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A classified network of SpaceX satellites is emitting a mysterious signal

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Re: A classified network of SpaceX satellites is emitting a mysterious signal

#71

Post by ACCount37 »

wongarsu wrote: post #42
Zigurd wrote: post #39

Earlier quoted context omitted.

2/3 of Falcon 9 launches are for Starlink. No outside revenue. SpaceX continues to require new investment rounds. So the whole "driving costs down" thing might only work until investors expect some actual free cash flow. There have been 11 test launches of starship. You might've missed the last one because it didn't do anything new, except shedding parts and exploding less. There's a pretty good chance that program w…

The last Starship launch was indeed unspectacular because it didn't try pushing the envelope particularly hard. The previous launches were much more precarious, with many fire balls. But I'm a strong believer in iterative development. It's bad PR when everyone can see every failed prototype, but the "design it once, simulate, and make sure the first prototype flies without issues" boxes you in to conservative design…

They did push Starship hard enough on reentry that, reportedly, it ended up with multiple holes burned through the metal hull and into the tanks.

It survived that - did that entire "simulated landing" burn and all.

Re: A classified network of SpaceX satellites is emitting a mysterious signal

#72

Post by kragen »

xyzzyz wrote: post #55
kragen wrote: post #47

Earlier quoted context omitted.

This is not correct. Low-data-rate satellite communication is generally received on the satellite with omnidirectional antennas, because if you try to do it with directional dishes, any problem with your satellite's attitude control system or position estimation leaves you with a dead satellite, because the directional dish on the satellite is pointed somewhere you don't have a transmitting antenna. Attitude control…

This is not the case with Starlink (and presumably Starlink) satellites. The ground stations use directional phased arrays. They can do it, because they keep good track of where each satellite is at any given moment, and do trajectory adjustments as needed.

Yes, groundstations are virtually always highly directional, except for, like, radio hams sometimes. (Even hams usually use yagis.) Possibly you didn't notice this, but I'm talking about the antennas on the satellites, which are the ones that could suffer interference (since they're the ones receiving the uplink frequencies we're discussing), not the groundstation antennas.

You always have to keep track of where each satellite is at any given moment.

What do you mean by "Starlink (and presumably Starlink)"?

Re: A classified network of SpaceX satellites is emitting a mysterious signal

#73

Post by jdonaldson »

robotresearcher wrote: post #58
Zigurd wrote: post #26

Earlier quoted context omitted.

Places only Starllink can reach are an insufficient and shrinking TAM. The only places a terrestrial wireless provider doesn't want to serve are places that can't afford FWA even though it costs less.

Also where terrestrial access is denied by the local government or infra has been disabled or destroyed. I hope Starlink can maintain enough regular non-crisis subscribers to subsidize this incredibly helpful use case. Perhaps governments could/do pay a retainer to keep this option alive.

I'm quite sure that's what's already going on. LEO is big and empty and pretty boring, but it's also resilient to increasing trends of natural disaster, war, and civil unrest. Having a foothold there matters more and more every day.

Re: A classified network of SpaceX satellites is emitting a mysterious signal

#74

Post by stinkbeetle »

bob1029 wrote: post #59

The mass of the starlink satellites has doubled twice since V1. It is not hard to assume that there is a significant DoD rideshare payload involved on the existing commercial satellites. Having a sensor platform on every single one would be incredible. The satellites that have been officially branded as Starshield (~183 we know of) could be part of cover or a more "kinetic" mission profile. If I was in charge at the…

If you were in charge at the Pentagon, would you have the authority to prohibit civilian access to space on that basis?

Re: A classified network of SpaceX satellites is emitting a mysterious signal

#75

Post by cameldrv »

ACCount37 wrote: post #4

This reeks of SAR (Synthetic Aperture Radar), and we know Starshield sats carry custom sensor payloads that normal Starlinks don't have.

Yeah and the E-7 was recently cancelled. This is what Hegseth said to Congress a few months ago: “The answer is yes. I would. I would file this entire discussion under difficult choices that we have to make. But you know, the E-7, in particular, is sort of late, more expensive and ‘gold plated,’ and so filling the gap, and then shifting to space-based ISR [intelligence, surveillance, and reconnaissance] is a portion of how we think we can do it best, considering all the challenges"

I wonder if Starshield is the platform that is supposed to replace the E-3.

Re: A classified network of SpaceX satellites is emitting a mysterious signal

#76

Post by krisoft »

brookst wrote: post #66
bob1029 wrote: post #59

The mass of the starlink satellites has doubled twice since V1. It is not hard to assume that there is a significant DoD rideshare payload involved on the existing commercial satellites. Having a sensor platform on every single one would be incredible. The satellites that have been officially branded as Starshield (~183 we know of) could be part of cover or a more "kinetic" mission profile. If I was in charge at the…

It's an interesting theory, but I'm not sure it works. Do you design in these sensors and build in the normal starlink factory, where most people don't have security clearances? Or do you make thousands of people get security clearances, making it pretty obvious? And as soon as any data from a specific sensor leaks, adversaries would likely be able to pinpoint what satellite produced it. And then the contractual term…

> where most people don't have security clearances

Are we sure about that? Because i see plenty of clearance required job listings to their redmond facility.

> And as soon as any data from a specific sensor leaks, adversaries would likely be able to pinpoint what satellite produced it.

Yeah. Thats why usually data from any satelite would be very closely held. Even with old satelites it was a big deal when the president just posted an image publicly.

But i don’t understand your argument. Even if it leaks that wouldn’t make the sensor network worthless. Like this argument is true for any spy satelite. If the data from any sensor leaks it is bad. Not a reason to not make the satelite.

Re: A classified network of SpaceX satellites is emitting a mysterious signal

#77

Post by [deleted] »

m4rtink wrote: post #63
next_xibalba wrote: post #27

Earlier quoted context omitted.

Is there a viable alternative? SpaceX is the only launch provider and satellite operator that is progressing at a rapid pace and driving costs down.

Chinese companies seem to be in process of cloning Falcon 9 and even Starlink (Thousand Sails and other constellations). In the west the Rocketlab Neutron partial RLV and planned Stokes Space full RLV stand out. And maybe in a few decades even Arianespace will end up with a Falcon 9 class vehicle! ;-)

[deleted]

Re: A classified network of SpaceX satellites is emitting a mysterious signal

#78

Post by Jtsummers »

kragen wrote: post #72
xyzzyz wrote: post #55

Earlier quoted context omitted.

This is not the case with Starlink (and presumably Starlink) satellites. The ground stations use directional phased arrays. They can do it, because they keep good track of where each satellite is at any given moment, and do trajectory adjustments as needed.

Yes, groundstations are virtually always highly directional, except for, like, radio hams sometimes. (Even hams usually use yagis.) Possibly you didn't notice this, but I'm talking about the antennas on the satellites, which are the ones that could suffer interference (since they're the ones receiving the uplink frequencies we're discussing), not the groundstation antennas. You always have to keep track of where each…

To add to this, we know what objects interfere with our satellite contacts. We keep their orbital positions (as best as possible) in mind when scheduling satellite operations to avoid communication failures (partial or total) caused by their interference.

This is often learned after the fact. A contact will fail or go badly and then you can examine what was around it at the time. Over a series of failures the offending satellite will be identified.

Re: A classified network of SpaceX satellites is emitting a mysterious signal

#79

Post by stinkbeetle »

anonymousiam wrote: post #50

The S-band uplinks are not typically used during operations. They're mostly used during transfer orbit operations and initial testing, and in emergencies when something goes wrong with the normal comms (safe mode). The S-band antennas on the satellite are typically omnidirectional, so they'll hear anything strong enough to overcome the noise floor. Those comms can be encrypted or in the clear, depending upon the situ…

> I'm not involved in this stuff anymore (now retired), but it's possible that the Starshield constellation supports transmitting on S-band (or L-Band) as a means to relay SGLS communications to satellites that are out-of-view. Having this capability would greatly benefit the workflow of transfer orbit operations and initial testing, by eliminating the constraint that the satellite must be in-view to communicate with it. It would also benefit anomaly resolution by allowing instant access to a malfunctioning spacecraft.

That's interesting, thank you for the great comment. Would that kind of usage then not be counter to the standards, as suggested in the article?

Re: A classified network of SpaceX satellites is emitting a mysterious signal

#80

Post by anonymousiam »

stinkbeetle wrote: post #79
anonymousiam wrote: post #50

The S-band uplinks are not typically used during operations. They're mostly used during transfer orbit operations and initial testing, and in emergencies when something goes wrong with the normal comms (safe mode). The S-band antennas on the satellite are typically omnidirectional, so they'll hear anything strong enough to overcome the noise floor. Those comms can be encrypted or in the clear, depending upon the situ…

> I'm not involved in this stuff anymore (now retired), but it's possible that the Starshield constellation supports transmitting on S-band (or L-Band) as a means to relay SGLS communications to satellites that are out-of-view. Having this capability would greatly benefit the workflow of transfer orbit operations and initial testing, by eliminating the constraint that the satellite must be in-view to communicate with…

Any sort of innovation may counter "standards", but without knowing the specific ITU terms for S-band, I can't say whether or not any regulation has been violated.

The fact that somebody saw something pointed at Earth on a frequency generally reserved for uplinks doesn't necessarily mean that it would interfere with other spacecraft receiving the signals from the ground. Starlink (and presumably Starshield) operates in LEO, below most other LEO spacecraft. Maybe they're using a dish or even a phased array antenna, and pointing down instead of up. If so, the probability of interference is low.

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