Description of the payload

The instrument is a radio telescope to detect ultra-high energy cosmic-ray neutrinos from a scientific balloon flying over the continent of Antarctica. It will be the first NASA observatory for neutrinos of any kind.

Neutrinos are of great interest to astrophysicist as they are the only particle that can reach earth unattenuated at all energies. This is particularly of interest at high energies where other particles and photons will interact with the photons of the microwave background making them unable to propagate and survive over long astrophysical distances. In other words, if the scientists want to see the ultra-high energy universe, they should view it through the "light" of neutrinos.

The ANITA instrument detects these ultra-high energy neutrinos by use of the Askaryan effect. This effect predicts the production of a coherent radio emission from the cascade of particles produced in a high-energy particle interaction. In other words detecting a 'snap' in the radio frequencies caused by the interaction of the ultra-high energy neutrino.

In order to detect this radio emission (Askaryan pulses) it's needed a radio transparent medium for the interaction to occur in - and lots of it since these interactions are rare. Some materials that are radio transparent are salt, sand and ice. Also needs a fairly radio quiet area as the Askaryan pulses are very faint signals.

The ANITA instrument was designed to fly over the continent of Antarctica - the location of some of the most pure ice in the world as well as one of the most radio quiet spots on earth. Flying at 120,000 ft (~ 37 km) the instrument can observe ~1.5 million square kilometers of ice. However Neutrinos are so rare that with a detection area that large the scientists don't expect to see more than a hundred or so events.

Details of the balloon flight and scientific outcome

 

Launch site: Williams Field, McMurdo Station, Antarctica  
Balloon launched by: Columbia Scientific Balloon Facility (CSBF)
Balloon manufacturer/size/composition: Zero Pressure Balloon Raven - 39.000.000 cuft - (0.8 Mil)
Flight identification number: 590N

The balloon was launched by dynamic method at 10:17 am local time on December 21th and after 8 hours of initial climb it reached float altitude near 120.000 feet to succesfully ride over the polar vortex to start his first Antarctic turn. On January 20th, 2009, was initiated the termination process for the mission, sending the signal that separated the payload from the balloon, via the TDRSS satellite relay system directly from CSBF's Operations Control Center in Palestine, Texas. After a nominal descent under parachute, the instrument landed 122 nautic miles SW of the Siple Dome at 13:15 UTC that same day. It tipped over upon impact, but was in good condition as it continued to transmit data through the Iridium system. Total flight time was 30 days, 15 hours, and 58 minutes.

On January 27, a team from the ANITA mission was deployed to the Siple Dome Camp following plans made during the previous days to use that location as headquarters for the recovery operation. The next day the team was able to spend half the day working on dissasembling the payload and returned to Siple Dome with the data vaults, data computers, twenty antennas, CSBF's Support Instrument Package, and miscellaneous structural components. By Febraury 2 the recovered materials from ANITA where all stored at Siple Dome and two days after they were transported to McMurdo Station for final packing and return to United States.

External references and bibliographical sources

Images of the mission