them will switch over to selling them to anyone who wants to buy (subject to ITAR-style rules that will leave out North Korea and friends). If somehow, it turns out a business can be made selling Skylons, at that point SpaceX, Blue Origin, and any other launch vehicle manufacturers are likely to go after that market too. So even if and when selling launch vehicles becomes a compelling business, I don't think Skylon will have an advantage.The advantage Skylon would have is that it was designed to be commoditised, with simplified integrataion and infrastructure, rather than it being retrofitted. Whether that design would work is a different matter. It doesn't look that way to me. To me, Skylon's operations and maintenance would be likely to be much more difficult and expensive than those of two-stage vertical take-off and landing rockets like those of SpaceX and Blue Origin. Most of that is because single-stage to orbit requires more exotic technologies, and they tend to be more finicky.SpaceX/Blue Origin rockets only need kerosene or methane and LOX. Skylon needs liquid hydrogen. Liquid hydrogen is far more difficult to handle. The ground-side equipment for it has many more problems. Just look at how often the Space Shuttle was scrubbed because of liquid hydrogen issues. The greater temperature difference between liquid hydrogen and ambient temperature causes more thermal issues. The small size of hydrogen molecules means it tends to work its way into materials and make them brittle over time, or just leak out.Since Skylon is SSTO, it also needs special heat shielding technology that is very lightweight, and not used in the past. That is exactly what led to huge operational costs for the shuttle. The Skylon heat shield plans are very different from shuttle's, but the operational issues are a big unknown.More generally, with SSTO, it's harder to add mass to make parts more resilliant compared with a two-stage system, so it's harder to find ways to fix operational issues.
Quote from: IRobot on 06/14/2017 03:44 pmWorst, Skylon is LEO-only, meaning you need to add the cost of an upper stage for GTO.IMO, Skylon won't be able to compete with SpaceX/BE. Cost per Kg will be similar, but with smaller volume, smaller payload weight, limited to LEO and a huge upfront investment.The ESA had the development cost of the SUS (reusable Skylon Upoer Stage) included in the development budget.
Quote from: JCRM on 06/15/2017 06:05 pmQuote from: ChrisWilson68 on 06/14/2017 11:35 pmI think it's questionable whether governments would rather spend money buying a launch vehicle built in another country rather than plowing money into domestic capability, but there is at least the potential some governments might.The British canned Black Arrow to buy launches from NASA.Where's the example of a government not wanting to have their payloads launched by another country but being willing to buy the launch vehicles from another country?
Quote from: JCRM on 06/15/2017 06:05 pmQuote from: IRobot on 06/14/2017 03:44 pmWorst, Skylon is LEO-only, meaning you need to add the cost of an upper stage for GTO.IMO, Skylon won't be able to compete with SpaceX/BE. Cost per Kg will be similar, but with smaller volume, smaller payload weight, limited to LEO and a huge upfront investment.The ESA had the development cost of the SUS (reusable Skylon Upoer Stage) included in the development budget.Yeah, but that cost is not on cost per kg for LEO... so for GTO, cost is much more expensive because of the extra upper stage.
>The US relies on Russian made engines for it vehicles.
Being as a lot of this technology like in heat shielding falls under proprietorial information and therefore what we can know about it is limited I am not sure other than talking in fairly unhelpful very great generalities that there is much useful that can be discussed about it at this stage.
Yeah, but that cost is not on cost per kg for LEO... so for GTO, cost is much more expensive because of the extra upper stage.
...Skylon requires a lot of money and good engineering.A full reusable VTO TSTO needs several breakthroughs in physics which may (or may not) happen. ...
2) The repeated shock loads of slamming the airframe of the first stage into the ground, or if you're really unlucky into a pitching deck that's coming up as it's going down. I'm unaware of any similar industrial situation, or of any design standards that exist for it. What happens when you decellerate a large, high aspect ratio structure from X m/s to 0 m/s in << 1 sec? How good are the landing legs at smoothing this out? Will they have to be replaced every time as the price for protecting the rest of the structure? If that's ineffective what parts may be cracked off by those loads?