Another strategy implied in the discussion is to ride DoD sensor(s) on commercial satellites. Imagine having several hundred infrared sensing modules installed on SpaceX's Starlink constellation -- say 10% carry the sensor. Then the targeting problem became immensely more difficult for the a-sat wielding opponent. 4,425 targets, only 400 of which are watching you... Vastly (3 orders of magnitude) more resilient that a few SBIRS... and probable vastly cheaper, too.
It wasn't so very long ago (2003) that DOD's DMSP sats were only 830kg. In fact that one (F16) is still in Orbit and operational. It's the packing on all the added multiple sensor packages that have grown the individual weight of the DOD weather sats.
Quote from: oldAtlas_Eguy on 12/08/2017 06:20 pmIt wasn't so very long ago (2003) that DOD's DMSP sats were only 830kg. In fact that one (F16) is still in Orbit and operational. It's the packing on all the added multiple sensor packages that have grown the individual weight of the DOD weather sats.As with much military stuff, quantity has a quality all of its own.Weather observations from half the distance, with several satellites staring constantly, rather than once a day or twice a day 'good' observations as with DMSP.Even with a kilogram only payload on all satellites, you can do really useful global coverage.
Quote from: speedevil on 12/09/2017 01:41 amAs with much military stuff, quantity has a quality all of its own.Weather observations from half the distance, with several satellites staring constantly, rather than once a day or twice a day 'good' observations as with DMSP.Even with a kilogram only payload on all satellites, you can do really useful global coverage.True, but before people get too excited about this idea keep in mind that makes Starlink sats a piece of (partially) military equipment. IOW (from some PoVs) a legitimate military target. If shooting starts that puts them in the firing line.
As with much military stuff, quantity has a quality all of its own.Weather observations from half the distance, with several satellites staring constantly, rather than once a day or twice a day 'good' observations as with DMSP.Even with a kilogram only payload on all satellites, you can do really useful global coverage.
While hosted payloads could be a future source of income, you may want to recall Iridium specifically designed their sats to host other payloads and then had a lot of trouble selling the space, they ended up basically setting up a subsidiary to own a bunch of them.
There may also be secondary outputs of the primary mission - for example GPS has been used as an atmospheric probe by looking at reflections of the signal.Especially over oceans, it's at least plausible that the communications equipment could be used to measure surface roughness and wave motion at very high resolution using active RADAR techniques. If this can be done between satellites especially it would be an extraordinarily powerful technique.'passive' techniques using the ordinary emitted signal may also be possible to derive various interesting things about terrain from snow to vegetation cover.
Quote from: speedevil on 12/09/2017 12:11 pmThere may also be secondary outputs of the primary mission - for example GPS has been used as an atmospheric probe by looking at reflections of the signal.Especially over oceans, it's at least plausible that the communications equipment could be used to measure surface roughness and wave motion at very high resolution using active RADAR techniques. If this can be done between satellites especially it would be an extraordinarily powerful technique.'passive' techniques using the ordinary emitted signal may also be possible to derive various interesting things about terrain from snow to vegetation cover.IIRC GPS has been used for passive sea state monitoring as well.I think there are quite a number of Earth observation tasks that could be handled surprisingly well by quite small packages provided you have the density of a high density constellation.
Quote from: john smith 19 on 12/09/2017 07:09 pmQuote from: speedevil on 12/09/2017 12:11 pmThere may also be secondary outputs of the primary mission - for example GPS has been used as an atmospheric probe by looking at reflections of the signal.Especially over oceans, it's at least plausible that the communications equipment could be used to measure surface roughness and wave motion at very high resolution using active RADAR techniques. If this can be done between satellites especially it would be an extraordinarily powerful technique.'passive' techniques using the ordinary emitted signal may also be possible to derive various interesting things about terrain from snow to vegetation cover.IIRC GPS has been used for passive sea state monitoring as well.I think there are quite a number of Earth observation tasks that could be handled surprisingly well by quite small packages provided you have the density of a high density constellation. I expect this has been said somewhere: Elon is passionately driving a new attitude to science and technology, and their development to save us from global warming, and make us multi-planetary, but the current US administration is trying to cover up science, and restrict circulation of certain results. I suggest SpaceX might gather, and provide high quality data, particularly related to global warming, like ice cover, sea temperature, wave heights, and glacier speed, free and open source, and very likely introduce a philanthropic drive to give more students access to space... after all it may help generate employees, like the Hyperloop competitions!
Quote from: DistantTemple on 12/09/2017 10:45 pmQuote from: john smith 19 on 12/09/2017 07:09 pmQuote from: speedevil on 12/09/2017 12:11 pmThere may also be secondary outputs of the primary mission - for example GPS has been used as an atmospheric probe by looking at reflections of the signal.Especially over oceans, it's at least plausible that the communications equipment could be used to measure surface roughness and wave motion at very high resolution using active RADAR techniques. If this can be done between satellites especially it would be an extraordinarily powerful technique.'passive' techniques using the ordinary emitted signal may also be possible to derive various interesting things about terrain from snow to vegetation cover.IIRC GPS has been used for passive sea state monitoring as well.I think there are quite a number of Earth observation tasks that could be handled surprisingly well by quite small packages provided you have the density of a high density constellation. I expect this has been said somewhere: Elon is passionately driving a new attitude to science and technology, and their development to save us from global warming, and make us multi-planetary, but the current US administration is trying to cover up science, and restrict circulation of certain results. I suggest SpaceX might gather, and provide high quality data, particularly related to global warming, like ice cover, sea temperature, wave heights, and glacier speed, free and open source, and very likely introduce a philanthropic drive to give more students access to space... after all it may help generate employees, like the Hyperloop competitions!I don't think this has been said and may be OT, but I like the idea. However, most of the data types mentioned require specialized payloads that are relatively costly. Some can be done with just imagery, and they will want to sell that service, but can give it to academics and others who are studying climate change.
For hosted payloads. how much wiggling is allowed? If say someone wanted to build up a civilian global remote sensing platform
As concrete examples, the Iridium Boss described two hosted payloads on Iridium NEXT... the system that tracks all aircraft the world over via their transponders, and a second that tracks all sea-going vessels. It is easy to imagine the DoD, for instance being interested in sensor sets that do the same but from passive signatures for non-commercial aircraft and ships. Imaging in various bands could provide this for land and sea activities. Commercially viable imaging could also be real-time traffic reports, natural disaster (fires, earthquakes, hurricanes, snowstorms) evaluation...the list is endless.Think... apps on the internet or your iPhone.