Design for a Deep Space Communications System

The discourse system result comprise of a redundant dual-band transmission channel, namely an S-band system and an X-band system. The S-band system allow be designed specifically for providing tracking, telemetry and control, while the X-band will be used exclusively for telemetry and scientific data. These systems will operate within their condition ranges (S-band transmit 2290-2300 MHz, receive 2110-2120 MHz, X-band transmit 7145-7190 MHz, receive 8400-8450 MHz1) as would be specified by the ____Governing body____.The basic mission requirements and assumptions have changed since the general specifications laid out in Assignment 3, primarily that the satellite must land on, or come in contact with, the comet at some item rather than perform a fly-by. With this in mind, the individual components that will be used on the communication theory system are detailed in the following sectionsAntennasThere will be both an omnidirectional S-band helical antenna2, specifically desig ned for telemetry and reign overs, as well as a 2.2 metre high-gain antenna3, akin to the Rosetta satellite antenna. This antenna has optimal performance within both S- and X-band frequencies and both are manufactured by RUAG blank shell AG, based in Switzerland.TransponderThe system will incorporate two redundant small deep-space transponders (SDSTs) 4, developed by General Dynamics and NASAs Jet Propulsion Laboratory. This device combines a number of communication functions receiver, command detector, telemetry modulator, exciter, beacon generator and control functions all into one package. This transponder has Ka-band capability as well for future missions, which comprises of a second X-to-Ka band multiplier.Envelope Size 7.13L x 6.55W x 4.50H pack 7.0 lbs (3.2 kg)Input Supply PowerReceiver Only 12.5 WReceiver + X-band Exciter 15.8 WAmplifiersTwo 17 W, 8.4 GHz solid-state power amplifiers5, manufactured by General Dynamics will be enforced as small, lighter and less expensiv e alternative to the traveling-wave-tube X-band amplifier. These amplifiers are designed for use as a companion unit to the SDST and can supply telemetry signals that can be connected directly to the SDST to make a complete transmitter/receiver with a single data interface.Maximum dimensions 6.85L x 5.275W x 1.85HMass 3.02 lbs (1.37 kg)Data interface MIL-STD-1553B data interfaceOther componentsOther smaller components include a diplexer, attached to the high-gain amplifier, which will allow the S- and X- band transmitter to use the same antenna, as well as allowing the antenna to be used for transmissions on one band and receive on another band. The system will also require a coupler to assign the amplifiers to the respective antennas as well as a hybrid coupler betwixt the amplifiers and the transponders to allow each transponder to drive either amplifier without requiring active switching.Issues in Deep Space CommunicationsCompared with normal satellite communications, deep-spac e communications present a significant challenge specifically from the distance resulting in low signal-to-noise ratio, propagation delays, corruption as well as environmental factors such as temperature variations and electromagnetic radiation. The satellite will be evanescent behind the Sun for a period of time, it is important to note that communication will be mask for a substantial period of time. One possible solution is to take advantage of NASAs stereo system (Solar TERrestrial Relations Observatory) satellites in orbit around the sun to provide a link between the satellite-comet intercept point and Earth while the satellite is obscured.