Tardigrades lost on moon after spacecraft crash can survive for years in cryptobiotic state but not colonize: Experts
Beresheet - which means "in the beginning" in Hebrew - was touted to be the first Israeli spacecraft on the moon. The private mission by Israeli non-profit SpaceIL - successfully reached the moon - but mission control lost contact with the spacecraft, which subsequently crash-landed on the lunar surface April 11.
Besides the technology lost in the crash, the mission also lost a unique and uncommon payload: a few thousand tardigrades, probably the toughest animals on Earth. Known as water bears, tardigrades are tiny animals, with a high tolerance for freezing, radiation and desiccation (state of extreme dryness) - characteristics required to survive in space.
But can tardigrades survive on the moon? Dr. Łukasz Kaczmarek, a tardigrade expert and astrobiologist at the Adam Mickiewicz University in Poznań, Poland, told MEA WorldWide (MEAWW) tardigrades might be able to survive for some time on the moon (from a few months to a few years) if the container that carried them did not crash. However, they will not be able to reproduce or even be active on the moon.
What kind of conditions can tardigrades survive?
First discovered in 1773, they can be found all over the Earth and can inhabit very diverse environments - from the deepest oceans to mountain tops. Water bears are small, cylindrical invertebrates, up to approximately 1.5 millimeters in length and with very unique physiological abilities.
These species have developed a special skill that protects them against extreme environmental conditions - the ability to enter into a cryptobiotic state. According to experts, what this implies is a metabolic state of life an organism goes into in response to adverse environmental conditions such as extreme dryness, freezing and oxygen deficiency. In such a condition, all metabolic processes stop, preventing reproduction, development and repair.
Kaczmarek told MEAWW, tardigrades in cryptobiosis can survive up to 20 years in dry conditions and up to 30 years in a frozen state. They can also survive in liquid nitrogen (-253°C for 21 months) or in boiling water (at 151°C for 15 minutes).
They are able to survive dangerous chemicals - carbon dioxide, hydrogen sulfide, 1-hexanol, methyl bromide gas and 10 minutes in ethanol. Moreover, these creatures can also withstand large doses of radiation.
According to Kaczmarek, anhydrobiosis is the most studied form of cryptobiosis and occurs in situations of extreme dryness. Some animals like tardigrades can lose approximately 90% of the water from their body and survive (humans, for example, will die when they lose about 15%,). In such a state, they can survive in extreme conditions on deserts, polar deserts and severe freezing in ice, he explained.
So did they survive the crash?
Experts say if tardigrades remained in the container, they will probably be able to survive from a few months to a few years, but nothing more than that. According to astrobiologists, it is not that they are crawling around on the moon. Some experts said they may persist for several decades in a dormant state before dying.
According to Professor Lewis Dartnell from the Department of Life Sciences at the University of Westminster, tardigrades are known to be able to survive a whole range of environmental extremes – hot and cold, high levels of radiation and the vacuum of outer space. But Lewis said this is possible when they are in their so-called "tun" state – in times of stress the tardigrade rolls up into a ball and dries out.
“It’s almost like a state of suspended animation. It is in this tun state that they can survive the harsh conditions of outer space and not when they are active and crawling around. So although some of the tardigrades aboard the lander may have survived the impact into the lunar surface, they are in this dormant tun state – it’s not like they are alive and crawling around on the moon. They may persist for several decades on the moon in this dormant state before dying,” Lewis told MEAWW.
Kaczmarek explained that if the tardigrades were in an anhydrobiotic state, and if the box with the water bears survived, it is also possible the tardigrades survived. "But if the container with tardigrades was broken, they are probably dead. It depends on how strong the collision was," he told MEAWW.
"Tardigrades can survive on moon, but only in anhydrobiotic state. It also depends what species were sent to the moon because not all tardigrade species have the same abilities to survive desiccation and other extreme conditions in space," said Kaczmarek.
However, what is for sure is that tardigrades cannot colonize the moon due to the lack of an atmosphere and liquid water. "What can be said with certainty is that they cannot reproduce or even be active on the moon. The reason they cannot be active on the moon or survive for long is due to the conditions on the moon - low temperature and lack of water in the liquid state, as well as other extreme conditions," he added.
If they are brought back on Earth, however, and given water, it might be possible to bring them back to life, according to experts.