A real SSTO?

[Beeburgers]

Yup, that's a bit of concept art for the UK's Skylon space plane. If you're like me, the first thing you're probably asking yourself is: where are the air intakes?! The science for the pair of SABRE engines strapped to either side seems to defy Kerbal logic, mainly because it has a problem with overheating when it's going at Mach 5 at 28 km above the earth. Apparently air gets kind of hot when you're brushing past it at five thousand plus km per hour... who knew?

And at those speeds it's really more important to cool the air down enough for it to be used than it is to get more air into the hybrid rocket/jet engine. Basically there are a series of heat sinks sitting next to some pipes all full of liquid helium. The air passing into the engine goes from somewhere around "OW! Damn it that's hot!" to "OW damn it that's cold!" (or 2,000 degrees Fahrenheit to about minus 238 for those who don't speak Angry-Man-anese) Once the air is cooled, it gets sucked into a turbo compressor, mixed with liquid hydrogen and then set on fire... And by that I mean it acts like a regular rocket.

Once the Skylon gets to it's max air breathing altitude of some 28,000 meters above the earth it shuts the air intake and switches to a reserve of liquid oxygen kept on the spacecraft. This supped up hybrid engine, the SABRE, is one of those ground breaking type things that could actually make traveling to the other side of the planet a four hour trip, or cut the cost of putting a satellite into low orbit by a factor of ten. Now that's all well and good, but I have only one thing that I can think of after reading these articles: "I want one!"

Whatcha think?

LINKS!

SABRE: http://en.wikipedia.org/wiki/SABRE_(rocket_engine)

Skylon: http://en.wikipedia.org/wiki/Skylon_(spacecraft)

What the SABRE looks like inside and out:

(I got most of this info from the great and mighty wiki, and the rest from Popular Science... thought I should mention that)

[mythbusters844]

Yep, saw this on Popular Science. Proved interesting for me.

[Mr Shifty]

This supped up hybrid engine, the SABRE, is one of those ground breaking type things that could actually make traveling to the other side of the planet a four hour trip,

Very cool. I had heard about SABRE and the Skylon project, but not looked at it in any detail before. Regarding this four hour trip: you should check out this challenge thread on the Orbiter forums. They're using a near-future-"realistic" SSTO with scramjet engines to do speed runs from Kennedy Space Center to Ascension Island off the coast of Africa, which is a total distance of 8,200 km. The best times are around 17 minutes from wheels up to full stop, which is incredible if you think about it because it requires an average speed of 8 km/s, which is orbital speed. In fact, the best pilots are getting up to 15 km/s (which is greater than escape velocity for the Earth at the altitudes they're flying) and using the attitude of the craft in the wispy upper atmosphere to keep their trajectory curved around the Earth. The XR2 (the spacecraft being used) accurately models the effect of G forces and heating and dynamic pressure, so these are survivable trajectories. And it has a default Isp of about 4000s, which is only about twice what the wikipedia says may be possible with SABRE engines. Imagine getting from LA to London (about 8700 km) in less time than it takes for your current morning commute.

[NGTOne]

I've actually got really high hopes for the Skylon project - they're currently the only ones, as far as I'm aware, with a halfway feasible plan for a reusable SSTO. And they completed a technology demo not long back for the engine precooler - the most important single piece of new technology the project requires.

The problem is, they're relying on government funding, which basically doesn't exist for new-technology projects. The estimated cost of the project is a couple of billion before they have a flyable unit, but they don't even have a tenth of that. Since this is a European project, I wonder if Airbus would be willing to back it...

[Nibb31]

We've been discussing Skylon for ages. Please don't start new threads when one already exists:

http://forum.kerbalspaceprogram.com/showthread.php/34403-Do-you-think-Skylon-will-be-our-first-completed-SSTO

Edited August 28, 2013 by Nibb31