Case 06: Returner

Introduction

The purpose of this course is to introduce students to the components of the Return Vehicle and the knowledge associated with performing missions on the Moon. Students will use the micro:bit SpaceX kit to learn how to write a program to control the operation of the return vehicle.

Teaching Objectives

• Understand the structure and operation of the Return Vehicle.
• Learn about the tasks performed by the Return Vehicle.
• Learn how to build and program the return vehicle.

Preparation

Before starting the lesson, please make sure you have prepared the following necessary materials:

	micro:bit V2
	Nezha Breakout Board V2
	PlanetX Smart Motor
	PlanetX Temperature and Humidity Sensor
	PlanetX Line Following Sensor
	Bricks Pack
	USB cable
	Computer

These materials will provide you with a complete experience and ensure that you can follow through and learn smoothly. If you are ready for the above, we can move on to the next step.

Teaching and Learning Process

Introducing the Lesson

Have you ever thought about what a returner is made of and how it works? In this lesson, we'll explore how to build a replicator with building blocks and control its operation with a graphical program.

Ready to explore the world of space travel with the micro:bit Space Science Kit? Now, let's get started on this fun learning journey!

Exploration Activities

• How do I build a replicator?
• What if I write a simple program to make a returner run?
• How do returners work with returners?

Case Study

Based on the existing form and composition of returners, please open the discussion and rationalize the design of block returners.

Example

Code Programming

Add a software library

Go to“makecode.microbit.org”，and click New Project.

Enter the project name in the pop-up window and click Create.

Click on Extension in the code drawer.

Type nezha2 in the popup and click on the search icon, click on the nezha2 repository when it is displayed. Load the PlanetX library in the same way.

Component Connection

Please refer to the wiring diagram below to connect the components to the corresponding interfaces.

Example program

Refer to the program link: https://makecode.microbit.org/_Fey9AV08AADD

Please adjust the speed of the Planet Series Smart Block motor appropriately for your classroom.

Download the program

Use the USB cable to connect the PC and the micro:bit V2.

After a successful connection, a disk drive named MICROBIT will be recognized on the computer.

Click on the bottom left corner of the ，and select Connect Device.

Click。

Click。

Select BBC micro:bit CMSIS-DAP in the popup window, and then select Connect, so far, our micro:bit has been connected successfully.

Click Download Program.

Teamwork and Presentation

Students are divided into small groups and work together to create and program the returner.

Students are encouraged to cooperate, communicate and share their experiences with each other.

Each group will have the opportunity to show the other groups the returners they have made and demonstrate them.

Expected results: After starting up, the re-entry vehicle will travel along the lunar-terrestrial return trajectory, while displaying the temperature and humidity data of the "capsule".

Summarize and Reflect

Review the course content and remind students what knowledge and skills they have acquired.

Lead students in a discussion about the problems and difficulties they encountered during the production process and how they solved them.

Guide students to think about directions for optimization and improvement of returners, such as what other interesting cases can be made.

Related Knowledge

The return vehicle during a lunar landing is a key component in accomplishing a lunar landing mission, responsible for safely bringing astronauts and scientific equipment from circumlunar orbit to the lunar surface and bringing astronauts back to circumlunar orbit after the mission is completed. The design of the Return Vehicle is very complex and requires multiple functions to meet the challenges of the lunar environment. Here is some general knowledge about the return vehicle composition:

Basic composition

1. Lunar Module:
   • This is the part of the return vehicle that contains the astronauts, also known as the crew module or command module. It usually contains life support systems, communications equipment, navigation systems, and emergency escape devices.
2. Propulsion Module:
   • Contains the main engine and propellant tanks, which are used to control the descent rate and direction of the return vehicle to ensure a smooth landing and re-takeoff.
3. Landing legs and cushions:
   • Used to absorb shock during landing and prevent the returner from tipping over or being damaged.
4. Solar panels:
   • Provide electrical power, especially on long missions, for powering electronic equipment and keeping life support systems operational.
5. Attitude Control System:
   • Includes small thrusters and reaction wheels used to adjust the attitude of the return vehicle in space.
6. Navigation and Guidance System:
   • Uses laser rangefinders, inertial navigation units and astrometers to determine position and velocity and ensure accurate landings.
7. Scientific instruments and laboratory equipment:
   • May contain cameras, spectrometers, seismometers, etc., to perform scientific research and data collection.
8. Lunar rovers or other ground vehicles:
   • Some return vehicles may carry lunar rovers or rovers so that astronauts can leave the return vehicle for more extensive exploration.
9. Sample collection and storage system:
   • If the mission includes collection of lunar samples, the return vehicle will contain equipment for sample collection and storage.

Special design considerations

• Power system: In order to land and take off on the Moon, the return vehicle must use a different propulsion system than chemical rockets because there is no atmosphere on the Moon to generate lift. A combination of liquid fuel and oxidizer is typically used.
• Weight and size constraints: The return vehicle must be as lightweight as possible to minimize launch costs and increase efficiency. At the same time, it needs to have enough space to accommodate astronauts and equipment.
• Thermal control systems: The temperature on the lunar surface is extremely variable, and the return vehicle must be able to maintain a suitable temperature inside.
• Redundant Systems: To ensure the safety of the astronauts, many of the critical systems are backed up in case a component fails.

Specific examples

• U.S. Apollo Eagle Return Vehicle: consists of the Lunar Module and the Ascent Module, the latter being used for re-entry into circumlunar orbit.
• China's Lunar Range Return Vehicle (LRV): part of China's manned lunar landing program, designed to transport astronauts to and from the surface of the Moon.
• NASA's Nova C return vehicle: uses methane and oxygen as fuel and is designed to explore the south polar region of the Moon.

The design of each return vehicle varies according to its specific mission requirements and the spacecraft architecture used.