The system includes two broad-beam, low-gain antennas on opposite sides of the spacecraft, used mostly for near-Earth communications; as well as a 30-centimeter (12-inch) diameter medium-gain dish antenna and a large, 2.1-meter (83-inch) diameter high-gain dish antenna. The antenna assembly on the spacecraft’s top deck consists of the high, medium, and forward low-gain antennas; this stacked design provides a clear field of view for the low-gain antenna and structural support for the high and medium-gain dishes. Operators aim the antennas by turning the spacecraft toward Earth. The high-gain beam is only 0.3 degrees wide, so it must point directly at Earth. The wider medium-gain beam (4 degrees) is used in conditions when the pointing might not be as accurate. All antennas have Right Hand Circular and Left Hand Circular polarization feeds.
Data rates depend on spacecraft distance, the power used to send the data and the size of the antenna on the ground. For most of the mission, New Horizons has used its high-gain antenna to exchange data with the Deep Space Network’s largest antennas, 70 meters across. Even at Pluto, because New Horizons will be more than 3 billion miles from Earth and radio signals will take more than four hours to reach the spacecraft, it can send information at about 1,000 bits per second. It will take 16 months to send the full set of Pluto encounter science data back to Earth.
New Horizons is flying the most advanced digital receiver ever used for deep space communications. Advances include regenerative ranging and low power – the receiver consumes 66% less power than earlier deep-space receivers. The Radio Science Experiment (REX) to examine Pluto’s atmosphere is also integrated into the communications subsystem.
Źródło:
http://pluto.jhuapl.edu/Mission/Spacecraft/Systems-and-Components.phpZ tego co tu jest napisane wynika, że pełna paczka danych będzie wysyłana przez 16 miesięcy.
