Perseverance Mission landing

Source: NASA/JPL-Caltech

  This week - on 18 February 2021 - NASA's Perseverance Rover  landed on Mars safely. There is so much information about this mission from many different sources that it is difficult to choose what to focus on with engineering students.

  For my students, I chose materials from NASA's own website for the mission, which has further links to different asepcts of the mission and to information about Mars. The most attention-getting part is the video of the Perseverance landing, which was recorded by several high-definition cameras located under the spacecraft. 

The video last 3:25 minutes; English subtitles of the audio embedded in the video are available.

Link to video: https://www.nasa.gov/press-release/nasa-s-mars-perseverance-rover-provides-front-row-seat-to-landing-first-audio

As indicated in the accompanying text, Thomas Zurbuchen, NASA associate administrator for science, says, "This video of Perseverance's descent is the closest you can get to landing on Mars without putting on a pressure suit." He goes on to say, "It should become mandatory viewing for young women and men who not only want to explore other worlds and build the spacecraft that will take them there, but also want to be part of the diverse teams achieving all the audacious goals in our future."

The link to the pages about the Perseverance mission: https://www.nasa.gov/perseverance

The website describes the landing and its challenges in a very clear way:

• "Entry, Descent, and Landing - often referred to as 'EDL' - is the shortest and most intense phase of the Mars 2020 mission. It begins when the spacecraft reaches the top of the Martian atmosphere, travelling nearly 12,500 miles per hour (20,000 kilometers per hour). It ends about seven minutes later, with Perseverance stationary on the Martian surface. To safely go from those speeds down to zero, in that short amount of time, while hitting a narrow target on the surface, requires 'slamming on the brakes' in a very careful, creative and challenging way."

I felt the focus on "a very careful, creative and challenging way" of solving a technical problem would be particularly relevant to my students. And the way that the writing continues sounds like a personal conversation, so it was both easy and appealing for my students to read. The lower register terms they identified are underlined:

• "Landing on Mars is hard. Only about 40 percent of the missions ever sent to Mars - by any space agency - have been successful. Hundreds of things have to go just right during this nail-biting drop. What's more, Perseverance has to handle everything by itself. During the landing, it takes more than 11 minutes to get a radio signal back from Mars, so by the time the mission team hears that the spacecraft has entered the atmosphere, in reality, the rover is already on the ground. So, Perseverance is designed to complete the entire EDL process by itself - autonomously."

The casual tone starts with a very basic sentence: Landing on Mars is hard. No scientific or technical language needed!

Since my students are generally interested in the technology created for the flight and the scientific mission, I also focused on the website page with an overview of the spacecraft:

Link: https://mars.nasa.gov/mars2020/spacecraft/overview/

There are 5 spacecraft components (also see the visual accompanying this post):

• Cruise Stage
• Backshell
• Descent Stage
• Rover
• Heat Shield

Each component is described briefly, indicating what its function is. For example, the text for Descent Stage:

• "The descent stage is the rover's free-flying 'jetpack,' which separates from the backshell and uses eight engines to slow the final descent. It also contains the landing radar system used to make last-minute decisions about touchdown. Just before touchdown, the descent stage lowers the rover on cables before gently placing it on the surface. Once the rover is on the ground, the descent stage flies off to make its own uncontrolled landing on the surface, a safe distance away from the rover."

This page has a further link to the Rover, which is the component that my students are most interested in: https://mars.nasa.gov/mars2020/spacecraft/rover/

The page downloads a 3D model of the Rover on which it's possible to zoom in, rotate, and mouse over each component to get a closer look and more information. The written information underneath the model compares the components to body parts enabling the rover to function for survival. It is a very good example of using comparisons that a non-technical audience would understand:

• "It is car-sized, about 10 feet long (not including the arm), 9 feet wide, and 7 feet tall (about 3 meters long, 2.7 meters wide, and 2.2 meters tall). But at 2,260 pounds (1,025 kilograms), it weighs less than a compact car. In some sense, the rover parts are similar to what any living creature would need to keep it 'alive' and able to explore."

This comparison is continued in the brief description of the purpose of each part:

• body: a structure that protects the rover's "vital organs"
• brains: computers to process information
• temperature controls: internal heaters, a layer of insulation, and more
• "neck and head": a mast for the cameras to give the rover a human-scale view
• eyes and ears: cameras and instruments that give the rover information about its environment
• arm and "hand": a way to extend its reach and collect rock samples for study
• wheels and legs: parts for mobility
• electrical power: batteries and power
• communications: antennas for "speaking" and "listening"

Clicking on each of the parts brings you to a separate page with more information about that particular part.

Finally, a further resource is a Landing Toolkit for educators: https://mars.nasa.gov/mars2020/timeline/landing/

Much of the information was for use before the landing, but there are many more materials, and links with ideas for how to use them.