Each button selects a particular weather model to use for
the flight prediction. There are lots of weather models
developed by meteorologists, but the ones the ARHAB
community likes best are the GFS models. They’re based on
current weather observations, including data from
radiosonde launches. GFS models are updated periodically,
depending on how short-term their predictions are.
If the launch is between eight and 16 days away, then
select the 12 hour model (as its name indicates, this model is
updated every 12 hours). If the flight is between three and
eight days away, then select the six hour model. If the flight is
less than 3-1/2 days away, then select the three hour model.
Now click on the Submit button at the bottom of the
page. The next webpage to appear is from READY, a data-base of (perhaps all) meteorological models (see Figure 4).
First, update the time and date of the launch. By
default, READY displays the most current time and date. So
if you forget to update this field, the predictions will be in
error. The time and date drop-down menu is located at the
top right of the page (I’ve pointed it out in my graphic). The
time and date are given in UTC which is several hours
later than the current US time. (See the sidebar for how to
convert your current time to UTC.)
To prevent software bots from downloading READY
data so frequently that it denies the rest of us data, you
must manually verify that you’re a human by typing the
characters displayed in the Access Code field. Now click on
the Get Profile button and wait. The Online Balloon Track
software collects the data file from READY, so you don’t
have to copy the data yourself. When the READY data has
been received, Balloon Track returns back to Near Space
Venture’s Output selection screen.
Now you get to select how to display the flight prediction.
I recommend the Plot Track on Google Maps option. When
you select this option, you get a Google Map with an overlay
of the near spacecraft’s predicted flight path (see Figure 6).
On the map, the ascent portion of the flight is colored
blue and the descent portion is red. The map is a simple
one showing roads, towns, lakes, and rivers. You can zoom
into the map for more detail. Next, try selecting the Satellite
button at the upper right of the screen. This display is an
overlay of the near spacecraft’s flight path on an aerial
image. That gives you a much better idea of the terrain your
balloon will recover in. Finally, select the Hybrid button for
a map with the roads, satellite image, and flight path of the
near spacecraft (see Figure 7).
So now you have a map, what next? Take a close look
at where the balloon is predicted to land. Is the recovery
zone located in or near towns, lakes, or forests? All those
make for a difficult recovery. If the recovery zone looks
difficult, remember you can change the balloon’s initial
volume of helium or change the launch time and place. Be
sure to run the prediction again if you change something.
Now a word of warning. The prediction of a near space
flight is not an exact science. So be sure to look around the
recovery zone for areas that you want to stay out of. It’s best
if you make a few more predictions with changes in the
ascent rate and burst altitude. The collection of recovery
■ In the Eastern Time zone, add five hours to the
planned launch time.
■ In the Central Time zone, add six hours to the planned
■ In the Mountain Time zone, add seven hours to the
planned launch time.
■ In the Pacific Time zone add eight hours to the planned
If you’re in a part of the country that obeys daylight
savings time (summer time), add one hour less (or four
hours for Eastern, five hours for Central, six hours for
Mountain, and seven hours for Pacific).
locations gives you a better idea of the recovery zone than a
single prediction will. If the recovery zone looks good, then
you probably have found an ideal flight. It’s all pretty cool,
isn’t it? If you’re interested in near space missions and
you’re located near eastern Kansas, then contact
CAPnSPACE. They’d be pleased to help you. Be sure you
tell them that Paul from Nuts & Volts Magazine sent you!
Onwards and Upwards,
Your Near Space Guide NV
May 2007 89