Gene Harriman wrote: > I saw Kevin F.'s note on the ISS orbit boost, and I'm looking > at the NASA page referenced. I see the part at the top where > maneuvers are referenced. Can someone help me with what I'm > looking at? > That is, what do the various parts mean? > > IMPULSIVE TIG (GMT) M50 DVx(FPS) LVLH DVx(FPS) DVmag(FPS) > IMPULSIVE TIG (MET) M50 DVy(FPS) LVLH DVy(FPS) Invar Sph HA > DT M50 DVz(FPS) LVLH DVz(FPS) Invar Sph HP > > ------------------------------------------------------------------------ > 171/06:52:31.233 9.6 11.3 11.4 > N/A -3.1 0.1 186.8 > 000/00:19:02.466 -5.1 0.2 186.2 The first column state the day and the time of the manoeuvre, as GMT and mission-elapsed time (MET). The middle two columns state the Cartesian components of the velocity change in feet per second; the first in an Earth-centred inertial frame, the second in the vehicle's Local Vertical Local Horizontal rotating, instantaneously inertial frame. The final column states the magnitude of the velocity change in feet per second, and the resulting apogee and perigee height, in nautical miles. Additional information on the coordinate systems is available here: http://spaceflight1.nasa.gov/realdata/elements/index.html To generate predictions that take into account the manoeuvre, look up the elements for the first coasting arc after the time of ignition; in this case, coasting arc #4, as appended to this message. The elements are stated in several forms, but the most commonly used are the 2-line mean elements, which are listed last. Ted Molczan Coasting Arc #4 (Orbit 2885) --------------------------------------- Vector Time (GMT): 2008/171/07:02:02.466 Vector Time (MET): N/A Weight (LBS) : 661038.9 M50 Cartesian M50 Keplerian ----------------------------------- -------------------------------- X = 592665.98 A = 6718465.15 meter Y = -4132509.24 meter E = .0005618 Z = -5268729.42 I = 51.64927 XDOT = 7649.903609 Wp = 88.16827 YDOT = 836.463568 meter/sec RA = 5.03357 deg ZDOT = 204.804353 TA = 183.77368 MA = 183.77792 Ha = 186.838 n.mi Hp = 186.165 M50 Cartesian J2K Cartesian ----------------------------------- -------------------------------- X = 1944442.19 X = 664426.78 Y = -13558101.20 feet Y = -4125479.33 meter Z = -17285857.68 Z = -5265676.85 XDOT = 25098.108954 XDOT = 7638.986683 YDOT = 2744.303045 feet/sec YDOT = 921.948085 meter/sec ZDOT = 671.930291 ZDOT = 241.941191 TDR Cartesian TDR Cartesian ----------------------------------- -------------------------------- X = -973289.49 X = -296658.64 Y = -13676663.91 feet Y = -4168647.16 meter Z = -17274414.93 Z = -5265241.67 XDOT = 24088.932026 XDOT = 7342.306482 YDOT = -2742.140976 feet/sec YDOT = -835.804569 meter/sec ZDOT = 814.988173 ZDOT = 248.408395 The mean element set is posted at the UTC for which position is just north of the next ascending node relative to the above vector time TWO LINE MEAN ELEMENT SET ISS 1 25544U 98067A 08171.30853553 .00020000 00000-0 20000-3 0 9031 2 25544 51.6413 5.4475 0009429 273.9651 86.0434 15.74579497 28861 Ted Molczan ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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