We’re Going on a Trip!

NASA’s Perseverance rover, or Percy to its friends (@PercyRover), is the latest robot to be sent to Mars. Its primary objectives are to look for habitability, seek biosignatures, cache samples, and prepare for humans.

Wait…did you say prepare for humans? If you are anything like me you just lost your whole mind. That’s nuts! We’re getting ready for humans on Mars! Well…..kinda. Like most science, it’s complicated. So, as my favorite audio medic Lúcio Correia dos Santos would say, let’s break it down.

Looking for Habitability: The first objective for Percy is all about geology. Percy will be landing around the lovely Jezero Crater, a once flowing delta with some super neat dirt. Why is dirt important? Well, anyone that has tried to grow a plant can tell you that the minerals in soil are important for a successful garden or leafy friend. The composition of the soil can tell scientists if life was once present on the red planet. Since the discovery of water on Mars, scientists have been interested in studying what flowing water on Mars would have looked like and how it would have impacted the environment. This ties nicely into our second point…

Seeking Biosignatures: Alright, now we are getting into astrobiology (a.k.a. space life!) First the bad news; Percy is not looking for any presently living things. Sorry, no aliens. Instead, Percy is looking for signs of ancient life. Scientists are confident that the planet once sustained habitable conditions but have yet to find any evidence that living things were on the planet. Percy is designed with a variety of instruments that will be used to collect various samples to be studied in depth at a later date. That’s right, NASA and the European Space Agency are teaming up on the Mars Sample Return mission which would see samples collected by Percy returned to Earth in 2028 with the help of a new rover and rocket system. This is significant because scientists can’t get every piece of equipment they want on a rover, so their ability to analyze samples is limited. Being able to spend all the time and energy they want on these samples once they reach Earth would allow for more specialized analysis.

Caching Samples: So what kinds of samples is Percy looking for? For Percy this part of the mission is all about finding “Compelling Rocks.” What makes a rock compelling? This all ties into that idea of astrobiology. Geologists, astrobiologists, and a variety of other experts select sample sites based on how likely they are to tell us about life and the living conditions on Mars 3.6 billion years ago. These include rocks that may have been shaped by environmental factors that support life, like rivers and streams or that may contain traces of ancient life. Other samples will focus on volcanic rock and other geologically significant rocks that can help paint a picture of the timeline of the planet. While it may not sound immediately interesting, these samples will help humans get a better idea of what changes occurred over time scales of millions of years. Once these samples are collected, Percy will drop them off at a pick up site for future rovers to come and collect.

Preparing for Humans: There are three primary parts of this objective and they all have fun acronyms for the instruments that are being used. The first one sounds like your favorite 1876 health vitality drink: it’s MOXIE. MOXIE (Mars OXygen ISRU Experiment) is a device that converts carbon dioxide into oxygen, like a tree. The device will test to see if oxygen can be produced using the carbon dioxide found in the planet’s atmosphere. This would provide future martian explorers air to breath as well as a propellant that can be used to move around the planet. The second instrument is MEDA (Mars Environmental Dynamics Analyzer.) This device is designed to test the temperature, humidity, and wind on Mars by sampling the dust in the air. By sampling the dust, scientists can get a better idea of what the weather on Mars is like and what conditions future explorers may face. The third instrument is the master detective himself, SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals) and it’s very own WATSON (Wide Angle Topographic Sensor for Operations and eNgineering). WATSON is designed to look for signs of biosignatures that can tell scientists about life on the red planet. It also contains samples of space suits that can be tested to see how they stand up to the martian environment.

Now, with a 7-month road trip, two things are important: snacks and friends. Percy doesn’t have much need for the former but it does have the latter: Ginny, the first helicopter to fly on another planet. It’s an amazing feat that would not only melt the brain of Paul Cornu, the inventor of the helicopter, but it also serves a unique scientific role. While Ingenuity (Ginny for short, @GinnyHelicopter) doesn’t have any scientific instruments of its own, it is a test to see if future aerial research is possible on our smaller red neighbor. Aerial research provides some huge benefits over ground transportation. First off, having an aerial perspective would allow scientists to get a clearer picture of the geology on Mars and investigate regions that are too treacherous for traditional rovers to explore. Secondly, aircraft tend to be faster at moving around and could be used to collect samples or carry materials for scientific investigation. Finally, in the future, Mars helicopters could transport supplies between sites, allowing for greater mission flexibility and the sending of catty messages to other rovers.

So besides being the FIRST SPACE HELICOPTER, what makes Ginny special? Why don’t we just pack an apache helicopter in a cannon and shoot it at Mars? 1) that’s a bad idea. 2) Ginny has been tested in a variety of different simulations to make sure that it has the best chance of a successful launch. Mars is smaller and lighter than Earth, resulting in a gravity field of around 37% of the Earth’s. What does this mean? Well, if you weigh 200lbs (~91kg) on earth you would only weigh 74lbs ( 33kgs) on Mars. (Yeah, yeah, I know that technically kilos are a measurement of mass and are not impacted by gravity, but it’s also how most people understand weight if they use the metric system. So no going off in the comments section!)

Anyway, back to the FIRST SPACE HELICOPTER. This is all great news for liftoff, it’s a lot easier to fly when you’re not fighting gravity as much. However, there is a massive downside to martian aviation: the atmosphere. Mars doesn’t have a robust atmosphere, meaning that the density of “air” on the planet is only 1% of the air density on Earth. This means that when the blades on Ginny are spinning there isn’t as much stuff to push down on to get it up into the air and stay there. In order to work around this, Scientists have made sure that Ginny is super light and has massive blades for its size to make sure it can generate enough lift.

But Ginny isn’t just strong, it’s wicked smart. If you have ever flown a remote control drone or helicopter, you know that they are really finicky. A single bad touch can result in a crash landing. What makes matters worse is that radio signals are not instantaneous; the universal speed limit makes things difficult. All information, including radio waves, can only travel as fast as the speed of light, ~3×10^8 m/s (or “wicked fast” in imperial.) So a controller input from Earth would take around 3 minutes to reach our friendly helicopter. Imagine trying to control a drone with a 3-minute delay! NASA’s computer scientists programmed Ginny with AI to be able to control its own flight path as well as manage its temperature, charge its batteries using solar cells, and land. Supposedly. This is all highly tested but it’s never been done before so we will have to see how this first flight goes!

There are a lot of different and exciting components to this Mars rover and it’s high flying pal. Percy and Ginny are two amazing feats of human creativity and scientific achievement but they are not alone. There are many other missions currently underway. Two stand outs satellites are the al-Amal or Hope, a UAE mission that’s scientific team is notably made up of 80% women, and Tianwen-1, China’s first martian satellite. Percy is set to touch down on February 18th with Mission control starting it’s broadcast at 11:15 a.m. PST / 2:15 p.m. EST / 19:15 UTC. If you are interested in celebrating the landing or just want to know more you can look through the coloring sheets and other goodies in NASA’s Virtual Landing Packet.