What kind of payloads are they typically launching? Is it typically just a "see where the balloon goes" or do they sometimes include high altitude experiments or the like?
They have a recap of the payload string on the website for each launch.
Older launches way back in the day often included stuff like amateur radio cross-band and in-band repeaters (the duplexer was VERY small for the in-band and the transmitter very low powered, but you don’t need much TX power from that high up!) and various experiments on how to build trackers, DF beacons, etc.
Many early flights had a lot of electronics freeze at altitude and stop working for a while. Sometimes recovering in the descent, sometimes not. They had a lot of things to work out back then in terms of electronics health in the cold, “cut down” commanding to force the balloon to pop or the string to disconnect if needed, even color video downlinks were pretty difficult back then.
Just looking over the website, the last launch appears to have had ten college student’s payloads aboard which are usually scientific experiments the students compete to get aboard. Metro State’s “Space Demo Sats” and CU Gateway to State payloads. Ten of them.
They usually don’t publish the student’s payloads on those flights since that’s up to the college whether or not they feel like doing that and EOSS are just the tech support for flying the payloads. Most are something related to the student’s learning curve for eventually going to work in spaceflight engineering. Or at least earning their degrees in such, anyway.
19.3 lbs and a 12’ parachute for the trip down. Beefy!
They also are required to bounce the payload weight down into the “exempt” category when cloud cover is present at certain altitudes, ostensibly for protection of IFR/IMC traffic. I believe that’s a requirement of their standing waiver but not sure.
They pre-plan that ahead of time and will split payload strings and launch more balloons, or they’ll take things off the strings altogether, depending on the contingency plan they’ve worked on prior to launch day. They try not to disappoint the students these days.
Back when I was helping out long long ago, as a DF team chaser, the strings and balloons were a LOT smaller. Many of the original team members from back then have had enough time to retire and move to other states.
A number of them started more launch groups doing volunteer collegiate work similar to EOSS.
The Arizona group was somehow involved in that balloon that flew all the way around the planet multiple times a few years back and they’re pretty active down there with other launches also, I hear. I never quite figured out their role in it, but watched the balloon location tracking websites and listened for the beacon as it flew over a number of times. Pretty cool stuff. Went around a whole bunch of times.
I helped set up some audio links so the Colorado folks (many who were cheering them on as old friend) could listen in in real-time with their radio communications many years ago. I believe they’ve stopped doing that, but many local ham operators enjoyed listening in on the launches and recoveries from another state. Even that was a decade ago now, I think.