Thuraya : Why launch from 0 deg. N into 6 deg inclination?

Both Thuraya 1 and 2 were launched on Zenit SL from equatorial located Odyssey
mobile platform. Although the platform was located (as far as I can tell) at 154W 0N
the launch /target/ at satellite separation was 6.3deg. Wouldn't that introduce a fuel
life penalty?

http://www.sea-launch.com/past_thuraya.html
http://www.sea-launch.com/past_thuraya2.html

In article ,
Paul Blay wrote:
Both Thuraya 1 and 2 were launched on Zenit SL from equatorial located Odyssey
mobile platform. Although the platform was located (as far as I can
tell) at 154W 0N the launch /target/ at satellite separation was
6.3deg. Wouldn't that introduce a fuel life penalty?

Only a small one. Doing a small plane change as part of a large burn
(e.g., GSO insertion) is almost free.

Which doesn't explain *why* they did this. Sea Launch can pretty much
dial in your choice of orbit inclination. For the first few launches,
they did launch at a slight inclination to avoid any possibility that a
launch failure could drop debris on the Galapagos, but that's long since
been discontinued -- they *have* done launches to essentially zero
inclination.

It might perhaps be a constraint on where the second stage falls. It's
not uncommon for Zenit 3SL second-stage burnout to be in a suborbital
trajectory, with the third stage supplying the final push to an initial
parking orbit. Not *all* the suborbital-staging launches have been at a
significant inclination, mind you, but it could be a function of things
like payload mass.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

"Henry Spencer" wrote ...
In article ,
Paul Blay wrote:
Both Thuraya 1 and 2 were launched on Zenit SL from equatorial located Odyssey
mobile platform. Although the platform was located (as far as I can
tell) at 154W 0N the launch /target/ at satellite separation was
6.3deg. Wouldn't that introduce a fuel life penalty?

Only a small one. Doing a small plane change as part of a large burn
(e.g., GSO insertion) is almost free.

Which doesn't explain *why* they did this. Sea Launch can pretty much
dial in your choice of orbit inclination. For the first few launches,
they did launch at a slight inclination to avoid any possibility that a
launch failure could drop debris on the Galapagos, but that's long since
been discontinued -- they *have* done launches to essentially zero
inclination.

It might perhaps be a constraint on where the second stage falls. It's
not uncommon for Zenit 3SL second-stage burnout to be in a suborbital
trajectory, with the third stage supplying the final push to an initial
parking orbit. Not *all* the suborbital-staging launches have been at a
significant inclination, mind you, but it could be a function of things
like payload mass.

Actually the answer turned out to be that Thuraya doesn't do N/S
stationkeeping. The initial inclination was chosen so that natural
changes would gradually bring it down 'n' through zero inclination
so that it would be at a reasonable inclination for as much of its
design life as possible.