China’s Sophisticated Space Missions: Collecting Lunar Sample Back to Earth, Satellites to Trace Gravitational Waves

Chang’e 5, the moon mission of China launched in November 23rd has been in news for almost a month now. The mission to collect rock and dust samples from the surface of the moon was the first in last 40 years. And it has been successful so far. As per reports, the space capsule is enroute back to Earth with 2 Kg s of rock samples collected from the site on moon known as Mons Rumker. On December 13th, the space capsule has started its three days journey.

The Chang’e 5 mission has attained the sophistication and has become a landmark when it robotically drilled into the lunar surface and collected the sample hereafter. Such robotic operation in lunar missions were not visible in previous instances. The last lunar sample collecting mission to be proven successful was that of Soviet Russia’s Luna 24 back in 1976.

China has built up labs to analyse the lunar samples. These are thought to be billions of years younger than the samples collected previously and are expected to shed new lights on the evolution of the solar system.

Amidst Chang’e 5 there is another Chinese space mission that has gained attention. China’s National Space Science Center (NSSC) of the Chinese Academy of Sciences (CAS) has launched another technically sophisticated endeavor into the space, the GECAM (Gravitational Wave High-energy Electromagnetic Counterpart All-Sky Monitor) from the Xichang Satellite Launch Center situated in the Sichuan province. The launch was made on 10th December. The GECAM system is launched aiming to trace the origin of gravitational waves in the space. For doing so, the system is programmed to detect gamma ray bursts which emanate from merging of highly dense objects like merging of neutron stars, the dead core leftover of a supernova explosion. These celestial activities also generate gravitational waves.

The GECAM system has two satellites, each of 130 centimeters height and weighing 150 kilograms. These two satellites are now orbiting earth at a height of 600 kilometers, and are situated at opposite sides of earth.

Back in 2017, scientists could see celestial lights generated from the event where a pair of neutron stars merged. Again, merging of a black hole and a neutron star is also thought to generate such lights and the gravitational waves. But whether two black holes merger could create such lights still remains an unanswered question.

The two satellites embedded in the GECAM system can now monitor the whole sky which will capacitate them to trace the source of a gamma ray burst. Before the Chinese mission was put into the space other such gamma ray observatories in place are the Neil Gehrels Swift Observatory and the Fermi gamma ray space telescope of NASA. But, both of these are limited in their capacities to have partial views of the sky and sometimes are blocked by Earth. Also, “Swift and Fermi are optimized to capture the longer, higher energy gamma ray bursts that hail from the collapse of massive stars. GECAM’s observational energy range extends down to 6 kiloelectronvolts, lower than Swift and Fermi, which may be an advantage spotting the softer gamma ray bursts associated with gravitational waves”—says Xiong Shaolin, the astrophysicist and the principal investigator of the GECAM system.

Moreover, the NASA facilities have also aged. Swift was launched in the year 2004 and for a period of 2 years while Swift is in the orbit since 2008 and it was expected to provide service for five to ten years. In this case China’s GECAM system is considered something encouraging. Xiong and his team proposed GECAM in 2016, the year when gravitational wave detectors of USA could do the historic discovery of black hole merger.

These are not enough; China has other missions to be launched in the near future. Xiong and his team has received a 4 billion-yuan (almost 610 million US dollar) funding for a five-year plan for four other space missions. Apart from GECAM, the NSSC is now developing the Einstein probe aimed to monitor the sky for detecting low energy X rays emanating from vigorous cosmic phenomena; the Advanced space-based Solar Observatory, aimed to observe sun’s magnetic field and hunt for solar flares along with a joint project with European Space Agency—the Solar Wind Magnetosphere Ionosphere Link Explorer, aimed at imaging the magnetosphere of Earth.

(With inputs from PTI)