karn@mouton.UUCP (09/29/84)
Here is a predicted element set for orbit 23 of the upcoming Challenger mission. Note, however, that it was based on an October 1 launch and needs to have its RA (right ascension) of the ascending node adjusted for the actual launch time, which I believe is currently scheduled for October 4. Epoch time: 84276.85138889 Tue Oct 2 20:26:00.0 1984 UTC Inclination: 57.2007 deg RA of node: 68.7538 deg Eccentricity: 0.0010544 Arg of perigee: 346.2766 deg Mean anomaly: 14.1415 deg Mean motion: 15.97849766 rev/day Decay rate: 0.046 rev/day^2 [incredibly high! -- prk] Epoch rev: 23 Semi major axis: 6658.131 km Anom period: 90.121113 min Apogee: 287.857 km Perigee: 273.816 km Ref perigee: 2466.84893045 Tue Oct 2 20:22:27.590 1984 UTC The high inclination of this mission will make the orbiter visible at much higher latitudes than most shuttle missions. It will also make it possible for more amateurs to receive the 435 mhz transmissions of a Getaway Special experiment that will be mounted in the cargo bay. Tracking the shuttle, however, has always proven to be extremely difficult due to the unpredictable drag effects of the low orbit and the constant perturbations of maneuvering rockets. As we found with STS-9, predictions made from element sets which were only a day old could be off by minutes. Phil Karn
s170@sol1.UUCP (s170) (10/01/84)
> Here is a predicted element set for orbit 23 of the upcoming Challenger > mission. Note, however, that it was based on an October 1 launch and needs > to have its RA (right ascension) of the ascending node adjusted for the > actual launch time, which I believe is currently scheduled for October 4. > > Epoch time: 84276.85138889 > Tue Oct 2 20:26:00.0 1984 UTC > Inclination: 57.2007 deg > RA of node: 68.7538 deg > Eccentricity: 0.0010544 > Arg of perigee: 346.2766 deg > Mean anomaly: 14.1415 deg > Mean motion: 15.97849766 rev/day > Decay rate: 0.046 rev/day^2 [incredibly high! -- prk] > Epoch rev: 23 > Semi major axis: 6658.131 km > Anom period: 90.121113 min > Apogee: 287.857 km > Perigee: 273.816 km > Ref perigee: 2466.84893045 > Tue Oct 2 20:22:27.590 1984 UTC > > The high inclination of this mission will make the orbiter visible at much > higher latitudes than most shuttle missions. It will also make it possible > for more amateurs to receive the 435 mhz transmissions of a Getaway Special > experiment that will be mounted in the cargo bay. Tracking the shuttle, > however, has always proven to be extremely difficult due to the unpredictable > drag effects of the low orbit and the constant perturbations of maneuvering > rockets. As we found with STS-9, predictions made from element sets which > were only a day old could be off by minutes. > > Phil Karn *** REPLACE THIS LINE WITH YOUR MESSAGE *** <obligatory line-eater sacrifice> In reference to the orbital element state-vector, does someone have an easily transportable algorithm (or program, even) that will give longitude/ latitude predictions, visibility/altazimuth, etc? I know I'm asking a lot, but it sure would be neat. I know the ham elements out there must have some such thing, but I haven't subscribed to QST in some time, now. Anybody seen anything like it? I have a PC-compatible, Turbo Pascal, and even (choke, gag!) MS Basic. Thanx for listening (reading?). Russ Schnapp (...akgua!sol1!s170)