Magellan Presentation Guide

The Magellan 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 and educational displays. Coordinator and Participants should modify them freely to suit individual circumstances, as well as invent new ones altogether. While this sheet was written 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. Assign two or more participants to each of the tasks, based on their preferences and abilities. Each participant should read the Fact Sheet containing Highlights of the Magellan Mission and the Magellan Spacecraft Description. Give each participant a copy of the appropriate card(s). Each group should also be armed with a good 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 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 in these displays depict Magellan operations. Some of these operations are typical of 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 and materials.

Support Tasks
(Complete these before starting the Demonstration Tasks.)

Support Task #1:
The Magellan Spacecraft
Assemble one Magellan Space Craft SCIENCE KIT model according to the instructions provided. For added realism, do "OPTION 1: ARTICULATED SOLAR PANELS" in the assembly instructions. If you choose to do Demonstration Task #4 or 5, you'll need to accomplish "OPTION 2: SOLID ROCKET MOTOR". Fashion a moveable tabletop stand for your completed spacecraft model, with a heavy base, which will allow some adjustment in the spacecraft's attitude. Make an arrow labeled "DIRECTION OF FLIGHT" to be taped to the stand in various directions. Plan to pin up the Magellan Spacecraft Description sheet provided with the kit.

Support Task #2:
Sun, Earth, and two distant stars
Obtain a ping pong ball-size object to represent the Sun, and one 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 will need to be moved to convenient locations for some Demonstration Tasks, perhaps attached to the walls near your display. Fashion two clearly visible stars which can be pinned to the walls. In the Demonstration Task Displays, arrange the Sun, if possible, to be where it would shine straight on toward the spacecraftÕs solar panels.

Support Task #3:
The Planet Venus
Obtain a basketball-size object to represent the planet Venus. Size is chosen for convenience and perspective, not scale. Color it appropriately; Venus is entirely covered with bright white clouds. For one of the Demonstration Tasks, a flat tabletop will be used to represent the surface of Venus. If you want to add more detail, you might use a 3-D plastic relief-map which has been spray-painted grey.

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

Demonstration Task #4:
Deployment from Atlantis
This demonstration shows how the Magellan spacecraft was deployed from the Space Transportation System (Shuttle) orbiter Atlantis . You'll have to cut the solar panels off the model and re-arrange them. You'll also need a photograph of a Space Shuttle Orbiter in Earth orbit, preferably with payload bay doors open and bay empty. A 1/30 scale or smaller Shuttle Orbiter Model would suffice.) Also provide a 355ml /12-ounce aluminum soft-drink can to represent an IUS.

Tasks #1 and 3 should be finished. Fashion the SRM described in Option 2 of the instructions, and secure in place with glue. Cut the solar panels off your model at a point 1cm or 3/8 inch inboard from each panel. Re-join the panels to the support arm at 90 degrees, as if they had been folded down, with the blue/silver side facing outward, and the white side touching the rocket engine modules. Secure them in place with glue. Spray the aluminum can white. For extra detail, put 1cm letters USA to the side, about in the middle; paint a 2cm-high band of gold around the can, about 1/2cm up from the bottom. Complete the "IUS" with a gold, cone-shaped nozzle about 3cm long at the bottom of the can. Set the Magellan spacecraft and SRM atop the IUS and secure with glue. For extra realism, add six V-shaped white struts joining the top edge of the can to MagellanÕs REM LOWER SUPPORT ring.

Arrange the Magellan/IUS in relation with your Shuttle Orbiter photo or model to suggest that it has been released from the Orbiter Bay, and is adrift nearby. Clear away all unused components. Write up a sign explaining the display, using information from the first part of "Highlights of the Magellan Mission to Venus" included with the kit, and/or from outside references.

Demonstration Task #5:
Venus Orbit Injection
This demonstration shows how the Magellan spacecraft, approaching Venus from Earth, slowed down and entered into orbit around Venus by firing the Solid Rocket Motor (SRM) which was attached to the spacecraft.

Tasks #1, 2, and 3 should be finished. Fashion the SRM described in Option 2 of the instructions, and secure in place with glue. Arrange the spacecraft, Venus, and Earth so that 1) the Medium Gain Antenna is pointing to Earth, 2) the spacecraft is about a foot from the planet, over behind its north pole as viewed from Earth, and 3) its long axis is roughly tangent to Venus's surface. The SRM nozzle will be pointing in the direction of motion. If you have included Option 1, ARTICULATED SOLAR PANELS, they would be positioned with their edges in line with spacecraft's long axis.

Shortly after the spacecraft plunged over Venus's north polar region, it was occulted from EarthÕs-view behind Venus. At that time the SRM was ignited, and it successfully burned for 83 seconds. As it burned, the spacecraft's attitude was controlled by bursts from its set of 445N and 25N liquid-fueled thrusters. The spacecraft decelerated enough to enter into orbit around the planet, where it will remain indefinitely. Shortly after SRM burned, it was separated from the spacecraft, and it probably still orbits Venus.

As an option, you could illustrate the rocket engines' exhaust with crepe-paper flames: a large plume from the SRM, and some very small ones from the thrusters. Clear away all unused components. Write up a sign explaining the display, using information included with the kit, and/or from outside references.

Demonstration Task #6:
Normal Mapping
This demonstration shows how the Magellan spacecraft uses Synthetic Aperture Radar (SAR) and Altimetry which will form a detailed map of the surface of Venus. Refer to Fact Sheet Figure 2, positions 1,2,3,4, and 5.

Tasks #1 and 2 should be finished. The surface of Venus should be represented by a table-top, or other makeshift arrangement to represent the surface of Venus. Make a sign to label it as such. Position the model a couple feet above the surface, with its altimeter antenna pointing straight down. If the model has OPTION 1: ARTICULATING SOLAR PANELS, aim them toward the sun in your display. Position the DIRECTION OF FLIGHT arrow or sign so it points in the same direction as the STAR SCANNER is pointing. Connect a brightly colored piece of string or yarn from the altimeter antenna straight down to the surface. Indicate with a sign that it is measuring the height of the terrain. Run another colored string or yarn from the high-gain dish antenna to the surface, straight out of the dish and hitting the surface at an angle. Label it RADAR PULSE. Now run two strings of the same color from the point where the radar pulse hits the ground. One should go back up to the spacecraft's flight path, behind the spacecraft. and the other should go up to the path of flight ahead of the spacecraft. This represents the fact that as the radar pulse hits the surface, it bounces back in all directions. Some of those signals are picked up as the spacecraft moves ahead in its flight path, thus synthesizing a larger receiving area than the size of its dish alone. Write up a sign for your display explaining this, and include other information as appropriate from this package or from other sources. Clear away any unused components.

Demonstration Task #7:
Communicating with Earth
This demonstration shows the Magellan spacecraft transmitting data back to Earth, after having collected it during the mapping portion of an orbit and storing it on its tape recorders. Refer to Fact Sheet Figure 2, positions 6,7,8, and 10.

Tasks #1, 2, and 3 should be finished. Position the spacecraft on the earth-side of Venus, at a distance of a couple of feet from Venus, and its antenna dish pointed toward Earth about 3Ñ5 feet away. Extend a brightly-colored string or yarn between the spacecraft and the Earth, and label it DATA FROM THE SPACECRAFT. Optionally, run two differently colored strings, and label one COMMAND DATA TO THE SPACECRAFT, Position the Sun and solar panels to illustrate the sun shining on the panels. Write up a sign for your display explaining this part of Magellan's mapping orbit, and include other information as appropriate from this package or from other sources. Clear away any unused components.

Demonstration Task #8:
Attitude-Control Star Calibration
This demonstration shows how the Magellan spacecraft updates its knowledge of its three-axis orientation in space. Refer to Fact Sheet Figure 2, position 9. Attitude refers to the orientation of the spacecraft in space - which way it is pointing. Precise attitude knowledge permits pointing the radar and altimeter correctly for mapping, and pointing to Earth for communications.

The spacecraft updates its attitude data by performing a maneuver once in every orbit. First the spacecraft maneuvers to a predetermined attitude, from which two carefully selected stars will be visible. Next spacecraft turns slowly about its roll axis, that is the axis in which the dish antenna points. During the roll turn, the star tracker observes the two stars as they pass across its field of view. The attitude control computer aboard the spacecraft makes exact measurements of the directions to these stars. It uses these measurements to make any necessary corrections to its precise attitude knowledge.

Tasks #1, 2, and 3 should be finished. Arrange the spacecraft as in Task #7, but with the antenna dish not pointed toward Earth. Have the Sun on the opposite side of the spacecraft from the star tracker. Attach a brightly colored string to a star on the display sidewall. Run it to the star tracker on the spacecraft and attach. This represents the first star which the star tracker senses in the maneuver. Place another star on the display sidewall to indicate the next star the tracker will view as the spacecraft makes a roll turn of about 50 degrees (either direction). Arrange the spacecraft so that both strings are straight. Clear away all unused components. Write up a sign explaining the display, using information from this card and/or from outside references.