Photograph via snooOG

Skylon is a design for a single-stage-to-orbit spaceplane by the British company Reaction Engines Limited (REL), using SABRE, a combined-cycle, air-breathing rocket propulsion system, potentially reusable for 200 flights.

orbital maneuvering system, heat exchangers, HOTOL, hydrogen-fuelled aircraft, LOX, unpiloted, ceramic composite skin, precool, British government, Alan Bond, reusable launch system, British Aerospace, Rolls-Royce, University of Bristol, ESA, SSTO, ramjet, UK Space Agency


Welcome to /r/Skylon, a community focused on discussing all content related to the future Skylon spacecraft.

What is Skylon? Skylon is a future spacecraft being designed by a British company called Reaction Engines Limited (REL). If successful, it will offer cheaper access to low earth orbit in in a single stage. It will use a new engine class called SABRE, which is a combined-cycle, air-breathing rocket propulsion system.




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Does anyone know how much thrust Skylon will produce?

By this, I mean max thrust from both engines combined.

14:01 UTC


new heat record!


damn.they already get beyond the plan,and by 12.6%,it really is something.i just hope that these achievements bring more public/private money.

17:04 UTC


it's been a long time!



and wanted to quote someone in the forum of NASAspaceflight:

-1. Ammonia is globally one of the top 10 most commonly produced chemicals and well trodden handling and transportation procedures already exist for it. The main risk is ammonia release in enclosed environments.

  1. Compared to hydrogen as a fuel, ammonia is much more energy efficient, and could be produced, stored, and delivered at a much lower cost than hydrogen which must be kept compressed as a cryogenic liquid. Although not as powerful as other hydrocarbon fuels, the raw energy density of liquid ammonia is 11.5 MJ/L at room temperature 13MJ/L at -50C°, which is about a third that of diesel.

  2. At standard temperature and pressure, ammonia is less dense than the atmosphere and has approximately 45-48% of the lifting power of hydrogen or helium, so in an open environment like an airfield/airport it will quickly disperse upwards and will not be deadly.

  3. Liquid ammonia has a very high standard enthalpy change of vaporization (23.35 kJ/mol, cf. water 40.65 kJ/mol, methane 8.19 kJ/mol, phosphine 14.6 kJ/mol) and can therefore be used in laboratories in uninsulated vessels without additional refrigeration.  So liquid ammonia can be used in aircraft fuel tanks with little venting.

  4. Ammonia does not burn readily or sustain combustion so it is less flammable than jet fuel or hydrogen.  Its auto ignition temperature is 651 deg C so it will burn in a combustion chamber.  That is partly why ammonia has to be partially decomposed first, so that the hydrogen can be ignited in a combustion chamber at room temperature to start the combustion process.

11:26 UTC


Skylon reimagined as an long-haul executive spaceplane

I propose that at least the first version of Skylon be developed for long-haul executive transport to compete with private jets. It would work like this:

  • Skylon takes off from any international airport.

  • Fly subsonic until over a large body of water so the sonic boom isn't disruptive.

  • Go supersonic and burn to achieve a suborbital trajectory, leaving atmosphere while in coast phase.

  • Turn the engines back on at the end of the suborbital hop and fly subsonic to the destination airport.

Changes that would need to be made:

  • Make Skylon capable of takeoff and landing from most international airports without being too loud or hazardous.

  • Make Skylon able to go back to conventional jet engines for a bit after the burn so it can fly to and land at its destination airport.

  • Alternatively, make Skylon capable of water takeoff and landing to avoid both problems above, though this has it's own issues in addition to a last-mile problem.

Advantages over their current business model of orbital launch services:

  • No longer need hardly any payload capacity, simplifying the concept dramatically.

  • No longer need to worry about reentry heating and achieving orbital velocity, since only a suborbital hop is required.

  • The trip would be maybe an hour or two compared to 10+ hours on a private jet. Saves time and therefore money.

  • Has applications for time-critical delivery like specialists, organs, and even military personnel. In some cases this would be infinite value since there is no comparably fast alternative.

  • Even if it's so expensive that it's not economical, some billionaires will still want it as a status symbol. A G650ER has nothing on a freakin spaceplane.

  • Would be a unique marvel of engineering and a source of pride for Great Britain, much like Concorde. Imagine if at the next G20 Summit, the US president shows up in a 30-year-old 747 and the UK Prime Minister shows up in a freakin spaceplane.

Competition for a long-haul executive spaceplane would be as follows:

  • Private jet - much cheaper but also takes much longer. A Fortune 500 executive's time would probably be worth the Skylon operating costs.

  • Upcoming supersonic jets - these will still mostly have the problem that they can't go supersonic over land so they're really only good for trans-Atlantic or trans-Pacific flights and still are extremely slow compared to Skylon. With Skylon, you just have to get to the closest ocean from your departure city. Note that most cities a VIP would visit are coastal. There would be a few minutes of sonic boom over the ocean to start the suborbital hop and then a few more minutes of boom at the end of the hop. Whereas supersonic jets require the boom the entire time they're supersonic because they stay in atmosphere. Atmospheric jets are also restricted by national borders, weather, and are subject to other aviation fees and regulations.

  • SpaceX Earth-to-Earth concept using Starship - this requires that a coastal platform be constructed near cities and it would still be very loud. Skylon would use existing international airports and only be loud for a few minutes over the ocean. Earth-to-Earth also has a last-mile problem in that it will take longer to get from the city to the coastal platform than the the suborbital hop itself. Skylon would be familiar to executives since they depart from and arrive at international airports, just like with a private jet. Skylon would also perform spaceplane operations entirely outside of any nation's airspace. In theory, Skylon could land anywhere a private jet could land without any special permission because it would be in jet-mode for the entirety of the time that it's in contact with ground controllers. From the perspective of the departure and destination airports, Skylon would be like any other private jet. Airports would just need Skylon facilities to refuel, inspect, and refurbish for the next flight but that's about it. This could even be achieved by landing a traditional support plane at the destination airport ahead of time and renting a hangar so it might not even require any special cooperation or partnerships with airports.

Probably the biggest issue with this idea would be operating cost compared to cost savings but I think it could be viable. Concorde wasn't exactly viable though and it was still something special. An executive Skylon would be a truly awe-inspiring achievement for Britain (much like Concorde) while also having the benefit of being the first step toward a fully fleshed out SSTO Skylon launch vehicle. Thoughts?

13:19 UTC



they are recruiting,so it means the project will advance faster:


14:40 UTC


Why does it seem that the Sabre Engine and Skylon development is taking so long.

Certain rocket development companies have managed to appear to make much more progress in the same amount of time than Reaction Engines.

Why does it seem to be taking so long for the development of this much needed engine?

Is it an investment problem? Is it because its new and sensitive design secret? Why does it appear to be taking so long?

11:54 UTC


everything new!

new logo,new design,new video,everything new: https://twitter.com/ReactionEngines/status/1235562433596534785

17:59 UTC


vote for skylon

it is a top rank for tech,vote for skylon! : https://www.businesscloud.co.uk/south-east-tech-50-vote

1 Comment
11:40 UTC


I’m writing a sci-fi novel and found the SABRE while researching SSTO. It’s so cool I had to include it. Now I’m a fan too, glad there’s subreddit to follow progress. 👍🏼

20:44 UTC

19:00 UTC


agreement to increase heat exchange to 2000C° instead of 1000C°

19:13 UTC


finally,they gave it!!

you can find in other sources but i can't find the original one. 2030s,that's awesome xd


17:01 UTC

18:37 UTC

22:54 UTC


New ESA collaboration for TSTO vehicle


Any thoughts on how far this is likely to go? States that a vehicle for launch from the Kourou French Guiana facility is what's being considered.

Also, with the recent push for re-usable cheap access in Europe per: https://www.retalt.eu/wp-content/uploads/2019/06/Press-Release-2019-06-14-a-1.png

Is it likely that the agreed upon French dominance in providing launch vehicles within Europe will side-line this* to an extent? I think I'm right in assuming France is to dominate launchers, Germany human spaceflight, and the UK satellites?

Edit: link added, missing word

18:15 UTC


skylon user manual

so here is all the details of skylon in general,but he doesn't exist since 2016,if anyone can find a more recent one thanks: https://web.archive.org/web/20160303231850/http://www.reactionengines.co.uk/tech_docs/SKYLON_Users_Manual_Rev_2.1.pdf

1 Comment
22:07 UTC


SABRE featured in Orbital Index, Issue #4

SABRE engine gets the green light. UK-based Reaction Engines’ air-breathing hybrid ramjet/rocket engine received investment from the ESA (€10m) and UKSA (£50m). The air-breathing phase of launch can take the proposed autonomous Skylon SSTO vehicle 22% of the way to orbital velocity, allowing the vehicle to carry 40% less oxidizer mass, thus increasing its relative payload capacity and making SSTO plausible. SABRE’score technology is its insane pre-cooler which is rated at over 1 GW/m3 of heat transfer. It can cool super hot compressed intake air that is moving at up to Mach 5.4 by ~1000° K in a twentieth of a second, allowing the engine to be built out of the lighter weight alloys critical to attaining orbit. By using helium in the pre-cooler, and then running it through a heat exchanger with incoming cryogenic hydrogen propellant, the engine avoids challenges with hydrogen embrittlement that would compromise its 50 km (!!) of 30 micron-walled tubing. While recent coverage touts SABRE as ‘new’, Reaction Engines was established in 1989 to continue work on a canceled British Aerospace Horizontal Take-Off and Landing vehicle that was conceived of in 1982 as a cheaper alternative to the Space Shuttle. Testing SABRE’s pre-cooler was funded by DARPA in 2017. They’ll be conducting high-temperature airflow tests by shooting exhaust from an F-4’s turbojet engine into the pre-cooler at 1000° C. Look for this testing to begin in the next month or so.

Read more at https://orbitalindex.com/archive/2019-03-19-archive-Issue-4/

19:59 UTC

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