Bang Fai is not a military exercise but rather a local version of rain dance. The origin of the festival predates Buddha and it is held annually in Laos and in some parts of northeastern
Thailand. The general idea was to shoot rockets up in the sky to wake up the rain god (Phaya Thaen) and
kick-start the rainy season to bring
much-needed water to the rice fields just as the rice planting starts. Later. Buddhist merit-making was added (Bun) thus making the festival "relevant" even as the religious base of the agrarian society changed away from its animist origin.
In Thailand, the biggest rocket firing takes place in Yasothon every second weekend in May. The festival starts Friday evening with concerts of "mor lam sing", the local folk singing. The city's main road is blocked for traffic and about a dozen stages are built to host the shows – music, raunchy skits,
comedy, and traditional dance all at maximum decibel and plenty of alcohol.
Saturday, the main street is taken over by parades with floats and dancers that start / end in temples.
Then Sunday, it is time for the rockets to be fired. Apart from the serious business
of rain-making, there is a competition to be the local rocket champ. The
team whose rocket goes the highest is declared the winner. Points are also given for beauty of the vapor trail.
For any team
whose rocket doesn’t get off the launch pad, it’s tradition that other teams or spectators dump them
in the mud.
At Yasothon, the competition rockets come in three sizes, Meun (10,000), Saen (100,000), and Lan (1,000,000), but this year, there were no lan rockets.
Bang Fai Lan are nine metres long and charged with 120 kg of black powder. These may reach altitudes reckoned in kilometers, and travel dozens of
kilometers down range (they can go in any
direction) while Saen merely disappear into the clouds. Many rockets have parachutes, but most fall where they may.
For more details on the history behind Bun Bang Fai, check out
http://bun-bangfai.blogspot.com/2009/05/rocket-festival-in-transition.html