On Earth, evidence of past human civilization and habitation can be gleaned from the rocks, soil and some still-standing monuments of architecture large and small, but the effects over time of weathering and over longer periods of the geologic cycle tend to erode, erase and eradicate those past efforts.
But as a space-faring culture, we have now left our marks across the solar system on planets, moons, asteroids and in the empty space between them. Some of these “marks” are yet-functioning robotic spacecraft. Some are litter, scattered about the place like so many discarded soda cans, plastic grocery bags, depleted batteries and defunct electronic devices.
Are we trashing our solar system? Well, on the big scale of things, not much — and at present unavoidably. It’s a big solar system and the number of expended rockets, ejected parachutes, crumpled heat shields, empty fuel tanks and just plain expired or lost robots is quite small. And there’s no economically feasible means at present to clean them up. Besides, whose backyard are they littering?
As our surveillance of the reaches of our solar system grows more sophisticated, we are beginning to run across bits of “junk”. Don’t get me wrong, these are once important and highly useful equipment of exploration that we’ve left behind over the years.
Recently, the discerning eye on NASA’s Mars Reconnaissance Orbiter (the HiRISE camera) has spotted a couple bits of extra-Terran detritus.
Check this out: the discarded parachute of the Curiosity lander, flapping in the Martian breeze. I wondered where that ended up!
And how about this Antiques Skyshow find: The possible last resting place of one of the first robots to land on Mars, the Soviet Mars 3 lander?
Some day in the future, when travel about the solar system is a routine vacationing activity, some of the sightseeing historical points of interest may be today’s space junk. I can imagine raised walkways and interpretive signs encircling the dust and wind scoured remains the long lost Beagle II lander on Mars, or the descent module of the Apollo 11 spacecraft on the Moon, or the Huygens lander half sunken in the super-frigid methane muds of Titan or the thoroughly scorched hulk of a Soviet Venera lander on Venus.
And imagine the Voyager and Pioneer spacecraft, coasting outward into interstellar space, one day serving as archaeological finds by alien species living in distant star systems, in the distant future, telling them that we are here—at least, were here, anyway.