As part of the Global Space Balloon Challenge, and in partnership with Science Rendezvous, we launched a helium-filled weather balloon to the edge of space on May 9, 2015. The balloon carried with it a payload of sensors, and a video camera, collecting data during the ascent.
The launch took place at Science Rendezvous, a community event held to introduce the general public to science.
Take a look at this webpage where we present photos, video and some of the data from the launch, flight and retrieval.
The balloon was a 650g latex weather balloon, measuring about 8 feet (2.5m) in diameter when filled. Latex is lightweight and able to be stretched many times its original size. This is necessary because of the air pressure difference between the ground and the stratosphere; the balloon will stretch, enclosing a volume over 50 times greater than its volume on Earth. Connected to the balloon was a parachute, and to the parachute, the payload.
The payload was a medium-sized snap-lid food container. The 1080p camera was positioned so that it looked outward, toward the horizon. The sensors which measured atmospheric conditions were mounted externally. A SPOT GPS transponder was included to transmit the location of the payload to assist in retrieval. The GPS sensors, batteries and circuitry were contained inside the unit. Hand warmers were used to keep the internal temperature of the payload in a range suitable for battery operation (in a previous launch, the batteries rapidly died as a result of the sum -40°C temperatures). The container was insulated with styrofoam where possible to help keep the temperatures high.
The launch took place at the University of Ontario Institute of Technology North Campus during the 2015 Science Rendezvous on May 9, 2015. 1 hour prior to the launch, Transport Canada was notified, as well as the nearby Oshawa airport to ensure we were cleared for launch.
The balloon was filled, payload attached and the balloon was released following a countdown from the crowd. Watch a video, and take a look at some photos of the launch below.
We were concerned with the balloon not clearing the nearby buildings, but it had no problem rising quickly enough. Watch the video of the first few minutes of ascent, as seen by the payload-cam.
That's a bit rough during the first few seconds. We've created a visualization in Google Earth, using the GPS data the balloon collected, to give a better (or at least smoother) idea of the ascent path.
Read more about the flight below.
Prior to the launch, we had run a flight path prediction (using predict.habhub.org) and saw that the balloon should travel east, landing just north of the lake, near Brighton, Ontario. See the prediction in the video below:
The balloon ascended more quickly than anticipated, averaging 4.4 metres per second. This is likely a result of overfilling. Since a higher ascent rate means less time for the balloon to be blown laterally by winds, the landing location was not as far away as anticipated. Overall, the balloon travelled only 66 kilometres from campus, landing 10 minutes east of Cobourg, Ontario.
In a prior launch, the video camera battery died after about 30 minutes due to the extremely cold temperatures at high altitudes. Consequently, we did not capture the entire height of the balloon. For this launch, we insulated the container, used a triple-capacity battery, and included "hot-pocket" hand warmers to try and keep the batteries at a working temperature. It worked and we got video recording (and data collection) for the duration of the trip.
The flight lasted about 150 minutes (2.5 hours), with the balloon bursting at 110 minutes into launch at a maximum altitude of 25308 metres (25.3 kilometres/83000 feet). Then the parachute deployed and the balloon took 40 minutes to travel back to Earth.
Take a look at the incredible video of the balloon at peak altitude. At this point, the balloon has swollen to over 50 times the volume, stretching to almost 5 times its original diameter. Eventually, the latex is stretched past its failure point and it bursts. Fragments of the burst balloon were captured on camera. The blue "sky" is seen as a tiny strip above the earth on the horizon, separating our planet from the black of space.
Unfortunately, we do not have the final ~20 minutes of video before landing. We presume the landing was violent enough to cause data loss on the memory card and the preceding video was lost.
We will post the entire video of the flight, but, since it is over two hours long, we created a short 10-minute montage of various parts of the flight. If you only watch one video on this website, let it be this one.
The on board sensors recorded a lot of data, most of which is presented below. On all of the plots, the red dashed vertical line represents the point where the balloon burst, and consequently, the maximum altitude of the balloon.
As the balloon rises, we see pockets of high humidity air in the above plot. The transition to the stratosphere occurs around 75 minutes; the temperature begins to rise again, peaking near the burst altitude.
The styrofoam insulation and chemically activated hand warmers inside the payload were very effective at keeping the batteries at operable temperatures. The lowest temperature the payload experienced outside was less than -60°C, while the payload stayed above -5°C.
Here is the entire 2+ hour video. This is useful is you would like to cross-reference the data in the charts with the payload camera observations.
If you'd like to contact us regarding this project, please feel free to contact Kyle Mills at firstname.lastname@example.org.