LIGHT HEART was the name of a balloon mission carried out by Colonel Thomas Leigh Gatch, Jr. who performed in February of 1974 an unsuccessful attempt at the first crossing of the Atlantic by balloon.
The aproach choosed by Gatch was to fly high in the jetstream using a cluster of ten transparent plastic superpressure balloons of 26 ft diameter manufactured by Raven Industries. During ascent, the balloons would expand without venting until they reached a stable density and then would maintain height. Gatch himself was in a sealed gondola maintaining 0-5 atmospheres pressure with a 40 per cent concentration of oxygen, giving the same oxygen partial pressure as at sea level.
Balloon launched on: 2/18/1974 at 19:29 local
Launch site: Harrisburg Airport, Pennsylvania, US
Balloon launched by: LIGHT HEART TEAM
Balloon manufacturer/size/composition: Super Pressure Balloon RAVEN Cluster of 10 superpressure balloons
End of flight (L for landing time, W for last contact, otherwise termination time): 2/22/1974
Landing site: Dissapeared near Canary Islands
The mission was launched from Harrisburg Airport, Pennsylvania on Febraury 18, 1974. After the initial burst of one of the balloons he reached 33,550 feet. That night and the next day, Light Heart floated on an easterly course being consistently checked in with passing airliners at 35,000-36,000 feet. The final contact was with BOAC flight 583 at 1250 hours Tuesday, 19 February, 925 miles northeast of San Juan. Through Tuesday night and Wednesday, there were no reports from the balloon nor any sightings. Gatch's team were not alarmed at this point, as they assumed that he was simply out of radio range. The Liberian freighter Ore Meridian spotted the Light Heart shortly after dawn on Thursday, 1000 miles west of the Canaries "apparently lifeless and floating far off course and at an unaccountably low altitude". Except for unproven balloon or life raft reports in scattered areas, no further information about Gatch was received since. There was an intensive search by US military aircraft and ships, as well as commercial planes and vessels, all to no avail. Gatch's sister offered a $10,000 reward and distributed flyers in likely areas with information about the flight. The balloon or the gondola were never found.