Not every mission needs its own satellite. A hosted payload is an instrument or piece of equipment that flies on a spacecraft or platform operated by someone else, which provides power, data and a ride to orbit. For start-ups, research groups and agencies, hosting can be the fastest way to get hardware into space.
Where payloads can be hosted
- Commercial satellites: an extra instrument is added to a satellite built for another purpose, for example a communications satellite in geostationary orbit.
- Hosting platforms and orbital transfer vehicles: spacecraft designed to carry several customer payloads for a defined mission.
- The International Space Station: external platforms on the station allow experiments to be exposed directly to space, as shown on the cover image.
- Rideshare upper stages: some missions use the upper stage itself as a short duration platform.
Advantages
- No need to develop a complete satellite bus.
- Lower cost and often shorter lead times.
- Access to orbits and missions that a small project could not afford alone.
Limitations
- The schedule, orbit and lifetime follow the host mission.
- Mass, volume, power and data rates are limited and must be negotiated.
- The payload must not interfere with the host's own operations, which leads to strict interface and testing requirements.
When hosting makes sense
Hosting is well suited to technology demonstrations, sensors that need flight heritage and services that benefit from sharing infrastructure. For operational services that need full control over orbit and availability, a dedicated satellite is usually the better choice.
Related reading
- CubeSats Explained: Sizes, Standards and How They Reach Orbit
- Space Tugs Explained: How Orbital Transfer Vehicles Deliver Satellites
- Rideshare or Dedicated Launch? How Small Satellites Get to Orbit
Sources
- NASA Small Spacecraft Systems Virtual Institute: State of the Art of Small Spacecraft Technology
- NASA: International Space Station
Cover image: An external payload platform installed on the Japanese Experiment Module Exposed Facility of the International Space Station. Credit: NASA (iss048e050816), public domain.