Voyager SCIENCE KIT Presentation Guide

DISPLAY IDEAS FOR SCIENCE FAIRS, CLASSROOM USE, CLUB ACTIVITIES, PLANETARIUMS, ETC.

Instructions for the Coordinator:

Instructions grouped on this sheet as "Tasks" are building blocks of ideas for accurate displays. Coordinator and Participants should modify them freely to suit individual circumstances, as well as invent new ones altogether. While this sheet was written by an instructional technologist for people working together in groups, nothing should prevent a single individual from working any or all of them alone.

Photocopy all the tasks on this sheet and cut them into individual Task-Cards. Also photocopy the Support Component diagram below. Assign one or two participants to each of the tasks, based on their preferences and abilities. Make sure each participant receives a copy of the appropriate card(s), and a copy of the Support Component diagram. Each group should also be armed with a dictionary. Have the participants thoroughly read and discuss their Task Cards before beginning work. The coordinator should assist participants by providing workspace and time, helping obtain materials, and suggesting sources of information.

The Support tasks are accomplished first. They provide components which will be used in the Demonstration Tasks to illustrate various modes of scientific space flight operations. Each group should sketch and discuss its Demonstration Task before starting work on it. Multiple displays may be set up at the same time by arranging to provide multiple support components. Alternatively, one set of support components may be rearranged repeatedly, say daily or weekly, to accomplish the demonstrations one at a time. Situations depicted in these displays use the Voyager spacecraft as an example, but they show operations which are typical of many different past and future space missions. These tasks touch the tips of a lot of icebergs, so to speak, and provide many opportunities for curious, motivated individuals to do further research. Use public and university libraries, and NASA Educational Outreach offices, for more information.

Support Tasks

(Complete these before starting the Demonstration Tasks.)

Support Task #1: The Voyager Spacecraft

Assemble one Voyager space craftª paper model according to the instructions provided. (Note that two models may be used, optionally, in Demonstration Task #8). Fashion a moveable tabletop stand with a heavy base which will allow some adjustment in the spacecraft's attitude. See the Support Components diagram. Attach the model's Scan Platform to the stand with wire or tape, so it can anchor the long piece of string or yarn called for in some Demonstration Tasks. Make an arrow labeled "DIRECTION OF FLIGHT" and tape it to the stand, pointing generally opposite the direction the antenna dish points. Plan to pin up the Voyager Spacecraft Description sheet provided with the kit.

Support Task #2: A ringed planet with a satellite

Obtain a globe-shaped object to represent a gaseous outer planet such as Saturn. The object should be large enough to suggest that the spacecraft can be completely hidden behind it. Cut a piece of cardboard to represent rings, sketch some concentric circles on it, and attach. Punch and mark hole "A" in the cardboard near an outer ring. Punch and mark hole "B" touching the sphere, about a quarter of the circle around from hole "A". Fashion a tabletop stand to set the planet on. Obtain a ping pong ball-size object to represent a satellite (such as Titan), and mount on a separate, moveable stand. Sizes are chosen for convenience and perspective, not scale. Color the spheres appropriately. (Saturn is pale, banded, and yellowish, and Titan appears light orange.)

Support Task #3: Sun, Earth, and two distant stars.

Obtain a ping pong ball-size object to represent the Sun, and a marble-size object to represent the Earth. Sizes are chosen for convenience and perspective, not scale. Color them appropriately: the sun bright yellow, the Earth blue and white. The Sun and Earth should be mounted about an inch apart, on one stand about a foot high, with a heavy base. Fashion two clearly visible stars which can be pinned to the display sidewalls. Optionally, make an enlargement of the solar system diagram from the Fact Sheet provided with the kit, to pin up.

Support Component Diagram

Note: Components are not to scale; sizes are chosen for ease in illustrating concepts.

Support Components Diagram

Demonstration Tasks

(These require completion of
Support Tasks #1 through 3)

Demonstration Task #4: Spacecraft Attitude Control

This demonstration shows how the Voyager spacecraft maintains its three-axis orientation in space. Refer to "Pitch, Yaw, and Roll" on the Spacecraft Description provided with the kit. The spacecraft's sun sensor monitors the relative position of the sun, while the Canopus star tracker monitors the relative position of a bright star located at about right angles to the Sun. The attitude control computer aboard the spacecraft uses these measurements to manage the firing of small monopropellent rocket engines mounted around the spacecraft, to continuously adjust its attitude. Normally, the spacecraft does this continuously to keep its dish-antenna pointed towards Earth for communication. During short periods when the Sun or star cannot be seen, such as when a nearby planet hides them, or when it is desirable to have the spacecraft turn away, the attitude control computer uses signals from a set of gyroscopes for reference.

Tasks #1, 2, and 3 should be finished. Make a sign for your display showing the above title. Attach a brightly colored string or yarn to the attitude reference star on the display sidewall. Run it to the Canopus star tracker on the spacecraft and attach (see spacecraft description provided with kit). Attach another color-coded string to the Sun. Run it through the hole in the front of the antenna dish, and attach it to the sun sensor just behind (see spacecraft description provided with the kit). Arrange the spacecraft so that the string to the Sun is straight, with the dish aimed at the Earth. Adjust the spacecraft , Sun, and Earth so that the string from the Canopus star tracker stretches straight to the attitude reference star, and both strings are straight and taut. Clear away all unused components. Write up a sign explaining the display, using information from this card and/or from outside references.

Demonstration Task #5: Remote Optical Sensing

This demonstration shows how the Voyager spacecraft makes observations with its five pointable optical instruments and returns the data toward Earth immediately via telemetry. (Data can also be recorded for later playback to Earth, as is the case when the spacecraft maneuvers to compensate for the relative motion of a target.)

Tasks #1, 2, and 3 should be finished. Make a sign for your display showing the above title. Refer to the Spacecraft Description provided with the kit to identify all of the optical instruments on the pointable scan platform. Attach a brightly colored string or yarn to the planet's satellite, and run it straight to the Imaging Science Narrow Angle Camera on the spacecraft. Take a paper ribbon and write a series of ones and zeroes along its entire length to represent computer communications. Run the ribbon from the spacecraft's dish antenna to the Earth (don't attach it to the sun sensor hole - it's used by another demonstration). Arrange the components so the Narrow Angle Camera is pointing to the satellite, and the antenna dish is pointing to the Earth. Make sure the path to Earth is clear. Clear away all unused components. Write up a sign explaining the display, using information from this card and/or from outside references.

Demonstration Task #6: Stellar Occultation of Rings

This demonstration shows how light from a distant star is monitored while it goes behind the rings of a nearby planet, as seen from the moving spacecraft. In this type of observation, the photopolarimiter instrument on Voyager's scan platform is used as a very sensitive light meter, measuring minute changes in the star's brightness as it blinks behind particles in a ring system. These measurements are radioed back to earth via telemetry, where they provide valuable data for studies of the ring system.

Tasks #1, 2, and 3 should be finished. Make a sign for your display showing the above title. Attach a brightly colored string or yarn to the distant star on the display floor or sidewall. Run it through Hole "A" on the ringed planet, and attach it to the photopolarimiter instrument on the spacecraft. Refer to the spacecraft description provided with the kit. The instrument should be pointing at the star (your component placing may differ from the Support Component Diagram). Arrange Hole "A" and the spacecraft in a straight line with the distant star. Adjust the components so that the string is taut and straight. Optionally, write the word, "TELEMETRY" repeatedly on a paper ribbon and extend it from the dish antenna to earth. Clear away all unused components. Write up a sign explaining the display, using information from this card and/or from outside references.

Demonstration Task #7: Radio Science Atmospheric Study

This demonstration shows how radio signals coming from the spacecraft are refracted (bent) by the nearby planet's atmosphere on their way back to Earth. They are also affected in other ways. The signals captured on Earth can be studied to provide much information about atmospheric structures, pressures, temperatures, and more. During such occultations, the spacecraft is programmed to transmit only the purest and steadiest radio signals possible. This way, the signals are stronger, and the atmosphere's effects on them can be seen more clearly, than if the signals were carrying telemetry. The spacecraft is carefully programmed to track the edge of the planet during this type of experiment. Spacecraft radio signals can similarly probe planetary rings, yielding valuable data for ring-system studies.

Tasks #1, 2, and 3 should be finished. Make a sign for your display showing the above title. Attach a brightly colored string or yarn inside the spacecraft's radio dish antenna (don't attach it to the sun sensor hole - it's used by another demonstration). Run the string through Hole "B" on the ringed planet, and attach it to the Earth. Arrange the centers of Earth, the ringed planet, and the spacecraft in a straight line, and aim the dish antenna right at hole "B." Keeping them in line, adjust the components so that the string is taut, and shows a noticeable bend around the planet. Clear away all unused components. Write up a sign explaining the display, using information from this card and/or from outside references.

Demonstration Task #8: Atmospheric Sun Occultation

This demonstration shows how an observation is made of the Sun as it sets into the atmosphere of a planet (or major satellite), when the spacecraft moves behind, and as it rises up through the atmosphere again when the spacecraft comes out from behind. Measuring the spectrum of sunlight provides valuable information about the composition, structure, and physical properties of the atmosphere. The ultraviolet spectrometer on Voyager's pointable scan platform is equipped with a specially-designed port to observe the Sun while the other instruments are pointed safely away. Since there are two identical Voyager spacecraft, the non-encountering one is normally commanded to observe the Sun simultaneously, from a different location unimpeded by a planetary system, in order to provide a control for analysis.

Tasks #1, 2, and 3 should be finished. Make a sign for your display showing the above title. Run a brightly colored string or yarn from the sun, and attach it to the ultraviolet spectrometer on the spacecraft's scan platform (refer to the spacecraft description provided with kit). Arrange the Sun and the spacecraft in a straight line. Set the planet or a satellite where it touches the string without bending it very much, and adjust the spacecraft to show movement behind the planet so that the Sun will appear to set into the atmosphere. Adjust the components so that the string is taut. Optionally, provide a second string (or rod) from the Sun indicating where sunrise will be observed as the spacecraft travels on. As another option, set up a second Voyager model, observing the Sun from afar with its ultraviolet spectrometer. Clear away all unused components. Write up a sign explaining the display, using information from this card and/or from outside references.

Permission is granted to reproduce this Presentation Guide for use with an associated SCIENCE KIT.
SCI Space Craft International, P.O. Box 61027, Pasadena, CA 91116-7027 USA