http://www.msnbc.msn.com/id/48779492/ns/technology_and_science-space/
The launch of two probes into Earth's radiation belts was delayed again early Saturday, this time due to unacceptable weather conditions.
NASA's Radiation Belt Storm Probes were due to be sent into space from Cape Canaveral Air Force Station in Florida at 4:07 a.m. ET, but the weather remained stubbornly no-go due to a violation of launch rules for lightning and storm clouds.
Liftoff was postponed for at least 24 hours. Forecasters said the chances for acceptable weather appeared to be worsening, to 40 percent on Sunday morning. Tropical Storm Isaac is currently on a path to sweep south of the launch site late Sunday.
Saturday's delay came on top of a postponement on Friday that was due to an apparent malfunction with a tracking system for the mission's unmanned Atlas 5 rocket. The launch team spotted a frequency drift in the tracking beacon used by the Air Force's Eastern Range to monitor the rocket after liftoff. The problem was resolved on Friday.
The $686 million Radiation Belt Storm Probes mission is a two-year project to study the radiation environment around Earth in unprecedented detail. The twin spacecraft are designed to fly in formation to explore the Van Allen Belts of radiation that encircle the Earth.
The Van Allen Belts are two doughnut-shaped zones of radiation around Earth. They were first discovered in 1958 by scientist James A. Van Allen and his team using data from the first American satellite Explorer 1. The first belt stretches from the top of Earth's atmosphere out to about 4,000 miles (6,437 kilometers) above the planet. The second radiation belt extends from about 8,000 miles (12,874 kilometers) to more than 26,000 miles (41,842 kilometers) above Earth.
Scientists hope the Radiation Belt Storm Probes mission will help them solve the mystery of how the radiation is created and behaves inside the Van Allen Belts, as well as the regions' role in space weather events— such as strong solar flares from the sun — that can pose a danger to satellites and astronauts in orbit.
The two Radiation Belt Storm Probes are solar-powered and nearly identical. The octagon-shaped satellites are about 6 feet wide (1.8 meters) and just over 4 feet tall (1.3 meters). They each carry a set of five instrument suites to study Earth's radiation belts.
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