[amsat-bb] HEO opertunity

[Paul Stoetzer]

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.

73,

Paul, N8HM

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
> budget.
>
> 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
> operations.
>
> 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
>> to
>> mitigate the radiation and who wants to help the students?
>>
>>
>> http://www.ulalaunch.com/ula-announces-2016-cubesat-stem-win
>> ners.aspx?title=
>> United+Launch+Alliance+Announces+CubeSat+STEM+Education+Program+Winners
>> <http://www.ulalaunch.com/ula-announces-2016-cubesat-stem-wi
>> nners.aspx?title
>> =United+Launch+Alliance+Announces+CubeSat+STEM+Education+
>> Program+Winners&Cat
>> egory=News> &Category=News
>>
>>
>>
>>   73's and see you on the baot
>>
>> nick k5qxj
>>
>>
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>
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