Economies of Scale in Space Launches

A launch has some costs that do not change much with the payload mass carried on that mission. When these fixed costs are divided among more payload kilograms, the average cost per kilogram falls, creating economies of scale.

Cost relationship

For payload mass M, fixed cost F and mass-dependent variable cost V(M), cost per kilogram = F/M + V(M)/M. As M rises within the same launch configuration, F/M declines because the mission's fixed cost is spread across more kilograms.

• If variable cost rises less than proportionately with payload mass, the total average cost per kilogram also falls.
• The relevant denominator is the payload actually carried to the required orbit, not merely the launch vehicle's advertised maximum capacity.

How scale is achieved

Scale can be obtained by carrying a larger primary payload or combining several compatible payloads through rideshare or shared launches. At the programme level, a higher launch cadence can also spread standing expenditure on facilities, specialised personnel and support systems across more missions.

• Better utilisation reduces the unused capacity for which the launch operator must still incur mission costs.
• Payload aggregation allows several customers to share costs that would otherwise be borne by one customer.

Limits to the cost advantage

The relationship is not unlimited because each vehicle has mass, volume and orbital-performance constraints. Moving to a larger vehicle may raise total fixed and variable costs, so per-kilogram cost falls only when the additional payload sufficiently improves capacity utilisation.

• Payloads must be compatible in destination, schedule, integration requirements and mission risk.
• Cost per kilogram does not by itself measure reliability, precision of orbital insertion, responsiveness or suitability for small dedicated missions.