Launching Starlink with Starship

[STS-200]

If I remember correctly, that's not entirely true though. In the old classic single antenna sense, yes that becomes a problem. Then sats moved to stuffing the equivalent of antenna cones like a beehive to create spot beam send and receive zones on the antenna. But Starlink is an all phased array setup with the sat managing the link, so no physical cones but logically separating the spot beams at the antenna. There are 6 antenna plates on a Starlink currently that are jointly managed. It does help that the plates are known distances and tightly aligned to be cooperative, so extending that to antennas on close formation neighbors is a bit of an issue but functionally the same. A phased array antenna is really made up of thousands of tiny antennas logically controlled, so adding some more is a software and timing problem (typically made easier when the antenna distances are physically known/fixed and directly managed on the same electrical bus).

Interesting, I hadn't thought of that interpretation; flying the spacecraft in an array to expand the baseline.
It either requires very accurate flying or a lot of real-time computation.
Having an incomplete antenna, phased or otherwise, doesn't do much for SNR. Perhaps for very close-flying spacecraft (i.e. a relatively high antenna-to-void ratio) that could be solved with more power at the ground station.

Sounds like a project for Starlink V.4, or above, to me.
They could of course 'cheat' and do it the easy way - build a bigger spacecraft with bigger phased arrays, designed for launch on a bigger rocket.

[IainMcClatchie]

What is the point of the VLEO birds at 340km?

I think they're more likely there to soak up hot spots.  The ~550km constellation(s) should form a kind of baseload capacity, covering the entire geography fairly uniformly.  My guess is the VLEO birds will be tasked with hopping from one island of high demand to the next.  They can also be tasked to pick up unexpected surges in traffic.

How would this work?  Satellite constellations are generally terrible at concentrating bandwidth, and you are surely not suggesting that they would expend delta-V to deal with traffic surges.

[su27k]

Another thing to consider is that each plane only takes a small # of satellites, 20 to 58 in the 4,400 constellation. This means if you launch more satellites than this in a single launch, the rest of the satellites will need to drift to nearby planes, and this takes time, from weeks to months. This will cut into satellite's useful life time on orbit, and it slows down the deployment. This is why I'm skeptical that they'll launch hundreds of Starlink on a Starship. Seems to me the best way to take advantage of Starship is to launch much bigger and powerful satellites.

How much prop does changing planes quickly cost? There's got to be so much extra delta V available on an SS at low cost they could probably just get things where they want sooner

Disclaimer: Not sure if I'm calculating this correctly

Delta V needed to rotate the plane by theta = 2 * V * sin(theta/2)

smallest theta = 5 degree for the 72 orbital planes, V = 7km/s, this gives delta-v = 600 m/s, which is not insignificant. For a 200t Starship + Payload stack, you need ~35t of propellant with a Isp of 375s.

[su27k]

Another thing to consider is that each plane only takes a small # of satellites, 20 to 58 in the 4,400 constellation. This means if you launch more satellites than this in a single launch, the rest of the satellites will need to drift to nearby planes, and this takes time, from weeks to months. This will cut into satellite's useful life time on orbit, and it slows down the deployment. This is why I'm skeptical that they'll launch hundreds of Starlink on a Starship. Seems to me the best way to take advantage of Starship is to launch much bigger and powerful satellites.

Formation fly several small Starlink comsats to emulated a large Starlink comsat to increase the bandwidth available in a geographical cell area with the small Starlink comsats have more narrow coverage footprint. Will avoid the need to developed a bigger and more complex Starlink comsat.

I think FCC would have a big problem with this, since the # of satellites is limited by their license. Also formation fly is risky, you need to be very careful in order to avoid satellites crashing into each other. And some components are wasted in this scheme, for example formation flying requires each small satellite has their own star tracker, GPS, flight computer, etc, while the big satellite only needs one set of these (or 2 ~ 3 if redundancy is needed).

[STS-200]

Another thing to consider is that each plane only takes a small # of satellites, 20 to 58 in the 4,400 constellation. This means if you launch more satellites than this in a single launch, the rest of the satellites will need to drift to nearby planes, and this takes time, from weeks to months. This will cut into satellite's useful life time on orbit, and it slows down the deployment. This is why I'm skeptical that they'll launch hundreds of Starlink on a Starship. Seems to me the best way to take advantage of Starship is to launch much bigger and powerful satellites.

How much prop does changing planes quickly cost? There's got to be so much extra delta V available on an SS at low cost they could probably just get things where they want sooner

Disclaimer: Not sure if I'm calculating this correctly

Delta V needed to rotate the plane by theta = 2 * V * sin(theta/2)

smallest theta = 5 degree for the 72 orbital planes, V = 7km/s, this gives delta-v = 600 m/s, which is not insignificant. For a 200t Starship + Payload stack, you need ~35t of propellant with a Isp of 375s.

thirtyone was asking about quick plane changes, and su27k's answer was good; but there really is no need to do these brute-force plane changes.
RAAN can be drifted one way or the other with minor changes to the altitude of the orbit. After launch, this can effectively be done for free, by scheduling the manoeuvres which bring the satellite up to its operational altitude. In a 300km/52-deg orbit, the rate of precession is about 0.6 degrees/day different than at 550km - so simply waiting a month can give you a 20-ish degree change. Post-launch conditioning and testing takes a while, and with ion drive, these satellites can't raise their orbits instantly.

Even once at ~500-600km, a change of altitude of just 25km (about 30m/s for the round-trip) can change the precession by up to about 0.1 degrees/day (it depends on inclination), so drifting between planes isn't impossible.

[Zed_Noir]

Resurrecting this thread to proposed alternate Starlink deployment approach with the Starship.

Putting the Starlink flatpacks in external pods on the leeward side of the Starship.

Envisioning up to 3 pods that can hold up to about 120 Starlink flatpacks each in a stack with internal holding devices. Plus about 40 Starlink flatpacks in the nose section from a removable double stack horizontal deployer.

The Starship could be a slightly modified tanker variant with additional tankage.

The Starlink pods should be filled in a dedicated Starlink checkout and loading facility. Then attached to the Starship at the launch pad area with a gantry.

Deploying the Starlink flatpacks from a pod will be similar to a cold gas missile launch from a silo through port at the top of the pod.

Advantages to this Starlink deployment method are Starship chomper variant not needed, most Starships could be use for deploying Starlinks and a higher deployment launch frequency by using any suitable Starship that is available.

[beelsebob]

Resurrecting this thread to proposed alternate Starlink deployment approach with the Starship.

Putting the Starlink flatpacks in external pods on the leeward side of the Starship.

Envisioning up to 3 pods that can hold up to about 120 Starlink flatpacks each in a stack with internal holding devices. Plus about 40 Starlink flatpacks in the nose section from a removable double stack horizontal deployer.

The Starship could be a slightly modified tanker variant with additional tankage.

The Starlink pods should be filled in a dedicated Starlink checkout and loading facility. Then attached to the Starship at the launch pad area with a gantry.

Deploying the Starlink flatpacks from a pod will be similar to a cold gas missile launch from a silo through port at the top of the pod.

Advantages to this Starlink deployment method are Starship chomper variant not needed, most Starships could be use for deploying Starlinks and a higher deployment launch frequency by using any suitable Starship that is available.

I'm not sure what the advantage here is really.  Developing pods that change the aerodynamics of the rocket really significantly sounds as complex as, if not more complex than developing a simple fairing opening mechanism.

[oldAtlas_Eguy]

Every time I think about the door opening mechanism. I think of a door like the side door on a Caravan. It pops open and then traverses down the side towards the tail while being completely secured at all times so even a spin maneuver for the normal Starlink deployment could be done. Starlinks would be packed at a 90  degree orientation to the main acceleration to launch so they are pointing out the door. Then a Teflon like coated set of rails or sides of a container that has a stack is opened and the Starlinks are slung out. One container at a time. Then once all are deployed the containers close so they can be brought back for reuse. This method simplifies the payload handling so that the Starlinks are packed into the containers in a payload processing facility. Shipped out to the Starship even if it is sitting outside and then loaded into the Starship and fastened in place. Stacking container after container until the top of the opening is reached. It means that a very short turnaround could be supported for a Starship as in a week easily with this method. Also shipping these containers out to a sea platform could be supported where only the containers are transferred back and forth from the sea platform making easy to support with simpler shipping.

[Zed_Noir]

Resurrecting this thread to proposed alternate Starlink deployment approach with the Starship.

Putting the Starlink flatpacks in external pods on the leeward side of the Starship.

Envisioning up to 3 pods that can hold up to about 120 Starlink flatpacks each in a stack with internal holding devices. Plus about 40 Starlink flatpacks in the nose section from a removable double stack horizontal deployer.

The Starship could be a slightly modified tanker variant with additional tankage.

The Starlink pods should be filled in a dedicated Starlink checkout and loading facility. Then attached to the Starship at the launch pad area with a gantry.

Deploying the Starlink flatpacks from a pod will be similar to a cold gas missile launch from a silo through port at the top of the pod.

Advantages to this Starlink deployment method are Starship chomper variant not needed, most Starships could be use for deploying Starlinks and a higher deployment launch frequency by using any suitable Starship that is available.

I'm not sure what the advantage here is really.  Developing pods that change the aerodynamics of the rocket really significantly sounds as complex as, if not more complex than developing a simple fairing opening mechanism.

Developing a chomper hatch is simple?

Please discuss how loading and deploying a few hundred Starlink satcoms from dedicated  Starship variants is more efficient in launch rate than using any Starships with fittings for pods.

No matter what method SpaceX choose to deployed Starlink comsats from the Starship. It will not be simple, IMO. Starship has volume constraints on the handling and deployment systems  for the Starlink satcoms.
 

[Twark_Main]

Resurrecting this thread to proposed alternate Starlink deployment approach with the Starship.

Putting the Starlink flatpacks in external pods on the leeward side of the Starship.

Envisioning up to 3 pods that can hold up to about 120 Starlink flatpacks each in a stack with internal holding devices. Plus about 40 Starlink flatpacks in the nose section from a removable double stack horizontal deployer.

The Starship could be a slightly modified tanker variant with additional tankage.

The Starlink pods should be filled in a dedicated Starlink checkout and loading facility. Then attached to the Starship at the launch pad area with a gantry.

Deploying the Starlink flatpacks from a pod will be similar to a cold gas missile launch from a silo through port at the top of the pod.

Advantages to this Starlink deployment method are Starship chomper variant not needed, most Starships could be use for deploying Starlinks and a higher deployment launch frequency by using any suitable Starship that is available.

I'm not sure what the advantage here is really.  Developing pods that change the aerodynamics of the rocket really significantly sounds as complex as, if not more complex than developing a simple fairing opening mechanism.

Developing a chomper hatch is simple?

Compared to "a pod [that] will be similar to a cold gas missile launch from a silo through port at the top?" Yeah, actually.

The chomper is essentially the Minimum Viable Product of doors. It's simpler even than the Shuttle payload bay doors, which required complex three-way seals. Fewer hinges, latches, etc.

Starlink deployment can be performed with a simple tilt table + spin deployment.

Please discuss how loading and deploying a few hundred Starlink satcoms from dedicated  Starship variants is more efficient in launch rate than using any Starships with fittings for pods.

Please discuss how your "pods" are more efficient, i.e. how they justify their substantial design complexity.

No matter what method SpaceX choose to deployed Starlink comsats from the Starship. It will not be simple, IMO. Starship has volume constraints on the handling and deployment systems  for the Starlink satcoms.

Those constraints are precisely why the hardware will be simple, e.g. the existing "tension band" design.

[FutureSpaceTourist]

Cross-post from Starship prototype thread:

https://twitter.com/cosmicalchief/status/1549213709469360128

Caught several of these loads of Starlinks getting loaded into the payload integration box.  Video of the operation on the next WAI+, so check it out.
#Starbase  #Starship  #SpaceX
 📸 Me for WAI Media @FelixSchlang

[ZachS09]

Don't know if this has been answered:

How many Starlink 2.0 satellites can fit in Starship?

[AmigaClone]

Don't know if this has been answered:

How many Starlink 2.0 satellites can fit in Starship?

That might depend on how thick a Starlink 2.0 is. If the number is mostly limited by mass, I can see between 70 and 80 Starlink 2.0 satellites based on their weight, the weight of the dispenser, and the mass Starship can take to orbit.

[DanClemmensen]

Don't know if this has been answered:

How many Starlink 2.0 satellites can fit in Starship?

The SpaceX CGI video sjhowed the Pez dispenser pushing out 27 pairs of Starlink V2.0, for a total of 54. This is consistent with the available height ofthe dispenser within the cargo area of the Starship.

[ZachS09]

Don't know if this has been answered:

How many Starlink 2.0 satellites can fit in Starship?

The SpaceX CGI video showed the Pez dispenser pushing out 27 pairs of Starlink V2.0, for a total of 54. This is consistent with the available height of the dispenser within the cargo area of the Starship.

Given that each Starlink 2.0 sat is 1,250 kg, the total mass for 54 would be 67.5 metric tons (not including the dispenser).

[jackvancouver]

My big thing for 2.0 is more surface area. More receive surface area for UT transmissions means the beam doesn't need to be dead accurate like it had to be for the smaller older gen satellites.

[DanClemmensen]

My big thing for 2.0 is more surface area. More receive surface area for UT transmissions means the beam doesn't need to be dead accurate like it had to be for the smaller older gen satellites.

That's not the most important effect of a larger antenna on the satellite. User antenna pointing accuracy is pretty good. the biggest improvement is likely to be that a bigger antenna throws a smaller beam. They throw more, smaller beams so each beam has fewer customers and they get better spectral reuse. I don't know the specifics for Starlink, but a OneWeb satellite uses 16 beams to cover a rectangle centered roughly on its nadir. A larger OneWeb satellite could cover the same area with 32 beams, which would cut each beam footprint in half, allowing for twice the bandwidth.

[Ludus]

Don't know if this has been answered:

How many Starlink 2.0 satellites can fit in Starship?

The SpaceX CGI video showed the Pez dispenser pushing out 27 pairs of Starlink V2.0, for a total of 54. This is consistent with the available height of the dispenser within the cargo area of the Starship.

Given that each Starlink 2.0 sat is 1,250 kg, the total mass for 54 would be 67.5 metric tons (not including the dispenser).

This makes sense as a design goal, especially since Starship hasn’t flown yet and is far from optimized. A Starship load of V2 is then approximately the same number of Sats as an F9 load of V1.5, targeting roughly a tenth the launch cost for nearly 10X the throughput. Two orders of magnitude improvement.