Jonathan's Space Report No. 425 2000 May 15 Cambridge, MA ------------------------------------------------------------------------------- Shuttle and Stations -------------------- Zalyotin and Kaleri continue their Mir mission with the Soyuz TM-30 transport and the Progress M1-2 cargo ship. On May 12 they left the station for a spacewalk. The Kvant-2 airlock hatch was opened at 1044 UTC and closed at 1536 UTC. The astronauts inspected the station and discovered burnt wiring on the Kvant solar array. Launch of STS-101 is scheduled for May 18. Compton Observatory ------------------- The Compton Gamma Ray Observatory is to be deorbited on June 3. NASA decided to end the mission because they were worried that if another gyroscope is lost, the heavy 14 tonne spacecraft might eventually reenter out of control. Although engineers came up with a way to control the descent without gyroscopes, NASA felt the risk was still too large. However, a number of scientists find the decision perverse and are urging NASA to keep the vehicle operating for now in view of the loss to science if one of the Great Observatories is abandoned. In my opinion, the decision to deorbit Compton is wrong (or at the very least, NASA has not presented Compton's users with a convincingly argued rationale), and the risks of keeping it in orbit are small, but it is unlikely that the NASA administrator will override Goddard Space Flight Center's director Al Diaz and Office of Space Science chief Ed Weiler, who made the decision. The following is extracted from a letter passed on to me by a gamma-ray astronomer - I agree with most of the points it makes, so I quote it here. "Safety is clearly and correctly a very high priority in everything that NASA does. However, it is important to have a realistic safety policy that is applied uniformly to all missions. The question is: Does continuing operation of CGRO present unacceptable risk? The risk of continuing to fly CGRO was inconsistently described at the press conference on March 24, 2000. According to the NASA officials at the press conference the decision was based upon a casualty risk of 1/1000 if another gyroscope failed, yet in response to a reporter's question those same officials confirmed a risk estimate of 1 in 4 million for a controlled reentry using zero gyroscopes." "The scientific case for continuation of the mission is beyond question. The NASA Senior Review made a strong case for continuing the CGRO Mission. The end of CGRO operations would affect virtually every sub-discipline of astrophysics. The study of gamma-ray bursts and high-energy emission from solar flares during the solar maximum period will be particularly hard-hit. With the damage suffered by the HESSI satellite during tests, loss of CGRO leaves the US with no capability for observing high-energy radiation from solar flares during the maximum of solar activity. The loss of CGRO will also be detrimental for many of the scientific objectives of presently operating and upcoming high-energy astrophysics missions, because it provides targets-of-opportunity, all-sky monitoring and coordinated observations over a very broad high-energy range. These missions include: ASCA, BeppoSAX, Chandra, INTEGRAL, HETE-2, Rossi XTE, SWIFT, and XMM-Newton. There is no spacecraft planned for the next several years that can accomplish these objectives. " On May 14, Compton was in a 482 x 487 km x 28.5 deg orbit. The observatory was launched in April 1991 on mission STS-37. Launch mass was 15622 kg (Shuttle Operational Data Book; the press kit gives 15713 kg); different sources give the hydrazine load as 1822 kg or 1920 kg, so the dry mass is at most 13800 kg. Current Launches ---------------- GOES L was launched on May 3 by Atlas Centaur AC-137. The satellite is a US civilian geostationary weather satellite in the Geostationary Operational Environmental Satellite series. It is the first GOES launch on the Atlas 2 class vehicle (the old Atlas 1 has now been phased out). GOES L will be renamed GOES 11 after it reaches geostationary orbit. GOES L was built by SS/Loral and is based on the FS-1300 bus. It has one solar panel array and a counter-boom with a solar sail. As well as an imaging radiometer, the satellite carries an X-ray detector to monitor solar activity. Kosmos-2370 was launched on May 3. It is a 17F117 Neman-class advanced imaging reconnaissance satellite derived from the TsSKB-Progress Yantar'-4KS2 design. The Neman relays digital imagery to earth via geostationary comsats and is the Russian equivalent of the KH-11. Neman was first launched in Feb 1986 (Kosmos-1731). The last Neman satellite, Kosmos-2359, reentered in Jul 1999 after 1 year in orbit. The Soyuz-U launcher placed it in a 183 x 277 km x 64.8 deg initial orbit; it raised altitude to 240 x 300 km about 24 hr after launch. Titan 4 B-29 was launched from Canaveral on May 8. The Titan 4B placed the TRW-built DSP 20 satellite in orbit with a Boeing Inertial Upper Stage, serial IUS-22. DSP 20 is an early warning satellite for the US Air Force; the two-stage IUS-22 solid rocket delivered DSP 20 to geostationary orbit. DSP 19 launched last year but was put in the wrong orbit when its IUS stage failed. This is the first fully successful Titan 4 mission from Cape Canaveral in four tries, a relief for Lockheed Martin Astronautics. Recent Titan 4 Launches Date Titan Upper Stage Payload 1997 Feb 23 4B-24 IUS-4 DSP 18 1997 Oct 15 4B-33 Centaur TC-21 Cassini/Huygens 1997 Oct 24 4A-18 None USA 133 1997 Nov 8 4A-17 Centaur TC-16 USA 136 1998 May 9 4B-25 Centaur TC-18 USA 139 1998 Aug 12 4A-20 (failed) Centaur TC-9 MERCURY ? 1999 Apr 9 4B-27 IUS-21 (failed) DSP 19 1999 Apr 30 4B-32 Centaur TC-14 (failed) Milstar 1999 May 22 4B-12 None USA 144 2000 May 8 4B-29 IUS-22 DSP 20 Another Navstar Block IIR GPS navigation satellite, GPS IIR-4 or SVN 51, was launched on May 11. The Boeing Delta II rocket placed GPS space vehicle number 51 in an elliptical transfer orbit. The GPS Block IIR satellites are built by Lockheed Martin/Sunnyvale and based on the Series 4000 comsat bus. The Thiokol Star 37 apogee motor will be used to circularize the orbit at 20000 km. Table of Recent Launches ----------------------- Date UT Name Launch Vehicle Site Mission INTL. DES. Apr 4 0501 Soyuz TM-30 Soyuz-U Baykonur LC1 Spaceship 18A Apr 17 2106 Sesat Proton Baykonur LC200L Comsat 19A Apr 19 0029 Galaxy IVR Ariane 42L Kourou ELA2 Comsat 20A Apr 25 2008 Progress M1-2 Soyuz-U Baykonur LC1 Cargo 21A May 3 0707 GOES 11 Atlas 2A Canaveral SLC36A Weather 22A May 3 1325 Kosmos-2370 Soyuz-U Baykonur LC1 Imaging 23A May 8 1601 DSP 20 Titan 4B Canaveral LC40 Early Warn 24A May 11 0148 GPS SVN 51 Delta 7925 Canaveral SLC17A Navsat 25A Current Shuttle Processing Status _________________________________ Orbiters Location Mission Launch Due OV-102 Columbia Palmdale OMDP OV-103 Discovery OPF Bay 1 STS-92 2000 Sep? ISS 3A OV-104 Atlantis LC39A STS-101 2000 May 18 ISS 2A.2a OV-105 Endeavour OPF Bay 2 STS-97 2000 Nov? ISS 4A .-------------------------------------------------------------------------. | Jonathan McDowell | phone : (617) 495-7176 | | Harvard-Smithsonian Center for | | | Astrophysics | | | 60 Garden St, MS6 | | | Cambridge MA 02138 | inter : jcm@cfa.harvard.edu | | USA | jmcdowell@cfa.harvard.edu | | | | JSR: http://hea-www.harvard.edu/~jcm/space/jsr/jsr.html | | Back issues: http://hea-www.harvard.edu/~jcm/space/jsr/back | | Subscribe/unsub: mail majordomo@head-cfa.harvard.edu, (un)subscribe jsr | '-------------------------------------------------------------------------'