Wikipedia says that Telstar 1 was put into a 952 x 5933, 2.6 hour 44.8° MEO orbit but doesn't really say exactly why this particular orbit was selected.
Did it perhaps behave roughly like a Molniya orbit?
$\begingroup$
$\endgroup$
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
9
The orbit was chosen as a tradeoff between communication capabilities and the available performance of the launch vehicle.
Study of available boosters led to the Delta configuration of the Thor as the simplest and most reliable rocket for these purposes. Its relatively limited lifting capacity set a bound of about 180 pounds for a useful orbit. This was established as: apogee 3450 miles, perigee 575 miles, inclination to equator 45 °. The apogee is high enough to give good mutual visibility between northeastern United States and western Europe. Calculations for a working worldwide system indicate the desirability of circular orbits at 6000-8000 mile elevations; however, these were not achievable with the Delta vehicle.
Source: The Telstar Experiment, included in NASA SP-32 Volume I
answered Dec 10, 2021 at 17:12
-
1$\begingroup$ I see, not just the apogee's altitude, but its location above 45° north latitude between the two "customers". And since it was essentially a short-lived demonstration/test, no need to worry about managing precession like the Molnya orbit. $\endgroup$– uhohCommented Dec 10, 2021 at 21:23
-
1$\begingroup$ @uhoh you'd probably enjoy a read through SP-32. $\endgroup$ Commented Dec 10, 2021 at 21:24
-
1$\begingroup$ Perfect! It's 5:30 AM, I got up to check for clear skies to see comet Leonard but no luck so I've got some nice, quiet reading time ahead of me this morning. $\endgroup$– uhohCommented Dec 10, 2021 at 21:28
-
2
-
1$\begingroup$ There is a longer discussion of the orbital choice in the 2nd chapter, but it boils down to what I posted. BTW, there is a volume 3 as well. ntrs.nasa.gov/api/citations/19640001170/downloads/… $\endgroup$ Commented Dec 10, 2021 at 21:42