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Exploration through Navigation
Charting a Course to the Moon

Preliminary Design by:
Ms. Rogers

Navigation plan: Earth to Moon
Team Name: Team AstROOnaut (Julian, Mosier Oregon)

Spacecraft name: Wall-e-ROO

Launch Time and Date: January 26th, 2009 (Australia Day)

Duration of Journey: 98 days approximately. We got this number based on a 3 day flight from the Earth to the Moon (like Apollo flights) and then the spacecraft doing a slingshot around the Moon and into an LGALRO orbit. Each LGALRO orbit takes 38 days and 2 ½ orbits are needed. That makes the total travel time 98 days.

Description of Route and Orbital Path:

Launch is from Cape Canaveral. Once the probe is on the opposite side to the moon, the boosters are fired to go into the transfer orbit to the moon. The escape velocity that is needed to be reached is 7 miles per second or about 25,000 miles per hour.

Using the gravity of the Moon and Earth, the spacecraft will slingshot into an LGALRO orbit. This orbit is needed because it is faster and higher energy than the one used by the Apollo crews. This orbit uses less fuel and is a highly elliptical orbit going around both the Earth and the Moon. After 98 days, the spacecraft will have a high energy impact almost perpendicular to the lunar surface. This angle allows lots of Moon dust to fly everywhere.

Navigation Instruments:

Earthlings can monitor the spacecraft’s path and velocity with radio signals. A Deep Space Network of giant radio antennas use something called Doppler Shift. Computers on the spacecraft and on Earth are also used.

Methods of guidance, navigation, control, and tracking:

Radio signals are sent from the Moon-bound spacecraft and are received on Earth by giant radio antennas of something called the Deep Space Network. The speed of the craft is calculated using Doppler shift. Doppler shift is the apparent change in frequency of the sound or light waves emitted by the spacecraft measured from antennas on Earth.

The spacecraft position in the sky can be calculated by two or more antennas at DSN stations at opposite end of the Earth. The antennas make recordings of the spacecrafts radio signals then are turned towards a quasar, whose location is known with accuracy, and by comparing the two radio signals can determine the spacecrafts location in the sky.

Accurately knowing the spacecrafts position and velocity , NASA can decide whether on not to make corrective firings of the rockets onboard the spacecraft. If the rockets need to be fired, NASA can relay the information needed to fire the rockets via the DSN.
Thanks in advance for any advice.

 FirstGov  NASA

Editor: Linda Conrad
NASA Official: Liza Coe
Last Updated: October 2007
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