Intuitive Machines’ first lunar lander formally misplaced energy in the present day after spending seven days on the moon. The lander made historical past for being the primary American {hardware} to achieve the lunar floor since 1972 and the primary privately constructed spacecraft to land on the moon. However the lander, known as Odysseus, will likely be remembered for one more cause: its propulsion system.
That propulsion system, which makes use of a mixture of cryogenic liquid oxygen and liquid methane, might unlock new capabilities in area and de-risk future missions by different industrial suppliers.
Earlier than Intuitive Machines’ IM-1 mission, no lander had ever used this mixture of propellants. In the event that they sound acquainted, it’s as a result of they’re utilized in high-performance rocket engines, like SpaceX’s Raptor, Blue Origin’s BE-4 and Relativity Area’s Aeon R.
However landers — and most spacecraft in the present day — use “area storable” or hypergolic propellants, like hydrazine or nitrogen tetroxide, which could be passively saved however are extremely poisonous. In distinction, “cryogens” are extra environment friendly, increased power and significantly much less harmful, however they have to be actively cooled to very, very low temperatures.
This presents some distinctive challenges. As a result of the fuels have to be saved so chilly, they’ll solely be saved previous to lift-off for a really quick period of time. To get round this situation, Intuitive Machines and SpaceX began fueling the Nova-C class lander’s VR900 engine (which was constructed by IM) simply three hours earlier than lift-off, when the rocket was on the launch pad and the spacecraft was already contained in the payload fairing. That is something however typical.
It’s so out-of-the-ordinary that SpaceX needed to develop solely new capabilities to gasoline the lander, Invoice Gerstenmaier, SpaceX’s VP of construct and flight reliability, stated throughout a press convention on February 13. That included modifying the launch pad and the second stage of the Falcon 9 rocket and including an adapter to entry the payload fairing when it was already mated to the car.
The 2 firms carried out two moist costume rehearsals previous to launch; points with propellant loading resulted within the first launch try being pushed by a day, to February 15. After the profitable launch, Intuitive Machines additionally bumped into a short situation chilling the liquid oxygen feed line, which took longer than anticipated. As soon as the propellant was sufficiently cooled, flight controllers efficiently fired the engine in area for the primary time the next day.
As a result of the corporate was utilizing liquid oxygen and liquid methane, that are extremely environment friendly, they had been in a position to take a extra direct trajectory to the moon. The spacecraft solely needed to transit the Van Allen belt, a high-radiation zone across the Earth, as soon as, which lowered the spacecraft’s publicity to damaging high-energy particles.
Two VR900 engines will even be used on Intuitive Machines’ a lot bigger “Nova-D” spacecraft, to ship 500-750 kilograms of payload to the moon. (The Nova-C lander has a payload capability of 100 kilograms.)
The Nova-C and Nova-D landers will likely be removed from the final spacecraft to make use of cryogenic propellants in area. Impulse Area’s high-energy kick stage, Helios, will use cryogens to ship payloads on to geostationary orbit, CEO Tom Mueller defined in an interview from January.
“Folks have talked about doing huge kick phases with hypergols earlier than, and I simply suppose, you’re speaking tons of propellant and the worth and the price of security are simply exorbitant,” he stated. “So utilizing very low-cost, very high-energy propellants like liquid oxygen and liquid methane is form of like a no brainer.”
One of many six NASA science and analysis payloads that Odysseus carried to the floor additionally immediately leveraged the cryogenic propulsion system. The Radio Frequency Mass Gauge assertion from the company’s Glenn Analysis Heart makes use of radio wave and antenna to measure how a lot propellant is offered within the engine’s tanks. It’s know-how that might be important for measuring spacecraft gasoline ranges throughout long-duration area missions, particularly as a result of “slosh” could make measuring liquids in microgravity a problem.
This situation is of particular significance to NASA as a result of the company’s Artemis missions to return people to the lunar floor rely on spacecraft that use cryogenic propellants — mainly SpaceX’s Starship Human Touchdown System and Blue Origins’ Blue Moon. These missions would require transferring giant quantities of cryogenic fluids from on-orbit depots to the spacecraft; whereas these fluids will must be on orbit for much longer than Odysseus was in transit to the moon, the IM-1 mission continues to be squarely kicking down the door for cryogenic use in area.