All signs are go for the Thursday morning launch of a mission that scientists hope will provide crucial insights into climate patterns at the global and regional level, and even raise warning flags about looming issues with water.
"This mission could not be more timely in my view," said Kent Kellogg of JPL, who is serving as project manager for the satellite observeratory designed to map moisture in soil around the globe.
Moisture in the top two inches of soil is seen as a crucial indicator of what is happening in the water cycle, said Dara Entekhabi, an MIT Professor of Civil and Environmental Engineering who leads the mission's science team.
The water cycle is tied to the cycles of energy and carbon, which is implicated in climate change.
The potential applications include improved forecasting in general, and specifically more capability to forecast increased regional risk of drought and floods.
In other words, how will the impacts of global climate change vary by region?
"Is it going to lead to more extremes in water? That's where the impacts are. Not necessarily
globalaveraage temperature," said Entekhabi, who sees regional changes to water cycles as perhaps the most significant manifestation of climate change. "What's going to happen to droughts and floods in my region?"
With the observatory designed to use two means for measuring soil via microwave radiation--active radar and a passive radiometerassive--it's been dubbed SMAP: Soil Moisture Active and Passive.
The SMAP observatory will be launched from Vandenberg Air Force Base and carried into orbit by a Delta rocket.
A three minute launch window opens at 6:20am Thursday morning. The weather forecast is favorable. As of Tuesday's briefing, there was only a 10 percent chance of weather forcing a launch postponement, said Air Force First Lt. John Martin, the launch weather officer at Vandenberg.
Condensation trails from the rocket sky may be visible in the southwestern sky more than one hundred miles away in Los Angeles.
Use of two instruments will enable the observatory to focus on areas as small as six miles
across, but at the same time, cover enough ground to map the globe's surface every two days near the poles and every three days near the equator.
It will keep gathering data day and night.
"It's a mapping instrument that enables us to see through things that blinded us before. It can seen through clouds and in darkness," said Entekhabi.
The NASA mission will cost $916 million, according to the space agency. The observatory was assembled at NASA's Jet Propulsion Laboratory on the border of Pasadena and LaCanada.
SMAP reflects a commitment by NASA to advance Earth science by investigation from space. NASA's "Earth Right Now" initiative carries the tagline: "Your planet is changing. We're on it."
Dating back to an earlier proposal that never came to fruition, a mission to track soil moisture
has been in the works since the turn of the millennium.
After launch, perhaps the most nerve wracking portion of the mission will be the unfolding and deployment of the elaborate antenna 20 feet across to be supported by boom that will rotate at 14 rpm to increase the coverage range of the instruments.
Nearly two months has been budgeted for that process.
Because it is so crucial to the mission, the deployment process has been pre-tested from start to finish 18 times, Kellogg said. The testing revealed some bugs that have been fixed.
"So we have a lot of confidence," Kellogg said.
In trying to underrstand the interractions between the planet's water, energy, and carbon cycles, it
has become clear that "soil moisture is the key variable," Entekhabi said.
"Soil moisture has the ability to have significant impact on people's lives. And this mission is going to help us understand and forecast that better. It's going to benefit the lives of just about everybody on the planet," said Kellogg.
Soil moisture is already closedly tracked in developed agritultural regions, but in vast areas remains unknown.
Entekhabi said one of the challenges in modeling global warming has been lack of data from so-called "boreal" forests in the extreme northern latitudes, where the carbon cycle depends on the freezing and thawing of water in the soil. After thaw, vegetation begins absorbing consuming carbon, but stops at the next freeze.
The lack of data and uncertainty contributes to the "missing carbon problem."
SMAP is designed to detect the onset of thawing and freezing, which Entekhabi belives will go a long ways to solving the mystery of the missing carbon.
"I think we're going to understand how our globe works," predicted Entekhabi.
