Crew harvests rice samples on Tiangong

More than two months after arriving at the Tiangong space station, the Shenzhou XXIII mission crew has harvested the first batch of experimental rice samples after meticulously cultivating the plants in orbit.

A video released by the China Manned Space Agency on Sunday shows the astronauts — mission commander and spaceflight engineer Colonel Zhu Yangzhu, spacecraft pilot Colonel Zhang Zhiyuan and science payload specialist Lai Ka-ying — collecting and storing the rice samples.

The experiment, titled "Molecular Mechanism Study on Multigenerational Genetic Stability and Environmental Adaptation Regulation of Space Rice", aims to achieve the world's first continuous cultivation of two generations of rice in orbit, completing two consecutive life cycles.

Its primary objective is to reveal the biological mechanisms through which long-term exposure to microgravity affects the genetic stability of rice.

The rice seeds carried aboard the Shenzhou XXIII mission are Chinese japonica varieties known for their strong environmental adaptability and growth cycle of three to four months. They were divided into two groups: ordinary seeds that have never been to space and direct descendants of seeds harvested aboard the Tiangong space station in 2022 that have since undergone three generations of propagation on Earth.

According to China Central Television, the experiment consists of four independent cultivation units, each containing six seeds. The units are divided into two parallel groups, each testing a different rice reproduction method.

In addition to harvesting panicles and seeds, the astronauts will preserve stem and leaf samples at low temperatures for their return to Earth. Scientists will conduct detailed analyses of the samples to provide scientific support for developing production models for future space agriculture.

The latest experiment builds on earlier breakthroughs. In 2022, the Shenzhou XIV mission crew carried out the world's first full life-cycle rice cultivation experiment aboard the Tiangong space station. Six rice seeds spent 120 days in orbit and produced 59 first-generation space rice seeds, which were returned to Earth with the Shenzhou XIV astronauts.

Besides tending the rice experiment, Zhu and his crewmates carried out a series of scientific and medical tasks last week.

Working together, they used an ultrasound diagnostic device to conduct bilateral examinations of the carotid, radial and dorsalis pedis arteries. The data collected will support research on pan-vascular blood flow spectroscopy and the development of a spatiotemporal atlas of blood flow evolution.

The astronauts also carried out a lighting environment experiment by adjusting the space station's interior lighting and recording their work performance before and after the changes. The research aims to examine how lighting conditions affect psychological perception and work efficiency in the space environment.

The crew completed an in-orbit emergency rescue drill under a simulated fire scenario to strengthen their emergency response and fault-handling capabilities.

As part of their routine health management, the astronauts underwent a series of medical examinations, including electrocardiograms, vision tests, intraocular pressure measurements and fundus examinations. They also measured their body mass using a specialized mass measurement device to monitor physiological changes caused by prolonged exposure to microgravity.

zhaolei@chinadaily.com.cn