A rocket experiment set to launch Tuesday aims to create
artificial clouds at the outermost layers of Earth's atmosphere.
The project, called the Charged Aerosol Release Experiment
(CARE), plans to trigger cloud formation around the rocket's exhaust particles.
The clouds are intended to simulate naturally-occurring phenomena called noctilucent
clouds, which are the highest clouds in the atmosphere.
"This is really essentially at the boundary
of space," said Wayne Scales, a scientist at Virginia Tech who will
use computer models to study the physics of the artificial dust cloud as it's
released. "Nothing like this has been done before and that's why
everybody's really excited about it."
The experiment is the first attempt to create artificial
noctilucent clouds. A previous
spacecraft, called Aeronomy of Ice in the Mesosphere (AIM), launched in
2007 to observe the natural clouds from space.
CARE is slated to launch Tuesday between 7:30 and 7:57 p.m.
EDT (2330 and 2357 GMT) from NASA's Wallops Flight Facility in Virginia.
Noctilucent means "night
shining" in Latin. Although difficult to spot with the naked eye, the
clouds are best
visible when Earth's surface is in darkness and sunlight from below the
horizon illuminates the high-altitude clouds.
These clouds, also known as polar mesospheric clouds, are
made of ice crystals. The natural ones tend to hover around 50 to 55 miles (80
to 90 km) above the Earth. CARE will release its dust particles a bit higher
than that, then let them settle back down to a lower altitude.
"What the CARE experiment hopes to do is to create an
artificial dust layer," Scales told SPACE.com. "Hopefully it's a
creation in a controlled sense, which will allow scientists to study different
aspects of it, the turbulence generated on the inside, the distribution of dust
particles and such."
CARE is a project of the Naval Research Laboratory and the
Department of Defense Space Test Program. The spacecraft will launch aboard a NASA
four-stage Black Brant XII suborbital sounding rocket.
Scientists will study its progress from ground based
instruments as well as the STP/NRL STPSat-1 spacecraft in Earth orbit.
Researchers will track the CARE dust cloud for days or even months to study its
behavior and development over time.
Because the optical observations are crucial, the launch can
only take place if the weather is clear both at the launch site and at multiple
observation stations along the Atlantic coast and in Bermuda.
If CARE cannot launch Tuesday, the team can try again
between Sept. 16 and Sept. 20.
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