4 ms·

Great way to never be competitive in rocket launch. Huge investment required for little benefit. The Skylon people (who emerged out of the largely unsuccessful

by nickik 6y ago

Great way to never be competitive in rocket launch. Huge investment required for little benefit. The Skylon people (who emerged out of the largely unsuccessful British government rocket program) basically invested this concept that was supposed to be amazing and basically hand waved all the insanely complex engineering questions away. Their original analysis for Skylon has already been beat handily by SpaceX. Watch Elon Musk talk in Britain where they ask him about Air breathing engines. His point is simple, if you are gone introduce a massive amount of new complexity, you should get a a massive payoff. And with these engines, this is simply not the case. Investing the same effort into simple better first stage engines, will likely result into a far better outcome. That is exactly what SpaceX did. Maybe for some future Hypersonic airplanes or something this could maybe have some use, but for rocket launch, I don't think so.

DrBazza 6y ago
The massive payoff from the wikipedia page: > and with the vehicle reaching orbit with more payload mass per take-off mass than just about any non-nuclear launch vehicle ever proposed. For comparison the Falcon Heavy can lift 68,000kg to low earth orbit [0]. Since we're talking HOTOL, an Antonov can lift about 350,000 kg [1] - it's not hard to envisage a working HOTOL craft lifting something easily in excess of the Falcon Heavy, and with less fuel, and probably less dependent on other factors (temperature, weather, noise, no complex launch sites and so on). Being able to launch close to suburban areas, which rockets cannot do is likely to be a game changer as well. I'd sooner fly from London to Sydney in a SABRE powered craft, than a giant exploding tube that Elon Musk is suggesting. Elon Musk is a good salesman, and obviously has a vested interest in promoting rockets over any alternative. I think it's a bit unfair to say: > basically hand waved all the insanely complex engineering questions away. when they're solving each challenge as it comes along, such as the working precooler. [2] I'd like to see this succeed. But you're likely correct. 0. https://en.wikipedia.org/wiki/Falcon_Heavy https://en.wikipedia.org/wiki/Falcon_Heavy 1. https://en.wikipedia.org/wiki/Antonov_An-225_Mriya https://en.wikipedia.org/wiki/Antonov_An-225_Mriya 2. https://www.reactionengines.co.uk/news/news https://www.reactionengines.co.uk/news/news
- nickik 6y ago
  > > and with the vehicle reaching orbit with more payload mass per take-off mass than just about any non-nuclear launch vehicle ever proposed. Sure but that is not a relevant measure. > Elon Musk is a good salesman, and obviously has a vested interest in promoting rockets over any alternative. He is also an engineer who had money to create any company he wanted to hand he didn't invest in an air-breathing engine. And as I said, transporting human from a to b might be one thing, but for actual launch it will not be competitive. > (temperature, weather, noise, no complex launch sites and so on) When you have nothing that is even remotely close to working, making all kinds of claims about how amazing it will be is really easy. Building a complex shaped air-frame that is supposed to hold liquid hydrogen is already incredibly complex. Then saying it will also be able to launch in bad weather, at any temperature without launch infrastructure on a standard airport. It will of course also amazingly stable. Color me skeptical that a team that has never managed to do much of anything could pull of a whole long, long list of highly speculative, incredibly innovative new concepts that have never flown before. And not only get it to work once, but actually survive reentry heating, land on a standard airfield and quickly launch again. > when they're solving each challenge as it comes along, such as the working precooler. [2] They are moving threw a whole host of complex issues extremely slowly and from the whole Skylon plane they have maybe solved 2% of the issues.

by nickik 6y ago

DrBazza 6y ago

The massive payoff from the wikipedia page: > and with the vehicle reaching orbit with more payload mass per take-off mass than just about any non-nuclear launch vehicle ever proposed. For comparison the Falcon Heavy can lift 68,000kg to low earth orbit [0]. Since we're talking HOTOL, an Antonov can lift about 350,000 kg [1] - it's not hard to envisage a working HOTOL craft lifting something easily in excess of the Falcon Heavy, and with less fuel, and probably less dependent on other factors (temperature, weather, noise, no complex launch sites and so on). Being able to launch close to suburban areas, which rockets cannot do is likely to be a game changer as well. I'd sooner fly from London to Sydney in a SABRE powered craft, than a giant exploding tube that Elon Musk is suggesting. Elon Musk is a good salesman, and obviously has a vested interest in promoting rockets over any alternative. I think it's a bit unfair to say: > basically hand waved all the insanely complex engineering questions away. when they're solving each challenge as it comes along, such as the working precooler. [2] I'd like to see this succeed. But you're likely correct. 0. https://en.wikipedia.org/wiki/Falcon_Heavy https://en.wikipedia.org/wiki/Falcon_Heavy 1. https://en.wikipedia.org/wiki/Antonov_An-225_Mriya https://en.wikipedia.org/wiki/Antonov_An-225_Mriya 2. https://www.reactionengines.co.uk/news/news https://www.reactionengines.co.uk/news/news

nickik 6y ago
> > and with the vehicle reaching orbit with more payload mass per take-off mass than just about any non-nuclear launch vehicle ever proposed. Sure but that is not a relevant measure. > Elon Musk is a good salesman, and obviously has a vested interest in promoting rockets over any alternative. He is also an engineer who had money to create any company he wanted to hand he didn't invest in an air-breathing engine. And as I said, transporting human from a to b might be one thing, but for actual launch it will not be competitive. > (temperature, weather, noise, no complex launch sites and so on) When you have nothing that is even remotely close to working, making all kinds of claims about how amazing it will be is really easy. Building a complex shaped air-frame that is supposed to hold liquid hydrogen is already incredibly complex. Then saying it will also be able to launch in bad weather, at any temperature without launch infrastructure on a standard airport. It will of course also amazingly stable. Color me skeptical that a team that has never managed to do much of anything could pull of a whole long, long list of highly speculative, incredibly innovative new concepts that have never flown before. And not only get it to work once, but actually survive reentry heating, land on a standard airfield and quickly launch again. > when they're solving each challenge as it comes along, such as the working precooler. [2] They are moving threw a whole host of complex issues extremely slowly and from the whole Skylon plane they have maybe solved 2% of the issues.