henry@utzoo.uucp (Henry Spencer) (09/12/88)
ESA engineers are investigating a LOX-arm retraction problem that almost aborted the July 21 Ariane launch: the third-stage LOX arm stopped partway through its retraction sequence, but moved clear just in time for the launch to continue. SDIO fails to meet its Aug 1 target for revised recommendations on the Space Based Interceptor. A major DoD review of SBI is imminent, and with SDIO not having got its own act together, SBI's supporters are not optimistic. Flight readiness firing of the shuttle, Aug 10, goes okay. Remaining milestones before a late-Sept launch are one more SRB test, complete data review of the FRF, SSME post-FRF checkout, and successful repair of the RCS nitrogen-tetroxide leak. The FRF slipped a week after a valve problem aborted the Aug 4 attempt, but the valve replacement was completed ahead of schedule. (It now looks like the problem may have been sensor error.) The only real problem noticed during the FRF countdown was a bit of nitrogen in a fuel line; this may be a minor leak or a measurement error. Analysis of SRB aft-skirt loads will continue for several days. Infrared and mass-spectrometer hydrogen- leak detector results look clean. The next job [completed successfully] will be sealing the RCS leak. This will be done by cutting through the aft wall of the cargo bay and the forward wall of the OMS pod, clamping a clamshell fitting around the leaking joint, and filling it with sealant under pressure. The wall cutouts will be closed by bolting aluminum plates over them; the plates will be removable in case this needs to be done again, and will in fact be stronger (although heavier) than the areas of wall removed. Chinese controllers prepare to command reentry of Chinese satellite carrying a secondary West German materials payload. Inmarsat to issue RFP for new-generation Inmarsat series using multiple spot beams for marine navigation and communication. Soviet cosmonaut Anatoly Levchenko dies Aug 6 of a brain tumor. He flew on the Soyuz TM-4 mission to Mir last December, and may have been meant to be commander for the first manned mission of the Soviet shuttle. Spacehab and NASA sign deal giving Spacehab six partial shuttle flights, starting 1991, with payment deferred until after each flight. SDIO begins work on "Super", a survivable solar array hardened against the Van Allen belts, lasers, particle beams, and nuclear explosions. It will be flight-tested in 1993, maybe from the shuttle, and the test might carry piggyback experiments that could benefit from having 5-10kW of power available. Super is not yet slated for any particular uses, but the Boost Surveillance Tracking Satellite is an obvious candidate. Also underway is a less ambitious project called Scopa, started by the USAF and now getting some SDI funding too. The idea here is to put small concentrators over the individual cells of a solar array, with the concentrators designed so that light coming in at an angle will not reach the cells themselves. This shields the cells against laser attack from any direction except precisely head on. A 500W Scopa panel will fly in FY1990. SDI studies methods of retrieving malfunctioning nuclear reactors from orbit. One possibility is using a modified OMV to tow a failing reactor satellite to higher orbit. The study will probably recommend modifications to SDI's space-reactor project, SP-100, such as standard grappling fittings. SDI says a joint effort in space-reactor rescue with the USSR would be sensible, although no formal approach has yet been made. Cosmos 1900, the ailing Soviet nuclear radarsat, is due to reenter early in Sept. Shuttle-C unmanned heavylift shuttle derivative is gaining support as an interim heavylift booster, specifically for space-station assembly. The interest is especially strong since ALS no longer includes the goal of a near-term "interim ALS" heavylift booster. Phase 2 study contracts for Shuttle-C were awarded recently. It could be ready in 1993-4, using SRBs, tank, and engine section identical to the shuttle, but with the rest of the orbiter replaced by a cylindrical payload shroud. Payload to low orbit could be 178 klbs. Five shuttle-C launches could replace thirteen shuttle launches (out of twenty) in station assembly. (There is a problem in that the station people must plan on using shuttle launches unless/until Shuttle-C is officially funded for development.) Initial Shuttle-C SRBs would probably be drawn from the stock of pre-Challenger SRBs still in storage but no longer considered safe for manned flight. No attempt would be made to recover Shuttle-C's SSMEs; they would be SSMEs that are near the end of their rated lives as shuttle engines. NASA is no longer hoping for more than about 10 flights per SSME, and this will create a substantial pool of "retired" engines by the early 1990s. SSME recovery for Shuttle-C is considered too complex and costly. Various payload masses could be accommodated by using either two or three SSMEs, running them at either 100% or 104% of rated thrust, and by using either ordinary shuttle SRBs or the new ASRMs which will be available in the 90s. A three-SSME, 104%, ASRM Shuttle-C could launch 190 klbs into low orbit from the Cape. Development costs including first flight are estimated at $1.9G, although NASA thinks that number (derived from general cost models rather than detailed analysis) is too high, given that the only major work needed is the payload shroud and the return to production of orbiter aft thrust structures. A generally-favorable OTA report said that $800M should be adequate; NASA is studying the issue. The OTA study said that Shuttle-C is not cost-effective if flight rate rises above 2-3 flights per year, given its high incremental costs ($235M per launch), but it could be quite cost effective at those rates as a way of offloading the shuttle. Inmarsat awards $8M contract to China Satellite Launch and Tracking Control General to provide tracking/telemetry/command services for the Pacific-area Inmarsat 2 satellites, starting in 1990. A dedicated tracking station near Beijing will be used. -- NASA is into artificial | Henry Spencer at U of Toronto Zoology stupidity. - Jerry Pournelle | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
mce@tc.fluke.COM (Brian McElhinney) (09/13/88)
henry@utzoo.uucp (Henry Spencer) writes: > No attempt would be made to recover Shuttle-C's SSMEs; they would be > SSMEs that are near the end of their rated lives as shuttle engines. > NASA is no longer hoping for more than about 10 flights per SSME, and > this will create a substantial pool of "retired" engines by the early > 1990s. So SSMEs do not last forever. :-) Some questions: 1) How much does a single SSME cost? They can't be cheap! 2) What was the intended number of flights per SSME? 3) Does NASA's latest budget include the costs of a new SSME every ten flights? Brian McElhinney mce@tc.fluke.com
henry@utzoo.uucp (Henry Spencer) (09/15/88)
In article <5163@fluke.COM> mce@tc.fluke.COM (Brian McElhinney) writes: > 1) How much does a single SSME cost? They can't be cheap! It depends on what assumptions you make, but no, they are not cheap. > 2) What was the intended number of flights per SSME? I think they started out hoping for 50. Then they scaled it back to 20. Now it's 10. > 3) Does NASA's latest budget include the costs of a new SSME > every ten flights? Three new SSMEs every ten flights, actually. I don't know whether it's explicitly in the budget, but with all the trouble they've been having with the SSMEs, I would expect so. -- NASA is into artificial | Henry Spencer at U of Toronto Zoology stupidity. - Jerry Pournelle | uunet!attcan!utzoo!henry henry@zoo.toronto.edu