GIGANTIC Aviation Week story, Pentagon has been flying 2-stage orbital spaceplane throughout 1990s&# Options

[Guest_BruceMoomaw_*]

It may even have been manned:
http://www.aviationnow.com/avnow/news/chan...ws/030606p1.xml

My God, what a story -- if it's even partially true. And, judging from this article, they are absolutely certain they have proof (along with proof that the thing, although it works, has recently been mothballed as not
cost-effective).

It's important to keep in mind, though, that this thing is NOT a workable prototype of the originally planned 2-stage winged Space Shuttle. The second stage -- the spaceplane that actually achieved orbit -- was relatively small and probably very inefficient as a cargo carrier; its advantage lay in allowing the US to get a military reconaissance (or weapons) satellite into orbit surreptitiously, with no advance warning of the launch going to other countries. Even at that, as I say, AW reports that the thing has been recently canned as not worth its (doubtless huge) black-budget expense.

[tty]

Here it is Jeff Bell who is off speculating in the wild blue yonder for a change.

It is true that grids are used to prevent radar seeing the compressor front in stealthy aircraft. It is also true that they are not used in the engine exhaust for the good reason that they would become red-hot and make a wonderful target for an IR seeker. There are a number of other techniques for shielding the turbine face from radar.

There is no vectored-thrust version of the Sparrow or AMRAAM. They would in any case be completely (Sparrow) or almost completely (AMRAAM) useless for a stealth design aircraft. Sparrow is a semi-active radar homer and requires a radar to illuminate the target. Not good for a stealth aircraft.
AMRAAM is an active radar homer and so theoretically could be used provided you know the range and direction to the target. So I suppose it could be usable if the stealthy aircraft had an IRST system combined with a laser rangefinder.

The AIM-9X Sidewinder II has a vectored-thrust control system, so I imagine this is the missile JB is thinking of. Moreover it is an IR seeker with excellent off-boresight capability and so would be the natural choice for a self-defence missile.

However it will take more than a little work to build a missile that can be launched backwards. There have been a number of efforts last by Vympel with their R-73M, but nobody has succeded yet. Building a control system that can cope with the airstream changing from high speed in one direction to high speed other direction with an interval of essentially zero speed (and zero rudder effectiveness) within a few seconds while keeping the missile stable enough not to lose lock on the target and maintaining altitude when there is no aerodynamic lift will take some doing. The fact that the missile will be within the slipstream of the aircraft and flying backwards through it's own rocket exhaust doesn't exactly simplify matters either.

If you want another alternative explanation for those "white tubes", I would suggest chaff/flare dispensers. Much simpler, and workable.

tty

[Bob Shaw]

If you want another alternative explanation for those "white tubes", I would suggest chaff/flare dispensers. Much simpler, and workable.

tty

I was thinking of that myself, you took the words out of my mouth!

As for the 'grids' - well, they're in common use on ex-Soviet missiles as aerodynamic surfaces which pop out after launch. Most memorably, though, are the self-same items on the Soyuz manned launcher - the grey squares on the spacecraft shroud are actually pop out stabilisers.

So both white tubes and grids have a straightforward explanation, particularly if it was a half-glimpsed hardly-believed view which the (pretty reliable sounding) witness had.

It all adds up to something other than a modernised X-20, though! I don't think that AW&ST have covered themselves in glory on this one (although their taste in cover pictures is, as we all know, impeccable).

Bob Shaw