Long-duration balloon flight

TIGER instrument 2001-2002

    TIGER instrument was launched from Williams Field in Antarctica which is about 6 miles northeast of McMurdo Station (lat. -77.86° S) on December 21, 2001 at 12:30 AM.  Antarctica is a particularly good place from which to launch such a balloon for several reasons.  The fact that the sun never sets during the Austral summer means that the balloon will undergo comparatively minor diurnal heating and cooling.  Furthermore, the winds set up in a circumpolar pattern which allows the balloon payload to maintain somewhat of a predictable trajectory over the continent.  Since Antarctica is virtually totally uninhabited, it is easy to avoid the concern involved with flying a uncontrolled balloon payload.   Finally, TIGER can collect more data below a geomagnetic cutoff of about 1 GV, which is possible only near the Earth's poles.
    The balloon circumnavigated the continent twice during its 31.8-day flight at an average altitude of 117,365 feet.  The first orbit of the continent lasted a total of 13 days and 21.4 hours while the second orbit lasted 17 days and 23.1 hours.  The balloon was a 29-million cubic foot scientific balloon launched by NASA's National Scientific Balloon Facility (NSBF).  It was made of a polyethylene film that is .02 mm thick.  When fully inflated, this balloon has a diameter greater than 300 feet.

Taken from excerpts of Jason Link's doctoral thesis

altitude plot

    This plot shows the balloon altitude over the course of the entire flight.  The constant dips in altitude are due to diurnal heating and cooling.  The plot shows that the balloon was constantly leaking during the flight.  Sudden increases in altitude such as that seen near day 12 were caused by the dropping of ballast.


latitude plot

    This plot shows the latitude of the balloon during its flight.  It is interesting to note that it deviated very little from its initial latitude during the first orbit, while during the second orbit, when the circumpolar winds were beginning to fade, it began to venture further southward.




    A bird's-eye view of the balloon flight.