Lesson: How Can A Spacecraft Always Face The Sun?

(Grades 6-8)

Teacher Information

NASA launched the SOHO (Solar and Heliospheric Observatory) spacecraft on December 2, 1995. It orbits the Sun with the Earth, but faces the sun continuously. It provides an uninterrupted view of the Sun 24 hours a day because its orbit never takes it behind the Earth. The orbital path is around the L1 Lagrangian point where the gravitational pull from the Earth equals the gravitational pull from the Sun. SOHO is 1,500,0000 km from the Earth in a straight line path between the Earth and the Sun.

The objective of this lesson is to have the students figure out where a spacecraft like SOHO could be placed to meet the established criteria. When the activity is complete the teacher can then introduce them to SOHO. Students should not be introduced to SOHO prior to this lesson.

Prerequisites: Students should be familiar with -

Activity: How Can A Spacecraft Always Face The Sun?

(A critical thinking and decision-making activity for grades 6 - 8)


Type of Activity


  1. Divide class into teams of 3 - 4 students each.
  2. Have the teams select team members to fill these positions on the team:
  3. Assign the task: NASA wants to place a spacecraft in orbit which will orbit the Sun with the Earth. The spacecraft must also face the Sun continuously and never be behind the Earth where its view of the Sun could be blocked. Your job as a team is to determine how the spacecraft's orbit could meet the criteria established by NASA. Notes, etc. on spacecraft orbits, placing spacecraft in orbit, and Lagrangian Points may be used. Model building is encouraged.
  4. Students do brainstorming. All ideas are accepted and listed during this time. Students should be reminded that the merits of the ideas are not to be discussed during the brainstorming session.
  5. Students discuss the merits of each idea and eliminate those they determine are not feasible. Encourage teams to make models of their orbital designs during this "weed-out" session. This step may take several days to complete.
  6. Students make their decision on which design is best. They should record why they discarded some ideas and why they think the chosen design is the best one.
  7. Teams present their designs to the class.
  8. Compare student designs to SOHO's orbit.


How Far Away Is SOHO?

Connections to National Standards:

Created by:Betty Harris
Direct comments to:eaharris@lcmr.capemayschools.com
Last Modified Sept. 29, 1998