[amsat-bb] HEO opertunity
n8hm at arrl.net
Mon Oct 24 15:38:57 UTC 2016
Some sort of linear transponder would be an ideal payload, even if you'd
need a really darn good station to use it (usage of low bit rate digital
modes through the transponder could help). The last ULA launch to GTO that
I could find orbit details for was to 35,789 km x 3,830 km with a 19 degree
inclination. A transponder may only be usable by the best equipped stations
at apogee, but many more stations could use it at perigee.
On Mon, Oct 24, 2016 at 11:20 AM, Zach Leffke <zleffke at vt.edu> wrote:
> Given my recent interest and the previous thread on 'deep space
> tracking,' a linear transponder on a HEO bird could offer an interesting
> 'test bird' to conducting ranging operations and orbit determination with.
> It is more 'deep space like' than the current LEO birds, but is still in
> earth orbit and can be modeled with TLEs (so that we can check against
> NORAD updates to see how 'good' we are doing).
> If the design is similar to what will be used on the CQC bird (or at least
> an approximation that could work in a 1U), then we (as in the amateur
> satellite community) could test out the required earth station hardware /
> backend processing for something like this, as well as get vital training
> for future missions such as the CQC bird and potential other HEO missions.
> Couple of points to back up the idea:
> 1. I'm guessing a 1U in HEO is probably tough power budget wise, so link
> budgets will probably be tight. PN sequence ranging (in my limited
> understanding of the subject) requires way less SNR than normal
> communications and data transfer since your just looking for correlations
> against the known PN sequence, so it is maybe viable given a tighter link
> 2. A 5GHz up/10 GHz down payload is probably not viable in a 1u (link
> budgets, size constraints, etc). So, something like a 23cm up, 70cm down
> bent pipe transponder would be interesting. The problem here will likely
> be community 'backlash' in that L-band uplink stations are less common in
> the Amateur Community. I would offer the argument of 'use it or lose it'
> to help protect the 23cm uplink band, and also the fact that AMSAT is
> planning an L-Band uplink for two of the 5 foxes (including 1E which will
> be a linear transponder). So maybe having another 23cm uplink bird will
> interest people in adding a band to their station (if two birds isn't
> enough, maybe three is?). If L-Band up is too hard to swallow, then a 2m
> up/70cm down bent pipe in HEO would still be interesting, compatible with
> most Amateur ground stations, and could still be used to test ranging
> 3. Heavy Forward Error Correction on a separate low rate TLM downlink
> would probably be a good idea (like AO-73, again due to probably tight
> power budget).
> 4. training, Training, TRAINING! I know AMSAT has conducted ranging on
> their own in the past, but its been a while. There are probably new
> members in the community that would like to get into this sort of thing and
> learn this type of skill (I include myself in that list), and the folks
> that have done it before could help train up a younger/newer generation of
> AMSAT folks, which would help protect the 'technical leadership in the
> field of small sats' future of AMSAT.
> I have no good answer for the radiation part of your question. Also, I'd
> love to help out the students, but have my hands full here with our own
> students at VT.
> Just throwing out an idea for a payload.......
> Congrats on getting a ride!
> -Zach, KJ4QLP
> Research Associate
> Ted & Karyn Hume Center for National Security & Technology
> Virginia Polytechnic Institute & State University
> Work Phone: 540-231-4174
> Cell Phone: 540-808-6305
> On 10/24/2016 2:38 AM, Nick Pugh wrote:
>> Hello AMSAT-ers
>> The University of Louisiana has a slot on a ULA mission to GTO launch to
>> GTO for a 1u. WE are asking the community what payload should we fly, how
>> mitigate the radiation and who wants to help the students?
>> egory=News> &Category=News
>> 73's and see you on the baot
>> nick k5qxj
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