“The Greek letter delta is a standard notation in mathematics for a change in value. Delta-v describes a change in velocity. All celestial objects are in motion—which means you either need to accelerate or decelerate to reach them. The higher the delta-v, the greater the energy—and the greater the expense. When it comes to commerce in space, J.T., delta-v means the difference between profitability and loss. In other words: delta-v means everything.”
