Curiosity might kill the cat, but it’s what keeps scientists in a career. So it’s pretty appropriate that the next generation Mars Rover, scheduled to launch on November 25th, is named Curiosity. But more importantly than its name, Curiosity is the most interesting mission to Mars since the Viking landers of the 1970s.
Don’t remember the Viking landers? OK, no problem, here’s the background.
In the late 1960s with the space race in full swing, the US was planning a suite of ambitious planetary missions. By the end of the decade engineers and scientists from the Langley Research Centre of NASA had outlined the Viking mission – an ambitious plan centered on placing landers on Mars to look for evidence of life. With numerous important scientists, such as Harold Urey and a young Carl Sagan, supporting this kind of mission the project had significant political capital. The mission parameters were not easy, the lander design was far more complex than lunar landers NASA had designed previously.
But to cut an incredibly interesting story short, the Viking landers were one the most successful missions flown by NASA in the 1970s. Aside from their experiments (more on that in a sec) they sent back images from the Martian surface. I remember thinking as a six year old, “WOW! These are the first pictures from another planet!” Actually that wasn’t true because the Russian’s had images of the Venusian surface, but I didn’t know that at the time. As far as I’m concerned those first images were just as good as the ones taken by Spirit and Opportunity almost 30 years later, and heck, the Vikings were the first landers to show us frost on another planet!
But for all the amazing images, it was the science experiments that really excited me. The landers were designed to scoop up soil and then test it for signs of alien life! That isn’t as easy as it sounds. There isn’t any one single chemical or biological test that can be done to look for life. So the Vikings carried a suite of four experiments. One to examine the chemical compounds present (after baking the sample) and three others to look for signs of biological processes: photosynthesis, metabolism and respiration. Despite some really interesting preliminary results, it turns out that Mars didn’t have any signs of life in these tests. Although 40 years later, the data remain under scrutiny and there is an outside possibility that something was missed. So Mars still has plenty of secrets to be unlocked….
Enter Curiosity. With a scientific payload weighing ten times that carried by any other rover, and being a similar size and weight to a Mini-Cooper, it will bring Mars science truly into the 21st century. Unlike the Viking landers, Curiosity’s mission profile is best described as assessing whether the right conditions for life could have existed on Mars, rather than looking for life directly. But it will revisit one of the Viking tests: do the chemical compounds in samples include organic (carbon including) compounds that are necessary for life? In an advance over the Viking missions it will also do it in two ways, the first being similar to the Viking approach of testing a baked sample, while the other approach will use liquids in the analysis. Many scientists believe the liquid method will in fact find the organic molecules that the baking method essentially destroys.
But these chemical tests are just one part of Curiosity’s 2-year mission (actually 1 Martian year of 686 Earth days, or 668 Martian “sols”). Curiosity (or Mars Science Laboratory as it was originally known) will also examine Martian geology and atmosphere, while sending back the first high definition movies of the Martian surface. Nothing quite beats a high-def movie for giving a feeling of being there, and NASA isn’t missing a trick on this one – it will be incredible! Over the next few days I’ll outline the scientific payloads.
For all the excitement, one thing makes Curiosity just a little bit scary – its landing. At close to one ton in weight, it can’t just be dropped on a parachute – the gravitational field of Mars is too strong. So a deft powered descent is part of the mission profile. Anyone who recalls the Moon landings knows that finding the right place to land can be pretty difficult (Apollo 11 got perilously close to running out of fuel while Neil Armstrong found the right place to land). To solve this problem Curiosity will actually be lowered by crane from a hovering descender onto one of the smoothest pieces of Martain soil we know. This will be the first time a “sky crane” has been used in any mission.
And Canada’s involved too! The Alpha Particle X-ray Spectrometer (APXS) was funded by the Canadian Space Agency and will allow Curiosity to determine the elements in a sample by shining a beam of alpha particles on the target. The APXS science team includes members from The University of Guelph and the University of New Brunswick.
If you haven’t guessed already, I can’t wait for Curosity to begin its journey. It will take over 8 months to get there, but the science it will produce is the most exciting event on Mars in almost 40 years. And it has a face for fame, anyone remember Johnny 5 from “Short Circuit”? Separated at birth?