From what I’ve read they also hope to use the stored gasses for RCS. Sounds a bit complicated to me because you need to figure out a way to ignite the mixture for rapid firing adjustments but maybe they plan to use them as cold gas thrusters. Who knows.
You would need pretty good thrust though for the in atmosphere flip though so they must be trying to combust it at some point.
I’m really just saying that if they’ve calculated a way to do it in principle, they’ll probably make it work straight away.
While fluid dynamics is tricky business in space, the problem can definitely be turned into a more basic physics problem.
I was also thinking of a small centripetal rotational force, but I’m not sure if that’ll even be what they do or if it’ll be necessary. You could always create a flow inside the tank that creates its own centripetal acceleration and slowly fill the center region with a compressing fluid.
Then you just have to settle/dampen vibrations so that the system doesn’t create instabilities that result in chaotic motion.
You could also use a membrane (like a balloon) to displace the fuel with a compression fluid like helium. The geometry would be to inflate it from one end and it would expand such that it fills the volume of the tank. It wouldn’t burst since the pressure applied on equal sides would be equal and it would be designed to not be overly stretched. You’d just want it to not be near bursting as it conforms to the shape of the fuel tank. If there was no gas inside of it, it could be inside of the fuel tank without any gas in it taking on a “wrinkled” shape, taking up negligible volume until you start filling it with gas. Then, it would have a slightly conical inflated shape so that it hits the back of the tank and displaces the fuel from the back to the front.
I think that because their computation is so top of the line that they’ve already had this discussion, designed the system and I expect it will work pretty quickly after they test it. It’s not like hypersonic aerodynamics where you can only solve it computationally. You could actually solve my membrane problem analytically for many shapes. Same thing for simple fluid flows. This is why I don’t think it’s an issue. I don’t know their solution, but they almost certainly have one. And, if they have one, the physics of such problems means that testing it in a simulation will probably work well enough. Therefore, it’s probably one of the easier parts.
Rolls-Royce and Boeing invest in UK space engine - bbc
Sabre would work like a jet engine in the lower atmosphere and like a rocket motor in the high atmosphere
I remember hearing about this last year, nice to know they’ve got more money. It’s a proper sci-fi concept - I just hope it actually works! A true SSTO spaceplane would be awesome.
A Sci-Fi concept yes indeed. Stargate SG1 had the F-302 craft, which had atmosphere and space engines.
I’ve been following Reaction Engines for years and actually had an interesting chat with an engineer who contracted with them. The technology has been in the works for 30 years and while this money is certainly a huge boon, they’d already been granted £60 million by the UK government and European Space Agency.
The UK has been ramping up investment in the space industry over the last several years. Exciting stuff!
Not a lot of money for such a large tech project, but who it is coming from is important. Those players would not invest without a clear perspective to use the technology later on - so more investments are likely if the development progresses as intended. Good news for aerospace fans. ( And given that Rolls-Royce is almost the only survivor of the once very rich Aircraft manufacturing industry in GB, it is the right partner for this. )
A space plane would be pretty cool. The complexity of such an engine might be a lot to deal with though. I’m curious to see how it goes. I hope SpaceX gets more people trying to develop their own cheap space transport (which I hope comes from a wide variety of ideas).
The increase in capital and the increase in the market would be pretty awesome and would drive development.
I wish we could scrap SLS, double NASA’s budget, audit NASA to streamline it financially/bureaucratically and put NASA’s goal as assisting humans in landing on Mars and developing the first exploration missions to outside the solar system. NASA needs to be cool again. NASA shouldn’t be a conservative organization in the sense of the word that means reserved.
With BFR, NASA should be thinking about selling the space station, and then producing a craft meant to traverse the outer reaches of the solar system. I don’t see why BFR couldn’t go along with a large space tug. That is, you dock the BFR on the space tug with much more living space. Some project of that magnitude should replace SLS and, given SpaceX’s track record, public funds should be used to accelerate - and guarantee a BFR launch. A contract with an aggressive deadline that gives SpaceX freedom to do it how they would like to, and places NASA’s plans in SpaceX.
Then there would be more rocket engineers on the market to go help companies doing good stuff, or we might get other space startups. Really, killing SLS and diverting those resources would do a lot of good.
Furthermore, NASA’s budget is about to get a lot more return on investment with BFR.
I figure that the Skylon technology is best suited to high speed atmospheric flight. Orbital stuff should be left to rockets, which have demonstrated their ability to land.
That said, here’s a rather obscure technical video showing off some of Reaction Engines’ work on their technology. The first bit doesn’t show anything but a precooler test, but later snippets are more indicative of something happening.
Yep. And scrap NASA’s programs relating to a manned presence in space.
Nope. Double their budget and everything would just end up costing twice as much. Apollo. Space Shuttle. ISS. SLS. Never look to a group that lacks competitors to do anything efficiently or aggressively. That’s why we have capitalism. A group like NASA should be investigating the fringes of technology that companies - or even universities - simply aren’t prepared to tackle.
NASA remains a national welfare program for scientists and engineers. I like that it does that. We should have more rewards for smart people who want to investigate, learn and innovate.
Interview with Alan Bond, Managing Director of Reaction Engines, going into detail about the engine and the Skylon vehicle.
I’m inclined to agree…it’s possible the next generation of concordes will be powered by SABRE airbreathing only variant. It’s no surprise even boeing is now investing in them…their precooler tech is insane if it accomplishes what they claim. The largest obstacle to faster flight is the rapid cooling of the intake air. That’s where their value is at.
I used to be a huge fan of SSTO’s but I think now it’s pretty uneconomical in the face of current rockets until the majority of orbital velocity can be attained by using the atmosphere as propellant. We’d need to go a lot further than SABRE into the realm of scramjets which are still stuck in the future just past fusion.
Still, wouldn’t they make for a good first stage? This is assuming proportionally lots of SABRE-powered planes are built, so big economies of scale are made on them.
I look forward to watching the first real practical tests of this Sabre engine at the new test facility the BBC article says is being built in the UK. Especially the first test where it changes from air to rocket.
The reason SABRE and other air breathing engines are efficient is because their ISP’s are typically very high(in the multiple thousands of seconds) and as is typical, the trade off is that their thrusts are relatively low. I don’t know the numbers they are trying to hit, but I doubt Skylon has a TWR>1 and requires lift to fly. This means using it to lift a traditional rocket even as a “light” second stage is probably beyond its capabilities.
Indeed, the last time that I remember Reaction engines talk about how much money it would take to create a working prototype of the Skylon they estimated it would cost about £6 billion over 9 years.
Indeed, the last time that I remember Reaction engines talk about how much money it would take to create a working prototype of the Skylon they estimated it would cost about £6 billion over 9 years.
If your method of development is government funding without demonstration, you’re a fool of a businessperson. SpaceX only got funding because they had something that worked and was useful and were doing something that was already well tested.
It’s also really complicated, and probably expensive, and not as reusable as one might think. An improvement to Isp doesn’t necessarily correlated to an improvement in cost.
They have created demonstrators for parts of the system. Most critically the pre-cooler which is the most important technology.
But if you can get to orbit for 20 bucks a pound, do you even bother with a system like this?
I said it above but this is the entire value of their venture. It’s really incredible too if you watch their video showcasing it and talking about the numbers.
Aside from the fact that you can’t get to orbit for 44$/kg…Everything you can do today except get into orbit. It’s the first step in building turbines that can handle very hot incoming gases without destroying the turbine itself. This allows your standard air breathing engines to run hotter with higher pressures and faster speeds.
If you want to talk space exploration it’s the first technology demonstrator that will allow airbreathers to go from zero to the hypersonic regime(~Mach 5) without assistance. This is the flight regime where theoretically ramjets can kick in to propel you to the regime where scramjets work. This could allow you get very close to orbital velocities with only a small kick to put you into LEO. This is another way to have very very low cost to orbit…if the tech is ever developed and works as described. The very same thing can be said for any optimistic low cost to orbit flight vehicle.
Though you could argue that we’re almost there. I was bored and looking at rocket labs the other day and found their booking page for cubesats. It only(lol) costs 80,000$ to launch a 1U to LEO. That’s amazing. While the cost/kg of that is relatively high($80k-$40k/kg) the absolute cost of launching that is pretty low when considering that the cost of that satellite is around $50-$150k in the first place.
From my perspective every year access to orbit becomes a little more accessible. It’s a slow and steady process but it’s happening. Lower launch costs require higher cadence which requires more satellites which requires cheaper satellite manufacturing etc etc. As more people see it and go into the industry it becomes a little more accessible and a little cheaper.
It may not feel like a race but we’re in the the first couple miles of our space marathon where the finish line will be something really spectacular to see.
According to Wikipedia, for each engine:
Thrust (vac.) Approx. 2,940 kN (660,000 lbf)
Thrust (SL) Approx. 1,960 kN (440,000 lbf)
And for the vehicle:
Loaded weight: 325,000 kg[10]:6 (717,000 lb)*
Whether the engines will be that high and the vehicle that low is anyone’s guess. But those numbers allow for a thrust:weight ratio above one at sea level.
*Twice the maximum takeoff weight of a Boeing 747