Sky & Telescope - September 2019 - 9

SPACE

STA RLINK SATELLITES: SPACE X; JUPITER: CLY DE FOSTER

SpaceX Launches 60 Starlink Satellites
ON MAY 23RD SpaceX launched 60
satellites as part of its Starlink constellation, which aims to bring high-speed,
broadband internet to locations across
the planet. This is only the ﬁrst volley
of nearly 12,000 satellites planned for
launch over the next decade.
Skywatchers and professional
astronomers alike have expressed concerns about the detrimental effect on
the night sky. In the satellites' initial
orbit, they ranged in brightness from
1st to 3rd magnitude - easily visible to
the unaided eye - and made a neat line
about 7° long. The satellites are still
climbing to an operational altitude of
550 km (340 miles), fading to magnitudes 3 to 6 as they go.

Six launches of 60 satellites will be
needed to activate the system; after 24
launches, the constellation would provide global coverage. If all goes according to plan, SpaceX will launch satellite
fusillades multiple times per year over
about nine years. So the incredible sight
that awaited skygazers in May could
repeat two to six times in 2019 alone.
To ﬁnd satellite passes for your location,
visit Heavens-Above.com.
The long-term plan for Starlink calls
for nearly 12,000 satellites in multiple
orbital planes, a number that includes
1,584 satellites at an altitude of 550
km and 7,518 at an even lower altitude of 340 km. Satellites in such low
orbits could remain bright and visible

near-infrared wavelengths, especially
around 890 nanometers. Methane
absorbs light at this wavelength, so
methane-rich features such as belts
and zones appear dark. However,
strong winds clear out methane from
the GRS, and the storm appears bright
at this wavelength instead.
Visually, however, the GRS and its
castoffs may be easier to see through
a blue ﬁ lter, where they appear darker
than their surroundings.
Flakes from the GRS are common
now but were only rarely seen before

2018. The May event also appears
to have been more pronounced than
those seen in the past. Observers
are urged to monitor any continued
changes in the GRS and SEB and share
their observations with the British
Astronomical Association (BAA) or
the Association of Lunar and Planetary Observers (ALPO).

p Ultimately, SpaceX wants to place nearly
12,000 Starlink satellites in orbit, a plan that includes 1,584 at an altitude of 550 km and 7,518
at an even lower altitude of 340 km.

after twilight, though it's still unclear
how bright they'll be. A statement by
the Large Synoptic Survey Telescope
called the satellites' potential effects "a
nuisance rather than a real problem."
Meanwhile, the National Science Foundation and National Radio Astronomy
Observatory have also issued statements, saying they are working with
SpaceX to manage the use of particular
radio bands. As other companies are
planning to compete with SpaceX, additional negotiations may be needed.
■ BOB KING

South
Equatorial
Belt

■ SEAN WALKER
u The swirl that connects the Great Red
Spot to the South Equatorial Belt contains
material drawn from the long-lived storm.
North is up.

sk yandtele scope.com * S E P TE M B E R 2 019

http://www.heavens-above.com http://www.skyandtelescope.com

Sky & Telescope - September 2019

Table of Contents for the Digital Edition of Sky & Telescope - September 2019