USAF to test concept RLV airframe

Over the next four years an X-vehicle airframe design for a future reusable launcher will be ground tested under the US Air Force Research Laboratory's $70 million Fully Reusable Access to Space Technology (FAST) programme.

The airframe testing is to be supplemented by work on vehicle subsystems and also propulsion options analyses, which could see future use of Space Exploration Technologies' (SpaceX) new Merlin engine. Ground-based experiments will include high-temperature ascent and re-entry testing with realistic aerodynamic loads.

The goal of FAST is to develop technologies for aircraft-like space access operations and to spin those out to the private sector while delivering on the objectives for AFRL's Operationally Responsive Spacelift military programme.

The ORS X-aircraft concept is a 13,600-27,200kg (30,000-60,000lb) vehicle capable of vertical take-off and horizontal landing, reaching low-Earth orbit using liquid oxygen and RP-1 grade kerosene or methane rocket power, with engine-out and full-envelope abort capabilities.

Future work might see a FAST-2 demonstrator launched by a SpaceX Falcon 9 or Orbital Sciences Minotaur rocket for a Mach 12 to M20 test flight.

The current FAST2C demonstrator design is 13.7m (45ft) long, using two of Challenge Space's Chase-10 engines, has a dry mass of 7,200kg and gross lift-off weight of 27,200kg. It has a hot structure using carbon-carbon for much of its thermal protection system, with carbon silica nose panels.

A second design, which uses four SpaceX Merlin engines and is designated FAST4M, is about 18.3m long and has a dry weight of 13,000kg, similar to a Boeing F-15E. However, the maximum take-off gross weight would be 100,000kg.

Over the next four years an X-vehicle airframe design for a future reusable launcher will be ground tested under the US Air Force Research Laboratory's $70 million Fully Reusable Access to Space Technology (FAST) programme.

The airframe testing is to be supplemented by work on vehicle subsystems and also propulsion options analyses, which could see future use of Space Exploration Technologies' (SpaceX) new Merlin engine. Ground-based experiments will include high-temperature ascent and re-entry testing with realistic aerodynamic loads.

The goal of FAST is to develop technologies for aircraft-like space access operations and to spin those out to the private sector while delivering on the objectives for AFRL's Operationally Responsive Spacelift military programme.

USAF Aerospace Research Pilot School:

Events of the late 1950s disclosed the need for aerospace pilots trained for work in advanced aircraft and manned space research programs. Thus in 1961 the research pilot or "aerospace training" phase was added to the Test Pilot School’s curriculum. Now called the Aerospace Research Pilot School (ARPS), it is constantly changing to keep its course of instruction, test methods, and training vehicles ahead of the anticipated needs of future test programs.

The Phase II flying curriculum fortifies the flight-test training of Phase I by providing additional experience in high-performance and unusual aircraft. It also provides space- and research-related flight experience by using special and conventional aircraft in configurations with research-vehicle handling qualities in typical research flight profiles. This experience includes exposure to zerogravity, pressure suit survival, rocket propulsion, reaction control handling, energy management, variable stability, and lifting-body flight profiles and landing characteristics.

Just imagine if the USAF/NASA program in the 1960s that this was to be a part of, with reusable spacecraft landing and taking off conventionally hadn't been scaled back, and this school hadn't been folded into the Test Pilot school...

Because that means you don’t have a disposable component you have to obtain, load, and test. Which means that your turnaround time is much much less for a reusable vehicle. Also, using parachutes limits how heavy a vehicle you can send up, since there is a finite limit on how much weight chutes can support.

The DC-X program, if carried through to completion, would have resulted in a RLV that was stupidly cheap to launch (less than a million bucks per trip), could be turned around and launched again in 24 hours or less, and that didn’t require enormous ground crews to service and launch. All of which is why NASA killed it.

My problem with DC-X concept is that it relies on complex engines and fuel in order to get on the ground safely. If anything breaks, you're dead. It might be a great idea for a space UAV, but not for man rating.

Wings and aerodynamic flight controls are far more reliable than rocket engines, and considering the fuel costs of vertical landing, I doubt they cost much more in weight. Wings also allow quick turn arounds as well, as long as the basic vehicle isn't such a complex mess like the Shuttle.

Actually, the DC-X concept is living on in private space enterprise.

That said, the DC-X idea is much lighter (needs a lot less heat shielding) and the engines were actually fairly simple, relatively speaking.

Wings are “more reliable” but have to have heat shielding for reentry, and one failure there.....

Let’s not get that boondogle out of the closet. It died a natural and timely death, and the DC-X needs to remain dead.

Stupidest idea I’ve ever heard of, after the Pogo XFY-1 aircraft.

Look at the space shuttle. See the huge external tank and two solid rocket boosters? That’s just to get it up into orbit. The DC-X promised a single stage to orbit, and it promised to still have enough fuel for a powered landing?

Never in a million years would that concept get beyond the desert testing stage, which is why when the prototype was damaged in a landing test, they never bothered to rebuild it.

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