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Satellite Struggle: Newsletter Challenge (June 2017)

Posted May 31, 2017 5:01 PM
Pathfinder Tags: challenge question satellite

This month's Challenge Question: Specs & Techs from GlobalSpec:

Column 54 through 61 of a TLE set for the IRIDIUM 20 satellite has a value of -21027-4. What is this number’s meaning, and what are the physical implications of its negative value?

The answer to this challenge will be posted later this month, right here on CR4.

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#1

Re: Satellite Struggle: Newsletter Challenge (June 2017)

05/31/2017 5:25 PM

Extra credit for not looking up the BSTAR formula?

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#2

Re: Satellite Struggle: Newsletter Challenge (June 2017)

05/31/2017 6:53 PM

It has a negative attitude towards its NEXT replacement ?...

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Re: Satellite Struggle: Newsletter Challenge (June 2017)

05/31/2017 8:21 PM

-21027-4 means BStar, or B*, = -0.21027 x 10-4 earth-radii -1

BStar is (1/2) times the ballistic coefficient of the satellite, B, times a standard atmospheric density, ρ0.

BStar = Bρ0 /2.

ρ0 = 0.1570 kg/m^2/Earth radii.

Lower BStar means the satellite will be less affected by atmospheric drag (longer lifetime).

http://www.castor2.ca/03_Mechanics/03_TLE/B_Star.html

https://en.wikipedia.org/wiki/BSTAR

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