Re: Lowest orbit and DeltaV
- From: BradGuth <bradguth@xxxxxxxxx>
- Date: Wed, 11 Jun 2008 15:28:29 -0700 (PDT)
On Jun 11, 8:21 am, "Jeff Findley" <jeff.find...@xxxxxxxxxxxxxx>
wrote:
"Jim Relsh" <jre...@xxxxxxxxxxxxxx> wrote in message
news:47f76$484fa12a$23972@xxxxxxxxxxxxxxxxxxxx
What's the lowest practical orbit for a satellite to be in? I think I read
somewhere that it was about 150km or so, but I keep wondering how they
determine this. And what is the corresponding DeltaV to get into that
orbit?
Not to sound like President Clinton, but that all depends on how you define
the word practical.
The ballistic coefficient of an object in a very low earth orbit has a huge
impact on how long it takes that object's orbit to decay. You could
determine the minimum orbital altitude which would keep a one ton sphere of
depleted uranium in orbit for a day, but is that really practical? Who
would orbit such a thing for such a short period of time?
Jeff
Spy satellites originally didn't much care for staying up all that
long, mostly because they needed to obtain the best image resolution
and also had loads of large-format film to develop, as well as
because onboard film processing and digital scanning wasn't fully
developed until our Apollo missions required such. At times, a few
days was good enough.
- Brad Guth Brad_Guth Brad.Guth BradGuth
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