As the location for NASA’s long-duration, mid-latitude super pressure balloon missions, one might ask: Why Wanaka, New Zealand? Six reasons come to mind: latitude, attitude, solitude, duration, weather and night.
Some science experiments need to observe phenomena in the sky at locations only accessible by launching mid-latitude balloon flights centered around 45 degrees south latitude. Wanaka Airport, at 44 degrees 43 minutes south latitude, is a near perfect location for these missions. In addition, the galactic center of the Milky Way, which is the focus for many science investigations, is only visible in the southern hemisphere’s mid-latitudes.
The support from the local community and the airport staff make Wanaka an excellent place to launch. In addition, requirements for a launch location include access to a launch area such as a runway as well as access to heavy equipment, housing for staff, restaurants, support services, and more. While parts of New Zealand are remote, the easy access to all of these areas makes Wanaka an ideal place to launch.
From a flight safety perspective, it is much more desirable to fly over unpopulated areas. By launching into the southern hemisphere’s mid-latitudes from Wanaka, much of the balloon’s flight path is over water and the few potential land crossings are largely over sparsely populated areas.
The key to flying long duration is to launch into the southern hemisphere’s stratospheric winter cyclone, a weather phenomenon that develops in the fall characterized by easterly winds that produce a clockwise stratospheric airflow about Antarctica on up to mid-latitudes. Wanaka’s location enables launches into the stratospheric cyclone during this time of year.
Wanaka offers excellent weather conditions for NASA’s scientific balloon launches. Mornings are often characterized by light winds with a steady, uniform direction during this time of year allowing for more potential launch opportunities.
NASA’s other long-duration balloon flight launch locations, Antarctica and Sweden, are conducive for operations in constant daylight. However, some science missions require nighttime observations, often for extended periods of time. The predictable diurnal cycles (day/night cycles) make Wanaka ideal for instruments that need nighttime for observations.