Actively cooled rocket primed for easy re-entry

A German spacecraft featuring an angular design and active cooling of the heat shield looks set to launch in April. The Sharp Edged Flight Experiment (SHEFEX II) appears on the Andøya Rocket Range’s April rocket launch schedule (PDF). The SHEFEX website also mentions a Spring 2012 launch. SHEFEX I tested the basic concepts of …

[LaeMing]

Elite

That spaceship is strait out of Elite.

Which is way cool!

[CD001]

Re: Elite

Police Vipers (nice 'n' angular) ;)

[Amonynous]

"SHEFEX also has the distinction of being the only all-German spacecraft."

Apart from the Saturn V (and predecessors) you mean?

[Chris Miller]

"Our German scientists are better than your German scientists!"

[No, I will not fix your computer]

Re: German Scientists

I'm assuming this is a reference to the post war decision for the USA to "make up" a history for the Nazi Von Braun and his war crimes colleagues (project paperclip) so they could illegally avoid punishment and work for the US government instead? this compared to the Russians who didn't let any captured scientists work on their space program (and were all repatriated), and also had a Russian genius (Sergei Korolev) who not only reverse engineered the V2 (A4) but much improved it and then went on to develop completely new, original designs - all without any German input, he worked in Russia since the 30's (there's a really interesting story, and a true Russian hero).

"Our German scientists are better than your German scientists!"

This bit of propaganda, given out by the US was trying to excuse their actions (or paint Russia as bad), while Russia (bad in their own right, but for different reasons), didn't need German scientists (didn't use them on their space progam, and repatriated them), take Arthur Rudolph for example, who only left the US to avoid being prosecuted for war crimes (and Von Braun was to be investigated for the same had he not died of natural causes) - just google for "Dora Von Braun Arthur Rudolph" and make your own mind up.

[Yag]

Don't forget...

... the spacecrafts built during the mid 40s in a remote antartica based facility...

[oddie]

Re: Don't forget...

+1 for iron sky reference (or generic nazi arctic spaceship/flying saucer cultural reference)

[Robert E A Harvey]

My Auntie's house was flattened by a V2 when she was out at work.

[Flugal]

All German?

Part German, of course, but plenty of Merkins involved too, both in terms of design as well as build.

[Malc]

Elite

Anyone else reminded of the vector-graphic drawn ships in Elite?

[Nick Ryan]

Re: Elite

The Micro-G-Free Flyer REX certainly has a lot of similarities to the Elite ASP II.

[Anonymous Coward]

micro-gravity research... finally!

[Richard Boyce]

Flat panels with sharp edges

Is this mainly about making stealthy missiles?

[Sargs]

Re: Flat panels with sharp edges

Not sure that'd be the case. The ionised plasma sheath created during a re-entry will show up on radar quite nicely. During meteor showers, you can occasionally hear bursts of radio stations far over the horizon as their signals bounce off the plasma trails of the meteorites.

Besides, missile detection is based both on radar *and* IR sensors.

[Uncle Slacky]

Re: Flat panels with sharp edges

Possibly - it reminded me of the possible use of plasmas in boundary-layer control for stealth - the Russians were experimenting with this in the late 90s - see for example

http://www.spacedaily.com/news/future-00o.html

https://en.wikipedia.org/wiki/Plasma_stealth#Plasmas_on_aerodynamic_surfaces

http://defensetech.org/2006/03/30/stealths-radioactive-secret/

http://neqlab.com/text/228e.pdf

[Robert E A Harvey]

It does seem odd to be carrying more payload up just to pump out as a boundary layer for re-entry. Is it lighter than the ablative layer from the hull?

But sharp corners may be useful. Think of corona forming at points for electrically charged objects. With the right design a charged body could repel ionised gasses (maybe not very much?) I wonder if this could be combined with the electrospike ideas? We never heard any more about those.

[Anonymous John]

Well if it's ever used for a manned vehicle, you can use some of the air the crew have been breathing.

[Vic]

> you can use some of the air the crew have been breathing.

Errr - not really. I suspect they'll want to carry on breathing it during the descent...

Vic.

[Anonymous John]

I said "some of". As they are committed to landing when using it as cooling, there's no possible risk in using reserves of air. And they'd likely be wearing space-suits for the descent.

[Vic]

> there's no possible risk in using reserves of air

Except that they haven't got much in the way of "reserves".

Spacecraft are rebreathing systems; the air goes around and around. The CO2 is removed and the O2 replenished, but the bulk of the gas stays in the loop.

Vic.

[Graham Bartlett]

They do have some reserves though, else a leak would be game over. And when you're on your way down, by definition you don't need those reserves - either you come down in one piece and can pop the hatch for some fresh O2, or you come down in a lot more pieces and then you're pretty well ventilated anyway.

[Vic]

> They do have some reserves though

How much do you think there is?

> else a leak would be game over

Not so. You could make up for lost gas by using O2[1][2]. You wouldn't want to be pushing that out into a hot heatshield...

> by definition you don't need those reserves

I would absolutely disagree with that.

Compromising your breathing system redundancy during one of the most hazardous parts of the flight is an idea that should be filed under the general heading of "suicidal".

Vic.

[1] Assuming you could plug the leak in time, of course...

[2] This would, of course, raise the running ppO2[3], with a corresponding risk of pulmonary toxicity from the Lorrain Smith effect. But that's not going to be life-threatening within the timeframes we're talking about. Acute toxicity (Paul Bert effect) doesn't feature at these pressures.

[3] I'm assmuing normobaric pressure is restored. This wouldn't actually be necessary to sustain the crew - the human body functions perfectly well at just 0.16bar inspired ppO2 - but I don't know if a reduced internal pressure would have any significant effect on the craft structure.

[No, I will not fix your computer]

>>the human body functions perfectly well at just 0.16bar inspired ppO2

An O2 partial pressure of 0.16 (equivalent to 16% O2 at 1 bar) would be survivable for an astronaut or other athlete but it's definitely going to cause a problem with coordination and physical exertion for a prolonged period (this level would be dangerous for someone with underlying health issues), I've tested out the O2 usage on long haul flights and even droppng below 20% can increase the number of people experiencing air sickness.

Out of interest, low pressure, high O2 was dabbled with early on in the US space program, but the risk of fire was found to be too great, in fact that's why Apollo 1 caught fire (the Russians always used 1 bar air), although it sounds simpler to use air, in fact it's more complex than low pressue O2.

[Vic]

> survivable for an astronaut or other athlete

It's more than "survivable"; it's fine. 0.16bar is plenty. 0.12 is survivable - but you *will* be symptomatic at that level.

> it's definitely going to cause a problem with coordination

It's definitely not going to.

> (this level would be dangerous for someone with underlying health issues

Only if such people have a problem getting inspired O2 into the bloodstream - someone with a serious breathing disorder, for example. Such people do not make it into space...

> I've tested out the O2 usage on long haul flights

And what is the pressure on those flights?

Inspired FO2 is related to inspired ppO2 by Pamb. We are sensirive to ppO2, not FO2. A 767 at altitude has Pamb < 0.8bar, so if you did breathe 20%O2 (and I'd love to know how you conducted these experiments), your inspired ppO2 would be less than 0.16, and you would expoect some symptoms of hypoxia.

Vic.

[John Smith 19]

@Robert E A Harvey

"It does seem odd to be carrying more payload up just to pump out as a boundary layer for re-entry. Is it lighter than the ablative layer from the hull?"

Depends.

Key benefit is total *reusability*. Refill the tank and in *principle* you're ready to go again.

[Tom 7]

Thunderbirds are go

A technique used in boating to reduce friction used in rockets so we're nearly there.

[Dom 3]

Explain?

"Higher-temperature re-entries mean spacecraft need not have wings to glide the final kilometres to earth’s surface and can instead use parachutes."

Another badly-written press release quoted more-or-less verbatim by El Reg?

[Graham Bartlett]

Re: Explain?

Doesn't make sense to me either. All re-entry systems apart from the space shuttle have used parachutes for the final descent to ground.

[Gordon 10]

Re: Explain?

Technically even the Shuttle used parachutes in its descent. Albeit to brake horizontal velocity rather than vertical.

/pedant.

[Kevin Turvey]

Re: Explain?

Technically as the Shuttle had landed and was merely trundling along the runway, I would have thought it is no longer descending / in descent.

[Anonymous Coward]

"...Sharp Edged Flight Experiment (SHEFEX II)..."

Bit of an insipidly disappointing name from the German lads, there. "Shefex" sounds like something you'd clean cupboards with. I'd expect better from the people who put the 'hard' into hardware, with names like Vergeltungswaffe and Sturzkampfflugzeug.

Any German speakers out there able to come up with a tougher sounding monicker for this latest Teutonic gadgetry?

[Gordon 10]

V3

[Michael H.F. Wilkinson]

Should this craft not be manned by Kryten?

Looks like the perfect pilot for it

[MahFL22]

Where exactly in Germany is this thing supposed to land ?

[Scott Wheeler]

> SHEFEX also has the distinction of being the only all-German spacecraft."

The boundary of space is usually set at 100km. The V2 rocket could exceed that in the 40's, and although it did not have the advantage of a re-usable design, it did not require a specially prepared landing site.

[John Smith 19]

This *could* be huge for Europe.

Here's why.

To lower the cost of return from Earth orbit you want to land it in your back yard. Europe is densely populated. Perhaps surprisingly ballistic capsules making lifting re-entries can be *very* accurate.

They are called ICBM warheads.

Unfortunately they only work because they use *substantial* amounts of ablatives to burn off and carry the heat away (and they are never going to land).

Outside Ablatives the *only* other candidate is Reinforced Carbon Carbon, which Germany is *very* good at (they were doing the nose cone for the cancelled X38 research vehicle).

But RCC is normally moulded in 1 piece. It's a PITA to mfg and somewhat fragile. essentially it's designed to fit *one* vehicle and nothing else. As the shape expands/contracts the Silicate protective coating has a tendency to crack.

The German development is to make "uncommitted" *sheets* of RCC, cut it into tiles and fit them to a shape (conceptually it's *exactly* like a computer graphics simulation of a 3d object by choosing the right polygons) which despite it's *very* angular looking nature has actually very good L/D characteristics, giving (potentially) good cross range without wings. It's also *lots* easier to grow the oxidation protection coats on 2d shapes (Carbon + O2 ->CO2, or "designer coal" as people have called it without the coat).

Want it bigger? Add more rings of polygons.

Want wings. Add new sections as appropriate.

But RCC is *heavy* relative to Shuttle tiles (that's 1 reason why it' s use was limited to *very* high temperature areas on the Shuttle) so going with active cooling lets them go with thinner tiles.

The Germans have pursued re-usable space transporters since the 1960's (Dornier & Messerschmidt were active) but heat was *always* the issue and RCC does curves *badly*

Frankfurt to *anywhere* within 90 mins (you have to go the long way round for *close* destinations. To the other side of the world it's nearer 45). anyone?

For some the idea underlying Eugen Sangers Silverbird have never been forgotten.

[Anonymous Coward]

Superconductor shields?

Wasn't there a prototype based on plasma shielding using a superconducting dipole that never got tested due to budget cuts?

AC/DC 6EQUJ5

[Shady]

That's a lot of effort...

...to go to lay a couple of beach towels on the moon.

[Paul Hovnanian]

Tom Lehrer lyrics stuck in my head

'Once the rockets are up,

who cares where they come down?

That's not my department',

says Wernher von Braun.

[sniperpaddy]

German Gliders ??

Bully boy economic policy and now gliders?

Surely this is history repeating itself ??? ;)