The secrets of the Parker Solar Probe, the engineering prodigy that “touched” the Sun without melting

  • 12

When it comes to solving mysteries of the universe, human beings have an impressive capacity to try to achieve it. The origins of astronomy are almost as old as our history. And, when it was no longer enough for us to look up, we decided to get closer to the stars. ‘Ad astra per aspera’ reads a plaque located at NASA Launch Complex 34 that pays tribute to the Apollo 1 astronauts and reminds us of our insatiable thirst to pursue the unknown.

Since the early days of space exploration, we have launched satellites, built space stations, walked on the moon, and even sent probes deep into our solar system. In 1957, the Fields and Particles Group of The National Academy of Sciences proposed a mission with a solar probe “to study the particles and fields in the vicinity of the Sun.” However, it wasn’t until 2018 that this idea finally came to fruition with the launch of the ambitious Parker Solar Probe.

The probe of “only” 1,500 million dollars

NASA’s budget to explore the Sun hasn’t been as big as the $10 billion for James Webb or the $35 billion from the Artemis Program. parker solar probe has managed to “touch” the star king with the modest amount of $1.5 billion. This abysmal difference in the budget does not mean that the mission has been easy. On the contrary, obstacles have had to be overcome that, until recently, seemed impossible.

One of the challenges that was on the table was to make the probe reach the Sun. Saying it may seem easy, but doing it is too complex. After a long time of research, the engineers came up with a plan that worked perfectly. On August 12, 2018 they launched the probe aboard a United Launch Alliance Delta IV Heavy rocket and used the planetary assistance of Venus’ gravity to make it complete several passes over our star.

Now, there was no point in sending a probe to the Sun without taking its extreme temperatures into account. Certainly, the teams responsible for the Parker Solar Probe also thought about this so developed a heat shield capable of reflecting heat at the front of the ship and keeping equipment at reasonable temperatures at the rear. The shield and how it interacts with the environment is one of the most amazing things about this project. Let’s see.

Parker Probe Nasa Sun Thermal Shield 1

The probe’s heat shield is made up of layers of different materials. The heart of this piece is carbon foam with 97% air, very similar to that used in the medical field for bone replacement. The foam, as if it were a sandwich, is surrounded by sheets of composite carbon with insulating properties. Lastly, a layer of ceramic paint was applied to the Sun-facing part of the shield to reflect as much heat as possible.

Parker probe 12

As we have said, this spacecraft has been designed to “touch” the Sun, which is equivalent to entering its outer atmosphere, also known as the corona, which It is over a million degrees Celsius. Yes, you read correctly, it is at an incredibly high temperature. You may be wondering, then, how a device made on Earth is able to function in a million degree Celsius atmosphere. The answer lies in thermodynamics.

Let’s review some concepts. The second law of thermodynamics, roughly speaking, tells us that heat always flows from the hottest to the coldest substances. Taking this into account, we understand heat as the transfer of thermal energy between the molecules of a system and temperature as a physical property measurable in Celsius, Kelvin, Fahrenheit or Rankine. Namely, heat is not the same heat as temperatureand here we will see why this is important.

Heat is not the same heat as temperature.

Although the Sun’s corona has a very high temperature (more than a million degrees Celsius), the plasma particles that make it up are quite dispersed, so heat transfer (thermal energy) is low. This means that the low density of the outer atmosphere of our star makes the Parker probe only have to withstand about 1,377 degrees Celsius and that the hardware inside the ship can work at about 28 degrees Celsius.

As we can see, only a part of the ship is protected from the Sun. In this sense, the Parker solar probe must ensure that it always has the correct direction to prevent excess heat from damaging its components. To do this, it has been equipped with a series of sensors that protrude from the protection shield. If they are illuminated by sunlight, the probe automatically corrects its trajectory to stay safe.

Parker probe 14

But the protection system is not everything in the Parker solar probe. The accompanying instruments are allowing us to better understand the Sun. main scientific objectives of the mission They are to trace how energy and heat move through the solar corona and to explore what is the origin of the acceleration of the solar wind and solar energetic particles. Let’s see what those instruments are.

The Parker Solar Probe carries four sets of instruments.

FIELDS. A trio of magnetometers is responsible for capturing the scale and shape of the electric and magnetic fields in the Sun’s atmosphere. Here we first meet a search coil magnetometer that measures how the magnetic field changes over time. Its operation is very simple. Since magnetic fields induce a voltage in the coil, scientists measure that voltage to obtain data on magnetic field variations.

We also have two saturation magnetometers (fluxgate), one internal (MAGi) and one external (MAGo). These have the ability to measure the farthest magnetic field from our star, where it varies at a slower rate. To eliminate any type of error in the measurements, the team in charge of designing and building this instrument, the Space Sciences Laboratory of the University of California, used antennas to place the sensors at 190 and 272 cm distance from the probe.

WISPR. Although the probe has to endure extreme conditions when visiting the Sun’s atmosphere, it can capture images thanks to a suite of sophisticated instruments that hide behind the heat shield to block most of the Sun’s light. These are two cameras with detectors CMOS Active Pixel Sensor reinforced to withstand radiation. The lenses are made of BK7, a radiation-resistant optical glass that we’ve also seen on the Hubble Space Telescope.

Sweap Suite Solar Probe 1

SWEAT. The objective of this set of instruments is to study the most abundant particles in the solar wind (electrons, helium ions and protons) and measure properties such as speed, density and temperature. To get it, the scientists resorted the Solar Probe Cup (SPC), a metallic device known as a Faraday cup that can trap charged particles in a vacuum, and the Solar Probe Analyzers (SPAN-Ai and SPAN-B) that use curved plates to measure particle distribution.

ISʘIS. This is one of the most ambitious sets of scientific instruments in the program. Its mission is to measure electrons, ions and protons in the Sun’s atmosphere and understand a wide range of questions behind these particles. The questions scientists are trying to answer are where they come from, how they accelerate, and how they move away from the sun into interplanetary space. To advance in this research, there are instruments that are key.

Artemis: dates, plans and everything we know about the mission to return man to the Moon

We are talking about two devices that have been designed and built by the Johns Hopkins University Applied Physics Laboratory. On the one hand, we have EPI-Lo which measures ion and electron spectra and identifies carbon, oxygen, neon, magnesium, silicon, iron and two isotopes of helium, He-3 and He-4. On the other hand, we have EPI-Hi, which uses three particle sensors composed of stacked layers of detectors to measure particles with energies higher than those measured by EPI-Lo.

Images: Johns Hopkins University | POT | Harvard University

In Xataka: Artemis I has finally lifted off: these are the next steps of the mission from now on

When it comes to solving mysteries of the universe, human beings have an impressive capacity to try to achieve it.…

When it comes to solving mysteries of the universe, human beings have an impressive capacity to try to achieve it.…

Leave a Reply

Your email address will not be published.