[Ground-station] Ground-Station Digest, Vol 34, Issue 21

[Thomas Parry]

This is not my area of expertise at all. But I have heard people that do
know what they're talking about say its very hard to analytically predict
re-entry at low altitudes with real satellite geometries.

With a spherical satellite everything is well behaved but with different
drag coefficients at different angles from square-ish satellites the
behaviour becomes chaotic and the window of possible solutions widens
dramatically.

Not really a useful answer but maybe a interesting thing to think about.

Cheers,
Thomas


On Sat, 30 Jan 2021, 22:03 ,
<ground-station-request at lists.openresearch.institute> wrote:

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>    1. GMAT vs. STK/HPOP - call for help (Michelle Thompson)
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> ----------------------------------------------------------------------
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> Message: 1
> Date: Fri, 29 Jan 2021 17:28:20 -0800
> From: Michelle Thompson <mountain.michelle at gmail.com>
> To: Michelle Thompson via Ground-Station
>         <ground-station at lists.openresearch.institute>
> Subject: [Ground-station] GMAT vs. STK/HPOP - call for help
> Message-ID:
>         <CACvjz2UOeHpUmGgtvqTS=Y4WQ4_XDLyQRu_7=
> qw13bY_hzevFg at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> For the Debris Mitigation presentation to the FCC, we want to give answers
> (and show our work) about how much delta-v we need for some of the proposed
> orbits for minimum viable amateur spacecraft in the Amateur Radio Satellite
> Service.
>
> There's a question that Jan King and I have about a critical altitude and
> low surface_area:mass ratio spacecraft. It occurred to us that we really
> might want to compare results across two or more software packages to build
> some confidence.
>
> Jan has a set of results from a spreadsheet from SMAD.
>
> https://smad.com/
>
> The calculation under review is around 165km with a relatively lightweight
> 6U spacecraft. It's acting like it wants to do some strange things. Is this
> physics, or at a limit of the model?
>
> We have a couple of people who are good or are getting good at GMAT.
>
> https://software.nasa.gov/software/GSC-17177-1
>
> Question: Are the atmospheric models in GMAT good enough for this
> calculation?
>
> Does anyone have access to STK/HPOP to run this calculation, for
> comparison?
>
> https://www.agi.com/products/stk
>
> https://help.agi.com/stk/11.0.1/Content/hpop/hpop.htm
>
> Thank you,
> -Michelle W5NYV
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