[balloon-makers] RE: Solar Balloon

Rochte, Robert rrochte at gpacademy.org
Tue Jun 24 07:45:02 CDT 2003


>On 21 June at about 9:30am, William H. Appleby (Bill) wrote:
>I saw your post on the balloon maker's page and found your site
>to be inspiring.

[Bill's questions are interspersed amongst the text below.]

Bill:

Thanks so much for writing.  Sorry for the delay in responding to your email
- it ended up lost in the noise on Sunday and I just read it this morning.

The "Spirit of Piccard" balloon actually flew this past Sunday.  Launch was
around 9am in Sterling Heights, Michigan and it was tracked to just south of
metropolitan Detroit at an altitude of 26,000 feet when I lost contact with
the payload.  I was pleasantly surprised to receive a voicemail later that
evening from a man near Columbus, Ohio, informing me that he had found the
balloon (he actually saw it fly over his house and then descend into a field
about 400 yards away).

The balloon was reported by numerous commercial pilots to be at an altitude
of 31-32,000 feet (this might have been the stable float level) over
southern Michigan about thirty minutes after I lost contact with it.  It was
later reported (about 3:45pm) to be at 24,500 feet about 20 miles south of
Findlay, Ohio -- heading south and on its way down.

I don't have much more data yet, since I lost all telemetry after only two
hours and I haven't yet retrieved the balloon (I'm driving down on Friday).
I suspect that telemetry was lost due to a radio or modem (TNC) failure --
my initial thought was that the LiSO2 battery had failed, but the audio
beeper (to aid retrieval) was still going strong the next day when I
actually spoke to the man who found it.  

The early (by my estimates) descent may have been due to thermal problems
with the envelope (i.e., the convective cooling in the low stratosphere
would be much less than at the surface, so the temperature of the envelope
could have risen high enough to soften and split open at some point).  I'll
know more once I download data from the temperature logger that was
suspended inside of the envelope.

>I was wondering if you are affiliated with any of the groups mentioned in
the below web 
>sites or are doing this totally independently. 
><http://www.amsat.org/amsat/balloons/balloon.htm>
><http://users.crosspaths.net/~wallio/HABLinks.html>

As far as affiliations, I'm not involved with any of these groups.  Other
than student involvement here at the Academy (limited thus far, but we're
developing a program for students in K-8 next year) and the sage advice of
Don Piccard on many issues, this has been a solo endeavor on my part.  No
doubt I've gleaned a lot of information from the EEOS and other web sites
(e.g., like using twisted Dacron - kite string - instead of monofilament
nylon for the payload suspension line), but I've had nothing at all to do
with these other groups.

>Where did you acquire the large sheets of material in your envelope? 

The film used in constructing this balloon was obtained from... Sam's Club!
Those large panels along the equator of the balloon are nearly complete 55
gallon trash bags, split open along the edge (each panel is about 6 feet
across).  At first the idea of using trash bags as a source of material was
due to simple economics -- I couldn't afford an entire roll of film, but $12
for 72 drum liners was in the budget.  It turned out that smaller panels
made working in my relatively small office (and occasionally at home) much
easier.  Sets of panels could be cut using only 6'x6' of floor space and
assembly could be done incrementally, as time permitted.  In the future, I
will almost certainly use large rolls of film -- the convenience of small
panels is ultimately outweighed by the added work involved in sealing all of
the additional seams.

>I am a member of several airship and HAM balloon list servers and would
>post your progress there but will not do so without your assent. 
[snip]
>Your research stimulates lots of questions, but I am not going 
>to pummel with them.
 
Please feel free to post anything you'd like about the project.  I am
working on the documentation of the actual flight right now and should have
it posted (with pics of the launch and recovered balloon) by this coming
weekend.  I invite your questions -- they will almost certainly lead me to
new answers as well!

In the meantime, you can view the recorded track of the balloon (copied from
the Findu.com results) using this URL:

http://mail.gpacademy.org/~rochter/track.htm

The data points represent individual position reports, sent every minute.
The last point at the bottom of the map is the final position report that I
received -- about two hours after launch.

There is a picture from the launch (don't mind the funny-looking guy
releasing the payload - he'd been up all the night before!) at:

http://mail.gpacademy.org/~rochter/flight5.jpg

As I mentioned, more pics and documentation should be posted to my main page
by this weekend.

Thanks again for writing.

Regards,
Robert
-
"Balloon-makers" is archived at http://www.hombc.org/balloon-makers/





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