Volume 2, Issue 1 --- February, 1992

This is the electronic version of the Stratosphere Newsletter. Occasionally final editing is done to the actual layout of the newsletter and spelling checks, and other corrections may not make it into this edition. The content is complete (except for graphics).


Happy Birthday EOSS

A year ago, a small group of people, still excited about the successful WVN balloon flight of November 1990, met and decided to form an independent organization that would promote science and education through amateur radio and high altitude balloons. Thus was born Edge of Space Sciences.

In the year to follow, three additional balloon flights took place, each more sophisticated and with more people involved, and most importantly, more students involved. Each of us have our varying opinions as to the success of the individual balloon flights, but there's little doubt that it has been a very successful year for EOSS.

Now with 1992 upon us, it is time to plot our path for the coming year. Most important to this task is the election of officers, which will take place during the February meeting. Our nomination committee has been busy creating a slate of candidates from which to choose. Nominations will also be taken from the floor. I urge you to make sure your membership is current, then participate in this very important event.

Speaking of memberships, 1992 membership dues are due. Unless you joined during October, November or December of 1991, your dues are due. This is new policy voted by the attending membership at the January meeting.

Please note that our meeting date and place have changed. We just grew too big for The Pines. We will vote on a more permanent arrangement at the next meeting. If you have an idea, check it out first, and propose it during the meeting. We thank the people at the Pines for accommodations during the past year. As you can see, the February meeting is very crucial, make every effort to be there.

I have enjoyed serving as President of EOSS, and look forward to continue serving in any capacity I can. I especially want to thank all of you for making our first year, the great year it was.

Return to Contents

From the desk of the EOSS Chief Scientist

I'd like to recap the launch of the Humble Telescope from my perspective. Although we got the thing launched and provided some interesting tracking/plotting experience for the young students, I feel we were spread a little think on personnel.

Spacecraft integration, the separating of the total task, something we hadn't done before, seemed to work very well. Telescope construction was conducted at one location, camera/winder design construction at another, spacecraft construction and electronics integration at yet another. The three groups involved were in constant contact with one another on the two meter band. I felt the "up-to-the second" interchange was commendable. If nothing else we have proven that Hams can communicate and in so communicating bring about the accomplishment of an objective. In the future we need to follow up what we learned here and perhaps split and diversity even further in order to alleviate one person or even several groups from having to expend hundreds of hours on an avocational task. Too much time spent away from family causes problems... and eventually becomes drudgery rather than a labor of love. I think we have made believers of more than a few concerning just what it takes to put together a project of this magnitude. The first three spacecraft, being built and integrated by Jack, AA0P and my self left us all but burned out. Mike, W5VSI and two university students, Kevin and Tim, along with the high school students from Green Mountain certainly took the load off Jack and me.

I earlier alluded to talent being spread a little thin with so much available within the ranks of EOSS. One place in particular where I noticed this is the Balloon Team. Merle, K0YUK, could use a few more players on his team. He researches balloons and balloon operations to a "fine art", and then does everything from the balloon ordering to the actual launch. He buys and transports the helium. He fills and launches the balloon. He still has the energy to function as our treasurer. He's EVERYWHERE! I'd like to see about a ten person team helping Merle continue his fine job. The mishap we experienced, I believe, could have been averted if there had been more experienced help available.

Possibly a note of explanation is in order here. We were launching a totally new lift mechanism, a zero pressure balloon. We didn't fully understand its behavior or flight characteristics. The rigging was totally new that we employed, a never tried before, cut down mechanism and associated wiring. We experienced some shroud line tangle between parachute and shroud line spreader (and at a very inopportune moment where we didn't need a little frustration). We had an eleven knot wind with which to contend, something we had not previously experienced. We had a ten pound payload versus four pounds in the past. With the breeze we didn't have sufficient rocks/bricks to keep the protective plastic ground cover in place. In the last few seconds, prior to launch, tie ups and hook ups could have been served by more tenders. Sue, N0GUT, stepped in and her observations, assessment and quick thinking helped us immensely at that moment of all thumbs (and very cold ones at that). In the future, I'd like to see more choreography - planned, rehearsed and practiced. If we had just 20 more seconds to stop the show as the balloon was in mid-air and done an valuation, I think all would have proceeded much smoother. I thought the tug of the balloon that I felt was sufficient to lift even me. I had not expected the balloon's lifting power to "mush" under load. The arc of the spacecraft at the end of a tether must be sufficiently high to allow the penduluming spacecraft to miss the ground.

BIG LESSON LEARNED HERE, from now on all spacecraft large and small should be equipped with at least a 25 foot, if not a 50 foot tether cord or "painter" just in case a wind comes up. This would allow the load to clear objects and the ground while the load is being acted upon by another force, in this case the balloon. We will in the futures, have a "painter handler" assigned.

In summary, I view this as a learning experience that there are plenty of accolades to be laid. Tom, N0KSR, did a superb job (as always) of student/project interface. I hope in the future we can get even more young students involved in our science projects and thinking about careers in the scientific disciplines.

In Marty, WA0GEH, I think we finally found a Public Relations person. He could use a staff to help with the hours of "leg work" required to get EOSS and the participating students recognized and provide the community at large with information that today's youth, tomorrow's citizens can and are spending their spare time pursuing interesting and worthwhile activity. I think you will agree that all the youngsters we have encountered have interested parents behind them, which is a basic requirement. Now, maybe we can reach out to some of the less fortunate.

The Ground Station Crew, under the leadership of Marty, N0NTH, did an excellent job with their limited resources. I'd like to see some equipment donations (antennas, preamps, power supplies, rotators/control boxes, control cables, short tower sections, guy wire, etc.) being amassed and put in a central place, to be made available for launches and emergencies. The net control operation was very well orchestrated by Richard, WB5YOE, assisted by Eileen, WD0DGL.

Not enough can be said about the "Fox Hunters." Greg, K0ELM, sure puts together a team and with th assistance of the Colorado Repeater Association, they're unbeatable. I would not choose to be a "bootlegger", "heckler" or general nuisance in any town where I even thought Bob, WB4ETT might be lurking.

Return to Contents

Payload Power Packs

The last two EOSS balloon launches utilized batteries obtained from surplus tactical satellite communications power packs. These power packs contained 10 D size cells, each rated at 3 volts, 18 AH at a nominal 250 mA drain rate. The cell chemistry is lithium based (lithium sulfur dioxide) and exhibits one of the highest energy densities and lowest internal impedance available today. A five cell system weighs just under 15 ounces! The date code on these batteries showed a mfg. date of 09/87. This was not a concern because of the self discharge rate for these cells is less than 2 percent per year at room temperature.

During the last launch all signal and control systems with the exception of the backup beacon were lost approximately 2 hours into the flight when an additional load was placed on the system battery. Upon recovery of the payload it was determined that the battery pack was completely discharged.

Because the battery was suspect, a new cell was tested under similar flight conditions to determine its true capacity. The values obtained during testing were multiplied by 5 to give the approximate battery voltages.

In the first test, a fixed load of 1 amp was placed on the cell at room temperature. The battery voltage read approximately 13.5 VDC. After 1.5 hours had elapsed with this load the battery still read the same. At this time the cell was cooled to 0 degrees C with the load remaining at 1 amp. One half hour later (two hours into the test) the battery voltage read approximately 12 VDC. At this time an additional load of 2 amps (3 amps total) was placed on the cell. The battery voltage immediately dropped to 10.5 VDC and continued to drop linearly at approximately 1 volt per 10 minute rate. Thirty minutes later at this 3 amp discharge rate the battery voltage read approximately 6 VDC. The test was terminated at this point.

Because normal system requirements are estimated to be approximately 1 amp at a nominal 12 VDC a second cell was tested at 0 degrees C at a 1 amp constant current drain. The battery voltage read approximately 13.3 VDC. Three hours later the battery read 12.9 VDC. Four hours into the test the battery read 11.85 VDC. The battery voltage continued to drop linearly at approximately 0.7 Volts per hour.

This data tells us that anytime we increase the load on these batteries we drastically reduce the amp hour rating. In this case from 18 AH at 250 mA rate to 4 AH at a 1 amp rate. We have also learned that these batteries exhibit a graceful discharge characteristic which may allow us to sense pending low battery conditions.

In summary, I feel these batteries continue to be the best choice for future flights and if any other system is contemplated, they should be qualified under real world or edge of space conditions.

Return to Contents

Ground Station Rumblings

It's not earth shaking news to find out that others on the ground team would like to have better TVRO from the EOSS battery driven balloon ballast broadcast.

We have a problem with either the connector on Dave's (W6OAL) 70 cm antenna or a problem with the coax that Jack (AA0P) has been kind enough to loan us.

The ground station team would like to make arrangements to borrow the following for launches:

  1. Long length (100') of coax with N connectors
  2. Preamp for the above
  3. High gain horizontal polarized antenna

Call Marty Hill (N0NTH) with our offers. But please, don't all call at once!

ed note: Since the launch, the coax used was found to be defective, the antenna is fine. We need to plan more for these emergencies.

Return to Contents

Education Reviews

Oh no, the payload hit the snow bank, the payload is tilted to the right, the communication is lost, night time searches, why me? OK, Ok so the launch didn't go like a Space Shuttle mission where if anything goes wrong they delay the mission. Let's review the EOSS motto, "PROMOTING SCIENCE AND EDUCATION THROUGH AMATEUR RADIO AND HIGH ALTITUDE BALLOONS". Are we achieving our goal in that arena?

Tim Kelliher, a CU student, who was one of the science project leads told the Denver Post, "I've learned more in this experiment than in three years of college." I took a moment to think about what Tim meant. I think the learning about the experiment is self-evident. The "project" was simple. Then came the tough part, the organization it took to put that telescope in the air. Enter EOSS and Tim learned much about the surrounding factors that go into a "simple" project. I'm confident that throughout his life these are the learning experiences he will fall back on to be successful in the job environment.

Suzanne Wahrle from the Association of Astronomical Studies learned about the tropopause and why there are temperature differences during the ascent and descent through the troposphere and stratosphere. She took that back to class and this information helped her get an "A" on a science test. Getting the AAS involved with EOSS has opened question about the lower atmosphere and these students have started implementing studies on different aspects of the lower solar system.

On launch day from Eaglecrest high School some of the parents came to see what their child was doing with this project. Their comments were that their child has not shown interest in anything concerning learning until the involvement with EOSS. "That's all he talks about and I had to come down and see for myself", one parent was overheard saying. The fact that each Eaglecrest student was dedicated to the project and their function, was seen by the participation at the meetings.

Forget reading, writing and arithmetic for a moment and take a different look at where EOSS has been successful in education. No project this size can be anywhere near what we have without the organization in planing that we do during general meetings, PDR, and CDR. I know some students have said, "Not another meeting!" By the way, we had four meetings at Eaglecrest besides the EOSS meetings. Toward the nearing of launch day the students could not wait for the next meeting. My point is that EOSS offers some real world application of putting a project together. I don't know if any classroom offers that.

All the students did a wonderful job and deserve much credit to the success of our mission. But, a special thanks needs to be expressed to the parents of the students who made sure the kids got to the meetings, put up with late night returns from those meetings and supported their child's interest.

I'd also like to thank Terry Conley, John Christensen and Tom Frayer from Eaglecrest High School for their efforts in support of the whole event, as well as, the Cherry Creek School District for their public relations efforts.

Are we doing the job of education? "Hey, Tom, I was on the news!" What more can I say.

Return to Contents

Humor (?) from Marty, N0NTH

As the president of a not for profit corporation I am sure that you are aware that it is illegal for the group to end its fiscal year with large sums of money in the bank.

I have s suggestion for a place that EOSS could donate the large sums that we have accumulated over the past 12 months. My suggestion would be the very respectable and well known charity, The Retired Hot Air Balloon Pilots Home.

Return to Contents

Food For Thought

Since I've never been short of suggestions, here are some that I think we as a group should think about and discuss, and I welcome yours.

  • Instead of sending continuous CW and packet messages, just send packets once every 30 or 40 seconds with the transmitter off in between messages. Reduce the power of the two meter packet transmitter to something like 800 milliwatts. This would cause less interference to the rest of the payload and would help conserve the battery supply.
  • Use a low power self sufficient two meter beacon for the T-Hunters, during the flight and after touchdown. Suspend this xmtr down below the normal payload to keep from desensing the command receiver.
  • On touchdown, this packet xmtr can still intermittently send out either CW or tones or packets to assist the hunters in case they don't hear the normal beacon, as this xmtr will be running more power.
  • Put the command receiver frequency at the opposite end of the band of the frequencies used by the packet and beacon xmtrs. Since normally the commanding is done when the packet transmitter is off, desense should not be a problem. However, if the packet should lockup and not go off due to say a computer hangup, then a ground command station with a beam and reasonable power should be able to command it or reset the microprocessor.
  • Do not run continuous CW. Use CW in special cases such as, the packet fails, or some data on the experiment package needs to be sent.
  • Do not run the TV all the time. Use during the launch up to a few thousand feet, then a few times during the ascent phase to see how the package is doing, then use during the release of the balloon and most of the way down to try and identify the landing spot.
  • Monitor the battery bus and send voltages on each packet. If battery drops below a critical value, have the computer dump unnecessary loads, such as the TV and any experiment package loads. If this condition occurs, the packet should immediately notify the ground station of this failure and let them decide whether to try and command them on again or what action should be taken.

Return to Contents


In keeping with ARRL goals, EOSS has provided an opportunity, through the Hams in our club, to introduce amateur radio to the people in our community. We have shown through our projects that being a ham can be fun. Although we are set up to be a science club, I believe we still need to stress the fact that "through amateur radio" is in the club motto. EOSS is just a new medium through which we amateurs can reach our goals of promoting our hobby. It was nice that EOSS got that press, however the public needs to also know that amateur radio is a provider of community service along with AREA, public service events, and weather service support, to name a few.

We have seen the news beat our doors down when we operate DX during a world disaster and air a ham working his station to pass health and welfare messages. That's the public perception of amateur radio. What we do on a local basis is lost in the wash. It was a joke one time when I got a call from a major media station about finding a ham station that was working DX after an earthquake somewhere and the next day we were providing radio for one of the events the station sponsored. I think at every opportunity the hams of EOSS should remind themselves that they are part of a community service provided by amateur radio and remember their roots when it comes to public relations.

Return to Contents

Letter from Eaglecrest

I would like to thank Edge of Space Sciences for enabling several of our students to participate in the Solar Telescope Balloon Flight on January 4, 1992. The opportunity they had to work with students from other high schools, college students, engineers, communications experts, and ham radio operators on a project of this nature is most significant. The experiences gained will lead to both useful careers and/or lifelong hobbies for many.

I also appreciate the positive publicity our school received on Channels 4,7,and 9 and in the "Denver Post". This is important to us as we are a new school that seeks to establish a tradition of being an excellent academic institution that provides all of its students unique and meaningful opportunities. This project was a prime example of what we like to offer.



Terry Conley

Return to Contents