Apparatus, method and system for balloon altitude control by in-situ characterization and active energy management

An apparatus comprising:

• a balloon;
• an expandable envelope carried by the balloon and containing a lift gas that responds to addition and removal of energy by expanding and contracting the envelope;
• and
• an altitude control system carried by the balloon and configured to control the balloon's altitude, the altitude control system including (a) a lift gas characterizer that measures in-situ characteristics of the lift gas in the envelope, (b) a processor that measures in-situ characteristics of a surrounding environment outside the envelope, and (c) an active energy management system that adds energy to the lift gas and removes energy from the lift gas based on the in-situ characteristics of the lift gas in the envelope.

A method comprising:

• controlling an altitude of a balloon having an expandable envelope containing a lift gas that causes the balloon to change altitude by:
• (a) measuring in-situ characteristics of the lift gas in the envelope;
• (b) measuring in-situ characteristics of a surrounding environment outside the envelope;
• (c) comparing the in-situ characteristics of the lift gas in the envelope against pre-programmed lift gas state data;
• (d) identifying an energy requirement for the lift gas based on (c) needed for the balloon to achieve a desired altitude;
• and
• (e) activating an active energy management process which (i) adds energy to the lift gas to cause the balloon to ascend, (ii) removes energy from the lift gas to cause the balloon to descend, (iii) removes lift gas from the envelope, and (iv) adds ambient fluid to the lift gas.