The primary system for generating oxygen on the Russian space station Mir broke down last week, forcing cosmonauts to use a backup system that can supply oxygen for the next two months.
     The backup system is the same system that triggered a brief fire on the station last month that caused minor damage to the 11-year-old station.
     One of the twin Elektron units that generates oxygen from waste water on Mir failed early last week because of too much air in the system, according to reports. The second unit, activated when the first failed, was shut down on March 7 when too much hydrogen was detected.
     With both Elektron units shut down, the three men aboard Mir have turned to the backup system of lithium perchlorate cartridges, or "candles". These are normally used to supplement the primary oxygen systems when more then three people are on the station.
     On February 23, one of these canisters caused a small fire which burned for about 90 seconds before cosmonauts extinguished it. The fire did damage some hardware, but caused no injuries. Russian authorities traced the cause of the fire to a crack in the cartridge, which allowed its hot contents to leak out and trigger the fire.
      There are about 185 candles on the station, with at least 100 in good enough condition to be used. One or two of these candles will be burned each day to generate enough oxygen for the two Russians and one American on Mir.
     "You hate to see your margins reduced in any area," Frank Culbertson, who heads NASA's shuttle-Mir program, said. "Its not a comfortable situation to be in, but that's where they are right now."
     Russian engineers are working on repair plans for the Elektron units, and plan to have those plans ready by late March, when a Progress resupply craft is scheduled for launch to Mir. The resupply craft could carry any parts or tools needed to repair the units.
     The problem is the latest to hit the aging space station. Earlier last week, Russian controllers failed to dock a used Progress resupply capsule to Mir. The Progress M-33 capsule had been docked to the station since November, but was undocked earlier in the month to allow a Soyuz spacecraft carrying three cosmonauts to dock with the station.
     After several attempts to redock the capsule with Mir on March 4 failed, Russian officials decided not to try again. Instead, the capsule burned up in the Earth's atmosphere over the South Pacific east of New Zealand on March 12.
     The station can also no longer communicate with ground controllers through communications satellites in geosynchronous orbit. One Russian satellite used for communications, Altair-1, has failed, while an antenna on Mir used for communications with another satellite is no longer working.
     The Mir crew currently communicates with mission controllers via ground stations in Russia and the United States. Repair parts for the Mir antenna will be brought to the station on the next resupply mission.
     The current Mir crew includes American astronaut Jerry Linenger, who has been on the station for two months, and Russians Vasily Tsibliev and Alexander Lazutkin.
     Tsibliev and Lazutkin have been on Mir since last month. They replaced cosmonauts Valery Korzun and Alexander Kaleri, who returned to Earth with German guest cosmonaut Reinhold Ewald on March 2.

Two teams of scientists at Caltech and the University of Wisconsin have found that key structures in Martian meteorite ALH84001 formed at low enough temperatures that they could have been created by ancient life on Mars.
     The findings, announced on March 13, discount the claims of skeptics who believed that the carbonate globules found inside the ancient meteorite had to be formed at extremely high temperatures, far too hot to support life. The findings were published in the current issue of the journal Science.
     A group led by University of Wisconsin - Madison geology professor John Valley used an isotopic analysis to find that the carbonate globules must have formed at temperatures no higher than about 100 C (212 F). The study also confirmed that the globules were of Martian, and not terrestrial, origin.
     "We have not proven that this represents life on Mars, but we have disproven the high-temperature hypothesis," Valley said.
     A separate group, led by Caltech geobiology professor Joseph Kirschvink, examined the magnetic field of the meteorite. Kirschvink and his colleagues concluded the globules must have formed at low temperatures.
     "It's very pleasing to know there's other data to support our own," said Everett Gibson, one of the members of the NASA/Stanford team which made the initial announcement of past life on Mars last August. "This is really strong data."
     Other scientists had previously claimed the carbonate globules in the meteorite could only have formed at temperatures as high as 650 C (1200 F), far too high for life. The lower temperatures keep a biological origin a possibility, but other, inorganic explanations for the globules are still possible.
     The recent results and work by other researchers will be a hot topic at next week's Lunar and Planetary Science Conference in Houston. NASA has scheduled a briefing at the conference on March 19 where several scientists will announce their latest work on the Mars life question.

Russia opened a new cosmodrome in the Far East with the launch of a converted ICBM on March 4, but the launch was protested by officials of a republic within Russia.
     A Start-1 rocket launched a military satellite from the new Svobodny cosmodrome at 0200 UT on March 4. There were no problems reported with the rocket, a converted SS-25 ICBM, or the payload. The satellite, Zeya, was designed by a Russian military academy and will be used for navigation.
     The launch was the first from new facility, a former nuclear missile base, located 9,000 km (5,600 mi.) east of Moscow and only 100 km (60 mi.) from the Chinese border.
     Russian officials hope the new facility will ease some of the need to use the launch site at Baikonur, Kazakhstan. It costs Russia $115 million a year to lease the Baikonur site from the Kazakh government. However, there are no plans to move manned launches, which all currently take place at Baikonur.
     "Russia cannot be dependent on Baikonur forever and pay rent to Kazakhstan," said Pyotr Lebedev, deputy commander of Svobodny.
     Officials from the ethnic region of Yakutia, within Russia, protested the launch from Svobodny. The trajectory of the launches forces used stages to fall onto sparsely populated territory within Yakutia.
     Although a 1996 treaty between Moscow and Yakutia allowed debris from launches to fall onto Yakut territory, officials claimed they had not been properly notified of the launch. Yakut officials were considering filing suit against the Russian military and also scrapping the agreement.