After Thirty Years on Paper, Skylon Spaceplane Gets a Key Endorsement from the ESA

By Clay Dillow


The Skylon Spaceplane Reaction Engines

The Skylon spaceplane, a concept spacecraft that has been incubating in the UK for something like three decades, has all of a sudden taken a big leap forward thanks to a technical review by the European Space Agency. And if the money comes through--Skylon is a privately funded venture--this summer’s test program could quickly turn into a full-fledged ground demonstrator engine followed by a fifth scale model of one of the engines that would actually take to the skies.

The proposed Skylon would be reusable like the space shuttles but would dispense with massive, expensive rockets, taking off and landing via a conventional runway instead. Its novel integrated engine design allows the spacecraft to operate more like a conventional jet at lower altitudes, pulling in oxygen from the atmosphere rather than from external oxygen tanks. This drastically cuts down on its fuel load at takeoff.

At higher altitudes where the atmosphere thins, Skylon’s Sabre engine switches to full-on rocket mode and propels itself more like a conventional launch vehicle--though by this point it is already moving fast enough, and the air is thin enough, that it doesn’t need too terribly much fuel. Along the way it has to shed no external fuel tanks, allowing for what engineers are calling “single-stage-to-orbit” spaceflight. In this way, the reusable 275-foot Skylon could launch payloads of more than 16 tons into space with regularity at a far lower per-kilo cost than conventional rockets can.


But the hybrid air-breathing/rocket engine presents some serious challenges as well, and that’s what’s kept Skylon grounded for so many years. The engine must manage 1,000-degree high-speed gases flowing through its intake, then cool them prior to compressing and burning them along with hydrogen. This has led to the design of a novel heat exchanger that can take said gases and plunge them to -130 degrees celsius in just 1/100th of a second--no small feat. Engineers then had to devise a unique anti-frost solution that allows this heat exchanger to run continuously without freezing up.

By the ESA’s account, engineers working on the Skylon and its Sabre engine have done all of these things. ESA’s technical staff have seen it working on the lab bench and have given the engine their approving nod to go ahead with ground tests. That will happen this summer, when a scaled-up version of the cooling tech will be demoed.

That’s a big deal. If Skylon--or something like it--ever takes flight, engineers claim it could bring the roughly $7,000 per pound payload cost to launch satellites into orbit down to less than $500 per pound.



Извор: Popular Science

Aaaaa, ova vest me raduje. Ovo je sjajan projekat i smatra se naslednikom projekta HOTOL, sve je u stvari britanska prica (guraju, ne daju se, nalaze kintu itd); evo malo informacija iz proslosti:

"25 February 2009
Skylon contact on DRADIS

On the single stage to orbit (SSTO) development front, British scientist Alan Bond, formerly of the HOTOL concept and now classified RB545 air-breathing rocket engine that was to be mated to the HOTOL, has gotten go-ahead funding from the European Space Agency (ESA) and the government of the United Kingdom to the tune of a million euros.


Bond's company - Reaction Engines LTD - designed the Skylon SSTO as the spiritual successor to the British HOTOL, which was to be Great Britain's answer to the Space Shuttle. The cancellation of HOTOL was due to design issues stemming from the placement of the the RB545 engines.

With its massive engines placed at the rear of the craft, HOTOL's center of gravity was further back than normal airplane designs and it introduced some stability issues. A redesign of the spacecraft reduced the cargo capability of the HOTOL and affected the economics of the launch system. Skylon is the answer to the design issues of the HOTOL.

Placing the new SABRE engines outboard on wings moves the the center of gravity back to the middle of the spacecraft, giving ideal stability and cargo room, as the engines are no longer taking up space in the the main body of the spacecraft. Skylon is big - 82 m long, 6.3 m in diameter and a 25 m wingspan. Its dry weight is estimated at 41,000 kg and can carry 12,000 kg of payload. The heart of the system are the SABRE engines.

On Skylon, the oxidizer used is liquid oxygen (LOX). LOX is very heavy and for a standard hydrogen oxygen reaction, you need two oxygen atoms at 8 times the weight each of hydrogen for every hydrogen atom burned. For comparison, the Space Shuttle carries 106,000 kg of hydrogen at liftoff and 630,000 kg of LOX. 85% percent of the Space Shuttle's fuel weight is oxidizer. The good people at Reaction Engines LTD decided that carrying their own LOX was crazy when Skylon would be flying through it on its way up. The SABRE engine harvests oxidizer from the atmosphere during flight.

The SABRE engine is essentially a closed cycle rocket engine with an additional precooled turbo-compressor to provide a high pressure air supply to the combustion chamber. This allows operation from zero forward speed on the runway and up to Mach 5.5 in air breathing mode during ascent. As the air density falls with altitude the engine eventually switches to a pure rocket propelling Skylon to orbital velocity (around Mach 25)."

... i jos malo slicica- konstrukcija, ceo ciklus poletanja,orbitiranja i sletanja, preseci, itd...