China considering mission to Ceres and large dark matter space telescope

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HELSINKI — The Chinese Academy of Sciences is considering potential missions including a Ceres orbiter and a huge telescope to hunt for clues about the nature of dark matter.

More than 20 candidates are vying for funding for further study under the Chinese Academy of Sciences (CAS) Strategic Priority Program on Space Science (SPP), also known as the New Horizon Program, and are currently undergoing evaluation.

The National Space Science Center (NSSC) in Beijing is expected to organize a panel of experts to review these pre-phase A candidates and make project priority recommendations in the second half of 2022. The selected missions could then move ahead with further study and potentially be developed into missions over the next decade.

A handful of the mission proposals are named in a paper on the progress of the third round of SPP mission selection published in the Chinese Journal of Space Science. These are the Very Large Area Gamma-ray Space Telescope (VLAST), a Space Weather program, a Ceres exploration program and a Gravity Experimental Satellite. 

The proposals cover the fields of space astronomy and astrophysics, exoplanets, heliophysics, planetary science, Earth science, space biology and fundamental physics. 

Few details are known at this point regarding most of the missions but the Ceres and VLAST missions appear to be more defined. 

It is understood the Ceres proposal would be an orbiter carrying a ground-penetrating radar as a main payload, focusing on the “origin of Ceres and its underground ocean and volcanic geological activities.” 

The only spacecraft to visit Ceres so far is NASA’s Dawn mission, approved under the Discovery Program and launched in 2007. Ceres is recognized as an ocean world with potential ongoing geological activity and could be further assessed for potential habitability. The mission could provide new insights in these areas, furthering understanding of Ceres and, by extension, ocean worlds and volatiles elsewhere in the solar system.

VLAST would seek to detect signals of dark matter in gamma ray emissions, following on from the DAMPE mission launched in 2015. It would also conduct gamma ray astronomy in the mega- and giga-electron volt range and make measurements of cosmic rays.

VLAST is expected to increase the sensitivity of the Fermi Large Area Telescope by a factor of 10, according to a paper in Acta Astronomica Sinica in May this year. The roughly 16-metric-ton observatory would need to be launched by a Long March 5 rocket. 

More immediately the CAS is evaluating 13 missions for possible implementation across 2025-2030 as part of the SPP III round of missions. 

From the candidates 5-7 missions will be selected from the fields of space astronomy and astrophysics, exoplanets, heliophysics and planetary and Earth science. Candidates include a Venus orbiter, an astronomy constellation in lunar orbit, exoplanet hunting missions, ocean and climate missions and solar observatories.

SPP III is an “effective approach to promote China’s space activities, and make great contributions to international space science and exploration,” according to the journal paper.

The emergence of the New Horizons Program shows China is also looking to develop medium-class missions alongside the flagship Chang’e lunar and Tianwen deep space missions and could add to its deep space exploration depending on mission selection.

The proposed CAS missions are also somewhat separate from, and additional to, the Chang’e and Tianwen missions, which are nominally under the aegis of the China National Space Administration (CNSA).

Tianwen-1 launched in 2020, sending an orbiter and rover to Mars. Tianwen-2 will be a combined near-Earth asteroid sampling and comet rendezvous mission launching around 2025, while Tianwen-3 is to attempt to collect samples from Mars and deliver them to Earth, launching in 2028. 

Tianwen-4 will launch a pair of spacecraft towards Jupiter around 2030. One will study the Jovian system and enter orbit around Callisto, with the other using a gravity assist to head for a flyby of Uranus.

SPP III follows on from a first Strategic Priority Program on Space Science which saw the DAMPE, HXMT, Shijian-10 and Quantum Experiments at Space Scale (QUESS) missions launched across 2015-2017.

The SPP II missions include the Einstein Probe, due to launch next year, the Electromagnetic Counterpart All-sky Monitor (GECAM) launched in 2020, the Advanced space-based Solar Observatory (ASO-S) launching this year, and the Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) in collaboration with the European Space Agency.