The space agency set off the twin robotic spacecraft, known as Solar Terrestrial Relations Observatories (or Stereo), from a Boeing Delta II rocket at Cape Canaveral Air Force Station, Fla., late Wednesday.
Nearly 90 minutes after launch, the two spacecraft split off and began their respective paths into orbit--one will swing around the moon to a position trailing behind the Earth, the other just ahead of it. The duo will map the structure of the sun and study the general environment in space.
"NASA's Stereo mission got off to a spectacular start as the rocket carrying the twin satellites blazed through the starry sky after lifting off," NASA announced on its Web site.
The $520 million project is the next frontier for scientists observing the sun and coronal mass ejections (CMEs), which are powerful solar eruptions that can disrupt the protective magnetic field surrounding Earth. Related to solar flares (scientists still don't know which come first), CMEs can travel at nearly 1 million miles per hour and "can pack the force of a billion megaton nuclear bombs," NASA says.
Scientists expect that with more understanding of CMEs they can better forecast weather in space and mitigate the problems posed for satellite operations, polar aviation, communication systems, power grids and astronauts in space. Radiation from the eruptions can harm orbiting astronauts, for example.
The mission will also prove beneficial for understanding the sun and its essential relationship to Earth, scientists say.
NASA's Stereo mission was initially expected to launch last December, but it had been delayed several times because of rocket technology recalls and a Boeing employee strike earlier this year.
Each robotic craft is roughly the size of a golf cart, but when the solar arrays are extended in space they expand to the size of a soccer net. Each craft carries 16 instruments that were developed in labs around the world and assembled at Johns Hopkins Applied Physics Lab.
After about 90 days in space, the craft will begin taking observations. A beacon on each spacecraft transmits data to the National Oceanic & Atmospheric Administration.