Choosing materials for space structures

[astrogeek84]

Interstellar travel is mostly a though experiment at this stage (although NASA will be launching the solar sail SunJammer in a couple of years). My question is a very broad one about what type of materials would be well-suited for structures to support interstellar travel.

Any human habitat would be pressurized (to ~14-21 psia) and (probably) made out of steel (like the Centaur, the upper stage of the Atlas V rocket) or aluminum in the shape of a cylinder. What could be the expected life of such a structure in this environment (corrosion due to moisture, radiation, etc.).
Is there an "ideal" material for this application? How might you estimate a usable life for the structure? I've never really seen much data where material performance is extrapolated to centuries (rather than years). When a structure of this sort does fail, what would be the failure mode?

 

[Astronuc]

Usually for spacecraft , one wants a high strength-to-weight ratio. One wishes to minimize mass (propulsive energy/power requirements) that must be transported long distances.

We do not have much experience of highly engineered materials (advanced alloys and materials) over more than a few decades.

Fatigue/creep, and possibly erosion/corrosion, would be limiting over long periods of time.

Most applications of spacecraft are within the neighborhoods of the Earth or solar system, so the lifetime might be 7 years, 10 years, or 30 years, or mission time + margin. We are a lot smarter now than we were when the Voyager spacecraft were launched.

SPACECRAFT LIFETIME
The Voyager spacecraft launched in August and September of 1977 and spent more than 11 years exploring the likes of Jupiter, Saturn, Uranus and Neptune before officially heading off toward interstellar space in 1989.

. . . .

http://voyager.jpl.nasa.gov/ spacecraft /