The Race for the Space Curtain Wall is on!

The future of man in space must certainly include specialized glass. We predict that as man builds his structures in space they will include a "Space Curtain Wall" made with metal switchable mirrors. The race
is on to see who will be the first to use this novel application of glass in space.

The race is on to develop the next generation of energy-efficient windows, and it has a new entrant: transition-metal switchable mirrors (TMSM’s). TMSM’s are glass panels with a coating that can switch back and forth between a transparent state and a reflective one. Recently new advances in the field of glass and mirror making are stirring up interest throughout the industry that has the potential to reshape the way we
see our world and how the world sees us.
Researchers in the developing new building technologies department at the Lawrence Berkeley National Laboratory, under a grant from the Developing New Technologies division of the Department of Energy,
have tested an electrochromatic film that will allow mirror switchable to clear panes to be produced.
Switchable mirror films with variable optical properties are attractive materials for regulation of light and
heat transfer in buildings, airplanes, and space products. They may have other applications in sensor technology, data switching, and display technologies.
These switchable mirrors are based on hydrogen absorption and desorption. They are not new technologies; the first (TMSM’s) were created in the 1990’s and were composed of rare earth metals.
Recently, T.J. Richardson at Lawrence Berkeley National Laboratory (LBNL) and others reported switchable mirror effects in thin films of magnesium and three dimensional transition metals which avoid the use of
rare earth metals and may therefore be more cost effective and stable.
Various technologies offer different approaches to diffusion and diffraction of light and heat radiation.
There are many different products on the market today and some not yet on the market. These include: electrochromics/ electrochromatics, suspended particle displays (often called SPD glass), liquid crystal photochromics or photochromatics, thermotropics and reflective hydrides. Metal hydride film technology
may be among the most significant advances in the effort to reduce energy use for heating and cooling in buildings. There may be many other applications for transitional switchable metal mirror technologies.
Many glass companies worldwide have pursued electrochromic windows over the past three decades.
Most of them have given up on absorbing-type electrochromic windows, but are waiting to see if break- throughs occur. The SAGE windows turn blue to absorb light when desired. They are an all solid-state
design, which makes them very durable, even in direct sun and heat. Scientists are also working on a
solid state system, and believe that their reflective nature will make them cooler when the sun is intense.
This is also a big plus for automotive uses, as it could reduce the size and utilization of air conditioners,
which account for as much as 10% of fuel consumption in the Southwest.
In addition to the obvious potential uses in airplane windows (especially to protect pilots of large aircraft,
who sit in direct bright sunlight much of the time) and in helmet face shields, heat control for satellites (which get very hot on the side facing the sun and very cold on the other side, while the instruments inside must be kept within a narrow temperature range) is a major problem that could be addressed this way. This is the
sort of high-value application that may be among the first to make it to the market.
Currently research into transitional metal switchable mirror technology is ongoing, according to T.J.Richardson (LBNL) “We have a small prototype development project ongoing at LBNL that is supported
by the Building Technologies part of the Department of Energy, which sponsored the original research.


Researched and written by
Kevin Meaney
Metal switchable mirrors in space.

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