Decommissioned SVN24 (PRN24) now exhibits an orbital period of 750.55
minutes. That's indicative of its being boosted to a disposal orbit.

The satellite experienced a reaction wheel failure. It was launched
on 04 July 1991.

--- CHAS

On 2011-11-24 20:23 , HIPAR wrote:
> Decommissioned SVN24 (PRN24) now exhibits an orbital period of 750.55
> minutes. That's indicative of its being boosted to a disposal orbit.
>
> The satellite experienced a reaction wheel failure. It was launched
> on 04 July 1991.

What's the disposal method? Frig the orbit into re-entry?


--
"I see!" said the blind man as he picked up his hammer and saw.

On Nov 25, 11:33*am, Alan Browne <alan.bro...@FreelunchVideotron.ca>
wrote:
> On 2011-11-24 20:23 , HIPAR wrote:
>
> > Decommissioned SVN24 (PRN24) now exhibits an orbital period of 750.55
> > minutes. *That's indicative of its being boosted to a disposal orbit.
>
> > The satellite experienced a reaction wheel failure. *It was launched
> > on 04 July 1991.
>
> What's the disposal method? *Frig the orbit into re-entry?
>
> --
> "I see!" said the blind man as he picked up his hammer and saw.

Boost to a higher orbit where it is out of the way.

On 2011-11-26 09:44 , (E-Mail Removed) wrote:
> On Nov 25, 11:33 am, Alan Browne<alan.bro...@FreelunchVideotron.ca>
> wrote:
>> On 2011-11-24 20:23 , HIPAR wrote:
>>
>>> Decommissioned SVN24 (PRN24) now exhibits an orbital period of 750.55
>>> minutes. That's indicative of its being boosted to a disposal orbit.
>>
>>> The satellite experienced a reaction wheel failure. It was launched
>>> on 04 July 1991.
>>
>> What's the disposal method? Frig the orbit into re-entry?
>>
>> --
>> "I see!" said the blind man as he picked up his hammer and saw.
>
> Boost to a higher orbit where it is out of the way.

Oh. I suppose there's not much between the GPS shell and the
geo-stat/sync shell. But eventually it will come crashing. Wonder why
they don't just get it over with.

--
"I see!" said the blind man as he picked up his hammer and saw.

On Nov 26, 9:56*am, Alan Browne <alan.bro...@FreelunchVideotron.ca>
wrote:
> On 2011-11-26 09:44 , s_an...@comcast.net wrote:
>
>
>
>
>
>
>
>
>
> > On Nov 25, 11:33 am, Alan Browne<alan.bro...@FreelunchVideotron.ca>
> > wrote:
> >> On 2011-11-24 20:23 , HIPAR wrote:
>
> >>> Decommissioned SVN24 (PRN24) now exhibits an orbital period of 750.55
> >>> minutes. *That's indicative of its being boosted to a disposal orbit.
>
> >>> The satellite experienced a reaction wheel failure. *It was launched
> >>> on 04 July 1991.
>
> >> What's the disposal method? *Frig the orbit into re-entry?
>
> >> --
> >> "I see!" said the blind man as he picked up his hammer and saw.
>
> > Boost to a higher orbit where it is out of the way.
>
> Oh. *I suppose there's not much between the GPS shell and the
> geo-stat/sync shell. *But eventually it will come crashing. *Wonder why
> they don't just get it over with.
>
> --
> "I see!" said the blind man as he picked up his hammer and saw.

There's not enough propellant aboard to deorbit. I suspect they
deplete what's left using the maneuvering thrusters to boost the
orbit. A graveyard orbit isn't completely stable. Eventually, those
dead satellites are expected to encroach into the constellation
presenting a risk of collision.

The process isn't precise. Disposal orbital periods vary over a
fairly wide range.

--- CHAS

On 2011-11-26 16:47 , HIPAR wrote:
> On Nov 26, 9:56 am, Alan Browne<alan.bro...@FreelunchVideotron.ca>
> wrote:
>> On 2011-11-26 09:44 , s_an...@comcast.net wrote:
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>> On Nov 25, 11:33 am, Alan Browne<alan.bro...@FreelunchVideotron.ca>
>>> wrote:
>>>> On 2011-11-24 20:23 , HIPAR wrote:
>>
>>>>> Decommissioned SVN24 (PRN24) now exhibits an orbital period of 750.55
>>>>> minutes. That's indicative of its being boosted to a disposal orbit.
>>
>>>>> The satellite experienced a reaction wheel failure. It was launched
>>>>> on 04 July 1991.
>>
>>>> What's the disposal method? Frig the orbit into re-entry?
>>
>>>> --
>>>> "I see!" said the blind man as he picked up his hammer and saw.
>>
>>> Boost to a higher orbit where it is out of the way.
>>
>> Oh. I suppose there's not much between the GPS shell and the
>> geo-stat/sync shell. But eventually it will come crashing. Wonder why
>> they don't just get it over with.
>>
>> --
>> "I see!" said the blind man as he picked up his hammer and saw.
>
> There's not enough propellant aboard to deorbit. I suspect they
> deplete what's left using the maneuvering thrusters to boost the
> orbit. A graveyard orbit isn't completely stable. Eventually, those
> dead satellites are expected to encroach into the constellation
> presenting a risk of collision.
>
> The process isn't precise. Disposal orbital periods vary over a
> fairly wide range.
>
> --- CHAS

If you can boost the orbit you can certainly decelerate the vehicle in
its orbit. That would guarantee re-entry. Just slow it down by a tiny
amount and it will not ever hit another GPS sat, and will definitely
start coming down in a spiral eventually re-entering. 0.01% of v would
be enough. There must be some other issue.

--
"I see!" said the blind man as he picked up his hammer and saw.

On 26 Nov, 23:49, Alan Browne <alan.bro...@FreelunchVideotron.ca>
wrote:
> On 2011-11-26 16:47 , HIPAR wrote:
>
>
>
>
>
>
>
>
>
> > On Nov 26, 9:56 am, Alan Browne<alan.bro...@FreelunchVideotron.ca>
> > wrote:
> >> On 2011-11-26 09:44 , s_an...@comcast.net wrote:
>
> >>> On Nov 25, 11:33 am, Alan Browne<alan.bro...@FreelunchVideotron.ca>
> >>> wrote:
> >>>> On 2011-11-24 20:23 , HIPAR wrote:
>
> >>>>> Decommissioned SVN24 (PRN24) now exhibits an orbital period of 750.55
> >>>>> minutes. *That's indicative of its being boosted to a disposal orbit.
>
> >>>>> The satellite experienced a reaction wheel failure. *It was launched
> >>>>> on 04 July 1991.
>
> >>>> What's the disposal method? *Frig the orbit into re-entry?
>
> >>>> --
> >>>> "I see!" said the blind man as he picked up his hammer and saw.
>
> >>> Boost to a higher orbit where it is out of the way.
>
> >> Oh. *I suppose there's not much between the GPS shell and the
> >> geo-stat/sync shell. *But eventually it will come crashing. *Wonder why
> >> they don't just get it over with.
>
> >> --
> >> "I see!" said the blind man as he picked up his hammer and saw.
>
> > There's not enough propellant aboard to deorbit. *I suspect they
> > deplete what's left using the maneuvering thrusters to boost the
> > orbit. *A graveyard orbit isn't completely stable. *Eventually, those
> > dead satellites are expected to encroach into the constellation
> > presenting a risk of collision.
>
> > The process isn't precise. *Disposal orbital periods vary over a
> > fairly wide range.
>
> > --- *CHAS
>
> If you can boost the orbit you can certainly decelerate the vehicle in
> its orbit. *That would guarantee re-entry. *Just slow it down by a tiny
> amount and it will not ever hit another GPS sat, and will definitely
> start coming down in a spiral eventually re-entering. *0.01% of v would
> be enough. *There must be some other issue.

Slowing it down, since it starts from a quite high orbit, means that
it will circulate for very long time from it's orbit into lower
orbits...
And you really can't predict where it will go. Once it approaces the
crowded LEO, it would a a big problem for years before it re-enters.

On 2011-11-29 12:23 , claudegps wrote:
> On 26 Nov, 23:49, Alan Browne<alan.bro...@FreelunchVideotron.ca>
> wrote:
>> On 2011-11-26 16:47 , HIPAR wrote:
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>> On Nov 26, 9:56 am, Alan Browne<alan.bro...@FreelunchVideotron.ca>
>>> wrote:
>>>> On 2011-11-26 09:44 , s_an...@comcast.net wrote:
>>
>>>>> On Nov 25, 11:33 am, Alan Browne<alan.bro...@FreelunchVideotron.ca>
>>>>> wrote:
>>>>>> On 2011-11-24 20:23 , HIPAR wrote:
>>
>>>>>>> Decommissioned SVN24 (PRN24) now exhibits an orbital period of 750.55
>>>>>>> minutes. That's indicative of its being boosted to a disposal orbit.
>>
>>>>>>> The satellite experienced a reaction wheel failure. It was launched
>>>>>>> on 04 July 1991.
>>
>>>>>> What's the disposal method? Frig the orbit into re-entry?
>>
>>>>>> --
>>>>>> "I see!" said the blind man as he picked up his hammer and saw.
>>
>>>>> Boost to a higher orbit where it is out of the way.
>>
>>>> Oh. I suppose there's not much between the GPS shell and the
>>>> geo-stat/sync shell. But eventually it will come crashing. Wonder why
>>>> they don't just get it over with.
>>
>>>> --
>>>> "I see!" said the blind man as he picked up his hammer and saw.
>>
>>> There's not enough propellant aboard to deorbit. I suspect they
>>> deplete what's left using the maneuvering thrusters to boost the
>>> orbit. A graveyard orbit isn't completely stable. Eventually, those
>>> dead satellites are expected to encroach into the constellation
>>> presenting a risk of collision.
>>
>>> The process isn't precise. Disposal orbital periods vary over a
>>> fairly wide range.
>>
>>> --- CHAS
>>
>> If you can boost the orbit you can certainly decelerate the vehicle in
>> its orbit. That would guarantee re-entry. Just slow it down by a tiny
>> amount and it will not ever hit another GPS sat, and will definitely
>> start coming down in a spiral eventually re-entering. 0.01% of v would
>> be enough. There must be some other issue.
>
> Slowing it down, since it starts from a quite high orbit, means that
> it will circulate for very long time from it's orbit into lower
> orbits...
> And you really can't predict where it will go. Once it approaces the
> crowded LEO, it would a a big problem for years before it re-enters.

I know. But it's going to come down eventually. So the operators
should scratch their noggins and compute the dV that gets it down with
the least risk (probability of hit) to other satellites. There is no 0
risk - and that includes boosting its orbit where it will, in any case,
eventually begin a long re-entry. Indeed at that time, with all its
fuel spent or perhaps its computers dead of failure, there will be no
means to optimize the descent rate to protect other satellites.

The chances of it hitting an other object are very low in any case -
more likely to hit some debris than an operating satellite.

--
"I see!" said the blind man as he picked up his hammer and saw.

On 29 Nov, 18:54, Alan Browne <alan.bro...@FreelunchVideotron.ca>
wrote:
> On 2011-11-29 12:23 , claudegps wrote:
>
>
>
>
>
>
>
>
>
> > On 26 Nov, 23:49, Alan Browne<alan.bro...@FreelunchVideotron.ca>
> > wrote:
> >> On 2011-11-26 16:47 , HIPAR wrote:
>
> >>> On Nov 26, 9:56 am, Alan Browne<alan.bro...@FreelunchVideotron.ca>
> >>> wrote:
> >>>> On 2011-11-26 09:44 , s_an...@comcast.net wrote:
>
> >>>>> On Nov 25, 11:33 am, Alan Browne<alan.bro...@FreelunchVideotron.ca>
> >>>>> wrote:
> >>>>>> On 2011-11-24 20:23 , HIPAR wrote:
>
> >>>>>>> Decommissioned SVN24 (PRN24) now exhibits an orbital period of 750.55
> >>>>>>> minutes. *That's indicative of its being boosted to a disposal orbit.
>
> >>>>>>> The satellite experienced a reaction wheel failure. *It was launched
> >>>>>>> on 04 July 1991.
>
> >>>>>> What's the disposal method? *Frig the orbit into re-entry?
>
> >>>>>> --
> >>>>>> "I see!" said the blind man as he picked up his hammer and saw.
>
> >>>>> Boost to a higher orbit where it is out of the way.
>
> >>>> Oh. *I suppose there's not much between the GPS shell and the
> >>>> geo-stat/sync shell. *But eventually it will come crashing. *Wonder why
> >>>> they don't just get it over with.
>
> >>>> --
> >>>> "I see!" said the blind man as he picked up his hammer and saw.
>
> >>> There's not enough propellant aboard to deorbit. *I suspect they
> >>> deplete what's left using the maneuvering thrusters to boost the
> >>> orbit. *A graveyard orbit isn't completely stable. *Eventually, those
> >>> dead satellites are expected to encroach into the constellation
> >>> presenting a risk of collision.
>
> >>> The process isn't precise. *Disposal orbital periods vary over a
> >>> fairly wide range.
>
> >>> --- *CHAS
>
> >> If you can boost the orbit you can certainly decelerate the vehicle in
> >> its orbit. *That would guarantee re-entry. *Just slow it down by atiny
> >> amount and it will not ever hit another GPS sat, and will definitely
> >> start coming down in a spiral eventually re-entering. *0.01% of v would
> >> be enough. *There must be some other issue.
>
> > Slowing it down, since it starts from a quite high orbit, means that
> > it will circulate for very long time from it's orbit into lower
> > orbits...
> > And you really can't predict where it will go. Once it approaces the
> > crowded LEO, it would a a big problem for years before it re-enters.
>
> I know. *But it's going to come down eventually. *So the operators
> should scratch their noggins and compute the dV that gets it down with
> the least risk (probability of hit) to other satellites. *There is no 0
> risk - and that includes boosting its orbit where it will, in any case,
> eventually begin a long re-entry. *Indeed at that time, with all its
> fuel spent or perhaps its computers dead of failure, there will be no
> means to optimize the descent rate to protect other satellites.

Ok, but the dv required for deorbiting is much higher that the one
required for parking.
Considering that the fuel needed for the parking orbit is about 3
months of stationkeeping, the deorbit may cost (in term of operational
life) many moths (even years)
This would require a complete different approach to the satellite
design rules.

On 2011-12-01 08:15 , claudegps wrote:
> On 29 Nov, 18:54, Alan Browne<alan.bro...@FreelunchVideotron.ca>
> wrote:
>> On 2011-11-29 12:23 , claudegps wrote:
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>> On 26 Nov, 23:49, Alan Browne<alan.bro...@FreelunchVideotron.ca>
>>> wrote:
>>>> On 2011-11-26 16:47 , HIPAR wrote:
>>
>>>>> On Nov 26, 9:56 am, Alan Browne<alan.bro...@FreelunchVideotron.ca>
>>>>> wrote:
>>>>>> On 2011-11-26 09:44 , s_an...@comcast.net wrote:
>>
>>>>>>> On Nov 25, 11:33 am, Alan Browne<alan.bro...@FreelunchVideotron.ca>
>>>>>>> wrote:
>>>>>>>> On 2011-11-24 20:23 , HIPAR wrote:
>>
>>>>>>>>> Decommissioned SVN24 (PRN24) now exhibits an orbital period of 750.55
>>>>>>>>> minutes. That's indicative of its being boosted to a disposal orbit.
>>
>>>>>>>>> The satellite experienced a reaction wheel failure. It was launched
>>>>>>>>> on 04 July 1991.
>>
>>>>>>>> What's the disposal method? Frig the orbit into re-entry?
>>
>>>>>>>> --
>>>>>>>> "I see!" said the blind man as he picked up his hammer and saw.
>>
>>>>>>> Boost to a higher orbit where it is out of the way.
>>
>>>>>> Oh. I suppose there's not much between the GPS shell and the
>>>>>> geo-stat/sync shell. But eventually it will come crashing. Wonder why
>>>>>> they don't just get it over with.
>>
>>>>>> --
>>>>>> "I see!" said the blind man as he picked up his hammer and saw.
>>
>>>>> There's not enough propellant aboard to deorbit. I suspect they
>>>>> deplete what's left using the maneuvering thrusters to boost the
>>>>> orbit. A graveyard orbit isn't completely stable. Eventually, those
>>>>> dead satellites are expected to encroach into the constellation
>>>>> presenting a risk of collision.
>>
>>>>> The process isn't precise. Disposal orbital periods vary over a
>>>>> fairly wide range.
>>
>>>>> --- CHAS
>>
>>>> If you can boost the orbit you can certainly decelerate the vehicle in
>>>> its orbit. That would guarantee re-entry. Just slow it down by a tiny
>>>> amount and it will not ever hit another GPS sat, and will definitely
>>>> start coming down in a spiral eventually re-entering. 0.01% of v would
>>>> be enough. There must be some other issue.
>>
>>> Slowing it down, since it starts from a quite high orbit, means that
>>> it will circulate for very long time from it's orbit into lower
>>> orbits...
>>> And you really can't predict where it will go. Once it approaces the
>>> crowded LEO, it would a a big problem for years before it re-enters.
>>
>> I know. But it's going to come down eventually. So the operators
>> should scratch their noggins and compute the dV that gets it down with
>> the least risk (probability of hit) to other satellites. There is no 0
>> risk - and that includes boosting its orbit where it will, in any case,
>> eventually begin a long re-entry. Indeed at that time, with all its
>> fuel spent or perhaps its computers dead of failure, there will be no
>> means to optimize the descent rate to protect other satellites.
>
> Ok, but the dv required for deorbiting is much higher that the one
> required for parking.

The dV to deorbit is practically as small as you want it to be. Point
thrusters against it's V and burb a couple times. It will de-orbit.
Points for style by getting it down in a way that reduces probability of
collision.

> Considering that the fuel needed for the parking orbit is about 3
> months of stationkeeping, the deorbit may cost (in term of operational
> life) many moths (even years)
> This would require a complete different approach to the satellite
> design rules.

The satellite is essentially useless. The GPS signal is off. It is
space junk. Don't park junk.


--
"I see!" said the blind man as he picked up his hammer and saw.