>I have failed to find a nice mass or volume number for the satellites.>I've failed to find any source saying the volume for the satellite is between 3m^3 and 6m^3, and not (say) 1m^3.>
Quote from: speedevil on 12/27/2017 04:08 am>I have failed to find a nice mass or volume number for the satellites.>I've failed to find any source saying the volume for the satellite is between 3m^3 and 6m^3, and not (say) 1m^3.>Here ya go....
Quote from: docmordrid on 12/27/2017 05:58 amQuote from: speedevil on 12/27/2017 04:08 am>I have failed to find a nice mass or volume number for the satellites.>I've failed to find any source saying the volume for the satellite is between 3m^3 and 6m^3, and not (say) 1m^3.>Here ya go....I have problems with this. This gives the satellite body dimensions as 4*1.8*1.2m - 8.6m^3, so a completely naive view might be that ~6 satellites might fit inside the fairing.However, Iridium-next satellite dimensions are from one source given as 3.1 m x 2.4 m x 1.5 m - 11.1m^3, and that launched ten. Iridium weighs over twice as much.4*1.8*1.2 is also notably rather larger than a refrigerator (annoyingly, I can find lots of people repeating this claim, but can't find a source at the 2015 announcement, other transcripts of what Elon has said, or ...)If we take 4*1.8*1.2 as gospel, and not unfolded, this is also for example consistent with a pie-wedge shape 4m high, 1.8m wide, with the segments being 1.2m along the outside diameter. this allows fitting 22 into the existing fairing.If the 'size of a refrigerator' is to be believed, then 1.8*1.2*1.2 would about work, with around 40 fitting, assuming rectangular boxes.Either of these would also be about consistent with Iridium satellite density, not way under it.
One topic of recurring speculation is what payloads would need the lift capability of the heavy. Which leads me to a possibly dumb question since I know nothing about satellite architecture. Would it be reasonable for some government agency with a name ending in "A" to take a standard - if there is such a thing - recon sat and add tankage for lots more propellant for station keeping and manuvering? Or are all the systems so interrelated that it would be better to start from scratch building a big honking payload like that? With all the lead time that implies.
The dimensions give a size slightly larger than that of an Iridium sat and therefore only at best 10 will fit in the F9 faring. But that is also 8X that of a refrigerator in size. A refrigerator is more like 2mX.9mX.6m.At 10 the payload weight is only ~5mt and with a longer faring at most with a faring lengthened by 4+m of a count of 15 sats and a payload mass of 7.5mt. Which still is a F9 payload size and not that of a FH.And we are wandering OT for this thread.The Starlink sat discussion should go to this thread:http://forum.nasaspaceflight.com/index.php?topic=44288.new#new
Quote from: oldAtlas_Eguy on 12/27/2017 06:32 pmThe dimensions give a size slightly larger than that of an Iridium sat and therefore only at best 10 will fit in the F9 faring. But that is also 8X that of a refrigerator in size. A refrigerator is more like 2mX.9mX.6m.At 10 the payload weight is only ~5mt and with a longer faring at most with a faring lengthened by 4+m of a count of 15 sats and a payload mass of 7.5mt. Which still is a F9 payload size and not that of a FH.And we are wandering OT for this thread.The Starlink sat discussion should go to this thread:http://forum.nasaspaceflight.com/index.php?topic=44288.new#newThere are perhaps better ways of packing the satellites and deployment structure than used by Iridium. Perhaps by trading satellite mass with deployment structure mass.
For FH, I suspect that they are waiting for the USAF to foot the bill for a longer fairing.
Quote from: AncientU on 12/28/2017 11:23 amFor FH, I suspect that they are waiting for the USAF to foot the bill for a longer fairing.not happening
Quote from: Jim on 12/30/2017 09:15 pmQuote from: AncientU on 12/28/2017 11:23 amFor FH, I suspect that they are waiting for the USAF to foot the bill for a longer fairing.not happeningIf The Air Force wants to launch something that needs a longer fairing they will put out a RFQ for it.If SpaceX wants to bid on it their bid will need to take into account everything they need to do. The Air Force will then decide which of the several bidders gets the launch contract based on RFQ requirements, including but not limited to cost..The AF will allow for reasonable development to be included but they will *not* "pay for" the fairing development. That's on SpaceX's dime alone.
The last thing SpaceX needs is to do one-off projects, even if funded, for the USG.They have StarLink on their mind, and BFR, and everything else is really not that interesting to them.If they need a bigger fairing for StarLink, they'll make one - but they'll make it like they want to, not like the AF wants to.Remember that they want to build an entire BFArchitecture on their own dime - that's a lot more than some extended fairing.
Quote from: meekGee on 12/30/2017 09:52 pmThe last thing SpaceX needs is to do one-off projects, even if funded, for the USG.They have StarLink on their mind, and BFR, and everything else is really not that interesting to them.If they need a bigger fairing for StarLink, they'll make one - but they'll make it like they want to, not like the AF wants to.Remember that they want to build an entire BFArchitecture on their own dime - that's a lot more than some extended fairing.I am quite confident with my opinion that SpaceX intends to to be able to do all DoD missions with the Falcon family. That would include vertical integration and a larger fairing. A 2 year timeframe from contract to launch will enable them to design the capabilities after contract award.Edit: fixed quote