Two-Stage-to-Orbit Spaceplane Program Shelved

MadMorf writes "According to this article in Aviation Week, for nearly twenty years the USAF and "a team of aerospace contractors" has designed, built and tested a two-stage-to-orbit spaceplane, which could be used for "reconnaissance, satellite-insertion and, possibly, weapons delivery". Now this highly classified project may have been shelved for budgetary reasons."

Comments

space plane

[mytrip]

This is a shame. I remember talk of this when I was in aerospace in the late 90s. I am of the opinion that most of the progress to be made on this type of thing is going to be done in the private sector and therefore the technology will be available to our enemies as well.

History repeats!

[OzPeter]

The USAF DynaSoar concept was considered and canned by 1963. So what else is new?

100k "drones"?

[mnemonic_]

Could you please name a single "drone" with a 100k ft. cruising altitude? Or to be more blunt, did you just make that up? I've researched UAV technology pretty extensively and haven't heard of any that fly that high. NASA/Scaled's Proteus and the RQ-4 Global Hawk have only reached about 65k, while the SR-71. I believe the D-21 could reach 100k from its launch platform (SR-71 at 75k), but that died out in the 1960s.

Re:100k "drones"?

[Isca]

Nothing that is offically anounced, but it's been done already, with just some tweaking to make it better.

First up, A solar powered UAV that was tested 3 years ago to reach near 100k. Now, I'll grant that it wasn't a production model, but who's to say with a bit of black technology and a much larger budget this hasn't been duplicated?

There's also multiple models of blimp based technology, such as this or this. Now, granted, the blimps would be a bit harder to hide from, but then again, if it's there 24/7 for months, you can't exactly time when you move targets, like you can with sats.

Now, I am talking out of my ass here, but my guess is that IF they had this technology working, and in production, then that would make a strong case to stop an expensive manned vehicle that may have been designed to do essentially the same thing. Especially if one of those said drones were missle delivered, as the conncept plans from years ago indicated.

AvWeek is a reliable source, take this to the bank

[Thagg]

In recent years, Aviation Week has become somewhat more conservative about its coverage -- it's a little disappointing in some ways, as now they are often the last place to publish something -- but they are very rarely mistaken about a scoop like this.

They often publish photographs of planes, too, and leave the interpretation up to the reader. For example, they published the first photos of Rutan's White Knight, the carrier for SpaceshipOne. The White Knight/SpaceshipOne system flies a profile very similar to the one described by this current article, although with much lower performance.

Anyway, AvWeek published the White Knight photos with no description of the plane's mission, but any informed reader would immediately recognize it as a spaceplane first stage. Once Rutan announced the program, they covered it completely, but until they knew for sure they didn't say anything. For them to describe this Blackstar system in this explicit detail, I am certain that all their ducks are in a row -- and barcoded.

Thad Beier

Re:Wishful thinking

[AKAImBatman]

Here's the math. Plug in an Isp of about 400 for LHOx engines, a desired velocity of about 8.3 km/s, and a starting velocity of about 0.92 km/s.

Taking the final velocity minus the starting velocity, we get a required Delta V of 7.38 km/s.
Converting from Isp to exhaust velocity, we get (9.81 m/s * 400) = 3.924 km/s.

Thus our equation looks like:

m1 = m0 * 2.718^(-7.38 / 3.924)

"m0" is the starting mass of your rocket, m1 is how much mass you'll have left after you achieve the required Delta V. So, if we take a 20 tonne starting craft (for example) and plug it into the equation, we get:

m1 = 20,000 kg * 2.718^(-7.38 / 3.924)
m1 = 3,050 kg

To get the ratio of fuel to craft, we compute 1-(3,050/20,000) to come up with a craft that is about 85% fuel, leaving about 15% as craft mass. Considering that the Space Shuttle only gets about 6.75% of its mass to orbit, 15% is pretty darn good.

To compute the other way (how much fuel mass is needed for a given final mass), you can compute the following:

m0 = m1 * 2.718^(7.38 / 3.924)

If we assume a larger number than before (say, 20,000 kg of ship+cargo to orbit), we come up with the following figures:

m0 = 20,000 kg * 2.718^(7.38 / 3.924)
m0 = 131,140 kg

Again, we see the same ratio (1 - (20,000 / 131,140) = ~85%), but the sizes have increased. The question is, could the Valkyrie (XB-70) carry 131,140 kg of spacecraft?

Well, according to the specs I have, it had an empty weight of 93,000 kg, and a maximum takeoff weight of 250,000 kg. Maximum loaded capacity was 242,500 kg, so you can assume that the 8,000 kg difference is probably fuel expended to get off the ground. Doing some simple math (242,500 kg - 93,000 kg) we come to a final cargo capacity of 149,500 kg. Taking away the weight of our craft (149,500 kg - 131,140 kg) we find that the Valkyrie would have 18,360 kgs left over for fuel and other weight. That shaves it pretty close, but it's doable.

If you assume that the Air Force has increased her Thrust to Weight ratio with some of the more powerful jet engines that have been designed since the 1960's, the margins actually look pretty darn good.

Does that answer your question?