Across the sands of an infinite red desert treads one of humanity’s most ambitious scientific endeavours. It is the embodiment of innovations in engineering, which strive to uncover all that our beloved neighbouring red planet conceals: the Mars mission probes.
While there have been numerous missions to Mars, including flyby and orbiting space probes, the landers and surface rovers have provided the bulk of the information on the planet’s geochemical makeup. Within its sandy skirts, the red planet shelters several unsuccessful Soviet missions, along with two inactive American robotic-arm space probes, and its currently active Spirit and Opportunity rovers.
The first rover to successfully reach Mars was Sojourner, which travelled aboard the American Pathfinder Mission. The mission successfully landed in the valley of Ares, an area suitable for landing despite its high rock content. The mission’s intricate landing system consisted of supersonic parachutes and rockets: the impact was cushioned by large airbags, resembling an inflated ball composed of multiple smaller spherical cushions. The airbags lessened the impact by allowing the probe to bounce until it reached a complete stop. After reaching a halt, the protective airbag “petals” unsealed, allowing the rover within to land on the Martian surface.
Sojourner conducted its geological research and analysis by converting solar energy, thanks to its mounted solar panels. This method allowed the rover to reach a maximum speed of one centimetre per second. While this speed may certainly not win any Formula 1 Grand Prix, it is certainly nothing to sneeze at for a Martian rover. Considering the rocky environment in which Sojourner had to work, anything above its tortoise-like speed could have caused serious damage. As with most American landrover probes, the Sojourner outlasted its programmed mission, transmitting information for a total of three months rather than the expected two weeks.
Sojourner was followed by the robotic geologists Spirit and Opportunity, which landed on Mars in January 2004. Unlike their predecessor, which was limited to exploring distances no farther than 500 metres from the Pathfinder station, the following two missions were free to roam the Martian surface, in order to conduct extensive geological and atmospheric observations.
While this had obvious benefits, Spirit and Opportunity needed to combat unknown Martian territory, which Sojourner did not experience in the close vicinity of Pathfinder. The combination of the unfavourably sandy Martian environment and the unchartered territory resulted in the loss of manoeuvrability of Spirit in spring 2009. Since NASA could not dislodge the rover from the soft Martian soil, Spirit was converted to a stationary research platform, detecting the planet’s rotational vibration. The presence of this vibration would indicate the existence of a liquid core.
The unfavourable Martian environment also continues to pose threats to the rovers’ ability to garner the necessary energy through their solar panels. The fierce and frequent Martian dust storms impede sunlight, potentially damaging not only the panels themselves, but the rover as a whole.
The high-resolution images sent to Earth by the active twin rovers provide not only photographs of Martian terrain, but also detailed microscopic images of the rocks and soils analyzed. Similar to Sojourner’s findings, the rocks examined by Spirit and Opportunity contained high silicon content, but lacked hydrogen. Additionally, the physical characteristics of the rocks suggest that most were either remelted and recomposed, or shaped by previous floods. Moreover, bright patches of soil, which contained high levels of salt, alluded to the past presence of water on Mars.
Despite the astonishing successes of these unmanned robotic missions, future explorations may bring subsurface explorers, as well as more sophisticated space vehicles to collect and return rocks and soil to Earth. Current speculations also include the possibility of sending one-way manned mission to Mars. While such a mission would drastically reduce the overall costs, the ethical aspect has yet to be fully considered. Regardless of what the future holds, the success of the previous landrover missions has stirred a profound alacrity in planetary research, and may one day be viewed as the beginning of future planetary colonization.
Trucking away from the geological analysis of Martian rovers, next week we will look at a luminous spectacle in our first segment of Afoot Affairs. Until then, keep your eyes on the sky for November meteor showers.
