Re: [Starlink] Starlink lost over 200 satellites in two months – tracker data

[Ulrich Speidel <u.speidel@auckland.ac.nz>]

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Yes. The atmosphere doesn't really "end" at a certain altitude, it just 
gets thinner and thinner, which eventually means that the drag on 
spacecraft caused by the remaining air particles up there gets so low 
that the spacecraft can orbit for extended periods of time. But the drag 
isn't zero, and Low Earth Orbit sateIlites such as the Starlink birds 
suffer from some drag. The way to counteract that would normally be 
re-acceleration via small booster engines, but for these to work in 
space, you need fuel aboard the satellite, which will eventually run 
out. As LEOs move faster in denser atmosphere than MEOs and GEOs, that 
puts significant downward pressure on their lifetime (unless, like in 
the case of the ISS, you can refuel).

In the case of Starlink, there is also the minor issue that their 
initial constellation that they started commercial ops with isn't 
ISL-capable, so there may be an incentive here to retire some satellites 
early, perhaps, and fill their orbital slots with more capable birds.

The SpaceX folk on this list might wish to comment?

On 2/10/2023 11:15 pm, Alexandre Petrescu via Starlink wrote:
> One can see the starlink 're-entries' on some re-entry public databases.
>
> On this one from aerospace.org, one can see starlink re-entries
> yesterday, and also 29 sept., 27 sept., etc.
>
> https://aerospace.org/reentries/grid 
> <https://aerospace.org/reentries/grid>
>
> It seems to me - a non expert - that starlink regularly re-enters its
> sats and puts new ones in orbit.  Maybe a starlink sat has a lifetime of
> 2-3 years.
>
> > Object
> > 
> <https://aerospace.org/reentries/grid?field_reentry_sighting_value=All&format_select=table&reentry_timezone_selector=UTC&order=title&sort=asc 
> <https://aerospace.org/reentries/grid?field_reentry_sighting_value=All&format_select=table&reentry_timezone_selector=UTC&order=title&sort=asc>> 
>
> > Mission
> > 
> <https://aerospace.org/reentries/grid?field_reentry_sighting_value=All&format_select=table&reentry_timezone_selector=UTC&order=field_mission&sort=asc 
> <https://aerospace.org/reentries/grid?field_reentry_sighting_value=All&format_select=table&reentry_timezone_selector=UTC&order=field_mission&sort=asc>> 
>
> > Reentry Type
> > 
> <https://aerospace.org/reentries/grid?field_reentry_sighting_value=All&format_select=table&reentry_timezone_selector=UTC&order=field_reentry_type&sort=asc 
> <https://aerospace.org/reentries/grid?field_reentry_sighting_value=All&format_select=table&reentry_timezone_selector=UTC&order=field_reentry_type&sort=asc>> 
>
> > Launched
> > 
> <https://aerospace.org/reentries/grid?field_reentry_sighting_value=All&format_select=table&reentry_timezone_selector=UTC&order=field_launched&sort=asc 
> <https://aerospace.org/reentries/grid?field_reentry_sighting_value=All&format_select=table&reentry_timezone_selector=UTC&order=field_launched&sort=asc>> 
>
> > Predicted Reentry Time
> > 
> <https://aerospace.org/reentries/grid?field_reentry_sighting_value=All&format_select=table&reentry_timezone_selector=UTC&order=field_predicted_reentry_time&sort=desc 
> <https://aerospace.org/reentries/grid?field_reentry_sighting_value=All&format_select=table&reentry_timezone_selector=UTC&order=field_predicted_reentry_time&sort=desc>> 
>
> >
> > STARLINK-1868 (ID 47154) <https://aerospace.org/reentries/47154 
> <https://aerospace.org/reentries/47154>> 
>
> > Launch L15 Payload Nov 25, 2020 Oct 01, 2023 15:39:12 ± 16 hours
> > IUS R/B(1) (ID 19884) <https://aerospace.org/reentries/19884 
> <https://aerospace.org/reentries/19884>> 
> STS
> > 29/TDRS 4 Rocket Body Mar 13, 1989 Sep 30, 2023 12:32:28 ± 7 hours
> > STARLINK-1074 (ID 44957) <https://aerospace.org/reentries/44957 
> <https://aerospace.org/reentries/44957>> 
>
> > Launch L2 Payload Jan 07, 2020 Sep 29, 2023 20:53:28 ± 3 hours
> > STARLINK-5596 (ID 55476) <https://aerospace.org/reentries/55476 
> <https://aerospace.org/reentries/55476>> 
>
> > Launch Group 5-3 Payload Feb 02, 2023 Sep 27, 2023 17:41:11 ± 6 hours
> > STARLINK-2345 (ID 47886) <https://aerospace.org/reentries/47886 
> <https://aerospace.org/reentries/47886>> 
>
> > Launch L21 Payload Mar 14, 2021 Sep 27, 2023 15:58:50 ± 1 hour
> > COSMOS 1124 (ID 11509) <https://aerospace.org/reentries/11509 
> <https://aerospace.org/reentries/11509>> 
> COSMOS
> > 1124 Payload Aug 28, 1979 Sep 27, 2023 00:23:01 ± 1 hour
> > CERES-1 R/B (ID 57796) <https://aerospace.org/reentries/57796 
> <https://aerospace.org/reentries/57796>> 
> TIANQI
> > 21-24 Rocket Body Sep 05, 2023 Sep 25, 2023 06:59:01 ± 1 hour
> > STARLINK-2212 (ID 47779) <https://aerospace.org/reentries/47779 
> <https://aerospace.org/reentries/47779>> 
>
> > Launch L17 Payload Mar 04, 2021 Sep 25, 2023 03:11:43 ± 1 hour
> > STARLINK-1419 (ID 45694) <https://aerospace.org/reentries/45694 
> <https://aerospace.org/reentries/45694>> 
>
> > Launch L7 Payload Jun 04, 2020 Sep 24, 2023 11:01:39 ± 10 hours
> > STARLINK-1026 (ID 44731) <https://aerospace.org/reentries/44731 
> <https://aerospace.org/reentries/44731>> 
>
> > Launch L1 Payload Nov 11, 2019 Sep 22, 2023 22:21:15 ± 3 hours
> > ELECTRON KICK STAGE R/B (ID 55328)
> > <https://aerospace.org/reentries/46929 
> <https://aerospace.org/reentries/46929>> 
> SPACEBEE Rocket Body Nov
> > 20, 2020 Sep 21, 2023 12:57:34 ± 1 hour
> > SL-4 R/B (ID 57863) <https://aerospace.org/reentries/57863 
> <https://aerospace.org/reentries/57863>> 
> SOYUZ
> > MS-24 Rocket Body Sep 15, 2023 Sep 18, 2023 04:58:16 ± 1 hour
> > DELTA 2 R/B(2) (PAM-D) (ID 35754)
> > <https://aerospace.org/reentries/35754 
> <https://aerospace.org/reentries/35754>> 
> USA-206 (GPS IIRM-8) Rocket
> > Body Aug 17, 2009 Sep 18, 2023 04:37:26 ± 1 hour
> > KSLV-1 R/B (ID 39069) <https://aerospace.org/reentries/39069 
> <https://aerospace.org/reentries/39069>> 
>
> > STSAT-2C Rocket Body Jan 30, 2013 Sep 16, 2023 01:21:47 ± 1 hour
> > ELECTRON R/B (ID 44635) <https://aerospace.org/reentries/44635 
> <https://aerospace.org/reentries/44635>> 
>
> > Palisade Rocket Body Oct 17, 2019 Sep 13, 2023 22:07:51 ± 1 hour
> > STARLINK-30042 (ID 55702) <https://aerospace.org/reentries/55702 
> <https://aerospace.org/reentries/55702>> 
>
> > Starlink Group 6-1 Payload Feb 27, 2023 Sep 13, 2023 21:07:58 ± 3
> > hours
> >
>
> Alex
>
> Le 20/09/2023 à 00:55, Dave Taht via Starlink a écrit :
> > The original poster of that to twitter walks it back to 54 since the
> > beginning of the year.
> >
> > On Tue, Sep 19, 2023 at 7:48 AM the keyboard of geoff goodfellow via
> > Starlink <starlink@lists.bufferbloat.net> wrote:
> >
> > ➔➔https://cybernews.com/news/starlink-lost-200-satellites/ 
> <https://cybernews.com/news/starlink-lost-200-satellites>
> >
> > --
> > Geoff.Goodfellow@iconia.com
> > living as The Truth is True
> >
> > _______________________________________________
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> > Starlink@lists.bufferbloat.net
> > https://lists.bufferbloat.net/listinfo/starlink 
> <https://lists.bufferbloat.net/listinfo/starlink>
> >
> >
> >
> > --
> > Oct 30:
> > https://netdevconf.info/0x17/news/the-maestro-and-the-music-bof.html 
> <https://netdevconf.info/0x17/news/the-maestro-and-the-music-bof.html>
> > Dave Täht CSO, LibreQos
> >
> > _______________________________________________
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-- 
****************************************************************
Dr. Ulrich Speidel

School of Computer Science

Room 303S.594 (City Campus)

The University of Auckland
u.speidel@auckland.ac.nz  
http://www.cs.auckland.ac.nz/~ulrich/
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