Intuitive Machines' first lunar lander There was an official power outage today. After spending 7 days on the moon. The lander was the first American hardware to reach the moon's surface since 1972 and made history as the first privately built spacecraft to land on the moon. But this lander, called Odysseus, will be remembered for another reason: its propulsion system.
Its propulsion system, which uses a combination of cryogenic liquid oxygen and liquid methane, could unlock new capabilities in space and reduce risk for future missions by other commercial providers.
Prior to Intuitive Machines' IM-1 mission, no lander existed using this combination of propellants. If this sounds familiar, it's because it's used in high-performance rocket engines such as SpaceX's Raptor, Blue Origin's BE-4, and Relative Space's Ion R.
However, landers, and most spacecraft today, use “space storable” or highly concentrated propellants such as hydrazine and nitrogen tetroxide, which can be passively stored but are highly toxic. In contrast, “cryogens” are more efficient, more energetic, and much less dangerous, but require active cooling to very, very low temperatures.
This poses some unique challenges. Because the fuel must be kept very cold, it can only be stored for a very short time before launch. To get around this problem, Intuitive Machines and SpaceX designed the Nova-C class lander's VR900 engine to run just three hours before liftoff, when the rocket was on the launch pad and the spacecraft was already inside the rocket. (manufactured by IM). payload fairing. This is not typical.
The situation is so unusual that SpaceX had to develop an entirely new capability to fuel the lander, said Bill Gerstenmayer, SpaceX's vice president of construction and flight reliability. This was stated at a press conference on May 13th. This included modifications to the launch pad. Adds an adapter to access the second stage of the Falcon 9 rocket and the payload fairing if it is already installed on the vehicle.
The two companies held two wet dress rehearsals before the release. Due to problems with propellant loading, the first launch was postponed by one day to February 15th. After the successful launch, Intuitive Machines also encountered a brief problem cooling the liquid oxygen supply line, which took longer than expected. Once the propellant had cooled enough, flight controllers successfully ignited the engine the next day for the first time in space.
The company used highly efficient liquid oxygen and liquid methane, which allowed it to take a more direct trajectory to the moon. The spacecraft only had to pass through the Van Allen belt, a high radiation belt around Earth, once, reducing the spacecraft's exposure to harmful high-energy particles.
The two VR900 engines will also be used in Intuitive Machines' larger “Nova-D” spacecraft, which will deliver payloads of 500 to 750 kilograms to the moon. (The Nova-C lander has a payload capacity of 100 kilograms.)
The Nova-C and Nova-D landers will not be the last spacecraft to use cryogenic propellants in space. Impulse Space's high-energy kick stage, Helios, uses cryogen to deliver payloads directly to geostationary orbit, CEO Tom Mueller explained in a January interview.
“People used to talk about doing big kick stages in hypergoals, but I just thought, you're talking a lot of propellant and the price and safety costs are prohibitive. “It’s a thing,” he said. “So it makes sense in some ways to use very low-cost, very high-energy propellants like liquid oxygen or liquid methane.”
One of the six NASA scientific research payloads that Odysseus carried to the surface also directly utilized cryogenic propulsion systems. A statement from the agency's Glenn Research Center's Radio Frequency Mass Meter uses radio waves and antennas to measure how much propellant is in an engine's tank. This is a technology that could be essential for measuring spacecraft fuel levels during long space missions, especially since measuring liquids in microgravity can be difficult due to “slosh”. is.
This issue is of particular importance to NASA. That's because NASA's Artemis mission to return humans to the moon relies on spacecraft that use cryogenic propellants, primarily SpaceX's Starship Human Landing System and Blue Origins' Blue Moon. These missions require the transfer of large amounts of cryogenic fluid from an orbital reservoir to a spacecraft. Although these fluids will need to be in orbit for much longer than Odysseus did when he traveled to the moon, the IM-1 mission still kicks the door squarely open for cryogenic applications in space.