China is launching a reusable space plane in2020

a reply to: TheHans

Hypersonics is way harder than you're thinking. Material science takes time and we didn't have it back then.

We did have an air launch for rockets though:

en.wikipedia.org...(aircraft)

It wasn't exotic and wasn't a TSTO. Neither is Cosmic Girl. Nor will Stratolaunch be.

a reply to: TheHans

Ever watch the M-21 release accident video? Things like that tend to happen when trying to release at high speeds.

I have seen that. The A-12/SR-71 wasn’t purposely built as a launcher - it was a retrofit. I think dropping the vehicle might be a better way. Boeing seemed to think they figured it out in 1989:

robotpig.net...

Aviation Week’s version, for what it’s worth, also had the spaceplane being dropped:

deepbluehorizon.blogspot.com...

The Chinese seem to think its viable. Although, I’m. Little suprised by how close the vertical fins are spaced on their concept.

I guess if the Chinese manage to pull it off, we’ll know supersonic TSTO is a viable concept. Whether the US pulled it off 20 years ago, who knows... There were quite a few sightings of something large and loud from that time frame (including my own) as well as mystery sonic booms, and rocket-like rumblings over the desert southwest (Circumstancial but interesting).

I’m struck by the similarities in the Chinese video and the Blackstar and RASCAL rumors. I guess form follows function.

stargazer2006.online.fr...

Here’s an intersting tidpit from a retired aerospace engineer in response to whether RASCAL was feasible:

“Quite feasible for “"second stage” that was light enough for the F-106 to get to altitude and speed. It was only going to be the “"first stage” of the launch. In other words, the F-106 would have mounted the launch vehicle on the centerline or under the wing. It would take off, perform a zoom climb to altitude and launch the missile carrying the satellite. The basic launch events exactly parallels the process used by the Pegasus launch system, except that Pegasus uses an L-1011 as the launch platform.

Pegasus (rocket) - Wikipedia

So the basic answer to your question is a resounding YES it is feasible.

In the mid-80s when I worked for Martin Marietta we investigated the same concept but for a larger payload and booster than an F-106 could possibly carry. Our concept was to use a B-58 Hustler as the launch vehicle. It had the advantage if a very heavy duty centerline pylon, long spindly landing gear, and four J79 afterburning engines. That could get it and it's missile payload to a high supersonic speed at altitude. Unfortunately when we looked deeper into developing a proof of concept, we found that all B-58s had either been relegated to pedestals at USAF facilities or converted into scrap metal! The big advantage of the B-58 was the weight of payload (booster and satellite) that could be delivered to the highest possible altitude and highest possible airspeed at release.”

www.quora.com...

a reply to: TheHans
whiteworld study, 1992:
ntrs.nasa.gov...

There is still a big difference betweenn a disposable rocket and a (manned) return vehicle as an upper stage.

originally posted by: TheHans

Funny there are two stories active today on ATS - the Cosmic Girl thread and this. I may have been fairly average in calculus, but if a 747 can serve as an effective first stage for a TSTO, then how much better (more energy) would a large airframe able to travel at Mach 2-4 at 80-90K feet be for a platform?

It's really not all that great when you do the math. The altitude doesn't factor very much. The biggest requirement is for velocity. Mach one at 80,000' is under 300 m/s. Orbital velocity for LEO is ~7,500 m/s. Even if we generously say you have already paid for and developed a Mach 4 platform capable of carrying your second stage and call Mach 4 1200 m/s (@ ~85,000' altitude) it only represents ~16% of the velocity needed for LEO. Mach 2 is obviously half that.

Now figure what the operational costs are for your supersonic first stage platform, factor the additional complexity and risk at launch, etc , and it's pretty clear why this remains an expensive niche capability.