The first 20 star-trekking mice to travel to the International Space Station, riding aboard a spacecraft built by Hawthorne-based Space X, have returned to their home lab at UCLA.
But the mission isn’t over for the mice, plucked last week from their capsule in San Pedro, according to a scientist participating in the project that aims to help humans battle bone loss.
For now, the pioneering rodents are awaiting their rodent counterparts, still orbiting 220 miles above Earth on the space station’s National Lab. And they’re getting reacquainted with life back on Earth, dealing with such challenges as normal gravity.
Altogether, 40 mice will continue to be treated with a protein therapy that has shown promise regrowing lost bone.
The mice passed through the Earth’s 3,000-degree Fahrenheit atmosphere at a rate of force equal to about five times their body weight — without injury, scientists said.
They took to life in space pretty well, said Louis Stodieck, director of BioServe Space Technologies at the University of Colorado Boulder’s aerospace-engineering sciences division.
“They looked really good. They were very healthy,” said Stodieck, who came to UCLA to help acclimate the mice to life on Earth again. “Mice are very capable.”
During their travel, they lived inside a specially made, jungle-gym-like habitat and ate moist, nutrient-rich food bars developed by NASA. (“Think of a power bar but not quite so sweet,” Stodieck said. “The mice love it. It’s very good, I’ve actually tried it.”)
Like returning astronauts, the mice-tronauts appeared initially unsteady in gravity. Their space habitat had mesh walls, allowing them to crawl around with stability.
“They get so adapted to microgravity, that gravity probably feels a little hard,” Stodieck said. “They looked a little bit tenuous, but they’re getting used to it.”
‘Learning a lot’
Since the Soviet Sputnik program returned the first animals — dogs, rodents and insects — from a brief trip around the Earth in 1957, the U.S. Space Shuttle program has gone on to return animals from rocket trips.
But these are the first U.S. rodents to participate in a lengthy microgravity research trip, and to board the space station’s National Laboratory, Stodieck said.
“These studies, with animal models, are few and far between. They are difficult and expensive,” he said. “It’s very important for us, in any of these studies, to maximize their scientific utility. The space station is a tremendous laboratory platform. We’re learning a lot of things.”
Increasingly, researchers are studying the effects of microgravity on stem cells to understand the full potential of space research.
But the mice are promising some exciting results that could help many people on Earth, according to the scientists.
Astronauts (and mice-tronauts) experience severe bone loss when they travel outside Earth’s gravity-laden atmosphere.
Floating around in microgravity not only depletes bone mass, it also weakens muscles, most notably, heart muscles. The recent mission also carried hundreds of fruit flies for an investigation into the effects of microgravity on the cardiovascular system.
“With the Space Shuttle program, we were only able to do relatively short (orbital research) durations (with animals),” Stodieck said. “We weren’t able to let them adapt over a long period of time. This duration of exposure was the first time we’ve been able to do a detailed, controlled study” with animals in space.
Robust rocket recycling
SpaceX’s reusable rockets and spacecraft are enabling U.S. researchers to send experiments to orbit affordably from America for the first time in years.
The Dragon craft that returned the mice to Earth previously flew to the Space Station in 2014.
SpaceX’s business model relies on such high-tech recycling. And spacecraft that are quickly reusable are key to future scientific research in space, Stodieck said.
“We’re now able to look at the recovery of animals and compare it with counterparts continued to be housed in microgravity conditions,” Stodieck said. “On the space station, we can watch their behavior with infrared LEDs. The mice adapt to microgravity very quickly. By the time we see them for the first time (after their rocket ride), they’re eating, drinking and grooming — they’ve already adjusted to their environment very well.
“In fact, a crew member commented that they adjust the way they move around in space basically the same way the astronauts do. They use their legs for balance and arms to move around.”
