Co-orbiting laser communications relay satellite

Abstract

A dedicated satellite to reduce the cost and increase the rate and reliability of data transmission from space to ground is provided. For each client satellite producing data in Earth orbit, a dedicated relay satellite is provided. The relay satellite may fly near the client satellite and receive data from the client satellite by RF communication. The relay satellite may transmit the data to a ground terminal or to another satellite using a laser communication system. Because the relay satellite is not physically connected to the client satellite, the attitude-control requirements of an optical communication system are not imposed on the client satellite. The relay satellite may also be deployed from the client satellite. The relay satellite may allow downlinking large amounts of data for new satellite operators without an existing ground network and for established satellite operators seeking higher data rates, lower latency, or reduced ground system operating costs.

1 . A relay satellite for relaying data from a client satellite to thereby reduce power and pointing accuracy requirements of the client satellite, said relay satellite comprising:
 a short-range communications link configured to receive data from the client satellite; and   a long-range communications link configured to retransmit the received data to a ground station or another satellite,   wherein the relay satellite is deployed in one of (a) a quasi-orbit with respect to the client satellite such that the relay satellite and the client satellite can be kept within a pre-determined distance or (b) the same orbit as the client satellite but with an in-track offset that keeps the relay satellite and the client satellite within a pre-determined distance;   wherein the short-range communications link can be used to receive data from the client satellite when the client satellite is within a pre-determined distance of the relay satellite.   
     
     
         2 . The relay satellite of  claim 1 , wherein the short-range communication link is a radio communication link. 
     
     
         3 . The relay satellite of  claim 2 , wherein the radio communications link receives data on a radio communication band specified for the client satellite to transmit data to ground. 
     
     
         4 . The relay satellite of  claim 1 , wherein the long-range communications link is a laser communication transmitter. 
     
     
         5 . The relay satellite of  claim 1 , further comprising a memory for storing the received data, wherein the received data is retransmitted when the relay satellite passes over a ground station. 
     
     
         6 . The relay satellite of  claim 1 , wherein the received data is retransmitted to another relay satellite. 
     
     
         7 . The relay satellite of  claim 1 , wherein the relay satellite is a CubeSat. 
     
     
         8 . The relay satellite of  claim 1 , wherein the quasi-orbit passes between the client satellite and Earth. 
     
     
         9 . The relay satellite of  claim 1 , wherein the quasi-orbit is elliptical. 
     
     
         10 . The relay satellite of  claim 1 , wherein the quasi-orbit has a different inclination than an orbit of the client satellite. 
     
     
         11 - 14 . (canceled) 
     
     
         15 . A method of relaying data using a relay satellite to thereby reduce power and pointing accuracy requirements of the client satellite, comprising:
 deploying the relay satellite in one of (a) a quasi-orbit with respect to the client satellite such that the relay satellite and the client satellite can be kept within a pre-determined distance or (b) the same orbit as the client satellite but with an in-track offset that keeps the relay satellite and the client satellite within a pre-determined distance;   the relay satellite receiving data from a client satellite via a radio communications link; and   transmitting the received data from the relay satellite to a ground station or another satellite using an optical communication link;   wherein the short-range communications link can be used to receive data from the client satellite when the client satellite is within a pre-determined distance of the relay satellite.   
     
     
         16 . The method of  claim 15 , further comprising:
 storing the received data in a memory, wherein the transmitted data is the data stored in memory.   
     
     
         17 . The method of  claim 16 , wherein the data transmission is begun when the network satellite is over the ground station. 
     
     
         18 . The method of  claim 15 , wherein the direction of the optical communication link is distinct from the direction of observation of an instrument of the client satellite. 
     
     
         19 . (canceled)