Mars-96 track

Bjoern Gimle (b_gimle@algonet.se)
Sat, 16 Nov 1996 00:39:44 +0100 (MET)

Vladimir Agapov has in three mails given information on the launch
sequence of Mars-96 today (Nov.16) or tomorrow.

Neil Clifford has produced two-line-elsets for the LEO parts of the
track, but I failed to make VEC2TLE produce orbits for the last two
points given by Vladimir Agapov (speed already above escape velocity??)=20
....
>>I wrote in previous message wrong time of launch of Mars-96. It would be
>>proper times in case of launch from LC81L. Since launch will take place
>>from LC200L (46deg02'22" N, 63deg01'58" E) proper times are

2048:52.9 UT on Nov 16
2048:24.3 UT on Nov 17 (alternate opportunity).
------------------------
5. Block D-2 maine engine cut-off #2 (T0+4663.980 sec).
22:06:36.732 UTC J2000   (ECI?) X,Y,Z, Xdot, Ydot,Zdot:
 6212.627  2669.722   862.110 -1.802765  6.376021  8.402991
-------------------------------------------
Spacecraft will be separated from the Block at T0 + 4677.2 s.
It will be inserted into following orbit (osculating orbit parameters at the
moment of separation are given): e=3D0.96048, a=3D166820.23 km, w=3D348.22=
 deg,
i=3D51.79, true anomaly=3D22.22 deg, period T=3D7.85 days.
.....
T0+4677.20    - separation of the spacecraft from the Block D-2,
                8.24 N, 4.07 W, 464.16 km
......
6. Spacecraft separation from the Block D-2 (T0+4678.04 sec). Orbit for
the Block D-2 upper stage.

22:06:50.792 UTC J2000   (ECI?) X,Y,Z, Xdot, Ydot,Zdot :
 6186.508  2759.043   980.156 -1.912012  6.328447  8.387033

------------------------
T0+4916.953   - end of the main engine burn, 23.44 N, 8.24 E, 1174.09 km
......
I'll try to prepare files with nominal state vectors in J2000 and B1950 for
this launch profile (points with some step, for example 10 min)

----------------------------------------
The epoch given as T0+4677.20 would correspond to an elset Epoch of
96321.92141319. The true anomaly (22.22 degrees) agrees with perigee
longitude and current latitude, and the time since perigee is about
4.0 minutes, or  0.00035 orbits, which would make Mean Anomaly=3D0.13.

Since the inclination is close to the last LEO orbit by Neil Clifford,
I would expect RAAN to be just as close, or about 17.53 degrees.

So, my first guess of the orbit was :

(320669x215 km)
1 96000U          96321.92141319  .00000003  10000-7  10000-7 0    13
2 96000  51.7900  17.5306 96048   348.22     0.1270   0.1273885350315

This, however, makes TRAKSTAR predict a position=20
1996 Nov 16  22:06:00   28=F844'34" S   165=F824'27" W  31168.867   =20
1996 Nov 16  22:07:00   28=F852'23" S   165=F830'53" W  30937.114   =20
, still moving South, towards the perigee !!

SkyMap 5.11 appears to predict the pass time approximately correct,
but at a much too large distance ?

I must set MA to 4.0000 to get the TrakStar prediction close to
the stated position!
1996 Nov 16  22:05:00    4=F824'43" N     6=F841'50" W    765.787 ECL
1996 Nov 16  22:06:00    8=F818'03" N     3=F855'28" W    867.542 ECL
1996 Nov 16  22:07:00   12=F802'44" N     1=F811'19" W    993.633 ECL

This would get the Block D-2 engines appear sunlit at about :
1996 Nov 16  22:23:00   46=F842'20" N    39=F849'13" E   4991.618 ECL
1996 Nov 16  22:24:00   47=F833'27" N    42=F804'41" E   5294.932   =20

, and the Mars-96 spacecraft approximately the same time.