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There was a DARPA project called F6 for validating a similar concept. Spent a few million USD and ended with nothing much to show. Turns out formation flying is

There was a DARPA project called F6 for validating a similar concept. Spent a few million USD and ended with nothing much to show. Turns out formation flying is hard. Especially with satellites with limited orbital alignment capabilities, as the small uneven effects on the orbit from various sources (other planets, atmospheric drag, etc) eventually add up and you have to be able to correct the orbit from time to time to keep the formation. Apart from that, communications tech reliable enough for the kind of distributed in-orbit computation was still not there last I checked. I wonder if anything has changed in the meanwhile.

Zenst 6y ago
F6 - https://en.wikipedia.org/wiki/Fractionated_spacecraft https://en.wikipedia.org/wiki/Fractionated_spacecraft What has changed since then would be scale of alternative launch options as well as progress in satellite/radio tech and a bit smaller or lighter, sure does scale in savings. Perhaps with those factors it may well prove viable to revisit that. That an antenna's and phased arrays, been much progress even in the last ten years and might be that such visions need another ten years, but certainly seems a sound goal overall.
- jgilias 6y ago
  I completely agree that the goal is a good one. Downlink bandwidth is one of the most restricting bottlenecks limiting what we can achieve with satellites. It's absolutely worthwhile to revisit this idea from time to time. Someone should make a website 'are we async in orbit yet'.
- WrtCdEvrydy 6y ago
  I wonder if a self-healing mesh network would make more sense... just set up a mesh that readjusts for satellites going in and out of range...
Rebelgecko 6y ago
I heard this secondhand from a colleague who somehow ended up with one of the F6 cubesats sitting on an endtable in his office, but my understanding was that formation flying wasn't really what killed F6. Over the planned mission duration the satellites wouldn't have drifted apart too much, and even without thrusters there's tricks you can use to tweak orbital periods to keep them lined up. Even that is a moot point, since for F6 they didn't need to be lined up, a cluster was acceptable. The main problem came from the 4th F in F6, fractionated. The goal was to create a heterogenous network of satellites, built by a whole litany of manufacturers without even a common bus. That ended up being a solution in search of a problem. It made integration way more complex, which was exacerbated by the number of independent participants. The project spent a lot of time working on shared SDKs that would work across the constellation. In practice, there weren't really enough benefits over homogeneous constellations to make all the extra effort worthwhile. Instead of having 5 satellites with cameras beam their images to another satellite that determines which images are cloudy, it's easier to just have each satellite running identical code so it can figure out for itself which images are cloudy. On top of that, a homogenous network has advantages wrt survivability, manufacturing costs, maintenance, etc
- portillo 6y ago
  I agree, this was the real reason why the project failed. Moreover, it was not clear at all that fractionation would bring any lifecycle costs savings, neither that any of the alleged extra flexibility (and maneuverability, resiliency, maintenability, and other -ilities) would result in any added value for the missions. Fractionation is very hard,it introduces a lot of complexity in the design and interfaces, and it requires lots of coordination between multiple vendors. Project Ara by Google (a modular cellphone similar to Phoneblocks) also vouched for this idea of fractionation (and in fact was also led by Paul Ermenko) and was also cancelled.
agency 6y ago
Re: Communications tech, the 2nd generation of SpaceX's Starlink satellites are supposed to be able to communicate with each other via laser interlinks [1]. A friend of a friend works on the tech there and described the accuracy required for the lasers as being like shining a laser from LA to New York and hitting a specific window pane on the Empire State Building. [1] https://wccftech.com/spacex-starlink-satellite-laser-test/ https://wccftech.com/spacex-starlink-satellite-laser-test/

Zenst 6y ago

F6 - https://en.wikipedia.org/wiki/Fractionated_spacecraft https://en.wikipedia.org/wiki/Fractionated_spacecraft What has changed since then would be scale of alternative launch options as well as progress in satellite/radio tech and a bit smaller or lighter, sure does scale in savings. Perhaps with those factors it may well prove viable to revisit that. That an antenna's and phased arrays, been much progress even in the last ten years and might be that such visions need another ten years, but certainly seems a sound goal overall.

jgilias 6y ago
I completely agree that the goal is a good one. Downlink bandwidth is one of the most restricting bottlenecks limiting what we can achieve with satellites. It's absolutely worthwhile to revisit this idea from time to time. Someone should make a website 'are we async in orbit yet'.
WrtCdEvrydy 6y ago
I wonder if a self-healing mesh network would make more sense... just set up a mesh that readjusts for satellites going in and out of range...

Rebelgecko 6y ago

I heard this secondhand from a colleague who somehow ended up with one of the F6 cubesats sitting on an endtable in his office, but my understanding was that formation flying wasn't really what killed F6. Over the planned mission duration the satellites wouldn't have drifted apart too much, and even without thrusters there's tricks you can use to tweak orbital periods to keep them lined up. Even that is a moot point, since for F6 they didn't need to be lined up, a cluster was acceptable. The main problem came from the 4th F in F6, fractionated. The goal was to create a heterogenous network of satellites, built by a whole litany of manufacturers without even a common bus. That ended up being a solution in search of a problem. It made integration way more complex, which was exacerbated by the number of independent participants. The project spent a lot of time working on shared SDKs that would work across the constellation. In practice, there weren't really enough benefits over homogeneous constellations to make all the extra effort worthwhile. Instead of having 5 satellites with cameras beam their images to another satellite that determines which images are cloudy, it's easier to just have each satellite running identical code so it can figure out for itself which images are cloudy. On top of that, a homogenous network has advantages wrt survivability, manufacturing costs, maintenance, etc

portillo 6y ago
I agree, this was the real reason why the project failed. Moreover, it was not clear at all that fractionation would bring any lifecycle costs savings, neither that any of the alleged extra flexibility (and maneuverability, resiliency, maintenability, and other -ilities) would result in any added value for the missions. Fractionation is very hard,it introduces a lot of complexity in the design and interfaces, and it requires lots of coordination between multiple vendors. Project Ara by Google (a modular cellphone similar to Phoneblocks) also vouched for this idea of fractionation (and in fact was also led by Paul Ermenko) and was also cancelled.

agency 6y ago

Re: Communications tech, the 2nd generation of SpaceX's Starlink satellites are supposed to be able to communicate with each other via laser interlinks [1]. A friend of a friend works on the tech there and described the accuracy required for the lasers as being like shining a laser from LA to New York and hitting a specific window pane on the Empire State Building. [1] https://wccftech.com/spacex-starlink-satellite-laser-test/ https://wccftech.com/spacex-starlink-satellite-laser-test/