NEW SPACE EYES FOR CANADA
O
N JUNE 12, 2019, a SpaceX Falcon 9 rocket blasted off from Vandenberg Air Force
Base, in California, carrying three identical 1,400-kilogram RADARSAT Constel-
lation Mission (RCM) satellites, the Canadian Space Agency’s new generation of Earth-
observation orbiters. Employing radar to bounce signals off the Earth’s surface, the
satellites can generate images regardless of the weather conditions below.
A trio of coorbiting RADARSAT satellites makes it possible to image the exact same
view of the exact same location on the Earth’s surface once every four days instead of once
every 24 days, as is the case with RADARSAT-2 (launched in 2007 and still operational).
This ability to frequently revisit a specific spot allows the creation of composite images
that can highlight changes over time in any particular area. The RCM’s versatility is
especially useful for tracking sea ice and oil pollution, monitoring agriculture, wetlands,
forestry and coastal changes and assisting disaster management. And with four passes per
day across Canada’s Far North, plus several daily passes over portions of the Northwest
Passage, the RCM satellites are able to monitor the Canadian Arctic as never before.W
HAT’S BIG, red and a long-lived
iconic planetary feature that might
be gone in the near future? The answer is
Jupiter’s Great Red Spot (GRS), a swirling
mass of coloured clouds higher and cooler
than the Jovian clouds surrounding it—and
big enough to easily hold planet Earth. The
famous spot may have been initially observed
in the mid-1600s by several keen planet
watchers, including Jean-Dominique Cassini
of the Paris Observatory, but the first official
record of it is a drawing made by German as-
tronomer Samuel Heinrich Schwabe in 1831.
Curiously, the spot has been mostly shrinking
over the past century, and nobody is sure
about the storm’s future. “Storms are dynamic,
and that’s what we see with the Great Red
Spot,” says Amy Simon, an expert in plan -
etary atmospheres with NASA’s Goddard
Space Flight Center. “It’s constantly changing
in size and shape, and its winds shift as well.”
The GRS is sandwiched between two
conveyor belts of cloud: the South Equato-
rial Belt (SEB) and the South Tropical Zone
(STrZ). According to Glenn Orton of the
Jet Propulsion Laboratory, the spot has
been stable for so long because it’s wedged
between these two jet streams moving in
opposite directions, which keeps feeding
energy into the GRS vortex.
But something has changed. The SEB is
now dragging material away from the Red
Spot, creating long strands of reddish cloud
that eventually merge into the SEB. John
Rogers of the British Astronomical Asso -
ciation noted in a Jupiter report in May:
“There has been much interest in the emer-
gence of red methane-bright ‘flakes’ or
‘blades’ detaching from the [west] end ofthe GRS—a phenomenon that has been
prominent in recent JunoCam images and
also observable in amateur images.”
Is the GRS on a path to oblivion? No one
knows. The historical record indicates its
total area grew temporarily in the 1920s.
“There is evidence in the archived observa-
tions that the Great Red Spot has grown
and shrunk over time,” explains Reta Beebe
of New Mexico State University. “However,
the storm is quite small now, and it’s been a
long time since it last grew.”6 SKYNEWS •SEPTEMBER/OCTOBER 2019
A SERIOUS CASE
OF SHRINKAGE
SKY NEWS BRIEFS by PAUL DEANS
THREE EYES OVER CANADAThis illustration depicts the three new RADARSAT satellites
that are evenly spaced along the same orbital plane at an altitude of 600 kilometres.
ILLUSTRATION COURTESY CANADIAN SPACE AGENCYNOT SO GREAT ANYMORE Even allowing for the different image quality and viewing angles
of Jupiter’s Great Red Spot, as seen by Pioneer 11 in 1974 (left) and imaged by Damian Peach on
April 13, 2019 (right), the decline of the giant planet’s Red Spot over 45 years is clearly evident.
LEFT: COURTESY NASA. RIGHT: COURTESY DAMIAN PEACH