Letter from USAF Capt. D.B. Eckstein, observing that if you're going to redesign the space station to go up in one big launch (Option C or similar), it's silly to do all the engineering needed to put three SSMEs on the back, and then throw away the SSMEs. Launch it on Energia instead.
Possible sighting of the heliopause by the Voyagers... No, they haven't flown through it, but they've seen unusual radio activity in the 2-3kHz band [which is impractical to observe from Earth due to the ionosphere getting in the way]. The cause is not known for sure, but the best guess is that the surge in the solar wind caused by last summer's strong solar activity is hitting the heliopause. If this is what's doing it, then it gives us the first solid estimate of the distance to the heliopause, based on the known velocity of the solar wind: 90-120 AU. This gives the Voyagers a good chance to reach it before they die; Voyager 1 is now at 52 AU and Voyager 2 at 40 AU.
Fourth [and final, I think] static test of Hercules's upgraded Titan SRB design successful at Edwards.
Endeavour launch target date revised to June 20, after replacement of the turbopump with the suspect spring. KSC workers are going over the other SSMEs to make sure none of them have the mistreated springs.
Proton failure May 27, thought to be a second-stage problem, perhaps a pressurization or tank-wall failure.
FAA officials attend the Paris air show in hopes of sounding out their counterparts from other countries on exactly what misgivings they have about relying on the DoD-controlled GPS system.
Station supporters in the House are skeptical that the existing station design is getting a fair shake in the redesign comparisons. The latest hint that Goldin may be trying to stack the deck is that he wanted to bring only redesign people -- no SSF program staff -- for his House testimony June 8 (he was told firmly to bring both).
And speaking of the station redesign, it's not doing so well. The three options will all overrun Clinton's cost targets, there will not be a big cost difference between them, and none will have a major cost advantage over the current program. (Goldin allegedly would like to see Option C come out ahead on costs, and reportedly some redesign-team members are considering formal protests of what they see as biased assessments.) Nor will any of them permit advancing permanent manning to 1998. However, streamlining management now and operations later will produce noticeable costs savings compared to the current program.
The politics of the redesign will be messy. Clinton will want to be sure he's got realistic cost estimates before adopting the project as his own. Congressional supporters will see a lack of massive cost savings as a good reason to forego redesign altogether, and Congressional opponents will see it as more ammunition for killing the project.
Were the US starting from scratch, there is considerable opinion that something like Option C -- launch in one piece -- would be the preferred approach. But so much re-engineering would be needed that C supporters are having trouble keeping the pricetag much below that of Option B (trimmed-down design using current SSF hardware). Tactics being talked about include cannibalizing orbiter Columbia, farming out main structure construction to Russia (Russian manufacturers refused to do a short-notice bid on what they considered an inadequately-detailed RFP, but there is still interest), and closing down Spacelab operations early to save money. Option C is also having trouble keeping weight down, even assuming the availability of the proposed lightweight ET. C would also have serious political problems -- all three international partners reportedly will bail out of the program if it is chosen.
The Sampex US/German magnetospheric-science satellite has found what it was sent to find: a belt of cosmic-ray-derived particles imbedded in the inner Van Allen belt. Its existence has been suspected for some time, and investigating it was one of Sampex's primary missions.
DC-X static tests underway, going fine so far with 65% thrust reached. On May 27 the crew ran one test, shut down and serviced DC-X, and then ran another, within eight hours.
Magellan aerobraking now estimated at 71 days, based on results from the first week. Aerodynamic heating is less than expected, fuel consumption is below planned, and Venus's atmosphere is behaving more or less as expected. Fuel consumption is 40g/pass instead of the 50g/pass budgeted, with a good bit of the thruster activity in roll (where the aerodynamic stability does not help -- there was a proposal to tilt the solar arrays for aerodynamic roll control, but it was rejected as unnecessarily risky); small changes may be made to try to reduce roll torques. Drag is 15-30% above the best-guess atmosphere model's predictions, but within the range predicted by more conservative models. JPL has rejected suggestions to "push more" now that there is solid data on the atmosphere.
Taiwan's National Space Program Office is about to release an RFP for foreign contractors to help it build its first satellite. The current target is that 25% of hardware money be spent in Taiwan, including doing part of all the major phases -- design, integrate, and test. Rocsat-1 will weigh about 400kg in LEO, with payload split about equally among solar-terrestrial physics, ocean-surface monitoring, and comsat technology. The sketched-in Rocsat-2 will focus on comsat technology. Launcher selection will be next year. International teaming is being done not just because of Taiwan's limited expertise, but also because Taiwan is not a member of the UN and hence lacks standing to apply for frequency assignments etc.
With station redesign hitting snags, various outsider proposals are being talked up by various advocates. Conflict-of-interest rules have made it difficult for some to offer formal input to the redesign team, and there are differences of opinion about how open the team was to outside input. The official story is that they were willing to listen to any proposal with reasonable engineering credibility, but had to quickly narrow their focus to the most credible ideas because of the short deadline. Quite a few advocates of alternate designs are claiming that the team didn't give their concepts a fair shake, however [unfortunately, such claims were inevitable whether the redesign team was being fair or not, so it's hard to say how much credence they deserve]. Harwood's modular design, external-tank concepts, and inflatables have all come back out of the woodwork.
One scheme that AW&ST gives some detail on is Buzz Aldrin's "Eagle Science Station", which uses most existing Freedom components but defers the US habitation and lab modules in favor of a new small module for logistics and crew quarters. First, a Titan 4 would launch the US "node" station core, and an orbiter would follow with some truss, propulsion modules, and various bits of support hardware; the result would then be docked to Mir. Then another Titan would carry large solar arrays, followed by an orbiter with more truss and other hardware. Alternatively, the second pair of launches could come first, resulting in a "power tower" to lengthen shuttle extended-duration flights. Either way, science operations could start after the first four flights. The fifth launch would be a stripped-down Japanese module on a Proton, with a shuttle mission delivering the rest of the Japanese hardware and assembling it on the sixth. Seventh would be a Soyuz lifeboat on a Soyuz launcher, at which point the station could be permanently manned. Eighth would be ESA's Columbus module on an Ariane 5, ninth the US small module. Russian Progress freighters would be used for some of the resupply needs.
Investors are not exactly hurrying to sign up for the various LEO comsat schemes, e.g. Iridium. There is general agreement that the market is large and the technology is on hand. The problem is getting political approvals for offering worldwide service: much of the politicking will necessarily have to be done through the US government, and the government's history of slowness in such matters will be aggravated by the recent political turnover. A further complication is the possibility that Inmarsat, which is politically in a strong position for such activities, may enter the market. Investors think that only a few of the LEO-comsat proposals are going to succeed, they don't want to bet their money on the others, and so far it's not clear who the winners will be. Even Motorola, with its big-league resources, is behind schedule on getting investors for Iridium.
Altruism is a fine motive, but if you | Henry Spencer @ U of Toronto Zoology want results, greed works much better. | henry@zoo.toronto.edu utzoo!henry