November 8, 2012
Thirty-five new occupants arrived at the International Space Station in late October. Three were astronauts, the rest were fish.
“This is the first experiment in the world to take care of animals for such a long time in the space station — for two months,” says Akira Kudo of the Tokyo Institute of Technology. “Normally, animals are cared for for just two weeks. Only astronauts stay longer than that.”
Kudo is the principal investigator for a study called Medaka Osteoclast, or MOST, examining how the bones of the medaka fish — also known as Japanese killifish, which are popular both as pets and research animals — will respond to microgravity. (Medaka fish were the first vertebrates to mate in space; four of them successfully laid and hatched eggs in an experiment aboard Columbia in 1994.)
The fish are living in a specially designed space aquarium called the Aquatic Habitat, partitioned into two, 1.5-pint sections. Housed in the Japanese Kibo module, the habitat has temperature control, water circulation and bacterial filtration systems, and an oxygen supply from a modified artificial lung machine. It also has an automatic feeder — no fish flakes floating around. Like diligent home aquarists, astronauts have to test and clean the water twice a week for the first three weeks, then three times every 14 days after that.
Japanese astronaut Aki Hoshide started the experiment by sacrificing and preserving eight of the fish in a stabilizing solution as controls, and moving 16 more from the transport unit into the Habitat. Today, after two weeks of swimming in microgravity, Hoshide removed six more medakas and preserved them in a type of formaldehyde; they’ll return with the astronauts next week on the Soyuz. Other station crew members will care for the remaining 10 fish, preserve them after 60 days, and send them back to Earth on a SpaceX Dragon capsule. Kudo plans to dissect them in ultra-thin slices to examine their bone densities.
His main goal is to understand the formation of osteoclasts, cells that absorb bone, and how microgravity affects the interaction between these and osteoblasts, bone-forming cells. Scientists already know that bone density decreases in space, and Kudo suspects it has to do with increased osteoclast production.
Medaka fish are particularly useful for this study because they’re transparent, which allows easy viewing of their bones and organs. They are also easy to modify genetically: those aboard the station have fluorescent proteins that cause osteoclasts to glow green and osteoblasts to glow red. (How nice that they’ll be aboard for Christmas!)
The aquarium also is set up for observation. Astronauts and scientists on the ground are able to watch the fish swim in loops, rather than in straight lines, because there’s no sense of up or down to orient them. The medaka are rapid breeders, so there’s a strong possibility for fish fry (fish babies, that is, not a dinner buffet) in space, up to three generations in the time they’ll be aboard — that would be a first for space fish. Further experiments will study organ formation, and the aquarium is also designed to house frogs.
At JAXA’s Tsukuba Space Center, Kudo can watch a live video feed to check whether the fish are swimming and eating normally. The medaka are already of great interest to the six space astronauts, who can look in on the fish as they go about their work. Kudo says: “We call them fishonauts.”
November 2, 2012
In space, a drop of fuel burns in a sphere, symmetrically sucking in oxygen and producing heat and gas equally on all sides. With no gravity to make hot gas rise, flames lack the teardrop shape they assume on Earth. “It’s a ball of fire, more or less,” explains Forman Williams, a combustion researcher at the University of California, San Diego.
Williams is the principal investigator for Flame Extinguishment Experiment 2, or FLEX-2, which studies these fireballs on board the International Space Station. Williams hopes his experiment will provide insight into the basic physics and chemistry of combustion, and lead to improved fire safety in space.
FLEX-2 takes place in the 560-pound Combustion Integrated Rack, which is located in the station’s Destiny lab module. Inside the rack, an apparatus about the size of a bread box can be filled with different mixtures of oxygen, nitrogen and helium gas. Tiny droplets of fuel, like methanol or heptane, are dispensed into the combustion zone through a syringe. “Since there is no gravity, the droplet just sits there,” Williams says. The droplets are ignited and can burn for up to 20 seconds or so (the exact time depends on the gas and fuel), shrinking as the fuel is consumed. While one camera records the droplet size, radiometers and an ultraviolet camera record the flame radiation, and another visible-light camera records the droplet and the flame.
Last summer, astronauts completed multiple rounds of experiments, typically doing four to 10 droplet burns in a session, twice a week. The first FLEX experiment studied the physics of flame extinction — how flames die out when there’s not enough fuel or oxygen — and was geared toward spacecraft safety. FLEX-2 is “more science-oriented,” says Williams, and is investigating fuel mixtures that might be used in high-efficiency automobile engines.
In the video above, a suspended droplet of heptane burns for a couple of seconds in a “hot flame,” then — when the scene appears mostly dark — burns in a “cool flame,” a steady, lower-temperature combustion. Finally, the droplet extinguishes in a bright orange vapor cloud.
The team has already made one interesting observation. “We were burning these heptane droplets out there on station, and we saw the hot flame extinguish, but the droplet kept decreasing in size. It was just like if it was burning, but we could not see any flame — it was almost like an invisible flame was causing these heptane droplets to burn steadily,” Williams says. “We didn’t even believe it for a year.” The team’s research was published in the December 2012 issue of the journal Combustion and Flame.
“Cool flames” have long been known to exist, but understanding more about how they work could help in the development of efficient, low-emission engines. Alternative fuels used by these types of engines often produce cool flames during combustion.
“If we hadn’t done these experiments in station, this phenomenon [that cool flames can support steady droplet combustion] would not be known today, so we were really excited about that,” Williams says.
Rebecca Boyle is an Air & Space contributor based in St. Louis.
September 10, 2012
Shortly after Japan’s Kounotori cargo ship undocks from the space station on Wednesday, ground controllers will fire its rockets to steer the schoolbus-size craft into the atmosphere so that it burns up over the ocean. Normally, the end would come discreetly off camera. This time, we’ll get to watch the fireworks.
In the 55-year history of satellites re-entering the atmosphere, nobody (or at least nobody in the unclassified world) has ever gotten pictures from the satellite’s point of view. For Kounotori’s demise, Japanese investigators have placed a camera-equipped device called i-Ball inside the spacecraft. The spherical i-Ball has two cameras. One will return 10 images from inside Kounotori as it’s breaking up. The second camera will take 40 pictures after the breakup, and the i-Ball will continue on to a splashdown in the ocean.
This Japanese space agency video shows how it’s all supposed to go:
Japan’s i-Ball won’t be the only instrument recording the spacecraft’s breakup. Another experiment package, called REBR (Re-Entry Breakup Recorder), will collect information on temperature and accelerations as Kounotori is torn to pieces during re-entry.
“Getting data off a satellite that’s coming in and breaking apart is a bit of a trick,” says William Ailor of The Aerospace Corporation, principal investigator for REBR, whose team worked on the technology for more than a decade before flying it for the first time on another Kounotori last year. REBR is contained in a copper shell held together by plastic bolts. Once the spacecraft starts to break up, the bolts melt and the instrument package is set free. “The whole vehicle that we’re riding in has to come apart for us to get out at all,” says Ailor. REBR has no cameras, but its data — transmitted to the ground during a five-minute fall to the ocean — will tell scientists about the timing and conditions of the breakup.
Why do they care? Currently, spacecraft operators err on the side of caution when it comes to de-orbiting a satellite at the end of its lifetime. Rather than risk an uncontrolled entry over a populated area, they command the satellite to re-enter slightly early. “If your casualty expectation exceeds 1 in 10,000, you have to put it in the ocean,” says Ailor. The risk of casualties is based on estimates of when a given satellite would break up as its orbit decays. “What we’re trying to do [with REBR] is calibrate the models that make these estimates.” If satellite owners could be less conservative in their estimates, they could leave valuable satellites — say, the Hubble Space Telescope — operating longer in space.
Information on satellite breakup is considered important enough that a commercial venture called Terminal Velocity Aerospace has licensed the technology from The Aerospace Corp. to do routine data collection on future spacecraft. Meanwhile, Ailor is looking forward to i-Ball’s first-time photos. “I hope they succeed,” he says. “That will be really significant in itself.”
Below: In 1984, cameras in Hawaii captured the space shuttle’s external tank breaking up over the ocean. The STS-41C astronauts narrated video of the re-entry during a postflight press conference:
In 2008, the European ATV cargo vehicle was filmed during re-entry:
July 31, 2012
Conversation overheard this morning between astronaut Suni Williams, onboard the International Space Station, and NASA’s payload science center in Huntsville, Alabama:
Huntsville: We did see [on video] Nefertiti eating a fly.
Williams: Did she jump to get it? How did she get it?
Huntsville: She did jump, she’s adapting well.
Williams: Pretty awesome!
This is exciting news, presumably, to 19-year-old Amr Mohamad of Alexandria, Egypt, whose investigation of the weightless eating habits of two jumping spiders* named Nefertiti and Cleopatra was one of three winners of the global YouTube Space Lab competition for high-school students. Mohamed’s experiment arrived on the station just a few days ago on a Japanese cargo ship, and here the spiders are already munching away on fruitflies.
Mohamed thought Nefertiti and Cleopatra, who jump on their prey rather than trap them, would find zero-g hunting to be more of a challenge. Here’s his experiment proposal:
*Note: An earlier version of this post misidentified both spiders as zebra spiders. Nefertiti is a redback jumping spider.
July 24, 2012
If the spirit of the Olympics lies in nations coming together, than what better place to celebrate that spirit than the International Space Station? As current crew member Suni Williams told CollectSpace, ”I think the International Space Station and Olympics are very similar in that they bring together countries from all over the world. They work together, they compete and they bring out the best in each other.”
For as long as the station has been inhabited, astronauts have been sending messages to the athletes almost every summer and winter games. For the upcoming London games, the six astronauts in low-Earth orbit recorded a prime-time, go-get-’em hurrah with Brian Williams of NBC’s Nightly News that will air on an upcoming show, and another that will run during Friday’s opening ceremonies.
And that’s not the only way NASA has made its mark on the Olympics. In Beijing in 2008, Michael Phelps became the winningest Olympian ever, wearing a swimsuit that had design help from an aerospace engineer at the Langley Research Center in Virginia. The 1998 U.S. Speedskating team brought home two medals thanks in part to a polishing process created by a former NASA engineer, one of the many space program innovations put to use elsewhere, called “spin-off technologies.”
When Atlanta hosted the 1996 games, NASA and the FAA used the chaotic air traffic as an opportunity to test new developments in communications, navigation, and surveillance systems. Fifty helicopters providing support for the Olympics were part of Operation Heli-Star, whereby they were equipped with newly designed digital data-link systems and GPS, providing a real-world test before the equipment was put into general aviation use.
In the less practical, but more visually awesome category, NASA created these killer zooms of Olympic sites from space. Using a combination of images from Terra, Landsat 7, and the commercial satellite Ikonos, we got a “camera dropped from space” view of the 2002 winter games in Salt Lake City, Utah. Our favorite is probably this drop to the summit of the Snow Basin Ski Area…which almost makes the skiers high-speed race down the mountain seem easy by comparison. (Alright, not really.)
And of course, astronauts freed of the bonds of gravity usually can’t resist staging some athletic competitions of their own. We’d be surprised if Williams, a marathon runner, doesn’t have something similar in mind for the London games.
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