Liquid methane and oxygen are the Current Thing in rocket propellants these days. Methane as fuel, while cryogenic, boils at 111.6 °K and does not require the extreme refrigeration of liquid hydrogen (20.28 °K). It is much more dense, reducing the size and mass of fuel tanks, does not embrittle metals or leak as easily, and since it is a main component of natural gas, is far less expensive. Methane fuel can be manufactured on Mars from atmospheric carbon dioxide and subsurface ice.
Liquid methane fuel has been chosen by the SpaceX Starship, ULA Vulcan Centaur, Blue Origin New Glenn, Relativity Space Terran 1, and LandSpace Zhuque-2 launchers. Rocket watchers have been wondering which will be the first to reach orbit with a methane-fuelled first stage.
On 2023-07-11, China’s LandSpace Zhuque-2 won the race, placing its upper stage in a 431 by 461-kilometer Sun-synchronous orbit with an inclination of 97.3 degrees.
Landspace’s Zhuque-2 is powered by gas generator engines producing 268 tons of thrust. Future Zhuque-2 launches with upgraded second stage engines will be capable of delivering a 6,000-kilogram payload capacity to a 200-kilometer low Earth orbit (LEO), or 4,000 kilograms to 500-kilometer sun-synchronous orbit (SSO), according to Landspace.
The rocket has a diameter of 3.35 meters—the same as a number of national Long March rockets—and a take-off mass of 219 tons.