From the study of the atmosphere to the origins of the universe, the unmanned scientific balloon has been the vehicle for some important scientific discoveries and holds more promise for significant investigations in the future. Described as the quiet workhorse of space science—the scientific balloon is the quickest and cost-efficient way to carry heavy payloads and experiments to near space—more than 100,000 feet above the Earth’s surface.
The NASA Balloon Program was established 30 years ago for scientific and technological investigations and to contribute to our understanding of the Earth, the solar system, and the universe. According to NASA experts, satellite missions take five to seven years to develop and they cost millions of dollars, while scientific ballooning can be done at a fraction of the cost. From New Mexico to Arctic Sweden and Australia to the coldest and driest continent Antarctica, NASA’s Columbia Scientific Balloon Facility launches 15 to 20 balloons a year for any science that can be done above 99.5% of the atmosphere, either above or below the floating balloons.
A standard NASA scientific balloon is constructed of a polyethylene film that is only 0.002 centimeters thick, about the same as an ordinary sandwich wrap. The film is cut into banana-peel shaped sections called gores and heat sealed together to form the balloon. The total length of seals in one balloon can run 20 miles (32 km). More than 200 gores are used to make NASA’s large balloons, each requiring about 20 acres of material.
These giant balloons can fly 8,000 pounds of payload (scientific equipment), equivalent to the weight of three small cars, nearly 26 miles high and can float in near space for weeks. Flying above 99.5% percent of the Earth’s atmosphere gives clear and excellent views of space without any interference from the atmosphere.
The balloon platform has yielded some world-class science discoveries. In the mid 1980s, initial measurements made from scientific balloons led to the discovery of an ozone hole over the Antarctic continent. Another significant balloon-borne experiment called “Boomerang,” in 1998, showed findings that the geometry of the universe is flat and it’s continually expanding, and in 2003 a cosmic ray experiment called CREAM, launched on a long-duration scientific balloon, orbited the South Pole three times, setting a record of 42 days at float. Among other research projects, balloon payloads have been used to study the origins of the universe, cosmic rays, supernova, black holes, dark energy, dark matter, and other space phenomena.
The era of balloon science was launched on the day the first balloon took off in 1783 in France and continues to this day. In the past, a lot of the science and space research involving balloons needed daring humans to fly to higher altitudes and into near space. Various explorers soared in balloons to observe weather phenomena, test instruments and gear, and experience the effects of the dangerous near-space environment on human physiology. Some even lost their lives in their effort to contribute to our knowledge of science, medicine, space, and travel.
Over the decades, advances in research, technology, and ballooning paved the way to explorations without risking any human life. Though these are unmanned missions, launching a scientific balloon with its heavy payload requires tremendous preparations, safety procedures, and the correct combination of weather at various altitudes. Inappropriate weather can cause delays for as long as two weeks. Each launch may be slightly different based on the experiments involved; however, the main procedure of a scientific balloon flight is same. Prelaunch involves a complex hands-on rigging process. A specially designed launch vehicle is used to launch the balloon with its heavy payload.
For a successful launch, winds cannot exceed six to seven miles per hour in the first two hundred vertical feet; from 200 to 1000 feet, winds must be less than 12 miles an hour; and, from top to bottom, winds must be in a constant direction. Any shift in wind speeds during inflation can shred a balloon, so the crew tests for surface wind speeds using small tethered pilot balloons. To launch, the balloon is partially filled with helium and, as it rises, it expands to a volume of up to 40 million cubic feet (NASA’s largest balloon is 60 million cubic feet), nearly the size of a stadium. These zero-pressure balloons are open to the atmosphere at the bottom to equalize the internal pressure with the surroundings. The balloon system includes the balloon, the parachute and a payload that holds instruments to conduct scientific measurements.
After about two hours of ascent, balloon and payload reach near space. As precious data is gathered for days or even up to weeks, the team monitors the balloon in real-time with sophisticated software. The crew is required to keep a chase aircraft within one hour of flying time from the balloon.
If all goes according to plan, the flight can be concluded at a predetermined time and the aircrew gets clearance from the FAA to terminate the flight or separate the payload and the balloon. After surveying the projected landing point, a telemetry command fires an explosive squib that separates parachute and balloon around 120,000 feet. This separation tears the balloon, and the payload descends by parachute in about 50 minutes. The circling aircraft monitors the descent of the balloon and the payload. As the payload touches the ground, flying sensors send a signal which leads to the next step of firing explosives that separate the parachute from the payload to keep it from dragging in strong wind situations. In the end the payload is recovered and returned to the science team to fly another day.
NASA claims that in over 2,200 scientific balloon flights, there has never been a single injury to a crew member or anyone else. Since balloon payloads are capable of observations and measurements in natural environments and at various altitudes, NASA and other private enterprises are looking into the possibility of flying scientific balloons on other planets and space bodies, particularly Mars, Venus, and Titan. Such “in situ” measurements are currently not feasible with other platforms such as satellites and rovers. Even in this age of the space shuttle, the International Space Station, and rocketry, scientific ballooning remains an ideal and economical platform to learn about earth and space science.