henry@zoo.toronto.edu (Henry Spencer) (10/15/90)
ISAS discloses that the Astro-C, aka Ginga, X-ray astronomy satellite is losing altitude more quickly than expected, and has been since around the start of the year. Intense solar activity is blamed. At this rate it will reenter within a year. It was launched in 1987 for a nominally one-year mission, but is still active. NHK (Japan Broadcasting Corp) decides to launch its BS-3A tvsat without insurance. Launch is set for late August on an H-1. Reasons for the decision were undisclosed, but satellite insurance is expensive and NHK has been criticized lately for financial losses. NRC panel report says that the second phase of EOS should use several smaller spacecraft instead of one large platform. The first-phase platform really does benefit from having all its instruments studying the same area from the same angle at the same time, the panel says, but similar arguments offered for the second one have little merit. Space station makes progress, now only 7% overweight and 8% overpower, but the ranking Republican (Bill Green) on the relevant House Appropriations subcommittee has come out against the entire project, increasing House opposition. First AW&ST report of Magellan's silent periods. [As usual, I will skip detailed coverage because it's old news and was covered well here at the time.] However, the first radar pictures, taken before the troubles, look very good. Spacecraft now in safe mode pending troubleshooting. Speaking of safe modes, Hubble safed itself again Aug 19, for no obvious reason. This may be an occasional side effect of the way the solar arrays flap when going from darkness to sunlight; corrective software is in the works for that. Columbia hydrogen leaks tentatively attributed to tiny glass beads causing scratches on metal surfaces in the tank-attach fitting. The beads were found after cleaning of the fitting. Such beads are used in polishing and similar work, and parts of the plant that made the fittings use them. Soviets plan extensive EVA on Mir to move solar arrays from Kristall to Kvant 1, minimizing shadowing of arrays by each other, and to repair the damaged hatch. Internal wiring work will also be done for the solar-array move. Two EVAs will be done late this year, one for the hatch and one for preparations for the array move (assuming the first fixes the hatch). The actual move will occur early next year. Progress M-4, which docked to Mir Aug 17, carried parts for the wiring work. Progress M-4 is expected to be undocked in late Sept, and will do maneuvers simulating those that will be used for the cargo-return capsule option of Progress M. M-6 will be the first actual use of the capsule, late this year. Soviets say they now have adequate data on free-fall effects for periods of up to a year, and do not immediately plan any more very long stays. Mir crews will be up a mere six months each for the next couple of years. [For those who aren't aware of it, the US record is three months.] Mir crews in the near future will include a lot of guest cosmonauts, who will go up with a new crew and back down with the old one. This December the Japanese TV reporter will fly. Next summer's crew has the British Juno cosmonaut pencilled in, despite Juno's funding problems. The late-1991 crew will have the Austrian cosmonaut, and the mid-1992 crew the next French cosmonaut. All are paying customers. Soviets consider adding a new thruster package on an arm attached to Kvant 1. Mir could use better roll control now that heavy add-on modules are sticking out in two directions, with two more planned for late next year. Soviets use slightly modified pre-reentry procedures for Soyuz TM-9, separating both the forward orbital module and the aft service module simultaneously after retrofire. Simultaneous separation was used on early Soyuzes, and the return to it was aimed at avoiding any possible problem with the Soyuz's damaged thermal blankets. The cosmonauts report that the capsule handled perfectly on reentry. Long story on Japan's first shuttle astronaut, Mamoru Mark Mohri, now in training for the Spacelab J mission late next year. Two more Japanese shuttle astronauts are set to fly on International Microgravity Lab missions in 1993 and 1995. NASDA values these missions particularly for the flight experience they will contribute to design of the Japanese space-station module. The Japanese astronauts say they already have one problem to report with the Spacelab J hardware: it is too heavily automated, leaving little possibility of manual troubleshooting in case of difficulties. "All we can do is shut it down." They also say that NASA's post-Challenger safety-documentation requirements are excessive and are interfering with mission planning. [Lots more details on the experiments to be flown.] Details of ISAS's next two major scientific satellites: Solar A, for launch late next year, with the first solar imaging equipment to beat the capabilities of Skylab's solar telescope [from 1973], and Geotail, a solar-wind probe with very long antennas, a joint ISAS-NASA project for launch on Delta in mid-1992. [Details on experiments.] Descriptions of the Japan's next two astronomy satellites, Astro-D (1993) and Muses-B (1995). Astro-D will carry an X-ray telescope with much better sensitivity and spectral resolution than existing ones. Muses-B will be a radio observatory for VLBI work together with ground-based receivers. Both will be launched from Kagoshima, Astro-D on the last M-3S-2 and Muses-B on the first M-5. Both missions are international collaborations, with NASA supplying the X-ray telescope for Astro-D and various nations planning radio observations in conjunction with Muses-B. Both also present design challenges, with Astro-D's telescope having to telescope [!] to fit under the M-3S-2 payload fairing, and Muses-B's 10m dish presenting problems in both antenna deployment and precise attitude control of a flexible spacecraft. Story on Japanese studies, both government and commercial, for autonomous space stations, lunar bases, and advanced concepts for both launch and in-space propulsion. One project of note is work on electric propulsion for deep-space missions, notably the Jupiter probes specifically mentioned in Japan's new government space policy. -- "...the i860 is a wonderful source | Henry Spencer at U of Toronto Zoology of thesis topics." --Preston Briggs | henry@zoo.toronto.edu utzoo!henry