From: skunk-works-digest-owner@harbor.ecn.purdue.edu To: skunk-works-digest@harbor.ecn.purdue.edu Subject: Skunk Works Digest V3 #78 Reply-To: skunk-works-digest@harbor.ecn.purdue.edu Errors-To: skunk-works-digest-owner@harbor.ecn.purdue.edu Precedence: bulk Skunk Works Digest Friday, 16 July 1993 Volume 03 : Number 078 In this issue: DC-X Test Program Status [rschnapp@metaflow.com (Russ Schnapp): Re: DC-X Test Program Status] See the end of the digest for information on subscribing to the skunk-works or skunk-works-digest mailing lists and on how to retrieve back issues. ---------------------------------------------------------------------- From: rschnapp@metaflow.com (Russ Schnapp) Date: Thu, 15 Jul 93 09:12:50 PDT Subject: DC-X Test Program Status I am forwarding this latest DC-X Test Program update from BIX: ========== space/long.messages #1346, from hvanderbilt, 8808 chars, Wed Jul 14 19:54:40 1993 - ---------- DC-X News, July 14th, 1993 Content-Length: 8756 Copyright 1993 by Henry Vanderbilt and Space Access Society. DC-X Test Program Status DC-X Background 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. DC-X Move To Flight Test Site Near Complete The news out of the DC-X test program this week is that the move to the White Sands Missile Range (WSMR) flight test area is winding down, apparently a bit ahead of schedule. As of today, word is that DC-X itself will be taken out of storage and moved to the flight test site this coming Friday, July 16th. It will be trucked over horizontally with no major disassembly. The craft is currently stored in a hangar at the White Sands ground test site, waiting for the ground support gear move and reassembly to be finished. 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" flight stability test series should begin shortly thereafter. These hops will consist of takeoff, sideways transition of several hundred feet, and landing, done under varying crosswind conditions. A lot of people will be keeping their fingers crossed during the first one. Note that the "bunny hop" series will be restricted to the thirty or so DC-X test crew members plus WSMR support personnel. No media, no VIP's, no public allowed -- not nobody, not nohow. Any stories you may have heard about the public getting in for these are, alas, wrong. First official DC-X flight will actually be the initial flight of the second test series, reaching higher speeds and altitude. This will be the one with speeches, hoopla, VIP's, and media coverage -- but still no admission of the general public. Chances are good for TV coverage, between NASA Select, local TV stations, and the national networks. Chances are also good that you'll be a whole lot more comfortable watching it on TV at home, as the test site is fifty miles of dirt road into a military reservation, run under military security, under the August New Mexico desert sun. You'll likely have a better view on TV too, since the "VIP" viewing site will be five miles from the pad. Tentative dates for the start of the first and second flight test series are July 29th and August 9th respectively. The exact dates depend on a lot of factors and likely won't be known until a couple days beforehand. The end-for-end transition maneuver won't be tried until the third, final flight test series. DC-X Followon: Political Status Background 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. SAS Action Recommendations SAS recommends that all you pro-SSTO activists stay tuned for further developments, but for now take a breather. You've done good; things seem to be in hand for the moment. Our thanks to everyone who's taken part in the campaign so far. For those who really must have something to do right now, continuing calls, faxes, and letters to the Senate Armed Services Committee members (Allen Sherzer has posted lists numerous times) will be helpful in raising awareness there in advance of the Senate deliberations. The current situation is that Representative Schroeder's HASC Research & Technology Subcommittee markup of next year's Defense Authorization bill, most recently scheduled for today, has been delayed indefinitely. It could take place early next week; it could be held up until September. The good news is that for the moment, DC-X followon funding seems to be non- controversial. Indications are it will be included in the subcommittee markup when that eventually does take place. As best we can tell, the delay is due to the ongoing "Bottom's-Up" policy review at DOD, as well as unresolved policy differences within the majority party, notably including the gays in the military issue. No telling when all the necessary compromises will be hammered out and the actual markup will occur. Once it does occur, look for things to happen fast -- the rest of the process in the House and Senate both should be complete within a week or two. Stay in touch and be ready to gear up again on short notice. Contingency alert: If, when it does occur, Schroeder's subcommittee markup does not give us the language we need for a DC-X followon, we will likely 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. Keep an eye on the nets for news of when the markup finally does occur, 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. 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. -- - ----- End Included Message ----- ------------------------------ From: Michael Chui Date: Thu, 15 Jul 1993 14:29:08 -0500 Subject: [rschnapp@metaflow.com (Russ Schnapp): Re: DC-X Test Program Status] - ------- Forwarded Message Date: Thu, 15 Jul 93 11:12:53 PDT From: rschnapp@metaflow.com (Russ Schnapp) Message-Id: <9307151812.AA21852@metaflow.com> To: mchui@cs.indiana.edu Subject: Re: DC-X Test Program Status > Russ: > What's the rationale for the tail-first landing attitude, vs. > a shuttle-like horizontal landing? (I did lurk during the discussion > on this topic on this mailing list, but I was too clueless about the > actual project to have completely caught on.) > > Michael Chui > mchui@cs.indiana.edu Efficiency. On a space vehicle, wings are, apparently, a rather cumbersome, heavy, and troublesome item to lug around. You already have an engine, which you needed to get to orbit. By the time you get there, your mass is so small that it doesn't take much propellant to generate large accelerations. Thus, you deorbit with a small burp, you use the hull as a lifting body, nose-first, during reentry, and then you flip and burn off the little bit of velocity you didn't lose through aerodynamic braking, via the engine. The tradeoff is a big, heavy, draggy wing that must withstand launch and reentry forces and heating so it can do its part in the very last stage of landing -- or -- a little bit of extra tankage and propellant to do the flip and hover with the engine you've already got. Actually, you probably don't even have to pay for extra tankage/propellant, since you would have needed some or all of it to counter the weight and drag of the wing on the way up, anyway. On the other hand, a wing is a rather reassuring structure. Engine failure is more likely to be survivable with a wing. The DC-X can survive engine failure in several flight regimes, but only because it is small enough to be recovered by a cluster of BIG parachutes. The real thing will be far too heavy for that option. Feel free to post this to skunk-works, by the way. It was a good question. ...Russ - ------- End of Forwarded Message ------------------------------ End of Skunk Works Digest V3 #78 ******************************** To subscribe to skunk-works-digest, send the command: subscribe skunk-works-digest in the body of a message to "listserv@harbor.ecn.purdue.edu". If you want to subscribe something other than the account the mail is coming from, such as a local redistribution list, then append that address to the "subscribe" command; for example, to subscribe "local-skunk-works": subscribe skunk-works-digest local-skunk-works@your.domain.net To unsubscribe, send mail to the same address, with the command: unsubscribe skunk-works-digest in the body. 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