By Dr. Kristen Miller
Faculty Member, Space Studies
According to the Oxford Language dictionary, “perseverance” means “persistence in doing something despite difficulty or delay in achieving success.” This is certainly an appropriate definition to describe the National Aeronautics and Space Administration (NASA)’s latest rover sent to explore Mars. Perseverance, which weighs in at 2260 pounds and is roughly the size of a small car, is the 5th rover NASA has landed on the surface of the red planet. Sending a robotic mission over 200 million miles away is not an easy task or a quick process, but Perseverance was worth the time and effort!
Each rover has advanced our knowledge of Mars by leaps and bounds, and each is exciting from a scientific standpoint. Some people wonder if there is anything more to be gained by sending more rovers to the red planet, especially given the considerable cost of each mission. Curiosity costs 2.5 billion dollars, for example, and Spirit and Opportunity combined cost 744 million dollars. Perseverance has a price tag of 2.7 million dollars. What makes Perseverance so special? There are several important “firsts” associated with the Perseverance mission. Here’s a quick overview of the most unique and exciting parts of this mission.
Landing Site: the first rover to actually land in an ancient Martian river delta
Perseverance is the first rover to actually land in an ancient Martian river delta, located inside the Jezero crater. A river delta does not provide a smooth landing site; Perseverance’s chosen spot represents the most challenging terrain ever targeted by NASA for a landing site, but the benefits definitely justify the risks. Orbital observations of the Jezero site have identified the presence of clays which are known to form in the presence of water. On Earth, these clays contain fossils of microbial life. In addition, the river deltas in the Jezero crater are very well preserved. They not only represent one of the most likely locations for the development of microorganisms in Mars’ wet past, but also the place where those microorganisms would be best fossilized. The Jezero crater is thus the best possibility to date for detecting signs of ancient life on Mars. It is hoped that Perseverance may discover signs of ancient microbial lifeforms on Mars – this would be the first verification of life outside Earth.
Sample Return: the first rover that will try to send a sample back to Earth for analysis
Perseverance is the first rover that will try to send a sample back to Earth for analysis. So far, our exploration of Mars has included a variety of different tests of Martian materials. However, all of these have been performed remotely by the robotic rovers. While the rovers have performed admirably, robotic analysis cannot completely emulate the observations carried out by human beings. The only opportunity scientists have to study Martian materials themselves is in the form of meteorites found on Earth, but those are contaminated by exposure to Earth’s atmosphere and environment. The opportunity to study an unaltered, pristine sample of the planet Mars is a very exciting prospect for science.
Perseverance is equipped with 43 sample tubes composed of aluminum with titanium/nickel coatings. Perseverance will fill the tubes with drill samples of the interior of Mars from a variety of locations explored during its mission. The tubes will then be launched into orbit by the Mars Ascent Vehicle, and then captured and returned to Earth, possibly even by 2031. The relay process is complicated, but well within our current technological abilities.
Sound: the first rover to record sounds on Mars and broadcast them back to Earth
Perseverance is the first rover to record sounds on Mars and broadcast them back to Earth. Other rovers have allowed us to see Mars up close and in real-time, but Perseverance is the first to add a second sense to our Mars experience: hearing. Being able to listen to Mars is more than just a novelty, though. Acoustic data can help scientists learn a lot about the Martian atmosphere. Sound depends on the temperature, density, and chemical composition of an atmosphere. Mars’ atmosphere is very different from Earth’s, and measuring sound on Mars will provide very important information about it.
Perseverance carries two microphones. One, the SuperCam microphone will listen as Perseverance fires lasers at Martian rocks in its surroundings. The noises recorded can help scientists to determine the composition of the rock itself, including rock hardness, mass, and type. This microphone will also listen to the Martian wind. It will be able to distinguish gusts and can help us learn more about the Martian atmosphere. The second microphone is listening to the sounds of the rover itself as it moves on Mars. This can help scientists diagnose the health and workings of the rover. While NASA has attempted to record sound on Mars in previous missions, this is the first time we have succeeded.
Oxygen: the first rover to create oxygen on Mars
Perseverance is the first rover to create oxygen on Mars. Perseverance carries an instrument called MOXIE, which can generate oxygen from Mars’ carbon dioxide atmosphere. Oxygen is important not only for humans but also as a source of rocket fuel. The ability to create oxygen on Mars would lessen the amount of fuel that astronauts would need to bring with them on a mission to Mars, which could result in a significant decrease in the weight of the rocket and thus the cost of the mission.
In April 2021, Perseverance completed its first successful test of the MOXIE system, creating nearly 6 grams of oxygen in under an hour. While Perseverance has only generated a very small amount of oxygen to date, the technique has the potential to be scaled up to a level that could create a more human-friendly environment on Mars and a significant supply of fuel. It represents a huge step forward towards the goal of human exploration on Mars.
Flight: the first rover to launch and fly a drone on Mars
Perseverance is the first rover to launch and fly a drone on Mars. Mars’ atmosphere is considerably thinner than Earth’s – air pressure on the surface of Mars is only 0.095 pounds per square inch (psi), compared to Earth’s, which is 14.7 psi at sea level. Drones fly by the blades pushing down on the air (this is called thrust); through Newton’s 3rd law (the law of equal and opposite forces, or action and reaction), the air exerts an equal and opposite force on the blades, lifting the drone. When the thrust exceeds the force of gravity, the drone rises; when they are equal, it hovers, and when the thrust is less than gravity the drone descends. The lower the air pressure in the atmosphere, the less air there is for the blades to push down, the smaller the thrust. The smaller the thrust, the smaller the reaction, or lift force will be, and the harder it is for the drone to fly.
On Mars, terrestrial drones will not be able to generate enough lift. The drone Perseverance carried, Ingenuity, uses special blades in order to fly. Each of its blades is made of carbon fiber and is 1.2 meters (4 ft) wide and spins 5 times faster than drones on Earth. Ingenuity has four blades total (two on top and two below); the sets spin in opposite directions to decrease the force on the fuselage. Ingenuity completed its first test flight on April 19, 2021, hovering 3 meters (10 ft) above the Martian surface for 40 seconds before gently touching down, achieving a total of 39.1 seconds of air time. As of this writing, Ingenuity has completed 5 flights, each one longer than the previous flight.
Being able to fly a drone on Mars is important because it allows us to explore a much larger portion of the planet in a much shorter timeframe compared to the slow-moving land rovers. It also gives us a bird’s eye view of the landing site and surrounding terrain, which provides valuable insights into the Martian surface. The ability to make aerial observations of the planet represents a significant advancement in planetary exploration.
Pandemic: the first rover to be launched and landed during a global pandemic
Finally, Perseverance is the first rover to be launched and landed during a global pandemic. While not a scientific goal or advancement, this marks a significant achievement for NASA and space exploration. It is truly a testament to human “perseverance” – achievement and success despite difficulty and delay!
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