DARPA Funds Development on Modular Satellite Network

coondoggie points out a Networkworld story about plans for modular satellite technology which is intended to replace modern, "monolithic" devices. The project hopes to solve issues of scalability and reliability by separating the typical satellite systems and allowing the different modules to change function when necessary. Quoting: "According to DARPA such a virtual satellite effectively constitutes a "bus in the sky" - wherein customers need only provide and deploy a payload module suited to their immediate mission need, with the supporting features supplied by a global network of infrastructure modules already resident on-orbit and at critical ground locations. In addition, there can be sharing of resources between various "spacecraft" that are within sufficient range for communication. DARPA said ... within the F6 network all subsystems and payloads can be treated like a uniquely addressable computing peripheral or network device. Such an approach can provide a long sought after "plug-n-play" capability, according to the agency."

Comments

Bad idea jeans

[Protonk]

there is no good reason for this to be a huge research priority (although arguably, it isn't huge). When I first read the summary, I thought that DARPA was funding a next generation version of Hughes Aerospace's 'modular' satellites system, where Hughes builds 1 bus and offer 1 of three payload configurations to customers.

But I'm more confused as to the goals of this project. I read a few of the linked pdf's and true to form, the government request for grant applications were not enlightening. The best I can hash of it seems like this:

DARPA wants to build and test satellites that are placed into orbit in a micro-constellation of sorts, communicating between various parts via wireless signals. Let's leave aside security and interference concerns, because they are--frankly--minor. My primary concerns would be duplication of elements. Assuming that they still have traditional roles for satellites, such as remote imaging and relay, payloads still need to be handled nicely. The camera for the remote sensing system needs to:

1. Know where it is.
2. Know where it is pointing.
3. Point there without too much wobble.

The first 2 can still be done with a distributed satellite--you just put the start tracker and the computational hardware on another cluster. The second requires that you keep the stabilizing hardware on the same bus as the payload. Beyond that, how will they manage stationkeeping? Each microsat would have to be fitted with jets or be replaced in a few years time.

Can anyone fill me in on what I am missing here?

FYI

[djupedal]

Link to the original 7.2007 funding announcement WORD doc directly from DARPA...

Gotta' get going on that marine turtle study grant before they give that one away to someone looking to make soup...darn!

Cluster networking

[n3tcat]

So after reading this, I had the random thought of cluster networking and whatnot, and it made me wonder if the satellites would ever have any spare CPU cycles. If so, I wonder if they handle helping some of the @home projects (folding, seti, etc).

Re:Robustness

[Protonk]

That strikes me as BS. DARPA has been working on ASAT and defenses against ASAT since before it was DARPA. We had to rename all of the ASAt vehicles when Clinton came to office so they didn't sound like purely cold war projects. To think that we have only now come up with this "big sky" approach to defending against ASAT is silly. ASAT is a fact of life when dealing with modern enemies. Hell, we used to worry about russians detonating nuclear weapons in their own satellites just to take ours down. How is a microconstellation going to fix that?

and BTW, I read the article, I just don't feel the need to repeat their stated claim when arguing the negatives, thanks.

Here's my point. In order to hold stationkeeping--in other words, if you give a shit about where your orbit is and how long you can maintain it, each piece of that micro-constellation needs fuel and thrusters. The biggest pieces are still going to be:

Payload
Fuel
solar Panels

Each component is going to need to replicate those, introducing new chances for failure. On top of that, components and satellites are intricately power and heat balanced. Heat dissipation is very tighly controlled and often certain components are paired well with others in order to radiate heat away at a given rate so that the craft doesn't cook itself and that cyclic stresses don't become a problem for long serving craft. This means that each of those components needs to be engineered specifically where only one did before on top of duplicating hardware.

Also, there are still critical components. There will only be one tranceiver (large). That's a critical component. There will be only one payload microsat. There will be (assuming wireless power transmission) only one power generating microsat. All of those are critical to operation. It isn't more secure and robust just because they say it is. Sheesh.

Now instead of one computer to check for bugs and secure against radiation we need 8-10. instead of engineering one satellite we engineer 8-10. If the government wants to spend more money, then be my guest, because that's what this will do.