From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-il1-x135.google.com (mail-il1-x135.google.com [IPv6:2607:f8b0:4864:20::135]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 4EF943B2A4 for ; Sat, 8 Jul 2023 10:07:02 -0400 (EDT) Received: by mail-il1-x135.google.com with SMTP id e9e14a558f8ab-3456fda4ed1so12372755ab.0 for ; Sat, 08 Jul 2023 07:07:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1688825221; x=1691417221; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=4V8/3d45F7JO9YaELz/t81rDqMkfVFwuHXJWAehBKOo=; b=fyyLVJP3lZw9jfzhUh/A0I1jPTVadtA7j5+yq/qHY2NHGXDPxdvP9+pNFzLfXegUTn 5hoP3SgiBy9+lph4Y9iHg5lUjY0sqwdpCJAFh5uFqY/Po5BY/APvBHrPhRn1wg1R+Pxr B4Dv2L80vahelmI8Am+nAJCXdGWfxoRQKpbZiuD/GmvCiA0Rr/0hyISLc+AlOKh1FFSu WgxYkmVjr7L2dZNB9wp1alW7nbJdgw7w9buC5UCfmjefJ3DmwYa+2PDJULVkCKbBd0JH /VS0GoXCecLmZNCE8lAa53IEBFPNIhSDQNyY1gERvHaa00EnufpFzukzy0Q0mSdm0YcJ /FiA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688825221; x=1691417221; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=4V8/3d45F7JO9YaELz/t81rDqMkfVFwuHXJWAehBKOo=; b=DcRPlkWt7IkSyAr1s1dyeI12jYbojPNK8nAM/emGB79pg4+PjsSkXdcQDHWM/GkDXH joLrTHDFarJT6NbQxYIm7ijdrNM79v9dUD7ipmgES3/PbklnlTJCeILO2238NVue0++/ JnlSuMXMeVYyK2PEC9MdiBd0PzwfNGE8XmBKYMOs9tMG5IRRDf85bQu7L2K016Sx/vOZ bSWvSByvJcSTbPad/rq4bIzmMiBYvD2PSJrglDFSLjblcgATuviMzJO7mMY6XodxJooM Ukru0qFUhXISJV4Zs/YbZ7YxzrL+2hVTpEwTvMlZadnv+0vX81QXcj+JPwCNlMqp+UHt 2syA== X-Gm-Message-State: ABy/qLbGT70V1rOtU4affZsMYcishBqMlbt8hmB3ZzIYTX4djhU8yox/ kbqgzUIy6YNakfejfSPU8VvLS0kJhFILLZMH/n0= X-Google-Smtp-Source: APBJJlGOVQTmye4p7s3UYPuImwcEF0sZ4xGXjXzXiAF1pNvLy5BlYO/4vdKXeF66thSQTuG0oBGHjUMKwEBxcVv47NE= X-Received: by 2002:a92:dd11:0:b0:345:dadc:28d6 with SMTP id n17-20020a92dd11000000b00345dadc28d6mr7809023ilm.32.1688825221479; Sat, 08 Jul 2023 07:07:01 -0700 (PDT) MIME-Version: 1.0 References: <114eabbd-cf5b-1c08-8226-fbf53455d9ea@falco.ca> <6p3296pr-96n3-8p77-ps68-25155r16o365@ynat.uz> <32d09d76-7aa6-a469-9539-d02a9fa9c7f3@gmail.com> In-Reply-To: From: Dave Taht Date: Sat, 8 Jul 2023 08:06:48 -0600 Message-ID: To: Ulrich Speidel Cc: "blakangel@gmail.com" , David Lang , "starlink@lists.bufferbloat.net" , Daniel AJ Sokolov Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Starlink] orbital maneuvers 12 per sat in the last 6 months X-BeenThere: starlink@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: "Starlink has bufferbloat. Bad." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 08 Jul 2023 14:07:02 -0000 I think perhaps tracking potential energy transfer from a collision would be a good baseline? a BB, moving at 17kph relative to the impact packs quite a wallop. One at 5kph, far less so. Still, that is much smaller than a centimeter. A cosmic ray impact on the wrong transistor can be impactful in different w= ays. A followon thought is possibly, as satellites are de-orbited would it be possible to take some debris down with them in some way? On Fri, Jul 7, 2023 at 4:28=E2=80=AFPM Ulrich Speidel via Starlink wrote: > > Now there is the misuse of the expression "exponentially" in cases when p= eople just mean "a bit faster than before". If you have a time series 1, 2,= 4, 6, 8 then you could claim that it's exponential because the first three= terms double each time, yet the last four terms could be used to claim tha= t it's linear. > > Plus, exponential growth doesn't necessarily mean fast growth. Your 2020 = term deposit for 5 years at 1% interest rate with interest reinvested sees = your money growing exponentially, too. This is perhaps why decision-makers = from the economics sphere tend to get caught out be fast exponential growth= (the sort of growth us science and engineering folk tend to think of). > > Beyond that: I'm not sure that I can make much of orbital maneuver number= s. Even GEO sats - for which collision probability is very low - undertake = regular corrective maneuvers for station-keeping. For anything further down= , a maneuver could be a short-term evasive action, a longer term orbit inje= ction or change maneuver, or corrective action to any of these. > > Each maneuver uses some of the satellite's propellant reserve. As a gener= al rule, a maneuver executed over a longer period of time is more fuel effi= cient: A small change in a satellite's trajectory now can lead to a large c= hange down the time axis, with very little propellant use - think Starlink = satellites transitioning from launch train to final station over months. Ma= king small corrective adjustments to this over time might bring the total n= umber of maneuvers up, too. Conversely, large short-term corrections dip in= to fuel reserves, which can impact on service life. So you'd really need to= ask which sort of maneuvers these are, and how much each maneuver costs in= terms of service life. > > -- > **************************************************************** > Dr. Ulrich Speidel > > Department of Computer Science > > Room 303S.594 > Ph: (+64-9)-373-7599 ext. 85282 > > The University of Auckland > u.speidel@auckland.ac.nz > http://www.cs.auckland.ac.nz/~ulrich/ > **************************************************************** > ________________________________ > From: Starlink on behalf of Davi= d Lang via Starlink > Sent: Friday, July 7, 2023 6:02 PM > To: blakangel@gmail.com > Cc: starlink@lists.bufferbloat.net ; Dani= el AJ Sokolov > Subject: Re: [Starlink] orbital maneuvers 12 per sat in the last 6 months > > they have been filling shells (altitude sets), so it makes sense for the = numbers > to have been going up. > > we'll have to see if they keep going up as much as they move on to differ= ent > altitude shells. > > David Lang > > On Thu, 6 Jul 2023, blakangel@gmail.com wrote: > > > I think the main point of the article is that the amount of maneuvers n= eeded > > is currently increasing exponentially: "It's been doubling every six mo= nths, > > and the problem with exponential trends is that they get to very large > > numbers very quickly." I'm wondering if they are not taking into accoun= t the > > massive amount of satellites that have been launched since the previous= six > > month report. > > > > I found the semi-annual reports filed w/ the fcc: > > https://licensing.fcc.gov/myibfs/download.do?attachment_key=3D23204343 = and > > https://licensing.fcc.gov/myibfs/download.do?attachment_key=3D23204338 = for gen > > 1 and gen 2 constellations. > > > > Still reading them and haven't found the older ones yet to compare. > > > > > > David Lang via Starlink wrote on 7/6/2023 9:49 PM: > > > >> some people are assuming that more satellites launched will mean more > >> maneuvers needed (not recognizing that what matters is only the things= at > >> the same altitude) > >> > >> plus, it's a scary large number :-) > >> > >> David Lang > >> > >> On Thu, 6 Jul 2023, Daniel AJ Sokolov via Starlink wrote: > >> > >>> On 7/6/23 17:54, Dave Taht via Starlink wrote: > >>>> > >>> https://www.space.com/starlink-satellite-conjunction-increase-threate= ns-space-sustainability > >>>> > >>>> I am under the impression that each sat is capable of about 500 over > >>>> the satellite's lifetime. I am curious as to what they are avoiding. > >>> > >>> Assuming your number of 500 is correct, I don't see any worry here. 1= 2 > >>> moves in 6 months makes 492 in 20.5 years. That is less than 500 and > >>> beyond the lifetime expectation of the satellite anyway. > >>> > >>> A I missing something? > >>> Daniel AJ > >>> _______________________________________________ > >>> Starlink mailing list > >>> Starlink@lists.bufferbloat.net > >>> https://lists.bufferbloat.net/listinfo/starlink > >>> > >> _______________________________________________ > >> Starlink mailing list > >> Starlink@lists.bufferbloat.net > >> https://lists.bufferbloat.net/listinfo/starlink > > > > > _______________________________________________ > Starlink mailing list > Starlink@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/starlink --=20 Podcast: https://www.linkedin.com/feed/update/urn:li:activity:7058793910227= 111937/ Dave T=C3=A4ht CSO, LibreQos