In the Lab

In-Flight Research

The Scientific Balloon Program of CNES (France's National Space Research Center) has developed the Infrared Montgolfiere (MIR), an unmanned hot air balloon, which could assist in monitoring atmospheric changes. An "open" hot air balloon, the MIR uses passive heating, through solar and infrared terrestrial radiation, to make the air in the balloon warmer than the ambient air and give the balloon lift.

The first MIR designs were created by CNES in the 1970s, in an attempt to increase the duration of balloon flights and to solve some of the problems encountered with Stratospheric Pressurized Balloons (SPBs). The MIR flies at 92,000 feet in the day and 66,000 feet at night because of the differences in day and night temperatures, differing from SPBs, which fly at a constant level. The Infrared Montgolfiere can carry 110 pounds of equipment in its gondola, allowing it to fly over large areas of the Earth. SPBs can only carry about 33 pounds for extended periods of time. Other recent technological improvements, such as weight reduction and improved thermal modeling, have allowed CNES to use the MIR for research in Arctic regions.

The MIR Infrared Montgolfiere was tested on an around-the-world flight, launching last February from Bauru, Brazil. It successfully circled the Earth from east to west, passing over South America again, before becoming lost in the Pacific Ocean. But by completing the journey, the balloon broke a 1989 record for flight duration and set a new world record at 71 days for balloon time aloft. The previous record holder, the 1989 MIR balloon, had circled the Earth three times in 69 days.

The MIRs are able to take measurements in the low stratosphere and high troposphere, which are nine to 16 miles above the Earth's surface and difficult to observe by satellite. They can fly over varied geographical areas and study atmospheric transport, chemical emissions and convective activity.

New developments to the MIR balloon are adding to its flight time and dependability. The CNES has introduced a technology that uses ribbons for the assembly of MIR's panels. Developed in conjunction with the French company Zodiac International, the adhesive polyester ribbons can improve the reliability of the balloon's envelope. In addition, new measuring instruments on board the gondola can transmit data received from Inmarsat satellites. The gondola uses a remote command from the ground, relayed by Inmarsat satellites, to more accurately control the flight of the MIR and for on-board experiments.

Objectives of the missions carried out in late 2000 and early 2001 in Bauru included the validation of the design and manufacture parameters of MIRs; a research program on exchanges between the troposphere and stratosphere; and remote measurement and control of the gondola via Inmarsat.

The MIR balloons, used for the study of the atmosphere and stratospheric chemistry experiments, are a relatively inexpensive means of conducting atmospheric research. The success of the Bauru flight is an encouraging development, with potential for future progress. The research carried out by new hot air balloons can verify predictions from meteorological models and satellite measurements on the composition of the atmosphere.

For more information, visit CNES at www.cnes.fr/WEB_UK.

Plutonium Cleanup

Bioremediation efforts may be strengthened by the discovery that a microorganism can take up plutonium (Pu) in the same way that it ingests iron. The technique, demonstrated by scientists at Los Alamos National Laboratory (LANL), could enhance bioremediation and help to more accurately predict how plutonium and other actinides interact with their environment.

LANL researchers studied the microbe Microbacterium flavescens, which takes in nutrient iron through siderophores - low molecular weight-chelating agents that bind with iron and transport it into the microbe. M. flavescens is a relatively common microorganism, and its inability to produce siderophores allowed researchers to accurately control siderophore concentrations in research.

The research team, led by Mary Neu, noted the similarities in the structures of the complex that iron forms with siderophores and the plutonium-siderophore complex, leading to the theory that bacteria could take up plutonium. The team found that the microbe could in fact take up plutonium, though at a slower rate than it could absorb iron. They also discovered that the microorganism could not absorb uranium because of differences in the uranium-siderophore and iron-siderophore complexes.

Actinide contamination in groundwater and soils threatens the environment and human health. In 1993, the U.S. Department of Energy (DOE) identified a number of sites with substantial plutonium and uranium contamination. Wildfires near the LANL Laboratory and Idaho National Environmental Engineering Laboratory have increased concerns about actinide contamination and its migration into soil. Further remediation efforts will be required to clean many contaminated sites. New bioremediation efforts and a better understanding of plutonium environmental chemistry could be the first steps.

However, M. flavescens is not alone in its ability to take in plutonium using siderophores. Anna Palmisano, program manager at DOE's Natural and Accelerated Bioremediation Research Program, says that Neu's research is a "breakthrough" and could point toward new ideas in plutonium containment. "Could we chelate and mobilize plutonium? Or sequester it with microorganisms to produce a biobarrier? I'm not saying we could do this tomorrow, but we can begin to think long term," Palmisano said.

The interaction of Pu-DFOB with M. flavescens "represents a potentially universal system" and speculates that other bacteria, fungi and plants will be able to ingest plutonium, according to Neu. She says that the research on M. flavescens "suggests a major pathway for environmental mobility and entry into the food chain for plutonium."

For more information, visit LANL at www.lanl.gov/worldview or DOE's Natural and Accelerated Bioremediation Research Program at www.lbl.gov/NABIR.




This article originally appeared in the October 2001 issue of Environmental Protection, Vol. 12, No. 10, p. 10.

This article originally appeared in the 10/01/2001 issue of Environmental Protection.

About the Author

Jeff Wilson is managing editor of Environmental Protection.

comments powered by Disqus