MAXIS (MeV Auroral X-ray Imaging and Spectroscopy)

The scientific purpose for the MAXIS flight is to study electron precipitation from the magnetosphere into the ionosphere. This electron precipitation creates the aurora (northern and southern lights) along with X-rays.

The composite instrument consist of a bismuth germanate (BGO) X-ray spectrometer and two X-ray imaging cameras. One camera has a pinhole collimator and the other has a coded aperture mask collimator. Both cameras use scintillating crystals and photomultiplier tubes to detect X-rays which are produced in the aurora.

Also, the Berkeley balloon group provided a high resolution germanium X-ray spectrometer, nad NASA's Marshall Space Flight Center provided a radiation shielding experiment as a piggy-back cargo on this flight.

This experiment was originally scheduled for launch in June of 1999 from Fort Wainwright, Fairbanks, Alaska. However, the Alaska launch was cancelled and rescheduled for Antarctica.

During the mission, the auroral x-ray instruments on MAXIS recorded an event between 21:20 UT January 19 and 00:20 UT January 20. Also, an auroral x-ray event possibly associated with a shock in the solar wind was observed between January 22-26, 2000.

Balloon launched on: 1/11/2000 at 23:55 utc
Launch site: Williams Field, McMurdo Station, Antarctica  
Balloon launched by: National Scientific Balloon Facility (NSBF)
Balloon manufacturer/size/composition: Zero Pressure Balloon 800.000 m3 - SF3-29.47-.8/.8/.8-NA
Balloon serial number: W29.47-2X-43
Flight identification number: 478N
End of flight (L for landing time, W for last contact, otherwise termination time): 1/30/2000 at 21:13 utc
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 18 d
Landing site: 390 miles NW from McMurdo Station, Antarctica
Payload weight: 2314 lbs
Overall weight: 3875 lbs

After more than three weeks of weather related delays, on January 12, 2000 the balloon was launched from Williams Field by dynamic method.

After 18 days and a successfully circumnavigation of the South Pole at altitudes of about 120,000 feet, the flight was terminated on January 30, 2000 at 22:13 UT.

The balloon was cut-down over Victoria Land, approximately 390 nautical miles from McMurdo Station.

On February 3, 2000 the recovery team reached the payload via Twin Otter and found the gondola in relatively good condition considering it had come to a stop upside down following landing. The data vault containing the hard drive, the x-ray imagers, the BGO detector, and three of the four sun-sensor arrays were among the components successfully recovered.

• MAXIS website at University of Washington
• MAXIS website Dept. of Earth and Space Sciences - Washington University