Sunday, May 13, 2007

Planetary Defense Thoughts

I recently read a sci-fi book entitled Von Neumann’s War about Earth being invaded by machines modeled on Von Neumann’s hypothesis of using self-replicating machines for planetary exploration. One of the more disturbing aspects of the book was how long it took Earth to identify that a problem existed. The machines had colonized several planetary bodies & moons before they were detected during the invasion of Mars. Upon arriving on a planet they would convert every available bit of metal into machinery to make other machines thus acting like low-tech Replicators (who are likely a rip-off of the Von Neumann idea).

Why was this disturbing? Because by the time they invaded Earth, the machines had a massive logistics infrastructure within our solar system that we couldn't do anything about. Granted, Earth prevailed in the end (it was that kind of book) but it strikes me as incredibly worrying that something (or someone) could operate with impunity and setting up the means to defeat Earth in-system. Currently, we would essentially have no means of detecting them barring a fortunately placed space probe.

But it got me thinking….What could be done right now to either extend our ability to detect threats or better use what we have? Which lead me to the following ideas. I limited myself to two specific proposals. For a more general overview of the problems & strategies of Planetary Defense, I recommend Introduction to Planetary Defense by a group of engineers with experience in defense development.

I. Albedo Verification

One of the key methods of detecting machine presence in the book was to check for changing reflectivity of the bodies involved. Mars changed from red of iron ore to the gray of refined iron alloys. However, even though Earth possessed the ability to check the albedo of bodies in the outer solar system, it was not a regularly performed check. This is exactly how the machines were able to colonize so many places before they were detected.

Thus, I would say this is a relatively low-tech (within current state-of-the-art) method of checking for in-system infiltration on a massive scale. It should be the task of whomsoever is in-charge of planetary defense (Space Command, maybe?) to regularly perform these checks & for it to be done in secret.

Why secret? If the bad guys exist & have the ability to perform massive colonization of our outer solar system, then they can probably listen to our transmissions fairly easily. If the tests were public, it might lead to said bad guys attempting to conceal their efforts, which may very well make their actions undetectable to Earth authorities & greatly diminishing Earth’s ability to gather intelligence, and greatly diminishing the time Earth has to react to any detected threat.

This check should be performed semi-regularly on every moon & planet possible in order to ensure no significant changes have been made.

II. Improved DSN to In-Space SOSUS Network

During the Cold War, the United States Navy created networks of sonar bouys in the Atlantic Ocean in order to detect enemy submarines. It was referred to as the SOSUS Network. Currently, we have a Deep Space Network of antennae for communicating with distant space probes but no in-space assets solely dedicated to tracking natural or not where-ever they are in the solar system.

The creation of the SOSUS network was a technological feat of its time but it would still be several orders of magnitude easier than a space system. This is because the US knew the Soviets' technological capabilities and had a very good idea about what capabilities were necessary in their network. Also, they could track improvements to Soviet submarines through other sources like satellite coverage of known anchorages & human intelligence (ie – spies). Any implementation of this idea to space would have the opposite situation. With so many unknowns, the probes composing the network would have to be versatile, capable of detecting a variety of frequencies & phenomena, and easily adaptable by ground controllers in light of new information. This would greatly increase both the cost of each individual probe & make it less likely to be built. How do you create a network to detect what you cannot define?

One good thing, unlike albedo checking, a space SOSUS would not necessarily have to be secret because there is a very good side benefit to this system. These probes could be used to “cut their teeth” on impact detection for earth by asteroids & comets and acting as conduits for interplanetary probes & their communications. This could ensure international cooperation (as big enough asteroid impacts affect everyone & multiple international entities have interplanetary probes). It would also provide not a cover story so much as plenty of opportunity, motive & market to develop a more advanced Deep Space Network.

Off the top of my head, these probes should be robust, long-lived and versatile. Their positioning & density should reflect both Earth strategic concerns & ensure it is very difficult for a large portion of the network to be compromised in one instance due to any event natural or otherwise. It strikes me as especially important to ensure coverage of the opposite side of the sun from earth, the asteroid belt and the outer solar system especially areas where Earth has few interplanetary probes.


Notice that both of these ideas involve detecting a threat & not necessarily doing anything about it? Well, that’s because as of right now, there’s not much Earth can do. The Intro to Planetary Defense book explains in more detail but, barring something deeply unexpected, anybody capable of traveling between the stars is probably out of our league militarily. Honestly, all it would take is lobbing a few asteroids in our direction to wipe out our civilization and then wait a few decades for everybody to die off in the “nuclear” winter. Problem solved.

You know all those people accusing the government of running secret programs to fight aliens? They always say it like it’s a BAD thing. But truthfully, I’d feel a lot better knowing there’s a poor man’s SGC out there working toward ensuring that if anybody invades Earth, they get more than a few nasty surprises.

It’s not that I think there definitely aliens out there or that, if they exist, they are de facto hostile. I’m just one of those people who believe it’s better to plan for a rainy day than count on a sunny one.

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