Hot Air Balloon Lifting Gas
Hot Air Balloon Lifting Gas calculates the volume, mass, weight, and buoyant force for a sphere of air on Earth at sea level temperature and pressure for selected radii and selected temperatures equal to or greater than ambient temperature, to be used by students in the Mars City Balloon Physics Challenge.

Earth Balloon Envelope
Earth Balloon Envelope calculates the volume of a balloon and the mass and weight of the balloon envelope for selected balloon radii, envelope materials, and envelope material thicknesses, to be used by students in the Mars City Balloon Physics Challenge.

Earth Balloon Lifting Gas
Earth Balloon Lifting Gas calculates the radius, volume, and weight of a sphere of a selected mass of air, hydrogen, helium, carbon dioxide, or methane on Earth at sea level temperature and pressure, to be used by students in the Mars City Balloon Physics Challenge.

Mars Balloon Envelope
For a balloon envelope constructed of layers of Mylar, Kevlar scrim, and low-density polyethylene, Mars Balloon Envelope calculates the volume of the balloon, and the mass and weight of the balloon envelope for selected balloon radii and envelope material thicknesses, to be used by students in the Mars City Balloon Physics Challenge.

Mars Balloon Lifting Gas
Mars Balloon Lifting Gas calculates the volume, mass, and weight of a sphere of hydrogen, helium, or Martian atmospheric gas of a selected radius at conditions of temperature and pressure associated with the mean Martian surface elevation, to be used by students in the Mars City Balloon Physics Challenge.