Fish in Space: Space Station Gets an Aquarium

by Nancy Atkinson on July 27, 2012

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Caption: The Aquatic Habitat will enable the study of fish aboard the International Space Station. Credit: JAXA.

How does microgravity impact marine life? One of the more unique experiments on board the Japanese HTV-3 supply ship, scheduled to be berthed to the International Space Station’s Harmony node at 12:00 UTC on July 27, 2012, is the Aquatic Habitat, or AQH. It is basically an aquarium designed to function in space, complete with fish called Medaka. While there are several experiments planned for the AQH, surely the astronauts will enjoy watching their newest “pets” on the ISS.

Sponsored by the Japanese Space Agency, or JAXA, the AQH is a closed-water circulatory system, which provides a new facility option for station research. Scientists will use the habitat to study small, freshwater fish on orbit, the Medaka (Oryzias latipes).

This is not the first time fish have been part of a space mission. Versions of the AQH flew on space shuttle missions STS-47, STS-65, and STS-90. The current system’s design upgrades are based on lessons learned from these missions.

Scientists have multiple studies planned to look at the impacts of radiation, bone degradation, muscle atrophy, and developmental biology. The investigations could last up to 90 days and provide data that may lead to a better understanding of related human health concerns here on Earth.

“We think studies on bone degradation mechanisms and muscle atrophy mechanisms are applicable to human health problems, especially for the aging society,” said Nobuyoshi Fujimoto, associate senior engineer at JAXA’s Space Environment Unitization Center.

Fujimotoe said the Medaka fish are ideal specimens for many reasons. They are transparent, making it easy to view the inner workings of their organs. They also breed quickly and easily in microgravity environments, enabling multi-generation studies. Researchers can take advantage of a variety of genetic modifications to these fish, as well. Finally, scientists already have all of the Medaka genome identified, which makes it easier to recognize any alterations to the fishes’ genes, due to factors like space radiation.

The AQH will reside in the Japanese Experiment Module, or JEM, which is also known as Kibo, or “hope” in Japanese. It will attach to a multipurpose small payload rack for power and housing.

This habitat will provide automatic feeding for the fish, air-water interface, temperature control, and a specimen sampling mechanism. There will be two chambers for habitation, each sized at 15 by 7 by 7 cm, holding about 700 cc water and a stabilized area for oxygen that will enable fish to “peck” air. LED lights will simulate day and night cycles, while two video cameras record images of the fish to downlink to the ground, upon request.

This facility includes an improved water circulation system that monitors water conditions, removing waste while ensuring proper pressure and oxygen flow rates.

“In order to keep water quality in good condition for the health of the fish, we had to do many tests on the filtration system, especially the bacteria filter,” said Fujimoto. “The special bacteria filter purifies waste materials, such as ammonia, so that we can keep fish for up to 90 days. This capability will make it possible for egg-to-egg breeding aboard station, which means up to three generations may be born in orbit. This would be a first for fish in space.”

Hopefully the crew will enjoy viewing and monitoring the fish, and those of us on Earth look forward to some live views of the fish in microgravity.

Source: NASA

About 

Nancy Atkinson is Universe Today's Senior Editor. She also is the host of the NASA Lunar Science Institute podcast and works with Astronomy Cast. Nancy is also a NASA/JPL Solar System Ambassador.

Kevin Frushour July 27, 2012 at 11:36 AM

So how did the previous orbital fish fare? Did they swim upside down, etc?

squidgeny July 27, 2012 at 12:56 PM

Upside-down relative to what? ;)

I can only assume they did, unless they saw a reference point and decided to keep themselves aligned with it. Some fish have a habit of staying motionless even in a strong current – they’d need a reference point to do that, so maybe they could hijack that behaviour to keep themselves “upright” in microgravity.

zkank July 27, 2012 at 6:09 PM

No one will be aware of a fish dying in space since they can’t go “belly up”, and float to the top ;)

Kevin Frushour July 27, 2012 at 7:29 PM

Okay! Okay! :) Do they each orient in different directions?

John King July 27, 2012 at 9:06 PM

The way I’d understood it when reading up on this recently, was that the previous experiments had found that fish in orbit didn’t really require gravity to know which way was up. They know the ‘Sun’ is upwards, and align themselves according to any available light source…which is what the LED lighting is used for in this case I think. What’s really interesting is that this trait was observed in the fry that spawned in orbit also, which means this isn’t something the little fishies learn… It’s maybe passed on genetically… or we’re not the only ones that seem to adapt so well to the space.

I’m looking foward to when someone realises the potential of using aquaponics in space to grow fresh vegetables and fish on-site, while also acting as as O2 scrubbers for the humans living there… The fluid transfer is pretty much solved with this experiment, and now someone needs to work on making scaling/gutting a fish in microgravity not such an unplesent job! :(

Elias Barton July 27, 2012 at 11:53 AM

I suppose one can’t simply sprinkle fish food over the water during feeding time.

Torbjörn Larsson July 27, 2012 at 1:34 PM

Right, they have an airlock.

HeadAroundU July 27, 2012 at 2:38 PM

I grew up with guppies. Good memories. :d

Alea_Jacta_Est July 27, 2012 at 4:33 PM

It figures…

Kevin Frushour July 27, 2012 at 3:58 PM

Waterlock.

Torbjörn Larsson July 27, 2012 at 1:33 PM

I didn’t know that they had managed to develop healthy animals in space, but apparently Medaka has done so already 1995ish. I remember stories about plants having problem as they are using gravity to decide where the roots and stems go.

Medaka is small fry though and presumably full grown without relying much if anything on gravitational directionality, so it would be interesting to see development when they get to larger animals.

I stumbled on, and lost, a reference on some verification that Medaka uses the same regulative mechanisms for growing bones as we do. So that work will be more applicable than one could naively believe.

The air-water interface is inventive. They blow air into the transfer chamber to keep the water in the aquarium. Apparently it can be used as water rich terrarium for studying amphibians later on.

ClayCampbell July 27, 2012 at 3:33 PM

Aquarium VI costs 3000 credits on the Citadel. I wonder how much this one cost. ;)

Kawarthajon July 27, 2012 at 5:30 PM

Cool experiment. I wonder how they aerate the water without gravity?
Maybe a mission to Mars could have aquarium walls with these fish being raised for protein/fat rich food? That might help extend their food stores and give them protection from radiation. That would only work if it was more efficient to grow the fish food enroute than having to bring all of their food with them from Earth.

Aqua4U July 27, 2012 at 7:21 PM

I like it… fresh fish for the crew and radiation shielding from the water they swim in… right side up or up side down.. what makes a fish dizzy anyway? ….>}}}O>….

Anon Kopimi July 27, 2012 at 6:42 PM

Can they become sushi at mission-end time? Re-use, Re-purpose, Re-cycle!

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