Bill Brown, the father of modern
American near space ballooning, was
next. Bill’s presentation covered a
variety of topics because he basically
is a master experimenter.
Bill is also a fan of long duration
near space flights. Normally, a flight
like this can only be accomplished with
an expensive polyethylene balloon.
However, Bill has perfected techniques
involving less expensive latex weather
balloons. In one of his techniques, he
seals the balloon’s neck with a PVC
pipe containing a 1/16 inch diameter
hole. The hole lets helium slowly vent
out of the balloon, gradually slowing
down its ascent rate. The decrease
in ascent rate is so slow that the
balloon still reaches near space
altitudes before the sun’s ultraviolet
rays degrade the balloon to the
point of bursting. One of Bill’s flights
reached an altitude of 107,000 feet in
its 17-1/2 hour flight (compared to a
nominal 100 miles for a flight like this).
Bill recommends launching a
flight like this in the spring and autumn
when the stratospheric winds begin
changing their direction (this is called
the stratospheric turn around). That
way, the balloon drifts slowly and
recovery takes place closer to the launch
site rather than across many miles.
One of the neatest things Bill
presented this year was the Find Me
Spot, a personal GPS tracker. As he
explained, SPOT transmits its GPS
location to Global Star satellites every
10 minutes. From experience, Bill
discovered that it didn’t transmit its
position above 60,000 feet. However,
once the near spacecraft carrying
Find Me Spot descended below
this altitude, Find Me Spot began
transmitting its location again. Even
upside down, SPOT transmitted its
GPS position to the Global Star
Satellite overhead. While a bit spendy
at $169 for the unit and $150 annual
fee for unlimited use, SPOT may be
the ultimate insurance policy for a
■ Find Me Spot, the personal satellite
tracker. (Carry one of these with
you and friends will know where
you’re at every 10 minutes.)
■ Bill Brown discussing his many
near space activities.
EDGE OF SPACE SCIENCE
Mike Morgan of Edge of Space
Sciences (EOSS) was the next speaker.
He led a discussion about using
hydrogen to fill latex weather balloons.
Like many commodities, helium
prices have recently begun to rise
(pun intended). While helium is the
second most abundant element in
the universe, its existence on earth
comes only from the decay of
radioactive isotopes underground.
As natural gas reserves are exhausted
or become too costly to pump, the
availability of helium will continue to
decrease, further raising its cost.
When hydrogen-filled balloons
get mentioned, people invariably
think of the Hindenburg. However,
hydrogen wasn’t the problem with
this great airship; the problem was its
flammable skin. As long as proper
safeguards are used, hydrogen is a
safe filling gas for weather balloons.
This doesn’t mean there aren’t risks
associated with hydrogen.
Unlike helium, hydrogen is
flammable in concentrations ranging
from 4% to 74% (a very wide range).
Hydrogen requires low energy to ignite
and may even self-ignite with a little static
electricity. Its flame is nearly invisible
to the naked eye and it burns hot.
Mike recommended to never
vent hydrogen from a tank into the
atmosphere. So, never drain a tank
of hydrogen by opening its valve;
instead, bring it back to the welding
supplier for disposal.
Other suggestions were to use a
single tank at a time to fill a balloon;
do not connect several tanks together
into a single manifold. Use stainless
steel or brass fittings; not plastic ones
as they can generate static discharge
as dry hydrogen flows through them.
Ground all filling equipment with
at least three stakes to the ground. This
includes grounding the person handling
the balloon filler with a grounding
strap. In addition, fill the balloon
slowly, as a lower flow rate decreases
the chances of electrostatic build-up.
HARP (Taylor University)
BASE (DePauw University)
Near Space Ventures
There’s more about the
Great Plains Super Launch at
February 2009 79