I was reading about the British Skylon SSTO (Single Stage To Orbit) vehicle and its SABRE engine described in Wikipedia.

The engine technology looks remarkable, if not revolutionary. Is this a unique effort, or is this technology also being explored by other nations/corporations? If so, what sort of timelines are they on?

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    $\begingroup$ It is not clear that Skylon will succeed. And the Brits are barely investing in it. Best of luck to them, hope it works, but odds are not in their favour. $\endgroup$
    – geoffc
    Aug 9, 2013 at 2:01
  • $\begingroup$ @Anthony X Yes, interesting topic though you might want to refine the question - whilst SSTO + Airbreathing/rocket hybrid is one combination it isn't obvious that the two have to be taken together. Given your comment to one of the answers it sounds like you are more interested in the latter. $\endgroup$
    – Puffin
    Oct 22, 2017 at 0:48
  • $\begingroup$ @geoffc Yes, a good point, though its all relative: being used to the normal approach here the Reaction Engines Story of the last few years makes it seem like they've finally hit the jackpot, a shoestring budget was what they had before that! $\endgroup$
    – Puffin
    Oct 22, 2017 at 0:51
  • $\begingroup$ @Puffin My question was really about the engine technology. What makes it interesting is the promise of enabling SSTO with runway take-off and landing profiles. $\endgroup$
    – Anthony X
    Oct 22, 2017 at 2:10

1 Answer 1


There is an entire Wikipedia article on the subject.

One could call the Apollo lunar module a SSTO vehicle, as it made it to lunar orbit with one stage. Probably not what you're after, but still.

Currently, there appears to be only one country other than Britain looking into the idea - the Romanians with their Haas 2C.

On June 1, 2012, Romanian organization ARCA announced that they are constructing an expendable rocket, named Haas 2C that will attempt to reach orbit in one stage. The rocket has 520 kg empty weight and can carry 15.5 tons of fuel. It will use kerosene as fuel and liquid oxygen as oxidizer. In Spring 2012 they have successfully tested a lightweight composite kerosene fuel tank. The liquid oxygen tank is being designed and it will also be made of composite materials. The launch is expected to take place in Spring 2013.

ARCA's site states that Haas 2C is an attempt at the Google lunar X-Prize. Their team page says that one of their goals is to create the Haas 2C to be capable of placing 300kg in LEO - quite impressive for a single stage rocket.

  • $\begingroup$ My question was focused on the SABRE engine technology, and whether there were comparable propulsion systems (presumably sharing its distinctive features) under independent development elsewhere in the world. My question wasn't really about achieving SSTO (regardless of launch location) so much as the hybrid (air breathing / LOX, turbine/ramjet/rocket) aspects of the engine concept, its implementation (including its precooler technology), and viability as an economic and re-usable surface to orbit propulsion system. $\endgroup$
    – Anthony X
    Sep 14, 2013 at 21:02

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