Mars Missions and the Search for Life · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Journey to Mars: Challenges and the Search for Life

Science · Space Exploration · ages 13-14
Name ______________________   Date ____________

  1. A trip to Mars takes about the same amount of time as a trip to the Moon.

    Circle one:   True   False

  2. Which of these best explains why astronauts on the International Space Station face less radiation risk than astronauts traveling to Mars?

    • The ISS still orbits inside Earth's protective magnetic field
    • The ISS is built from thicker metal than a Mars spacecraft
    • Radiation only exists in space near Mars, not near Earth

  3. What does SETI mainly search for as a possible sign of intelligent life elsewhere?

    • Photographs of cities on other planets
    • Radio signals or laser flashes that look artificial
    • Messages written in a human language

  4. A crew member feels irritable and homesick a year into the flight, cut off from in-person contact with family. Which Mars mission challenge is this?

    • Psychological isolation
    • Bone density loss
    • Solar radiation exposure

  5. An astronaut exercises two hours a day on the way to Mars but still loses bone density. Why?

    • The exercise machines stop working after a few weeks in space
    • Astronauts forget to eat enough calcium during the flight
    • Low gravity means bones and muscles don't have to work as hard, even with exercise

  6. A signal takes 20 minutes to travel from Mars to Earth. Mission Control replies immediately. How many minutes pass before the astronaut hears the reply?

    010203040to Earthreply back

    Answer: ______________

  7. The Fermi Paradox asks 'where is everybody?' Which pair below describes two contrasting proposed answers?

    • The idea that we are alone vs. the idea that time travel is possible
    • The Big Bang theory vs. the theory of relativity
    • The Great Filter (something stops civilizations from surviving long enough to be detected) vs. the Rare Earth hypothesis (the right conditions for intelligent life are extremely uncommon)

  8. A classmate says: 'We've searched the whole galaxy for alien radio signals and found nothing, so there's definitely no one else out there.' What's wrong with this claim?

    • Scientists have actually already found several confirmed alien signals
    • Only a tiny slice of the sky and possible signal types has actually been searched so far
    • Radio signals can't travel through the vacuum of space
LightMySky · lightmysky.comW1-mt_EIbltgXRWR-s1

Answer key

For grown-ups. Fold this page away before handing over the rest.

Journey to Mars: Challenges and the Search for Life W1-mt_EIbltgXRWR-s1

  1. False · A Moon trip takes about three days. A trip to Mars takes roughly seven months each way.
  2. The ISS still orbits inside Earth's protective magnetic field · Earth's magnetic field deflects most charged particles from the sun and deep space. A ship traveling to Mars leaves that protection behind.
  3. Radio signals or laser flashes that look artificial · SETI scans for radio signals or laser pulses that stand out from natural background noise, not for pictures or written words.
  4. Psychological isolation · Being separated from normal social contact for years is the isolation challenge, separate from the physical effects of radiation or low gravity.
  5. Low gravity means bones and muscles don't have to work as hard, even with exercise · Exercise slows the loss but doesn't fully replace the constant pull of gravity that keeps bones and muscles strong on Earth.
  6. 40 · 20 minutes there plus 20 minutes back equals 40 minutes round trip.
  7. The Great Filter (something stops civilizations from surviving long enough to be detected) vs. the Rare Earth hypothesis (the right conditions for intelligent life are extremely uncommon) · These two ideas disagree on the cause: one says life is common but doesn't survive or get noticed, the other says intelligent life itself is rare.
  8. Only a tiny slice of the sky and possible signal types has actually been searched so far · SETI has covered a small fraction of stars, frequencies, and time. No detection yet doesn't prove no one is out there.
Worksheet · LightMySky