CHASE-1 PDF Print E-mail
Written by Joshua Neel   
Wednesday, 19 October 2011 19:54

CAP High Altitude Stratospheric Experiment (CHASE-1)


On Saturday October 22nd, The Fort McHenry Composite Squadron launched it's first high altitude weather balloon experiment!  The objective of the mission was to send a payload to the stratosphere with a camera to capture images of the flight.  The launch took place in Clear Spring, MD at the Clear Spring Volunteer Fire Co with a liftoff at 8:21:50 AM EST.  The balloon filled with helium ascended at a targeted rate of 1000 feet per minute until it reached its bursting altitude.  Amateur Radio enthusiast Richard Goodman reported he was able to track the balloon the altitudes over 90,000 feet!  After the balloon burst, the payload safely parachuted down back to the ground and a Ft McHenry ground team located and recovered the payload 63 miles away in Pinetown, Pennsylvania.  During the flight, the payload was transmitting it's GPS coordinates using Amateur Radio and the Automatic Packet Reporting System (APRS) network.  The Amateur Radio callsign of the balloon was KB3VTP-11 and the flight was tracked in near real-time on the APRS website


Here is a flight prediction of CHASE-1 courtesy of Pat Kilroy N8PK

The Payload

  • APRS Tracker built from an OpenTracker+ SMT, GT-320FW High Altitude GPS, and SRB MX-146LV transmitter from operating on 144.390 MHz
  • Antenna made from romex electrical wire enclosed in PVC
  • Morse Code Beacon from Big Red Bee operating on 433.920 MHz
  • Canon A560 running CHDK (Canon Hacker Development Kit)
  • Enclosure made from styrofoam wrapped in bright orange duct tape from Hobby Lobby
  • 800g sounding balloon from
  • 3 foot parachute from
  • Radar Reflector made from foam board wrapped in space blanket material
  • Android HTC Incredible running APRSDroid as a backup tracking device



In the weeks before launch, the Fort McHenry Composite Squadron was very fortunate to have two special guests come and discuss some of the aspects of high altitude weather balloons.  Bob Bruninga, the inventor of APRS, gave an excellent presentation on the APRS system.  He also showed the cadets how to do direction finding with nothing more than a hand held radio!  NASA engineer Pat Kilroy discussed simulated satellites using weather balloons and demonstrated tracking hardware the size of a credit card capable of transmitting morse code telemetry.  See for some of the other cool projects Pat has worked on.  Pat was instrumental in getting our mission ready for launch by sharing his expertise with everything from payload construction, to balloon filling operations, and everything else along the way.  We owe a special thanks to Pat and Bob for their contributions to the mission!

Left to right Bob Bruninga, 1Lt Josh Neel, Pat Kilroy

As we got closer to the launch date, the cadets learned how we would be tracking the payload, and reviewed the current flgiht predictions based of the winds aloft.  We even exercised our math skills in determining how much helium we would need to get our payload off the ground and achieve the right ascent rate.   With the final weather predictions looking good we were ready for launch!



The night before launch we called the Washington Center ATC Facility to notify them of our launch in accordance with Federal Aviation Regulations (FAR 101).  Dark and early the next morning the launch crew met at the Catonsville Armory at 05:00 AM EST to begin our journey to the launch site in Clear Spring, MD.

The crew consisted of:

Senior Member Janet Dean
First Lieutenant Charles Frater
First Lieutenant Josh Neel
Captain Cajetan Von Der Linden
First Lieutenant Andrew Wortman

Cadet Technical Sergeant Sarah Cohen
Cadet Senior Airman Timothy Jacobs
Cadet Airman Eugene Nash
Cadet Technical Sergeant Ryan Payne
Cadet Airman Kira Stiers

Shortly after arriving at the Clear Spring Volunteer Fire Co we were greeted by volunteer fireman Michael Main and the crew got to work filling the balloon to achieve the desired lift.  Meanwhile final checks of the payload electronics were performed to ensure everything was operating correctly.  The proper lift was achieved by counter weighting the balloon with a jug of water filled to match the desired lifting force and the balloon was filled until it achieved neutral buoyancy.  We were joined by Pat Kilroy from NASA who helped oversee the operation and ensure a smooth launch.  Pat also provided some great pictures of the mission as seen below.

Image Courtesy of Pat Kilroy

A half our before launch, 1st Lt. Charles Frater contacted Washington Center per FAA request and they replied with the beautiful words "Your flight is approved!"  The balloon was then attached to the balloon train consisting of a parachute, radar reflector, and the payload.  After performing some final checks the launch team carried the train to a nearby field and we were ready for launch.  After a short countdown we successfully launched our payload at 8:21:50 AM EST.

Image Courtesy of Michael Main

Image Courtesy of Pat Kilroy

The Chase

Image Courtesy of Michael Main

Image Courtesy of Michael Main

After enjoying the sight of the balloon gracefully rising and disappearing into the cloud layer, the crew piled into the chase van and began traveling along the predicted flight path.  Meanwhile Pat Kilroy began an independent search with his own APRS rig built in to his car.  The hunt had begun!  We began monitoring the APRS packets and our excitement began to rise along with the reported altitude of the balloon.   12,867 feet, the payload was on its way!  We were not receiving every packet transmitted but we were getting enough updates to keep us on track.  32,321 feet, 45,663 feet, stratosphere here we come!  And then...  nothing?!

Image Courtesy of Pat Kilroy

We lost contact with the payload at 9:05:24 AM EST.  We waited in desperate anticipation but things were not looking good.  The crew decided to continue driving along the predicted flight path to Lewisberry, PA which was the closest town on our map to the predicted landing location.  We kept driving along in radio silence guessing where the payload was based on predictions.  We knew by 10:00 AM EST that the balloon had likely burst and was on it's way down, but we didn't know where.  Then at 10:03:04 AM EST with excited relief we got a report that the payload was at 54,285 feet.  It was on it's way down and just overhead of us, right on target for the predicted landing location.  We received a few more reports showing that descent rate had slowed indicating the parachute had opened and the payload was safely returning.  As we got closer to Lewisberry, we were met again with frustrating silence!  We received our last position report from our radio transmitter at 10:16:20 AM EST indicating an altitude of 14,621 feet.  Once we arrived in Lewisberry, we stopped and began to try to determine our search radius from our last location.  A few moments later at 10:33:43 EST we received a report from our backup tracker running on an Android phone indicating the final landing coordinates of the payload!


The final coordinates indicated that the payload landed in the nearby town of Pinetown, PA only 2.5 miles from the predicted landing location!  The location appeared to be in wooded terrain adjacent to a residential area so we stopped at a nearby house to ask who the landowner was.  We were directed to the landowners home a few houses away and the landowner graciously agreed to let us search the property to recover the payload and showed us where we could park.

Just as we got out of our van and started a briefing before entering the woods we were joined by Bob Bruninga, the father of APRS!  Bob was informed of the launch earlier in the week and had joined the hunt.  We were informed that a local Amateur Radio enthusiast Richard Goodman WA3USG, was able to maintain direct contact with the payload and helped Bob and a few others determine the whereabouts of the landing location.  Bob had then used radio direction finding techniques to pinpoint the same location of the woods we were preparing to enter.  Shortly after we joined by Pat Kilroy who also was able to locate the landing location.

After a thorough briefing, given by ground team leader 1st Lt. Andy Wortman,  we entered the woods to begin our search.  We used visual scanning to look for any sign of the payload as well as RDF techniques using a beam antenna monitoring the signal of our UHF Morse code beacon.  We followed the signal until it was strong enough to pick up without an antenna.  Then we stopped to use body blocking techniques with the antenna removed to get a direction of the signal.  Shortly after determining the general direction of the signal,  C/TSgt Ryan Payne. got a visual of the payload!

Image Courtesy of Pat Kilroy

Much to our surprise the payload had landed upright resting peacefully on the ground while the remains of the balloon were in the tree tops with the whole balloon train in tact.  After determining the scene was safe we easily recovered and silenced the payload.


The onboard camera captured some amazing photographs of the stratosphere!  You can see the highlights of the mission including a video of the launch and the stratosphere as seen by the payload at  You can also see all of the 1000+ unedited images captured by the payload at


  • We owe a debt of gratitude to Pat Kilroy who was instrumental in our successful mission from start to end.
  • Many thanks to Chief Michael Reid and the Clear Spring Volunteer Fire Co, for their outstanding support and hospitality.
  • Special thanks to the United States Air Force Association for awarding us a grant to help fund the mission and to Captain Walter Murphy whose generous donation allowed us to complete our mission.
  • Special thanks to Bob Bruninga for teaching us about APRS and direction finding techniques that proved quite useful in our recovery effort.
  • Congratulations to the launch crew of CHASE-1 for a successful mission!

Will YOU be a part of CHASE-2??

Last Updated on Tuesday, 01 April 2014 19:20
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