It’s ancient speculation. Surely, even the earliest humans looked to the stars and wondered if perhaps somewhere “out there” someone was looking back at them. President George W. Bush has recently proposed a new initiative to build a moon base as a precursor to a manned mission to Mars. However, in spite of these lofty goals, numerous obstacles still remain before us. Associate professor of biological and agricultural engineering Ronald Lacey and fellow researchers at Texas A&M are working to help overcome some of those obstacles. “Right now, even when the planets are aligned right, it will take us about 900 days round trip to go to Mars,” said Lacey. “If we want to do these kind of extended, manned space flights then they will have to vastly improve life support systems.”
Astronauts cannot afford to bring enough provisions with them to survive extensive space flights. The substantial amount of money and room required to “pack” for such a trip is simply not feasible, but the answer to this problem may be found all around us. “If you look at life support, it’s air, food and water,” Lacey said. “If we could somehow grow plants on these trips or on the planets we visit then they could supply all these things.” Lacey has developed a low-leak, translucent chamber that allows long-term studies of plant growth under various pressure conditions. It is hoped that the chambers will offer insight into the response of plant life during extended space voyages.
Specifically, if NASA wishes to grow plant life on cold, barren planets, then low-pressure containment chambers will need to be used. The keywords here: low pressure. To eliminate leakage, the chambers will need to operate near the pressure level of the planet they are on, which promises to be a very low atmospheric pressure. “We have actually seen that plants do better under lower pressures,” Lacey said. “We have found that plants produce less ethylene, which allows for better growth, and at lower pressures we found better gas exchange and transpiration rates.”
Lacey’s plant chambers boast exceptional “tightness.” Even under large pressure differences, the plant chambers have minimal leakage, allowing for wide-scale growth testing under numerous pressure levels and gas compositions. The chambers are capable of maintaining pressures as low as 5 percent of atmospheric (14.7 psi) for weeks while exhibiting leak rates as low as 1.5 percent of the volume. The chambers were built to accommodate gas supply, nutrient supply, water drainage, instrumentation, fans and a cooling system. They were designed to support solid plant growth or hydroponic systems. They also ensure that the plants will receive ample light availability – almost the entire surface area allows for photosynthetic radiation.
While the initial motivation for developing the plant chambers was for extended space travel, they could soon become useful to biological research here on Earth. Due to the exceptionally low leak rate and ability to precisely alter the composition of gas in the chamber, environmental concerns such as the effects of global warming and air pollution could be studied more precisely.