Columbia subject headings:
Mars (Planet)--Exploratin--Automation.
Mars (Planet)--Exploration--Automation.
Mars (Planet)--Research--United States.
Moon--Exploration--Automation.
Moon--Research--United States.
Robotics.
Harvard subject headings:
Mars (Planet)--Exploration--Automation.
Mars (Planet)--Exploration--Government policy--United States.
Mars (Planet)--Research--United States.
Moon--Exploration--Automation.
Moon--Exploration--Government policy--United States.
Moon--Research--United States.
Robotics.
Princeton subject headings:
Mars (Planet)--Exploration--Automation.
Mars (Planet)--Research--United States.
Moon--Exploration--Automation.
Moon--Research--United States.
Robotics.