General Knowledge · Class 10 · Science and space
India in space
Chandrayaan-3 had to land on the Moon without a single parachute. Why could it not use one, and how did it slow down?
Small test at the end: scroll down to the end of this page for five short questions that check what you have learnt. Tap an answer, then press Check answer. Go to the questions ↓
Jump to: Read first · Try it away from the screen · Check it yourself · Check yourself · For teachers
Read first
6 facts. The questions below make you use them, not just remember them.
- On 23 August 2023, Chandrayaan-3's lander, Vikram, touched down near the Moon's south pole. India became the fourth country to land softly on the Moon and the first to land near its south pole. India now marks 23 August as National Space Day.
- The Moon has almost no air, so a parachute has nothing to push against. Vikram slowed down by firing its own engines downwards, steering itself all the way to the ground.
- Some deep craters near the Moon's south pole never get sunlight. They stay extremely cold and may hold water ice, which future missions could use for drinking water, air or rocket fuel.
- Mangalyaan, the Mars Orbiter Mission, was launched on 5 November 2013 and reached Mars orbit on 24 September 2014. India was the first Asian country to reach Mars orbit, and the first country to do it on its first attempt.
- Aditya-L1, India's first mission to study the Sun, watches it from near a point called L1, about 15 lakh (1.5 million) km from Earth. There, the pulls of the Sun and the Earth balance so that the spacecraft keeps pace with Earth and sees the Sun all the time.
- ISRO launches from Sriharikota on the east coast. Earth spins from west to east, so a rocket launched eastward gets a free push, and the used rocket parts fall into the sea, away from people.
Offline
Try it away from the screen
Tonight or on the next clear evening, look at the Moon and sketch its shape. Do it again three days later. Which way is the bright part growing or shrinking? Keep the sketches on paper and compare them with a calendar that shows the Moon's phases.
Make it on paper. Keep it with you. Nothing to upload.
Check it yourself
Space news spreads fast, and many viral posts get dates and numbers wrong. For an Indian mission, the most reliable source is ISRO itself: its website (isro.gov.in) and its press releases. A good habit: before you share a space "fact", find it in the original source and check the date.
Check yourself
Five questions about what this page teaches. Choose an answer and press Check answer, or open "See the answer and why". Nothing is saved or sent: your choices stay on this screen and disappear when you leave or reload the page.
How do you want to answer? You choose, and you can change at any time.
See the answer and why
- A. The Moon's gravity is stronger than Earth's, so a parachute would tear Not this one. The Moon's gravity is about one sixth of Earth's, weaker, not stronger.
- B. The Moon has almost no air, so a parachute has nothing to push against Correct. Yes. Parachutes work by pushing against air. With no air, the lander used its engines instead.
- C. Parachutes only work over water Not this one. Parachutes work wherever there is air, over land or sea. That is how soldiers and space capsules land on Earth.
- D. Sunlight on the Moon would melt the parachute Not this one. Sunlight on the Moon is harsh, but parachute cloth can be made to cope. The real problem is the missing air.
See the answer and why
- A. 5 seconds Correct. Yes. 15,00,000 ÷ 3,00,000 = 5, so about 5 seconds.
- B. 50 seconds Not this one. Count the zeros again: 15,00,000 ÷ 3,00,000 is 15 ÷ 3, which is 5.
- C. 500 seconds Not this one. That would be true if radio travelled only 3,000 km each second. It is a hundred times faster.
- D. 0.2 seconds Not this one. That is 3,00,000 ÷ 15,00,000, the division the wrong way round. Time = distance ÷ speed.
See the answer and why
- A. Earth spins west to east, giving the rocket extra speed, and used parts fall into the sea Correct. Yes. The spin is a free push, and the sea to the east keeps falling stages away from people.
- B. The Sun rises in the east, so the rocket's solar panels start charging faster on the way up Not this one. A rocket climbs through the sky in minutes. Its direction is chosen for speed and safety, not sunrise.
- C. The Moon is always in the east Not this one. The Moon rises in the east but moves across the sky, and most launches do not go to the Moon at all.
- D. There are never clouds over the east coast Not this one. The east coast gets clouds and even cyclones. Launches wait for good weather.
See the answer and why
- A. The rocket must arrive in summer on Mars Not this one. Mars seasons matter for some landers, but the window is set by where the two planets are.
- B. Earth and Mars must be placed so the spacecraft's path meets Mars using the least fuel Correct. Yes. Both planets move around the Sun. The good line-up, where the path is cheapest, repeats about every 26 months.
- C. Mars stops moving around the Sun for a few weeks Not this one. Planets never stop moving. The window comes from their positions, not a pause.
- D. Mars can be seen from Earth only once every 26 months, so the spacecraft would get lost at other times Not this one. Mars is visible in our sky for much of the time. Seeing it is not what limits a launch.
See the answer and why
- A. It is the side of the Moon that always faces the Sun Not this one. No side always faces the Sun; every part of the Moon gets day and night as it turns. Some polar craters stay dark because the Sun is always low there.
- B. It is the warmest part of the Moon, so machines work better Not this one. It is among the coldest places known in the solar system, because some craters stay in shadow.
- C. It is the only part of the Moon with air Not this one. The Moon has almost no air anywhere, including the south pole.
- D. Some craters there never get sunlight and may hold water ice Correct. Yes. Ice kept frozen in the dark could one day give water, air and fuel to explorers.
For teachers and grown-upsWhere the facts come from, and how to use this round.
Sources and notes
- Dates from ISRO: Chandrayaan-3 landing 23 August 2023 (National Space Day); Mars Orbiter Mission launched 5 November 2013, Mars orbit 24 September 2014; Aditya-L1 launched 2 September 2023, reached its orbit around L1 on 6 January 2024.
- Links: NCERT Class 9 gravitation, Class 10 light; the speed of light, about 3 × 10⁵ km/s.
- For a stronger task, ask learners to find one wrong number in a social-media post about a mission and correct it from the original source.