Reader response draft 1

In the articles, ”Mars 2020 mission Perseverance rover”(n.d.) and "NASA’s Self-Driving Perseverance Mars Rover ‘Takes the Wheel’" (2021), the National Aeronautics and Space Administration (NASA) documents the operation of the upgraded auto navigation system called AutoNav for the Perseverance rover to traverse the Martian surface for signs of ancient life along with locating and transporting sample collections of rock back to Earth for analysis. The article states that the AutoNav enables the rover to autonomously drive at faster speeds of up to 120 meters per hour while performing 3D mapping of upcoming terrain, hazard identification, and trajectory planning for obstacle avoidance, which consequently reduces the time taken to reach its destination as it can now travel through complex terrains instead of going around them. NASA also mentions that the AutoNav includes ENav which is an enhanced navigation software that aids in more accurate hazard detection of small, pointed rock protrusions which were undetected by the earlier version of AutoNav on the Curiosity rover and caused holes to be created on the wheels which hindered the rover's ability to navigate. Therefore, the underlying issues the Perseverance rover faces in terms of the components highlighted are further explained below.

The first issue that the Perseverance rover faces is that it cannot independently rely on the AutoNav to trek across Mars which is indicated in the article, "NASA’s Self-Driving Perseverance Mars Rover ‘Takes the Wheel’" (2021). It still requires human elements such as a team of specialists to provide additional guidance to generate a navigation course as well as to strategize the rover's operations such as investigating unique terrestrial features along with procuring the necessary samples that it comes across, likewise such instructions are performed by the rover the day after they are sent as there is a radio signal delay between Earth and Mars.

Furthermore, the second issue that the Perseverance rover faces is safely navigating over the Martian surface that is comprised of rougher ground with numerous small, sharp, and pointy rocks that could otherwise be detrimental in maintaining the structural integrity of the wheels and the rover itself and is shown in the article, "NASA’s Self-Driving Perseverance Mars Rover ‘Takes the Wheel’" (2021). Therefore, the ENav software is used for the detection of such hazards in conjunction with wheels themselves being modified to incorporate 48 treads with a slightly wavy design to aid in the traction and durability of the rover. Visual odometry is another system that assists in the rover's safe navigation over Mars as it maintains a record of the distance it has traversed from one location to the next to reach its targeted distance efficiently. Thus when the rover needs it to backtrack its path, it can refer to the former records to avoid potentially dangerous areas that it has previously encountered.

However, the use of visual odometry poses challenges for the rover as it functions based on the periodic images captured by cameras during locomotion, which are largely affected by environmental factors such as terrains that are not flat, inadequate or direct sunlight, and weather patterns such as dust storms, high winds, etc. Hence, these environmental factors as stated in the article, "Aqel, Marhaban, Saripan, Ismail, (2016). Review of visual odometry: types, approaches, challenges, and applications. SpringerPlus 5, 1897" affect the accuracy of the system as they can lead to an incorrect estimation of the resulting trajectory of the rover.

In conclusion, the Perseverance rover's navigation system utilizes diverse components and systems to safely and efficiently support the rover's navigation over the martian surface.

National Aeronautics and Space Administration(n.d.)Mars 2020 mission Perseverance rover https://mars.nasa.gov/mars2020/ 

National Aeronautics and Space Administration(2021, Jul 2)NASA’s Self-Driving Perseverance Mars Rover ‘Takes the Wheel’ NASA’s Self-Driving Perseverance Mars 

Aqel, Marhaban, Saripan, Ismail, (2016). Review of visual odometry: types, approaches, challenges, and applications. SpringerPlus 5, 1897. https://doi.org/10.1186/s40064-016-3573-7