Author Topic: Starlink : Hardware Design / Manufacturing  (Read 60158 times)

Offline FutureSpaceTourist

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Re: Starlink : Hardware Design / Manufacturing
« Reply #20 on: 03/09/2020 02:11 pm »
https://twitter.com/chenry_sn/status/1237013319896240134

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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.

Offline thirtyone

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Re: Starlink : Hardware Design / Manufacturing
« Reply #21 on: 03/09/2020 05:58 pm »
https://twitter.com/chenry_sn/status/1237013319896240134

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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.

Anyone know if the discussion that included Jonathan Hofeller is available to stream somewhere? Sounds like a lot of juicy stuff about Starlink and OneWeb.

Offline Rondaz

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Re: Starlink : Hardware Design / Manufacturing
« Reply #22 on: 03/10/2020 02:25 am »
OneWeb, SpaceX optimistic about cheap user terminals..

by Caleb Henry — March 9, 2020

https://spacenews.com/oneweb-spacex-optimistic-about-cheap-user-terminals/

Offline su27k

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Re: Starlink : Hardware Design / Manufacturing
« Reply #23 on: 03/16/2020 12:53 pm »
There's a reddit thread discussing How does each Starlink satellite handle so much bandwidth? What kind of hardware is needed to process this quantity of information?, user Origin_of_Mind made a reply that I think it's interesting:

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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.

OneWeb's FCC filing is this document: https://licensing.fcc.gov/myibfs/download.do?attachment_key=1134939, not sure if there's an equivalent filing from SpaceX.

Offline gongora

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Re: Starlink : Hardware Design / Manufacturing
« Reply #24 on: 03/16/2020 03:50 pm »
As a reminder: For links to other Starlink discussion threads, launch threads, and FCC filings take a look at the Starlink Index Thread

There are similar documents for the SpaceX filings.  You might need to cross-reference the older and newer filings since SpaceX keeps making changes.  Go to "Attachment Menu" on the filing and then you can look through the relevant documents.

Offline gongora

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Re: Starlink : Hardware Design / Manufacturing
« Reply #25 on: 03/16/2020 04:02 pm »
The SpaceX system does use Ku for the user beams and Ka for the gateways.  That's why we're a little fuzzy on how to refer to the v0.9 satellites, and what their future is.  They lack the Ka beams and have to use the Ku beams for both user and gateway (which doesn't match the FCC license).

Offline su27k

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Re: Starlink : Hardware Design / Manufacturing
« Reply #26 on: 03/16/2020 05:12 pm »
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.

Offline gongora

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Re: Starlink : Hardware Design / Manufacturing
« Reply #27 on: 03/16/2020 05:43 pm »
OneWeb made some simplifying architectural decisions when they designed their satellites.  They stuck to a lot of proven design elements.  If their design had been done a couple years later it may have been much different.  The industry is now moving to digital payloads, and if OneWeb makes it to a second generation constellation they probably will too.  SpaceX was much more aggressive with their design.

Offline Eka

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Re: Starlink : Hardware Design / Manufacturing
« Reply #28 on: 03/17/2020 03:30 am »
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.
As somebody who is familiar with a 10Gb 8ch router that was developed in the late '90s/early 2ks, it can be done. Their programmable logic version was handling 4 ports, and the first test silicon did 8 with ease. There was talk of making a 12 or 16 channel one, but 9/11 hosed them. Now silicon is faster and allows for far more gates.

For low latency, you want to handle that packet now, and send it on as soon as possible. That means a routed system. The plan to use lasers between satellites also means there is a need for routing at the satellite level. Packet routing is simple comparisons and can be done very fast. Often knowable before the whole header is received. Route planning is a different issue than packet routing. When the first packet to a destination site is received, a route plan needs to be generated. I tells which output port to use to get closer to the destination. Subsequent packets can use that route until the geometry of the network changes too much. Then a new route needs to be calculated.
We talk about creating a Star Trek future, but will end up with The Expanse if radical change doesn't happen.

Offline FutureSpaceTourist

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Re: Starlink : Hardware Design / Manufacturing
« Reply #29 on: 03/18/2020 11:56 am »
Quotes below from today’s SpaceX webcast for the Starlink launch:

twitter.com/thesheetztweetz/status/1240258825078353920

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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."

https://twitter.com/thesheetztweetz/status/1240259238141796358

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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."

Offline Roy_H

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Re: Starlink : Hardware Design / Manufacturing
« Reply #30 on: 03/21/2020 04:24 am »
It seems to me that the simplest sunshade would be to use the solar panels. Minimal extra mass and design change. The solar panels shading the rest of the satellite could have heat rejection panels on back side in same orientation as used on ISS which would radiate excess heat away from the satellite.
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Offline RedLineTrain

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Re: Starlink : Hardware Design / Manufacturing
« Reply #31 on: 03/21/2020 08:28 pm »
FYI, the license for the ground terminal shows the antenna diameter as 0.48 meters, or 19 inches.

Offline Bananas_on_Mars

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Re: Starlink : Hardware Design / Manufacturing
« Reply #32 on: 08/14/2020 06:41 pm »
I can’t remember seeing the tension rods on the Starlink stack in such detail before

https://twitter.com/planetlabs/status/1294267537174089729

Offline gongora

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Re: Starlink : Hardware Design / Manufacturing
« Reply #33 on: 08/14/2020 07:13 pm »
I can’t remember seeing the tension rods on the Starlink stack in such detail before

The pic of the BlackSky sats from the last launch also showed a lot of detail.  You can see the SpaceX and Planet adapters well here.

Offline Ronsmytheiii

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Re: Starlink : Hardware Design / Manufacturing
« Reply #34 on: 09/05/2020 09:51 pm »
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?


Offline RedLineTrain

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Re: Starlink : Hardware Design / Manufacturing
« Reply #35 on: 09/05/2020 10:08 pm »
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?

No.  There haven't been any SpaceX building permits for the newly-built adjacent building.  It seems to make sense that they would lease that one to fill out the campus and allow a further ramp of production, but there are no indications of this as yet.

Here's a better picture of the building and a description of it.

https://www.sierraind.com/project-completion-redmond-ridge-113/

We can see the SpaceX building permits supporting the build-out of 22908, 23020, and 23040 NE Adler Crest Drive.
« Last Edit: 09/05/2020 10:30 pm by RedLineTrain »

Offline su27k

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Re: Starlink : Hardware Design / Manufacturing
« Reply #36 on: 09/07/2020 04:33 am »
Tim Farrar is saying on twitter that current Starlink satellite and terminal wouldn't support crosslink, any reason to believe his claims?

https://twitter.com/TMFAssociates/status/1301529567308337152

It seems that he's saying Starlink is the same as OneWeb, basically just acting as a repeater between terminal and gateway, but I thought the general consensus is that that's not the case?

(I know this guy is super shady, just curious if he has any basis to make this claim, since I'm not familiar with the technology details such as TDD)

Offline exilon

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Re: Starlink : Hardware Design / Manufacturing
« Reply #37 on: 09/07/2020 05:59 am »
Why would the consumer terminal care? Signal goes up to a satellite, signal comes down from the satellite.
Currently the signal from a terminal goes from terminal->sat->ground->backbone->ground->sat->terminal

The crosslinks would enable terminal->sat*N->ground->backbone->ground->sat*N->terminal or even a dedicated terminal->sat*N->terminal transmission.
Note that there's no change to the terminal->sat or sat->terminal interface.

The crux of the argument seems to be the satellites cannot host enough compute to handle the routing themselves and Musk is a con-man.

Smells very similar to the end-stage flailing of Twitter Tesla shorts around mid-2019. Dubious/vague technical claim plus character attack, and repeat.

Offline Lar

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Re: Starlink : Hardware Design / Manufacturing
« Reply #38 on: 09/07/2020 06:24 am »
The 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.
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Offline guckyfan

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Re: Starlink : Hardware Design / Manufacturing
« Reply #39 on: 09/07/2020 06:58 am »
The 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.

For once I disagree with you. The sat has to handle thousands of connections and the handover to another satellite. I don't see the sats handling routing. They are busy enough handing data through in point to point operations, not handling the higher protocol levels and route every stream separately. A single end user terminal may have hundreds of separate streams. Routing nodes will remain on the ground.

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