[amsat-bb] BY70-1

[Paul Stoetzer]

I put the parameters from yesterday's TLEs into NASA's DAS software. The
mass is listed at 2 kg, so the unknown variable is the cross sectional
surface area. It's a 2U cubesat with deployed solar panels. With one
estimate, I got 6 days, which is obviously wrong. With another estimate, I
got 96 days.

73,

Paul, N8HM

On Fri, Dec 30, 2016 at 14:45 Nico Janssen <hamsat at xs4all.nl> wrote:

>
>
> As long as we don't have stable TLEs it is not possible to perform
>
> an analysis to determine the expected lifetime. But my initial
>
> guestimate would be somewhere between 2 and 6 months.
>
>
>
> 73, Nico
>
>
>
> On 30-12-16 19:43, Greg D wrote:
>
> > 18:20 pass not as strong as prior passes.  Only got a few moments of
>
> > full-quieting audio.  Contacts with W5ACM and KC7M.  As before, the
>
> > second half of the pass was much better (nothing heard at all until just
>
> > before indicated TCA), so perhaps the bird is late compared to the
>
> > Keps.  Worked it almost into the ground before LOS.  I'm using
>
> > 2016-083C, updated from Celestrak right before the pass.  Playing with
>
> > polarization seemed to help, but I'm assuming the bird's antennas are
>
> > linear, right?  Possibly my relays are getting dirty.
>
> >
>
> > One question, for scale...  We know that the satellite will not last
>
> > "long", given it's crippled orbit.  How long?  Days?  Weeks?  Months?
>
> >
>
> > Greg  KO6TH
>
> >
>
> >
>
> > Nico Janssen wrote:
>
> >> If you are still using yesterday's TLE set, then you will indeed find
>
> >> that BY70-1 is now about half a minute earlier. The problem is that
>
> >> the TLEs for this satellite are not stable yet in the first days after
>
> >> the
>
> >> launch. The right value for e.g. the decay rate has not yet been
>
> >> established. So for the time being you need to make sure you use the
>
> >> most recent TLE set that is available.
>
> >>
>
> >> By the way, the two SuperView satellites are now using their own
>
> >> propulsion system to increase their altitude, preventing an early decay.
>
> >> As BY70-1 does not have any propulsion, it is stuck in its low orbit.
>
> >>
>
> >> 73,
>
> >> Nico PA0DLO
>
> >>
>
> >>
>
> >> On 30-12-16 13:42, PY5LF wrote:
>
> >>> Hi
>
> >>> We had a low pass over here minutes ago and i felt the keps BY70-1 are
>
> >>> wrong .
>
> >>> I start to hear 25 seconds before . Does anyone feels the same ?
>
> >>> 73
>
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