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Old December 6th 18, 01:27 AM posted to sci.space.policy
Alain Fournier[_3_]
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Default SpaceX launch today was third use of a first stage

On Dec/5/2018 at 15:46, Fred J. McCall wrote :
"Rocket Man" wrote on Wed, 5 Dec 2018
12:18:10 +0100:

Is there some reason why you top post or are you just clueless?

Many people think these satellites wil de-orbit in a couple of months, but
that's far from the truth. Most of them have been dropped in an orbit about
400km up and will take many decades to de-orbit.


Nonsense! While orbital decay times depend on the precise orbital
elements, objects in 400 km orbits decay in about a year. To stay up
"many decades" they'd have to be 600 km or more high.


Orbital decay also depends on the mass to effective area ratio. In this
case, since we are talking about small satellites, the mass to effective
area ratio should be small and therefore the satellites should decay
faster than more massive satellites.


Alain Fournier