#90 November 1995
Section 126.96.36.199.090.of the Artemis Data Book
Space Access Update is Space Access Society's when-there's-news publication. Space Access Society's goal is to promote affordable access to space for all, period. We believe in concentrating our limited resources at whatever point looks like yielding maximum progress toward this goal.
Right now, we think this means working our tails off trying to get the government to build and fly a high-speed reusable rocket demonstrator, one or more "X-rockets", in the next three years, in order to quickly build up both experience with and confidence in reusable Single-Stage To Orbit (SSTO) technology. The idea is to reduce SSTO technical uncertainty (and thus development risk and cost) while at the same time increasing investor confidence, to the point where SSTO will make sense as a private commercial investment. We have reason to believe we're not far from that point now.
Our major current focus is on supporting the govern-ment's fully reusable single-stage rocket technology programs, the low-speed DC-X, and its high-speed followon the X-33 NASA/DOD/industry cooperative project.
With luck and hard work, we should see fully-reusable rocket testbeds flying into space repeatedly later this decade, and practical orbital transport projects getting underway. Join us, and help us make this happen.
To join Space Access Society or buy the SSTO/DC-X V 3.0 video we have for sale (Two hours, includes all eight DC-X flights, X-33, DC-X and SSTO backgrounders, aerospike engine test-stand footage, plus White Sands Missile Range DC-X pre and post flight footage) mail a check to:
Space Access Society (SAS)
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Phoenix AZ 85044
SAS membership with direct email of Space Access Updates is $30 US per year; the SSTO V 3.0 video is $25, $5 off for SAS members, $8 extra for shipping outside the US and Canada, VHS NTSC only.
The severe drawbacks old SSMEs (Space Shuttle Main Engines) and the powerful vested interests that work to favor their use nonetheless] would [not] matter if alternatives to SSME weren't available, alternatives possibly more suitable to the overall purposes of the X-33. We're reasonably well-aquainted with two such liquid-oxygen/liquid-hydrogen (LOX/ LH2) engines.
The D-57 was designed as a high-energy upper stage engine. Sea-level thrust is ~70,000 lbs, vacuum thrust ~90,000 lbs, reports onthrottleability vary. Engine weight is ~2100 lbs, giving a relatively poor takeoff thrust-to-weight of 33:1 (SSME sea-level T:W is ~50:1) but reportedly engine weight could be relatively easily shaved to yield takeoff T:W of ~45:1.
Over thirty D-57s were built; reports on the number currently available vary widely, but the Russians never throw anything away... Between six and eight D-57's could power an X-33 in the size range currently contemplated. Over 150 test-stand firings took place, with total run time near ten hours. We've seen claims that D-57 is too prone to explosive failure for X-33 use; we haven't seen the data on which those claims are based. We note that just about all rocket engines blow up a few tests stands early in their test programs; such teething problems aren't necessarily relevant to flight safety.
We don't assume D-57 is certain to be suitable for X-33; we do recommend strongly that its suitability be thor-oughly explored as soon as possible.
Numerous sources indicate that the P&W RL-10 (a version of which powers DC-X) can be relatively easily upgraded to 26,000 lbs thrust sea-level, 35,000 lbs thrust vacuum, with total engine weight staying ~400 lbs, possibly less. This would yield a sea-level T:W of 65:1, actually better than SSME, though we should note both that this would be at lower-than-SSME specific impulse ("Isp", effectively a measure of fuel-efficiency) and that the more complex plumbing required for a multi-RL-10 installation would offset some part of the weight saved. Between 16 and 20 such upgraded RL-10's could power an X- 33 of the size currently being contemplated.
The various modifications required for SSTO suitability (increased chamber pressure, deep throttling, extendable nozzle) have already been tested separately. One option for an RL-10 powered X-33 in the event of delays in upgraded RL-10 delivery could be initial flight test using existing RL-10 versions and a reduced propellant load.
We recommend strongly that work on such an enhanced RL-10 begin ASAP. Even absent SSTO applications, numerous upper-stage applications exist for a very similar (no deep throt-tling needed) engine. We further recommend that DC-X style lean management, lean budget, and tight schedule be applied to this effort. There is neither time nor money for business as usual.
The House-Senate conference on the FY'96 Department of Defense (DOD) Appropriation bill finished last week with $25 million for reusable rocket work in support of X-33 at USAF Phillips Labs. This is less than we'd hoped for, given the late surge of support we've been seeing in the Senate, but still $25 million more than the Administration originally asked for.
The House had voted to authorize $100 M and appropriate $50M, while the Senate version DOD funding bills had no reusable rocket funding coming into the conference. The new Senate support we've seen came too late to add anything to the Senate versions, so we likely ended up with $25 million by a straight splitting of the difference between the House's $50 million and the Senate's zero. Chances are we'll do better here next year. We've built some foundations.
Meanwhile, the House, in a surprising but not unprecedented move, voted to reject this conference committee's overall results at the end of last week. The rejection was over a variety of issues:
None of these issues were SSTO-related.
Likely, what will happen is that a new conference will take place, limited strictly to the controversies that sank this version. Chances of our either gaining or losing anything from the current $25 million funding for DOD reusable rocket work are small. We'll be keeping an eye on things, of course.
Meanwhile, Congress and the White House thrashed out a six-week "Continuing Resolution", legal authority for the government to go on spending more or less at the current rate until mid-November, despite the start of Federal Fiscal Year 1996 on October 1st without a new budget signed into law yet. This is nothing unusual in recent years.
The HUD, VA, and Independent Agencies (NASA) Appropriation bill will be the second to last of over a dozen major appropriations bills dealt with. (The only appropriation after it on the list is for running the District of Columbia.) The critical-to-X-33 HUD, VA and IA conference, last we heard, was scheduled for October 16th. We'd guess this will slip a bit more before everything's taken care of.
The main issue in this conference, as far as we're concerned, is still getting the Senate's $63 million for X-33 accepted over the House's $43 million. The previous alerts on this matter still stand; if you have a Senator or Representative on the HUD, VA, IA Appropriations subcommittees and you haven't yet contacted them per recent Alerts, please do so. Just because the formal conference is delayed doesn't mean the staffs aren't quietly working on the issues.
ASI Editor's Note (7 Feb 1999): Space Access Society's Web Site
Contents of this issue of Moon Miners' Manifesto