WASHINGTON — Virgin Orbit, while preparing for the first flight of its LauncherOne smallsat rocket, is in the process of choosing an engine for a three-stage variant that would be capable of sending payloads to other planets.

John Fuller, Virgin Orbit advanced concepts director, said the company is deciding between three “highly energetic third stage” options for LauncherOne that would enable the rocket to launch up to 50 kilograms to Mars or 70 kilograms to Venus. The “Exploration 3-Stage Variant” of LauncherOne would also have the ability to launch around 100 kilograms to the moon or toward Lagrange points, he said.

“What we do is we take that third stage and bring the overall impulse of the vehicle up to a point where we can reach very high energies to launch to cis-lunar, interplanetary or even asteroid targets,” Fuller said Oct. 24 at the 70th International Astronautical Congress here.

LauncherOne is a two-stage liquid-propellent rocket Virgin Orbit plans to launch from the wing of a modified Boeing 747 aircraft. The rocket is designed to launch 300 to 500 kilograms to low Earth orbit, with the exact amount determined by orbital inclination.

Virgin Orbit still anticipates completing the maiden flight of its normal two-stage LauncherOne rocket this year, Fuller said. A “very large contingent” of Virgin Orbit staff are in Mojave, California, right now preparing the first rocket, he said. They will attach the rocket to Cosmic Girl, Virgin Orbit’s structurally enhanced Boeing 747, and will run it through a series of “wet dress rehearsals” where the rocket is fueled up but not launched, before conducting the actual mission, he said.

Fuller estimated Virgin Orbit will choose a third stage for LauncherOne in “the next month or two.” Pacing that decision is a Mars mission Virgin Orbit plans to launch for Polish satellite manufacturer SatRevolution in the third quarter of 2022, he said.

Virgin Orbit announced forming a consortium with SatRevolution and close to a dozen Polish universities Oct. 9 aimed at conducting the first commercial smallsat mission to Mars.

Fuller said Virgin Orbit would reveal pricing for interplanetary missions soon.