On Wednesday morning, a robotic lunar lander launched by a Houston company moved closer to reaching the moon.
Intuitive Machines announced that its Odysseus spacecraft ran its engine for six minutes and 48 seconds, slowing it enough to be pulled by the moon's gravity into a circular orbit 57 miles above the surface.
It is scheduled to land on the moon on Thursday. If all goes well, it will become the first private spacecraft ever to make a soft landing there and the first American mission to get there since Apollo 17 in 1972.
When is the landing and how can I watch it?
Odysseus is expected to land on the moon's surface at 5:30 PM ET on Thursday. (Late Wednesday afternoon, Intuitive Machines adjusted the landing time, raising it by 19 minutes, based on the orbit the spacecraft reached.)
Although it is a private mission, the main customer is NASA, which paid $118 million to deliver six instruments to the moon. NASA TV will broadcast the coverage From landing starting at 4 pm on Thursday.
Where will the spacecraft land?
Odysseus aims for a place in the Antarctic region, a flat plain outside the Malaparte A crater. (Malaparte A is a satellite crater of the larger Malaparte Crater, named after Charles Malaparte, a 17th-century Belgian astronomer.)
The landing site is about 185 miles from the moon's south pole.
Some of those craters in that area are still in permanent shade, and it is an area of special interest because water ice was discovered there. Previous US moon missions have landed in the tropics.
How will Odysseus land?
The spacecraft will turn its engine so that the circular orbit changes to an elliptical orbit, and it will descend to within about six miles of the moon's surface. From this point on in the landing sequence, Odysseus will operate entirely on his own. After landing for an hour, the engine will start up again, and the spacecraft will begin its powered descent. It will have to slow down to its initial speed of about 4,000 miles per hour.
Odysseus will track its location through cameras, match crater patterns to stored maps and measure its height by bouncing lasers off the surface.
About 1.2 miles from the landing site, the spacecraft will rotate in a straight line, with sensors searching for a safe spot.
For the last approximately 50 feet of descent, Odysseus will rely solely on the inertial measurement units, which serve as the spacecraft's inner ear, measuring acceleration forces. It will stop using the camera and laser that measure altitude to avoid being fooled by dust from engine exhaust.
What will the probe do on the moon?
Because solar panels provide power to the spacecraft, its mission will last only about seven days until the sun sets at the landing site. That's when a frigid two-week lunar night begins, and Odysseus was not designed to survive those conditions.
The six NASA tools that Odysseus carried to the moon and what their tasks were:
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An array of laser reflectors that bounce laser beams.
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The LIDAR instrument precisely measures the spacecraft's altitude and speed as it descends to the lunar surface.
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A stereo camera will capture video of the dust plume produced by Odysseus' engines during landing.
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A low-frequency radio receiver measures the effects of charged particles on radio signals near the moon's surface, providing information that can help design future radio observations on the moon.
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A beacon, Lunar Node-1, will demonstrate an autonomous navigation system.
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An instrument located in the fuel tank that uses radio waves to measure fuel levels.
The lander also carries other payloads, including a camera built by students at Embry-Riddle Aeronautical University in Daytona Beach, Florida; A primer for the future lunar telescope; And an art project by Jeff Koons.
How is the mission going so far?
Mostly very well.
On February 15, a SpaceX Falcon 9 rocket sent Odysseus on a trajectory toward the Moon. After the spacecraft separated, it successfully powered itself. The initial engine burn was postponed to test the propulsion system because the liquid oxygen propellant took longer to cool than ground tests had anticipated.
Engineers modified the ignition procedures, and the burn was successfully conducted on February 16.
Along the way, the spacecraft sent back captured images of both Earth and the Moon.
Flight controllers turned the engine on two more times, on February 18 and 20, to set the spacecraft's path to the Moon. The second effort was accurate enough that flight controllers decided to skip the planned third correction.
What is the size of the spacecraft?
The Intuitive Machines lander is a hexagonal cylinder with six landing legs, about 14 feet high and five feet wide. For fans of “Dr. Who,” the sci-fi TV show, the lander is roughly the size of the Tardis, a time-traveling spacecraft that from the outside looks like an old British police phone booth.
At launch, with a full payload of propellant, the lander weighed about 4,200 pounds.
Why doesn't NASA do this mission?
Odysseus is part of NASA's Commercial Lunar Payload Services program, which allows private companies to send experiments to the Moon and spares NASA from building and operating its own lunar landers.
The space agency hopes this approach will be much cheaper, allowing it to send missions more frequently as it prepares for the return of American astronauts to the moon as part of its Artemis program.
