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Technology objectives
FROM NASA PRESS KIT Posted: August 9, 2005
The mission objectives for Mars Reconnaissance Orbiter do not end with the spacecraft's
scientific discoveries. It also has important work to do in relaying communications
from robots on Mars' surface and in demonstrating communication and navigation
technologies for use by future missions. Three instruments in the payload serve these
purposes:
Electra is a technology package enabling Mars Reconnaissance Orbiter to act as a
navigational and communications aid for other spacecraft as they approach Mars and
operate on the surface of Mars. It will use ultra-high frequency radio for relaying commands
from Earth to stationary and mobile robots on the surface and for receiving science
and engineering data to be relayed back to Earth via the orbiter's main antenna.
As spacecraft with compatible systems approach Mars, signals from the
Reconnaissance Orbiter's Electra will provide information about the arriving spacecraft's
speed and distance relative to Mars, allowing improved precision in landing.
Similarly, Doppler data from Electra communications, coupled with information about
the orbiter's position, can accurately indicate the position of a stationary lander or a
rover on the surface.
If either or both of the Mars Exploration Rovers Spirit and Opportunity are still operating
in the late 2006, they could be the first surface robots to use Mars Reconnaissance
Orbiter as a communications relay. The navigation and communications strategies for
the Phoenix Mars Scout mission, scheduled for launch in 2007, are being developed to
take advantages of the capabilities of Electra. Phoenix is slated to arrive at Mars in
May 2008 and land at a site in the arctic plains.
The Optical Navigation Camera is part of a technology demonstration of a navigation
technique. The demonstration will compare the predicted positions of Mars' two
moons, Phobos and Deimos, with this camera's observations of the moons as the
spacecraft approaches Mars. While this technique is not necessary for Mars
Reconnaissance Orbiter's own navigation, the demonstration will prepare the way for
relying on it for navigating precise arrivals for future missions that land on Mars. The
camera has an aperture of 6 centimeters (2.3 inches) and a narrow field of view of 1.4
degrees.
The Ka Band Telecommunications Demonstration will allow comparison of the
shorter-wavelength Ka radio band with the X band that is the standard for interplanetary
spacecraft communication with Earth and the primary band for this mission. The
Ka band equipment uses less power than its X-band counterpart to send the same
amount of data. However, Ka band transmissions are more susceptible to being disrupted
by water in Earth's atmosphere. Mars Reconnaissance Orbiter will use both
bands for sending data to Earth, providing a comparison that will aid planning of communication
systems for future interplanetary missions.
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