Rapid Fabrication of High Stability Optical Mirror Blanks

In the 2010 Decadal Survey, NASA identified several needs for next generation space telescopes under TA08. Of the top technical challenges, rapid time scale development was identified as the first need, both in order to explore innovative ideas and to fit the exploration within an Explorer or a Discovery class mission. The number two need was high performance, stable, low areal density optics normal incidence optics that could be manufactured at lower cost. These three technologies allow diffraction limited visible wavelength telescope mirrors at a cost and schedule that is an order of magnitude lower than current technologies. The lower cost makes large segmented telescopes affordable. The lower cost and schedule allow a significant expansion of what can be addressed within the cost caps for Explorer and Discovery class missions. The ability to rapidly fabricate these mirrors takes a fragile, expensive, and long lead item off of the critical path and allows a significant reduction in the quality oversight associated with protecting items that have a multi-year lead time. NASA clearly needs a better solution. The goal of this program is to reduce both cost and schedule by an order of magnitude by changing the technologies used to build lightweight mirrors.

Mirrors for commercial remote sensing satellites have requirements that are very similar to NASA UVO telescope mirrors. This applies to larger systems, such as those flown by DigitalGlobe, as well as to smaller systems, such as those flown by SkyBox. For systems like these, current technology imposes costs beyond just the telescope costs. The long lead time of mirrors for telescopes leads to spiraling costs. To protect a long lead, critical path item programs add quality oversight, which can add 60% to the cost. This makes the telescope even more expensive and demands additional reliability and quality oversight. The telescope costs are particularly painful for commercial ventures that must turn a profit in order to attract investment. For example, Planetary Labs requires lightweight telescopes for asteroid surveys. These systems need to be diffraction limited and they are both cost and launch mass sensitive, since they are trying to do surveys at a significant standoff and on a limited budget. More »