Sunday, July 5, 2015

Cost-Benefit Analysis for Stellar Travel

Cost-Benefit Analysis (CBA) is a collection of techniques for figuring out if the benefits of some project are greater than their costs. They are typically done at the stage of a project before the large expenditures arise, but after enough preliminary work has been done to frame the project. The preliminary work has to be firm enough to get rough estimates for the different expenses that the project will require, and the goals of the project have to be described well enough that quantitative benefits can be estimated. Note that this is a quantitative study, meaning that any benefit which is intangible is also inconsequential. The kind of benefits that people throw around in popular discussions for doing something often do not have any tangible benefits that can be estimated. Some of the hardest work in doing CBA is figuring out what good the project actually will do. Some visionary will have an idea, sell it to someone with disposable funding, and the framing begins. But soon it becomes time to do the CBA, and if the CBA says the benefits far outweigh the costs, the project is a go. If it is the other way, and the benefits are small compared to the costs, the project has little chance of moving forward.

In order to get some inkling of what a stellar travel CBA might show, let’s think about the process of obtaining an estimate for it, just as if we were advanced aliens. We have little data. A current interplanetary explorer now costs in the multiple billions, and they head out only some tens of AU. These probes are largely designed from scratch, and every item is individually designed and tested before being integrated in a very careful fashion. Because everything is a one-off, the costs are necessarily high, compared to the next B-767. If some aliens were planning to build a hundred starships of identical design, they could pro-rate the design and initial testing over the whole hundred, reducing cost markedly. In order to give the best face to stellar travel, they might consider that the rules of the CBA are that there will be a hundred of them built. Also assume they will be designed identically, with the ones destined for more distant stars setting the design criteria. Let’s assume 200 light years as the maximum distance for the ship.

To frame the design, we need to set requirements for the ship, and these are derived from the ship’s mission, which is an elaboration of the ship’s goals. One common mistake in CBA is taking the success of the project as a goal. It is not a goal, as there is no benefit that can be assigned to success that is not derived from more fundamental, outside the project details, goals. So, what are the goals of stellar travel?

One goal is curiosity. Perhaps we want to learn more about an exo-planet than we can determine by observing it from somewhere in or near our solar system. Suppose this is a goal, and then we must ask how much is this information worth? The value of information does not depend on the cost of obtaining it, but on the use to which it might be put.

Consider an unrelated but illustrative example. Two identical gold mines are found somewhere by mining companies. One takes a single explorer two weeks to find, he got lucky. Another one was only found after ten year-long expeditions with ten people each. Which one has the greater benefit? The gold mines are identical, meaning they have the same amount of gold located at the same depth in the same type of rock, with the same water resources available. The first one is a week’s trek from where the solo explorer started. The second one is a month’s travel from the port where the larger team was amassed. The first is more valuable, as the mining company is interested not in how much gold they can mine, but what the net value of the gold is. The first mine is more accessible, and the cost of developing the mine and processing the ore will be less. Whether or not the second one is ever dug depends on how much the cost of getting all the mining equipment to the remote area is. The example was just concocted to show that something obtained closer may be much more valuable, and that the net costs of something that is intrinsically quite valuable, gold, may be negative.

Consider an alien civilization that has explored its solar system, and has achieved asymptotic technology, the end result of technology development. They can build a starship, and have laid out some plans for it, enough to get estimates of the cost to build it, staff it, launch it, and recover it if it is a round trip vessel. The team doing the CBA wants to know what will be done with the information recovered from the trip. They will quantify its value.

In and of itself, the information is useless. They have already figured out all there is to know theoretically about planets, their formation, their geology, and anything else an advanced civilization classifies as planetary science. The only thing they would gain is knowledge of where on the spectrum of possible planets this one is, and they already know something about it from observing it. The same goes for any biologics living on the planet. They understand all they or anyone could about biology, and finding out which particular life-forms happen to have evolved on the remote planet doesn’t provide any useful information, no matter what they are.

There is likely no material on the remote planet that would be worth shipping back. You don’t have to do a real CBA to know that shipping costs would make the net worth negative. Since they have accomplished their technology development, they have developed substitutes for any element that is not sufficiently present in their solar system.

The information about the planet would be of use in designing a follow-on ship to go to the same planet. But this is a cascade question. If the value of even more information from a second ship is zero or negative, scaling down the cost is not going to turn the CBA into advocating the project be built. At this point, the CBA team would declare a default result, with no value to the mission. No need to frame the project or to continue estimating costs. Just report the results.

One other possibility exists. The only remaining benefit might be colonization, and in that instance, the value of the information from the first ship leads to an improvement in a second ship, and on until a colony ship goes. Then the value of the planet as a new home world can be estimated, perhaps equal to that of the original home minus the costs of developing it. So if asymptotic technology has been achieved, the only use that could possibly meet CBA criteria for project continuation is a colonization project, or let us say, the various stages of a colonization project. This is a bit startling.

Since we on Earth are living during the short window of technology development, everything we look at is distorted by the idea that this is normal or long-term. It is quick in the lifetime of a species, maybe a millennium compared to a hundred millennia. Once the transition is passed, everything else looks different. Curiosity and exploration don’t have any pull after the transition. Colonization appears to do so, but the costs involved will depend greatly on how similar the new planet is to the last one. Terra-forming is a long way further up the technology learning curve from our current position, and no estimates of the costs of it would be reasonable, especially when most of the materials would have to obtained in the distant solar system, rather than trucked along in the starship. Even though no quantitative results can be obtained, an insight comes out of the mechanics of CBA.

The implication of this analysis is that if an alien ship shows up in our solar system, they are here to stay. Perhaps uninhabited planets are much cheaper to colonize, and so we have been fortunate so far. This is fertile ground for Great Filter thinking. There are a lot of ideas knocking around about why aliens have not shown up here on Earth, and why SETI draws a blank. One alternative is that the aliens of the galaxy are good at CBA, and base their decisions on them. If the CBA result for stellar traveling is negative, they all decide to stay home. We should hope so.

No comments:

Post a Comment