ABOUT MOLNIYA-3
about_molniya
prec_molniya
rho_theta_molniya_3
The elements of typical Molniya are 40000/500 kms/63.4°.
Such elements
give a semi major axis A=(40000+500)/2+6378=26628kms
C=26628-(6378+500)=19750
kms
Excentricity=C/A=19750/26628=.7417
Period T=26628^1.5/6028.9/60
=12.0120876 hours
Nb rev/day=24/12.012=1.99798 rev/day
Perigee rotation
+4*10^-4°/day
Nodes precession –1.1338°/day
Among the series Molniya-3, we
found a different one N°24640 in Heavens above base with such
data.
Apogee=36544 kms**Perigee=94 kms**Inclination 63.6391°.
The perigee
and apogee are very low compared to that of typical Molniya. (may be a problem
of propulsion during the launch).
These data induce 2.236 revolutions every
day instead of 2 and a precession of –1.17°/day of the ascending node and
–3*10-3 °/day of the perigee instead of ~0°
habitually.
Consequences.
1)The transits can take place over FRANCE during night and because of the shift of the perigee , on a height very inferior to 36000 kms.
2)The rotation of the perigee (-12°=-11*365*3*10^-3 since the
launch on 1996) induce a change of the aspect of the north ground track because
the speed of rotation of the earth can balance that of Molniya at a decreasing
latitude and not only at 63.6 as it was the case generally.
Because the
argument of perigee decrease and so about the apogee, the height of the
satellite increase with years during the zenital ascending transits(ZAT) and
decrease during the zenital descending transits(ZDT) over FRANCE.
If Molniya
X (by ex 15738)has an argument of perigee increasing, the height of zenital
ascending transits(ZAT)decrease and height of zenital descending transits(ZDT)
increase over FRANCE.
We will tackle the aspect of loop of the ground track near apogee on REVOSAT 2008.