SpaceX released guidelines this week for companies looking to hitch a ride on its rockets.

The company published a web page and a user’s guide for those firms that want to pursue “rideshares”, which means that smaller satellites for space ride on the same rocket as a much larger satellite.

Sending stuff to space is expensive due to the cost of constructing and fueling rockets, not to mention the support operations to keep the vehicles going in orbit. But small companies can cut down on these costs by pursuing launches that already have a big satellite on board. Any excess fuel is then put towards getting the more diminutive machines into orbit.

SpaceX plans to use its venerable Falcon 9 for the program, which is a two-stage rocket that carries a variety of things into space. Some of its more famous payloads include Dragon cargo spacecraft for the International Space Station, the Transiting Exoplanet Survey Satellite (TESS) to perform exoplanet searches, and the Starlink satellites to offer broadband Internet from space.

SpaceX suggests that they can send a 440-pound satellite into one kind of orbit for as little as $1 million. The orbit is called “sun synchronous”, meaning that the satellite orbits in a path that keeps the sun at a consistent altitude — allowing for constant lighting conditions below for imagery. These missions would fly every four months, and if the customer’s satellite is delayed, they can rebook to a future mission with a 10% booking penalty.

Other orbital paths are also available, such as low Earth orbit, geostationary transfer orbit to get high above Earth, or trans-lunar injection to send satellites on to the moon. SpaceX asks that companies make inquiries about these mission possibilities to find out the costs and the timeline for launch.

The 72-page user’s guide for potential company rideshares is of a highly technical nature, but it covers various parameters that need to be considered. This includes the size of the available space for satellite, the launch conditions it would face, the environmental conditions in space, and matters relating to launch facilities and mission services.

While booking a ride isn’t quite as easy as reserving a hotel room, SpaceX does have a spot on its websites where customers can search out launch opportunities. They can also select any additional services they would like (such as insurance), and then put down a deposit to book their reservations online.