Research satellites to ride in tandem to orbit

A drawing of the Jason-1 satellite

By Amanda Barnett
CNN

(CNN) - Two satellites scheduled to ride together into space in September will give scientists new information about the Earth's upper atmosphere and the oceans. The pair of probes is scheduled to be launched no earlier than September 13 from Vandenberg Air Force Base in California on a Delta II rocket.

One satellite, the $300 million Jason-1, eventually will replace the TOPEX/Poseidon satellite that has been monitoring the oceans for more than 8 years.

TOPEX has improved global climate predictions and monitoring of weather events such as El Nino, according to Lee-Lueng Fu, project scientist for Jason-1 at NASA's Jet Propulsion Lab in Pasadena, California.

Jason-1, a joint project with France, will measure sea levels, help scientists map the topography of the oceans, and determine how oceans affect climate.

Technicians work on the TIMED satellite

"It's a mission to measure the oceans' interaction with climate change," said Fu.

Jason-1, the first in a series of ocean-mapping missions, is named after the mythological hero who led the Argonauts on the search for the Golden Fleece, which they found and returned. Jason symbolizes a hard-fought quest for a worthy goal and civilization's fascination with the ocean.

Riding to orbit with Jason-1 will be the Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics, or TIMED, spacecraft. The satellite was shipped to California last week and is awaiting its riding partner.

TIMED will help scientists study a relatively uncharted chunk of the Earth's atmosphere, a region about 40-110 miles (60-180 kilometers) up that bridges Earth's environment and space.

It hasn't been studied much because ground-based instruments can only observe a small portion of the region, it's too high for balloons and rockets move through it so fast they only provide a brief snapshot, according to John Wolff, the TIMED project manager.

"It has an impact on our weather," Wolff told CNN.com. "It could have some impact on the greenhouse effect."

The 1,294 pound (587 kilograms) TIMED probe was built at Johns Hopkins University's Applied Physics Laboratory in Laurel, Maryland. It measures about 9 feet (2.72 meters) long and 5 feet (1.61 meters) wide in the launch configuration. With its solar arrays, the probe is 38.5 feet wide.

"TIMED is going to explore one of the last frontiers in Earth's atmosphere," said Kristi Marren, a spokeswoman for Johns Hopkins.

The probe also will gather data on the effects of the sun and human activities on the region.

"Compared to other layers of our atmosphere, we know very little about this region, which is located just a few miles above our heads," says Sam Yee, a TIMED project scientist.

TIMED is the first mission in NASA's Solar Terrestrial Probes Program, part of the space agency's initiative to provide low cost access to space to study the sun-Earth system. The probe and its launch vehicle, a Delta II rocket, will cost about $189 million and the cost of managing the mission will run about $38.2 million, according to NASA.