TIGER -- Trans-Iron Galactic Element Recorder -- lifted off from McMurdo Station in Antarctica at 5:30 a.m. CST Dec. 20, suspended from a pilotless helium-filled balloon. After traveling approximately 9,000 miles around the perimeter of Antarctica, the experiment landed 31 days, 21.5 hours later -- at 2:55 a.m. CST Jan. 21, some 284 miles from its launch site.

TIGER, short for Trans-Iron Galactic Element Recorder, is hoisted onto the launch vehicle for pre-flight testing at McMurdo Station in Antarctica before its record-breaking flight.

The previous endurance record for a long-duration scientific balloon flight was set in January 2001, also from McMurdo Station. That flight was one orbit of the South Pole, lasting 26 days. The TIGER mission more than doubled the amount of continuous science observational time over any previous balloon mission.

The instrument, designed and built mostly by faculty, staff and students in the cosmic ray astrophysics group in the McDonnell Center for the Space Sciences and the Department of Physics in Arts & Sciences, traveled some 125,000 feet into the atmosphere to measure the elemental abundances of galactic cosmic rays (GCRs).

Researchers from NASA's Goddard Space Flight Center, Greenbelt, Md.; California Institute of Technology, Pasadena; and the University of Minnesota, Minneapolis, also are collaborating on TIGER.

"The importance of TIGER is that it is the first experiment that has both sufficient collecting power and adequate resolution to measure abundances of all nuclei from iron through zirconium," said W. Robert Binns, Ph.D., research professor of physics, who is principal investigator on the project and was in Antarctica for almost two months. "This will enable us to determine whether the cosmic-ray source is hot or cold, gas or solid. We have already seen in our quick-look analysis of flight data that TIGER's resolution is sufficient to resolve those nuclei."

The study of GCRs will lead to a better understanding of their origin and the explosive processes in our galaxy that are responsible for giving the nuclei such enormous energy.

A field team reached the instrument and recovered the on-board hard disk with the complete recording of all the data. John Epstein, director of engineering development for Washington University's cosmic ray group who had been in Antarctica since the beginning of December, helped disassemble the 1.5-ton instrument to return it to McMurdo Station for shipping back home.

Epstein reported that a preliminary look at the instrument shows that it sustained some damage during the landing, but that the damage didn't appear to be too serious.

According to Martin H. Israel, Ph.D., professor of physics and a co-investigator on TIGER, "We are hopeful that with some repairs and refurbishment, TIGER will be ready to fly again two years from now."

Jason Link, a physics graduate student whose doctoral thesis will be based on this mission, is relieved that TIGER did what it was supposed to do.

"We had complete recovery of our primary data through the Tracking and Data Relay Satellite System, and preliminary analysis of the data we received demonstrates that the instrument was working beautifully throughout the flight," said Link, who has worked on the mission for four years and spent the past two months in Antarctica.

Israel added, "We expect to have results on the detailed composition of the cosmic rays with atomic numbers between 26 and 40 by about this time next year."

To complete the flight, the experiment and its parachute floated to the ground after being separated from the balloon by radio command. Helium was released from the balloon for its descent.

Personnel from NASA's National Scientific Balloon Facility conducted TIGER's launch, flight and recovery operations. The McMurdo Station is operated as part of the National Science Foundation's Antarctic Program.

Joining Binns, Epstein and Link in Antarctica from Washington University were Paul Dowkontt, electrical engineer; Garry Simburger, electrical technician; Dana Braun, mechanical technician; and Lauren Scott, a physics graduate student.