The way things behave in gravity may seem obvious to us after humans have ventured into space for more than 50 years.
But we were not always sure how space could affect certain things. Like fire. Or planar worms. Or even plants. It is only by doing experiments that we can learn the answers to these burning questions.
This led to some fascinating, sometimes disturbing and sometimes downright crazy experiments carried out in space.
A space suit is pushed out by an airlock
The video above plays out like something out of a nightmare. A space pack floats, unbound, away from the International Space Station (ISS), the big black gap that yawns for it.
You may be relieved to learn that no one was harmed during the making of this experiment – there is no one in the Russian Orlan suit, nicknamed Ivan Ivanovitch or Mr. Smith does not – it’s filled with a bunch of old clothes and a radio transmitter.
The idea was that old spacecraft could be used as satellites. SuitSat-1 – officially designated AMSAT-OSCAR 54 – was deployed on February 3, 2006, but the experiment was only partially successful; reports vary, with NASA claiming that the transmitter died shortly after release, and Russia reporting a final launch a full two weeks later. The last confirmed signal was received on 18 February.
SuitSat-1 spent several months in a quiet orbit before entering Earth’s atmosphere and burning on September 7, 2006.
The hammer and the spring
At the end of the 16th century, Galileo Galilei dropped two spheres of unequal mass from the Leaning Tower of Pisa in Italy. When both arrived at the ground simultaneously, he opposed classical views by showing that mass had no effect on gravitational acceleration. Even if the objects, regardless of mass, must fall at the same rate – even if they are a spring and a hammer.
On earth, it is difficult to demonstrate due to air resistance. But almost 400 years later, one repeats the experiment on the moon.
On August 2, 1971, Commander David Scott of Apollo 15 took a geological hammer in one hand and a falcon feather in the other. He lifted them to about 1.6 meters from the ground and dropped them. Because the astronaut was in fact in a vacuum, the two objects synchronized without air resistance.
“Within the accuracy of the simultaneous release, the objects were observed to undergo the same acceleration and hit the lunar surface simultaneously,” NASA astronaut Joe Allen wrote, “which was a result predicted by an established theory, but ‘ a result that is nevertheless reassuring both the number of viewers who watched the experiment and the fact that the trip to the country is critically based on the validity of the specific theory being tested. ‘
The hammer and feather are both still up there.
Fizzy tablet in a water leaf
If you spray some water out of a nozzle, it just hangs there, all blurry and wobbly.
It can be a lot of fun. Experiments and demonstrations included throwing water balloons into the vomit comet (the plane that makes parabolic flights to create short periods of free fall) and the ISS, and trapping a lump of water with a large bubble inside a loudspeaker make to observe the vibrations, and to place a GoPro camera in a water block to film it from the inside (you want stereoscopic 3D glasses for one).
In 2015, astronaut Scott Kelly colored a water block with food coloring, then inserted effervescent tablets and watched it dissolve and release gases into the water. It was filmed using the space station’s new 4K camera, so you can see the whole alien algae appeasing thing … in amazingly sharp resolution.
Fire in space
(ESA / NASA)
Just as water behaves differently in microgravity, so does fire. Fortunately, the 1997 Mir space station fire was a one-time event so far, but figuring out how fire behaves in microgravity can help plan fire safety for future long-term missions, such as the crew’s trip to Mars and the permanent lunar base. It can also help inform fire safety protocols down here on earth.
To that end, a number of ongoing research projects have studied what happens to flames in space. The combustion and suppression of solid state experiments on board the ISS investigated the combustion and extinction properties of a wide range of fuels in microgravity. Data from these experiments can be used to build more complex models to understand the finer details of combustion in the earth’s gravity.
Aboard the Cygnus cargo spacecraft, scientists in the Saffire experiments investigated how flames behave under different spacecraft conditions. And NASA’s research into flame design – part of the Advanced Combustion via Microgravity Experiments – examines the production and control of soot.
It is definitely very useful and interesting. But it’s also incredibly beautiful, and we bet there are some astronauts who are absolutely playing explosion in space.
Space spiders
In 2011, scientists answered the burning question: can spiders adapt to space travel? They sent two golden silk orchard spiders (Trichonephila clavipes), Esmeralda and Gladys, for a 45-day stay aboard the ISS.
They were kept in a nice habitat (you might think spiders are loose in a space station), with light conditions to simulate a night cycle, temperature and humidity control, and a healthy diet of juicy fruit flies.
Both spiders adapted beautifully and still twisted their webs and hunted for their food. Orb weavers eat their webs at the end of each day to regain protein, and turn it over again in the morning; also on this the spiders were still doing according to schedule, which was interesting since different bulbous species on the ISS just spun their web at any old time of the day.
But not everything was completely normal. In microgravity, the spiders spin their web images differently – flatter and rounder, compared to the more three-dimensional, asymmetrical structures that the spherical webs rotate on Earth.
The two spiders returned to Earth. Esmeralda perished on the return journey after she had a normal lifespan of the spider. Gladys returned hauls, but turned out to be a boy. He was renamed Gladstone.
Turtles go around the moon
In the 1960s, before humans were in the moon, it was not clear exactly how – if at all – to approach us personally from near the moon. In 1968, the Soviet space program sent two Russian turtles (Agrionemys horsfieldii) on a journey through Earth’s companion.
Actually, it wasn’t just turtles. Included in the flight were wine flies, mealworms, seeds, plants, algae and bacteria. There was also a dummy with radiation sensors, as none of the living organisms on board were remotely analogous to humans. According to a 1969 report, it appears that turtles were chosen because they can be fastened relatively easily.
The two unnamed reptile cosmonauts were placed aboard the Sin 5 spacecraft on September 2, 1968, on which they were no longer fed. They were launched into space on 15 September 1968 and returned to Earth on 21 September (in the Indian Ocean). They finally return to Moscow on October 7.
Their trip included seven days of space travel, a few days in tropical climates (including batting around in the ocean while waiting for recovery) and transportation back to Russia. Eventually, they spent 39 days without food. It will try anyone.
Control turtles that remained on earth were also deprived of food for the same period. A comparison of the two sets of turtles revealed that any changes in the spatial reptiles were mostly due to starvation, with a small contribution by space-related atrophy.
We want to say that no one ever sent turtles to space again, but unfortunately two more turtle missions took place. Sin 7 in 1969 bears turtles. In 1975, the Soyuz 20 spacecraft orbited a tortoise for 90 days. And two turtles flew in 1976 on the Salyut 5 space station.
Moon Trees
Just as we did not even know how space would affect animals, we were also unaware of its effects on plants. When the Apollo 14 mission was launched on January 31, 1971, the cargo contained something we can now consider a little peculiar: about 500 seeds.
U.S. Forest Service scientists wanted to know if tree seeds that flew in micro-gravity and were subjected to space radiation would sprout, grow, and look the same as seeds that never left the earth.
Five types of trees were included in the container: lobboline (Pinus taeda), California redwood (Sequoia sempervirens), American plane tree (Platanus occidentalis), Douglasspar (Pseudotsuga menziesii), and American sweet gum (Liquidambar styraciflua). They accompanied training module pilot Stuart Roosa on 34 orbits of the moon before returning to Earth.
The seeds were then planted and cared for, and most of them survived to grow into trees, along with the controls that had never left the earth. It is not surprising to us now that there was no distinction between the two.
By 1975, the lunar trees were large enough to be transplanted, and they were shipped all over America. According to this NASA website, less than 100 lunar trees can be taken into account today, of which only 57 lived when the page was compiled.
This means that there may be hundreds of lunar trees lurking in the US, a lost relic of a time when our curiosity caused small seeds to whistle in space. And we think it’s beautiful.