Re: [amsat-bb] was Arcjet, now solid boosters

[tlang@xxxxxxxxxxxxxxxxxxxx (Tony Langdon)]

Hello Edward!

05 Jun 01 00:02, you wrote to All:

 EC> Yes, I understand.  If AO-40 had not run into trouble, it would have
 EC> been placed into a 63 degree inclination orbit resulting with exactly
 EC> that circumstance for stations in the southern hemisphere.   The
 EC> current orbit with ~6 degree inclination provides a more equitable
 EC> situation for you.  I guess this may be one of the better outcomes
 EC> from your perspective!

Ironically, the propulsion problems have had a significant silver lining for
us! :)

 EC> We in the far north would have had multiple passes every day, which
 EC> would have been great.  Well, the GTO gives us no view at perigee {its
 EC> below our horizon}, but we do have an apogee view.  The recent low

No different here.  We're at 37S, so way outside the perigee footprint.

 EC> note that the good passes would run for about three days followed by a
 EC> couple days with unsuitable viewing or completely missing a pass
 EC> [perigee passes].  I suspect a similar pattern with you down there.  I

Yes, much the same here..

 EC> have not done an exhaustive study, but with just casual observation
 EC> it
 EC> seems the current orbit is limited to about a max elevation of ~30
 EC> degrees for me.  Since the surrounding 15m high forrest can obscure
 EC> AOS and LOS up to about 10
 EC> degrees, this does limit us some {I have chainsaw plans for some of
 EC> those trees} :>)  This is one reason the sat-antennas are up on the
 EC> roof.

As I said, can get to around 48 degrees when apogee falls near due North.

 EC> Amsat-DL indicates that the initial arc-jet boost will only raise
 EC> perigee by about 200 km.  Perigee will only be ~500 km which will
 EC> severely limit range for everyone able to view it.  The S2 footprint
 EC> will be further limited, where the V or U low-gain antennas would have
 EC> performed better for perigee.  I wonder if there any intension or hope
 EC> of raising perigee to 4000 km?  I might just have a small view at that

4000 km would at least allow trans equatorial contacts from here into perhaps
as far north as China.  Bit different to the original planned 4000km perihee,
which at 63S would have only yielded contacts with suitably licenced penguins!
LOL

 EC> altitude, and the footprint would extend further.  I think that would
 EC> beneefit everyone.  The current precession seems to place apogee
 EC> always late at local nightime.  I wonder if it will slowly change
 EC> {probably on an annual basis}.  This precludes much operation for me
 EC> during the week when I must get sleep in order to go to work.  But I
 EC> guess this is true for many.

Much the same here as well, just have to wait for precession to bring the orbit
around to the right position.  From our perspective, a low inclination orbit
with a perigee in the 5000-10000km range and apogee near 40000km is probably
the ideal orbit.  Gives a range of operating conditions and the chance to work
come DX on the other side of the world as well as regional contacts with more
modest equipment.

 EC> Well, AO-40 and phase-jj are GTO birds, so I guess that will be a
 EC> welcome situation for you, and it will work out for us, too.  I
 EC> certainly am happy to have a new satellite up with a promise of
 EC> "normal" operation soon {hoping that the momentum wheels work and
 EC> solar panels will extend OK}.  We should be able to work each other
 EC> occasionally.  I have almost everything ready now; only waiting on the
 EC> 2.4G preamp and have yet to test the 1.2G convertor.

I'm a little while off, but certainly don't want to miss out on the fun! :)

Tony, VK3JED

.. Blue Wave! Not just for FIDONet anymore!
--
|Fidonet:  Tony Langdon 3:633/284.18
|Internet: tlang@freeway.apana.org.au
|
| Standard disclaimer: The views of this user are strictly his own.


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