October 19, 2021

I, Science

The science magazine of Imperial College

Atlantis, the Space Shuttle, landed for the final time last week and ended thirty years of routine space flight. NASA has since been fighting to prove it’s not given up on space exploration, and that there are plenty more missions to make with new, better technology.
“The things that you’ve done will set us up for exploration of the future,” NASA Administrator Charles Bolden told the astronauts onboard the shuttle. MSL is the future of NASA’s exploration.

Last month the Mars Science Laboratory completed the first part of its mission, flying from its birthplace in California to its launch-pad in Florida. Then on Friday, NASA officially announced Gale Crater as the landing site. The race to November is hotting up for MSL when it will take its first steps on a year long flight to Mars. The launch is a bright star on the horizon for Mars scientists, representing the first leap into a new decade of space travel.

The Mission

The MSL mission goal is to determine whether the landing site and surrounding areas have ever (or still can) support life. It cannot find out whether life currently exists as it has no ability to detect fossils but it can analyse the area to see if the conditions could support life. It also aims to help prepare for human exploration by demonstrating the ability to land a very large, very heavy rover, very precisely. The Spacecraft has been designed to steer itself into landing in a similar series of moves that the astronauts landing a rocket would use, then slowly lower the rover into place by a skycrane like tether. This has made several, previously inaccessible, landing sites available by increasing the accuracy of landing by 5 times. However, the landing could still be anywhere within an area of 20 kilometers.


The Landing Site

The landing site was chosen by a crack team of scientists, as a spot that fulfills these criteria:
i) Evidence that the area may once have, or still can, support life.
ii) Meeting the safety requirements and engineering problems faced by landing a rover.
iii) Allow the rover to operate and perform its duties immediately.
Out of four options the Gale Crater was, on Friday, announced as the winner.

Map showing Gale Crater (purple) on Martian surface (NASA/JPL Image library)

The 3.5 billion year old crater is named after Walter Frederick Gale, an Australian banker who became a renowned amateur astronomer. The crater has long been topic of discussion to planetary geologists due to the layered mountain in the centre which is suspected to be clay alternating with layers of sulfur and oxygen-bearing minerals. This peak may have formed due to periods of flooding which the rover will be able to analyse. There are also several channels carved into the sides of the mound by water erosion, which would provide ideal cross-sections for the rover to analyse. The landing ellipse also contains a rock type unlike any previously seen on the red planet which is very dense and bright colored, which NASA scientists hope contains organic molecules. Inside the mountain NASA scientists hope to find complex organic minerals indicative of microbial life.

Gale Crater showing 20km landing ellipse (NASA/ JPL image library)


The Rover

NASA’s previous expedition to Mars proved a huge success, mostly down to the Spirit Rover. Spirit’s heroic contribution to the exploration of Mars is to be commemorated in a service later this year, after NASA pulled the plug on the ailing old timer on 24th May 2011. Spirit surpassed all expectations by running over five years longer than her originally intended 90 sol (1 sol = 24hr 37 minutes) expedition. She even transmitted data and collected samples despite having to drive backwards, dragging an injured front wheel in her wake!

MSL’s rover, Curiosity, is bigger, heavier and can travel further than Spirit. Although Curiosity will still retain many of their more successful features, she will also have equipment to gather samples of rock and soil and be able to distribute them directly to onboard analytical instruments. Also, unlike previous rovers, Curiosity is powered by the radioactive decay of plutonium. This means she can collect data for a full year where previous, solar powered rovers, went into hibernation during winter months and found their power supply could be disrupted in dust storms, which coasted the panels.

The rover at its testing site in Cape Canveral, Florida (NASA/JPL image library)


With missions like the Dawn spacecraft continuing to beam back images of undocumented areas of the solar system, MSL getting ready to test new landing methods on Mars and the Multi-Purpose Crew Vehicle already being designed for a manned mission to Mars, the end of the Space Shuttle program definitely doesn’t signal the end of NASA’s adventure into space.