A better example than the X-15 or SpaceShipOne might be the Pegasus, which is launched the same way but does reach orbit (but can’t carry humans).
No problem! One thought that has always interested me is how would space travel developed if there hadn’t been the pressure to match the USSR - no Man in Space Soonest and Project Mercury followed by the Moon within the decade but a sensible progression from the X15 to reusable orbital craft. Not sure if there is such a route or if you end up back with the Shuttle.
Maybe **Stranger **could comment?
The best thermal material for this has existed for a long time (Starlite). Due to various vagaries trying to get it into production it isn’t being used but frankly this stuff seems magical and the perfect answer for thermal protection.
Well, it’s magical because it’s made out of uni-directional Unicorn horn…
More discussion here.
I see nothing there to suggest the claim is false.
It may not live in the core of a nuclear explosion and be subject to shock damage but I think repeated tests by Britain’s Atomic Weapons Establishment lends it a distinct air of credibility to its claims. Can you name another material that will survive 10,000 C temperature hits…repeatedly? Aerogel maybe but I doubt aerogel is suitable to cover a Space Shuttle.
As mentioned in the other thread it seems this guy’s eccentricity is what is preventing it from being marketed.
Orbital Sciences does this with their commercial Pegasus family of launch vehicles, which are launched from beneath an L-1011. The Pegasus air launch vehicle can be compared directly with a ground launch vehicle, as the OSC Taurus is a Pegasus stack on top of the 92 inch Castor 120 “Stage 0”. For instance, the Taurus 3210 launching from Kwajalein Atoll on the Reagan Test Site can achieve a 200 nmi circular orbit at an 11° inclination with a >1200 kg payload (and larger fairing), while the air launched Pegasus XL launched from RTS can only deliver a payload of about 430 kg to the same orbit. Part of the difference is the level of thrust available from the Castor 120, but the efficiencies gained by air launch from a relatively slow moving aircraft are just not that great. The real advantages are the ability to locate your point of launch to the most efficient azimuth (within the constraints of the range and ground hazards) and increased launch availability (you don’t have to worry about the impact of ground winds and weather conditions on launch constraints, as well as not having to cope with things like ground facility conflicts, environmental impacts (every government-owned space launch range in the continental United States is located in or near a nature preserve or controlled habitat) or protesters.
I think part of the appeal of plane-type space launch vehicle concepts is that they seem familiar to what we already know and use on a daily basis. However, the environments, conditions, and functions of space launch vehicles and spacecraft–which spend most of their time at very high Mach conditions or outside of the atmosphere–is nothing like airplanes, which spend all of their time in a substantial atmosphere which provides both oxidizer and a fluid medium to develop lift, and the attempt to marry the two functions in a single vehicle result in pretty severe compromises. The anticipated reusability, reliability, and short turnaround time of the STS/Orbiter (shuttle) turned out to be hopelessly optimistic, as were estimates of the cost savings by consolidating all launches into the one vehicle, even compared to the fixed costs of purely expendable vehicles.
I would tend to disagree that the development of a workable SSTO vehicle is actually all that distant, at least in terms of the technical feasibility. There are several vehicles in the former US inventory that are practically SSTOs, albeit with a negligible payload, indicating that developing an SSTO vehicle with a practical payload capability is really a matter of increasing performance marginally rather than requiring revolutionary new propulsion technology. The biggest hurdle to an SSTO is an engine that provides good performance at a range from sea level to exoatmospheric. On multistage vehicles nozzles on stages are optimized for the range in which they operate, so that nozzles for lower stages are smaller and lighter than nozzles for upper stage motors/engines which attempt to capture the additional momentum from plume expansion.
For an SSTO, you would like a nozzle that can provide variable performance to provide optimal thrust at different altitudes without adding a lot of weight like an extendable nozzle. Nozzle designs that do this (plug and aerospike nozzles) do exist, and while not at a production-ready level of technical maturity have been demonstrates in full scale static fire tests. An aerospike version of the RL-10 in a Saturn S-IVB-based vehicle should provide adequate performance to achieve low Earth orbit with a reasonable payload, even given the fairly heavy metallic structure. A vehicle like the Delta Clipper concept making substantial use of lightweight composite structures for tankage and main structure could conceivably deliver a payload to orbit with just minor improvements of conventional engines, and developing aerospike or plug nozzle engines that can manage even a small percentage in total impulse improvement would allow you to fly even a very large vehicle like the Chrysler SERV to orbit with a heavy payload or separable personnel shuttle, and even recover and reuse the launch vehicle. (As with the shuttle, I question the turnaround time–aerospike engines would likely have to be replaces or refurbished between flights due to erosion of the nozzle spire–but even given that there is still more of the vehicle that is reusable than the STS, and the complexity of thermal protection systems with this concept is greatly reduced compared to a spaceplane design.
We could be ten to fifteen years away from a working SSTO with the same budget that was used to build a Shuttle-based expendable launch system, with comparable payload capability, lower costs and (likely) higher reliabilities. But not with spaceplane concepts, which still press the limit in thermal protection technology.
Stranger
I question that without the Cold War strategic race that we would have had heavy lift capability to support the space race, and without a competition to put people in orbit and to the Moon, I doubt there would have been the impetus to develop manned space launch capability, especially given the massive cost of such a program. The X-15, despite being a rocket-powered vehicle, is really an aircraft, and as a general concept lacks many features required for an orbital vehicle, nor do I think it could evolve into an orbit-capable spacecraft.
Although I’ve heard snippets about this technomagical “StarLite” material for years, I have yet to see a documented test of the material despite claims, and I see several indications that the asserted property and testing of the material is false, including that it was tested by AWE in a nuclear explosion-like environment or “Ward refused even to allow the formula to be written down; only he and a couple of family members knew it, and it was kept only in their heads,” as if it were a recipe for cheesecake. As for the use in a spacecraft thermal protection application, we’d need to know more than just what its combustion or degradation temperature (presumably what is meant by “10,000 °C”, such as thermal and mechanical properties (thermal conductivity, emissivity, specific heat capacity, density, tensile and shear strength, fracture toughness, surface finish, corrosion and chemical reactivity, et cetera). If this material is an aerogel-like substance, it may provide good thermal insulation but lack the mechanical properties to withstand flight environments or thermal mass to absorb the heat flux incurred during reentry. An unprotected human could withstand an environment in which the ambient temperature of 10,000 °C if the heat flux is low enough (though you’d probably want an air supply).
Stranger