Cloud experiment launch scrubbed

NASA is experimenting with artificial clouds. A rocket experiment that may shed light on the highest clouds in the Earth's atmosphere was scheduled to launch from NASAs Wallops Flight Facility on the Eastern Shore Tuesday night but has been postponed due to weather.

The Experiment will be conducted by the Naval Research Laboratory and the Department of Defense Space Test Program using a NASA four-stage Black Brant XII suborbital sounding rocket.

Using ground based instruments and the STP/NRL STPSat-1 spacecraft, scientists will study an artificial noctilucent cloud formed by the exhaust particles of the rocket's fourth stage at about 173 miles altitude.

The rocket flight and the resulting cloud may be seen throughout the mid-Atlantic region. The artificial cloud also may be visible just before sunrise the morning after the launch.

Ground based cameras and radars will be based at various observation stations along the Atlantic coast and in Bermuda. Because of the optical observations, the launch will require clear skies not only at Wallops, but also at the multiple observation stations.

Special instruments will track the dust cloud for days, or even months. An instrument called the "SHIMMER" instrument has previously viewed natural noctilucent clouds for the past two years. The will be the first space viewing of an artificial noctilucent cloud.

Data collected during the experiment will provide insight into the formation, evolution, and properties of noctilucent clouds, which are typically observed naturally at high latitudes.

Natural noctilucent clouds, also known as polar mesospheric clouds, are found in the upper atmosphere as spectacular displays that are most easily seen just after sunset. The clouds are the highest clouds in Earths atmosphere, located in the mesosphere around 50 miles altitude.

They are normally too faint to be seen with the naked eye and are visible only when illuminated by sunlight from below the horizon while the Earths surface is in darkness.

A team from government agencies and universities, led by the Naval Research Laboratory, is conducting the experiment.

NASA says they will not launch any earlier than Friday, September 18.

The launch will be web cast, beginning one hour before the opening of the launch window at:
http://sites.wff.nasa.gov/webcast .

In addition, the launch status can be followed on Twitter at: http://twitter.com/NASA_Wallops .