Jonathan's Space Report No. 306 1996 Dec 6 Cambridge, MA ------------------------------------------------------------------------------- Shuttle and Mir --------------- When is a spacewalk not a spacewalk? In the early days of spaceflight, an EVA (extravehicular activity) had to be outside the spacecraft, and a distinction was made between SEVA (standup EVA, where you didn't entirely leave the vehicle) and a full EVA. Nowadays, NASA officially counts EVAs from the time when astronauts are on battery power. I prefer to ignore EVAs and instead log 'depress time', time spent working under vacuum conditions (with a spacesuit on, of course), since this to me is the dangerous and interesting thing. Like all the other definitions, this one is a little fuzzy. What is the distinction between a spacesuit and a spaceship? What is depressurized? Usually depressurization from near full pressure (at least 10psi, US units) to vacuum (less than 0.1psi) is pretty fast, but sometimes Shuttle astronauts stick in the airlock at around 5 psi for a while. So I try and log when they go down from about 1 psi to zero. On 1996 Nov 29, STS-80 crewmembers Tamara Jernigan and Thomas Jones were in Columbia's airlock. At 0209 UTC they depressurized, and by 0221 UTC the airlock was fully depressurized. However, the astronauts were unable to open the airlock due to a stuck handle. At 0307 UTC, the airlock was partially repressurized to 4psi, and the airlock thermal cover was blown off for inspection. After further fruitless attempts to open the hatch, full repressurization began at 0348 and was complete at 0401, with the astronauts still in their suits. Story Musgrave came in without a suit and again tried to free the hatch - this sounds scary, but interal pressure in the airlock would have prevented a leak if he had succeeded. NASA does not count this as an EVA, since at no time did the astronauts go to battery power. But I log this as a depress phase, with the astronauts getting 0h46min of depress time. After thinking hard for a couple of days, NASA decided to cancel any further attempts at spacewalks on this mission. There are cases where a contingency EVA (emergency spacewalk) would be necessary, for instance if the payload bay doors refused to close. They would try and force the hatch open in that case. At this writing, the doors were closed and opened again on Dec 5, closed on Dec 6 and due to open again, following reentry attempts on Dec 5 and Dec 6 which were called off due to bad weather. On Dec 3, Columbia began its re-rendezvous with the ORFEUS-SPAS astronomy satellite. On Dec 4 at 0823 UTC, the astronauts retrieved the ORFEUS-SPAS vehicle using the RMS arm. Landing is now scheduled for Dec 7, making STS-80 the longest shuttle mission so far at almost 18 days. Aboard Mir, Valeriy Korzun, Aleksandr Kaleri and John Blaha are unloading the Progress M-33 transport ship. On Dec 2 Korzun and Kaleri made a 5h 57min space walk to install a new solar panel. They opened the Kvant-2 hatch at 1554 UTC (no stuck hatches here!). Blaha remained aboard the station. Recent Launches --------------- Mars-96, continued: Jim Oberg reports that US Space Command now thinks it detected the reentry of Mars-96 over the eastern Pacific and South America, and eyewitness reports from the Atacama Desert indicate that Mars-96 hit the ground somewhere in northern Chile or Bolivia, far from the Blok-D-2 impact point the following day (where all the air searching was done). At least three groups of witnesses in northern Chile, including a former European Southern Observatory staff member, report seeing a bright object breaking apart and changing colors at 0050 UTC on Nov 17, consistent with the reentry time of Mars-96. Although this evening coincided with the Leonid meteor shower, the time of night and the speed and direction of the object rule out the possiblity of a large Leonid-related meteorite. (Thanks to Jorge Ianisewski and Mike Keane for passing on the eyewitness reports.) NASA's Mars Pathfinder (MPF) space probe was successfully launched on Dec 4 from Cape Canaveral. Pathfinder will land in Ares Vallis on 1997 Jul 4. The space probe consists of a cruise stage, an atmospheric entry aeroshell, a lander, and the tiny Sojourner rover which will use an x-ray spectrometer to study the composition of Martian rocks near the landing site. The McDonnell Douglas Delta 7925 rocket took off from Launch Complex 17B, and the second stage and payload entered a 28 degree inclination elliptical earth parking orbit. The second stage ignited again an hour after launch to raise orbit, followed immediately by the third stage which propelled MPF into solar orbit. After its depletion burn, the second stage ended up in a 148 x 3119 km x 36.4 deg orbit. MPF was originally part of the MESUR Mars Environmental Survey; that program was abandoned and MPF became one of the Discovery series of planetary missions (like the NEAR asteroid probe). The companion MGS probe launched on Nov 7 is a Mars Surveyor, which is technically a separate NASA program. Table of Recent Launches ------------------------ Date UT Name Launch Vehicle Site Mission INTL. DES. Oct 20 0720 FSW-2 Chang Zheng 2D Jiuquan Remote sen. 59A Oct 24 1137 Molniya-3 Molniya-M Plesetsk Comsat 60A Nov 4 1709 SAC-B/HETE Pegasus XL Wallops Science 61A Nov 7 1700 MGS Delta 7925 Canaveral LC17A Mars probe 62A Nov 13 2240 Arabsat 2B ) Ariane 44L Kourou ELA2 Comsat 63A Measat 2 ) Comsat 63B Nov 16 2048 Mars-96 Proton-K Baykonur LC200L Mars probe 64A Nov 19 1955 Columbia Shuttle Kennedy LC39B Spaceship 65A Nov 19 2320 Progress M-33 Soyuz-U Baykonir LC1 Cargo ship 66A Nov 20 0411 ORFEUS OV-102,LEO Astronomy 65B Nov 21 2047 Hot Bird 2 Atlas IIA Canaveral LC36B Comsat 67A Nov 22 2038 WSF OV-102, LEO Materials 65C Dec 4 0658 Mars Pathfinder Delta 7925 Canaveral LC17B Mars probe 68A Current Shuttle Processing Status ____________________________________________ Orbiters Location Mission Launch Due OV-102 Columbia LEO STS-80 OV-103 Discovery OPF Bay 2 STS-82 Feb 13 OV-104 Atlantis OPF Bay 3 STS-81 Jan 12 OV-105 Endeavour Palmdale OMDP ML/SRB/ET/OV stacks ML1/RSRM-58/ VAB Bay 3 STS-82 ML2/RSRM-54/ET-83 VAB Bay 1 STS-81 ML3/ .-------------------------------------------------------------------------. | Jonathan McDowell | phone : (617) 495-7176 | | Harvard-Smithsonian Center for | | | Astrophysics | | | 60 Garden St, MS6 | | | Cambridge MA 02138 | inter : jcm@urania.harvard.edu | | USA | jmcdowell@cfa.harvard.edu | | | | JSR: http://hea-www.harvard.edu/QEDT/jcm/space/jsr/jsr.html | | Back issues: ftp://sao-ftp.harvard.edu/pub/jcm/space/news/news.* | '-------------------------------------------------------------------------'