Re: Shuttle-ISS Question

From: Bjoern Gimle (b_gimle@algonet.se)
Date: Sun Apr 22 2001 - 00:27:06 PDT

  • Next message: Leo Barhorst: "Obs April 21/22"

    > smaller orbit than the ISS, and then attains a speed faster than rated
    > for that orbital plane, which makes it gain altitude and go faster than
    > the ISS.  Thus, when the Shuttle comes up to ISS's orbital plane, the two
    ...
    
    One issue in Jonathan's mail was not addressed by Ron. When 'driving in
    the fast lane' STS must increase speed FURTHER to reach the ISS height.
    But in this elliptical transfer orbit, speed decreases with height, so
    it reaches ISS with a LOWER speed, and must accelerate once MORE to stay
    at the target height.
    
    Actually, this was NOT done in 1/2 orbit.
    
    In the low orbit (e.g. elset #7, orbit #17) MM was 0.33 higher than ISS',
    so STS was gaining on ISS by about 30 min/day, or 2 min/orbit.
    
    In elset #8, orbit 22 and #9, orbit 24, the MM is only 0.1 higher than
    ISS', gaining 9 min/day or 0.6 min/orbit.
    
    With these small MM differences, and the 4 min launch window, the times
    of orbit transitions (and the heights of the low orbits) must be choosen
    carefully to make a close encounter near the 374 km ISS perigee.
    
    The low orbit makes it possible to dock within two days, and in combination
    with the intermediate orbit allows fine-tuning of the docking.
    
    STS-100                                          392 x 374
    1 26747U 01016A   01111.47436995  .00002971  00000-0  33689-4 0   101
    2 26747  51.5717  14.4828 0013430 300.3685  59.5979 15.61579599   288
    STS-100                                          376 x 331
    1 26747U 01016A   01111.25118354  .00005260  11738-9  38153-4 0    95
    2 26747  51.5671  15.6150 0033057 168.0950   9.9475 15.71902981   241
    STS-100                                          376 x 331
    1 26747U 01016A   01111.09262737  .00005256  11717-9  38109-4 0    84
    2 26747  51.5696  16.4324 0033132 167.6160 192.5659 15.71905971   225
    STS-100                                          332 x 248
    1 26747U 01016A   01110.77610761  .00023889  23864-8  50073-4 0    72
    2 26747  51.5683  18.0687 0063248   6.1685 354.0086 15.94451667   177
    
    
    -----------------------------------------------------------------
    Unsubscribe from SeeSat-L by sending a message with 'unsubscribe'
    in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org
    http://www2.satellite.eu.org/seesat/seesatindex.html
    



    This archive was generated by hypermail 2b29 : Sun Apr 22 2001 - 00:33:36 PDT