Worries are growing about a shortage of medium-lift rockets in the U.S. space launch market. As SpaceX cuts back on new commercial contracts for its main Falcon 9 launch vehicle, competition is intensifying among space companies seeking to fill the gap.

Ars Technica, an IT media outlet, reported on Oct. 20 local time that SpaceX is expected to phase down Falcon 9 commercial launch services as early as 2028.

The problem is that there are not enough replacement launch vehicles. Vulcan and New Glenn have growing backlogs, and costs are high for small and medium satellite launches. New rockets have not yet completed even their first flights, increasing uncertainty for satellite operators trying to secure launch schedules.

In the United States, companies including Stoke Space, Relativity Space, Rocket Lab and Firefly Aerospace are developing next-generation launch vehicles.

The fastest candidate is Stoke's Nova. It is designed to carry 3 tons to low Earth orbit in a fully reusable configuration and 7 tons in an expendable configuration. Production of the first stage is entering its final phase, and the company is targeting an initial launch in early 2027.

Relativity Space's Terran R is a heavy rocket that can carry up to 33.5 tons in an expendable configuration. It recently completed tests of 13 first-stage engines and an integrated hot-fire test of the second stage.

Rocket Lab's Neutron is being developed to launch 8.5 to 15 tons depending on reusability conditions. Its first launch has been delayed to 2027 due to issues making the engine and carbon-composite fuel tanks.

Eclipse, jointly developed by Northrop Grumman and Firefly, is developing the Miranda engine, but the overall status of building the launch vehicle is relatively unclear.

The outlet expected first launches in July 2027 for Nova, September that year for Terran R, January 2028 for Neutron, and after 2029 for Eclipse.

Even if the new rockets succeed in launching on schedule, how quickly they can ramp up the number of launches is expected to be a key task for the U.S. space industry.