Monday, 14 September 2015

To the Edge of Space - Slowly

The use of party balloons for flights to an altitude of about 8 km, just under the cruising altitude of most jet airplanes, has been covered here with the experiments of VE3KCL and VK3YT but other hams (and non-hams) are getting their kicks by aiming much higher with larger high-altitude balloons.

The Skies over Lake Michigan from a Weather Balloon
These types of flights are more complicated and expensive than the party balloons but no prohibitively so. Aeronautical regulations are not onerous even with a fairly sizable balloon with a weighty payload, as long as there are mechanism to slow the descent when the balloon bursts and to be able to detach the payload on command. Typically, although not necessarily required by law, air traffic control is informed of the flight and sometimes they even track it using on whatever web site is reporting the progress of the experiment.

Flights generally do not cover the same great distances as the party balloons, which makes them less exciting from the standpoint of seeing which way they will wander but allows for more interesting payloads, such as cameras and transponders using VHF and UHF communications. Typically the flights are much shorter in duration, rising rapidly to their maximum altitude then bursting and dropping by parachute.

The High Altitude Balloon Challenge web site lists some of the results achieved during their contest period in the Spring. The highest altitude achieved was 42895 m (140,732 ft), and the longest track 1,000 km (although it was disqualified as it was not achieved during the contest period).

A group of amateurs in Alberta who call themselves BEAR (Balloon Experiments in Amateur Radio) have been launching HABs over a period of 15 years and regularly achieving altitudes of 100,000 feet or more. They use APRS tracking rather than the custom system used by the party balloons, which makes sense when you have greater altitude and smaller distances.

AMSAT lists many different amateur groups doing high altitude ballooning projects on their web site.

The other big difference in the high altitude experiments is the far greater expectation of actually getting the payload back, by using chase cars and trying to engineer the recovery on farm land.

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