Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from hogtown.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests) ID ; Fri, 15 Mar 91 01:26:35 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Fri, 15 Mar 91 01:26:28 -0500 (EST) Subject: SPACE Digest V13 #267 SPACE Digest Volume 13 : Issue 267 Today's Topics: Space Station 'Fred' Restructuring Re: Reliability O-Ring and Feynman Re: Terraforming of Venus Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription requests, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: 13 Mar 91 14:56:13 GMT From: eagle!sei_4.lerc.nasa.gov!dbm0000@ucbvax.Berkeley.EDU (Dave McKissock) Subject: Space Station 'Fred' Restructuring For anybody interested in "what's happening" with Space Station Freedom Restructuring ... Space Station Freedom Level II recently (2/26/91) issued a Restructuring directive. This directive was issued "to document the Program restsructuring decisions and to ... use the Program restructuring decisions as a basis for updating the Program requirements baseline." The directive identifies the major technical decisions made during the restructuring process using the ISPDR (Integrated Systems Preliminary Design Review) baseline as the reference. A summary of the directive follows (an acronym list is at the end, & believe me, you'll need it!): 1.0 Revised Manifest ======================================================================== 1.1 Revised Assembly Sequence [Text in brackets like this is based on data in the Assembly & Maintenance Implementation Definition Document, Volume 1-Assembly, February 25, 1991] Date Flight Flight Components 11/95 1 FEL MB-1 Truss section with starboard inboard PV system, alpha joint, propulsion module platforms, passive dampers, MT, unpressurized berthing mechanism [Stage MB-1 is unpowered and passively stabilized in a gravity gradient flight mode in a 200 nautical mile orbit. Passive dampers maintain a Torque Equilibrium Attitude and rotation rates within acceptable capture limits for berthing or docking at the beginning of flight 2.] 12/95 2 MB-2 Truss section with CMGs, C&T, 2 propulsion modules (reduced capacity), temporary avionics [The Space Shuttle Orbiter is berthed to the UBM for all assembly operations on this flight. Attitude control authority is maintained by the Orbiter during joined operations. The CMG's are not activiated until flight MB-5. The PV solar arrays and radiators are deployed and activated. The propulsion modules are installed onto the platforms and activation/checkout is performed. However, no jet firings occur during SSF/SS joined operations. Following separation of the Orbiter from the SSF spacecraft, attitude control authority is maintained by the SSF spacecraft in a gravity gradient flight mode. At this time the SSF has attitude control and reboost capabilities.] 3/96 3 MB-3 Truss section with starboard TCS, UHF and KU-band antennas, SSRMS [The TCS and SSRMS are activiated for checkout purposes only. The TCS radiators are not deployed.] 6/96 4 MB-4 Truss section with IUD, MTS, GCP, cryo berthing mechanisms (2), node umbilicals, CETA cart (2), MT Batteries 9/96 5 MB-5 Aft port node, pressurized docking adapter, cupola 12/96 6 MTC MB-6 U.S. lab module core-A, system racks, 7 user payload racks, MBS (ASRMs required) 3/97 7 MB-7 Airlock, pressurized docking adapter, SPDM/MMD 6/97 8 MB-8 Truss section with port TCS, C&T (UHF antenna) 9/97 9 MB-9 Truss section with dry cargo berthing mechanisms(3), 2 propulsion modules (reduced capacity) 12/97 10 MB-10 Truss section with port inboard PV system, alpha joint, propulsion module platforms 3/98 11 MB-11 Aft starboard node, outboard PV spacer 6/98 12 MB-12 JEM module, JEM DDCUs & heat exchanger (ASRMs required) 9/98 13 MB-13 ESA Module, ESA DDCUs & heat exchanger (ASRMs required) 12/98 14 MB-14 Truss section with starboard outboard PV Module 3/99 15 MB-15 JEM exposed facility, JEM ELM PS, JEM ELM ES (ASRMs required) 6/99 16 MB-16 U.S. Hab Module Core-A, system racks (ASRMs required) 9/99 17 PMC MB-17 ACRV (ASRMs required) ======================================================================== 1.2 Revised Utilization Sequence Date Flight Flight Components 5/97 UF-1 8 rack M-PLM, cryo N2/O2 11/97 UF-2 8 rack M-PLM, dry cargo 5/98 UF-3 8 rack M-PLM, hydrazine 11/98 UF-4 8 rack M-PLM, cryo N2/O2, dry cargo 5/99 UF-5 8 rack M-PLM, hydrazine ======================================================================== 2.0 Revised Program Milestones MTC Phase Review October 1991 System Critical Design Review March 1993 Design Certification Review January 1995 Operations Readiness Review June 1995 First Flight Readiness Review September 1995 First Element Launch November 1995 Man-Tended Capability (MB-6) December 1996 Permanently Manned Capability (MB-17) September 1999 ======================================================================== 3.0 Revised Available Payload Volume -15 payload racks available in U.S. Lab at MTC (3 payload racks without N2 or vacuum services) -12 payload racks available in U.S. Lab after PMC -11 payload racks available in JEM/PM -23 payloads racks available in ESA/APM ======================================================================== 4.0 Revised Laboratory A will accommodate (at MTC and PMC): -Maintenance Work Station (1 rack) -Element Control Work Station (1 rack) -Avionics (1 rack) ======================================================================== 5.0 Revised General Configuration Features (MTC) -1 PV Module (including preintegrated truss section outboard of alpha joint) -1 Microgravity Lab (27 ft Module) -1 Node -1 Pressurized Docking Adapter -4 Preintegrated Truss Sections (inboard of alpha joint) -SSRMS/MBS/MT (simplified) -2 Propulsion Modules (downsized) -50 Mbps Ku-band Communications (downlink only) -8 Rack Logistics Carrier -Single-fault tolerant systems for Station survivability (manned & unmanned) ======================================================================== 6.0 Revised General Configuration Features (PMC) -3 PV Modules (including preintegrated truss section outboard of alpha joint) -1 Mictogravity Lab (27 ft Module) -1 Hab Module (27 ft Module) -2 Nodes -Airlock -2 Pressurized Docking Adapters -7 Preintegrated Truss sections (inboard of alpha joint) -NASDA JEM/EF/PLM -ESA APM -ACRV -MSS -4 Propulsions Modules -50 Mbps Ku-band Communications (Downlink only) -8 rack and 20 rack logistics carriers -single-fault tolerant systems for Station survivability plus two-fault tolerant systems for Crew safety including the functional redundancy of the ACRV ======================================================================== 7.0 Follow-on Phase Additional Features (not included in revised budget) -4th PV Module (including preintegrated truss sections outboard of alpha joint) -Hab B with 8 person crew accommodations (27 ft Module) -Lab B (27 ft Module) -2nd ACRV -Node 4 -Node 3 -300 Mbps downlink -2nd Cupola -Closed Loop O2 -Ultra Pure water -Resistojets/Waste Gas Collection -Traffic Management capability ======================================================================== ACRONYM LIST ACRV Assured Crew Return Vehicle, or Astronaut Crew Rescue Vehicle, depending upon which source you use APM Attached Pressurized Module ASRM Advanced Solid Rocket Motor CETA Crew & Equipment Translation Aid CMG Control Moment Gyro C&T Communications & Tracking DDCU dc-to-dc converter unit ELM-ES Experimental Logistics Module Exposed Section ELM-PS Experimental Logistics Module Pressurized Section GCP Gas Conditioning Pallet IUD Integrated Utilities Distribution JEM Japanese Experiment Module M-PLM mini Pressurized Logistics Module MB Manned Base MBS Mobile Base Support (get's attached to the MT) MMD MSC Maintenance Depot MT Mobile Transporter MTC Man Tended Capability MTS Module-to-Truss Support PM Pressurized Module PMC Permanently Manned Capability PV Photovoltaic SPDM Special Purpose Dexterous Manipulator SSRMS Space Station Remote Manipulator System TCS Thermal Control System UBM Unpressurized Berthing Mechanism -- ----------------------------------------------------------------------- Dave McKissock sakissoc@mars.lerc.nasa.gov NASA Lewis Research Center, Cleveland Ohio. Opinions expressed herein probably bear absolutely no resemblance to the official NASA position. ------------------------------ Date: 13 Mar 91 17:18:45 GMT From: news-server.csri.toronto.edu!utgpu!utzoo!henry@rutgers.edu (Henry Spencer) Subject: Re: Reliability In article <9103130329.AA14348@cmr.ncsl.nist.gov> roberts@CMR.NCSL.NIST.GOV (John Roberts) writes: >>...if your thrusters explode when fired continuously... and we very nearly >>sent Galileo up with thrusters that did exactly that. > >In a way, we did. Those same thrusters are still in there. They haven't >exploded, however. If memory serves, there were some small changes to the feed system that *should* have eliminated the problem. The thrusters are still being fired only in pulses, just in case, and they are being "burped" regularly to avoid problems with decomposition. >To get back to your original comment, what can NASA *do* that's better than >what it's been doing? If they build multiple probes for a multiyear mission, >should they launch all of them at once, and possibly let the same unforeseen >design problem zap all of them? Or should they keep some on Earth, and put >up with the heat about overspending and probes that could have been used >gathering dust in museums? Neither. Launch in pairs to guard against random failures. Build backups in case of systematic failures, and if there are no such failures, *launch the backups anyway*, possibly on somewhat different missions. In short, be prepared for the possibility of failure, instead of betting the farm on 100% success. (If you think this comment should also be applied to the manned program... yes.) >for each project, build *one* probe for launch, designed to be as resilient >as possible, and do everything you can to keep it alive. If problems start >to come up, begin thinking about what you could have done better. If the >mission fails, do your utmost to find out why it happened (NASA seems very >good at this), then start begging for money for another probe. That way, >when you start construction of the replacement... What do you mean, "when"? The correct word is "if". In the current state of affairs, the odds of getting a replacement for a failed mission approach zero. "If you couldn't do it right once, why should we give you more money to try again?" If you always promise success, and don't insist on planning for failure, people assume you don't need to plan for failure, and that any failure is a sign of your incompetence. -- "But this *is* the simplified version | Henry Spencer @ U of Toronto Zoology for the general public." -S. Harris | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 11 Mar 91 15:02:57 GMT From: elroy.jpl.nasa.gov!sdd.hp.com!spool.mu.edu!news.nd.edu!news.cs.indiana.edu!nstn.ns.ca!Iris1.UCIS.Dal.Ca!roberts@ames.arc.nasa.gov (Greg Roberts) Subject: O-Ring and Feynman I recall seeing Dr. Feynman on television during the hearings, and doing that wonderfully simple experiment to show elasticity in O-Ring material at low temperature using his glass of ice water. The fact still remains, the cause of the shuttle failure is directly related to the failure of the O-Ring. If there had been no blow-by, no erosion, integrety of seal etc., there would have been no combustion of ET propellant. The failure of the support is a result of the wall failure at the lower attach point, which then caused rotation about the upper attach point, breaching the upper dome. You might also want to note that the force of the gasses through the ring was significant enough for the guidance computers to notice, mis-interpret as a gust load, and gimble the SRB nozzle, compounding the problem. I recall reading the torque loads at ignition due to 'twang' were well within limits, and not as severe as on previous missions. However, the gimballing limits on the SRB post launch were the most severe ever recorded. I have the most absoluterespect for Feynman. He took at the technical mumbo jumbo from the MT engineering staff, and made it crystal clear so that anyone, including Neil Armstrong, could understand it. Temperature. O-Ring. Failure. Greg Department of Mechanical Engineering, TUNS ------------------------------ Date: 7 Mar 91 19:39:02 GMT From: elroy.jpl.nasa.gov!sdd.hp.com!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!pitt!nss!Paul.Blase@ames.arc.nasa.gov (Paul Blase) Subject: Re: Terraforming of Venus JD> Ah, why not 'just' set up lots and lots of surface JD> based 'rockets', and jet the atmosphere away at very high JD> velocities? You might change the rotation rate *and* dump the JD> excess gas at the same time. Very high is defined as at least JD> Solar Escape Velocity; jetting 89 atmospheres of CO2 into the JD> inner system might be seen as pollution :) People on this echo tend to forget that progress is being made in fields other than rocket science. How about creating an organism that can take whatever is in Venus' atmosphere and turning it into something that we can handle? Some kind of cross between an algae and a Portugese Man-O'War that can float in the atmosphere. I'm sure that it could even create limestone to get rid of the excess CO2 if required. (You still might have to import a comet to provide water/hydrogen). --- via Silver Xpress V2.26 [NR] -- Paul Blase - via FidoNet node 1:129/104 UUCP: ...!pitt!nss!Paul.Blase INTERNET: Paul.Blase@nss.FIDONET.ORG ------------------------------ End of SPACE Digest V13 #267 *******************