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