Page 8 - EngineerIT AugustSeptember Issue 2026

SCIENCE

What makes around-the-world

Pico balloon science so

remarkable?

By Hans van de Groenendaal, Science and Technology Writer

ith a cost-to-science ratio They float within jet streams. Wind speed and direction are inferred
of a few hundred rand in from GPS data transmitted back to Earth via WSPR telemetry, creating a
Wparts and an amateur radio continuous global picture of upper-troposphere and lower-stratosphere
licence, a hobbyist can generate wind patterns that would be difficult and expensive to gather any other way.
months of genuine atmospheric data
from the stratosphere, data that is WSPR stands for Weak Signal Propagation Reporter and is commonly
publicly archived and can be used by pronounced "whisper". Some Pico balloons venture into the polar regions
researchers. and, during the June solstice, can remain in constant sunlight while reaching
extreme Arctic latitudes.
But I am putting the cart before the
horse. Let me first explain what a Pico Balloons orbiting over remote oceans and polar regions are particularly
balloon is. valuable, since weather balloons launched by meteorological services do
not consistently cover these areas. These flights traverse some of the most
Pico balloons are small, super-pressure data-sparse regions on Earth, and their primary contribution is tracking long-
balloons that carry lightweight trackers duration stratospheric air movement, with additional temperature, humidity
into the stratosphere. The stratosphere and pressure data depending on the onboard sensors.
is the second-lowest layer of Earth's
atmosphere, located directly above
the troposphere and below the
mesosphere, extending from about 10 to
50 kilometres above the Earth's surface.
It is distinguished by its dryness, lack of
weather turbulence and the presence of
the ozone layer.

These balloons can stay aloft for
months, circling the Earth multiple times.
They are typically filled with helium and
carry a payload weighing less than 20 g.
Most Pico balloons are solar-powered by
a small solar panel. Batteries would be
far too heavy, so the only disadvantage
is that they transmit data only when in
sunlight.

The Pico balloon community is
essentially building a distributed, citizen-
operated global sensor network, filling
gaps that government weather agencies
simply cannot afford to cover. Pico
balloon payloads generally consist of a
standard GPS receiver, altitude sensors
and small radio transmitters that send
data to a tracking network.

8 | EngineerIT August/September 2026