Four images representing different types of space observations, including ground-based telescopes, space telescopes, flyby spacecraft, and orbiter spacecraft


This lesson will help students better understand the process of designing space missions as they explore various observation techniques scientists use to study distant objects like asteroids. Students will evaluate each technique to better understand the design of NASA missions like the Psyche mission to a metal-rich asteroid.



  • Students may record their observations independently or work in groups of two to four to observe and record their observations together.
  • If students have online access to the worksheets, they can complete them electronically.


For millennia, humans have looked at the sky at night and wondered about the objects they see. Until the Space Age, we were limited to Earth-based observations, using just our eyes or telescopes. One advantage of observing space from Earth is anyone can do it. However, from Earth’s surface, our sky observations are obstructed by our atmosphere. To overcome this, scientists have placed telescopes in space to better observe without atmospheric interference. Images returned from the Hubble Space Telescope, the James Webb Space Telescope and other space-based observatories have provided new insights into the mysteries of our solar system and beyond.

In addition to using ground-based and space-based telescopes to observe, NASA sends spacecraft to examine space objects up close. These spacecraft can:

Each type of mission has advantages and disadvantages. The simpler the mission, the lower the cost, but less science is accomplished. The more complex missions like orbiters, landers, and rovers cost more but stand to return a tremendous number of scientific discoveries.

Psyche is one of millions of asteroids orbiting the Sun between Mars and Jupiter. But scientists are particularly interested in Psyche because it's thought to contain a large amount of metal and could be the remnant of a small planet's core. Scientists believe that even rocky planets like Earth have metallic cores, but they are not reachable because they are too far below the planets’ crusts. By sending a spacecraft to explore Psyche up close, scientists could have the unique opportunity to learn more about the deep interior of Earth and other planets. So NASA has designed a space mission, also named Psyche, to do just that.

A cube-shaped spacecraft with two long wing-like solar arrays in the shape of crosses flies toward a large asteroid that appears to have patches of rocky and metal material on its surface.

This animation shows an artist's rendering of the Psyche spacecraft going into orbit around the Psyche asteroid, a metal-rich object that orbits in the main asteroid belt between Mars and Jupiter. Credit: NASA/JPL-Caltech/ASU | + Expand image

Why did NASA choose to send a spacecraft to orbit the asteroid? This lesson will help students better understand the answer to this question.

Observations often lead to a question. Someone sees something and asks themselves, “What’s that?” They then start looking more closely and collaborating with others to study their findings. This is what scientists do as well. Scientists start with basic observation techniques and then start asking questions. They might notice a pattern or that there’s an apparent cause-and-effect relationship between things. They might observe a particular system, structure, or state of matter. These are all valuable observations.

Anyone can make observations. Robert Holmes of Westfield, Illinois, started observing asteroids as a hobby. Henow works for NASA and tracks asteroids in his backyard. Watch this short video below to learn more:

Backyard astronomer Robert Holmes of Westfield, Illinois, is part of NASA's army of observers scanning the night sky for asteroids. By observing and tracking asteroids, NASA programs can determine whether an asteroid is potentially hazardous to Earth -- now or years in the future. | › View transcript and download

In this lesson, students will practice making observations of asteroids, a dwarf planet, a protoplanet, and a Kuiper Belt object, which is similar to an asteroid except it’s located beyond the orbit of Neptune. Observations will then become evidence for making decisions for future missions like Psyche.


  1. Review the various methods scientists at NASA might use to observe objects in the solar system:

    • Earth-based telescope
    • Space telescope
    • Flyby spacecraft
    • Orbiter spacecraft

    Teams of scientists observe in these ways to collect empirical evidence, which is knowledge gained through direct or indirect observation.

  2. Hand out the observation worksheets and tell students they will be considering limitations and benefits to each observation method and what they might learn about asteroids, dwarf planets, protoplanets, and Kuiper Belt objects using each of these methods. Throughout their observations, students will record what they observe just like NASA scientists do. It's important that they document their observations to help them make future decisions.
  3. Earth-based telescope: Tell students that our first mission will be to observe an asteroid from Earth through a telescope. Ask students what limitations observing from Earth might have. Primarily, our atmosphere acts like a filter, covering our view of the asteroid. Also, we are very far away from the asteroid.

    • Reveal the image of asteroid 2014 AA viewed from Earth through the Catalina Sky Survey observatory. Ask students to record their observations on their worksheet and list their questions.
      A squished dot (almost a dash in this view) among a field of bright splotchy stars is circled in pink.

      Circled in pink is the asteroid named 2014 AA. It was the second one ever detected on course to impact Earth. It was estimated to be about 6 to 10 feet (2 to 3 meters) in diameter, and it harmlessly hit Earth's atmosphere over the Atlantic Ocean about 20 hours after its discovery in this image captured by NASA's Catalina Sky Survey near Tucson, Arizona. | › Full image and caption

    • Tell students that scientists share their observations with other scientists, so they may learn from each other. Have students share their observations with a partner or within their small group and discuss benefits and limitations to this method of observation.
    • Share with students that, as they may have noticed, Earth-based observations are easy to do, but they don’t answer all our questions.
  4. Space telescope: We can also observe space objects using a space-based telescope, such as the Hubble Space Telescope or the James Webb Space Telescope. Note that it can be challenging to get observation time with space-based telescopes. Scientists have to write proposals and compete to get even a short amount of observing time. As such, students will only have 30 seconds of observation time for this mission.

    • Show the Hubble Space Telescope image of dwarf planet Ceres and protoplanet Vesta that orbit in the asteroid belt.
      On the left is a hazy view of Ceres, which is relatively spherical and appears mostly brown with a couple bright white spots at its center and upper right and with several darker bluish splotches at its edges. Vesta, on the right, is more potato-shaped and has more mixed splotches of brown and blue.

      To prepare for the Dawn spacecraft's visit to Vesta, astronomers used the Hubble Space Telescope to snap new images of the asteroid as well as Dawn's second destination, the dwarf planet Ceres. | › Full image and caption

    • Ask students to record their observations on their worksheet and list their questions.
    • Have students share their observations with a partner or within their group and discuss benefits and limitations to this method of observation.
  5. Flyby spacecraft: Another means of observation is through a flyby mission, which is when a spacecraft makes a close pass by an object but does not go into orbit around it. Spacecraft will often fly by an object or planet to get an extra push for a journey to another destination. This technique is called a gravity assist, and it's used to change the velocity of the spacecraft.

    • Reveal the photo sequence from the New Horizons flyby of Arrokoth, which is also known as trans-Neptunian object 2014 MU69. Arrokoth is similar to an asteroid, but it is located in the Kuiper Belt, beyond the orbit of Neptune, rather than in the asteroid belt between Mars and Jupiter.

      The dot getting closer and eventually resolving into close-up images of an object that looks like a rocky snowman shows the view of Kuiper Belt object 2014 MU69 (nicknamed Ultima Thule) as seen by NASA’s New Horizons spacecraft as it flew by from Dec. 7, 2018 to Jan. 1, 2019. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/National Optical Astronomy Observatory/Brian May/Maria Banks/Roman Tkachenko | Watch on YouTube

    • Remind students to record their observations on their worksheet and list their questions.
    • Have students share their observations with a partner or within their group and discuss benefits and limitations to this method of observation.
  6. Orbiter spacecraft: Let’s try one more observation method, an orbiter spacecraft. These missions are conducted by having a spacecraft go into orbit around an object for a prolonged period of time to conduct scientific investigations. This is how NASA's Psyche mission will collect data about the asteroid Psyche. For this observation, you will use NASA’s Eyes on Asteroids interactive to get a 360-degree view of Psyche.

    • Have students explore the shape-model and artistic representation of asteroid Psyche by clicking and dragging the frame in NASA’s Eyes on Asteroids interactive. Note that no one has actually seen asteroid Psyche yet, which is one reason why the mission is so important to help us learn more.

    • Remind students to record their observations on their worksheet.
    • Have students share their observations with a partner or within their group and discuss benefits and limitations to this method of observation.
  7. Tell students they have now used four types of observations to gather information about distant objects in space. They now have tools to apply their knowledge and data to evaluate each observation type. With this knowledge, they can better understand the design of various NASA missions.


  • What did you learn from each type of observation?
  • Why would you use one over the other, evaluating the pros and cons of each? Some considerations could include the time and cost to build each type of observatory.
  • Why has NASA chosen a flyby mission to map asteroid Psyche and study its properties?
  • Which observation type would you use for the Psyche mission?
  • In addition to the four types of observations we learned about in this lesson, what other ways can be used to observe an object up close? Discuss landers and rovers.


  • Ask students to sign and submit their worksheets. Evaluate each to learn students’ observations, questions, and quality of observation data.
  • During students’ sharing of observations, circulate and listen to evaluate students’ knowledge. Scaffold as necessary.
  • During the final lesson discussion, listen to students to learn about their knowledge of observations and their ability to apply this knowledge to evaluate NASA missions.


  • Have students record their observations and evaluation of the types of observations and missions in their science journals.
  • Within their science journals, have students write about their experiences and which observation type they would choose if they needed to collect data about a distant object in space like asteroid Psyche.
  • Have students use NASA’s Eyes on Asteroids to observe additional asteroids and compare and contrast their features.

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This activity has been adapted from the Strange New Planet activity from Mars Education at Arizona State University.