Apparatus, system and method for spacecraft navigation using extrasolar planetary systems

Abstract

The present invention provides an innovative apparatus, system and method for onboard spacecraft location determination and navigation by employing the observation of extrasolar planetary star system motion. In one apparatus embodiment a gas absorption cell is placed between a sensor and the light from a reference star system with at least one exoplanet, such that the sensor can detect the spectrum through the gas absorption cell. Radial velocities can be calculated via Doppler Spectroscopy techniques and incorporated into a spacecraft navigation solution. The present invention can enable and enhance significant mission capabilities for future manned and unmanned space vehicles and missions.

1 . A spacecraft extrasolar planetary star tracker apparatus, comprising:
 a sensor to detect a spectrum from a star system with at least one exoplanet; and   a gas absorption cell placed between the sensor and the star system with at least one exoplanet such that the sensor can detect the spectrum from the star system with at least one exoplanet through the gas absorption cell.   
     
     
         2 . The apparatus of  claim 1 , wherein the detected spectrum is used to calculate radial velocity via Doppler spectroscopy. 
     
     
         3 . The apparatus of  claim 1 , wherein the detected spectrum measurements are used to calculate spacecraft position. 
     
     
         4 . The apparatus of  claim 1 , wherein the detected spectrum measurements are accumulated and used to calculate a filtered estimate of spacecraft position. 
     
     
         5 . The apparatus of  claim 1 , wherein the star system with at least one exoplanet is used to calculate spacecraft attitude. 
     
     
         6 . A spacecraft navigation system using extrasolar planetary star motion comprising:
 a sensor located on a spacecraft to detect a spectrum from a star system with at least one exoplanet;   a gas absorption cell located on the spacecraft placed between the sensor and the star system with at least one exoplanet such that the sensor can detect the spectrum from the star system with at least one exoplanet through the gas absorption cell;   a computer located on the spacecraft that is connected to the sensor by a data bus;   a software algorithm located in the computer that can calculate radial velocities from the detected spectrum via Doppler spectroscopy techniques; and   a software algorithm located in the computer that can calculate spacecraft position using the calculated radial velocities from the detected spectrum.   
     
     
         7 . The system of  claim 6 , wherein the computer has an additional software algorithm that is used in the process of controlling the velocity of the spacecraft. 
     
     
         8 . The system of  claim 6 , wherein the calculated radial velocities are accumulated and used to calculate a filtered estimate of spacecraft position. 
     
     
         9 . The system of  claim 6 , wherein the software algorithm that calculates spacecraft position uses a Kalman filter. 
     
     
         10 . The system of  claim 6 , wherein the software algorithm that calculates spacecraft position includes additional navigation sensor measurements. 
     
     
         11 . The system of  claim 6 , wherein the star system with at least one exoplanet is used to calculate spacecraft attitude. 
     
     
         12 . The system of  claim 6 , wherein there is more than one sensor for the purposes of detecting different star system spectrum simultaneously. 
     
     
         13 . A method for onboard spacecraft navigation using extrasolar planetary star systems, the method comprising the steps of:
 having an initial estimate of a spacecraft position in an inertial reference frame;   selecting a reference star system with at least one exoplanet from an onboard software database;   detecting a spectrum from the reference star system with at least one exoplanet through a gas absorption cell onboard the spacecraft;   using the detected spectrum from the reference star system with at least one exoplanet to calculate radial velocity via Doppler spectroscopy; and   incorporating the radial velocity calculations and the initial estimate of spacecraft position into a filtered estimate of spacecraft position.   
     
     
         14 . The method of  claim 13 , wherein the means for filtering include a Kalman filter. 
     
     
         15 . The method of  claim 13 , wherein the filtered estimate of spacecraft position includes additional navigation sensor measurements. 
     
     
         16 . The method of  claim 13 , wherein the filtered estimate of spacecraft position includes Global Positioning System measurements. 
     
     
         17 . The method of  claim 13 , wherein the filtered estimate of spacecraft position includes Deep Space Network measurements. 
     
     
         18 . The method of  claim 13 , wherein onboard spacecraft navigation is used in the process of controlling the velocity of the spacecraft. 
     
     
         19 . The method of  claim 13 , wherein the reference star system with at least one exoplanet is also used to calculate spacecraft attitude. 
     
     
         20 . The method of  claim 13 , wherein onboard spacecraft navigation is used in the process of controlling the attitude of the spacecraft.