Author Topic: SpaceX - now a satellite manufacturer (Starlink)  (Read 702051 times)

Offline gongora

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2520 on: 02/13/2019 02:47 am »
One reason for deploying lower is that a dead sat will actually deorbit eventually from 600km.  The extra demands on propulsion for raising and then lowering again seems to be one of the reasons SpaceX wants to just use a lower orbit on the initial sats.

Online ThomasGadd

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2521 on: 02/13/2019 03:07 am »
I got why they changed the initial group 24 x 66 at 550 km.  It allows them to deploy quicker and gain flight experience with operational birds also they can be de-orbited quicker from there if needed... lots of advantages.

Online Cheapchips

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2522 on: 02/13/2019 05:50 am »
Musk agreed with this tweet from Carmack:

Quote
I wonder what the trade offs are for piggy backing other instruments on low orbit comm sat constellations. You arenít going to get a Keyhole aperture, but being able to have 24/7 coverage of anywhere seems valuable. @elonmusk

https://twitter.com/ID_AA_Carmack/status/1094725061267865601

I can't recall if SpaceX had discussed this at all.
« Last Edit: 02/13/2019 06:40 am by Cheapchips »

Online docmordrid

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2523 on: 02/13/2019 06:22 am »
Not overtly, but with the USAF testing the MicroSats for aircraft comms hosted DoD payloads seems a short putt.
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Offline gongora

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2524 on: 02/13/2019 01:58 pm »
Musk agreed with this tweet from Carmack:

Quote
I wonder what the trade offs are for piggy backing other instruments on low orbit comm sat constellations. You arenít going to get a Keyhole aperture, but being able to have 24/7 coverage of anywhere seems valuable. @elonmusk

I can't recall if SpaceX had discussed this at all.

Are you familiar with the Blackjack program?  All of the LEO constellation providers will be looking at participating in things like this, whether it's allowing additional payloads on their comsats or giving the customer dedicated satellites with their own payloads that will interact with the constellation.
« Last Edit: 02/13/2019 01:59 pm by gongora »

Offline Tulse

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2525 on: 02/13/2019 02:16 pm »
I would be really surprised if there hadn't be serious discussion of adding basic imaging to Starlink satellites.

That said, what level of gear would one need to get, say, meter per pixel resolution at 600 km?  Or alternatively, what resolution could one reasonably get with gear that could be added on to a basic Starlink satellite without adding excessive weight, complexity, and power requirements?

Offline Ludus

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2526 on: 02/13/2019 03:05 pm »
Whatever level it starts at, it will rapidly get better. There will be 24/7 nearly continuous high res orbital imaging of everywhere. The same will be applied to Mars when the constellation is established there. There is a lot of demand just stimulated by Planet Labs. There are lots of unexpected uses for this sort of constant imaging combined with AI processing.

Online 2megs

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2527 on: 02/14/2019 03:30 am »
Whatever level it starts at, it will rapidly get better.

Unfortunately, optics isn't one of the things that gets better according to Moore's Law. Basic physics put a limit on how much angular detail you can resolve, limited by the wavelength of the light and the diameter of the lens. There's no getting better without getting into a lower orbit (and StarLink phase 2 is about as low as practical) or putting bigger heavier lenses into orbit (which is antithetical to the idea of lots of smaller cheaper satellites).

Offline Asteroza

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2528 on: 02/14/2019 03:40 am »
Repurposing the gear from the intersat lasercomm telescopes would probably put you into 1m GSD territory from the lower tiers in Starlink, just grind the mirror a bit differently. You're not likely to get a larger primary mirror as a secondary hosted payload with a hard mirror, so that probably is the upper limit. Now, using a diffractive optics membrane lens instead, you could get better resolution via a larger lens, potentially 2m or more in diameter, which could get you below 1m GSD. There's the practical issue that sub 50cm imagery is still tightly regulated (previously 1m was the limit for unrestricted commercial), so reaching for that might have unintended consequences.

Offline Ludus

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2529 on: 02/14/2019 04:32 am »
Whatever level it starts at, it will rapidly get better.

Unfortunately, optics isn't one of the things that gets better according to Moore's Law. Basic physics put a limit on how much angular detail you can resolve, limited by the wavelength of the light and the diameter of the lens. There's no getting better without getting into a lower orbit (and StarLink phase 2 is about as low as practical) or putting bigger heavier lenses into orbit (which is antithetical to the idea of lots of smaller cheaper satellites).

Yes, optics is one of the things that gets better according to Mooreís law.
https://forum.nasaspaceflight.com/index.php?topic=39447.20
https://www.aqueti.com
Digital image processing means you arenít restricted to a single lens. You can have much lighter flat devices that gather more light. I also donít think Starlink satellites will stay especially small, I think theyíll get larger even as they get more sophisticated. Starship is capable of launching and maintaining a Constellation of 12000 satellites each of which is thousands of kilos.

A Starlink generation will only be 3-5 years long. Each generation will get better, including imaging.
« Last Edit: 02/14/2019 04:45 am by Ludus »

Offline IainMcClatchie

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2530 on: 02/14/2019 08:32 am »
Optics does not follow Moore's law.  That Aqueti thing is for getting more field of view with more apertures, which isn't even how you'd do it with a space-based telescope.  A 4.5 degree field of view is practical with large diffraction limited optics.

Folks have talked about super-resolution, and also about combining multiple apertures electronically rather than optically to get better resolution.  Nothing works yet.  Diffractive optics works in consumer lenses where the diffraction grating has anomalous dispersion which can be used to cancel the dispersion of other large lens elements.  It's like cheap, lighter weight fluorite.  Really big diffractive optics are still a theoretical construct.

The ITAR limit on aperture was increased from 35 cm to 50 cm in the last couple years.  50 cm from a 550 km orbit gives you 74 cm Rayleigh limit for green light when looking straight down.  1 m GSD for many targets would be practical.

Offline Tulse

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2531 on: 02/14/2019 02:39 pm »
1 m resolution for continuous monitoring would be more than sufficient, I would think, as one can extract a lot more data out of video than multiple stills separated by long time frames (at least for certain applications).

Offline Tuna-Fish

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2532 on: 02/18/2019 10:13 pm »
Isn't the current trend in surveillance based on wide area monitoring, rather than reading license plates from orbit? The idea being, use sensors with low area resolution but with ridiculously wide field of view, like the ARGUS-IS sensor used in MQ-9 Reaper that consists of ~400 cell phone cameras looking through a single lens, simultaneously surveilling an area of 100km^2.

The idea being using really good compression and motion tracking algorithms to not just track, but store all movement in the area surveilled over the time of months. Then when a roadside bomb goes off, they can go find the spot on their feed, and rewind back until they find when it was planted, and then start tracking the people who did that while following them both backwards and forwards in time, finding out both where they came from (and where they got the explosives, etc) and where they went after.

For that kind of duty, something like Starlink satellites with commercial-grade lenses with their ~1 meter resolution is sufficient.

Offline RedLineTrain

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2533 on: 02/19/2019 09:53 pm »
Interesting to see a few satellite positions opened in Hawthorne.  The balance of power seems to still reside in Redmond and there are still a few open positions for ASIC design in Irving.  Note that staffing at Redmond seems static to slightly lower.

And from recent job postings it seems to be clear that the user terminal is being handled out of Hawthorne.  Not entirely clear, but it appears that satellites with defense payloads (Blackjack?) are also being handled out of Hawthorne.

Online jpo234

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2534 on: 02/20/2019 11:02 am »
« Last Edit: 02/20/2019 11:04 am by jpo234 »
You want to be inspired by things. You want to wake up in the morning and think the future is going to be great. That's what being a spacefaring civilization is all about. It's about believing in the future and believing the future will be better than the past. And I can't think of anything more exciting than being out there among the stars.

Offline Lar

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2535 on: 02/20/2019 09:01 pm »
Found on Reddit:

https://twitter.com/seattleix/status/1097994337349029889

Quote
Welcome SpaceX - Starlink (AS14593) at 10G.

SeattleIX = Seattle Internet Exchange
Is the AS number their identifier for interchanges of data with other backbones?  10G doesn't seem like a lot for production but fine for testing?
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Online starsilk

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2536 on: 02/20/2019 09:15 pm »
Found on Reddit:

https://twitter.com/seattleix/status/1097994337349029889

Quote
Welcome SpaceX - Starlink (AS14593) at 10G.

SeattleIX = Seattle Internet Exchange
Is the AS number their identifier for interchanges of data with other backbones?  10G doesn't seem like a lot for production but fine for testing?

yes, it's the system identifier for the BGP protocol, which figures out how to get traffic from 'A' to 'B' via multiple, changing routes. they'll be allocated a block of IP addresses and traffic will find its way to those IP addresses based on this.

Online jpo234

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You want to be inspired by things. You want to wake up in the morning and think the future is going to be great. That's what being a spacefaring civilization is all about. It's about believing in the future and believing the future will be better than the past. And I can't think of anything more exciting than being out there among the stars.

Online jpo234

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You want to be inspired by things. You want to wake up in the morning and think the future is going to be great. That's what being a spacefaring civilization is all about. It's about believing in the future and believing the future will be better than the past. And I can't think of anything more exciting than being out there among the stars.

Offline gongora

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Re: SpaceX - now a satellite manufacturer (Starlink)
« Reply #2539 on: 02/21/2019 10:03 pm »
0276-EX-ST-2019 LV comms
0279-EX-ST-2019 LV recovery

A couple of new STA requests from SLC-40 starting April 26, mission number 1488. Thought it could be for Amos-17 but the ASDS location is northeast (and 600+ km).

That's puzzling.
Could it be for previously unannounced flight such as a full load of Starlink test sats?

You wouldn't do a "full load" of "test sats".  It will also be a while before they know if they have permission to leave their non-test sats operating at the lower orbit, so if they're going to start launching them now I hope the propulsion systems are really capable of getting to the higher orbit and back.

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