EECS 4200/5200 Term Project (10%) sp21

Modeling of Soft Landing of Mars ‘Perseverance’ Rover

Introduction

On February 18, 2021 the Mars Perseverance Rover landed on Mars’s Jezero Crater. Sent to look

for signs of ancient life and to collect rock samples, the process of landing on Mars safely required

a team of scientists and researchers to derive a series of complex maneuvers. Over the course of

this project, you will take on the role of these scientists and create models of the soft landing

procedure.

Objectives of the Term Project

The term project’s primary objective is to impart practical skills necessary to develop a real-world

system model. The student is expected to be able to do the following by the completion of this

term project:

1. To generate a model of a practical system by the laws of the physical sciences governing

the system’s behavior. In this case, it is Translational Motion Mechanical System.

2. Convert the model into a Free Body Diagram with all acting forces presented.

3. Create a Set of Differential Equations pertaining to the diagram.

4. Presentation of the equation in Matrix form with State variables and Output.

5. Develop Signal Flow Graph and defining the System Transfer function.

6. Identification of key design parameters from literatures and reference material and

utilization/application to the modeling process.

7. Calculation of key parameters such as masses, velocities, gravity, etc. Any defined

values from correlating literature (web, text, papers) must be specified regarding author(s),

title, page, date, address (if Web).

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Background

While performing the soft-landing on Mars, the Perseverance rover underwent a series of stages

where numerous elements of the system would provide support ensuring a safe landing. As far as

the soft-landing is concerned, at approximately 12 kilometers from the surface of Mars, the

parachute of the Perseverance rover was deployed to slow its descent. After a reasonable amount

of deacceleration, the heat shield was removed, allowing the cameras onboard the rover to obtain

their first glimpse of the surface of Mars. Further into the descent, the engine of the hover unit was

activated as the backshell containing the connection to the parachute was separated. At this stage

of the descent, the rover’s landing was assisted by the hover unit providing upward thrust to

decrease the velocity at which it fell. Finally, after a predetermined height over the surface was

reached, the hover unit took on the role of a helicopter and hovered in position. Then, the hover

unit behaved like a “skycrane” where it gradually lowered the rover onto the surface.

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Project Description

The project you are assigned is concerned with the soft landing of the Perseverance rover; in other

words, starting with the deployment of the parachute and onwards as it descends. For purposes of

the project, we are to analyze the soft-landing system at the instant in which the parachute is

deployed and the hover unit engines are activated providing upward thrust. In order words,

the backshell is still attached while the heat shield has been removed. Furthermore, we

assume the “skycrane” is already activated with its full length and the rover has touched the

surface. As a student, you are to model this landing system and derive a series of requirements

based upon the description provided below:

1. The masses of the system considered are from the hover unit (M1) and the rover (M2).

The backshell is assumed negligible and can be ignored as a mass (for simplicity).

2. As opposed to the backshell, we will assume the parachute is connected straight to the

hover unit. It can be thought of as a spring (K1), while the “skycrane” the hover unit

uses to lower the rover is also a spring (K2).