Team:
The Eagle Chief Technology Officer (W2GPS), the AMSAT VP Engineering
(N4HY) and I met (electronically) to discuss the Eagle payload complement.
We have decided the following should be our recommendation to the board of
directors of AMSAT for their ratification. This is what will be presented to the BoD:
1. Services to be provided, as defined at the San Diego meeting et seq:
Class 0 is linear transponder users
Class 1 is SMS text message service users
Class 2 is weak signal voice grade digital channel
Class 3 is strong signal, large antenna, higher bandwidth signal (think
compressed full motion video)
2. Primary class 0 payload: U/V with a design goal that it be usable over
75% of the orbit.
3. Primary class 1 payload: U/V for the reasons discussed at San Diego.
3. Primary Class 2 and 3 ACP payload: S2/C usable over 75% of the orbit. This
coverage to be accomplished by using electronically de-spun phased arrays on S2 and C.
At San Diego, we discussed S2 vs. S1. S2 was technically superior, but other issues
caused us to shy away from it. Upon reflection, the leadership has decided to proceed
down the technically superior path, S2 uplink.
4. Secondary Class 0 payload: L/S1 -if and when the power budget and
antenna pointing (fixed, nadir-pointing array) can support. We recognize that it may not be usable
in many areas due to elevated noise floor resulting from 802.xx devices, as discussed in San
Diego and documented in measurements and analysis.
NO PERFORMANCE LEVEL IS TO BE PROMISED.
5. Secondary ACP Class 2 uplink: A separate L receiver feeding same DSP and C-band
downlink when fixed nadir-pointing antenna array supports. This second receiver will share
the L-band LNA and antenna with the L/S1 Class 0 payload.
The greater level of service for S2 users should encourage people who can to use S2 rather than L.
NO PERFORMANCE LEVEL IS TO BE PROMISED.
6. Use of all secondary payloads will be subject to acceptable costs in power, heat, and/or mass,
as assessed by analysis or testing. They are to be turned off if regulatory constraints are
imposed post launch. They will not be flown at all if shown to be not feasible through
analysis or testing.
This is what I will present to the board at Symposium for their concurrence. Please contain this
discussion within the Eagle team until the Board makes a decision.
I request your comments within the next 48 hours so that I can finish the budget tonight and begin
crafting my presentation to the board and my follow-on presentation at Symposium. We need to bring
this to closure so that we can present decisions at Symposium, and move out smartly from there. Thanks.
Very 73,
Jim
wb4gcs@amsat.org
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