Skylon: They Do it with Smoke and Mirrors?

The proposed Skylon space transport. Looks a little SR-71 derivative, doesn’t it? Image from

Every now and then I’ve heard of this Skylon space transport.  It sounds very interesting and I honestly hope technology like it does come to fruition.  But here’s the thing:  Skylon-related research has apparently been going on for over thirty years.  According to the wiki, which might contain some inaccuracies, the idea of horizontal take-off and landing with a single stage reusable spacecraft was starting to be explored by the United Kingdom government as early as 1982.  Skylon has cost UK taxpayers about $12 billion just in development (at least according to the wiki).  What has the result been thus far?

This is my question, because Skylon sounds very neat.  It seems like it would really be revolutionary if the technology becomes a reality.  But the catch is that I haven’t seen signs of Skylon approaching reality at all.  There are a few BBC videos of engine tests, but I’m not a engine specialist, and they could just be showing off a jet engine.  What I am seeing is a lot of “dog and pony” animations only of what Skylon could look like and what Skylon could do.  Maybe the BBC is part of the cheering section?

It looks like the Skylon animation budget is at least getting its money’s worth.  But the animations seem to be the only product from the Skylon program, which raises red flags to me.

Why?  Well, let’s look at a few other rocket programs, also aiming to be reusable and inexpensive.  SpaceX has been making a lot of noise and news about their Falcon 9 rocket.  Not only has the Falcon 9 been successful for the relatively new rocket company, but SpaceX have been developing many different technologies to make their rocket approach reusability (you can read up on some of those things, here).

While SpaceX is testing basically vertically launched and vertically landed rockets, Virgin Galactic seems to be edging more into the horizontally launched and landed rocket territory of the Skylon.  They’ve been test launching their rocket for a few years now, and SpaceShip one, the first of this type of Virgin Galactic rocket, first flew into space over 10 years ago, in June 2004.  There is no similar evidence of progress from Reaction Engines, Limited, which has been working on Skylon for nearly 25 years.

Even more distressing is the fact that Skylon is supposed to make access to space cheaper, which this CNN post states will be about $94 million per flight.  That price is cheaper than Arianespace and ULA rocket flights–however, SpaceX already advertises around a $6o million per rocket flight basic cost–without reusability thrown in.  And Musk has said he believes once his rockets attain reusability, the prices will suddenly be in the hundreds of thousands of dollars range, not the ridiculous millions needed currently.

Virgin Galactic is selling seats for $250,000 a pop.  This means it will also be able to sell the option to launch payloads cheaply–definitely cheaper than $94 million.  Just to be more international, even India is managing to get payloads into geosynchronous orbit for about $70 million (and their system isn’t designed to be reusable).

Have either SpaceX or Virgin Galactic actually used their reusable rockets for any commercial launches yet?  No–but they are showing more than animations and engine tests.  They are showing actual rockets in flight with video of what their rockets are doing during testing.  Shouldn’t Skylon, after all of these years, be able to do the same thing?  And for cheaper than $94 million?  If that price is their goal, then isn’t that already heading for failure, because it just won’t be able to compete with cheaper possible reusable options?

Anyway, until they can actually fly a Skylon, the program will all be just smoke and mirrors to me.  And too expensive for my tastes.

Update:  Oh dear!  It seems there are true fans out there of this particular technology, just like with SpaceX.  Some care enough to clarify a few things about REL, Skylon, etc.and point out the initial pricing launch, which comes from ESA via CNN, is too high.  Read those comments if you wish to learn more.


6 thoughts on “Skylon: They Do it with Smoke and Mirrors?

    1. Hi Dan!
      At risk of feeding the trolls here, but maybe my other readers would like to know how I conduct some of my own analysis and research. First, your comment was such a generic critique, it almost looked like most of the spam the WordPress filters catch. So work on that, otherwise other bloggers might just list your comments as spam.

      However, thanks for the input and glad you cared enough about my research techniques to chime in. Obviously, there’s more to writing this post than Wikipedia reading–there’s the Reaction Engines, Ltd. site as well, plus the CNN post that brought my attention, yet again, to a non-existent spacecraft. I use those as a baseline for trying to find other information on the web using different search engines, as that’s the only tool I can use to find my sources. Looking on any of these and other sites yielded no pictures or videos of a “real” Skylon spacecraft, only simulations, which is my point. Another reader has pointed out one of the press releases of RL, LTD, here: Which underscores my other point of the UK possibly throwing away good money after bad. If you disagree with the tone of this post and my opinion, which this post definitely reflects, then great! I’m happy when someone decides to respond and thank you for the opportunity to explain a few things in the process.



  1. Reaction Engines Ltd was formed in 1989 to pursue Skylon after the cancellation of the Bae HOTOL project by some of the most experienced British engineers in the field. As of the beginning of 2014 the project has cost around $80 million, 85% of which was privately funded.
    Skylon as a design and business case has been extensively independently vetted by ESA and London Economics both in the most recent SELO study and in the previous Skylon technical assesment both of which the Skylon passed with flying colours, while it is currently undergoing assesment by the USAF.
    To date REL has manufactured and tested the key precooler technology as well as, micro channel heat exhangers, advanced E/D nozzle designs, silicon carbon reinforced titanium truss struts, silicon carbide reinforced glass ceramic TPS panels, contra rotating turbines and low NOX combustors. The DLR has conducted full re-entry CFD on the Skylon vehicle as well as tested LOX and air cooling on a rocket chamber for REL. The vehicle shape has also been tested in subsonic and hypersonic wind and shock tunnels.
    As of this year REL has entered phase 3 of their development program, in 4 years they intend to have a functioning prototype engine as well an overall vehicle definition of Skylon and a production consortium to build it, phase 3 is fully funded to the tune of $360 million and by the end of the year REL will be a company of 200 people.
    The S-ELO report hasn’t been published but it asked a very specific question, would Skylon be capable of fulfilling the Ariane 6 role for ESA and the answer was yes and that it would be cheaper than asked for and competitive with Falcon, beyond that the details of the study aren’t known but Ariane 6 is meant to fly 20 times a year so that is probably the Skylon flight rate. The business model of REL is the airline model, to sell Skylons to operators and allow them to find their own business models. The actual launch cost of a Skylon is projected by REL to be around $5 million so the launch price is dependant on the other operator costs, spaceport costs, insurance, maintainance, amortised unit costs, etc. Clearly as flight rates climb launch price can fall dramatically.
    Comparing Skylon to Falcon reusable, neither exist but taking the word of each company Falcon Heavy-R has approximately the same performance as Skylon at twice the price while Falcon 9-R has half the performance at the same price.
    All this information is freely available, if you wish to seriously research Skylon the nasaspaceflight Skylon threads have been aggregating all of it for years now as has Also there are frequent REL lectures, many of which can be found on youtube and REL has presented many papers on their activities to the IAC and BIS.

    Liked by 1 person

  2. Thank you Lliam, for the information. It’s good that there are many papers and studies out there. I’ve been presented, in another forum, other launch price numbers for the launch which are different from yours and different from CNN’s post. Obviously, I used CNN’s number, which they say comes from the ESA, with possible downward pricing depending on the number of “launches” Skylon might do.
    There’s a lot written about REL’s and Bond’s intent. I’m beginning to think, though, that someone from those forums you mentioned should update the Wikipedia Skylon entry to program cost, if what you say is true. That entry says the program, right up to 2004, was $12 billion. I understand there can be inaccuracies with these entries.
    What I will do is add a blurb at the bottom of this post referencing thes conversations for others to consider.



  3. The total currently projected program cost for developing Skylon plus the Skylon Upper Stage is $14.3 blliion dollars, but obviously it hasn’t been spent yet or there would be Skylon’s overhead, that’s all the wikipedia article is referring to.
    The launch price of Skylon is a complex question as REL is employing a totally different business model to all existing launch providers who all build the vehicles they launch where as REL (and consortium) will merely sell them to an operator or leasing company and then sell maintenance contracts along side them.
    Skylon is design to have a low operational cost with a two day turn around and at least 200 reuses, and as I said a launch cost of $5 million dollars but the launch price for a customer depends on the business model of the operator, the fixed costs of spaceport fees etc plus flight rate dependant costs like insurance and ultimately what REL charges for a Sklyon.
    Finally there’s the use the Skylon is being put to, filling an orbital depot with low value fuel might come at a much cheaper price than puting an operationally responsive surveillance satellite over a new warzone by Tuesday, both because the former has lower insurance costs and because the latter is something only Skylon could do.
    Ultimately the price of a Skylon flight is a large spreadsheet with costs on one side, flight rate on the other, and a lot of subjective guessing about how many operators there might be and how they might go about competing for market share and generally how much flight rates can be expanded.
    The ESA S-ELO study is just a study to see if it meets their criteria for Ariane 6 with their flight rate assumption and their operator assumptions.
    A different operator might use different numbers and sell for a different price.

    Liked by 1 person

  4. It probably helps to remember that, while SpaceX have been trying to reuse stuff since Falcon I; SpaceX in fact haven’t successfully landed any real vehicle yet,

    Even when (presumably) SpaceX succeed, will they, ever, be able to do it reliably, ten times, with the same vehicle? Right now they’re literally beyond the bleeding edge, every single time they try it, they crash.

    It’s also notable that SpaceX is sacrificing quite a lot of payload to do the reusability, which raises the cost/kg.

    The Skylon design has the very much larger margins; if they hit problems, they’re much more likely to overcome then; SpaceX are having to shave everything to the absolute bone to reach orbit at all, and that’s got a lot to do with the repeated crashes.


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