The Boeing Delta 2 rocket soars from its seaside launch pad carrying the Jason and TIMED spacecraft. Photo: U.S. Air Force

Two spacecraft that will use the unique vantage point of space to study our home planet were successfully launched into orbit Friday by the 100th Boeing Delta 2 rocket.

The two-stage rocket fitted with nine strap-on solid-fueled boosters lifted off minutes after sunrise from the Space Launch Complex-2 West pad at Vandenberg Air Force Base in California.

Although there were 18 minutes available to get the rocket airborne, officials targeted the precise time of 1507:35 GMT (10:07:35 a.m. EST; 7:07:35 a.m. PST) for the launch so one of the two cargoes -- the Jason 1 oceanography satellite -- would be placed into the optimum orbit.

The Jason 1 mission, a joint French/U.S. endeavor, will replace the aging TOPEX/Poseidon spacecraft to continue the long-term monitoring of ocean circulation and the impact on global climate changes. Jason and its 9-year old cousin will fly in formation for the next several months so scientists can synchronize the data from the new satellite to keep the records of ocean research consistent.

"Jason has the tough challenge of living up to TOPEX/Poseidon expectations and we have every reason to believe it will do so," said Ghassem Asrar, NASA's associate administrator for Earth Science.

"TOPEX, in less than a decade, has revolutionized our scientific understanding of the role of oceans in Earth's climate system and continues to surprise us with new discoveries and new understandings of how oceans work and how they contribute to the formation of weather and climate."

TOPEX and Jason 1 measure the ocean surface topography -- the small hills and valleys on the ocean surface that are crucial to studying global ocean circulation.

"The ocean is a driving engine for our climate," said Gary Kunstmann, Jason 1 project manager at NASA's Jet Propulsion Laboratory. "Our long-term understanding of the long-range effects of the ocean clearly has benefits to society."

Jason 1, built in France by Alcatel Space, is carrying the same types of instruments as TOPEX, just with newer technology and better accuracy.

Doing oceanography from space makes the research extraordinarily faster, scientists say. It took 10 years for last sea-going survey of ocean characteristics, according to Eric Lindstrom, NASA's oceanography program scientist. TOPEX and Jason 1 can provide a snapshot of global ocean circulation every 10 days.

Illustration of the Jason 1 mission to take ocean height measurements. Photo: CNES

Charles Yamarone, the deputy director of the Earth Science and Technology Directorate at JPL, says Jason 1 will do what TOPEX has done, but with more precision. "Jason 1 will provide not only the same measurements that TOPEX/Poseidon provided, but also some real-time products within three hours and we believe the accuracy of the measurements will improve."

TOPEX's accuracy of ocean height is about two inches; Jason's will be capable of one-inch resolution. The better accuracy is critical to ocean monitoring since the changes over time are very small.

By blasting off when it did, the Delta rocket delivered Jason 1 into an orbital perch close to TOPEX without getting too close. Over the next month, controllers will maneuver the new satellite into the exact orbital path of TOPEX, with Jason 1 following TOPEX by about 60 seconds, or 300 miles. In this formation, Jason 1 can observe the same spot of ocean as TOPEX, allowing scientists to calibrate its data to match that of the TOPEX record, keeping the information consistent for long-term research. The long-term data collection is needed to understand how the oceans and global climate change.

After six months of calibration, TOPEX will be moved to a parallel orbit, allowing Jason 1 to fly on its own for a planned three-year mission.

With Jason released from the Delta 2 rocket about 55 minutes after launch Friday, the Dual Payload Attach Fitting -- a barrel structure that encloses one satellite while allowing another to be bolted on top -- was ejected to exposed TIMED.

An artist's concept shows the Jason 1 spacecraft mounted atop the Dual Payload Attach Fitting structure. TIMED is enclosed within the barrel. Photo: CNES

At T+plus two hours and five minutes, the Johns Hopkins University-built Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics satellite, or TIMED for short, was deployed for its two-year mission to study the upper-most portions of Earth's atmosphere. The mission is the first in a series of "Solar Terrestrial Probes" designed to study the connection between the Sun and Earth.

"TIMED studies the outermost region of the Earth's atmosphere, the interface of the Earth's atmosphere and space," explained George Withbroe, the division director of NASA's Sun-Earth Connection program. "The purpose of TIMED is very simple: to fill in a large gap in our knowledge about the Earth's atmosphere and how it connects with the sun."

TIMED aims to study the least explored region of Earth's atmosphere -- the Mesosphere and Lower Thermosphere/Ionosphere, or MLTI. The area extends from 40 to 110 miles above the planet.

The region has been virtually impossible for scientists to study because it's too high for most airplanes and balloons, yet too low for satellites to fly through and probe.

With recent advancements in remote sensing technologies, TIMED will be able to orbit 388 miles above the planet and use its four instruments to remotely measure the basic structure, composition, temperatures and wind patterns in that region of the atmosphere, as well as the solar ultraviolet irradiance and emitted infrared light.

An artist's concept of the TIMED saatellite deployed in space. Photo: JHU/APL

"I think it is extraordinary that we know so little about this region of space which is so close to us. It is something that we have needed to do for a very long time in order to understand the whole system. This region is 60 miles above our heads, and we don't know what's there and we don't know what makes it work," said Mary Mellott, the TIMED program scientist. "We will know very much more once TIMED is flown and we've time to understand what it is telling us."

"TIMED will provide a very important benchmark for future studies of both natural and human-induced changes to the Earth's atmosphere," said Sam Yee, the TIMED project scientist. "TIMED's measurements will help scientists understand how the region's composition is affected by contaminants that are released into Earth's atmosphere and by solar energy entering this region."

Friday's launch marked the 100th flight for the venerable Delta 2 rocket. The medium-lift vehicle debuted on February 14, 1989 when it launched a NAVSTAR Global Positioning System military navigation satellite. Since then, the vehicle has completed a total of 98 successful flights.

The users of Delta 2 have varied between government and commercial customers.

On the government side, some 38 missions were flown for the U.S. military, including 35 GPS launches; 23 missions were performed for NASA to deploy various science spacecraft including five Mars probes; and one flight was dedicated to the U.S. National Reconnaissance Office, the government agency that operates the country's spy satellite fleet.

Delta 2 has flown 38 purely commercial flights, including 11 to deploy Iridium satellite telephone satellites and 7 for the rival Globalstar network.

To date, 80 of the Delta 2 launches have occurred from Cape Canaveral Air Force Station in Florida and the other 20 from Vandenberg Air Force Base in California.

The moon was in view as the Delta 2 rocket streaked to orbit Friday. Photo: Thom Baur/Boeing

This was the seventh and final Delta mission in 2001. The next launch is planned for February 8 when a Delta 2 will carry replacement satellites into orbit for the Iridium telephone network from Vandenberg.

The next NASA mission using the Delta 2 is planned for March 24 with the launch of the Earth observing probe called Aqua.

"We're basking in the glory of this success as well as looking to the future to see what's next," Chuck Dovale, NASA launch manager, said after Friday's mission.