All spacecraft need to know where to go and have a way to get there. The "map" the spacecraft follows is based on celestial navigation; it steers by looking at the stars (__). Using propellant (__), the spacecraft moves around in 3-dimensional space by spewing fluid through nozzles at high speeds (__) oriented in 3 different directions. The power needed to operate the instruments and computers onboard is generated from the heat of radioactive sources (__). The hot environment (extreme temperatures, unfiltered sunlight , etc.) encountered during the trip to Venus on the way Jupiter required extra protection in the form of __. Communication (__) between the spacecraft and Earth is one of the key challenges we have to face because the High-gain Antenna did not open properly during flight (the shape shown above is what we think it looks like...it was supposed to unfold so that it would look like an upside-down umbrella) and thus we must rely on other equipment and new data-handling techniques for communication. Upon Jupiter arrival, the Atmosphere Probe will send data to the Galileo Orbiter using a dish (__) oriented toward the planet (and away from the Earth).
Spacecraft have 2 ways of moving using thrusters. One way, called "Turn & Burn", is to turn the
spacecraft so that its thrusters are pointing along the direction we want it to go:
During "Turn & Burn" maneuvers we often lose communication with the spacecraft because its antenna is not pointed towards Earth.
Another choice is doing a "Vector" maneuver. This maneuver involves doing burns in 2 different directions to get the spacecraft going the correct way:
Draw a 10 by 10 square grid on the ground using chalk or use floor tiles. Designate a few students to be planets and have them stand on different parts of the grid. Make up a list of planets and an order in which to visit them. Review this list with a designated "human spacecraft" before he or she begins their "Planetary Tour". For the "Vector mode" Tour, the spacecraft can only move along the grid lines. The spacecraft is allowed to talk to "home" (i.e., ask the teacher for directions). Count the number of steps used during the Tour.
Re-create the Tour in "Turn & Burn" mode by walking directly toward each planet in the same order. The spacecraft is not allowed to "phone home" for directions. Count the number of steps used and subtract from it the number of steps used during the "Vector" Tour...this is the amount of "propellant" saved.
Did the spacecraft get lost during the second Tour? Can the students think of ways to save propellant AND "phone home" periodically?