A leak in a stadium-sized scientific balloon forced NASA flight controllers to bring it down in the South Pacific Ocean on May 6th. The super-pressure balloon (SPB) and its space observatory payload, worth several million dollars, have sunk to the bottom of the Pacific, about 321km south of Easter Island, with no chance of recovery.
Photo: NASA/Bill Rodman
Launched on 25th April from Wanaka Airport, New Zealand, the 18.8-million-cubic-foot (532,000-cubic-meter) balloon was carrying 5,500 pounds (2,495 kilograms) of equipment — the International Extreme Universe Space Observatory (EUSO-SPB) payload. It was expected to stay aloft in the stratosphere for 100 days to test the SPB technology and detect ultra-high energy cosmic rays from beyond our galaxy as they penetrate the Earth’s atmosphere.
The balloon was designed to float at a stable altitude of about 33.2 km (109,000 feet) for long durations despite the heating and cooling of the day/night cycle, but a leak in the balloon was confirmed on the third day of flight. The aircraft started experiencing significant altitude drops at night when the temperature dropped, regaining its predicted altitude during the day as the temperature rose.
Flight controllers at NASA’s Columbia Scientific Balloon Facility in Palestine, Texas, conducted a controlled flight termination of the balloon, on the 12th day of flight, causing it to descend from suborbital space, in three-and-a-half hours, before splashing it in the ocean.
To manage altitude loss, flight controllers had dropped ballast during cold storms, which can see atmospheric temperatures at -50 degrees and below. In the 11th day of flight, the team was left with just 74 pounds of ballast, and the balloon was still 2,000 miles away from South America.
Facing a poor weather forecast that would lead to even lower altitudes with little ballast remaining, NASA preemptively ended the flight to ensure the greatest level of control and safety during descent.
“It’s unfortunate that our flight has come to an end at this point—our goal was at least two weeks and our hope was for many more weeks beyond that,” said Debbie Fairbrother, NASA’s Balloon Program Office chief. “We were able to collect a great amount of flight data, however, which we’ll analyze in the coming weeks and months to see if we can determine a cause for the leak. We’ll apply lessons learned to future flights as we continue to develop this technology.”
“Our flight was cut short, but we are confident that the super-pressure balloon approach to observing the most energetic cosmic particles will pioneer a new understanding of these extreme phenomena,” said Angela V. Olinto, professor at the University of Chicago and principal investigator (PI) of the project. “The international EUSO Collaboration is deeply thankful for the support, expertise, and dedication of NASA to this historic opportunity to open a new window onto the universe.”
“EUSO-SPB performed well, and more than 60 GB of data was downloaded to ground,” said, Lawrence Wiencke, professor at the Colorado School of Mines and deputy PI for the EUSO-SPB flight. “We are looking forward to analyzing the data and to another super-pressure balloon flight with NASA.”
Astrophysicists did not receive any communication from the balloon and the payload after it impacted the ocean.
NASA conducted an environmental analysis of an open-ocean landing before beginning its mid-latitude SPB flight program in 2015. The open-ocean flight termination procedure makes use of the two-ton flight payload as an anchor to pull the entire balloon flight train to the bottom of the ocean as quickly as possible. In this way, the balloon does not remain in the primary water column zone where most marine species are known to live, minimizing environmental impacts.
NASA’s Wallops Flight Facility in Virginia manages the agency’s scientific balloon flight program with 10 to 15 flights each year from launch sites worldwide. Orbital ATK, which operates NASA’s Columbia Scientific Balloon Facility in Palestine, Texas, provides mission planning, engineering services and field operations for NASA’s scientific balloon program. The CSBF team has launched more than 1,700 scientific balloons in the past 35 years of operation.
Adapted in part by Sitara Maruf Source: NASA
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