《卫星工程》英文版（一） l2_orbital_mech

Outline Launch systems characteristics Launch systems selection process Spacecraft design envelope environments

Earth Orbiting Clusters Edmund M C Kong SSL Graduate Research Assistant Prof david w. miller Director, MIT Space Systems Lab Space 2001 Conference& Exposition Albuquerque August28-30,2001

Overview lecture Space Systems Engineering presented by: Prof David Miller prepared by: Olivier de Weck Revised and augmented by: Soon-Jo Chung Chart: 1 16.684 Space Systems Product Development February 13, 2001

ADCS Motivation Motivation Sensors GPS star trackers. limb In order to point and slew optical sensors rate gy ros. inertial systems, spacecraft attitude control measurement units provides coarse pointing while

The TCP/P Protocol Suite Transmission Control Protocol Internet protocol Developed by darPa to connect Universities and Research Labs Four Layer model Applications Telnet, FTP, email, etc Transport TCP, UDP Network IP ICMP, IGMP Link

Packet Multiple Access SHARED UPLIN TERMINAL APPL TERMINALL TRANS NET LLC DLC MAC

Automatic repeat request (ARQ) Break large files into packets FILE PKT PKT PKT Check received packets for errors Use a feedback channel to request retransmissions Retransmit packets containing errors acket Receive ACK

Routing Must choose routes for various origin destination pairs o/d pairs) or for various sessions Datagram routing: route chosen on a packet by packet basis Using datagram routing is an easy way to split paths Virtual circuit routing: route chosen a session by session basis Static routing: route chosen in a prearranged way based on O/D pairs Eytan Modiano

CSMA/CD and Ethernet Two way cable wsws Ws W CSMA with Collision Detection(CD)capability Nodes able to detect collisions Upon detection of a collision nodes stop transmission Reduce the amount of time wasted on collisions Protocol