SUPER-PRESSURE BALLOON TEST SN12

The NASA Super Pressure Balloon (SPB) is a large, sealed, high-altitude balloon engineered to maintain a constant positive internal pressure relative to the surrounding atmosphere. This positive pressure allows it to preserve a nearly constant volume, which in turn provides remarkable altitude stability, especially valuable during the day/night cycles encountered at mid-latitudes. This contrasts significantly with conventional zero-pressure (ZP) balloons, which experience considerable altitude variations due to thermal changes from solar exposure and night cooling.

The SPB is specifically designed to address this limitation, enabling extended-duration flights in regions where traditional ballooning has been constrained. The overall shape of the balloon is an oblate spheroid, meaning it resembles a slightly flattened sphere-squashed at the top and bottom-with the height measuring about 60% of its diameter. The structure of the balloon is composed of many individual vertical panels called gores. Each gore stretches from the top to the bottom of the balloon and has edges that are heat-sealed together. These sealed joints incorporate a strong, lightweight tendon or rope that also runs from top to bottom, contributing to the balloon's structural integrity. Under internal pressure, the gores form a slightly curved and lobed shape, resulting in the balloon taking on a characteristic "pumpkin" appearance when fully inflated. The balloon is filled with a precise amount of helium lifting gas, carefully calculated in relation to the payload mass to be carried and the target pressure altitude, which is approximately 33.5 kilometers (or roughly 110,000 feet). As the balloon ascends through the atmosphere, the decreasing ambient pressure allows the helium to expand within the sealed structure without compromising its form, thereby helping it to float at a predetermined altitude. The SPB serves as a platform for scientific missions that require long-duration, high-altitude observations that are impractical from polar regions or space, such as certain Earth science investigations and instrument development for future satellites. Its ability to maintain altitude with minimal fluctuation and its compatibility with mid-latitude flight paths greatly expand the potential for balloon-borne research missions.

The design and performance of the SPB are being validated through a series of incremental test flights. Currently, the SPB remains in its qualification phase, during which all payloads flown are considered "missions of opportunity". This designation implies that while these payloads can achieve valuable scientific objectives, they are secondary to the primary goal of testing the balloon's capabilities. Consequently, there is an inherent risk that payloads could be lost due to potential failures in the balloon system. Such missions are essential for advancing the SPB's development, as they provide real-world data on performance and reliability under various conditions. The insights gained from these flights are crucial for refining the technology and ensuring the success of future long-duration scientific missions.

THE PAYLOAD

Main objective of the flight was to further test the super pressure balloon technology and associated sub-systems. Aditionally, other five piggyback missions of opportunity were also included onboard as follows:

CoMIC or Compact Multichannel Imaging Camera, an experiment led by University of Massachusetts Lowell to study and measure how Earth's atmosphere scatters light at high altitudes. The instrument also will measure�airglow, specifically the red and green emissions.

HIGHS or High-altitude Infrasound from Geophysical Sources, an experiment developed by NASA's Jet Propulsion Laboratory and Sandia National Laboratories, that will measure atmospheric pressure to collect signals of geophysical events on Earth such as earthquakes and volcanic eruptions. These signals will help NASA as it develops the ability to measure seismic activity on Venus from high-altitude balloons.

MOANA the acronym for Measuring Ocean Acoustics North of Antarctica an experiment developed by Sandia National Laboratories and Swedish Institute of Space Physics, aimed to capture sound waves in Earth's stratosphere with frequencies below the limit of human hearing.

INDIGO or INterim Dynamics Instrumentation for Gondolas a system of sensors developed by NASA's Balloon Program Office, at Wallops Flight Facility to measure the shock of the gondola during the launch, termination, and landing phases of flight.

Finally SPARROW-7 which stands for Sensor Package for Attitude, Rotation, and Relative Observable Winds - 7 also developed by NASA's Balloon Program Office, a technological demonstrator for relative wind measurements using an ultrasonic device designed for the balloon float environment to obtain accurate data on wind speed and direction.

Balloon launched on: 5/4/2025 at 00:38 UTC
Launch site: Wanaka Airport, Otago, New Zealand  
Balloon launched by: Columbia Scientific Balloon Facility (CSBF)
Balloon manufacturer/size/composition: Super Pressure Balloon Aerostar - 18.793.000 cuft
Flight identification number: 751NT
End of flight (L for landing time, W for last contact, otherwise termination time): 5/13/2025
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 9 d 6 h 36 m
Landing site: 25 nautical miles NW of Estancia Los Alamos, Chubut, Argentina

• NASA Safely Ends Second Super Pressure Balloon Test Flight� NASA website
• Second NASA Super Pressure Balloon at Float NASA website
• Tufts Sonic Anemometer - Long Duration Balloon Mission 2025  
• Tufts-designed sonic anemometer will circumnavigate the globe via balloon Tufts University website