On the 6th of August, just a few days away, a new chapter in the history of space exploration will open. NASA’s latest and greatest exploration vehicle, a massive automated rover, is scheduled to touch down on Mar’s surface to begin a year-and-a-half long mission of discovery and insight. The characteristics of this rover, it’s exceptionally challenging journey to the surface of Mars, and the lofty goals of it’s mission make it a mission you should know about, and be really excited about.
We have had a long history of fascination with the rusty, red planet of Mars. It’s now believed by astronomers and scientists that Mars once had a considerable atmosphere, and oceans of liquid water. A question constantly on the minds of astronomers is whether Mar’s once possessed conditions suitable for life, and, more importantly, whether life ever developed on Mars as it did here on Earth. Understanding the significance of Mars and the potential for discovery there, NASA has also had a history with the planet. The United States has sent a number of orbital probes to survey its surface and composition and a series of rovers to analyze it from the ground. As I type this, one of those rovers, Opportunity, is still beaming back images and information to Earth.
Curiosity, as the new rover en route is named, is almost twice as long as those previous rovers and five times as heavy. Its mission to Mars has four official scientific goals: to determine whether Mars ever supported life, to study the geology of Mars, to study the Martian climate, and to plan for a future human mission to Mars. To accomplish this, it carries a huge suite of instrumentation, almost ten times as much in weight as the other rovers. These include a number of cameras, radiation sensors, X-Ray spectrometers, chemical-sensing instruments, and ground sample analysis instruments. Curiosity is, by far, the most complicated and sophisticated machine ever sent into space.
Getting Curiosity onto Mars, however, will not be easy. While the other rovers descended straight through the thin Martian atmosphere and crash-landed on the surface protected by massive airbags, the size and weight of Curiosity made that option impossible. Instead, scientists developed a new way to deliver the rover to the planet’s surface: a ‘high-precision entry, descent, and landing’ system. It works as follows:
As the capsule carrying Curiosity enters the Martian atmosphere, it will attempt to bleed off speed. The Martian atmosphere is very thin, so the capsule must spend quite some time flying in an angle through it to reach a suitable descent speed. Once that speed has been achieved, a massive parachute will deploy from the capsule to brake the capsule. This parachute can, and will, be opened at supersonic speeds, and is to date the largest and strongest parachute used by a spacecraft. After the rover has been slowed by the parachute, it begins the most complicated and novel part of it’s descent. The capsule surrounding the rover detaches, and the rover and an attached ‘descent’ stage fall towards Mars. This descent stage can be thought of as a jet-pack covering the rover: once it senses the ground below it, it will ignite a series of rockets underneath it to slow its fall. These rockets enable precision targeting for the landing location, and can bring the rover down close to the surface through a gentle glide. Curiosity is now slowly dropped released from the descent stage by a large ‘crane’ onto the surface of Mars, and once it has touched down and detaches from the crane, the descent stage’s rockets blast it off towards the horizon to crash somewhere away from the rover.
The hope is that this new approach will enable Curiosity to be gently landed on Mars at its intended landing zone with extreme precision. This landing zone is within the Aeolis Palus region of the Gale Crater, a choice which astronomers determined was ideal for the mission that Curiosity intends to carry out. However, this new landing approach has never been attempted before, and the risks of failure run high. Every system must work in perfect order for the rover to safely and accurately get to Mar’s surface. The highly-computerized and autonomous nature of this descent means that the rover’s computer must calculate the landing, sense the ground beneath it, plot trajectories for the landing zone, and land essentially land itself. The time it takes for it to send information back to Earth about its landing, and then receive the information from Earth sent back to it, is longer than the actual descent itself… by the time mission control hears that Curiosity has hit the Martian atmosphere and is beginning its landing, it will be on the surface, either dead or alive.
The tricky landing might seem like a gamble, but NASA is confident in the capabilities of its planning and its rover. Indeed, if they pull it off, the Curiosity landing will no doubt go down as the most complicated, sophisticated, and technologically impressive mission of exploration to date. This mission will be one of the finest in the exploration of Mars, and could provide insights and discoveries about the planet which dwarf anything discovered by the rovers of the past. It’s something which those of us with interest in the planets and space exploration should be sitting at the edge of chairs in excitement for, and something which everyone should pay attention to. It is the work of some of our country’s finest and brightest scientific minds.
Here is a video, published by the designers of the Curiosity rover, detailing and providing visualization of the complicated landing: