Jonathan's Space Report<br />No. 524 2004 Apr 23, Somerville, MA<br />----------------------------------------------------------------------------<br />---<br /><br />Space Station Expedition 9 has begun with the Apr 19 launch of Soyuz TMA<br />spacecraft 11F732 No. 214, designated Soyuz TMA-4. Soyuz TMA-4 is<br />transport mission ISS 8S and delivers the Expedition 9 crew of<br />Gennadiy Padalka and Michael Fincke, together with the ESA/Netherlands<br />DELTA mission crewmember Andre Kuipers, to the Space Station. The Dutch<br />astronaut will return to Earth with the Expedition 8 crew of Michael<br />Foale and Aleksandr Kaleri on Soyuz TMA-3, leaving Expedition 9 in<br />charge of the station. Soyuz TMA-4 docked with the nadir port on Zarya<br />at 0501 UTC on Apr 21 and the hatches to the ISS were opened at 0630<br />UTC. Meanwhile, another gyro on the station has shut down and may<br />require a maintenance spacewalk to replace its failed electronics box.<br /><br />NASA's Gravity Probe B satellite was finally launched on 2004 Apr 20<br />after 40 years of development. The 3145 kg spacecraft carries 4<br />gyroscopes kept at 1.8 Kelvin by a liquid helium dewar, laser<br />retroreflectors and 2 GPS receivers for orbit determination, a drag<br />compensation system, and a 14 cm aperture quartz telescope. The<br />challenging physics experiment, developed by Stanford University<br />together with Lockheed Martin, will observe the 5th magnitude star IM<br />Peg for over a year, attempting to measure the tiny shifts in the<br />gyroscopes' orientation caused by the Lense-Thirring gravitomagnetic<br />(or `frame-dragging') effect predicted by general relativity. The<br />frame-dragging caused by the Earth's rotation will make the orbital<br />plane rotate by 40.9 millarcseconds per year. GP-B's polar orbital<br />inclination of 90.01 degrees was chosen to minimize the orbital plane<br />rotation due to the Newtonian effect of the Earth's polar flattening,<br />which is proportional to the cosine of the inclination. GP-B will also<br />make an accurate measurement of the well-established gravitostatic<br />warping of spacetime due to the Earth's mass, which is a much larger<br />effect of 6.6 arcseconds per year in a perpendicular (in-plane) direction.<br /><br />One way of thinking about the gravitomagnetic effect is as a kind of<br />antigravity, in that it decreases the gravitational attraction between<br />two moving masses. Like electromagnetism, it is always smaller (by<br />powers of v/c) than the static gravitational attraction. In<br />electromagnetism, however, the static effect can be (and usually is)<br />cancelled out by having equal amounts of positive and negative electric<br />charges, and so the small relativity effect between moving charges that<br />we call "magnetism" becomes dominant and indeed familiar. Because there<br />are no negative gravitational charges (even antimatter particles have<br />positive mass) this never happens with gravity, ensuring that the<br />antigravity, moving-masses, Lense-Thirring effect is always much less<br />than the normal positive gravity generated by the same masses, and thus<br />doesn't do starship inventors any good. [Warning: I am not a real<br />relativist: there are probably egregious errors in the above<br />description.]<br /><br />In Newtonian physics when a satellite orbits a spherical planet the<br />orbital plane of the satellite `stays put' and the planet `turns<br />underneath it'. It doesn't matter whether or not the planet is rotating.<br />The effect of relativistic frame dragging is to change the meaning of<br />`stays put', rotating the path of a locally freely falling object near<br />the planet with respect to the distant universe. We think of the gravity<br />of the rotating planet dragging spacetime around with it. For a<br />non-polar orbit, it becomes easier to orbit in the direction of rotation<br />than against it, with the equivalent of Kepler's third law becoming<br />inclination-dependent - in some sense a prograde orbit has a lower<br />orbital velocity than a retrograde orbit of the same height, because the<br />mass pulls it around for free. Around a rotating black hole, this effect<br />becomes huge, and the last stable prograde orbit is much closer in than<br />the last stable retrograde orbit.<br /><br />The Delta 7920 rocket entered a 167 x 652 km transfer orbit and then<br />fired again to put GP-B in a 641 x 645 km x 90.01 deg orbit. The second<br />stage then separated and two further burns put it in a 182 x 631 km x<br />94.56 deg orbit to ensure that it would not recontact GP-B and that it<br />will reenter rapidly.<br /><br />China launched two small satellites from its low-latitude Xichang launch<br />site on Apr 18 into a 599 x 615 km x 97.7 deg polar orbit. This was the<br />first polar launch from Xichang; previous Chinese sun-synchronous<br />missions were from Taiyuan. Shiyan 1 ('Experiment') is a 204 kg<br />microsatellite developed by the Harbin Institute of Technology, with a<br />stereo imager to carry out land resource mapping. Naxing 1 (a<br />contraction of Nami Weixing 'Nanosatellite') is an experimental vehicle<br />with mass under 25 kg to test small satellite technology and was<br />developed by Tsinghua University in Beijing. Pictures of the launch show<br />a fairing similar to the one used for the CZ-2C/SD but given the low<br />total mass of the payloads I'm assuming that no upper stage was used and<br />that the CZ-2C second stage entered orbit; payload deployment was 12 min<br />after launch. Four objects have been cataloged: two objects in the 599 x<br />615 km orbit are probably Shiyan-1 and Naxing 1, while a third object in<br />a 543 x 619 km orbit is believed by visual observers to be the second<br />stage. Seven debris objects have been cataloged, of which four are<br />probably the second stage separation motor covers. 2004-14D is in a much<br />lower perigee orbit of 350 x 606 km x 97 deg and may have separated<br />prior to second stage vernier cutoff. (It's also possible that 14D is<br />the second stage, and 14C is a third stage insertion motor; at the<br />moment I think this is less likely.)<br /><br />A Lockheed Martin Atlas IIAS, serial AC-163, was launched on Apr 16 into<br />a 150 x 396 km parking orbit and then restarted to reach a 167 x 122343<br />km x 26.3 deg highly elliptical orbit. It delivered to orbit the<br />Superbird 6 satellite, a Boeing BSS-601 model which will provide Ka and<br />Ku band communications for Japan's Space Communications Corp. with the<br />operational name of Superbird A2. The high apogee orbit will allow<br />Superbird 6 to lower its inclination to equatorial with a minimum usage<br />of fuel, and only then lower its orbital height to the 35780 km<br />geostationary altitude. Once again, Space Command took a long time to<br />issue orbital data; the first elset was issued on Apr 21, giving an<br />orbit of 1137 x 120678 km x 25.48 deg following the initial apogee<br />burns.<br /><br />The Briz from the Eutelsat launch and the Blok DM from the Kosmos-2406<br />launch have still not been tracked; I gather that Space Command has<br />fewer deep space sensors than it used to, due to budget cuts. Given the<br />increasing importance of deep space `situational awareness', I assume<br />this suprising lack of US capability will be remedied fairly soon.<br />Kosmos-2406 is now being tracked in geostationary orbit at 85.0E.<br />Eutelsat W3A is on station at 1.8E.<br /><br />The Scaled Composites rocket-powered Spaceship One made its second<br />powered flight on Apr 8 to an altitude of 32 km. This altitude has<br />previously been exceeded on a piloted flight by the Ross-Prather 1961<br />balloon flight, one Ye-66 (modified MiG-21) and two Ye-266 (modified<br />MiG-25) jet flights, several NF-104A Starfighter flights, one X-2<br />flight, many flights of the X-15 rocketplanes, and of course all<br />spaceflights. Once the Scaled team reaches 37 km it will be closer to<br />record territory: the highest non-X-15 piloted flights I am aware of<br />were Aleksandr Fedotov's 37.7 km MiG E-266M flight on 1977 Aug 31 and<br />Iven Kincheloe's 38.5 km X-2 flight on 1956 Sep 7. There were 70 flights<br />of the X-15 higher than that.<br /><br />Table of Recent Launches<br />-----------------------<br /><br />Date UT Name Launch Vehicle Site Mission<br />INTL.<br /><br />DES.<br />Mar 2 0717 Rosetta Ariane 5G+ Kourou ELA3 Comet probe<br />06A<br />Mar 13 0540 MBSAT Atlas IIIA Canaveral SLC36B Comms<br />07A<br />Mar 15 2306 Eutelsat W3A Proton-M/Briz-M Baykonur PL81 Comms<br />08A<br />Mar 20 1753 Navstar SVN 59 Delta 7925 Canaveral SLC17B Navigation<br />09A<br />Mar 27 0330 Kosmos-2406 Proton-K/DM-2? Baykonur PL81 Comms<br />10A<br />Apr 16 0045 Superbird 6 Atlas IIAS Canaveral SLC36A Comms<br />11A<br />Apr 18 1559 Shiyan 1 ) CZ-2C Xichang Imaging<br />12A<br /> Naxing 1 ) Tech<br />12<br />Apr 19 0319 Soyuz TMA-4 Soyuz-FG Baykonur LC1 Spaceship<br />13A<br />Apr 20 1657 Gravity Probe B Delta 7920 Vandenberg SLC2W Science<br />14A<br /><br />.-------------------------------------------------------------------------.<br />| Jonathan McDowell | phone : (617) 495-7176 |<br />| Somerville MA 02143 | inter : jcm@host.planet4589.org |<br />| USA | jcm@cfa.harvard.edu |<br />|<br /> |<br />| JSR: http://www.planet4589.org/jsr.html<br /><br /><br />--<br />---------------------------