Today we feature a guest post by Mona Behl, a Visiting Fellow at the American Meteorological Society. Mona provides a review of the current Mars mission, including an overview of the revolutionary instruments featured aboard the Curiosity rover.
“The fence we walked between the years did balance us serene.
It was a place half in the sky wearing the green of leaf and promising of peach.
We’d reach our hand and touch and almost touch the sky.
If we could reach and touch we said, it would teach us not to, never to, be dead.”
– Ray Bradbury, If Only We Had Been Taller
Panorama of Curiosity on the surface of the Red Planet. (Credit: NASA/JPL-Caltech/Malin Space Science Systems
November 1971 marked a major milestone in the great era of space exploration as the Mariner 9 made history by being the first spacecraft to orbit another planet. Just days before the orbiter reached Mars, Ray Bradbury gave an almost spiritual inflection to the mission with his poem, If Only We Had Been Taller.
Bradbury Landing
Sixty-two years after the publication of The Martian Chronicles, the late author’s most enduring book on science fiction came one step closer to becoming a fact. After eight years of planning and 555 million km of interplanetary travel in eight months, NASA’s most ambitious Mars exploration rover, called Curiosity, touched down inside the Gale crater on the Martian surface on 5 August 2012. Mars has a very thin atmosphere and a gravitational pull of only 38% that of Earth’s; however, even under such severe conditions, the Mars Science Laboratory (MSL) succeeded in every step of arguably the most complex landing ever attempted. In honor of the iconic writer, NASA named Curiosity’s landing site the Bradbury Landing.
Curiosity is about twice as long and five times as heavy as the Spirit and Opportunity rovers from earlier US Mars missions, and it carries over ten times their mass in scientific instruments. For the next 23 months (one Martian year), Curiosity, powered by radioactive plutonium, will roll around the red planet zapping rocks with its laser and analyzing soil by way of its onboard lab. Its mission is to search for water and look for possible signs of past life.
The Gale crater is around 6.5 km from the base of Mount Sharp, also known as Aeolis Mons, Curiosity’s eventual destination. Scientists estimate that the crater was formed by an impact roughly 3.8 billion years ago. The strata created by this impact depict layered rock formations that tell us a lot about the geological history of the planet. The layers of sediment contain different minerals that provide details of the chemistry and chemical alterations that are associated with life. Clay can be found near the bottom of the mound and, above that, layers are laced with sulfur and, even further up, by oxygen-bearing minerals. Such a layered rock formation, called an alluvian fan, is formed when water runs out of a canyon or riverbed and spreads out, scattering sediment and smaller bits of rocks. Curiosity will carefully navigate its way up the Mons, investigating the various sediment layers in order to understand the environment in which they were formed.
Unprecedented range of instruments
The rover is equipped with 17 cameras that shoot high-definition photos and video in black and white, colour, and 3-D stereo. The Mars Descent Imager, a 2-megapixel wide-angle camera mounted toward the front of Curiosity’s port side, faces the ground and has two objectives: to determine where exactly the MSL vehicle landed and to provide a geologic and engineering framework of the landing site for early operations. It came to life when the spacecraft’s heat shield jettisoned as it plunged through Mars atmosphere, firing up a rocket powered platform, lowering the rover to its landing site. An atmospheric sensor, called the MSL Entry, Descent, and Landing Instrument (MEDLI), protected the rover throughout its descent towards the Red Planet.
The equivalent of the geologist’s hand lens, sitting on the end of the rover’s robotic arm, is the Mars Hand Lens Imager. This is a self focusing, roughly 4 cm-wide camera, that will take colour images of features as small as 12.5 micrometres across, smaller than the diameter of a human hair. This camera will provide close-up images of Martian rocks and soil. Data obtained from MEDLI will be used to improve designs for future Mars-bound spacecraft.
Sitting about two metres above the surface on the rover’s main workhorse are the two mast cameras. These cameras are the left and right ‘eyes’ of the rover that can focus on objects and see details as small as a few hundred microns across.
A mobile geology lab
The bulk of Curiosity is made up of a microwave oven-sized instrument called the Sample Analysis at Mars, which is in fact a suite of three instruments – a mass spectrometer, a gas chromatograph, and a laser spectrometer – that will investigate past and present ability of Mars to support life. In addition, there are three more spectrometers called the Alpha Particle X-Ray Spectrometer, the Chemistry and Camera spectrometer, and the Chemistry and Mineralogy spectrometer. Each of these provides information and analysis of the various rocks, minerals, and chemical elements.
The rover also has two radiation hunting instruments, the Radiation Assessment Detector and the Dynamic Albedo of Neutrons. While the former instrument will measure and identify high energy radiation of all types on the Red Planet, the latter will help the rover search for ice and water-logged minerals beneath the Martian surface.
The Rover Environmental Monitoring Station, located on the neck-like mast of the rover, serves as Curiosity’s weather station. It is set to measure atmospheric pressure, humidity, wind speed and direction, air temperature, ground temperature, and ultraviolet radiation.
Since over a month, Curiosity has been sending back coloured images from the surface of the Red Planet. So far, it has also driven approximately 90 m. It has already started analyzing its surroundings by zapping a 2.5-cm wide rock called Coronation, the first rock on any extraterrestrial planet to be investigated with such a laser test. The rover is headed towards a spot called Glenelg, where three different types of terrain come together in one place. Mount Sharp, Curiosity’s eventual destination, is where the rover will carry out much of its investigation into the planet’s terrain.
On the surface of Mars, it is the journey that matters.
By Mona Behl, American Meteorological Society
