Titan IV B-30 is scheduled to lift-off on 2005 Apr 30 at 00:50 UTC (Apr 29 at 20:50 EDT). The duration of the window has not been announced. I have cooked up trajectory data to aid in observing the rocket's ascent up the east coast of North America. Rocket scientists likely would have a good laugh at my estimates, but I hope that they will be sufficient to provide a rough idea of when and where to look. Users of Rob Matson's Skymap program, should copy the appended data into a *.trj file. Non-Skymap users, can download an Excel spreadsheet to compute azimuth and elevation during the ascent to orbit: http://satobs.org/seesat_ref/B-30/Titan_IV_B-30_look_angles.xls All you need do is enter the lift-off time, and your latitude and longitude. As downloaded, the file contains the latitude and longitude of Washington, D.C., which you should replace with your latitude and longitude. The spreadsheet computes azimuth and elevation at 10 s time intervals. Azimuth is in degrees, clockwise from due north. Elevation is in degrees above the horizon. Negative values of elevation indicate that the vehicle is below the horizon. The trajectory data begins at T+2:30, about the time that the solid rocket motors burn out. Observers who have seen shuttle night-time ascents along the east coast, should not expect the Titan IV's exhaust to be as bright. For about 3 min after SRB burnout, the T-IVB's 1st stage will produce about 550,000 pounds of thrust - about one third the total output of a shuttle's main engines. The T-IVB's 2nd stage ignites for nearly 4 min; however, it produces a little over 100,000 pounds of thrust - about 7 percent the total output of a shuttle's main engines. Assuming lift-off occurs near the scheduled time, the vehicle may be illuminated by sunlight for some portion of its ascent, which should make it easy to spot with the unaided eye. It could reach magnitude 1 or brighter. I estimate that it will climb out of Earth's shadow at about T+3:30. How long it remains in sunlight depends on how high it climbs. Since its trajectory and planned orbit are secret, I can only guess. I based the ascent trajectory on one of several possible target orbits, specifically, that of a Lacrosse radar imaging satellite, inclined 57 deg, and 425 X 671 km. An ascent trajectory bound for that orbit, would remain illuminated throughout the powered ascent, after exiting the shadow at about T+3:30. In the event that the target orbit is much lower, then the vehicle may re-enter the shadow before the end of the powered ascent, in which case the vehicle would be illuminated only by its exhaust, which may not be visible with the unaided eye. Ted Molczan Data for use in Skymap trj file: From left to right, the four columns contain: - time since launch, seconds - latitude, deg N - longitude, deg E - altitude , km 150 29.10 280.08 62 160 29.15 280.15 68 170 29.20 280.23 74 180 29.26 280.31 80 190 30.15 280.21 96 200 30.24 280.28 111 210 30.33 280.37 127 220 30.42 280.45 143 230 30.52 280.54 159 240 30.63 280.64 174 250 30.74 280.75 190 260 30.86 280.86 199 270 30.99 280.98 208 280 31.12 281.11 217 290 31.27 281.25 226 300 31.42 281.39 235 310 31.59 281.55 244 320 31.76 281.71 253 330 31.95 281.89 262 340 32.15 282.08 271 350 32.36 282.29 280 360 32.58 282.51 289 370 32.82 282.74 298 380 33.07 282.99 307 390 33.34 283.26 316 400 33.62 283.55 325 410 33.93 283.86 334 420 34.25 284.19 343 430 34.59 284.54 352 440 34.95 284.93 361 450 35.34 285.34 370 460 35.75 285.78 379 470 36.18 286.25 388 480 36.64 286.76 397 490 37.13 287.32 406 500 37.64 287.91 415 510 38.19 288.56 424 520 38.77 289.25 433 530 39.38 290.01 442 540 40.02 290.82 451 550 40.70 291.71 460 560 41.42 292.68 469 570 42.18 293.73 478 ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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