I'm now getting some info "straight from the horse's mouth." I'm not yet sure how this information will impact the ISS TLEs posted on the SVPOST.html page (which I use to generate ISS transit goodies), but it does indicate the current orientation of the ISS, which can be fed into Mike Tyrrell and Phil Masding's ISS VRML simulator, to help with the interpretation of any video you may capture. This information "should not be used for precise applications or analysis" ... whatever that means ;-) Oddly enough, I also recently received information from the MCC that the MCC TLEs are based upon a True Equator / Mean Equinox (TEME) reference frame, while analysis of the simultaneous ISS / Venus transit suggested that they are referenced to MEME, while OIG TLEs are referenced to TETE: http://www.satobs.org/seesat/Aug-2004/0111.html However below, associated with what I assume is the raw data for the orbit determination vectors, it states: X axis = mean vernal equinox of epoch Z axis = earth mean rotation axis of epoch * Daily solar flux is predicted to be around 113 over the next 3 days. * Daily earth geomagnetic activity is predicted to be predominantly at quiet to unsettled levels over the next 3 days. There is the possibility for isolated active periods on prediction days 2 and 3. * ISS is scheduled to perform a orbit adjust-phasing maneuver early tomorrow UTC time. The current burn time is 233:01:24:30 UTC and the maneuver delta-v is 1.3 meters/second. An updated orbital elements file will be sent out when a post-track vector becomes available. * ISS maneuvered to LVLH attitude mode at approximabely 232:01:14:00 UTC. The following on-orbit vector is provided by NASA Johnson Space Center Flight Design and Dynamics Division for use in ground track plotting programs. It should not be used for precise applications or analysis! Data were generated using application SPCM V4.0 DLL Vehicle = Current ISS Lift off time (UTC) : 2004/232:11:17:52.0000 Vector time (UTC) : 2004/232:11:17:52.0000 Vector time (MET) : + 0: 0: 0: 0.0000 Orbit : 825 Weight (lbs) : 404131.10 Area (sq ft) : 5000.00 Drag Coefficient (Cd) : 2.00 90 day mean solar flux (jansky) : 108.00 12 month mean earth geomagnetic index : 2.79 This vector is valid for prediction purposes until 234: 0: 0: .0 UTC M50 Cartesian M50 Keplerian ------------------------------ ------------------------------ X = 6723456.17 A = 6740465.06 meter Y = -80690.92 meter E = .0012810 Z = -429248.36 I = 51.66368 XDOT = 432.022909 Wp = 66.22722 YDOT = 4776.778056 meter/sec RA = 2.20607 deg ZDOT = 6015.067180 TA = 289.11397 MA = 289.25263 Ha = 200.294 n.mi Hp = 190.969 M50 Cartesian J2K Cartesian ------------------------------ ------------------------------ X = 22058583.23 X = 6725944.44 Y = -264733.99 feet Y = -5496.00 meter Z = -1408295.14 Z = -396571.80 XDOT = 1417.397995 XDOT = 349.352103 YDOT = 15671.844016 feet/sec YDOT = 4781.146707 meter/sec ZDOT = 19734.472375 ZDOT = 6016.965584 M5O = Inertial mean of year 1950 frame of reference Epoch = beginning of Besselian year 1950 X axis = mean vernal equinox of epoch Z axis = earth mean rotation axis of epoch Y axis = completes right handed cartesian earth centered system J2K = Inertial mean of year 2000 frame of reference Epoch = Julian date 2451545.0 TDT X axis = mean vernal equinox of epoch Z axis = earth mean rotation axis of epoch Y axis = completes right handed cartesian earth centered system The mean element set is posted at a UTC for which position is just north of the next ascending node relative to the above vector time USSPACECOM TWO LINE MEAN ELEMENT SET ISS 1 25544U 98067A 04232.47149943 .00017467 00000-0 13994-3 0 9547 2 25544 51.6329 2.6661 0005330 129.3272 230.8362 15.71066323 8260 Satellite: ISS Catalog number: 25544 Epoch time: 04232.47149943 = yrday.fracday Element set: 954 Inclination: 51.6329 deg RA of node: 2.6661 deg Eccentricity: .0005330 Arg of perigee: 129.3272 deg Mean anomaly: 230.8362 deg Mean motion: 15.71066323 rev/day Decay rate: 1.74670E-04 rev/day^2 Epoch rev: 826 Checksum: 280 ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Thu Aug 19 2004 - 12:04:25 EDT