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Satellite Launches and Retirements
Next generation of "Eutelsat Quantum" Class satellite
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<blockquote data-quote="kevjs" data-source="post: 910061" data-attributes="member: 257344"><p>Quite a few of the satellites in orbit (Astra 2A and Eutelsat 28A being obvious ones) are now operating well beyond there original design lives - I wonder if this is a combination of factors:-</p><p>1) The design life being the period it could operate with it's full complement of transponders in non-inclined orbit (therefore as as neither Eurobird or 2A are operating their full complement of transponders they aren't classed as within design life)</p><p>2) An excess of capacity meaning inclined orbit satellites are less useful - therefore you may as well get an extra 2-3 years DTH use out of it rather than 5-6 years of lightly used SNG use)</p><p>3) The stronger signals they put out allowing them to reduce station keeping fuel burns - if you can save 4% a year (2 weeks ish) over a ten year design life that gives you another half year - possibly compensated by slightly increasing power when at the fringes</p><p>4) The newer generation equipment being more reliable in service than originally planned for therefore the transponders lasting longer (also modern craft having more spares - see Astra 1A having 16 with 0 spares, Astra 1C having 18 + 3 IIRC, Astra 2B having 28 + 4 with most of it's life spent operating only ~20 - i.e. 14 spares) meaning it becomes fuel limited rather than transponder limited</p><p>5) The design life being conservative and how long insurance (etc) lasts*</p><p></p><p>In the latter case we know that as stuff gets old it starts to break and from what we know both Astra and Eutelsat have different plans of action at 28.2'E</p><p>i.e. Astra has Astra 2C ready and waiting saving it's transponders (even though the footprint is suboptimal) and extra capacity is being held back on 2E and 2F.</p><p>Eutelsat have various craft which are lightly used so if Eurobird was to fail they can shunt another one across (see Eutelsat 48B - 28<img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite6" alt=":cool:" title="Cool :cool:" loading="lazy" data-shortname=":cool:" /> with non-DTH stuff being shuffled around (e.g. if they were a bit short of SNG stuff after losing 48B they could use Hotbird, 36'E etc if the other options were unviable for a specific customer). Eurobird's rates are known to be cheaper and presumably part of this is the expectation that a catastrophic failure would result in a longer loss of service than Astra (although it wouldn't surprise me if Arqiva had an agreement with Astra to use "spare" capacity should the need arise with the obvious delay in Sky and Freesat boxes seeing the services in there new homes).</p><p></p><p>* So taking Eurobird and 2A as examples - if those were to have failed in 2005 then the insurance will probably have covered any compensation the operators needed to pay out, but now it may not do. Therefore SES will have done one or more of a number of things, such as Kept the rates the same / reduced them on the understanding of a failure of 2A then capacity would be forthcoming on a co-located satellite within a few minutes / hours; Continued to charge the same rates, but in the event of failure just pay out; Come to an agreement with the insurer to review the performance of the craft more frequently and adjust the premiums/agreement as required. </p><p></p><p>With regards to point 1 Eutelsat / Astra will have been monitoring them throughout their lives and have a good feel as to how long they will last (and what their future plans are). With a satellite like Eurobird that has 30 transponders (including six spares) using it at a position like 28.'5E (where only 8 can be used) some of these limitations may be less relevant. (e.g. if it still has 16 working and based on usage they are expecting one failure a year then the fuel becomes the limiting factor.</p><p></p><p>It's obviously in Astra's interest to minimise they usage of their new craft (no point burning out all the transponders now meaning it becomes a bit useless at EOL even though it's got a few more years fuel).</p><p></p><p>IIRC the three limiting factors for a satellites life operating at maximum power, with a full complement of transponders in geostationary orbit are:-</p><p>1) Fuel - once it's gone it's gone</p><p>2) Transponders - once they fail (typically start failing after ~10 years) you're onto the spares</p><p>and also</p><p>3) Solar panel degradation (i.e. scratches and space dust reducing the amount of power generated)</p><p>4) Other wear and tear (i.e. heat/cooling cycle).</p><p></p><p>Therefore if the fuel can be used as sparingly as possible, and you have an excess of spare transponders you can keep the satellite going until the fuel runs out provided the rest of it doesn't start to fail. The solar panel degradation becomes immaterial towards EOL as there are fewer transponders to power (IIRC Astra 1A was designed to have only 14 operational by 1999 but didn't have any spares so that was to be expected - and even if all 16 were still working* then the solar panel degradation would have meant two being turned off).</p><p>* IIRC two had gone faulty pretty early on and were taken over by Astra 1C.</p></blockquote><p></p>
[QUOTE="kevjs, post: 910061, member: 257344"] Quite a few of the satellites in orbit (Astra 2A and Eutelsat 28A being obvious ones) are now operating well beyond there original design lives - I wonder if this is a combination of factors:- 1) The design life being the period it could operate with it's full complement of transponders in non-inclined orbit (therefore as as neither Eurobird or 2A are operating their full complement of transponders they aren't classed as within design life) 2) An excess of capacity meaning inclined orbit satellites are less useful - therefore you may as well get an extra 2-3 years DTH use out of it rather than 5-6 years of lightly used SNG use) 3) The stronger signals they put out allowing them to reduce station keeping fuel burns - if you can save 4% a year (2 weeks ish) over a ten year design life that gives you another half year - possibly compensated by slightly increasing power when at the fringes 4) The newer generation equipment being more reliable in service than originally planned for therefore the transponders lasting longer (also modern craft having more spares - see Astra 1A having 16 with 0 spares, Astra 1C having 18 + 3 IIRC, Astra 2B having 28 + 4 with most of it's life spent operating only ~20 - i.e. 14 spares) meaning it becomes fuel limited rather than transponder limited 5) The design life being conservative and how long insurance (etc) lasts* In the latter case we know that as stuff gets old it starts to break and from what we know both Astra and Eutelsat have different plans of action at 28.2'E i.e. Astra has Astra 2C ready and waiting saving it's transponders (even though the footprint is suboptimal) and extra capacity is being held back on 2E and 2F. Eutelsat have various craft which are lightly used so if Eurobird was to fail they can shunt another one across (see Eutelsat 48B - 28B) with non-DTH stuff being shuffled around (e.g. if they were a bit short of SNG stuff after losing 48B they could use Hotbird, 36'E etc if the other options were unviable for a specific customer). Eurobird's rates are known to be cheaper and presumably part of this is the expectation that a catastrophic failure would result in a longer loss of service than Astra (although it wouldn't surprise me if Arqiva had an agreement with Astra to use "spare" capacity should the need arise with the obvious delay in Sky and Freesat boxes seeing the services in there new homes). * So taking Eurobird and 2A as examples - if those were to have failed in 2005 then the insurance will probably have covered any compensation the operators needed to pay out, but now it may not do. Therefore SES will have done one or more of a number of things, such as Kept the rates the same / reduced them on the understanding of a failure of 2A then capacity would be forthcoming on a co-located satellite within a few minutes / hours; Continued to charge the same rates, but in the event of failure just pay out; Come to an agreement with the insurer to review the performance of the craft more frequently and adjust the premiums/agreement as required. With regards to point 1 Eutelsat / Astra will have been monitoring them throughout their lives and have a good feel as to how long they will last (and what their future plans are). With a satellite like Eurobird that has 30 transponders (including six spares) using it at a position like 28.'5E (where only 8 can be used) some of these limitations may be less relevant. (e.g. if it still has 16 working and based on usage they are expecting one failure a year then the fuel becomes the limiting factor. It's obviously in Astra's interest to minimise they usage of their new craft (no point burning out all the transponders now meaning it becomes a bit useless at EOL even though it's got a few more years fuel). IIRC the three limiting factors for a satellites life operating at maximum power, with a full complement of transponders in geostationary orbit are:- 1) Fuel - once it's gone it's gone 2) Transponders - once they fail (typically start failing after ~10 years) you're onto the spares and also 3) Solar panel degradation (i.e. scratches and space dust reducing the amount of power generated) 4) Other wear and tear (i.e. heat/cooling cycle). Therefore if the fuel can be used as sparingly as possible, and you have an excess of spare transponders you can keep the satellite going until the fuel runs out provided the rest of it doesn't start to fail. The solar panel degradation becomes immaterial towards EOL as there are fewer transponders to power (IIRC Astra 1A was designed to have only 14 operational by 1999 but didn't have any spares so that was to be expected - and even if all 16 were still working* then the solar panel degradation would have meant two being turned off). * IIRC two had gone faulty pretty early on and were taken over by Astra 1C. [/QUOTE]
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