[CESG] [EXTERNAL] SCID V2 X-Band depletion

[Lux, Jim (US 3370)]

Comment on snip below


  1.  Even more importantly, these parameters are typically not fixed and singular for any given spacecraft.  Many spacecraft design in and use more than one modulation and coding, some have large tables of different combinations for different apertures.   As a consequence, this approach will just not work as a discriminator.


A quick look at a bunch of recent and not so recent missions from JPL shows that at least on the downlink multiple rates, subcarrier frequencies (or direct), and codes is pretty common, if not universal.  Operationally, they’re typically selected by some sort of uplink command.

Voyager (to pick an old example) can either transmit uncoded (at 40bps) or convolutionally coded at rates between 10 bps and 115.2 kbps.

The MER rovers (Spirit and Opportunity) have two different convolutional codes (7,1/2) and (15, 1/6), as well as Turbo at various rates, and uncoded.

Several missions have a different “library” of modulations, codes, and rates depending on the phase of the flight (cruise vs EDL vs surface ops, for instance)

Not only that, but it’s not unheard of to change coding and data rates after launch to allow capabilities that were not part the original design. I believe that this has been done several times on the Electra UHF transceivers.

Jim Lux
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.ccsds.org/pipermail/cesg/attachments/20241024/381c1ecb/attachment.htm>