Far Horizons visits the NWS
Last Thursday Mark, Geza, Alan Blum and I took a journey down to the National Weather Service (NWS) facility in Lincoln, IL. Our main goal was to witness their procedure for hydrogen balloon launches. We were treated to a wonderful inside access to their facilities and the friendly staff there.
We had a chance to present some of the work of Far Horizons to the staff. We walked them through the way we launch our heavy payloads – theirs are more than ten times lighter. We also regaled them with stories of our payload retrievals – an aspect of their launches they don’t need to concern themselves with. Their data are collected via their ground-based receiver. They appeared pretty impressed by the experiments and particularly the imagery from our flights. Although they have been launching HABs twice a day for years on end, they don’t actually have a chance to see the environment they sample day-in-day-out. We ended up sharing a sampling of our video and imagery with them. Eric Laufenberg and Billy Ousley then gave us a presentation focusing on the efficiency, reliability and accuracy of their soundings. The Lincoln, IL facility is regularly recognized as one of the best and most reliable NWS stations in the US.
They’ve launched with hydrogen safely and effectively thousands of times over many years without incident. They really helped dispel the myth of the insurmountable danger of hydrogen as an effective lift gas. Of course, they are able to do this owing to the fact that they have a dedicated facility designed for the safe use of hydrogen sounding balloons. If we can modify some of the methods and procedures we witnessed and adapt them for use in the field, we may be able to create a reliably safe process fitting to our own launches.
Eric was our guide to a NWS sounding launch. First, we were shown the setup of the Radiosonde including the prep of the water-activated battery used in the device. He then took us out to the launch building for the evening sounding just as the sun was setting. The building itself is designed specifically for safe H2 handling. It is thoroughly ventilated at roof level and there are no unshielded electrical equipment in the rooms where the hydrogen is present (meaning winter launches are not for the weak at heart or cold of hands). The roof is flat and has a flat dropped platform. This forces any released hydrogen to disperse and vent quickly so that even if there was an ignition event, the concentration of H2 would not be enough to ignite surrounding materials. The risk of static charge buildup has been eliminated by using a wooden prep table and a static grounding pad for technician performing the fill. Eric reminded us of the use of brass tools to prevent the chance of sparks.
He ran us through the setup, which they have down to a science. The whole procedure only takes a handful of minutes from beginning to launch (though answering our questions surely slowed him down). The H2 tanks were in a separate room from the prep table. Flexible tubing fed the hydrogen from the tank room to the fill table. The most interesting technology was the fill nozzle. It is designed to automatically shutoff when the desired lift is met. The desired lift can be adjusted with brass weights mounted on the fill nozzle. Also, if there is a rapid release of lift – say the balloon accidentally burst or separated from the fill tube – the nozzle would drop and this would also cut off the flow of H2. Billy kindly provided us their launch procedure guide that includes details on the fill nozzle design.
The launch was too simple for my liking (but not for Eric’s, I assume). There was a near dead calm on the ground that evening. I would have loved to have seen their precautions and process in high winds. They use an extremely long tether (~60ft +) that helps adsorb some of the shock from high winds. Also, the long tether allows them to hook their payload outside, clear of the building. They then run the tether into the enclosed fill room. If there are high wind conditions, they will preposition the payload and connect the balloon to the tether inside the building. Then they can simply open the doors and release the balloon without the “walkout” that we do.
Of course, for our launches when the winds are out of the south at Koerner, we have to take a long walk to clear the hanger and radio tower. In contrast, the NWS building is designed to open either to the north or south depending on the ground winds. This doesn’t mean it’s always an easy launch. You may notice to the south-east of is their radar tower. Yes, they have smacked into this in the past. Also, they have tangled in the power lines to the immediate south. But the soundings must go on. So, even the pros can’t do anything about the weather.
Finally, we all returned to the control room to see the data coming in. Their antenna automatically tracks the payload and receives data at the rate of about 1 packet every 2 seconds. These data, along with all the other soundings performed around the country and world, help to build a model of our atmosphere. It’s this model we use to perform our predictive tracks. So, cheers to the quality work done by the scientists at the NWS Lincoln and around the country.