Hey there!

NASA's Perseverance Mars rover is set to land on the red planet this Thursday, February 18th, only two days away! I decided the event deserved its own special edition of Explore and Observe, so I hope you enjoy this message and are able to learn a bit more about what to expect from the landing, overall objectives, and mission operations. Have a great week, and make sure to tune in on Thursday! 

- Evan

#01 HOW TO WATCH

+ Simply tune in to NASA's live broadcast of the landing. Coverage starts on Thursday the 18th at 11:15am PST / 2:15pm EST with the actual landing around 12:55pm PST / 3:55pm EST. Make sure to logon at least 10 minutes ahead of time to catch all the landing action. It'll take 7 minutes or so for Perseverance to go from outside Mars's atmosphere to safely on the ground and you don't want to miss it!

#02 ENTRY, DESCENT, LANDING

+ You'll hear the acronym EDL a bunch during the broadcast. That stands for Entry, Descent, and Landing, and basically refers to all the stuff that needs to happen for Perseverance to reach the surface safely. Mars is a uniquely challenging place to land since it has enough atmosphere to be inconvenient, but not enough to actually slow a spacecraft down to a safe speed. Perseverance's landing sequence involves a number of steps that make use of a heat shield, a supersonic parachute, a rocket-powered jet pack, and a maneuver called the "skycrane." Here's a great video that explains everything.

+ Note that it takes a radio signal 11 minutes to travel from Earth to Mars at their current distance, so the entire landing is done autonomously by the rover. That also means that by the time we get a signal indicating Perseverance has touched the upper atmosphere, it will actually already be alive or dead on the surface!

#03 WHAT HAPPENS NEXT?

+ After Perseverance is on Mars the mission will enter a commissioning phase lasting a few weeks. During this time, the engineering team will verify that all systems are operating properly and there's no damage to the rover. Afterward, the rover will drive away from the landing site and start doing science on Mars!

#04 SAMPLE RETURN

+ Perseverance is the first step in a Mars sample return campaign, and a significant percentage of mission resources are directed towards this goal. A drill on the end of the robot arm will collect rock samples (cylinders about the size of one of your fingers to be specific). The samples will then be stored in hermetically sealed metal containers using a sample caching system. This caching system takes up about the front third of the rover body and is probably the most complicated mechanism ever flown into space.

+ If everything goes well, the samples will be left on the surface of Mars, collected by another mission later this decade, and eventually launched back to Earth around 2031. Once here, scientists will be able to unleash an entire arsenal of laboratory equipment on the samples and learn more than we could ever hope to do with just a rover. On the flip side, if any part of the Perseverance mission fails, it puts the entire decade long sample return campaign into jeopardy. No pressure!

#05 SCIENCE!

Perseverance carries a full suite of scientific instruments in addition to the sampling system. Here's an overview of the main components:

+ SHERLOC and WATSON are on the end of Perseverance's robot arm. SHERLOC will use a scientific analysis method called spectroscopy to figure out what sorts of minerals and organic molecules are present in rocks down to sand grain-sized details. WATSON is basically a camera combined with a magnifying glass that will provide visual images of the same rocks studied by SHERLOC.

+ PIXL is also on the end of the robot arm and uses a different method involving X-rays to identify chemical elements. 

+ MOXIE is bolted to the body of the rover and will attempt to extract oxygen from the carbon dioxide in Mars's atmosphere. This is a very useful thing to know how to do if you ever want to send people to Mars.

 + SuperCam is located on the mast, or head, of the rover. It pairs a laser capable of zapping rocks with a telescopic imaging system to allow scientists to study the composition of rocks that are up to 20 feet from the rover.

+ RIMFAX is the first ground-penetrating radar sent to Mars and will be able to study subsurface structures up to 30 feet underground.

+ MEDA is the rover's weather station and will collect information like wind speed, temperature, humidity.

#06 INGENUITY

+ A helicopter named Ingenuity is stowed away in the belly of the rover. At some point in the first couple of months of the mission, Perseverance will lower the helicopter to the ground so it can perform a few flights. The helicopter is considered a "technology demonstration" meaning that its purpose is to prove a concept and it will likely only be flown a few times. Ingenuity doesn't carry any instruments other than a camera but could be a precursor to more capable helicopters on Mars in the future. 

#07 CAMERAS

+ Perseverance is loaded with amazing cameras that will allow us to see Mars better than ever befor.

+ Four separate cameras will provide a first-person view of EDL including parachute inflation and rover touchdown. Don't expect to see those videos right away though. It'll take time to downlink all the data to Earth. 

+ MastCam-Z constitutes a pair of cameras on the mast that can take color images, make videos, zoom in and out, and work together to make 3D images.

+ The NavCams are used for driving the rover and are also on the mast. They provide wide-field 3D images useful for planning routes and avoiding obstacles.

+ HazCams are mounted low on the very front and rear of the rover to keep an eye out for hazards.

#08 MOBILITY

+ The rover operators will have a number of options to choose from when it comes to driving the rover, making trades between speed and safety depending on the terrain. Upgrades made to the software will allow Perseverance to drive twice as fast as its predecessor, Curiosity.

+ The wheels on Perseverance were also upgraded since Curiosity saw more wheel wear than expected. Perseverance's wheels are a bit thicker and have a different tread pattern to prevent a similar issue.

#09 POWER

+ Perseverance is powered by a hunk of plutonium in the rear of the rover. The system works by converting the constant thermal energy generated by the plutonium into electrical energy. It generates about 100 watts of power, only about as much as a lightbulb! Power is stored in batteries and rationed for higher energy activities like driving or drilling.

#10 COMMUNICATIONS

+ Communication to/from Perseverance can be done through one of three different antennas. There's the high gain antenna which has a large data rate but must be pointed directly at Earth to work, an ultra-high frequency antenna that can talk to satellites in orbit, and a low gain antenna which is omnidirectional but has a very low data rate and is used generally used only in emergencies.

That's all for this edition. I hope this e-mail provided some more context around the mission and you have a good idea of what to expect from landing. Explore and Observe will return to the normal fortnightly email cadence this weekend. A reminder that you can respond to this email to tell me about anything you liked or didn't like, tell me about a project you're working on, or suggest a story. You might also forward this email to a friend so they can subscribe too!

- Evan Hilgemann

This newsletter was produced as a private venture and not in the author's capacity as an employee of the Jet Propulsion Laboratory/California Institute of Technology or of Griffith Observatory. Any views and opinions expressed herein or on exploreandobserve.com are his own and not those of his employers.

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