[Orekit Users] picosatellite biomagnetorquer experiment - request for answers/ideas/comments

[Michael Turner <michael.eugene.turner@gmail.com>]

Dear Orekit list members,

I have a question about Orekit capabilities. Zac Manchester is copied
on this e-mail because he's making the relevant spacecraft; Kartik
Madiraju is copied because I've engaged him on related (but somewhat
tangential) issues related to magnetorquing. Please remove them from
the CC list if they ask to be dropped.

I've been contributing to the Orekit wiki, but so far only at the
level of copyediting -- fixing typos, small grammatical errors, etc.
I'd hoped to learn more orbital dynamics by osmosis, so that I could
answer any questions I might have on my own. Unfortunately, I have
several other projects competing for my time. At this point, I can
only say that helping with the Orekit wiki has improved my orbital
dynamics *vocabulary* a little, while also helping me appreciate what
a complex subject it is.

Orekit might be very useful for one of my current projects. However,
I'd like to be sure, before committing to Orekit.

The project involves KickSat sprites - picosatellites launched from a
Cubesat. For a quick overview, see the Wikipedia article about
KickSat:

   http://en.wikipedia.org/wiki/KickSat

and the video in the original Kickstarter solicitation

   http://www.kickstarter.com/projects/zacinaction/kicksat-your-personal-spacecraft-in-space

I have donated enough to KickSat qualify for the launch of a
customized sprite. I want to make this spacecraft part of a science
education project here in Japan, and in some other countries if
possible.

My specific project involves attaching a lightly magnetized strip to
the sprite before launch, then measuring and transmitting the amount
of magnetorquing the sprite undergoes before it deorbits. For two
reasons, I'd like to be very sure of the theoretical *minimum* magnet
strength that could cause any measurable change in orientation.

(1) a magnet that's too strong might be disqualified as potentially
interfering with other sprites in KickSat;

(2) I hope to use biologically derived biomaterials (bacteria or algae
containing magnetosomes) to make the strip a magnet; the maximum
achievable strength might be quite low.

Because these sprites have a very high ballistic coefficient, and will
be ejected from the Cubesat at around 300 km (?), they will deorbit
fairly soon (weeks?). So it's important to be able to filter out any
attitude changes that are due only to increasing atmospheric drag.

Orekit appears to have models for atmospheric drag (though not much
wiki documentation yet on this?), and even the beginnings of a
tutorial about geomagnetic field modeling. In exchange for help with
questions, I would be more than happy to help flesh out any Orekit
documentation that already exists on these two topics, as needed. I
would also be happy to contribute to the Orekit documentation any
tutorial examples that come out of my own project.

Regards,
Michael Turner
Project Persephone
Tokyo