[ad_1]
The Perseverance rover is off to a good start for Mars. It’s more than halfway, in fact, in kilometers traveled. In 91 days – February 18, 2021 – it will begin its descent toward the Red Planet, plunging thin air into it at hypersonic speeds, slowing down to where a parachute can be used to slow it down further, then lowered by a sky powered by a rocket. crane on the surface.
Yes really. Do you remember seven minutes of terror? Literally the same thing here: Perseverance will use the same entry, descent, and landing (or EDL) sequence that Curiosity used.
One difference, however, is a specially installed microphone that will record the whole thing. He will hear the wind rush, the Celestial Crane shoot, and maybe even dust and sand rustle as it hits the ground.
But, on October 19, 2020, engineers here on Earth performed a check on various Perseverance systems, including the micro EDL. They turned him on and let him record what he heard.
And what he heard was the buzzing heat rejection fluid pump:
Now I know: the sound itself is a bit disappointing. But you have to understand what you mean. And why.
Martian winters are extremely cold. It’s not exactly Florida out there, even in the summer, but in the winter it’s cold enough to freeze carbon dioxide out of the air. A lot of the rover’s equipment will not perform well in this type of cooling and must be heated.
Fortunately, Perseverance takes a piece of plutonium with it.
Oh, didn’t you know that sucker was nuclear? Yep. Solar panels work on Mars, but the rover has a lot of moving parts that need more power than solar power can provide, so it has what’s called a radioisotope thermoelectric generator (or RTG), which uses the decay of plutonium to generate electricity. It’s very efficient – it generates 110 watts of power – and lasts a long time. They have been used successfully in many missions to the Outer Solar System, and have even been used by Apollo missions to the Moon.
It also generates a substantial amount of heat (worth 2,000 watts, roughly the same amount of heat 20 people give off just while living). So the rover is crossed by hoses filled with coolant (CFC-11 and Galden HT-170, if you must know – the chassis and some architectures of Perseverance are the same as for Curiosity). They take the heat from the RTG and distribute it through the rover where it is needed. Moving this fluid requires pumps to move it forward, and those pumps have parts that spin quickly, creating the purr that the mic picked up.
So that somewhat disappointing low and subdued buzz you’ve heard? These are actually fast-spinning parts inside a pump meant to move antifreeze around a nuclear-powered one-ton mobile chemistry mobile lab that will look for signs of really old life in a bed. dry lake on another planet. While he was still in space on his way.
Now does this sound have more impact?
You might be wondering why we’re hearing anything given that the rover is in the void of space. Sound needs a medium to pass through, some kind of substance, and for us on the surface of the Earth, it’s usually air. But sound can travel in water and even in solid, compressing and rarefying the material it passes through. The pumps push the fluid and the constant vibration of it is transferred through the body of the rover into the microphone. here. Sound.
Oh, by the way, there’s a second microphone on Perseverance, meant to listen to the SuperCam, an instrument located in the rover’s head, which also has a powerful laser that will zap rocks, vaporize them, and make them glow briefly. A spectroscope in the camera will then divide this light into colors that will allow scientists to determine what is in the rocks and at what abundances.
So Perseverance is actually a one-ton mobile chemistry mobile lab powered by a nuclear laser.
Cooool.
Finally, after saying all that, did you know that it is possible to make sound move in space? You just need the space not to be completely empty. In nebulae – gas clouds – the gas is incredibly thin, essentially a laboratory vacuum, with perhaps only a few thousand atoms per cubic centimeter. But when you’re a few light years away, it’s a lot cubic centimeters, which is a substantial amount of gas. It is dense enough that very low frequency sound waves (or long wavelength, if you prefer) can travel through them. These sometimes have visible effects, such as when a black hole carved out huge ripples in the surrounding gas, or even ripples made in the primordial plasma filling the Universe soon after the Big Bang (try dropping the phrasing baryonic acoustic oscillations in your next conversation).
Of course, these are pretty violent events. I guess if you do it hard enough in space, everyone can hear you screaming.
Or, in the case of Perseverance, hum quietly.
[ad_2]
Source link