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

[anshul makkar]

Hi Michelle,

Please can you share the Jan's spreadsheet or any script that he might
have written. I can use it to compare the GMAT script that I have and
include any additional factors into my deltaV calculations for GEO to
Graveyard orbit.

Thanks
Anshul Makkar

On Sun, Jan 31, 2021 at 7:54 AM anshul makkar <anshulmakkar at gmail.com> wrote:
>
> Hi,
>
> Not expert in this area and still learning, I found a help page :
> http://gmat.sourceforge.net/docs/R2018a/help.html which talks about
> configuring atmospheric models.
>
> Also, a brief web research showed that people have used the GMAT
> atmospheric model to configure their mission.
>
> For my script "GEO to graveyard orbit", I am only using the Gravity
> Field Force Model.
>
> I can (based on your post I believe I need to ) introduce Atmospheric
> model related coefficients and provide the deltaV comparative results.
>
> Thanks
> Anshul Makkar
>
> On Sat, Jan 30, 2021 at 9:51 PM Thomas Parry via Ground-Station
> <ground-station at lists.openresearch.institute> wrote:
> >
> > 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:
> >>
> >> Send Ground-Station mailing list submissions to
> >>         ground-station at lists.openresearch.institute
> >>
> >> To subscribe or unsubscribe via the World Wide Web, visit
> >>         http://lists.openresearch.institute/listinfo.cgi/ground-station-openresearch.institute
> >>
> >> or, via email, send a message with subject or body 'help' to
> >>         ground-station-request at lists.openresearch.institute
> >>
> >> You can reach the person managing the list at
> >>         ground-station-owner at lists.openresearch.institute
> >>
> >> When replying, please edit your Subject line so it is more specific
> >> than "Re: Contents of Ground-Station digest..."
> >>
> >>
> >> Today's Topics:
> >>
> >>    1. GMAT vs. STK/HPOP - call for help (Michelle Thompson)
> >>
> >>
> >> ----------------------------------------------------------------------
> >>
> >> 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
> >> -------------- next part --------------
> >> An HTML attachment was scrubbed...
> >> URL: <http://lists.openresearch.institute/pipermail/ground-station-openresearch.institute/attachments/20210129/1a54774f/attachment-0001.html>
> >>
> >> ------------------------------
> >>
> >> Subject: Digest Footer
> >>
> >> _______________________________________________
> >> Ground-Station mailing list
> >> Ground-Station at lists.openresearch.institute
> >> http://lists.openresearch.institute/listinfo.cgi/ground-station-openresearch.institute
> >>
> >>
> >> ------------------------------
> >>
> >> End of Ground-Station Digest, Vol 34, Issue 21
> >> **********************************************
> >>