Starlink direct to cell (was SpaceX & T-mobile event 25 Aug 2022)

[raptorx2]

FCC seeks additional information on SpaceX's VLEO constellation request.  Including V Band and Direct 2 Cell "potential interference" with Omnispace.

"12. Please provide an interference analysis for operations in the PCS G-Block that addresses possible satellite-to-satellite interference given the side lobe angles at the proposed lower altitudes of 340- 360 km. Please include modeled antenna patterns with this analysis. Please submit the requested information by July 8, 2024."

SAT-LOA-20200526-00055

https://licensing.fcc.gov/myibfs/download.do?attachment_key=28441158

[raptorx2]

In only 10 days after SpaceX filed it's Petition for Reconsideration of the FCC SCS R&O regarding Out of Band Power Flux Density (OOBPFD) requirements that SpaceX stated that it's Direct-to-Cell system could not meet in aggregate, which the newly adopted Rules require

(1) Out of band emission limits.
Notwithstanding the emission limitations of § 25.202(f), the aggregation of all space station downlink emissions outside a licensee’s SCS frequency band(s) of operation shall not exceed a power flux density of -120 dBW/m2 /MHz at 1.5 meters above ground level.

Yet, in the docket even ATT claimed that the "appropriate PFD levels should not exceed a power flux density of only  -107.5 dBW/m2 /MHz at 1.5 meters above ground level

On May 30th, SpaceX filed a "Petition for Reconsideration of the Out of Band emission limit of -120 dBW/m2 /MHz in aggregate, suggesting an increase to -110 dBW/m2 /MHz which SpaceX claimed was a level that SpaceX Direct 2 Cell "could meet" in aggregate.  Which was still 2.5db lower than the level ATT claimed was appropriate.

The FCC's promptness in releasing a Public Notice on this issue is yet another positive indication of the FCC working quickly to get SCS to market, "Likely to embolden FCC Chairwoman Rosenworcel's "legacy" in case of a change of Administration in early 2025.

Out of an abundance of caution.  SpaceX has also filed for a "waiver" of the rule.

I would suspect we will see SpaceX file an STA for the current experimental Direct 2 cell testing methodology for this aggregate -110 dBW/m2 /MHz OOBPFD limits while the Petition for Reconsideration moves forward at the FCC.

[catdlr]

https://twitter.com/SpaceX/status/1803287770192105834

SpaceX
@SpaceX
On orbit, the 13 with Direct to Cell capabilities will connect over laser backhaul to the existing constellation, using an advanced modem on board that acts as a cellphone tower in space
9:44 PM · Jun 18, 2024

·

[RedLineTrain]

https://twitter.com/SpaceX/status/1803287770192105834

SpaceX
@SpaceX
On orbit, the 13 with Direct to Cell capabilities will connect over laser backhaul to the existing constellation, using an advanced modem on board that acts as a cellphone tower in space
9:44 PM · Jun 18, 2024

·

Very interesting to see that the D2C satellites currently don't have even backhaul in RF!

[DanClemmensen]

Very interesting to see that the D2C satellites currently don't have even backhaul in RF!

This makes a lot of sense. These satellites need the largest D2C antennas they can support, so there is no room left for RF network-side links. But D2C bandwidth will be relatively small compared to Starlink terminal users, so the Laser links will not impose too big a load on the rest of the ISL net.

[raptorx2]

Federal Register (Thursday June 20th) publishes SpaceX OOBPFD Petition for Reconsideration.

Opposition to Petition due July 5th, with Comments to Opposition due July 15th.

That is only 9 Federal Business days between SpaceX filing and publication in the Federal Register.

https://www.federalregister.gov/documents/2024/06/20/2024-13407/petition-for-reconsideration-of-action-in-rulemaking-proceeding

 

[raptorx2]

Very interesting to see that the D2C satellites currently don't have even backhaul in RF!

This makes a lot of sense. These satellites need the largest D2C antennas they can support, so there is no room left for RF network-side links. But D2C bandwidth will be relatively small compared to Starlink terminal users, so the Laser links will not impose too big a load on the rest of the ISL net.

Think Plug N' Plazer here. Do they really want the main LISL latency to be impacted by a large number of Direct 2 Cell payloads which only provide minimal additional data loading?  Perhaps, the 7 Standard Starlink payloads that accompany the 13 DTC payloads have some additional capability to connect 2 Plug N' Plazer satellites into the main LISL network.   This would also decrease production costs and launch costs.

[raptorx2]

Not to mention that a "Starlink D2C Inc" which in effect becomes a "data relay" client  of Starlink perhaps provides an opportunity to be "spun-off" as a independent company.  Think IPO.

[raptorx2]

FCC seeks additional information on SpaceX's VLEO constellation request.  Including V Band and Direct 2 Cell "potential interference" with Omnispace.

"12. Please provide an interference analysis for operations in the PCS G-Block that addresses possible satellite-to-satellite interference given the side lobe angles at the proposed lower altitudes of 340- 360 km. Please include modeled antenna patterns with this analysis. Please submit the requested information by July 8, 2024."

SAT-LOA-20200526-00055
https://licensing.fcc.gov/myibfs/download.do?attachment_key=28441158

SpaceX responds to the FCC's questions on VLEO deployments.

https://licensing.fcc.gov/myibfs/download.do?attachment_key=28716539

[DanClemmensen]

Not to mention that a "Starlink D2C Inc" which in effect becomes a "data relay" client  of Starlink perhaps provides an opportunity to be "spun-off" as a independent company.  Think IPO.

Commentators seem to be desperate for SpaceX to spin off one or more subsidiaries and then have them go public. But SpaceX does not need the money, and I strongly suspect that Elon has become very averse to operating in a publicly-traded company. Just because lots of folks would like to buy stock does not mean Elon wants to sell.

[raptorx2]

Not to mention that a "Starlink D2C Inc" which in effect becomes a "data relay" client  of Starlink perhaps provides an opportunity to be "spun-off" as a independent company.  Think IPO.

Commentators seem to be desperate for SpaceX to spin off one or more subsidiaries and then have them go public. But SpaceX does not need the money, and I strongly suspect that Elon has become very averse to operating in a publicly-traded company. Just because lots of folks would like to buy stock does not mean Elon wants to sell.

A spin off provides several positives:
First, flush with a large pile of IPO cash.  DtC Spinco would then purchase satellites, and launch services from SpaceX at "market rates".  Not to mention ongoing Data Relay Services.  This would effectively transfer much of IPO cash from DtC SpinCo to SpaceX. (See similar setup with Globalstar founded by Loral Space and Qualcomm.  The IPO provided a "feeding trough" of Cash for the "Partners" for procurement of satellites and Ground/User Terminal development.)
Direct to Cell is, in my opinion, a ZERO Billion dollar industry.  Better to put the "risk" outside of SpaceX. An IPO also provides spin-off shares to SpaceX shareholders/employee shareholders who then have a public outlet to monetize. The topology of the Starlink DtC satellites which are not "intertwined" with the Broadband Satellites in forming the main LISL topology specifically provides the ease in which to divorce the two constellations. Starlink / DtC SpinCo.  Providing a venue of providing Tesla shareholders the ability to participate in DtC Spinco IPO would also bolster Tesla Share Price.

[raptorx2]

Interesting DtC orbital analysis

https://x.com/FREESPEECH1017/status/1803973762137886939

[r1279]

Interesting DtC orbital analysis

https://x.com/FREESPEECH1017/status/1803973762137886939

Have you done the same for past DTC launches such as 8-1, 8-2 and 8-7 where the Ku and DTC satellites are now maintaining at significantly different altitudes to see how your/this interpretation holds up?

[raptorx2]

I believe the first 2 lGroup 8 aunches of 7 each had integrated backhaul from the photos supplied. Those are at 365km.  I consider them test satellites.  Like the original V2.0minis. 6-1, 6-2.  I suspect the the LISLs on board may be lighter/lower cost than the 100Gbps units used on traditional Group 5/6/7 LISLs. 

DTC LISL backhaul will be a fraction of the brosdband backhaul. 

[raptorx2]

FCC approves Nationwide testing of Direct to Cell in Japan with KDDI.

https://apps.fcc.gov/els/GetAtt.html?id=352743&x=.

[gongora]

I believe the first 2 lGroup 8 aunches of 7 each had integrated backhaul from the photos supplied. Those are at 365km.  I consider them test satellites.  Like the original V2.0minis. 6-1, 6-2.  I suspect the the LISLs on board may be lighter/lower cost than the 100Gbps units used on traditional Group 5/6/7 LISLs. 

DTC LISL backhaul will be a fraction of the brosdband backhaul.

I don't know what you mean by photos showing "integrated backhaul" on the earlier DTC sats.  I also don't see any reason SpaceX would use different OISL on the DTC sats.

[gongora]

SpaceX applied for FCC permits to allow DTC testing in New Zealand and Australia.
1209-EX-ST-2024
1210-EX-ST-2024

[raptorx2]

SpaceX applied for FCC permits to allow DTC testing in New Zealand and Australia.
1209-EX-ST-2024
1210-EX-ST-2024

Thanks,
Must have be added late in the day yesterday.

[raptorx2]

I believe the first 2 lGroup 8 aunches of 7 each had integrated backhaul from the photos supplied. Those are at 365km.  I consider them test satellites.  Like the original V2.0minis. 6-1, 6-2.  I suspect the the LISLs on board may be lighter/lower cost than the 100Gbps units used on traditional Group 5/6/7 LISLs. 

DTC LISL backhaul will be a fraction of the brosdband backhaul.

I don't know what you mean by photos showing "integrated backhaul" on the earlier DTC sats.  I also don't see any reason SpaceX would use different OISL on the DTC sats.

I am not saying that they ARE using a lower speed/cheaper/lighter OISL system on the DtC only Satellites.  But, the maximum data backhaul rate for DtC is going to be a fraction of a V2.0Mini for Broadband.  10Mhz FDD = 65Mbs (up/down) per beam, with 8 beams per satellite. 

I am saying it is in SpaceX's "genes" to create the greatest efficiencies for the required objectives.  No matter how "obtuse" it may seem to the passerby.   

I submit for your approval.   The F9 Second Stage.  "Stubby Nozzle"

[gongora]

If you use the same OISL for all the sats, the DTC could sit in-plane with the normal Starlinks and be part of the ring for that plane, otherwise you need to dedicate OISL on the normal sats to talk to the DTC sats.  (I have no idea which way they'll actually structure it.)  I could see doing slightly different versions of OISL for in-plane and out-of-plane if having a smaller pointing range would save money/mass.

What are you trying to show with the picture?