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British Spaceplane Skylon Could Revolutionize Space Travel (ieee.org)
MarkWhittington writes: The problem of lowering the cost of sending people and cargo into low Earth orbit has vexed engineers since the dawn of the space age. Currently, the only way to go into space is on top of multistage rockets which toss off pieces of themselves as they ascend higher into the heavens. The Conversation touted a British project, called Skylon, which many believe will help to address the problem of costly space travel. According to IEEE Spectrum, both BAE Systems and the British government have infused Skylon with $120 million in investment.
"could" and "might" and "?" are standards in the click-bait tackle box.
Skylon's idea is to use oxygen from the air, rather than taking the oxygen as fuel for the initial part of the ascent. A well known idea that is being worked on elsewhere.
SpaceX started with a lot of money behind it, the support of NASA, and they are doing something very conventional (multi-stage LOx-Kerosene rockets) albeit better than the competition. Reaction engines are aiming at what they claim (with good reason) to be the biggest advance in propulsion since the jet engine. Snarky crap on slashdot is quick enough to write; R&D takes a long time.
They have built something. A precooler that can cool incoming air from 1000C to -150C as it comes into an engine intake at Mach 5, and is light and small enough to fit into an aircraft engine. This is the main part of the vehicle that is a big unknown, and they have shown it works in view of experts from government and industry.
Wrong on multiple points
It never becomes a scramjet. Not being a scramjet is in fact the entire point behind the last few decades of research. You can either try to burn fuel in a supersonic flow through your engine (scramjet) or you can slow the flow to subsonic and compress it so the fuel can burn properly (ramjets etc.) - problem is, this compression superheats the air. SABRE dumps the excess heat into the cryogenic hydrogen the vehicle carries so that you can operate an engine at high Mach number without its insides melting.
As for too many moving parts; they precooler itself does not appear to have any moving parts. It needs a liquid helium cooling loop to connect it to the hydrogen supply, but that isn't overly complex. Everything behind that is well established jet/rocket engine technology. Even if you assume that each precooler + bypass is itself as complicated as enough engine, the spacecraft only has as many "moving parts" as an ordinary rocket with 4 engines. SpaceX happily flies a rocket with 9 engines and will likely be able to reuse its first stage in a cost effective way.
The existence of failure modes is not a sufficient reason to predict high failure rates.
To get to low earth orbit, a vehicle needs to be travelling at 17,400 MPH (7.7 km/s). If it travels just bit faster, 25,000 MPH, you can head off wherever you want to go in space. Orbit is 2/3rds of the way to anywhere.
If I remember correctly, Reaction Engines got severely dicked by the UK government (pulling funding declaring the engines covered by the Official Secrets Act), effectively ending private development.
The design was promising but had teething issues, and has been carried on as a garage project all these years.
That they've managed to get this far given the hurdles they've had to overcome is nothing short of astounding.
I believe there is a quote from Arthur C Clark regarding this
"Every revolutionary idea seems to evoke three stages of reaction. They may be summed up by the phrases: 1- It's completely impossible. 2- It's possible, but it's not worth doing. 3- I said it was a good idea all along."
That's not to say that one should buy into every idea that someone is trying to peddle, but many of the technologies we take for granted today (aircraft, cars, PCs, engineered lumber, etc) were seen as prohibitively expensive, unnecessary and/or dead ends before they became widespread. Air breathing rocket engines of some sort are very likely to be the future of spaceflight, whether or not Skylon will be that future we will have to see.
I have followed Skylon for several years now. The engines are very interesting, in fact, the whole design, including the wings is very cool. The wings take the gravity load off, which for something that takes that long to get to orbit is quite an advantage.
They actually get more energy out of the hydrogen than they would get from just burning it. The reason is that they run the compressor on the temperature difference between ram air and the LH2 flowing to the engines. Burning hydrogen gives about 50 kWh/kg, it takes 20 kWh/kg to make it into a liquid.
You might note that everyone who has been given the full inside information, including the USAF, agrees that it will work as a SSTO. If anyone wants to build power satellites, Skylon is the only thing that is likely to get the cost to where power satellites could undercut coal.
End MGM. Get prospective parents of boys to Google: Men do complain