- By Jonathan Amos
- Science reporter
Japan's moon lander ended up on its nose when it made its historic touchdown on the lunar surface.
The first image of the stricken Slim spacecraft shows it rotated 90 degrees from how it should have come to rest.
This is one way to explain the difficulties in generating the electricity needed to run it.
The film was captured by a tiny baseball-sized robot called Sora-Q, which was ejected from Slim moments before last Saturday's touchdown.
“An abnormality in the main engine affected the spacecraft's landing approach,” Japanese space agency JAXA said in a statement.
One of the two large thrusters on the Slime (the Smart Lander for Investigating the Moon) stopped working during landing.
To get the image to Earth, Sora-Q first had to send it to a second ejected roving robot, Lunar Rover 1, or Lev-1. The hopping robot has radio equipment that can communicate with mission control independently of the slime.
Three hours after landing, the lander was shut down because its solar cells were no longer functional. As the battery was draining fast, JAXA officers decided to put Slim to sleep.
Their assumption — which appears to be confirmed by the Sora-Q image — is that the main spacecraft is oriented to block the solar cells from looking at the Sun.
The trick is to wake up the slime when the lighting angles change in its landing spot.
Before hibernation, the controllers were able to pull down a series of images of the surface taken by its in-infrared camera.
These show the spacecraft on a slope surrounded by small rocks.
Slime's landing site is at the edge of an equatorial trough called Sheoli.
Landing at 00:20 Japan Standard Time (15:20 GMT) on Saturday, JAXA became the fifth national space agency to have a soft touch on the moon – after the United States, the former Soviet Union, China and India.
Statistically, soft landing on the lunar surface has proven very difficult. Only half of all attempts are successful.
Jaxa believes in new precision navigation technologies.
The lander's onboard computer used rapid image processing and crater mapping to avoid hazards to reach its touchdown point.
Engineers wanted to get within 100m (330 ft) of their target. It was achieved.
“Analysis of data obtained before power-down confirmed that the slime had reached the lunar surface about 55 m east of the original target landing site,” Jaksa said, adding that the onboard computer also made a decision in the final moments of landing. Move the craft sideways to avoid obstacles.
This will please the officials as much as the success of the two rovers. Not only did Sora-Q hover over the lunar surface and take a picture of it, it also managed to make a Lev-1 jump. Like Slim, Lev-1 is not working.
“The flight maneuvers of Lev-1 on the lunar surface, the communication between the robots between Lev-1 and Sora-Q, and the fully autonomous operations represent a ground-breaking achievement. It is considered a valuable technical demonstration for future lunar explorations. , and the knowledge and experience gained will be used in future missions” The company said.
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