ABC News and io9 have some interesting coverage on how astronaut Dan Barry discovered that it is impossible to whistle while out on a moon walk.

Barry, who has seven hours of spacewalking under his belt, tried whistling during his spacewalk in May 1999. “I thought of it on the fly,” ABC News quotes Barry as saying. “It turned out that it didn’t work.” Why not? “You can’t whistle because the air pressure in the suit is only 4.3 [pounds per square inch], and normal atmospheric pressure is 14.7 psi, so there are not enough air molecules blowing by your lips to make a sound,” Barry said.

For the record: the tune he would have whistled could he have whistled was “Whistle While You Work.”

Barry, who earned his doctorate from Princeton in 1980, is just one several Princeton Engineering astronauts. Others include Pete Conrad *64, the third man to walk on the moon, Greg Linteris ’79 *90, James C. Adamson *77, and Gerald Carr *62.

By the way, the Trenton Times recently featured Robert Stengel‘s contributions to NASA’s space shuttle program. Stengel, a professor of mechanical and aerospace engineering at

Princeton University, designed a control system for the Apollo Project Lunar Module.