Sky & Telescope - September 2022 - 12

COSMIC RELIEF by David Grinspoon
Crash as Trash
When should we start thinking about cleaning up our space
junk on Mars?
years ago to erase their tracks. Mars is
so vast, unexplored, and utterly empty
of artifacts, and our efforts are so
tentative and puny. But a few thousand
years ago, our own planet seemed so
huge compared to any of our creations
or influences that it would have seemed
silly then to think we could meaningfully
perturb or pollute it.
In a later era that I've called the
" immature Anthropocene, " we started
to significantly alter our planet but
remained ignorant of the fact that we
could. Finally, as our numbers and
influence grew, we learned that there
was no throwing things " away, " that we
inhabit a finite and mutable world.
Our maturity as a species is tied to
our recognition that we are a planetchanging
species and must learn to act
accordingly. Integrating this realization
into our global-scale activities will be at
least as essential to our long-term survival
as becoming a multi-planet species
might someday be.
We are obviously a long way from
SHARDS OF ALIEN METAL lie strewn
about the crash site of a derelict
contraption from another planet, the
remains of an intricately machined
saucer sent by a strange and distant
civilization. . . .
Ours.
In April, NASA's Ingenuity helicopter,
which is tagging along with the
Perseverance rover, returned hauntingly
surreal photographs of the rover's own
discarded " backshell, " the cover of its
entry vehicle. As the rover descended
to the Martian surface on February
18th of last year, the backshell was jettisoned
and came to rest, largely intact
but smashed around the edges, atop the
shifting red sands.
My first thought on seeing the image
above was " Cool! " It's still very hard
to fly something to Mars, and now
to finally fly something on Mars, not
to mention use it to survey our own
wreckage from the air - that is next12
SEPTEMBER 2022 * SKY & TELESCOPE
The Perseverance rover's " backshell " lies
where it fell in early 2021 on the surface of
Mars's Jezero Crater.
level cool. It's also useful: The forensics
of the crash can help us improve future
landing craft.
My second thought was " Beautiful! "
If Mars has never had life (open
question) or, as seems likely, any of its
own cultures to create art or technology,
then arguably there's something
wonderful about finally bringing these
to the planet.
But my third thought was to wonder
when we will start picking up after
ourselves. Some readers will consider it
ridiculous to ask. Others will consider
it ridiculous not to ask. They're both
right. It's just a question of time scale
and perspective.
To worry about this right now seems
silly. It's like asking the first sea creatures
that wriggled onto a shoreline of
Earth's barren continents billions of
filling up Martian craters with our
debris, bacteria, and effluence. I bet
it will be many generations before
humans live on the Red Planet in sufficient
numbers to have a self-sustaining
presence and make our mark to any
significant degree.
But at what point in the future
should we concern ourselves with this?
If we imagine that someday we'll build
cities and civilizations there, then
clearly " never " is the wrong answer.
Mars is not an escape hatch for a
ruined Earth. It could, however, serve
as a model for how we engage with a
planet from the beginning, with a longterm
plan and ourselves in the picture.
Perhaps interacting thoughtfully with
Mars, as opposed to inadvertently and
haphazardly, can even help us care for
our home world both before and after
some of us do eventually leave our comfortable
blue-and-green Earth for the
challenging lands beyond.
Ad astra cum conscientia.
¢ Astrobiologist DAVID GRINSPOON is
author of Earth in Human Hands: Shaping
Our Planet's Future.
NASA / JPL-CALTECH
Sky & Telescope - September 2022

Table of Contents for the Digital Edition of Sky & Telescope - September 2022
