DC-X is a low-speed flight regime testbed for a proposed reusable rocket- powered Single Stage To Orbit (SSTO) transport, McDonnell-Douglas Aerospace's "Delta Clipper". DC-X is intended to prove out rocket-powered vertical takeoff, nose-first lifting-body to tail-first flight transition, and tail- first landing. It is also intended to prove out rapid turnaround of a reusable rocket by a minimal ground support crew.
DC-X has already pretty much proved out rapid low-cost development of an advanced aerospace X-vehicle type engineering testbed by a small highly- motivated engineering team on a tight budget. Of course, that's been done before -- just not recently.
DC-X stands 40 feet tall, is 13 feet across the base, and is roughly cone- shaped, with a circular cross-section forward blending into a square base. The vehicle has four maneuvering flaps, one set into each side near the base, and sits on four landing legs. DC-X masses 22,300 lbs empty and 41,630 lbs fully fuelled, and is powered by four 13,500 lb thrust Pratt & Whitney RL-10- a5 liquid oxygen/liquid hydrogen rocket motors, each able to gimbal +- 8 degrees. The RL-10-a5 is a special version of the RL-10-a designed for wide throttling range (30% to 100%) and sea-level operation.
The single DC-X vehicle was officially rolled out of its construction hangar at MDA's Huntington Beach CA plant at the start of April, then trucked out to White Sands, New Mexico for ground and then flight tests.
As of Friday, June 18th, DC-X was through with its ground-test program, after a total of nine test-stand engine firings since May 20th. Starting Monday June 21st, the DC-X crew began moving the operation up the road to the White Sands Missile Range (WSMR) site where they're expected to begin flight testing in late July or early August.
With the end of ground testing, the DC-X program has accomplished a significant portion of its overall goals. The nine firings included tests that simulated all phases of takeoff, hover, translational flight and landing for the first flight test series. Key portions of the vehicle control software for nose-first to tail-first rotation maneuvers were also tested.
The DC-X ops crew is going to spend most of July under the hot desert sun, breaking down the ground support gear, trucking it over fifty-odd miles of unpaved road, and setting up again at the White Sands Missile Range flight test site. They're in the middle of this move now.
It's taking close to a month to break down, move, and set up again partly because easy portability simply wasn't a high priority in designing the ground support rig. The main concern was to put it together fast, cheap and simple out of off-the-shelf (in some cases, out-of-the-junkyard) components. Then too, monsoon season is coming to New Mexico -- any day now the area will start seeing thunderstorms coming up from the Gulf of Mexico more days than not, flooding dry washes and chewing up roads, with winds blowing the white gypsum sand that give the area its name into everything.
DC-X itself won't make the move until everything else is set up, sometime toward the end of July. It will be trucked over horizontally with no major disassembly. Until then, the craft is stored in a hangar at the White Sands ground test site.
Once launch site setup is done and DC-X moved, they'll be running a quick series of ground tests to make sure everything made it over intact. The first "bunny hop" stability test should take place shortly thereafter, featuring a takeoff, sideways transition of several hundred feet, and landing. A lot of people will be keeping their fingers crossed during that.
First official DC-X flight currently looks like happening in early to mid August. The exact date depends on too many factors to pin down closer than that -- weather, how many glitches show up after the move and how long it takes to fix them, and of course the results of post-move DC-X checkout, ground testing, and stability tests.
The current DC-X program is funded through flight test and data analysis this fall, and ends after that. There is an ongoing effort to get the US Congress to fund a three-year followon program, variously known as DC-X2 and SX-2 (Space Experimental 2). This could end up as a suborbital vehicle powered by 8 RL-10-a5 engines, capable of reaching Mach 6 (about 1/4 orbital velocity) and 100 miles altitude, built with orbital-weight tanks and structure, and able to test orbital grade heat-shielding.
There also may be some interest in followon testing of the original DC-X by other agencies, assuming the vehicle survives the initial test series intact. The basic DC-X specs point to considerably more speed and altitude capability than BMDO plans to use this summer. More on this when I know more.
The SX-2 program goal will be to demonstrate all remaining technology needed to build a reusable single-stage-to-orbit vehicle. Once SX-2 has been tested, all that should be necessary to produce a functioning reusable SSTO is to scale up the SX-2 structures and install new larger rocket engines.
Proposed FY '94 funding for SX-2 startup is $75 million. The money would come out of the $3.8 billion BMDO budget already pretty much agreed on for the coming year. Total SX-2 program cost over the next three years would be very much dependent on the contractor chosen and the details of the design, but would be on the order of several hundred million. This is the same order of magnitude as typical recent X-aircraft programs such as the X-29 and X-31.
SX-2 would start out under BMDO (formerly SDIO), so support from members of the House and Senate Armed Services Committees (HASC and SASC) is vital. The actual name they know SX-2 by is "followon funding for BMDO's SSRT (Single Stage Rocket Technology) program." The specific action we're calling for is for Congress to "fence off" $75 million in BMDO funding for this project next year -- we are not asking for any new funding authority, but rather for reallocation of existing funding toward a DC-X followon.
We need one last (fingers crossed) big push in the House of Representatives.
Lining up support in the House has overall gone well; all the key committee leaders are at least aware of DC-X Followon, and most seem to be favorably disposed. But Representative Pat Schroeder (D, CO, Chair of the House Armed Services Committee (HASC) Research & Technology Subcommittee) will be in charge of a critical funding procedure next week, and she could still use some encouragement.
Schroeder's subcommittee was supposed to "mark up" the FY' 94 Defense authorization weeks ago, but things have been delayed severely by the ongoing "Bottoms Up" review at the Pentagon. The latest word is that her subcommittee will perform the key markup around Wednesday of next week, July 14th. The next few days are a critical time for calls, letters, and faxes in support of fencing off $75 million of BMDO funds for an SSRT followon. Snailmail letters should go out before the end of this week, faxes and phone calls before next Wednesday.
Schroeder's phone is 202 225-4431, fax 202 225-5842, mail address is Representative Patricia Schroeder, 2208 RHOB, Washington DC 20515
Keep phone calls brief, polite, and to the point - tell whoever answers that you're calling to let them know you support fencing off $75 million of BMDO (formerly SDIO) funding for a followon to the Single Stage Rocket Technology ("SSRT") program. If you feel like it, throw in your favorite reason why this would be a good thing. If the person who answers wants to know more, answer their questions as best you can, otherwise thank them and ring off.
Letters too should should be brief, polite, and to the point, though you can go into a bit more detail as to why a DC-X followon is the neatest thing since sliced bread and good for the country too. Keep it under a page and state your basic point at the start.
Don't overdo it, but in general try to know who you're contacting and emphasize benefits likely to appeal to them. In this case, it might not hurt to mention one or two of the following:
Contingency alert: If Schroeder's subcommittee markup does not give us the language we need for a DC-X followon, we will have less than 24 hours to convince Representative Dellums, Chair of the full House Armed Services Committee, to insert the language during full Committee markup of the bill. Check the nets next week for when the markup actually occurs, and make sure to check in that evening -- if Schroeder doesn't go for it, we'll need to have everyone who can, call or fax Dellums the next morning. If she does go for it, we're not home free, but we'll have taken another large step forward on the path toward cheap access to space for all. Stay tuned.
Henry Vanderbilt "Reach low orbit and you're halfway to anywhere Executive Director, in the Solar System." Space Access Society - Robert A. Heinlein hvanderbilt@bix.com "You can't get there from here." 602 431-9283 voice/fax - Anonymous -- Permission granted to redistribute the full and unaltered text of this -- piece, including the copyright and this notice. All other rights -- reserved. In other words, intact crossposting is strongly encouraged.