Washington, Jun 20 (IANS): NASA plans to install on the International Space Station (ISS) an instrument that will measure the temperature of plants from space, enabling researchers to determine plant water use and to study how drought conditions affect plant health.

The instrument, called ECOSTRESS, or ECOsystem Spaceborne Thermal Radiometre Experiment on Space Station, will hitch a ride to the space station on a SpaceX cargo resupply mission scheduled to launch from Cape Canaveral Air Force Station in Florida on June 29, NASA said on Tuesday.

Plants draw in water from the soil, and as they are heated by the Sun, the water is released through pores on the plants' leaves through a process called transpiration.

This cools the plant down, much as sweating does in humans. However, if there is not enough water available to the plants, they close their pores to conserve water, causing their temperatures to rise.

Plants use those same pores to take up carbon dioxide from the atmosphere for photosynthesis -- the process they use to turn carbon dioxide and water into the sugar they use as food.

If they continue to experience insufficient water availability, or "water stress," they eventually starve or overheat, and die.

The data from ECOSTRESS will show these changes in plants' temperatures, providing insight into their health and water use while there is still time for water managers to correct agricultural water imbalances.

"When a plant is so stressed that it turns brown, its often too late for it to recover," said Simon Hook, ECOSTRESS principal investigator at NASA's Jet Propulsion Laboratory in Pasadena, California.

"But measuring the temperature of the plant lets you see that a plant is stressed before it reaches that point," Hook said.

These temperature measurements are also considered an early indicator of potential droughts.

When plants in a given area start showing signs of water stress through elevated temperature, an agricultural drought is likely underway.

Having these data in advance gives the agricultural community a chance to prepare and/or respond accordingly, NASA said.

"ECOSTRESS will allow us to monitor rapid changes in crop stress at the field level, enabling earlier and more accurate estimates of how yields will be impacted," said Martha Anderson, an ECOSTRESS science team member with the US Department of Agriculture in Beltsville, Maryland.