by On Wednesday morning, a robotic lunar lander sent by a Houston company came closer to reaching the moon.
The company, Intuitive Machines, announced that its Odysseus spacecraft had fired its engines for six minutes and 48 seconds, slowing down enough to be pulled by the moon’s gravity into a circular orbit 57 miles above the surface.
On Thursday, he is scheduled to touch down on the moon. If successful, it will be the first private spacecraft to make a soft landing there and the first American mission to land there since Apollo 17 in 1972.
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When is the landing and how can I watch it?
Odysseus is expected to land on the lunar surface at 5:30 a.m. ET on Thursday. (Late Wednesday afternoon, Intuitive Machines adjusted the landing time, moving it up by 19 minutes, based on the orbit the spacecraft completed.)
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 coverage of the landing starting at 4 pm Thursday.
Where is the spaceship landing?
Odysseus aims to find a place in the southern polar region, a flat plain outside the crater Malapert A. (Malapert A is a satellite crater of the larger crater Malapert, named after Charles Malapert, a 17th-century Belgian astronomer.)
The landing site is about 185 miles from the south pole of the moon.
Some of the craters in that region remain under eternal shadow, and are of particular interest because water ice has been found in them. Previous American moon missions have landed in the equatorial regions.
How will Odysseus land?
The spacecraft will fire its engine so that the circular orbit changes to an elliptical one, and it will fall within about 6 miles of the moon’s surface. From this point on in the landing sequence, Odysseus will work completely alone. After coasting for an hour, the engine will restart, and the spacecraft will begin its powered descent. It will have to slow down from an initial speed of about 4,000 mph.
Odysseus will track its position through cameras, matching crater patterns to stored maps and measuring its height by bouncing laser beams off the surface.
About 1.2 miles from the landing site, the spacecraft will go into a direct orientation, and sensors will be looking for a safe place.
For the final 50 feet or so of descent, Odysseus will rely entirely on his inertial measurement units, which act as the spacecraft’s inner ear, measuring the forces of acceleration. It will stop using the camera and laser that measures height to avoid being distracted by dust kicked up by the engine’s exhaust.
What will the lander do on the moon?
Because solar panels provide the spacecraft’s power, its mission will only last about seven days until the sun sets on the landing site. That’s when a fortnight’s frigid moonlit night begins, and Odysseus was not meant to live in those conditions.
The six NASA instruments that carried Odysseus to the moon and what their tasks are:
— Laser reflector array that bounces back beams.
— A lidar instrument that precisely measures the height and velocity of the spacecraft as it approaches the surface of the moon.
— A stereo camera that will capture video of the dust plume produced by Odysseus’ engines during landing.
— A low-frequency radio receiver that measures the effects of charged particles on radio signals near the lunar surface, providing information that could help design future lunar radio observations.
— Warning, Lunar Node-1, which will demonstrate an autonomous navigation system.
— A tool in the propellant tank that uses radio waves to measure fuel levels.
The lander is also carrying other payloads, including a camera built by students at Embry-Riddle Aeronautical University in Daytona Beach, Florida; a precursor instrument for a 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 launched Odysseus on a trajectory towards the moon. After the spacecraft separated, it managed to turn itself on. An initial engine burn to test the propulsion system was postponed because the liquid oxygen propellant took longer to cool than predicted by ground-based tests.
Engineers adjusted the ignition procedures, and Friday’s burn was successful.
In this way, the spacecraft transmitted photographs taken of the Earth and the moon.
Flight controllers fired the engine two more times, on Sunday and Tuesday, to fine-tune the spacecraft’s path to the moon. The second attempt was precise enough that the flight controllers decided to skip a planned third correction.
How big is the spaceship?
The Intuitive Machines lander is a hexagonal cylinder with six landing legs, standing approximately 14 feet tall and 5 feet wide. For fans of “Doctor Who”, the science fiction TV show, the body of the lander is about the size of the Tardis, the time-traveling spaceship that looks like an old British police telephone booth on the outside.
At launch, with a full propellant load, the lander weighed about 4,200 pounds.
Why isn’t NASA running this mission?
Odysseus is part of NASA’s Commercial Lunar Payload Services program, which allows private companies to send experiments to the moon and allows NASA to build and operate its own lunar landers.
The space agency hopes this approach will be much cheaper, allowing it to launch more missions more often as it prepares to return US astronauts to the moon as part of its Artemis program.
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