Innocentive has a "Pavilions" prize category that includes the following:
The Rockefeller Foundation:
$20,000: a plant oil stove that doesn't need to be cleaned every couple hours of use
$20,000: solar-powered wireless routers
$20,000: a dry-based biolatrines proposal
$20,000: "Safe and Economical Synthetic Route for PA-824, a candidate drug for tuberculosis"
$40,000: "Reducing Risk of Malaria with Solar Powered Device"
Clean Tech and Renewable Energy:
$30,000: Boston Energy Challenge for proposals for energy-efficient cooling and dehumidifying
$10,000: In Situ Analysis of NO3/NO2
$50,000: Rapid evaluation of nitrosamine content
... etc ... many more
... numerous prizes in the $10,000 - $50,000 range (plus the $1,000,000 ALS Biomarker prize)
In addition to the Pavilions, they also have several prizes for videos and other ideas to market and improve Innocentive itself.
Plus, there are the traditional categories (engineering/design, physical sciences, life sciences, chemistry, math and computer sciences).
I couldn't find a "space" or "aerospace" category, though ...