System and method for assisted extravehicular activity self-return

Abstract

A system and method for assisted EVA self-return is provided herein. The system estimates a crewmember's navigation state relative to a fixed location, for example on an accompanying orbiting spacecraft, and computes a guidance trajectory for returning the crewmember to that fixed location. The system may account for safety and clearance requirements while computing the guidance trajectory. According to at least one embodiment, the system provides a directional cue (e.g., a visual, auditory, or tactile cue) to a crewmember corresponding to the prescribed trajectory back to the fixed location. The system may be activated by the crewmember or remotely by another crewmember and/or system.

What is claimed is: 
     
         1 .- 2 . (canceled) 
     
     
         4 .- 24 . (canceled) 
     
     
         25 . A self-return system comprising:
 a sensor configured to monitor a parameter of a suit;   a navigation module in communication with the sensor, the navigation module configured to:
 identify, based on parameter information received from the sensor, a current location of the suit in relation to a fixed reference point; 
 communicate with a suit system; and 
 initiate a self-return mode of operation in response to receiving a signal from the suit system; 
   a guidance module in communication with the navigation module, the guidance module configured to receive, in the self-return mode of operation, an indication of the current location of the suit from the navigation module and to compute, in response to receiving the indication of the current location of the suit from the navigation module in the self-return mode of operation, a trajectory from the current location of the suit to the fixed reference point; and   an output module in communication with the guidance module and configured to receive, in the self-return mode of operation, the trajectory from the guidance module and provide, in response to receiving the trajectory from the guidance module in the self-return mode of operation, a directional cue identifying a direction in which the suit should be propelled such that the suit is returned to the fixed reference point along the computed trajectory.   
     
     
         26 . The self-return system of  claim 25 , wherein the directional cue provided by the output module is a visual cue and the output module comprises a display device configured to display, in the self-return mode of operation, the visual cue identifying the direction in which the suit should be propelled such that the suit is returned to the fixed reference point along the computed trajectory. 
     
     
         27 . The self-return system of  claim 26 , wherein the display device is configured to be coupled to the suit and to display the visual cue to a user inside the suit. 
     
     
         28 . The self-return system of  claim 25 , wherein the directional cue provided by the output module is an auditory cue and the output module comprises an auditory output device configured to output, in the self-return mode of operation, the auditory cue identifying the direction in which the suit should be propelled such that the suit is returned to the fixed reference point along the computed trajectory. 
     
     
         29 . The self-return system of  claim 25 , wherein the directional cue provided by the output module is a tactile cue and the output module comprises a tactile output device configured to output, in the self-return mode of operation, the tactile cue identifying the direction in which the suit should be propelled such that the suit is returned to the fixed reference point along the computed trajectory. 
     
     
         30 . The EVA self-return system of  claim 25 , wherein the sensor comprises a gyroscope configured to monitor angular movement of the suit. 
     
     
         31 . The EVA self-return system of  claim 25 , wherein the sensor comprises an accelerometer configured to monitor linear acceleration of the suit. 
     
     
         32 . The EVA self-return system of  claim 25 , wherein the sensor comprises a vision+inertial sensor configured to measure angular movement of the suit, measure linear acceleration of the suit, capture visual images within a field of view of the vision+inertial sensor, and compensate the measured angular movement of the suit and the measured linear acceleration of the suit for drift based on the captured visual images. 
     
     
         33 . The EVA self-return system of  claim 25 , wherein the sensor comprises a Global Positioning System (GPS) device configured to communicate with satellites within a line of sight of the GPS device and determine a relative position of the suit based on the communication with the satellites. 
     
     
         34 . The EVA self-return system of  claim 25 , wherein the sensor comprises a Wi-Fi positioning system (WPS) configured to determine a relative position of the suit based on communication with a wireless access point. 
     
     
         35 . The EVA self-return system of  claim 25 , wherein the sensor comprises a star tracker system configured to capture visual images of objects within a field of view of the star tracker system, compare the captured visual images of the objects to images of the objects previously stored in a database, and determine a relative position of the suit based on the comparison of the captured visual images of the objects to the previously stored images of the objects. 
     
     
         36 . The EVA self-return system of  claim 25 , wherein the suit system is a user control system and the navigation module is further configured to initiate the self-return mode of operation in response to receiving the signal from the user control system. 
     
     
         37 . The EVA self-return system of  claim 25 , wherein the suit system is a communications system and the navigation module is further configured to initiate the self-return mode of operation in response to receiving the signal from the communications system. 
     
     
         38 . The EVA self-return system of  claim 25 , wherein the suit system is a biomedical monitoring system and the navigation module is further configured to initiate the self-return mode of operation in response to receiving the signal from the biomedical monitoring system. 
     
     
         39 . The EVA self-return system of  claim 25 , wherein in computing the trajectory from the current location of the suit to the fixed reference point, the guidance module is further configured to account for a predefined constraint. 
     
     
         40 . The EVA self-return system of  claim 39 , wherein the predefined constraint includes at least one of a volumetric envelope of the suit, a safety requirement, an external clearance requirement, and a geometry of a vehicle including the fixed reference point. 
     
     
         41 . The EVA self-return system of  claim 25 , further comprising:
 an interface configured to be in communication with a propulsive system; and   a control module in communication with the guidance module and configured to be in communication with the propulsive system via the interface,   wherein the navigation module is in further communication with the control module and is further configured to:
 determine, in response to initiating the self-return mode of operation, based on the parameter information received from the sensor, whether the suit is tumbling; and 
 in response to determining that the suit is tumbling, instruct the control module to transmit instructions to a propulsive system that are configured to operate the propulsive system such that the tumbling of the suit is nulled. 
   
     
     
         42 . A method for EVA self-return, the method comprising:
 monitoring a parameter of a suit;   continuously identifying, with a navigation module based on the monitored parameter information, a current location of the suit in relation to the fixed reference point;   initiating, in response to receiving a signal from a suit system, a self-return mode of operation;   computing, in the self-return mode of operation with a guidance module in response to receiving the current location of the suit from the navigation module, a trajectory from the current location of the suit to the fixed reference point; and   providing, in the self-return mode of operation with an output module in response to receiving the trajectory from the guidance module, a directional cue identifying a direction in which the suit should be propelled such that the suit is returned to the fixed reference point along the computed trajectory.   
     
     
         43 . The method of  claim 42 , wherein computing the trajectory includes computing the trajectory from the current location of the suit to the fixed reference point while accounting for at least one predefined constraint. 
     
     
         44 . The method of  claim 42 , wherein providing the directional cue comprises displaying a visual cue identifying the direction in which the suit should be propelled such that the suit is returned to the fixed reference point along the computed trajectory. 
     
     
         45 . The method of  claim 44 , wherein displaying the visual cue comprises displaying the visual cue to a user inside the suit. 
     
     
         46 . The method of  claim 42 , wherein providing the directional cue comprises providing an auditory cue identifying the direction in which the suit should be propelled such that the suit is returned to the fixed reference point along the computed trajectory. 
     
     
         47 . The method of  claim 42 , wherein providing the directional cue comprises providing a tactile cue identifying the direction in which the suit should be propelled such that the suit is returned to the fixed reference point along the computed trajectory.