Recap of EOSS-82/83

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Recovery of the Errant Payload

by Larry Cerney, K�ANI

Today (webmaster note: August 13th, 2004 I think) Mark Young, KC�RIA, and I headed back out to Deer Trail to fly the EOSS-83 descent track to search for my wayward payload. With the help of Rick, N�KKZ, calculating the search area based on the assumption of the package separating in the post-burst chaos and three different descent rates, we nailed it.

I picked Mark up at his hotel and delivered him to DIA to pick up his helicopter. I then headed out to Deer Trail. I arrived just as Mark swooped in for a landing. I loaded myself in to the helicopter, strapped in and off we flew to the area of interest.

We flew to the area of the burst and lined ourselves up to head down the descent path. Within minutes we were flying past the first estimated landing site which I had covered Tuesday. Moments later we were at the second site which I had only been able to view with binoculars and hadn't seen or heard anything. We flew over a small knoll and very close to the third estimated landing site, down on a cattle trail in a minor gully, was the payload.

Mark circled around and landed and we went out to recover the payload. We both brought GPS's to mark the location, but naturally the GPS's didn't match. I recorded 39-40.190N by 103-53.878W and Mark had 39-40.203N by 103-53.878W. Which only goes to prove "A man with one GPS always know where he is, while a man with two GPS's is never quite sure."

Well, the batteries are dead. The damage from falling from ~93 Kft was very minor. Although, I haven't been able to get my POS PacComm TNC working yet. I'll diagnose that in a while and report.

by Rick von Glahn, N�KKZ

The K�ANI-12 APRS system managed to detach prematurely from the payload train and descend to the ground without the benefit of a parachute.

Because this has happened twice in a row at EOSS, I decided it was time to create a new feature in Balloon Track for Windows, specifically the "Separated Payload Finder" that would assist in tracking down payloads in similar situations.

While the vast majority of separated payloads will depart the payload train at burst, this isn't guaranteed. So, I've created a new routine that will plot the touchdown location of a payload for every data record available and recorded during the entire flight.

While the map above looks like a flight track it is actually the position of all the possible touchdown locations of a separated payload.

Zooming in for a close-up, here is where the payload landed and where the program predicted it would land assuming a 2500 fpm (sea level) descent rate and a separation at burst. The other locations are where payloads would have landed had they detached at the indicated altitude prior to or after burst.

Looks pretty miraculous doesn't it? However, we were unsure of the actual descent rate and so did three calculations. One at 2500 fpm, one at 3000 fpm and a final at 3500 fpm. So there is a swath approximately 1.5 miles long that covers all that territory. The above maps are for the 2500 fpm descent rate. So, this isn't a guarantee. If we had only run a single prediction using 3500 fpm the touchdown would have been in a different location:

You can see that we would have been looking in a location approximately 1 mile to the west of the actual touchdown.

So, the good news ... K0ANI-12 is home in the hanger, the bad news, this new Balloon Track routine will help but not be a miraculous finder of lost payloads.