- Radio Science Subsystem
The Radio Science Subsystem (RSS) is a spacecraft science instrument. Using various
microwave generators the RSS sends out clean signal that ground antennas detect or it may receive signals from earth orbiting Deep Space Network, amplify the signal and resend the signal back. The basic principle of the device is to measure, from a passing satellite or spacecraft, the behavior of some intermediate object by receiving and/or sending pulses of energy to a fixed network of receivers (on or close to Earth). For the most part the RSS is not an independent science instrument, much of what RSS does can be done through the telecommunications receiver/transmitter and radiotelescope. More advanced spacecraft have filtering and polarization capabilities added to the telecommunications receiver/transmitter. Acculation or Radio Accultation also refers to radio science in that acculation of the satellite as is passes behind mars with respect to earth, the is the optimal opportunity for Radio Science Observations.Spacecraft using RSS
*Cassini–Huygens [ [http://saturn.jpl.nasa.gov/spacecraft/instruments-cassini-rss.cfm Cassini-Huygens: Spacecraft-Instruments-Radio Science Subsystem (RSS)] Ulysess - European Space Agency]
*Mariner 2 , 4,5,6,7,9, and 10
*Voyager 1 and 2
*MESSENGER [Srinivasan DK, Perry ME, Fielhauer KB, Smith DE and Zuber MT. "The Radio Frequency Subsystem and Radio Science on the MESSENGER Mission". 2007. Space Science Reviews 131 :557-571doi|10.1007/s11214-007-9270-7]
*Venus Express Functions
* Determine composition of gas clouds such as atmospheres, solar coronas.
* Characterize gravitational waves
* Estimate masses of celestial satellites that do not have satellites of their own.
* To estimate particle size of particle fields
* Estimate densities of ion fields. [ [http://ulysses.esa.int/science-e/www/object/index.cfm?fobjectid=34954&fbodylongid=1623 Instruments - RSS: Radio Science Subsystem] Cassini-Huygens, ESA]pecifications
* Given a
deep space network (DSN) of receivers and/or transmitters.
*A Ka-band traveling wave tube amplifier (K-TWTA) amplifies signals to a transmitting antenna to be received by a distal radio- telescope.
*Ka-band translator (KAT) receives signal from a high-gain antenna and retransmits the signal back to DSN. In this way the phase and phase-shift resulting from signal modification
*Ka-band exciter (KEX) it supplies telemetry data.
*S-band transmitter is used for radio science experiments. The transmitter receives signal from the RFS, amplifies and multiplies the signal, sending a 2290 MHz signal to the antenna.
*Filter microwave emitter allow only microwaves of a given frequency to be emitted, there is a polarizing element. There are two-bypass filters and a wave-guide. The bypass filters allow different feed polarizations, receiving and transmitting.Confusing Terminologies
References
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