The Flight: August 1998
It’s almost time to launch…
The late August launch date was chosen to coincide with “fall turnaround”, when stratospheric winds change direction from west to eastward. Winds are expected to be low enough to keep the balloon within telemetry range of the launch site (about 400 km).
Aug. 24, 1998 [day one]
The MANTRA98 balloon was launched from Vanscoy, Saskatchewan at 3:25 AM local time (LT) on August 24, 1998.
(Vanscoy is a 25 minute drive (30 km) south-west of Saskatoon.)
Measurements began at 5:30 AM (LT), at which point the balloon had reached an altitude of 26 km.
The campaign was off to a good start!
7:15 AM, Aug. 24, 1998
Maximum altitude of 38.8 km was reached. Over the day, the balloon floated between 32 and 38 km altitude. Winds were negligible.
It’s all going according to plan. So far…
Here’s the location of the balloon in position and height based on its GPS:
The altitude data show the balloon descended slowly over the course of the flight. This suggests there may have been a small leak.
End of the balloon flight (?)
Now that the balloon had been aloft for its intended science mission, it was time to bring it back to the surface. There are several valuable instruments on board, worth about $500,000 (in 1998 CAD). The balloon payload needs to be recovered and reused.
9:16 PM, Aug. 24, 1998
Flight termination was attempted at 9:16 PM (LT).
Operators trigger explosive squib systems to separate the balloon from the gondola. This should result in the science payload in the gondola falling gently to the surface with the aid of a parachute.
It is not successful.
Two explosive squib systems fail to separate the balloon from the gondola.
However, the monitoring system says termination system was successful.
9:45 PM, Aug. 24, 1998
A backup termination option is triggered: a valve on the balloon is instructed to release the Helium.
This also fails to bring down the payload and balloon.
Monitoring system reports that the valve is opening & closing.
Operators leave the valve in the open position.
There is one last chance to end the flight…
11:15 PM, Aug. 24, 1998
An automatic backup system to end the flight is triggered. An electronic timer is activated to cut the cable. It also fails. No separation of payload is observed.
At this point, operators no longer have a way to bring the balloon back down. All mechanisms to do so report being successful, but the balloon continues to float away.
Next: the unexpected journey