Flexible propulsion system

A method of fabricating a propulsion system for use on a spacecraft, the method comprising:

• assembling a plurality of subassemblies of the propulsion system, including a first quantity ‘n’ of identically sized pressurant tanks, at least one chemical thruster operable with a liquid propellant and at least one electric thruster operable with a high atomic weight inert gas;
• making a first determination of a first selectable number ‘e’ of the first quantity of identically sized pressurant tanks to be manifolded together with the at least one electric thruster and loaded with the high atomic weight inert gas such that the at least one electric thruster is provided with the high atomic weight inert gas;
• making a second determination of a second selectable number ‘c’ of the first quantity of identically sized pressurant tanks to be manifolded together with the at least one chemical thruster and loaded with helium or other low atomic weight pressurant;
• and
• fabricating the propulsion system from the plurality of subassemblies in accordance with the first determination and the second determination;
• wherein
• ‘e’ is an integer;
• c=n−e;
• and
• ‘e’ is less than ‘n’ and greater than zero.

A spacecraft comprising:

• a propulsion system including:
• at least one chemical thruster operable with a liquid propellant;
• at least one electric thruster operable with a high atomic weight inert gas;
• and
• a first quantity ‘n’ of identically sized pressurant tanks;
• wherein:
• the propulsion system results from assembling a plurality of subassemblies, such that a first selectable number ‘e’ of the first quantity of identically sized pressurant tanks are manifolded together with the at least one electric thruster and loaded with the high atomic weight inert gas such that the at least one electric thruster is provided with the high atomic weight inert gas, and a second selectable number ‘c’ of the first quantity of identically sized pressurant tanks are manifolded together with the at least one chemical thruster and loaded with helium or other low atomic weight pressurant;
• ‘e’ is an integer c=n−e;
• and
• ‘e’ is less than ‘n’ and greater than zero.