Mars Sample Return, the Bringer of Rocks
The Earth has been under constant orbital bombardment for over 4.6 billion years, as shards of space rock hit the atmosphere on a daily basis. The smaller ones burn incandescent streaks across the sky, ablating to nothing kilometers above the surface. Larger stones have enough mass to make their way to the ground more or less intact, their surfaces melted into a characteristic fusion crust. And the largest can impact with cataclysmic force and alter the course of life itself.
Most meteorites are the leftovers of solar system formation, fragments from the asteroid belt between Mars and Jupiter. However, a rare few are something else entirely: pieces of other planets and moons. Just as Earth has been subject to massive impact events, so too have its siblings. Under the right conditions an extraterrestrial explosion can blast debris beyond its parent body’s escape velocity, caroming rocks across the solar system into Earth’s orbit. The probability of such events are exceptionally low, but many unlikely things are possible given billions of years of opportunities.
Researchers have collected a few hundred meteorites that are believed to have originated from the Moon or Mars. These specimens have indescribable scientific value, as they offer the opportunity to study geology that would otherwise be nearly inaccessible. The lunar meteorites are supplemented by moonrock samples collected by astronauts during the 20th century’s longest geology field excursions, the Apollo program. However, no such samples have been deliberately recovered from Mars. Yet.
Advancing interplanetary technology will soon allow a robotic mission to collect samples on Mars and return them to Earth for study. Far more complex than any Mars mission to date, the expedition would last over five years and comprise multiple phases requiring precise coordination between robots over a hundred million kilometers from Earth. First, a lander would be launched from Earth and sent on a nearly two year journey to Mars, landing in a geologically interesting location. Concurrently, a transport craft would be launched and sent to low Mars orbit. The lander and its rover would geologize and collect samples, loading them into a small rocket on the lander. This ascent vehicle would then blast off and transfer its samples to the transport craft waiting in orbit. The transport would then spiral up out of low Mars orbit and make its way back to Earth. Once back in Earth orbit, the transport would deploy a delivery lander to get the samples down to the scientists on Earth, making history as the first objects brought back from another planet.