Brought to you by Newscorp Australia

Mighty mice keep muscles in space

AP, September 8, 2020 7:05PM Kids News

Print Article

Knowing how to keep astronauts strong and healthy is important if take long trips in space, such as to Mars. media_cameraKnowing how to keep astronauts strong and healthy is important if take long trips in space, such as to Mars.


Reading level: orange

Bulked-up “mighty mice” held onto their muscle during a month-long stay at the International Space Station, returning to Earth with ripped* bodybuilder physiques*.

Study results hold promise for preventing muscle and bone loss in astronauts on long space trips such as Mars missions, as well as people on Earth who are confined to bed or need wheelchairs.

A research team led by Dr Se-Jin Lee of the Jackson Laboratory in Connecticut, US sent 40 young female black mice to the space station in December, launching aboard a SpaceX rocket.

You can read the Kids News story about that trip to the ISS HERE

In a paper published in the Proceedings of the National Academy of Sciences, Dr Lee said the 24 regular untreated mice lost up to 18 per cent muscle and bone mass in weightlessness as expected.

But the eight genetically engineered* “mighty mice”, which launched with double the muscle, maintained their bulk. Their muscles appeared to be comparable to similar “mighty mice” that stayed behind at NASA’s Kennedy Space Center.

In addition, eight normal mice that received “mighty mouse” treatment in space returned to Earth with dramatically* bigger muscles. The treatment involves blocking proteins* in the mice that can limit muscle mass.

This August 2020 photo provided by Dr. Se-Jin Lee shows a normal mouse and a “twice-muscled” mouse developed at the The Jackson Laboratory of the University of Connecticut School of Medicine in Farmington, Conn. Findings published on Monday, Sept. 7, 2020, show that muscle-bound mice, similar to the one pictured, held on to their bodybuilder-type physiques during a one month space mission. (Dr. Se-Jin Lee/University of Connecticut School of Medicine via AP) media_cameraA “twice-muscled” mouse (left) and a normal mouse. Muscle-bound mice, similar to the one pictured, held onto their bodybuilder-type physiques during a one month space mission. Picture: Dr Se-Jin Lee/University of Connecticut School of Medicine via AP

A SpaceX capsule brought all 40 mice back in good condition, parachuting into the Pacific Ocean off the US west coast in January. Some of the ordinary mice were injected with the “mighty mice” drug after returning and quickly built up more muscle than their untreated companions, Dr Lee said.

The scientists completed the experiment just as the coronavirus was hitting the US.

“The only silver lining of COVID is that we had time to write it up very intensively” and submit the results for publication, said Dr Emily Germain-Lee of Connecticut Children’s Medical Center, who is also Dr Lee’s wife.

While encouraged by their findings, the couple said much more work needs to be done before testing the drug on people to build up muscle and bone, without serious side effects.

“We’re years away. But that’s how everything is when you go from mouse to human studies,” Dr Germain-Lee said.

Back view young adult girl doing barbell squats media_cameraWeight training and weight-bearing exercise necessary to build and maintain muscle and bone density doesn’t work in space with reduced gravity, like it does on Earth.

Dr Lee said the experiment pointed out other molecules* and signalling pathways worth investigating — “an embarrassment of riches … so many things we’d like to pursue.”

His next step: possibly sending more “mighty mice” to the space station for an even longer stay.

Three NASA astronauts looked after the space mice, performing body scans and injections: Christina Koch and Jessica Meir, who performed the first all-female space walk last October, and Andrew Morgan. They are co-authors of the research paper.

media_cameraNASA astronaut Jessica Meir inside the Soyuz MS-15 capsule shortly after landing in Kazakhstan, on April 17, 2020 after her return from the International Space Station. During her time in space she looked after the 40 mice and contributed to the research paper about the study. Picture: AFP/Russian Space Agency Roscosmos/GCTC/Andrey Shelepin


  • ripped: a slang term for having big, well-defined muscles
  • physiques: body shapes
  • genetically engineered: changing a living thing’s genes
  • dramatically: noticeably, fast or a lot
  • proteins: substance in living things that help repair or make new muscle and bone
  • molecules: tiny particles made up of two or more atoms


Worms and mice at International Space Station

Female astronauts make ‘herstory’ on space walk

What it takes to become an astronaut

Hibernation for astronauts


  1. Why could we need to know how to keep astronauts strong while in space?
  2. What, back on Earth, could this research be useful for one day?
  3. Where in space were the mice?
  4. How did the mice travel back to Earth?
  5. Who looked after the mice in space?


1. Health in Space
Think about the astronauts on-board long missions to space that can last from months to years. What things would you need to consider to ensure they remain healthy in mind and body? Ensure you include things that they would need to substitute that they can’t get in space, such as sunlight. Work with a partner to fill out the chart below.

Work with a partner to fill out the chart above. media_cameraWork with a partner to fill out the chart above.

Time: allow 20 minutes to complete this activity
Curriculum Links: English, Health and Physical education, Critical and creative thinking, Personal and social

2. Extension
How can you see this drug helping people whose muscles start to waste away if they are confined to a bed or in a wheelchair?

List some possible positives and negatives of this drug being approved for human use.

Time: allow 15 minutes to complete this activity
Curriculum Links: English, Critical and creative thinking

An adjective is a describing word. They are often found describing a noun. To start with look at the words before the nouns.

Search for all the adjectives you can find in the article

Did you find any repeat adjectives or are they all different?


Pick three of your favourite adjectives from the text and put them in your own sentences to show other ways to use them.

Have you used any in your writing?

HAVE YOUR SAY: How do you feel about this experiment?
No one-word answers. Use full sentences to explain your thinking. No comments will be published until approved by editors.

Extra Reading in space