Level 1 - Absolute Beginner
Mars is a planet. It is red and very dry. NASA sent a robot car to Mars. The robot car is called Perseverance.
The robot car drives on Mars. It has now driven 28 miles. That is farther than any other machine on another world.
The old record came from a different robot car called Opportunity. Opportunity needed almost 15 years. Perseverance needed only five and a half years.
Perseverance drives by itself most of the time. It looks at the ground and finds a safe way to go. It is looking for signs of old life on Mars.
- planet
- A very large round object in space that goes around a star.
- robot
- A machine that can do work by itself.
- drive
- To move along in a vehicle.
- record
- The best or biggest result that anyone has ever reached.
- mile
- A way of measuring distance. One mile is about 1.6 kilometres.
- machine
- A thing built with moving parts that does a job.
- safe
- Not in danger.
- life
- Living things such as plants, animals and people.
Level 2 - Elementary
NASA's Perseverance rover has broken a record on Mars. On October 11 its odometer reached 28.10 miles, which is 45.22 kilometres. No machine has ever driven so far on another world.
The old record belonged to Opportunity, another NASA rover, which drove 28.06 miles between 2004 and 2018. Opportunity needed almost fifteen years. Perseverance has done it in about five and a half.
The secret is a system called AutoNav. It builds a map of the rocks ahead in three dimensions and chooses a safe path without waiting for instructions from Earth. Engineers call this thinking while driving. More than 90 percent of the rover's distance has used AutoNav.
Perseverance landed in Jezero Crater, which was once a lake. It has collected 29 samples of rock and soil. It is now driving towards a place called Idubi, where scientists hope to find signs that hot water once flowed through the rock, because hot water could have supported life.
- rover
- A vehicle that drives on the surface of another world.
- odometer
- The instrument that shows how far a vehicle has travelled.
- system
- A set of parts working together to do a job.
- instruction
- An order or direction telling someone what to do.
- path
- The way or route taken from one place to another.
- sample
- A small amount of something taken away to be studied.
- crater
- A large bowl-shaped hole in the ground.
- ancient
- From a very long time ago.
Level 3 - Intermediate
NASA's Perseverance rover has taken the record for the longest distance ever driven on another world. On October 11, its 2,006th Martian day, the odometer reached 28.10 miles, or 45.22 kilometres, edging past the 28.06 miles set by the Opportunity rover between 2004 and 2018.
The margin is small but the timescale is not. Opportunity needed nearly fifteen years to cover that ground, while Perseverance has managed it in roughly five and a half. The difference lies in autonomy. A system called AutoNav builds a three-dimensional map of the terrain ahead, identifies obstacles and selects a route without waiting for commands from Earth, a process engineers describe as thinking while driving.
The contrast with earlier missions is striking. More than 90 percent of Perseverance's total distance has been driven with AutoNav assessing the ground, compared with roughly 5 percent for the earlier autonomy aboard Opportunity and Spirit. Limits remain, however: glare on the navigation cameras still forces operators to stop driving by mid-afternoon whenever the rover is heading towards the Sun.
The record is a means rather than an end. Perseverance began on the floor of an ancient lakebed inside Jezero Crater and has gathered 29 rock and regolith samples. It is now crossing an area called Lac de Charmes towards a site named Idubi, beyond the crater's western rim, where researchers hope to find traces of ancient hydrothermal systems that could once have supported life. NASA has extended the mission to around the end of 2028.
- autonomy
- The ability to act independently, without direct control.
- terrain
- The physical surface and shape of an area of ground.
- obstacle
- Something that blocks the way and must be avoided.
- margin
- The amount by which one thing exceeds another.
- regolith
- The loose rock and dust covering the solid surface of a planet.
- hydrothermal
- Involving hot water moving through rock.
- glare
- Strong, dazzling light that makes it hard to see.
- extend
- To make something last longer than first planned.
Level 4 - Advanced
Records are rarely interesting in themselves; what they measure is. On October 11, its 2,006th Martian day, NASA's Perseverance rover pushed its odometer to 28.10 miles, or 45.22 kilometres, displacing the 28.06 miles that Opportunity accumulated between 2004 and 2018. The two distances are nearly identical. The elapsed times are not, and that gap is the actual finding.
Opportunity required almost fifteen years; Perseverance has taken about five and a half. The decisive variable is not motor power but delegation. AutoNav, the rover's onboard navigation system, constructs a three-dimensional model of the terrain, classifies hazards and commits to a route without routing the decision back through Earth, an arrangement engineers summarise as thinking while driving. More than 90 percent of Perseverance's mileage has been covered under that regime, against roughly 5 percent for the first-generation autonomy carried by Opportunity and Spirit.
The remaining constraints are instructive about where autonomy still fails. Glare striking the navigation cameras when the rover drives sunward degrades the very imagery AutoNav depends upon, which obliges operators to halt by mid-afternoon. Software now in development aims to reduce unnecessary steering and to cross-check the rover's position against orbital maps. Mark Maimone, deputy team chief for robotic operations, framed the trajectory bluntly: Perseverance, he said, is a better driver than the one that landed, and the team is not done.
Mobility, in any case, is in service of sampling. Having begun on the floor of an ancient lakebed in Jezero Crater and collected 29 rock and regolith cores, the rover is traversing Lac de Charmes towards Idubi, a target beyond the crater's western rim selected for the possibility of preserved hydrothermal systems, the sort of warm, mineral-rich setting in which terrestrial life is thought to have gained its first foothold. With the mission extended to roughly the end of 2028, and a block of ancient crust named Rainbow Falls further along the route, the odometer will keep climbing. It remains the least important number the mission will produce.
- delegation
- The handing over of a decision or task to another party.
- hazard
- A source of danger that must be identified and avoided.
- degrade
- To reduce the quality or usefulness of something.
- oblige
- To force or require someone to do something.
- traverse
- To travel across a region or surface.
- constraint
- A limit that restricts what can be done.
- foothold
- A secure initial position from which further progress is possible.
- instructive
- Providing useful knowledge or insight.
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