"Just like for Earth's weather where there are numerous satellites covering the whole globe and studying different things, space weather needs to be studied on a much bigger scale," says Swarthmore College physicist Michael Brown. "You need to look at the sun and the Earth and all of the vast distance in between, so there needs to be lots of satellites and instruments."
Although the $216 million Genesis mission has unique features, Brown's comment is good news for NASA. There already are a number of solar-observing satellites in operation -- most notably the SOHO satellite, designed to study the internal structure of the sun, its outer atmosphere and the origin of the solar wind.
Other solar missions include NASA's TRACE satellite, which studies the sun at a high resolution but cannot see it all at once, as SOHO can.
Also, the International Solar Terrestrial Physics project is an umbrella for 12 different solar-observing satellites. NASA's Ulysses studies the poles of the sun and the solar wind.
From past data, scientists can infer the solar wind's composition, but Genesis will be the first to measure it directly, returning its samples to Earth for analysis. The plan is to measure the abundance of various forms of hydrogen, helium, oxygen and other gases emitted by the sun in hopes of learning about the building blocks of meteors, comets and our solar system.
"The other satellites rely on spectrometers and particle measurements. They are in situ (in position)," says Genesis mission director Chet Sasaki. "We are a sample return mission."
A potato chip trip
After a January 2001 launch, the Genesis spacecraft will journey a million miles sunward -- but only 1 percent of the distance to the sun .
Its path will follow a contorted set of loops, a potato chip-shaped trajectory used by some other solar observing satellites. It eventually will orbit a gravitational balance point between the sun and the Earth before unfolding silicon collectors, where particles will imbed themselves.
After two years of sunbathing, Genesis should return to Earth in 2003. A capsule with the collectors is slated to be rescued by a helicopter from a parafoil plummet over the Utah desert.
Sampling the sun
Most scientists believe the solar system was formed 4.6 billion years ago by the gravitational collapse of the solar nebula, a cloud of interstellar gas, dust and ice created from previous generations of stars.
As time went on most of the gas and dust was pulled together by gravity to form the sun while other grains of ice and dust stuck to one another, eventually forming planets, moons, comets, and asteroids.
By examining the makeup of the solar wind, scientists hope to learn the composition of the solar nebula. The sun itself is too hot to sample at its surface -- more than 3,000 degrees Fahrenheit.
And while it is possible we'll see more lunar landings and lunar samples in coming years, the Genesis mission is designed to make it so no one ever has to sample the sun again, let alone consider the impossible -- landing there.
"This is the periodic table of NASA missions because we are looking at the sun's chemistry for all the missions," says Genesis public outreach director Alice Krueger. "Ours is a terribly basic mission."
Launch of crucial weather satellite postponed
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