NSSO on Space Based Solar Power

apsmith writes "About a year ago some of the people at the US National Security Space Office began looking into space-based solar power (SBSP) as a technology in the near-term strategic interests of the United States. At first the participants were skeptical, and the "phase 0 study" went along with no official funding. In a rather innovative move, they organized the study as a series of internet-based (bulletin-board and email) discussions, with the wordpress site open to the public, and a closed experts-only discussion using Google Groups. Initially expecting only a dozen or so interested parties, the discussion grew to include over 170 people with past expertise and interest in the issues. The final report was released Wednesday morning; it provides an excellent broad-brush review of the status of SBSP, showing immense potential, but also a number of challenges that appear only surmountable with a strong government commitment to the project. The big question is where it goes from here — NASA? DARPA? The new ARPA-E? Or something new? I was able to attend the press conference, which included Buzz Aldrin in an announcement of a new alliance to push for implementing the recommendations of the report."

Comments

The difference between... cannot go wrong

[cumin]

Douglas Adams - "Mostly Harmless"
- The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair.

Lets build in some redundancy shall we? (Just in case.)

I think you covered the list pretty well but corrosion is also a factor that space should mitigate. Well, mostly aside from the wandering bit of space debris.

I haven't RTFA, probably won't, but I'd like to throw in the additional suggestion we look into Von Neumann devices to build most of the components on a lunar base. (Earth first, and strip-mine the moon later.)

Re:Ok, someone explain it to me

[Lloyd_Bryant]

There is no nighttime in space, nor any clouds, nor any seasons, nor any atmosphere. Solar panels in orbit deliver full power 24 hours a day 7 days a week 365 days a year with no need for fuel or maintenance. And they don't have to be, and probably shouldn't be, in orbit. Inject them into an orbit between Venus and Mercury, or closer still. Solar radiation falls off with the square of the distance. The closer we get them to the sun, the more power they will generate, by orders of magnitude. First off, putting them somewhere other than Earth orbit is silly - yes, you can get more energy from the Sun, but how do you transmit it to Earth? The microwave (or whatever) beam will also fall of with the square of the distance.

And how exactly do you keep the power beam locked onto the target, when the target is on a sphere rotating once per day?

Putting them in equatorial geostationary orbits is *much* simpler. You'll lose a small amount of generating time each day (while the station is in Earth's shadow), but if you schedule as much of your maintenance as possible during this time, the effect is minimal.

And maintenance *will* be required, for the foreseeable future. Someday we may be able to build solar cells that don't need to be periodically replaced, but not today.

Furthermore, it's been noted that Earth orbit is "halfway to anywhere in the solar system" (attributed to Heinlein). So we'll need serious orbital capability to build these things, regardless of where we put them.