Exploration through Navigation
Charting a Course to the MoonPreliminary Design by:
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
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
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.
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.