Chinese rover discovers 'gel-like' substance on Moon

Even as Isro’s Pragyan lunar rover is set to enter the lunar landscape next weekend, China’s Yutu-2 lunar explorer, which has been crawling along the far side of the moon since January 2019, has stumbled upon something unexpected, scientists said.

The discovery is an unusually-colored “gel-like” substance which was found by the rover near its landing site in the Von Kármán crater on July 25, during day 8 of the lunar day cycle. The discovery was revealed in Chinese National Space Administration’s (CNSA) Our Space magazine on August 17, which includes a section called the Yutu-2 “Drive Diary.”

In the diary, scientists controlling the Yutu-2 (Chinese for “Jade Rabbit”) said they were preparing to routinely deactivate the solar-powered rover during mid-day, to prevent the rover from being fried by high temperature radiation from the sun which reaches its apex at that time, when a team checking images from the rover’s main camera spotted a small crater containing a material with a color and lustre unlike the lunar terrain.

Postponing the power-down, the team sent the rover to continue west to inspect the material. Unlike India’s Pragyan 2, which has a battery of eight instruments, ranging from a terrain mapping camera to x-ray and infrared spectrometers to gear intended to study the moon’s atmosphere, the Yutu-2 has three instruments, including an alpha-particle x-ray spectrometer (APXS) and visible/infrared spectrometer (VNIS), ground penetrating radar, plus four cameras.

The VNIS detects light that is scattered or reflected off surfaces to reveal their makeup. While the Chinese science team has not disclosed the results of the VNIS test on the material, Space.com said on Saturday that outside researchers believed that the “substance is melt glass created from meteorites striking the surface of the moon.”

Unlike other space agencies, the CNSA is notoriously tight-lipped about missions, and the discovery was not disclosed to the international community.

Isro chairman K Sivan has said that he has high hopes that Chandrayaan-2 will also make breathtaking discoveries. One of the primary aims of the Chandrayaan-2 mission is to collect data on ice in the south pole. The presence of ancient ice was found by Nasa’s M3 “Moon Mineralogy Mapper” which was deployed aboard Chandrayaan 1, over a decade ago, in 2008.

Scientists have said that they believe the ice, which is never rises about -156.6°C is ancient because it lies in the shadow of lunar craters where it possibly never melts.

Chandrayaan-2 will build on this discovery by using its Dual Frequency Synthetic Aperture Radar (DFSAR), to carry out a quantitative estimation of water-ice below the surface in the south pole.

The discovery of the gel-substance is not the first surprise discovery on the moon. In 1972, US astronaut Harrison Schmitt of Apollo 17 reported orange-colored soil near the mission’s Taurus-Littrow landing site, which lunar geologists later concluded was created by a massive volcanic explosion 3.64 billion years ago.

The moon’s synchronous rotation causes its far side to be closer to the sun during the local day than the moon’s near side which faces the earth. A typical lunar day lasts 29 earth days, 12 hours and 44 minutes. This is the time it takes for the Moon to orbit around the Earth.

The landing of Chandrayaan-2's “Vikram” lander on the lunar south pole on September 7, will occur during day 9 of the new lunar day cycle, which began last weekend.