Author Topic: Starlink : New FCC and ITU Filings  (Read 284018 times)

Offline schaban

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Re: Starlink : New FCC and ITU Filings
« Reply #40 on: 06/28/2019 03:54 pm »
edit: FCC just posted the exhibits link for 0515 but I don't have time now to look through it if someone else wants to cut and paste the purpose.

Quote
SpaceX anticipates that the Ground-to-Air testing will require four to six weeks to complete.
Example test sequence for new antenna:
1. Wait for satellite to rise to 40 degrees elevation over test site
2. Initiate broadband test from ground
3. Perform broadband test with earth stations (either on ground or airborne)
4. Satellites set below 40 degrees elevation as viewed from test site
5. Satellite disables Ku-band broadband system

Offline gongora

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Re: Starlink : New FCC and ITU Filings
« Reply #41 on: 07/21/2019 01:05 am »
An excerpt from SpaceX comments on another proposed constellation:
Quote
Specifically, Boeing points to the fact that SpaceX’s NGSO authorization to operate in the V-band included 4,425 satellites operating
at LEO altitudes and another 7,518 satellites operating in very-low-Earth orbit (“VLEO”). Boeing asserts that this was actually two NGSO systems rather than one.
 Yet SpaceX’s V-band constellation was proposed as a single integrated NGSO system, and was authorized as such, including a single performance bond with milestones that apply to “the maximum number of proposed space stations” in both LEO and VLEO orbits.
« Last Edit: 07/21/2019 03:23 am by gongora »

Offline gongora

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Re: Starlink : New FCC and ITU Filings
« Reply #42 on: 07/21/2019 03:24 am »
Document added to my post above.  I mostly found it interesting as a clarification that SpaceX does have two separate constellations of payloads that will share the ~4000 LEO satellites (assuming the V-Band constellation actually gets built and those frequencies are added to the LEO satellites).
« Last Edit: 07/21/2019 03:27 am by gongora »

Offline dondar

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Re: Starlink : New FCC and ITU Filings
« Reply #43 on: 07/21/2019 07:18 am »
Document added to my post above.  I mostly found it interesting as a clarification that SpaceX does have two separate constellations of payloads that will share the ~4000 LEO satellites (assuming the V-Band constellation actually gets built and those frequencies are added to the LEO satellites).
VLEO constellation does have separated deployment deadlines. More of it the deadline is not final because V band is not regulated. When it will happen SpaceX will send another amendment which will be accepted. It is more 2022 than 2020 and the deployment will have to be counted from that time.

That is why I pointed that counting 7k satellites in the current SpaceX deployment numbers is misleading. And that is why I pointed that the absence of the amendments and SpaceX "objections" on VLEO constellation means that the SpaceX themselves have no idea what to do with all this. It is postponed.

Offline gongora

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Re: Starlink : New FCC and ITU Filings
« Reply #44 on: 07/21/2019 02:37 pm »
VLEO constellation does have separated deployment deadlines. More of it the deadline is not final because V band is not regulated. When it will happen SpaceX will send another amendment which will be accepted. It is more 2022 than 2020 and the deployment will have to be counted from that time.

The V-band constellation was already approved.  The deployment clock has already started.

Offline Lar

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Re: Starlink : New FCC and ITU Filings
« Reply #45 on: 07/22/2019 01:26 am »
That is why I pointed that counting 7k satellites in the current SpaceX deployment numbers is misleading. And that is why I pointed that the absence of the amendments and SpaceX "objections" on VLEO constellation means that the SpaceX themselves have no idea what to do with all this. It is postponed.
What do you mean by "no idea what to do" ???
"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
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Offline gongora

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Re: Starlink : New FCC and ITU Filings
« Reply #46 on: 07/26/2019 10:32 pm »
Quote
REQUEST FOR EXTENSION OF SPECIAL TEMPORARY AUTHORITY

On May 9, 2019, the Commission granted SpaceX Services, Inc. (“SpaceX Services”) Special Temporary Authority (“STA”) to operate its gateway earth stations for up to 60 days to communicate with the first tranche of non-geostationary orbit (“NGSO”) satellites launched by its sister company, Space Exploration Holdings, LLC (“SpaceX”), on May 24, 2019.  SpaceX Services respectfully requests that the Commission extend that STA for an additional 60 days for the reasons discussed below.

SpaceX Services currently has applications pending for Ku-band gateway earth stations in six locations: North Bend, WA; Conrad, MT; Merrillan, WI; Greenville, PA; Redmond, WA; and Hawthorne, CA. It has operated these earth stations pursuant to the STA for nearly two months, and has received no complaints from any other authorized spectrum user.

The operation of these earth stations has enabled SpaceX Services to communicate with the SpaceX NGSO satellites and conduct in-orbit testing during the orbit-raising phase. While much of that phase is now complete, there are still some satellites that have yet to reach their authorized altitude of 550 km. In addition, there are two spacecraft that are being intentionally deorbited in order to assess performance during this phase of the mission. Extending the STA would allow SpaceX to continue to monitor the operational status of its satellites to ensure proper functioning and determine operational capabilities. Accordingly, extension of the STA will continue serve the public interest by enhancing space safety and promoting the health and safety of SpaceX’s NGSO constellation.

Offline gongora

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Re: Starlink : New FCC and ITU Filings
« Reply #47 on: 08/16/2019 09:21 pm »
SpaceX filed another extension request for their Ku-band earth stations since they are still operating under STA.

SpaceX also filed their first couple applications for Ka-band gateways (it says they will have at least five).  They will have eight 1.5m antennas at each site.  The first two filed are for Conrad, Montana (SES-LIC-INTR2019-03001) and Loring, Maine (SES-LIC-INTR2019-03002).  The Coordination Report file has info on the antennas.
« Last Edit: 08/16/2019 09:25 pm by gongora »

Offline gongora

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Re: Starlink : New FCC and ITU Filings
« Reply #48 on: 08/28/2019 02:48 am »
Application for Ka-band gateway in Redmond, Washington.
SES-LIC-INTR2019-03100

Offline vaporcobra

Re: Starlink : New FCC and ITU Filings
« Reply #49 on: 08/30/2019 11:42 pm »
Additionally, a request to modify the orbital spacing of SpaceX's 550 km tranche in order to expand coverage of the US without adding satellites or changing altitude/inclination. Just starting to read.

https://fcc.report/IBFS/SAT-MOD-20190830-00087

Offline snotis

Re: Starlink : New FCC and ITU Filings
« Reply #50 on: 08/30/2019 11:57 pm »
Additionally, a request to modify the orbital spacing of SpaceX's 550 km tranche in order to expand coverage of the US without adding satellites or changing altitude/inclination. Just starting to read.

https://fcc.report/IBFS/SAT-MOD-20190830-00087

Some interesting bits from the 'Technical Attachment' at https://fcc.report/IBFS/SAT-MOD-20190830-00087/1877671

Quote
Through  extensive  study  of  orbital  formations  and  spacecraft performance, SpaceX has identified a system architecture that will enable deployment in a way that will provide robust broadband service to more Americans more quickly.  Based on the success of its revolutionary deployment process, SpaceX has confirmed its ability to populate three planes with a single launch.  By then reorganizing the same satellites at the same altitude, SpaceX  can  place  coverage  and  capacity  more  evenly  and  rapidly  across  more  of  the  U.S.,  accelerating broadband service to middle and southern states, as well as to Hawaii, Puerto Rico, and the U.S. Virgin Islands.

Quote
With  this  application,  SpaceX  seeks  to  modify  its  license  to  implement  that  system  architecture.  It involves only an adjustment of the orbital spacing of SpaceX’s satellites operating at the 550 km altitude, increasing the number of orbital planes while commensurately decreasing the number of satellites in each plane.  As summarized in Table 1, it would simply increase the number of orbital planes from 24 to 72, with a corresponding decrease in the number of satellites in each plane from 66 to 22.  This adjustment would not change the total number of satellites, operational altitude, or inclination of the orbital planes.  Nor would the modification change the radio frequency characteristics of the individual satellites or the beneficial orbital debris mitigation characteristics of their operation at this lower altitude.

Offline gongora

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Re: Starlink : New FCC and ITU Filings
« Reply #51 on: 08/31/2019 12:23 am »
Engaging with astronomical community to get measurements and ideas on lowering albedo of the satellites.

350km injection orbit.

Deorbit by lowering perigee to 300km, then maintain enough fuel for conjuction avoidance while it passively deorbits.

Satellites after the first deployment still planned to be fully demisable.


Re: Starlink : New FCC and ITU Filings
« Reply #52 on: 08/31/2019 01:54 am »
At 550 km the minimum sats. is 11 for minimum visibility with no resilience.  Doubling that to 22 gives full redundancy.

Offline gongora

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Re: Starlink : New FCC and ITU Filings
« Reply #53 on: 08/31/2019 02:00 am »
At 550 km the minimum sats. is 11 for minimum visibility with no resilience.  Doubling that to 22 gives full redundancy.

Is that for 20 degree minimum elevation?

Re: Starlink : New FCC and ITU Filings
« Reply #54 on: 08/31/2019 02:09 am »
At 550 km the minimum sats. is 11 for minimum visibility with no resilience.  Doubling that to 22 gives full redundancy.

Is that for 20 degree minimum elevation?

I don't remember it's been too long since I calculated it...  it should be in my past posts or I could do it again
I had a parentheses in the wrong place before...

25 degrees above horizon is 3 sats.
 360.0 /((90-25)*2) = 2.7

40 degrees above horizon is 4 sats.
 360.0 /((90-40)*2 = 3.6
« Last Edit: 09/03/2019 02:35 pm by ThomasGadd »

Offline Robotbeat

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Re: Starlink : New FCC and ITU Filings
« Reply #55 on: 08/31/2019 02:28 am »
Engaging with astronomical community to get measurements and ideas on lowering albedo of the satellites.

350km injection orbit.

Deorbit by lowering perigee to 300km, then maintain enough fuel for conjuction avoidance while it passively deorbits.

Satellites after the first deployment still planned to be fully demisable.
350km is very good, and a good change from their first 440km launch. ISS is at 400-420km, so that means dead-on-arrival birds never cross ISS.

Glad SpaceX is being responsive here.
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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

Re: Starlink : New FCC and ITU Filings
« Reply #56 on: 09/01/2019 04:07 pm »
I'm trying to wrap my head around the physics of.

"SpaceX still intends to perform an active disposal of all satellites at the end of their life, which the satellites first drop to a perigee of approximately 300 km while maintaining an apogee at approximately 550 km."

Is it cheap or faster to do this verses both to 300 km? 

Offline gongora

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Re: Starlink : New FCC and ITU Filings
« Reply #57 on: 09/01/2019 04:10 pm »
Is it cheap or faster to do this verses both to 300 km?

Only dropping the perigee is slower but uses less fuel.  If they have more fuel left they can drop perigee even lower.

Offline speedevil

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Re: Starlink : New FCC and ITU Filings
« Reply #58 on: 09/01/2019 04:22 pm »
Is it cheap or faster to do this verses both to 300 km?

Only dropping the perigee is slower but uses less fuel.  If they have more fuel left they can drop perigee even lower.

If I was being asked to do predictable entry, I would want an entry when at all times up until the last orbits you have a long period when you can point the solar panels optimally to get sun, and sort out your orientation so the next high drag pass is as predictable as possible.

Even thrusting to actively raise apogee during these passes to ensure the control perhaps.

As to propellant - it's 40m/s difference between 150*550 and 300km*550, so the propellant needed for this at 1600s is under a kilo naively.


Offline meberbs

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Re: Starlink : New FCC and ITU Filings
« Reply #59 on: 09/01/2019 04:39 pm »
Is it cheap or faster to do this verses both to 300 km?

Only dropping the perigee is slower but uses less fuel.  If they have more fuel left they can drop perigee even lower.
If they have more fuel, rather than drop the apogee as well, it would be faster to drop the perigee more. Air density is basically exponential so drag goes up faster by just lowering the perigee. If they lower the perigee to 200 km, it would decay very quickly. Before they could lower it to 100 km, it would simply already have burned up.

I may have seen it in some documentation somewhere, or maybe I am misremembering, but SpaceX may save a bit of propellant to maintain enough control to dodge anything it passes on the way down

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