Printable worksheet · Ages 11 to 14 · about 20 minutes

How long does a message take to reach Voyager 1?

A one-page worksheet using Voyager 1's live distance: the speed of light, the light-day and the light-year.

Numbers

Today's numbers come from the Deep Space map, captured when this page loaded: 18:38 UTC on 3 November 2026. Print the class set in one go so every copy matches the teacher notes. Reload for new numbers.The boxes are left blank. Pupils open the Deep Space map and copy in the numbers themselves, so answers vary a little: the teacher notes give the method and the range to accept.Live numbers are not available right now, so the boxes are blank: pupils look them up in the Deep Space map.

Orbital Radar · Space for Schools
Ages 11 to 14 · Light and space

How long does a message take to reach Voyager 1?

Voyager 1 left Earth in 1977 and is the furthest spacecraft from us. Radio messages travel at the speed of light.

Name Class Date
Today's number from Deep Space, 18:38 UTC on 3 November 2026
Voyager 1's distance from Earth
25,866,000,000 km
Light travels about
300,000 km every second
1 hour = 3,600 seconds
1 day = 86,400 seconds

Open orbitalradar.com/deep-space, find Voyager 1 and copy its distance from Earth.

  1. Write Voyager 1's distance in billions of kilometres, to 1 decimal place.[1]

    billion km

  2. How many seconds does a radio message take to reach Voyager 1? Use: time = distance ÷ speed.[2]

    s

  3. Change your answer to hours. Is it more or less than one day?[2]

    hours

  4. A light-day is the distance light travels in one day. How far is that?[2]

    km

  5. Engineers send Voyager 1 a command and it replies straight away. How long before they hear back?[1]

    hours

  6. Sunlight takes about 500 seconds to reach the Earth. How many times further away than the Sun is Voyager 1?[2]

    times

  7. The nearest star after the Sun is about 4.2 light-years away. About how many light-days is that?[2]

    light-days
Extension  Voyager 1 travels about 17 km every second. Roughly how many years would it take to travel one light-year? [3]
orbitalradar.com/schools/uk/worksheets/voyager-light-timeNumbers captured 18:38 UTC, 3 Nov 2026Free to copy for teaching
Teacher notes and answersNot on the pupil sheet. Printed only with "Print with answers".

Teacher notes: How long does a message take to reach Voyager 1?

Worked from the distance on today's sheet: 25,866,000,000 km (18:38 UTC on 3 November 2026).

Pupils looked up their own distance, so answers vary a little: check the method.

Total 12 points, plus 3 for the extension.

Answers

  1. 25.9 billion km
  2. distance ÷ 300,000 = 86,220 s
  3. seconds ÷ 3,600 = 23.9 hours: less than one day
  4. 300,000 × 86,400 = 25,920,000,000 km (25.9 billion km)
  5. Twice the one-way time: about 48 hours
  6. seconds ÷ 500 = about 172 times further than the Sun
  7. 4.2 × 365 = about 1,534 light-days

Extension: one light-year is about 300,000 × 31,600,000 = 9.5 million million km. At 17 km/s that takes about 560 billion seconds, or roughly 17,600 years (accept 17,000 to 18,000).

About 18 November 2026

Voyager 1 is the first spacecraft to be one light-day from Earth, on 18 November 2026. Before then, question 3's answer is "less than a day"; afterwards it is "more". With light rounded to 300,000 km/s, a light-day comes out about 18 million km longer, so the switch shows up about a week later: accept either answer in the week after the date.

Curriculum

England: KS3 Space physics, the light year as a unit of astronomical distance, and KS3 Light, the speed of light. Wales: progression step 4, Forces and energy. Northern Ireland: KS3 Science, Earth and Universe, and CCEA GCSE Physics 2.5.18 to 2.5.20.

How these worksheets work

One page, free to print and copy for teaching. The numbers on the sheet are captured from the live tool when the page loads, and printed with the time, so a class set printed together matches the teacher notes. Reload for new numbers.

No sign-in, no ads, and nothing for pupils to install.

Where this fits

All United Kingdom activities