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SEDSAT Orbital Data - Revised Estimated



I appear to have made an incorrect assumption in the initial estimation
of the SEDSAT orbit.  I had believed that the orbital data applied to
a 22 October launch date.  After checking the KSC web site, I discovered
that the launch is actually scheduled for 24 October.  Since the orbital
data supplied was time-dependent, it's not simply a matter of of updating 
Keps from the state vector.  I have therefore revised the vector and 
Keplerian data to match what I believe was the intended reference date.  
Revised orbital information is listed below.

--------------------------------------------------------------------------

The following orbital data was estimated based on orbital information
received from Dr. Mark W. Maier of the University of Alabama in Huntsville.  
>From this I derived the Earth-fixed, time-independent state vector listed
below.  Note that 90001 is a temporary catalog number and that a permanent
catalog number and international designator will be assigned once SEDSAT-1
is launched.

Vector format = 10107
Satellite Name:         SEDSAT-1
Catalog Number:         90001            
Epoch MET:                  0.06134259300
                           0/01:28:20.000 MET
EFG E:                       -5053.605008 km
    F:                       -4242.519843 km
    G:                        3536.547077 km
    Edot:                     4.769243031 km/s
    Fdot:                    -4.403951431 km/s
    Gdot:                     1.615837362 km/s
ndot/2 (drag):              0.00000214743 rev/day^2
nddt/6:                       0.00000E+00 rev/day^3
Bstar:                        4.38589E-05 1/Earth Radii
Elset #:                                1
Rev @ Epoch:                2.17799158319

The Keplerian elements are based on the nominal launch time of 1998-OCT-24
at 12:00:10 UTC.  The Two-Line and AMSAT formats are listed below.

SEDSAT-1    
1 90001U          98297.56145833  .00000215  00000-0  43859-4 0    15
2 90001  31.5103  33.8627 0402839 252.7761 171.3099 14.19599697    22

Satellite: SEDSAT-1    
Catalog number: 90001
Epoch time:      98297.56145833
Element set:       1
Inclination:       31.5103 deg
RA of node:        33.8627 deg
Eccentricity:    0.0402839
Arg of perigee:   252.7761 deg
Mean anomaly:     171.3099 deg
Mean motion:   14.19599697 rev/day
Decay rate:    2.14743e-06 rev/day^2
Epoch rev:               2
Checksum:              303

If the launch date or time changes, the updated Keplerian elements can be
computed by inputting the above state vector into VEC2TLE and providing the
new launch date and time.  Questions or comments should be directed to Ken
Ernandes, N2WWD at the email address listed below.

Ken Ernandes
n2wwd@amsat.org
http://www.mindspring.com/~n2wwd
Ken Ernandes
n2wwd@amsat.org
http://www.mindspring.com/~n2wwd


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