Author Topic: SpaceX - now a satellite manufacturer (Starlink)  (Read 719125 times)

Offline WormPicker959

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2600 on: 03/22/2019 04:03 am »
Been waiting for this one...

Quote
Due to SpaceX’s decision to minimize risk by using the low injection altitude of 350 km, in the unlikely event any satellites after the initial launch experience immediate failure upon deployment, they would decay to the point of demise very quickly – as little as two weeks to at most eight months depending on the solar cycle.
...
As discussed in its application, SpaceX plans to deploy two versions of its initial satellites with configurations that include a slightly different set of components. The first version, comprising fewer than 75 satellites, will include an iron thruster and steel reaction wheels on each satellite. As a result of its continuing efforts to attain full demisability, SpaceX now expects to replace the thruster and reaction wheel components in subsequent satellites to use components that will demise fully in the atmosphere. SpaceX no longer intends to deploy any satellites that include the silicon carbide component originally contemplated.

Changing the construction of the inter-satellite laser components?  It's hard to imagine them getting rid of interconnects altogether.

I'm looking at this again, and the comment about the change to full demisability is encouraging. They say they've researched full demisability, and can achieve it. However, they also say their first (fewer than) 75 satellites will contain ion thruster and reaction wheel components, which will remain after reentry and pose a (very small) risk to humans.

The thing that's encouraging about this is that it means that ~75 satellites have already been manufactured, and are planning to be launched. (Well, they say fewer than 75, but I'm not sure why they would pick 75 if it's not somewhere close?) This is interesting, as we know that they are planning an upcoming starlink launch, but we don't know how many sats they plan to deploy in one F9 launch. I think estimates I've seen are around 20-30, so this could mean up to three flights in the relatively near future.

Further, it means that they've already moved on to a second (third, counting the tintins?) version and that they are confident about the design. What kind of thruster and stabilization can be used that is fully demisable? They also say they will still use Hall thrusters, so are they building them without iron cores? Are magnetorquers even feasible on starlink-sized sats? What other non-reaction wheel based stabilization techniques are there?

Online gongora

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2601 on: 03/22/2019 10:19 am »
The thing that's encouraging about this is that it means that ~75 satellites have already been manufactured...

or are in the process of being manufactured.

Offline FutureSpaceTourist

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2602 on: 03/22/2019 10:45 am »
Quote
SpaceX’s Starlink satellite lawyers refute latest “flawed” OneWeb critique
By Eric Ralph
Posted on March 22, 2019

After years of relentless legal badgering from internet satellite constellation competitor OneWeb, SpaceX’s regulatory and legal affairs team appears to have begun to (in a professional manner) lose patience with the constant barrage.

On February 21st, SpaceX published a withering refutation of OneWeb’s latest criticism that offered a range of no-holds-barred counterarguments, painting the competitor – or at least its legal affairs department – as an entity keen on trying to undermine Starlink with FCC-directed critiques based on flawed reasoning, false assumptions, misinterpretations, and more. Alongside a number of memorable one-liners and retorts, legal counselors William Wiltshire and Paul Caritj and SpaceX executives Patricia Cooper and David Goldman openly “wonder whether OneWeb would be satisfied with SpaceX operating at any altitude whatsoever.”

https://www.teslarati.com/spacex-starlink-lawyers-oneweb-critique/

Offline speedevil

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2603 on: 03/22/2019 12:17 pm »
The thing that's encouraging about this is that it means that ~75 satellites have already been manufactured...

or are in the process of being manufactured.
Or to turn the pessimism up to 11, 75 of some set of parts have been ordered.

They may be confident about being able to do fully demisable components, but looking to refine the production process so doing the first few as only mostly demisable speeds things up or makes them cheaper.

The fully manufactured interpretation would be great - launch isn't that far away.

Offline Rondaz

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2604 on: 03/22/2019 01:45 pm »
SpaceX Claims To Have Redesigned Its Starlink Satellites To Eliminate Casualty Risks

A revised design means dead satellites will burn up completely in the atmosphere

By Mark Harris 21 Mar 2019 | 19:30 GMT

https://spectrum.ieee.org/tech-talk/aerospace/satellites/spacex-claims-to-have-redesigned-its-starlink-satellites-to-eliminate-casualty-risks

Offline Spudley

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2605 on: 03/22/2019 10:06 pm »
SpaceX Claims To Have Redesigned Its Starlink Satellites To Eliminate Casualty Risks

A revised design means dead satellites will burn up completely in the atmosphere

By Mark Harris 21 Mar 2019 | 19:30 GMT

https://spectrum.ieee.org/tech-talk/aerospace/satellites/spacex-claims-to-have-redesigned-its-starlink-satellites-to-eliminate-casualty-risks

I totally mis-read that as "eliminate causality risks", and briefly had a mental image of Elon Musk launching time-travelling satellites.

Offline WormPicker959

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2606 on: 03/22/2019 10:38 pm »
The thing that's encouraging about this is that it means that ~75 satellites have already been manufactured...

or are in the process of being manufactured.
Or to turn the pessimism up to 11, 75 of some set of parts have been ordered.

They may be confident about being able to do fully demisable components, but looking to refine the production process so doing the first few as only mostly demisable speeds things up or makes them cheaper.

The fully manufactured interpretation would be great - launch isn't that far away.

I think this is all warranted. I sorta jumped the gun with "already been manufactured" - it's more likely that there are tens of satellites at some stage of the production process. Since their first F9 launch is speculated to be mid-May, this makes sense. I think the speculation is between 20 and 30 sats per F9 launch, so this fits.

I guess I got a bit excited by the way it's being talked about in the letter, and because we get so few details about the sats out of spacex.

Offline Robotbeat

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2607 on: 03/22/2019 10:53 pm »
If SpaceX was super early in the design/manufacturing process, tho, they could’ve gone fully demisable from the start. So I agree it’s a (small) confirmation they’ve been making progress.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline speedevil

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2608 on: 03/22/2019 11:02 pm »
If SpaceX was super early in the design/manufacturing process, tho, they could’ve gone fully demisable from the start. So I agree it’s a (small) confirmation they’ve been making progress.

Specifying something doesn't mean you know how to build it fast, reliably and cheap.

Offline Rocket Rancher

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2609 on: 03/23/2019 12:37 pm »
I will admit up front, I have not followed every posting for this topic, so be gentle if the question is about something previously discussed here ;-)

Is the Starlink spacecraft bus designed only for one mission? Can the bus be easily used/adapted for other payloads?
"In God We Trust ... All Others Bring Data"

Offline JBF

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2610 on: 03/23/2019 09:54 pm »
I will admit up front, I have not followed every posting for this topic, so be gentle if the question is about something previously discussed here ;-)

Is the Starlink spacecraft bus designed only for one mission? Can the bus be easily used/adapted for other payloads?
They have not talked about building anything but starlink.  Since they will be attempting to get the build cost as low as possible the bus is probably highly specific and won't lend itself easily to other payloads.
"In principle, rocket engines are simple, but that’s the last place rocket engines are ever simple." Jeff Bezos

Offline Robotbeat

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2611 on: 03/23/2019 10:37 pm »
If SpaceX was super early in the design/manufacturing process, tho, they could’ve gone fully demisable from the start. So I agree it’s a (small) confirmation they’ve been making progress.

Specifying something doesn't mean you know how to build it fast, reliably and cheap.
Of course, but the fact they’re *skipping* it for the first 75 birds means those 75 birds are significantly far along already. What “significant” means, we may find out in a couple months or so.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Rocket Rancher

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2612 on: 03/23/2019 11:37 pm »
Thanks Robotbeat and JBF. I'm just wondering who will try to commoditize satellite buses for the small sat market? lots of smaller countries and government agencies would probably love to buy an inexpensive, standard bus that meets the their basic requirement and then just concentrate on designing and building their own payloads. Of course price will be the key.
"In God We Trust ... All Others Bring Data"

Offline joek

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2613 on: 03/24/2019 12:36 am »
Thanks Robotbeat and JBF. I'm just wondering who will try to commoditize satellite buses for the small sat market? lots of smaller countries and government agencies would probably love to buy an inexpensive, standard bus that meets the their basic requirement and then just concentrate on designing and building their own payloads. Of course price will be the key.

Or instead of commoditizing satellite buses and manufacturing, Starlink commoditizes resource availability on their "orbital platforms".  Why build your own satellite if SpaceX is willing to rent-lease-sell volume-mass-power-whatever on their Starlink platforms?  We are already seeing similar with, e.g., Iridium.  Won't be for everyone--especially those who want much greater control, autonomy and who can't wait for the next Starlink replenishment cycle--but may work for many.

Online gongora

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2614 on: 04/04/2019 07:11 pm »
Over on r/SpaceX there is a post by u/lgats with some details of new earth station filings for the Starlink constellation.  They did a more thorough job than I feel like doing at the moment, so you might just want to check out the details over on their site.
https://old.reddit.com/r/spacex/comments/b9g8b1/spacex_files_for_6_base_stations_for_starlink/

Offline Robotbeat

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2615 on: 04/05/2019 02:32 am »
This is the antenna for ground stations:
https://www.cobham.com/communications-and-connectivity/satcom/satellite-communication-at-sea/ku-band-maritime-vsat/sea-tel-4009-vsat/sea-tel-4009-vsat-mk3-data-sheet/docview/

Found a similar model antenna used online for about $9000.
https://www.ebay.com/i/292885057660?chn=ps

...so they could service the marine market (and rural mobile backhaul) even if they're not finished with the pizza boxes.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Online gongora

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2616 on: 04/05/2019 03:00 am »
I don't understand these earth station filings.  They only list one antenna per site.  With a steerable antenna following satellites in a LEO constellation wouldn't you have multiple antennas?  (O3B uses three at their gateways, I think it's two live and one backup).  I guess these filings are just for early testing of limited functionality, and the sites will get more antennas later?

Offline Robotbeat

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2617 on: 04/05/2019 03:04 am »
I don't understand these earth station filings.  They only list one antenna per site.  With a steerable antenna following satellites in a LEO constellation wouldn't you have multiple antennas?  (O3B uses three at their gateways, I think it's two live and one backup).  I guess these filings are just for early testing of limited functionality, and the sites will get more antennas later?
They could just use multiple sites to achieve the same result as one site with multiple antennae.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline catdlr

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2618 on: 04/06/2019 02:15 am »
Starlink First 72 Satellites


Mark Handley
Published on Apr 5, 2019

This is a quick simulation to examine what coverage might be like with just the first 72 Starlink satellites deployed.  SpaceX has stated the first 75 satellites will have a different configuration, without laser links.  Assuming they're evenly spread across the 24 orbital planes, reserving 3 for spares, and allowing communication up to 25 degrees from the horizon gives coverage like this.  Ground stations shown are SpaceX's chosen first locations, as of April 2019.  Note, my speculation, based on SpaceX FCC filings, not necessarily what they'll actually build.

https://www.youtube.com/watch?v=5EwVdD1LSYA?t=001

Tony De La Rosa

Offline catdlr

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2619 on: 04/06/2019 03:19 am »
Starlink Early Deployment


Mark Handley
Published on Apr 5, 2019

This is a simulation of Starlink with 264 satellites deployed.  This is close to the minimum required to provide 100% coverage in the US.  Parameters are mainly taken from SpaceX FCC filings, but I have extrapolated some parameters.

https://www.youtube.com/watch?v=J6HYiYPlSHE?t=001

Tony De La Rosa

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