A NASA
spacecraft aimed at probing the mysteries of Earth's highest clouds is gearing
up for launch.
The space
agency's Aeronomy of Ice in the Mesosphere (AIM) satellite is counting down towards
an April 25 space shot to begin the first-ever mission dedicated to tracking
Earth's odd noctilucent
- or 'night shining' - clouds.
First observed
in 1885, the clouds - also known as polar mesospheric clouds (PMC) - are made
of ice crystals hovering some 50 miles (80 kilometers) above Earth. They are only
visible at night when they reflect sunlight after the Sun has dipped below
the planet's horizon.
In recent
years, the previously rare clouds have been found to shine brighter, occur more
frequently and appear at lower latitudes than ever before, leading some
scientists to speculate that their behavior may be related to global climate
changes, such as global warming, said Vicki Elsbernd, NASA's AIM mission program
executive at the agency's Washington, D.C. headquarters, during a Wednesday
briefing.
Built for
NASA by Orbital Sciences and overseen by researchers at Hampton University in
Hampton, Virginia, the $140
million AIM spacecraft is slated to rocket spaceward at 4:26:49 p.m. EDT (2026:49
GMT) on April 25 atop an air-launched Pegasus XL rocket. About the size of a small
piano, the 430-pound (195-kilogram) spacecraft will depart from California's
Vandenberg Air Force Base on a two-year mission.
"Other
satellite missions have made measurements of these clouds, but they weren't
optimized and it was not their intent in the beginning," AIM principal
investigator Jim Russell, of Hampton University, told reporters Wednesday. "They
provided information, but not enough to really address the fundamental question
of why [the clouds] form and how they vary."
Because similar
cloud formations are seen high above the surface of Mars, researchers hope to
better understand their implications for life on Earth and future missions to
the red planet, Elsbernd added.
"We're very
excited about the AIM launch," Elsbernd said. "We expect that the new discoveries
from AIM, along with our other great observatory missions, will literally rewrite
the textbooks in our understanding of Sun and its effects on the Earth's atmosphere
and on the solar system."
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