The first lunar lander from Intuitive Machines Officially lost power today After spending seven days on the moon. The lander made history as the first American device to reach the lunar surface since 1972 and the first privately built spacecraft to land on the lunar surface. But the lander, called Odysseus, will be remembered for another reason: its propulsion system.
This propulsion system, which uses a combination of cryogenic liquid oxygen and liquid methane, could open up new capabilities in space and de-risk future missions undertaken by other commercial providers.
Prior to Intuitive Machines' IM-1 mission, no lander had ever used this propellant mixture. If they look familiar, it's because they're used in high-performance rocket engines, like SpaceX's Raptor, Blue Origin's BE-4, and Relativity Space's Aeon R.
But landers — and most spacecraft today — use “space storable” or highly active fuels, such as hydrazine or nitrogen tetroxide, which can be stored passively but are highly toxic. In contrast, “chillers” are more efficient, higher energy and considerably less dangerous, but must be effectively cooled to very, very low temperatures.
This presents some unique challenges. Because the fuel must be kept very cold, it can only be stored for a very short time before takeoff. To overcome this problem, Intuitive Machines and SpaceX started fueling the Nova-C lander's VR900 engine (built by IM) just three hours before liftoff, when the rocket was on the launch pad and the spacecraft was already inside the spacecraft. Load gift. This is just typical.
“It is so unusual that SpaceX has had to develop completely new capabilities to fuel the lander,” Bill Gerstenmaier, SpaceX's vice president of construction and flight reliability, said during a Feb. 13 press conference. This included modifying the launch pad and second stage of the Falcon 9 rocket and adding an adapter to access the payload interface when it is already attached to the vehicle.
Both companies performed two wet training exercises before the launch. Propellant loading problems led to the first launch attempt being postponed by one day, until February 15. Following the successful launch, Intuitive Machines also had a brief issue with the cooling of the liquid oxygen feed line, which took longer than expected. Once the propellant had cooled sufficiently, flight controllers successfully launched the engine into space for the first time the next day.
Because the company was using liquid oxygen and liquid methane, which are highly efficient, they were able to take a more direct path to the moon. The spacecraft had to cross the Van Allen Belt, a high-radiation zone around Earth, only once, which minimized the spacecraft's exposure to harmful, high-energy particles.
Two VR900 engines will also be used in Intuitive Machines' larger Nova-D spacecraft, delivering 500 to 750 kilograms of payload to the Moon. (The Nova-C lander has a payload capacity of 100 kilograms.)
The Nova-C and Nova-D landers will be far from the last spacecraft to use cryogenic propellant in space. Impulse Space's high-energy kick stage, Helios, will use cryogens to deliver payloads directly to geostationary orbit, Impulse Space CEO Tom Mueller explained in a January interview.
“People have talked about doing big stages with hyperjules before, and I think you're talking about a lot of propellant and the price and safety cost are very high,” he said. “So using very low-cost, very high-energy propellants, like liquid oxygen and liquid methane, is kind of a no-brainer.”
One of NASA's six science and research payloads that Odysseus carried to the surface also directly benefited from the cryogenic propulsion system. The agency's Glenn Research Center radio-frequency mass meter statement uses a radio wave and antenna to measure the amount of propellant available in an engine's tanks. It's a technique that could be vital for measuring spacecraft fuel levels during long-duration space missions, especially since “flow” can make measuring liquids in microgravity a challenge.
The issue is of particular importance to NASA because the agency's Artemis missions to return humans to the lunar surface rely on spacecraft that use cryogenic propellants — primarily SpaceX's Spacecraft Human Landing System and Blue Origins' Blue Moon. These missions will require transferring large quantities of cryogenic liquids from on-orbit warehouses to the spacecraft; While these liquids would need to remain in orbit much longer than Odysseus spent transiting to the Moon, the IM-1 mission still directly opens the door to cryogenic use in space.
