NLSI and LADEE Education and Public Outreach teams are developing a program of radio astronomy that will support LADEE science and enable amateur radio enthusiasts to participate in the mission. NASA’s partnership with the California School for the Blind and the National Federation for the Blind will enable participation by visually-impaired students across the Nation.
LADEE is scheduled to launch in 2013, go into lunar orbit, then drop down to low altitude to directly sample and measure the lunar atmosphere. Scientists believe that the lunar atmosphere has several major sources, one of them being meteoroid impacts on the lunar surface. By correlating changes in the rates of meteoroid impacts on the lunar surface with changes that LADEE’s instruments see in the structure and composition of the lunar atmosphere, researchers will gain a better understanding of the role of these impacts as a source for the Moon’s atmosphere. Since the Earth and the Moon travel together through space, encountering streams of debris together, observations of meteors in the Earth’s atmosphere can allow scientists to make inferences as to what is happening on the lunar surface.
While meteor counts from visual and video observations will provide useful data and a way for the general public to participate in the science of the mission, counts made by radio observers listening for reflection events provide some unique advantages. Specifically, radio counts will provide a greater degree of freedom from constraints imposed by weather and light pollution (both man-made and arising from fuller lunar phases). Radio observations also provide the best way to measure activity from those meteor showers that encounter the Earth during daylight hours. Thus, the amateur radio community has an opportunity to directly participate in the LADEE mission and contribute to real lunar science research.
Using radio methods is the only way to monitor meteor impacts during the daylight hours or on nights of cloudy weather. Meteors produce a column of ionized gas as they pass through the atmosphere. The columns of ionized gas created by meteors usually last for only a fraction of a second. Brighter meteors can produce columns that last for several seconds, often as visible persistent trains. These columns reflect radio waves from transmitters on Earth’s surface.
A radio meteor event will occur as a sudden fragment of a broadcast where there was no signal before. Radio observers monitor the activity in two ways: they manually count the number of events or reflections, or they use a computer to do the monitoring. Radio observations offer a particularly exciting opportunity to engage visually impaired students, but participating in meteor counts, either visual or radio-based, could be a great activity for students too and is something you can try at home.
Most radio systems are of the forward scatter type that can monitor radio waves on FM receivers. When using FM receivers at home, find an empty frequency in the low end of the FM band between 88 and 104 MHz. If you happen to have a multiband receiver then use the VHF band frequencies between 40 and 60 MHz. Channel 2, if not used in your area, is a particularly good frequency at 55.25-59.75 MHz. Free or low-cost software is available on line from Ilkka Yrjola and Christian Steyaert of the Radio Meteor Observers Bulletin (http://www.rmob.org/index.php).
While the concepts of radio observations and visually-impaired observers are quite exciting, the traditional visual count is a great tool for engaging the general public. This could be especially so when combined with the new Meteor Counter app released by the NASA Meteoroid Environment Office for the iPhone and iPad (http://meteorcounter.com/).
Here are a few additional online resources about radio detection of meteors:
How to Use Your FM Radio to Detect Meteors
NASA Meteoroid Environment Office – Forward Scatter Meteor RADAR
International Meteor Organization – Radio Observations Page
Radio Meteor Observing Bulletin
The International Project for Radio Meteor Observation
Spaceweather.com Radio Meteor Tutorial
Meteor Scatter Obs with VHF Radio & Computer
Posted by: Soderman/NLSI Staff