The Lighting Research Center (LRC) is    part of Rensselaer Polytechnic Institute    of Troy, N.Y., and is the leading    university-based research center    devoted to lighting. The LRC offers the    world's premier graduate education in    lighting, including one- and two-year    master's programs and a Ph.D.    program. Since 1988 the LRC has built    an international reputation as a reliable    source for objective information about    lighting technologies, applications, and    products. The LRC also provides    training programs for government    agencies, utilities, contractors, lighting    designers, and other lighting    professionals. Visit

NASA Astronaut Dr. Nancy Currie, Ph.D. remembers just how surprising it was to trade in the flight simulator for the real thing in 1993.

"It's a shock on that first flight when you realize you're dealing with dynamic and extreme lighting conditions unlike any you've dealt with before," she says. "It's only on your first flight that you find out you were training in a pristine environment."

At 250 miles above the earth, astronauts experience "low-earth orbit lighting conditions" in a 90-minute orbit: 45 minutes of daylight and 45 minutes of darkness.

"Reflection and glare caused by spacecraft materials can cause significant problems," says Currie, who spoke at the "Bridges in Light" Symposium. It can affect:

The approach and docking of vehicles to orbiting spacecraft
Robotic tele-operations
Extra-vehicular operations (space walks)
"During a space walk, I ducked behind a console" because the glare was so jarring, recalls Currie, who operates the robotic arm in flight. "Lighting creates extreme challenges in spaceflight."

To help counteract the problem, the Canadian Space Agency created a space vision system that uses specialized targets-white-on-black and black-on-white, depending upon the light conditions, so that astronauts can see to get their jobs done outside the spacecraft.

Using accurately positioned video cameras as sensors, the image targets are determined pre-flight to help the astronauts properly direct their activities.

To plan for lighting conditions, NASA uses the Radiance Synthetic Imaging System developed by Lawrence Livermore National Laboratory.

"Within the last six months, we've done some preliminary real-time computational models," she explains.

Currie's most recent mission involved working on the Hubble telescope.

"The use of silver Teflon on the exterior turned out to be so reflective, we were concerned it would be blinding," she explained.

Even inside the space shuttle lighting is an issue.

"Interior lighting is pretty remarkable. We could get lost in the vehicle in the U.S. module. Lighting is so constant around volume, so you had no sense of up or down," she explains.

On the Russian module, interior lighting is handled differently: the relative ceiling is lit, the "floor" isn't light, and the center of the module is minimally lit.

"We never felt lost in the Russian vehicle," she explains.

Currie says the importance of space lighting research cannot be underestimated.

It is crucial to have:

An accurate model of orbital light conditions, for the safe and efficient space operations;
Key components of analysis for:
Light performance criteria
Computer-based models of the environment
Material reflective properties
Further research on improvements in real-time lighting simulations.
"Astronauts train in perfect lighting conditions, and have a great difficulty when confronted with real-time lighting," she says. One example: "As soon as we rapidly transition to darkness, we get the feeling of falling."

As for their night/day Circadian rhythm, Currie says light therapy was used in her 1998 and 2002 flights. "We would go into quarantine and try to trick our Circadian rhythm. We would darken the vehicle; put shades on or blinders," she says. Ultimately, "it's much harder to adjust to shift changes on Earth."

Currie expects the manned space program to resume in September 2004. If not then, November-or the following Spring. Her first launch occurred at night, but that will never happen again because NASA wants to be able to take images of take-offs.

"The challenge won't be technological. It will be organizational," she explains.

Currie and the crew that accompanied her were the last to use Columbia in 2002 before the shuttle's final, fatal mission in 2003.

To learn more about her flight on Columbia, read CNN.com's interview with her, published in 2002: Aboard Columbia: Nancy Currie.