Jonathan Hofeller, SpaceX: Our Starlink production facility in Seattle is producing 6 satelites a day. We’ve launched 302 to date, w/ another 60 launching at the end of this week.
https://twitter.com/chenry_sn/status/1237013319896240134QuoteJonathan Hofeller, SpaceX: Our Starlink production facility in Seattle is producing 6 satelites a day. We’ve launched 302 to date, w/ another 60 launching at the end of this week.
SpaceX is very secretive about their hardware.One reference point that we do have, is the design of the competing OneWeb satellite, which shares the same spectrum with Starlink. The communications package of OneWeb satellites had been described in great detail in this FCC filing (pdf). Although the document is quite old, the guts of the actual satellites look exactly as one would expect from reading the above description. (See also this video.)Short summary: OneWeb satellite receives Ka-band signal from a gateway using a small steerable dish. This signal is split into 16 bands (labeled as Gateway Uplink 1..16 in the above spectrum diagram). These signals are immediately send down through 16 Ku-band transmitters each feeding one user beam.These 16 oval-shaped beams tile the rectangular area under the satellite, which is about the size of Texas. To avoid interference, the User Downlink frequencies in the adjacent ovals ("cells") are different, but are reused in the cells that are further apart, to enable the same spectrum to serve more than one set of users. There are 8 frequency bands used overall (labeled User Downlink 1..8 in the above diagram.)A similar process occurs on the way from the users to the satellite to the gateway, although the bandwidth is much more narrow (User Uplink 1..4 each have 125 MHz bandwidth, which will be shared for all users in one cell -- about 40000 km2)The satellite serves as a repeater of the analog signals between the gateway and the user -- there is no on-board processing or routing. All the smarts of the system are in the gateway hardware -- it simply has to transmit packets on the right channel for them to arrive to the general area of the intended recipient. User terminals then listen to all the data coming from the satellite, and pick the packets specifically designated for them. The received information also directs user terminal when and on which channel to transmit their Uplink packets, such that the channel can be shared between all users without interference.-------------The Gateway Uplink of Starlink is essentially the same as that of OneWeb system -- it uses the same spectrum, and it uses a small motorized dish to talk to the gateway.Although User Downlink spectrum for Starlink is also the same as for OneWeb, there are differences in how it is used. Where OneWeb uses one fixed antenna for each large cell, Starlink has 4 phased arrays with multiple beams each. What the capabilities of these arrays are, is not known. Potentially, they could afford more efficient area coverage than fixed antennas. Starlink satellites also fly approximately twice lower than OneWeb satellites, and therefore the same bandwidth covers four times smaller area -- providing more bandwidth per user.Otherwise, available spectrum -- especially the gateway uplink -- constrains operation of Starlink satellites in a similar way as we have seen with OneWeb system.
My biggest surprise is OneWeb satellite is just acting as analog repeater without routing and processing, I didn't know this before, I always thought at its core it would be a gigabit router, not sure if this is the same for Starlink.
twitter.com/thesheetztweetz/status/1240258825078353920QuoteSpaceX engineer Jessie Anderson says preliminary results from the Starlink satellite "darkening treatment" test "show a notable reduction" in brightness, but the company has "a couple other ideas that we think could reduce the reflectivity even further."https://twitter.com/thesheetztweetz/status/1240259238141796358QuoteSpaceX says the most promising alternative is a "sun shade," which "would act as a patio umbrella or sun visor" for the satellite, with a test "slated for a future Starlink launch.""All these efforts are ongoing."
SpaceX engineer Jessie Anderson says preliminary results from the Starlink satellite "darkening treatment" test "show a notable reduction" in brightness, but the company has "a couple other ideas that we think could reduce the reflectivity even further."
SpaceX says the most promising alternative is a "sun shade," which "would act as a patio umbrella or sun visor" for the satellite, with a test "slated for a future Starlink launch.""All these efforts are ongoing."
I can’t remember seeing the tension rods on the Starlink stack in such detail before
So we know that SpaceX Starlink effort is headquartered out of the 23020 NE Alder Crest Drive Location from filings ect. I noticed a large building was built next door in the last year. Is it the Starlink Manufacturing line building?
The crux of the argument seems to be the satellites cannot host enough compute to handle the routing themselves...
Quote from: exilon on 09/07/2020 05:59 amThe crux of the argument seems to be the satellites cannot host enough compute to handle the routing themselves...The satellites cannot, but a ground terminal that masses way less than one bird can? Seems like FUD to me.
