Showcase highlights some unique technologies that NASA has developed
and which we believe have strong potential for commercial application.
While the descriptions provided here are brief, they should provide
enough information to communicate the potential applications of
the technology. For more detailed information, contact the person
listed. Please mention that you read about it in Innovation.
Super Mirrors at Low Cost
NASA Goddard Space Flight Center is seeking companies to explore
licensing a revolutionary process for precision optical polishing
of bare aluminum.
The benefits of this process include low weight; thermal stability—
bimetal thermal characteristics of nickel over aluminum are poor,
and pure aluminum mirrors offer excellent thermal stability; low
cost—plating aluminum surfaces with electroless nickel significantly
adds to the cost of the optic; smooth surface—the process
yields a 5-angstrom flat and spherical mirrors and 10-angstrom aspherical
mirrors, which are ideal for high-quality mirrors; and consistent
quality—plating electroless nickel onto aluminum can result
in faults that preclude using the optic, whereas this process consistently
yields a high-quality surface and form.
Manufacturers of optics, metal optics and diamond turning and polishing
equipment could license and incorporate this method into their products.
The high-quality optics achieved using this method can be used in
a variety of applications, including x-ray telescopes, cryogenic
instruments, interferometry and medical-imaging devices.
This method begins by using a single-point diamond turning machine.
Grinding cannot be used on bare aluminum—it leaves behind
particles that scratch the surface during polishing. Diamond turning
alone typically produces a 30- to 80-angstrom finish on standard
aluminum materials. Therefore, additional polishing is required
to achieve the needed smoothness for low-scatter, high-quality bare
The process uses a special compound to polish the mirror to a super
smooth finish. This compound not only offers superb lubricating
qualities, but it also contains suspended particles. These particles
are extremely hard and small, making the compound ideal for mirror
Flat and spherical mirrors polished using this process have a roughness
of 5 angstroms rms, while maintaining a surface-figure accuracy
of 0.125 of a wave peak to valley. Aspherical mirrors can be polished
to a 10-angstrom rms finish.
The major benefit of this innovative process is the ability to
make pure aluminum mirrors. Aluminum optics are less expensive and
lighter than optics made from other pure materials. Q
For more information, contact Joe Famiglietti, Goddard Space
Flight Center, Office of Technology Transfer, 301/286-2642, e-mail
Please mention you read about it in Innovation.