Jonathan's Space Report No. 404 1999 Jul 25 Cambridge, MA ------------------------------------------------------------------------------- STS-93/Chandra --------------- LAUNCH! Chandra is in transfer orbit and is sending data back to Cambridge. A beautiful launch with some scary moments. And a wonderful trip to the Cape, it was great to finally meet so many of you that I've corresponded with. I set out from my hotel in Cocoa Beach on Monday afternoon. South of the Cape itself, there's a thin peninsula with the towns of Cape Canaveral and Cocoa Beach, and the Cape's administrative HQ at Patrick AFB. Driving up A1A from Cocoa Beach, you pass United Space Alliance's Shuttle Logistics Depot, in a building which looks to me like a car dealership. Passing the turnoff for Cape Canaveral Air Station, I drove on across the Banana River to Merritt Island, and north on State Road 3, stopping off at Space Shirts to get my required STS-93 t-shirts and patches. At the gate to KSC, it's still many miles to Complex 39. The VAB looms large, and seems to stay the same size for ages, but eventually I arrive. It's an immense building. Yes, I knew this, but the reality is impressive. Across the road from the VAB is the LC39 press site, with the famous countdown clock you've all seen on TV. The clock sits by the water's edge at the end of a grassy field, behind which are the viewing stand and the NASA newsroom. Next to the newsroom are the buildings for CBS, ABC, etc. and the trucks for the smaller local TV stations. TRW's hospitality tent was at the bottom of the field next to the clock. The first launch attempt was on Jul 20, and controllers commanded an RSLS hold at T-6 seconds, just moments before main engine ignition. A data spike in hydrogen pressure data was the problem; if it had really been an indication that there was lots of hydrogen leaking into the engine compartment, there would be danger of explosion, so the cutoff was a good idea. Second try was Jul 22. Everything looked good except for one weather system which was moving south out of the area. Fine, we'd still get off within the 46 minute window. Then we saw a lightning flash. As the hold wore on, the storm continued. It was dry at the LC39 press site, but we kept seeing flashes and hearing thunderclaps in the distance. It became clear that the chances of going that night were not good. Jul 23 was the charm. Launch was at 0431:00 UTC from LC39B at Kennedy Space Center. 5 seconds after launch, a short in an electrical bus brought down a main engine controller on two of the main engines. There are three buses, each supplying two main engine controllers. There are six engine controllers, two for each main engine, and the two controllers for each engine always run off different buses. So after the short, there was still at least one controller working on each engine. If there had been a similar short in a second electrical bus, then one of the main engines would have had no working controllers, which would have resulted in the engine shutting down. That early in the ascent, we'd have had the first ever attempt at an RTLS (Return To Launch Site) abort. So to hear comm traffic about bad engine controllers as Columbia was still streaking over the countdown clock was rather alarming. Happily, the short was not repeated and the remainder of the ascent seemed solid (but see below). The main thing that surprised me was the intense collimated exhaust from the SRBs. In all of the photos I've seen, the exhaust is so overexposed that there's no sign of this: in the middle of the broader bright smoke, there were twin narrow columns of eyeball-searing, actinic, magnesium-flare-like emission, as if a pair of cracks had opened in spacetime to let a bit of the primordial fireball peek through. I don't remember seeing this from the STS-37 daytime launch, but I was further away for that one. The other thing was the noise. The loud rumble of the SSME ignition reached us a few seconds after launch, and was then overwhelmed by the remarkable crackling and popping noise that I assume was the SRBs. The Ariane launch I saw last year had a similar quality to it, and again I've never heard it sound like this on TV broadcasts. We were just able to follow SRB separation through the haze, and the SSMEs were visible until about 5 minutes into the flight. Main engine cutoff (MECO) was at 0439 UTC, and the external tank separated leaving Columbia in a 78 x 276 km x 28.5 deg transfer orbit. The engines cut off slightly early when the LOX supply ran out (about 1700 kg short), leaving Columbia short of speed by 5 meters/s. NASA now believes that engine no. 3 had a small hydrogen leak throughout the ascent, causing the engine to run hot. The OMS-2 engine burn at 0512 UTC circularized the orbit, about 10 km lower than planned. At around 1000 UTC the IUS ASE tilt table was raised 29 degrees out of the payload bay, and the Chandra lower antenna was tested. At 1142 UTC the IUS ASE was raised to 58 degrees, the deployment angle. Chandra/IUS-27 was deployed from Columbia at 1147 UTC Jul 23. At 1248 UTC the IUS-27 SRM-1 motor fired for 125s to enter a 226 x 13841 km x 28.5 deg orbit. The SRM-1 then separated (it appears that a second object may also be being tracked in this orbit) and SRM-2 fired at 1251 UTC for 117 seconds. Chandra then deployed its solar arrays at 1322 UTC, and SRM-2 separated from Chandra at 1350 UTC. Chandra was placed in a 330 x 72030 km x 28.45 deg orbit. This was about 900 km lower than planned, the IUS underperformed slightly, but Chandra's own IPS propulsion system will make up most of the difference. The ACIS and HRC cameras have been switched on and both are operating well, although we won't open the lid to see the sky till mid-August. Chandra Orbit data: (thanks to Ted Molczan for putting them in 2-line format) Pre IPS-1 (actual) 1 25867U 99040 B 99204.57559028 .00000000 00000-0 00000-0 0 08 2 25867 28.4528 196.2671 8423730 270.0155 14.5069 0.98883441 08 Post IPS-1 (expected) 1 25867U 99040 B 99206.05309028 .00000000 00000-0 00000-0 0 06 2 25867 28.4448 196.0098 8237110 270.3411 180.5498 0.97397854 00 Post IPS-1 (Space Command) 1 25867U 99040B 99206.05347222 -.00000025 00000-0 00000+0 0 78 2 25867 28.4406 196.0256 8242614 270.3420 180.3395 0.97337724 32 At 0111 UTC on Jul 25 we fired the IPS engines for 5 minutes to raise perigee to 1192 km. The IPS engineer was very happy! The burn went well and the vehicle was extremely stable. We are waiting for DSN to measure the new orbit. Further burns will raise orbit further to 10000 km x 140000 km. TRW's IPS propulsion system is a dual-mode system, with O2/hydrazine for the four main 450N IPS engines, and mono hydrazine for the RCS system. There's also a small momentum dumping hydrazine system that is used throughout the mission for attitude control when the momentum wheels get saturated. Any extra hydrazine left over when the O2 runs out will be transferred to that system. Chandra is the heaviest Shuttle payload yet. It's hard to do the bookkeeping, because total cargo masses aren't easy to come by, they usually just release 'payload chargeable weight', and orbit insertion mass is harder to find than the less interesting launch mass. But, for what it's worth, my best estimates for the heaviest Shuttle flights are: - Launch mass of orbiter STS-93 (Chandra) 122534 kg STS51L (TDRS 2) 121530 kg (failed to orbit) STS-41D (PAM) 119576 kg STS-51A (PAM) 119454 kg STS-90 Neurolab 119003 kg Total cargo mass STS-93 (Chandra) 25700 kg approx? STS51L (TDRS 2) 23884 kg STS-41 (ULS) 22665 kg STS-43 (TDRS 5) 22373 STS-54 (TDRS 6) 22244 Mass of deployed payload: Chandra/IUS-27 19736 kg (planned) Magellan/IUS-18 18197 kg Ulysses/IUS-17 17510 kg USA-8/IUS-11 17400 kg? (estimate) USA-48/IUS-5 17400 kg? (estimate) Galileo/IUS-19 17383 kg TDRS-7/IUS-26 17107 kg TDRS-4/IUS-9 17073 kg TDRS-B/IUS-3 17071 kg (not deployed, launch failure) DSP-16/IUS-14 17050 kg TDRS-5/IUS-15 17044 kg TDRS-1/IUS-1 17030 kg TDRS-3/IUS-7 17016 kg TDRS-6/IUS-13 17008 kg DSCS/IUS-12 17000 kg? (estimate) The IUS has been used on 15 Shuttle flights. The IUS itself is not reusable, but the tilt table and airborne support equipment (ASE) is; there have been three IUS ASEs flown. ASE-1 made only two flights, on STS-6 and on 51-L when it was destroyed. ASE-2 made 7 flights, and ASE-3, built to replace the lost ASE-1, has made 6 flights if as I suspect it was used on the current mission (haven't managed to confirm this). The previous flights of ASE-3 are believed to be STS-30 (Magellan), STS-33R, STS-43 (TDRS 5), STS-54 (TDRS 6) and STS-70 (TDRS 7). There have been a number of other RSLS holds in the STS program: 1984 Jun 26 41-D RSLS abort T-6s 1985 Jul 12 51-F RSLS abort T-3s 1985 Dec 18 61-C RSLS hold T-14s 1993 Mar 22 STS-55 RSLS abort T-3s 1993 Apr 6 STS-56 RSLS hold T-11s 1993 Jul 24 STS-51 RSLS hold T-19s 1993 Aug 12 STS-51 RSLS abort T-3s 1994 Aug 18 STS-58 RSLS abort T-2s 1998 Dec 3 STS-88 RSLS hold T-19s 1999 Jul 20 STS-93 RSLS hold T-6s Recent Launches --------------- The Progress M-42 cargo ship was launched Jul 16. It is bringing supplies to the crew of the Mir complex. Progress M-42 docked with the Kvant port at 1753 UTC on Jul 18. Progress M-41 undocked at 1120 UTC on Jul 17 and was deorbited over the Pacific later the same day. Viktor Afanas'ev and Sergey Avdeev made a spacewalk on Jul 23 at 1106 UTC for about 6 hours (no confirmed duration yet). They installed a new antenna but failed to deploy it. Jean-Pierre Haignere remained inside Mir during the EVA. An Okean-O remote sensing satellite was launched by a Zenit-2 from Baykonur on Jul 17. This is the first of a new generation of larger Okean oceanographic satellites, with a mass of about 6500 kg. It was placed in a sun-synchronous 661 x 662 km x 98.0 deg orbit. The satellite carries a side-looking radar (RSL-BO), and a set of visible and infrared scanners and radiometers. It is built by the Ukranian Yuzhnoe company and is a joint project of the Russian Aviation/Space Agency (RAKA) and the Ukrainian National Space Agency (NKAU). Four more Globalstar satellites were launched Jul 25 by a Boeing Delta 2. The Delta 2 second stage entered a 185 x 1361 km transfer orbit 11 minutes after launch. At 61 min after launch the second stage restarted at apogee and deployed the four satellites in a 1367 km circular orbit. Meanwhile the four Globalstars launched on Jul 10 are already in their 1410 x 1414 km x 52.0 deg operational orbits. Table of Recent Launches ----------------------- Date UT Name Launch Vehicle Site Mission INTL. DES. Jun 5 0721 Starshine - OV-103, LEO Education 30B Jun 10 1348 Globalstar 52) Delta 7420-10 Canaveral SLC17B Comsat 31A Globalstar 49) 31B Globalstar 25) 31C Globalstar 47) 31D Jun 11 1715 Iridium 14A ) CZ-2C/SD Taiyuan Comsat 32A Iridium 21A ) Comsat 32B Jun 18 0149 Astra 1H Proton-K/DM3 Baykonur LC81L Comsat 33A Jun 20 0215 QuikScat Titan 23G Vandenberg SLC4W R/Sensing 34A Jun 24 1544 FUSE Delta 7320-10 Canaveral SLC17A Astronomy 35A Jul 5 1332 Raduga Proton-K/BrizM Baykonur LC81P Comsat F02 Jul 8 0846 Molniya-3 Molniya-M Plesetsk Comsat 36A Jul 10 0845 Globalstar 32) Delta 7420-10 Canaveral SLC17B Comsat 37A Globalstar 30) Comsat 37B Globalstar 35) Comsat 37C Globalstar 51) Comsat 37D Jul 16 1636 Progress M-42 Soyuz-U Baykonur LC1 Cargo 38A Jul 17 0638 Okean-O Zenit-2 Baykonur LC45 R/Sensing 39A Jul 23 0428 Columbia Shuttle Kennedy LC39B Spaceship 40A Jul 23 1147 Chandra IUS OV-102, LEO Astronomy 40B Jul 25 0746 Globalstar 26) Delta 7420-10 Canaveral SLC17A Comsat 41A Globalstar 28) Comsat 41B Globalstar 43) Comsat 41C Globalstar 48) Comsat 41D Current Shuttle Processing Status _________________________________ Orbiters Location Mission Launch Due OV-102 Columbia LEO STS-93 Jul 20 OV-103 Discovery OPF Bay 1 STS-103 Oct 14 OV-104 Atlantis OPF Bay 3 STS-101 Dec 2 OV-105 Endeavour OPF Bay 2 STS-99 Sep 18 MLP1/ LC39B STS-93 MLP2/ MLP3/RSRM-71? VAB Bay 3 STS-99 .-------------------------------------------------------------------------. | 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 | '-------------------------------------------------------------------------'

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