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Amber Case via Flickr // CC BY-NC 2.0
Amber Case via Flickr // CC BY-NC 2.0

This Rocket Engine Design Would Turn Space Junk Into Propellant

Amber Case via Flickr // CC BY-NC 2.0
Amber Case via Flickr // CC BY-NC 2.0

With each passing year, the Earth's orbit becomes increasingly congested with hazardous space debris. The junk poses a real threat to spacecraft, and it's one that’s only expected to grow worse over time—the more debris that accumulates, the more collisions are expected to occur, eventually generating more debris and more collisions as part of a domino effect called the Kessler Syndrome. Scientists have been brainstorming ways to tackle this problem for years, and now one team from Tsinghua University in Beijing is proposing an idea for a rocket engine that converts space junk into propellant [PDF].

Spacecraft designed to rein in debris with a net or some other mechanism have been suggested in the past, but the issue has always been fuel supply. This rocket would help solve that problem by producing the energy needed to maneuver itself around via the space junk it cleared. The proposed rocket design relies on the scientific principle that any element can be transformed into a plasma of positive ions and electrons when heated at a high enough temperature. Using a net, the craft would harness debris less than 10 centimeters in size and transport it to a ball mill where it would be pulverized into a powder. The powder would then be heated and transferred to a system that separates positively charged ions from negatively charged electrons. A powerful electric field would accelerate the ions to high energy before expelling them as exhaust, thus producing thrust. 

Cornell University Library

It sounds straightforward in theory, but many of the crucial details would be harder to gauge. Factors like the size of the positive ions, the nature of the powder, and the density of the debris would all need to be calculated to get a better understanding of what type of thrust would actually be produced. And while the spacecraft would produce its own propellant, it would still require an energy source. The Tsinghua University team suggested nuclear power, but that would present an entirely new set of complications. It’s possible that the space-junk-eating engine will never make it into orbit, but it could inspire similar creative solutions to our planet’s growing space junk problem. And if worse to comes to worst, we always have giant lasers to fall back on.

[h/t: MIT Technology Review]

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The Fascinating Device Astronauts Use to Weigh Themselves in Space

Most every scale on Earth, from the kind bakers use to measure ingredients to those doctors use to weigh patients, depends on gravity to function. Weight, after all, is just the mass of an object times the acceleration of gravity that’s pushing it toward Earth. That means astronauts have to use unconventional tools when recording changes to their bodies in space, as SciShow explains in the video below.

While weight as we know it technically doesn’t exist in zero-gravity conditions, mass does. Living in space can have drastic effects on a person’s body, and measuring mass is one way to keep track of these changes.

In place of a scale, NASA astronauts use something called a Space Linear Acceleration Mass Measurement Device (SLAMMD) to “weigh” themselves. Once they mount the pogo stick-like contraption it moves them a meter using a built-in spring. Heavier passengers take longer to drag, while a SLAMMD with no passenger at all takes the least time to move. Using the amount of time it takes to cover a meter, the machine can calculate the mass of the person riding it.

Measuring weight isn’t the only everyday activity that’s complicated in space. Astronauts have been forced to develop clever ways to brush their teeth, clip their nails, and even sleep without gravity.

[h/t SciShow]

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Watch Astronauts Assemble Pizza in Space
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Most everyone enjoys a good pizza party: Even astronauts living aboard the International Space Station.

As this video from NASA shows, assembling pizza in zero gravity is not only possible, it also has delicious results. The inspiration for the pizza feast came from Paolo Nespoli, an Italian astronaut who was craving one of his home country’s national dishes while working on the ISS. NASA’s program manager for the space station, Kirk Shireman, sympathized with his colleague and ordered pizzas to be delivered to the station.

NASA took a little longer responding to the request than your typical corner pizzeria might. The pizzas were delivered via the Orbital ATK capsule, and once they arrived, the ingredients had to be assembled by hand. The components didn’t differ too much from regular pizzas on Earth: Flatbread, tomato sauce, and cheese served as the base, and pepperoni, pesto, olives, and anchovy paste made up the toppings. Before heating them up, the astronauts had some fun with their creations, twirling them around like "flying saucers of the edible kind,” according to astronaut Randy Bresnik.

In case the pizza party wasn’t already a success, it also coincided with movie night on the International Space Station.

[h/t KHQ Q6]

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