Year 7 Science · Unit 4 · Lesson 18
Extension · Apply Worksheet
Learning Goals
Extension · optional
The history of space exploration and the difficulties of deep-space travel go further than Year 7 asks for and are not assessed. One part does count: this unit asks you to investigate how a recent advance in science increased what we know about the Universe, and a present-day mission is a fair choice for that.
Fill the gap
Choose the correct word from the word bank. Each word is used at most once. Two words are not needed: cross them out.
NASA’s programme aims to send astronauts back to the , this time to stay for longer. Travelling to Mars is hard because of the huge , harmful , the long time away from home, and the need to carry enough .
Order the milestones
Work out which event each row describes. Number them from 1 (earliest) to 5 (latest, or still to come).
| Number | Event |
|---|---|
| Vostok 1 carries a Soviet pilot around the Earth. | |
| Crews go back to the lunar surface to stay for longer. | |
| Armstrong and Aldrin step out onto the Moon. | |
| A beeping satellite the size of a beach ball reaches orbit. | |
| Adelaide becomes home to a new national agency for space. |
Cause and effect: a reusable rocket
Fill the two empty boxes. Each box is caused by the one before it, and row 2 carries on from the end of row 1.
Scenario: messages to a Mars rover
Radio messages travel at the speed of light, but take time to cross space. In this made-up example, a message takes 12 minutes in either direction between Earth and a Mars rover. Use one clock throughout and ignore processing or relay delays. At 09:00, a team on Earth sends a command. The rover sends an acknowledgement as soon as that command arrives. Later, its camera detects an obstacle that it would hit in 5 seconds if it kept moving. Its onboard software can stop it immediately without waiting for Earth.
The numbers and clock times are invented teaching values. Radio-delay and rover-control background: NASA on rover autonomy. Location note: Tidbinbilla is a different facility from Parkes in New South Wales, known today by its Wiradjuri name Murriyang; see CSIRO on Murriyang.
1. At what time does the command reach the rover, and what is the earliest time the team on Earth can receive its acknowledgement?
2. Should the rover wait for a new stop command from Earth when it detects the obstacle? Use the signal travel time to justify your answer.
Read the data: Moon or Mars?
Scenario: planning the next big trip
A space agency compares two destinations for a crewed mission.
| Destination | Distance from Earth | Typical travel time |
|---|---|---|
| The Moon | about 384 000 km | about 3 days |
| Mars | about 55 million km (at its very closest) | about 7 months |
Source: rounded standard values (the lesson says only that a Mars trip takes many months).
3. About how many times farther from Earth is Mars at its closest than the Moon? Give your answer to the nearest ten.
About times farther
4. Artemis aims to send astronauts back to the Moon to learn how to live and work there. Use Table 1 to explain why the Moon is a sensible place to practise before trying Mars.
5. Explain why sending humans to Mars would be much harder than the Apollo trips to the Moon.
Fill the gap
Artemis; Moon; distance; radiation; supplies. Not used: Apollo, Sun. Five correct = 3; three or four = 2; one or two = 1. [3 marks]
Order the milestones
Reading down the table as printed, the correct numbers are 2, 5, 3, 1, 4. In order: Sputnik 1 (1957); Gagarin on Vostok 1 (1961); Apollo 11 (1969); Australian Space Agency (2018); Artemis (future).
Cause and effect: a reusable rocket
Box 1: the rocket can be flown again (1). Box 2: a new rocket does not have to be built and thrown away for every flight (1). [2 marks]
Question 1
The command arrives at the rover at 09:12 (1). Its immediate acknowledgement takes another 12 minutes, reaching Earth at 09:24 (1). [2 marks]
Question 2
No: a new command from Earth needs 12 minutes, much longer than the 5 seconds before collision, so the rover should stop itself (1). Also accept: reporting the hazard and receiving a reply takes 24 minutes, which is too late (1 total). [1 mark]
Read the data: Question 3
55 000 000 ÷ 384 000 (1) ≈ 143, so about 140 times farther (1). [2 marks]
Question 4
The Moon is only about 3 days away, not about 7 months (1), so crews can be resupplied or return home quickly while they learn to live and work in space (1). [2 marks]
Question 5
Marking guide: 1 distance: about 140 times farther than the Moon; 1 so about 7 months, not 3 days; 1 radiation beyond Earth’s protection damages the body; 1 time: away from home, family and rescue for years; 1 supplies: air, water and food carried, recycled or grown; 1 solving these drives new science and technology. [6 marks]
Model answer: Mars is about 140 times farther than the Moon, so the trip takes about 7 months, not 3 days. All that time the crew faces radiation outside Earth’s protection, far from home and rescue. All air, water and food must be carried, recycled or grown. Solving this will drive new science and technology.
Common error: Q3, not writing both distances in km first.