Tardigrades: the Future of Space Explorations ?
- Ana Binny
- Nov 2, 2024
- 4 min read
“Strange is this little animal, because of its exceptional and strange morphology and because it closely resembles a bear in miniature. That is the reason why I decided to call it little water bear.”
– J.A.E. Goeze (Pastor at St. Blasii, Quedlinburg, Germany), 1773
Before discussing how Tardigrades are opening up possibilities for manned space travel, let’s understand what they are and how they do what they do.
Tardigrades are microscopic eight-legged animals that have been to outer space and would likely survive the apocalypse. Bonus: They look like adorable miniature bears.
Around 1,300 species of tardigrades are found worldwide. They are considered aquatic because they require a thin layer of water around their bodies to prevent dehydration. They’ve also been observed in all kinds of environments, from the deep sea to sand dunes. Freshwater mosses and lichens are their preferred habitat, hence their nickname, the moss piglet.
Despite looking squishy, tardigrades are covered in a tough cuticle, similar to the exoskeletons of grasshoppers, praying mantises, and other insects to which they are related. Like those insects, tardigrades have to shed their cuticles to grow. They have four to six claws on each foot, which helps them cling to plant matter, and a specialized mouthpart called a buccopharyngeal apparatus, which allows them to suck nutrients from plants and microorganisms.
Now you might be thinking what is so special about these organisms … well you are in for a treat because Tardigrades belong to an elite category of animals known as extremophiles, or critters that can survive environments that most others can't. Their resiliency is in part due to a unique protein in their bodies called Dsup—short for "damage suppressor"—that protects their DNA from being harmed by things like ionizing radiation, which is present in soil, water, and vegetation.
Another amazing survival trick is cryptobiosis, a state of inactivity triggered by a dry environment. The micro-animals squeeze all the water out of their bodies, retract their heads and limbs, roll into a little ball, and become dormant. When conditions improve, they unfurl themselves and go about their business.
Now for the fun part. Just how hardy is the tardigrade? This question has intrigued scientists the world over for many decades – and boy, they’ve had a good go at testing the tardigrade’s limit.
Tardigrades have been known to survive:
• Low temperatures of 0.05 kelvins (-272.95 degrees Celsius or functional
absolute zero)
• High temperatures of 150 degrees Celsius
• Pressures of 40,000 kilopascals
• The burning ultraviolet radiation of space
• Being shot from a high-speed gun (traveling at nearly 3,000 feet per second
and the impact of 1.14 gigapascals of pressure)
• Being stored in a freezer for 30 years
And the Surprises don’t end there…
Tardigrades have been on earth for about 600 million years, preceding the dinosaurs by about 400 million years.
— American Museum of Natural History
They were first described in 1773 by German pastor J.A.E. Goeze, who called them kleiner Wasserbär, or “little water bear."
— SQ Online
The Israeli spacecraft Beresheet was carrying thousands of tardigrades when it crash- landed on the moon in April 2019. Later experiments show the animals likely died on impact.
— Science
There might be one thing tardigrades are not so well-equipped to handle: high temperatures over a prolonged period, per a study published in Scientific Reports in January 2020. The study revealed that this temperature-based Achilles’ heel also extends to when tardigrades are in their protective tun states.
Researchers studied Ramazzottius varieornatus, a species of tardigrade, in Tun state and noted nearly 50 percent of the tardigrades exposed to 181 degrees Fahrenheit over the course of an hour perished. Active tardigrades—that is, those not in tun state—fared even worse.
These temperature experiments show that given time, most tardigrades can adjust to intense temperature fluctuations: The tardigrades who had an hour to acclimate to intense heat faced higher mortality rates, compared to those who had a full 24 hours.
“Tardigrades can survive pressures that are comparable to those created when asteroids strike Earth, so a small crash like this is nothing to them,” Lukasz Kaczmarek, an expert on tardigrades, told The Guardian.
So what does this mean for us? If humans could replicate cryptobiosis in the way tardigrades do, we’d live far longer than the average life expectancy. According to Kaczmarek, when a tardigrade enters the tun state, it doesn’t age. It becomes dormant at one month old and can wake up years later and still biologically be the same age.
“It may be that we can use this in the future if we plan missions to different planets because we will need to be young when we get there,” said Kaczmarek.
So this is where we end up with. A new species is not that new and its ability to survive and prolong its lifespan by a significant percentage. Could these cuddly, odd-looking water bears be the answer for space travel or are we just as lost as we were in the beginning? With this thought, I'll leave you guys to judge the Indestructible Tardigrades.
Works Cited
Journey to the Microcosmos. “Tardigrades: Chubby, Misunderstood, and Not Immortal.” YouTube, 29 July 2019, www.youtube.com/watch?v=kux1j1ccsgg.
“This Is the Most ‘Indestructible’ Animal on Earth.” Animals,
Robertson, Lauren. “Everything you need (and want) to know about tardigrades - Front Line
Genomics.” Front Line Genomics, 26 July 2024, frontlinegenomics.com/everything-
you-need-and-want-to-know-about-tardigrades.
Herkewitz, William, and Daisy Hernandez. “Why Tardigrades Are So Badass: 7 Secrets of
the Only Animal That Can Survive in Space.” Popular Mechanics, 23 Jan. 2024,
Resnick, Brian. “Tardigrades — the microscopic, oddly cute toughest animals on Earth —
explained.” Vox, 8 Feb. 2018, www.vox.com/science-and-health/2018/2/8/16991280/tardigrade-facts-waterbear-explained.
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