Kasper>>What happens to metals when they're at 1700 degrees C being hit by sunlight and
particle radiation? How do you know it won't just evaporate? How do you convince
NASA and reviewers that it will actually survive? The Sun is one of the most
fascinating mysteries in our solar system, and thanks to the Parker Solar Probe,
we may start to understand it a little better. The plan is to send a spacecraft
the Sun's corona to measure the electric and magnetic field, image the solar wind,
and collect high-energy solar particles. Then, it will send back the solar data to
help researchers better forecast Solar Flare activity and how that might affect
us here on earth. The probe team needed to prove that their instruments could
withstand the harsh conditions of the Sun. Justin Kasper is responsible for the
probe's Faraday cup which is designed to scoop up the solar wind. >>So a French
colleague of mine in Paris said, you know, 'Okay. Meet me in Perpignan (which is a
small town on the on the coast in southern France).' So like a couple months
later, I hop on the plane, I fly down there and I meet him. We hop in a car
three hours later were up in the Pyrenees. Get out of the car, there's a half a
foot of snow. I'm in shorts, miserable, but we're
looking at the largest solar furnace in the world.
The Audeo solar furnace is located in the Pyrenees Mountains in southern
France. There are 63 mirrors on the mountainside that reflect the sun's rays
to a seven-story parabolic structure fitted with ten thousand mirrors. The solar
rays are then reflected and focused to a central tower. >> My colleague and the
people that work there said, 'Come with a prototype of your instrument, stick it in
this chamber, and we'll expose it up to, you know, the full amount of sunlight it
would experience at closest approach. We'll heat it to the full temperatures. We can
simultaneously hit it with the radiation of an experience close to the Sun, and
will do it for you for free.' And they showed me a memorandum from the 1970s
and it said you know we the French Space Agency would love to be involved in the
Solar Probe one day if it ever happens. So here's the agreement we've made: we're
gonna go off and we're gonna figure out how you can show these things can
survive that's a kind of extreme environment, and if one day,
Solar Probe really happens and you want to design these instruments, you come to
us and and we will have a facility where you can test these materials. And so
they'd been waiting for like 40 years for someone to show up and say, you know,
okay, I've got it. And so it was a wonderful experience. In the end they
wound up testing more than 300 different material samples for us, you know, all
using this light bouncing off these mirrors and the Pyrenees. NASA needed
further testing to ensure the probe could withstand days of exposure to the
solar elements in space. >>So we're just three months away from the launch of
Parker Solar Probe. We have one last test to do for our instruments on the
spacecraft, and that's to take our qualification model the Solar Probe cup,
put it in this chamber behind me, and simulate an encounter with the Sun.
Researchers put the Faraday cup in a vacuum chamber and blasted it with light
and radiation as powerful as the Sun.
Then the team bought four used IMAX film projectors on eBay, and hacked them to
create the intense focused light. "If you look at an old-school analog 70
millimeter IMAX film projector that has a bulb full of xenon it heats up to
about the same temperature as the surface of the Sun, we have to combine
four projectors to get the total amount of sunlight and the the angular size of
the Sun correctly, but we shine that merged sunlight in through this window
into the chamber and illuminate the instrument with it. Outside the vacuum
chamber, we have this dull-looking metal box here, which is actually a replica of
the spacecraft. So the instrument actually thinks it's on the spacecraft,
talking to the spacecraft, sending it telemetry. We're now very much
simulating the real Sun environment. The next steps, now that the chamber pressure
is dropping, we can bring our ion gun or particle accelerator on and see if the
instrument functions. So now that we've turned on the instrument it's reporting
internal Diagnostics, and one of the things we're seeing is the electronics
are actually pretty warm. We really don't have a lot of time to do our tests
before the electronics risk overheating, so we're gonna have to move pretty
quickly. Chamber pressure is a little on the high side, which is fine, but the
particle accelerator actually has its own circuit that won't allow us to
enable the accelerator if it thinks the pressure is too high. So, we've got to
basically flip a switch to override that interlock device so we can turn the
particle accelerator on. Meanwhile, the temperature of the electronics box keeps
rising. We managed to just correctly reprogram the
interlock, so the particle accelerator is not being inhibited from turning on.
We're gonna set up a data display, so as the instrument scans through voltage,
we'll see if there's an IM beam or not. Done? Yay! Alright! Haha.
That's a nice, really strong signal. If you look, you know, the signal is coming in
really clear, really strong, coming in at the exact same energy every time, and
we've reached a point where the instrument is able to outperform the
conditions that the chamber is capable of recreating. It's just about as good as
it gets. What more do you want when you're trying
to show that an instrument is gonna operate in an extreme environment than to
build the best test facility you can to recreate that environment, then see if
the instrument is able to outperform that. Yeah! We're going to the sun. We're going to the sun.
That's exciting.