August 16, 2022

South Korean spacecraft fueled for ride from Cape Canaveral to the moon

The Korea Lunar Pathfinder Orbiter spacecraft undergoing testing in South Korea before shipment to Florida for launch preparations. Credit: KARI

A South Korean spacecraft set for launch to the moon next week from Cape Canaveral has been loaded with the fuel it needs to maneuver into a low-altitude lunar orbit for image-taking and scientific observations.

The Korea Pathfinder Lunar Orbiter, or KPLO, spacecraft is set for launch at 7:08 p.m. EDT (2308 GMT) next Thursday, Aug. 4, aboard a SpaceX Falcon 9 rocket from Cape Canaveral Space Force Station. Mission managers said earlier this week the launch was delayed two days to allow time for SpaceX to complete additional work on the Falcon 9 rocket.

Technicians and engineers working inside SpaceX’s payload processing facility recently completed fueling of the Korean lunar probe, following the spacecraft’s delivery to Cape Canaveral from South Korea on July 6.

The spacecraft was loaded with hydrazine fuel inside the SpaceX clean room. South Korean engineers who traveled to the launch base with the KPLO spacecraft also completed final tests on the probe, South Korea’s first mission to the moon and first venture in deep space exploration.

The 1,495-pound (678-kilogram) spacecraft was expected to be encapsulated inside the Falcon 9 rocket’s payload fairing after fueling. The aeroshell will protect the spacecraft during the final phase of launch preparations, and during the first few minutes of the launch itself.

Then SpaceX will transport the payload module from the processing facility to the Falcon 9 rocket’s hangar a couple miles away, where ground teams will connect the spacecraft inside the rocket’s nose cone to the Falcon 9’s upper stage.

The entire rocket will then roll out and will be raised vertical on pad 40 at Cape Canaveral. The KPLO mission is one of two launches currently scheduled next Thursday at the Florida spaceport. A United Launch Alliance Atlas 5 rocket with a U.S. military satellite is set to lift off about 12-and-a-half hours before the Falcon 9 rocket on the KPLO mission.

Part of the KPLO mission’s purpose is in its name. The mission is a pathfinder, or precursor, for South Korea’s future ambitions in space exploration, which include a robotic landing on the moon in the early 2030s. South Korea has also signed up to join the NASA-led Artemis Accords, and could contribute to the U.S. space agency’s human lunar exploration program.

The KPLO mission is also named Danuri, a combination of the words “dal” and “nurida” in Korean, meaning “enjoy the moon.”

“The basic idea of this mission is technological development and demonstration,” said Eunhyeuk Kim from the Korea Aerospace Research Institute. “Also, using the science instruments, we are hoping to get some useful data on the lunar surface.”

The mission carries six science instruments and technology demonstration payloads.

KPLO will test a new South Korean spacecraft platform designed for deep space operations, along with new communication, control, and navigation capabilities, including the validation of an “interplanetary internet” connection using a disruption tolerant network.

The mission’s scientific objectives include mapping the lunar surface to help select future landing sites, surveying resources like water ice on the moon, and probing the radiation environment near the moon.

The $180 million (233.3 billion won) mission will launch toward the moon on a low-energy, fuel-efficient ballistic lunar transfer trajectory, a path being pioneered by NASA’s small CAPSTONE spacecraft, a tech demo mission that launched last month on a Rocket Lab mission and is scheduled to slip into orbit around the moon in November.

If KPLO launches in the first week of August, its arrival date at the moon is fixed on Dec. 16. The Falcon 9 will propel the spacecraft on a trajectory that will take it close to the L1 Lagrange point, a gravitationally-stable location nearly a million miles (1.5 million kilometers) from the daytime side of the Earth, some four times farther than the moon.

Gravitational forces will naturally pull the spacecraft back toward the Earth and the moon, where the Korean probe will be captured in orbit Dec. 16. A series of propulsive maneuvers with the spacecraft’s thrusters will steer KPLO into a circular low-altitude orbit about 60 miles (100 kilometers) from the lunar surface by New Year’s Eve.

After a month of commissioning and tests, the spacecraft’s year-long primary science mission should begin around Feb. 1. If the orbiter has enough fuel, mission managers could consider an extended mission beginning in 2024, Kim said.

One of the payloads on the KPLO, or Danuri, mission is a U.S.-built instrument named ShadowCam.

Derived from the main camera on NASA’s Lunar Reconnaissance Orbiter, ShadowCam will peer inside dark craters near the moons poles, where previous missions detected evidence of water ice deposits. The NASA-funded ShadowCam instrument is hundreds of times more sensitive than LRO’s camera, allowing it to collect high-resolution, high signal-to-noise imagery of the insides of always-dark craters using reflected light.

NASA is also providing tracking and communications support for the KPLO mission through its Deep Space Network antennas in California, Spain, and Australia. KARI, South Korea’s space agency, also has its own deep space communications antenna, but it doesn’t offer the continuous coverage of NASA’s worldwide network.

South Korea began developing the KPLO mission in 2016 for a planned launch in 2020, but officials delayed the mission after the spacecraft grew above its original launch weight, and engineers needed more time to complete detailed design work.

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Follow Stephen Clark on Twitter: @StephenClark1.

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