NASA group, using Landsat 5 images, finds arc of sinkholes in Yucatan, confirming earlier geophysical evidence suggesting a major impact crater there. The significance is that this may be the one that caused the Cretaceous-Tertiary extinction.
Hawaii Space Development Authority selects Palima Point and Kahilipali Point as possible sites for a commercial launch facility.
NASDA does successful 350s test run of LE-7 at nearly full power. [Notable because this engine has been prone to fires and other signs of troubled development.]
Space station in trouble as House panel votes to kill funding. [As usual, I will refrain from detailed reporting of already-dated news.] NASA brass startled: "this came from the committee that asked us [last year] to do something about the space station design... We thought we had done what we were supposed to do." Committee staff prepares "sample distributions" of funding with and without station, carefully calculated to cause uproar since the with-station one shows cuts in a wide range of other NASA work. [It's depressing to see how many otherwise intelligent people swallowed this propaganda tactic hook, line, and sinker, and concluded that the only hope for those programs was to kill the station.]
Successful launch of NOAA-D, a low-orbit weather satellite, from Vandenberg aboard an Atlas. NOAA-D will become NOAA-12, replacing NOAA-10 which is nearing the end of its life. NOAA-D is an old bird, having spent several years in storage because its predecessors lasted longer than expected.
Germany and Japan to propose recoverable microgravity capsule to carry payload up to 200kg. Launch would be via ISAS's Mu3S2 launcher, with recovery in Australia.
Arabsat 1C booked on Ariane, apparently abandoning earlier booking on Long March. The official excuse is complications in the infrastructure and support needed to launch on Long March. [One might wonder a bit whether political pressure was a factor. The Arabs are vulnerable to US pressure just now...]
Arianespace puts ERS-1 launch on hold pending investigation of yet another problem with the third-stage engine: a pressure drop in the hydrogen system during ignition. The drop is within margins but is not well understood. Postponement of the May 3 launch will tie into some reshuffling of payloads expected anyway: Anik E1, set for July, will be postponed until E2's antenna deployment problem is better understood, and Japan's Spacebird B will not be ready for its scheduled November launch.
Columbia prepares for Spacelab Life Sciences mission. This will be the first flight of the big pressurized Spacelab module since Challenger, and also the first flight of the animal-holding facility since its troubled initial test in 1985 (it's been improved). Also to be tested is a new "hood" facility to permit free-fall work on chemicals or animals, using air flow to contain "particulate matter" and keep it from drifting around the cabin; for this initial test, only some test materials will be tried. The crew are both experimenters -- three MDs and one medical PhD out of a crew of seven -- and guinea pigs themselves, with orbit chosen to permit landing without shifting the crew's day/night cycle and plans to take the crew out of the orbiter at once so that medical tests can start within 45min of landing.
Magellan succesfully completes its first mapping cycle, still running well despite various woes (including a 32-hour outage in early May). The second cycle will fill in the gaps in the first-cycle maps, including as much of the south polar region as possible. It will also try constant-angle right- looking mapping in addition to the varying-angle left-looking method used for the initial planetary map; this will give better comparisons to earlier fixed-angle data from Earth and Venera 15 and 16, and will determine how the varying angle affects imaging. Also on the agenda is looking for changes in the surface since the first cycle, and experimenting with new radar techniques: interferometry for ultra-precision altimetry, stereo imaging, imaging at a different polarization angle, and doubling the resolution of normal imaging by doubling pulse rate.
In the longer term, tentative plans have been made for the third through seventh cycles. The two big unknowns are whether Magellan can successfully aerobrake, and whether interferometric altimetry will work. Aerobraking into a circular orbit would make gravitational measurements vastly more accurate, improve radar resolution from 400ft to 150ft, and make a constant look angle possible for large-scale mapping. The main worry is limited knowledge of Venus's atmosphere, especially at a time of high solar activity. Some data on this will be had when Pioneer Venus, starting to run low on fuel, makes a kamikaze dive into the atmosphere in 1992. A secondary worry is Magellan's flakey attitude-control computer, since tumbling during aerobraking could be fatal. Heat load and drag -- estimated at about 1 pound -- would be tolerable. Also being looked at are other complications of the lower orbit: a faster mapping cycle, more blockage of communication by the planet, less average solar power, and greater heating by sunlight reflected from the planet (a particular concern because Magellan is already running hotter than expected). The other big question mark, interferometric altimetry, could permit detecting changes of surface height down to a few centimeters by combining data from 2-3 orbits, if position and timing of the mapping pulses can be determined accurately enough.
If a review board in August okays the two biggies, the tentative schedule for cycles 3-7 -- not yet formally approved or funded -- is:
3. Radar modes. Various techniques, including interferometry, to get altitude information out of the main radar. Higher resolution. Bistatic radar, with Magellan transmitting and Earth stations receiving. Polarization experiments. 4. Gravity measurements, plus more radar-mode work. 5. 5-8 months of aerobraking. 6,7. Mapping and gravimetry in circular orbit.
If aerobraking is rejected, cycles 5-7 will do more radar experiments and re-image parts of the planet to look for changes. All of this is somewhat subject to further equipment failures. In particular, one of the two tape recorders is already dead, and everyone is crossing fingers that the other one lasts; gravimetry (which doesn't use the recorder) has been postponed to get more imaging done early.
Matra Marconi Space proposes a major enlargement of the France/Italy/Spain Helios spysat project. Helios is currently one Spot-derived spacecraft to fly in 1994, plus a second as a spare. MMS proposes launching the second one too, then proceeding to a second-generation pair adding infrared instruments, and then a third group adding some specialized radarsats and eavesdropping satellites. (An experimental eavesdropping package is slated to fly on the first Helios.) MMS says the Gulf War has brought out the need for sensors that can work in darkness and through cloud.
First Hubble images of Jupiter.
"Forum" article by Thomas J. Frieling, an aerospace historian, proposing to forget ALS and Shuttle-C in favor of an improved revival of the Saturn V. He suggests, in particular, modernizing the computers, using more modern materials for the tanks, and re-engining the second and third stages with SSMEs for higher performance and one less engine production line. Launch would be from KSC: one VAB bay would be revised to restore Saturn V stack and checkout capability, a new mobile launch platform and umbilical tower would be built (the existing ones having been converted for shuttle use), and Pad 39C -- planned and provided for but never built -- would be built as the launch site. His basic argument is that while this plan is not cheap, it makes better use of existing facilities and involves fewer technical risks than the all-new ALS, while having a much larger payload.
Lightweight protocols? TCP/IP *is* | Henry Spencer @ U of Toronto Zoology lightweight already; just look at OSI. | henry@zoo.toronto.edu utzoo!henry