The next launch using the Big 60 was flight 685NT from Fort Sumner, NM on
August 17, 2018. This flew for a total of 8 hours and reached an altitude of 48.5 km
(159,000 ft). One of the additional experiments was an advanced spherical steerable antenna system developed by FreeFall Aerospace of Tucson, AZ, in partnership with the University of Arizona. It was located in the left side of the gondola
in a specially added frame, while in a similar structure in the right side was a parabolic antenna also built by FreeFall Aerospace. The other experiment was the
CHERP (CHErenkov Radiator Payload) supplied by Gannon University in Erie,
PA. This was a cosmic ray instrument to detect high-energy particles of astrophysical origin in the energy range from 1.5 to 20 giga-electron-volt using two
Cherenkov radiation detectors.
A second test, flight number 687NT was also launched using the same dynamic
method on August 25, 2018. After a slow ascent lasting over 4 hours, the Big 60
reached a float altitude above 47 km (155,000 ft). During the ascent the balloon
moved initially to the northeast, but later on acquired a more or less stable flight
path to the west with a slight deviation north that would be unaltered during the
remainder of the flight. During the flight the balloon experienced some drops of
altitude that could be have been related to the presence of a very cold storm front
in the area. It flew for 9 hours 40 minutes.
The Big 60 is NASA’s largest zero-pressure balloon to date. If the polyethylene
material were to be spread out on the ground it would cover about 20 acres. The
larger size enables the balloon to float about 8 km (26,250 ft) higher than other
zero-pressure balloons; equivalent to about 20 Empire State Buildings closer to
the edge of space than NASA’s next largest balloon.
In addition to its larger size, the Big 60 is also half as thick as the other balloons
that NASA flies. At 10.2 μm (0.40157 mil) the plastic film covering the balloon is
a little less than the thickness of kitchen plastic wrap. These films go through three
stages of testing before they are flight ready, including quality control tests at the
Balloon Research and Development Lab of the Wallops Flight Facility. In the
stratosphere where the balloon floats, the temperature is typically –76°F, but the
films are rated to withstand –130°F in the lab.
The Big 60 uses the CSBF designed gondola, which has support instrumentation such as tracking, video and telemetry, together with tertiary experiments flying to round out the 748 kg (1,650 lb) suspended payload. The test flights evaluated
the Big 60’s overall design and ability to conduct science missions. Future tests
will go a step further and allow researchers to test new instruments.
In addition to providing unprecedented altitudes for scientific observations, the
UHAB also opened new avenues for long duration ballooning at mid-latitudes.
With altitude excursions of only 10-12 km (6-7 mi), these balloons are able to
execute long duration flights without the need for large quantities of ballast. If
augmented by a small super-pressure anchor balloon, altitude excursions can be
minimized. While not as capable as the ULDB for carrying heavy payloads, the
2.2 Zero-Pressure Balloons (ZPB) 15
August 17, 2018. This flew for a total of 8 hours and reached an altitude of 48.5 km
(159,000 ft). One of the additional experiments was an advanced spherical steerable antenna system developed by FreeFall Aerospace of Tucson, AZ, in partnership with the University of Arizona. It was located in the left side of the gondola
in a specially added frame, while in a similar structure in the right side was a parabolic antenna also built by FreeFall Aerospace. The other experiment was the
CHERP (CHErenkov Radiator Payload) supplied by Gannon University in Erie,
PA. This was a cosmic ray instrument to detect high-energy particles of astrophysical origin in the energy range from 1.5 to 20 giga-electron-volt using two
Cherenkov radiation detectors.
A second test, flight number 687NT was also launched using the same dynamic
method on August 25, 2018. After a slow ascent lasting over 4 hours, the Big 60
reached a float altitude above 47 km (155,000 ft). During the ascent the balloon
moved initially to the northeast, but later on acquired a more or less stable flight
path to the west with a slight deviation north that would be unaltered during the
remainder of the flight. During the flight the balloon experienced some drops of
altitude that could be have been related to the presence of a very cold storm front
in the area. It flew for 9 hours 40 minutes.
The Big 60 is NASA’s largest zero-pressure balloon to date. If the polyethylene
material were to be spread out on the ground it would cover about 20 acres. The
larger size enables the balloon to float about 8 km (26,250 ft) higher than other
zero-pressure balloons; equivalent to about 20 Empire State Buildings closer to
the edge of space than NASA’s next largest balloon.
In addition to its larger size, the Big 60 is also half as thick as the other balloons
that NASA flies. At 10.2 μm (0.40157 mil) the plastic film covering the balloon is
a little less than the thickness of kitchen plastic wrap. These films go through three
stages of testing before they are flight ready, including quality control tests at the
Balloon Research and Development Lab of the Wallops Flight Facility. In the
stratosphere where the balloon floats, the temperature is typically –76°F, but the
films are rated to withstand –130°F in the lab.
The Big 60 uses the CSBF designed gondola, which has support instrumentation such as tracking, video and telemetry, together with tertiary experiments flying to round out the 748 kg (1,650 lb) suspended payload. The test flights evaluated
the Big 60’s overall design and ability to conduct science missions. Future tests
will go a step further and allow researchers to test new instruments.
In addition to providing unprecedented altitudes for scientific observations, the
UHAB also opened new avenues for long duration ballooning at mid-latitudes.
With altitude excursions of only 10-12 km (6-7 mi), these balloons are able to
execute long duration flights without the need for large quantities of ballast. If
augmented by a small super-pressure anchor balloon, altitude excursions can be
minimized. While not as capable as the ULDB for carrying heavy payloads, the
2.2 Zero-Pressure Balloons (ZPB) 15