Sky & Telescope - February 2024 - 9

ASTRONOMY & SOCIETY
A New Hope? Taming the
Satellite Swarm
ONE MILLION SATELLITES and counting.
This is the future, according to
filings with the International Telecommunication
Union (ITU). The question
is, how many of these satellites-to-be
will become reality?
The ITU filings, which detail how
many satellites will go up, which orbits
they will occupy, and what frequencies
they will use for operations, have skyrocketed
in recent years. Some member
states have filed for tens or even
hundreds of thousands of satellites. At
least some of this paperwork is almost
certainly speculative, similar in concept
to the land speculation that occurred
back in the " Wild West " - but this
time in space.
In the October 12th Science, political
scientist Andrew Falle (University
of British Columbia, Canada) and
colleagues suggest this situation may
provide an opportunity: " The ITU filings
are the warning, and also part of the
solution, " they write.
On November 20th, representatives
from governments and industries
around the world come together for the
World Radiocommunication Conferat
the same solar longitude, and their
apsidal lines (the line passing through
perihelion, the Sun, and aphelion) were
also nearly coincident.
This orbital clustering is a telltale
sign that a single event occurred in the
solar system's youth - more than 4 billion
years ago - that put the Sednoids
onto their present paths. Nothing has
disturbed the slow evolution of those
orbits since.
Huang's work showed that the
culprit could have been a primordial
planet that was ejected from the solar
system only 100 million years after its
formation. Other explanations - such
as a star from the Sun's birth cluster
passing close by - are also plausible, but
calculations haven't yet borne them out.
More work is needed on those scenarios.
ence to review and revise rules for the
ITU. In addition to proposals already on
the table, Falle and team suggest that
the ITU might also limit the number of
satellites in individual constellations/
orbits and/or require higher fees or
similar consequences for large filings.
" The rules would mostly help us
understand how big the problem is
going to be, but that's important, " says
Jonathan McDowell (Center for Astrophysics,
Harvard & Smithsonian). " It's
hard to know how to prepare mitigation
strategies when the number of satellites
that are really going to go up is uncertain
by a factor of 10 or more. "
Regardless of what happens at the
WRC, low-Earth orbit remains premium
real estate. In addition to Starlink's
4,968 satellites and OneWeb's 634
satellites (those numbers accurate as of
press time), Amazon just launched two
prototypes for its planned 3,236-satellite
Project Kuiper. Other projects
are underway, too. It's possible new
ITU rules may stem this coming tide;
the main advantage for astronomers,
though, will be simply knowing the size
of the beast they're dealing with.
¢MONICA YOUNG
Read further details on the filings submitted
so far as well as proposed rule
changes at https://is.gd/ITUfilings.
IN BRIEF
Found: Castaway Stars
After decades of searching, scientists have
found 13 stars accompanying the Magellanic
Stream, a giant ribbon of gas discovered
more than 50 years ago. Drawn from
the Large and Small Magellanic Clouds, a
pair of dwarf galaxies currently falling into
the Milky Way, the gaseous stream stretches
over three-quarters of the sky. Vedant
Chandra (Center for Astrophysics, Harvard
& Smithsonian) and colleagues were taking
spectra of more than 200 stars at the Milky
Way's outskirts using the 6.5-meter Baade
Telescope at Las Campanas Observatory
in Chile when they discovered 13 stars that
followed the same motion as the stream's
gas; the chemical signatures are consistent,
too. The astronomers also used their
observations to trace the stars' trajectories
back to the Clouds. The researchers
presented their findings in the October
20th Astrophysical Journal. " We've been
looking for so long, like since the 1980s,
to try and find these stars, " says Gurtina
Besla (University of Arizona), who wasn't
involved in the study. " That there's now
pretty convincing evidence that the stars
exist is just exciting. "
¢KATYA GOZMAN
pAn artist's concept of Sedna, a small world in
the outer solar system
If the " early planet " hypothesis is
true, then any new Sednoids ought to
share the same orbital characteristics.
Astronomers surveying the sky for more
distant solar system worlds may find out
that Planet X has left the building.
¢EMILY LAKDAWALLA
Psyche Launches for
Metal Asteroid
NASA's Psyche mission launched successfully
atop a SpaceX Falcon Heavy
rocket on October 13, 2023, before placing
Psyche on course for its first planetary
encounter, with Mars in May 2026. Before
the mission zooms past the Red Planet,
Psyche will use xenon fuel accelerated
through ion engines to widen its orbit
around the Sun. The Mars swingby will
then send the spacecraft onward to the
target asteroid, also named Psyche. Final
approach to the metallic asteroid will
begin in May 2029, and following gravitational
capture in July 2029, two years of
observations will commence. Cameras on
the spacecraft will map the asteroid's surface.
Other instruments onboard include
gamma-ray and neutron spectrometers as
well a magnetometer. The mission will also
conduct radio science to peek inside the
rock's interior. Once Psyche's images start
arriving on Earth, they will immediately
be posted to a public website: https://
science.nasa.gov/mission/psyche/multimedia-raw-images/
¢EMILY
LAKDAWALLA
sk yand tele scope .o r g * FEBRUARY 2024
9
NASA / JPL-CALTECH
https://www.is.gd/ITUfilings https://science.nasa.gov/mission/psyche/multimedia-raw-images/ https://science.nasa.gov/mission/psyche/multimedia-raw-images/ https://science.nasa.gov/mission/psyche/multimedia-raw-images/ http://skyandtelescope.org
Sky & Telescope - February 2024

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