SpaceX F9 - Starlink Group 4-6 - LC-39A

[Grendal]

Launch Date: January 18
Launch Window: 7:04 pm EST (4:04 pm PST, 00:04 UTC on the 19th)
Launch site: LC-39A Kennedy Space Center, Florida
Core Booster Recovery: ASDS - ASOG
Booster: B1060-10
Fairings: Reused - Yes
Mass: 49 satellites - 15.5 tonnes
Orbit: LEO

A SpaceX Falcon 9 rocket will launch the 35th group of satellites (49 with lasers!) for SpaceX’s Starlink broadband network, a mission designated Starlink 4-6.

B1060 will be the fourth booster to reach 10 launches - if everything goes as planned.

 

[Cosmacelf]

So newer Starlink satellites seem to be getting heavier? Maybe optimizing the amount of propellant for station keeping among many other things…

 

[dazedNconfuzed]

Lasers. SpaceX - Starlink Group 4-5 - LC-39A

 

[Electroman]

What about all the ones that are already in orbit without the lasers? Are they going to deorbit them, or will these coexist with Laser equipped ones?

 

[Cosmacelf]

What about all the ones that are already in orbit without the lasers? Are they going to deorbit them, or will these coexist with Laser equipped ones?

Co-exist. They really only *need* lasers for the polar orbit ones. For the rest, it is a nice to have feature, but not essential.

 

[Electroman]

Great info thanks.

Is there any place I can read about how the lasers will be used? Rather what do you gain by using them, and also it puzzles me as to why one specific orbit over the others would benefit?

 

[dazedNconfuzed]

The non-laser Starlink satellites can only bounce signals from Earth to Earth. If a data packet need go farther, it has to bounce ground-orbit-ground-orbit-ground-orbit-... until it arrives.

Laser-enabled Starlink satellites can send, thru the vacuum of space, a data packet directly to the next satellite without having to bounce it off the ground. Result is a much faster data rate and reduced latency. Also allows getting data packets to another satellite if there is not a suitable ground station to bounce it off (say, over ocean or other no-ground-station area).

 

[Cosmacelf]

The non-laser Starlink satellites can only bounce signals from Earth to Earth. If a data packet need go farther, it has to bounce ground-orbit-ground-orbit-ground-orbit-... until it arrives.

Laser-enabled Starlink satellites can send, thru the vacuum of space, a data packet directly to the next satellite without having to bounce it off the ground. Result is a much faster data rate and reduced latency. Also allows getting data packets to another satellite if there is not a suitable ground station to bounce it off (say, over ocean or other no-ground-station area).

Not quite.

You need to remember that wireless bandwidth is constrained. There is no way Starlink would bounce the same data packet up and down through many satellite hops. The way it works normally is that a user terminal sends a data packet to the satellite, the satellite then relays it to a ground station which is an eight parabolic dish installation sitting on a 100 Gbps link to the Internet. From there it goes using ground fiber to the destination (which could be across the county). Remember fiber bandwidth is cheap, satellite bandwidth is expensive.

So, why lasers. Because there aren’t any 100 Gbps fiber links in the far arctic (and Antarctic), so there’s no ground stations to deliver the packet to. So to provide Starlink communication to such really isolated communities, the Starlink satellite relays the packet to the next Starlink satellite in its shell using point to point free optic laser until it gets to a Starlink satellite that can dump the packet off onto a ground station. This is also used for providing communications in the middle of the oceans.

 

[Grendal]

What about all the ones that are already in orbit without the lasers? Are they going to deorbit them, or will these coexist with Laser equipped ones?

All of it will be superseded by Starlink 2.0's when those will finally be sent up. They, according to Elon, will need Starship and Super Heavy to be deployed. So they are probably heavier, larger, and more features. And lasers - lots of lasers...

 

[EVCollies]

How long will it take for the new laser equiped sats replace the existing v1? Is this necessary for Starlink success or will a mix of sats be manageable?

 

[Cosmacelf]

How long will it take for the new laser equiped sats replace the existing v1? Is this necessary for Starlink success or will a mix of sats be manageable?

Reading between the lines from Elons tweets, Starlink needs scale to be profitable, which means many more times satellites in orbit and a corresponding larger number of customers. I am guessing that right now, they are still constrained on dish production.

Initial V1 sats supposedly have a 5 year service life. But again, lasers aren’t needed for the vast majority of customers. Most customers are near enough to a ground station for the data packet to make the one hop up to and down from a satellite. But for certain sub markets, like maritime ship communications, most of the fleet will need lasers. As will military (for wartime path redundancy and hardened and special purpose (Ie isolated) ground stations).

Slightly off topic here, but it isn’t just NASA that is being dragged into the commercial space era. The US military is too. Small cheap drones are becoming a viable military platform and the military has to figure out how to defend against drone swarms. Similarly, Starlink’s huge number of satellites is actually a very resilient communications platform. While China and Russia have fun knocking out geosats, Starlink will be resilient to any military attack just due to sheer scale.

 

[bxr140]

Similarly, Starlink’s huge number of satellites is actually a very resilient communications platform. While China and Russia have fun knocking out geosats, Starlink will be resilient to any military attack just due to sheer scale.

Starlink's vulnerability is Kessler. While not as immediate as a high energy impact to a non-constellation sat, a kinetic attack on a LEO constellation sat is far more uncontrolled...and the more satellites in the constellation (more specifically, in and around the attacked shell), the worse the propagation. That's one reason the constellations SDA and SMC (for instance) are contemplating are not nearly as large as Starlink. The pile up in the blizzard is going to be way worse during rush hour than at 3am, so to speak.

Also, at high orbits like MEO (mostly GPS) and GEO (all manner of state-run things) where its horribly impractical to attack with velocity, non-impact weapons are the way to go. The most basic is literally just putting something in front of the satellite, either stationkeeping in lock-step, tall-guy-at-concert style, or physically clamping on and deploying a shade. There's plenty of other fun ideas too...Paintball-sat flies around and covers up all the attitude control sensors so target sat doesn't know where it is. Chainsaw-sat snips off the solar arrays and/or antenna reflectors. Big-brother sat clamps on (to a main thruster or some other robust structure on target sat) and turns target sat away from the earth with a larger/stronger attitude control system.

 

[Grendal]

 

[808?]

 

[Grendal]

Less than 5% of violation.

 

[MyJoule]

The IR views of the launch were really cool, I wish we'd see those more often and we got video all the way to the 103rd landing of an orbital class booster! Way to go SpaceX. Never gets old with me

 

[Cosmacelf]

Wild that this is the 4th booster to land 10 times!

 

[Electroman]

Musk I believe said there is technically no limit to how many times a booster can be reused

 

[ItsNotAboutTheMoney]

Musk I believe said there is technically no limit to how many times a booster can be reused

Right, the 10 times was just an estimate related to needing more substantial refurbishment.

 

[Grendal]

Right, the 10 times was just an estimate related to needing more substantial refurbishment.

I think the 24 hour turnaround aspect was dropped and there is a thorough inspection and minor refurbishment done after every recovery. The minimum time seems to be around one month before reuse.