The NASA High Altitude Student Payload (HASP) project provides a spot on a high altitude balloon payload for undergraduate and graduate students. When I heard about this last year, I gathered a team together, we applied and were accepted into the program. Our project: launch infrasound microphones into the stratosphere. Infrasound (sound at frequencies below audio range) is usually measured at the Earth’s surface, but we know it propagates hundreds of kilometers upward into the atmosphere. Our goal is to measure these sound waves as they cross the stratosphere.
The HASP project was definitely a commitment. As the team leader, I was required to write a monthly status report letting the HASP project leaders know what I was up to. I had to build my payload box under strict power draw, weight, and size limits. I also had to learn electronics from the ground up. Thankfully, another member of our team had lots of experience in electronics, so it wasn’t so bad.
A few weeks ago, I traveled to Palestine, Texas to bring my payload to the Columbia Scientific Balloon Facility (CSBF). There, our payload was subjected to extreme temperatures (ranging from -50 to 50 Celsius) and pressures (sea level to stratospheric). We passed the test, recording the 8 Hz signal from the vacuum pump clearly even when the pressure was around 5% of sea level. This was an important milestone: not only did it clear us for flight, but it also showed that our differential pressure microphones (constructed by Dr. Jeff Johnson at Boise State University) would operate in a near vacuum, something they were not designed to do.
From Texas, I traveled to New Mexico to launch our payload into the stratosphere. I ended up staying in my home town, about 2.5 hours from the launch site at (a CSBF facility in Ft. Sumner, NM). Needless to say, I spent a lot of time on the road! I had to drive there and back three times: once to put my microphones on the flight ladder (see below), another time to make sure everything worked during the “hang test” (a dry run for launch), and finally for the big day itself – the flight.
Like any balloon flight, this one depended on the weather. This time, the news was not good. One group was ahead of HASP, and they had dibs on each launch window. They tried twice, and were not able to fly both times. I had to fly home on Saturday, so I showed CSBF and HASP personnel how to set up my payload, and I resigned myself to not seeing the balloon fly.
But as luck would have it, the previous team decided to wait, and a launch window opened Saturday morning, the day I was scheduled to fly home. Since the flight was early in the morning and my plane ticket was for early afternoon, I decided I was going to go see the launch. I drove out, arrived in Ft. Sumner at about 10 PM, slept in the back of the car for a few hours, then got up at 2:45 AM Saturday morning to start getting ready.
The launch was touch and go the whole time – we had to wait for the winds to all blow in the same direction for the first 1000 ft in order to start the inflation process. As luck would have it, they did straighten out, and the call was given to roll out and start inflating the balloon.
The launch was spectacular. The balloon was released and drifted into the air. Big Bill started driving in the direction that the balloon was going, and just when it was overhead, the payload was released. The entire structure (800 ft high!) was now in free flight. It seemed to climb slowly, but that was an illusion – when the balloon was 12,000 ft above the ground it still seemed close enough to touch.
The balloon flew for about 8 hours, and was terminated over northeast Arizona. Once the recovery team picks it up and ships us our data logger, we can find out what we heard up there.
A big thanks to the Louisiana State team for running HASP, and all the great people at CSBF who made it all happen!