The U.S. has an active and healthy high-altitude balloon program that does a lot of cool science and technology development missions for the space industry. The NASA Balloon Program Office is managed by Goddard Space Flight Center out of the Wallops Flight Facility, but the Columbia Scientific Balloon Facility (CSBF) in Palestine, Texas is responsible for all of the services surrounding high-altitude balloon missions. The majority of U.S. missions are sponsored through grants by NASA and the National Science Foundation (NSF), although universities and companies in the industry also sometimes use balloon missions as opportunities for low-cost technology development. A unique aspect of balloon missions is that the payloads can almost always be recovered, which improves the likelihood of maximum data return and even allows us to refurbish the flight systems and instruments to use them again on future flights. How big are these balloons? These balloons are huge. Each long duration balloon (LDB) is capable of carrying payloads up to about 8000 lbs (~3600 kg) and can fly at altitudes up to 137,000 feet (~42 km), depending on the weight of the payload. When fully inflated, the balloon is 400 feet tall and 460 feet in diameter and looks like a giant pumpkin. To put it in perspective, a football field is 360 feet long and 160 feet wide So you could play football inside one of these balloons I guess! This is my favorite diagram from NASA that shows the size of the balloons they use. At launch (left) it is only partially inflated because once it gets high into the atmosphere there is so little air pressure that the balloon expands to its full giant size (right) even though it only started with a small amount of helium. Oh an the little black dot at the bottom that is labeled "Payload" - that represents our 22-foot tall gondola, which is tiny in comparison to the balloon itself. Image credit: NASA. Where do balloons launch from? Launch location depends on each mission’s science goals and how long you want to stay in the air. Most launches occur out of Fort Sumner, New Mexico or McMurdo Station in Antarctica, although there other launch sites around the world, including in Sweden, Alaska, and Australia. How long do balloons stay in the air? Typically flights out of Fort Sumner, NM can only stay afloat for about 8-30 hours due to airspace and population safety restrictions and wind currents. The BOPPS mission that I was a part of last year lasted for 17 hours before we had to cut it down, and that was considered very successful. You can see a map of the flight path that BOPPS took here. Flights out of McMurdo in Antarctica can stay afloat for several weeks since the Antarctic stratospheric wind currents make a slow loop around the continent, and there are no populated areas that cause safety concerns. Below are some flight paths that last year's Antarctic missions took. ANITA III on the left is an example of what most people want: one full revolution around the continent and the start of a second revolution, so a total of over 22 days in flight! SPIDER on the right also looks like it was probably a successful mission with 16.5 days of flight time and almost a full revolution. For the two missions in the middle, there could be any number of reasons why they were shorter, and I can only speculate as to what they were. More than likely something was not working correctly with their systems and they decided to end the mission early. How do they decide when to end a mission? There are many factors that go into deciding when to end a mission. If something is broken to the point where you cannot collect any good science data, there is no point in keeping the mission afloat. Flying balloons takes resources: people's time spent planning and commanding the systems, communication time and bandwidth with satellites to get the data back, and people's time spent waiting on the ground to go retrieve the hardware after it comes down. Many things can happen during flight, some expected and some unexpected. You can run out of cryogens that keep the instruments operating at the temperatures they need in order to work. You could run out of power if you only have batteries and no solar panels, A mechanism could get stuck or stop working leaving you with the inability to point or control some components. Occasionally the balloon itself will have a problem and will leak helium must faster than expected (but that is rare with these tried-and-true balloons). Eventually you will also run out of ballast, which is what we use to keep the balloon up at the desired altitude. So just like birthday balloons eventually get droopy, these balloons will eventually also start sinking back to the ground.
3 Comments
10/19/2015 07:53:33 am
A great description of the work you're doing. I especially like the title.
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Laura Kick
10/23/2015 10:23:24 am
This is awesome, Kate! I can't wait to hear about your adventures. Also, is there any remote change that you'll get to hug a penguin?
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10/26/2015 02:34:13 am
Kate, thank you for putting up this Blog, still on my Bucket list to get down there after supporting NASA up in Devon Island, always envious of the polies that bounce between the two every year, looking forward to tracking your progress. Cheers!
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