Why Parker Solar Probe Won’T Melt?

Why Parker Solar Probe Won
So, why won’t it melt? – Parker Solar Probe has been the extreme conditions and temperature variances for the mission. The key lies in its custom warmth shield and a self-ruling system that shields the mission from the Sun’s extreme light outflow, yet allows the coronal material to “touch” the spacecraft.

  1. In space, the temperature can be a great many degrees without giving critical heat to a given protest or feeling hot.
  2. Why? Temperature measures how quick particles are moving, while heat measures the aggregate sum of vitality that they exchange.
  3. In the Astrotech processing facility in Titusville, Florida, near NASA’s Kennedy Space Center, on Tuesday, June 5, 2018, technicians and engineers perform light bar testing on NASA’s Parker Solar Probe.

The Parker Solar Probe will launch on a United Launch Alliance Delta IV Heavy rocket from Space Launch Complex 37 at Cape Canaveral Air Force Station in Florida no earlier than Aug.4, 2018. The mission will perform the closest-ever observations of a star when it travels through the Sun’s atmosphere, called the corona.

The probe will rely on measurements and imaging to revolutionize our understanding of the corona and the Sun-Earth connection. Particles might move quick (high temperature), yet in the event that there are not very many of them, they won’t exchange much energy (low heat). Since space is mostly empty, there are not very many particles that can exchange energy to the shuttle.

The corona through which Parker Solar Probe flies, for example, has an extremely high temperature but very low density. Think of the difference between putting your hand in a hot oven versus putting it in a pot of boiling water (don’t try this at home!) — in the oven, your hand can withstand significantly hotter temperatures for longer than in the water where it has to interact with many more particles.

Similarly, compared to the visible surface of the Sun, the corona is less dense, so the spacecraft interacts with fewer hot particles and doesn’t receive as much heat. That means that while Parker Solar Probe will be traveling through space with temperatures of several million degrees, the surface of the heat shield that faces the Sun will only get heated to about 2,500 degrees Fahrenheit (about 1,400 degrees Celsius).

Parker Solar Probe’s heat shield is made of two panels of superheated carbon-carbon composite sandwiching a lightweight 4.5-inch-thick carbon foam core. To reflect as much of the Sun’s energy away from the spacecraft as possible, the Sun-facing side of the heat shield is also sprayed with a specially formulated white coating.Credits: NASA/Johns Hopkins APL/Ed Whitman Parker solar probe makes use of a heat shield known as the Thermal Protection System, or TPS, which is 8 feet (2.4 meters) in diameter and 4.5 inches (about 115 mm) thick.

  • Those few inches of protection mean that just on the other side of the shield, the spacecraft body will sit at a comfortable 85 F (30 C).
  • The TPS is composed of a carbon composite froth sandwiched between two carbon plates.
  • This lightweight protection will be joined by a completing dash of white earthenware paint on the sun-facing plate, to reflect however much heat as could be expected.

Tried to withstand up to 3,000 F (1,650 C), the TPS can deal with any warmth the Sun can send its direction, protecting all instrumentation. The probe also consists of Solar Probe Cup also known as Faraday cup. It mimics as a sensor to quantify the ion and electron fluxes and flow angles from the solar wind.

  • The cup itself is made from sheets of Titanium-Zirconium-Molybdenum, an alloy of molybdenum, with a melting point of about 4,260 F (2,349 C).
  • The chips that produce an electric field for the Solar Probe Cup are made from tungsten, a metal with the highest known melting point of 6,192 F (3,422 C).
  • Normally lasers are used to etch the gridlines in these chips — however, due to the high melting point acid had to be used instead.

When it comes to electronic wiring, scientists used sapphire crystal tubes to suspend the wiring and made the wires from niobium. To make sure the instrument was ready for the harsh environment, the researchers needed to mimic the Sun’s intense heat radiation in a lab.

  • To create a test-worthy level of heat, the researchers used a particle accelerator and IMAX projectors — jury-rigged to increase their temperature.
  • The projectors mimicked the heat of the Sun, while the particle accelerator exposed the cup to radiation to make sure the cup could measure the accelerated particles under the intense conditions.

To be absolutely sure the Solar Probe Cup would withstand the harsh environment, the Odeillo Solar Furnace — which concentrates the heat of the Sun through 10,000 adjustable mirrors — was used to test the cup against the intense solar emission. Justin Kasper, principal investigator for the SWEAP instruments at the University of Michigan in Ann Arbor said, “The Solar Probe Cup passed its tests with flying colors — indeed, it continued to perform better and give clearer results the longer it was exposed to the test environments.

  1. We think the radiation removed any potential contamination.
  2. It basically cleaned itself.” There are several other approaches that solar probe used to shelter from the heat.
  3. For example, the solar arrays that retract behind the heat shield’s shadow, leaving only a small segment exposed to the Sun’s intense rays.

The solar arrays have a surprisingly simple cooling system: a heated tank that keeps the coolant from freezing during launch, two radiators that will keep the coolant from freezing, aluminum fins to maximize the cooling surface, and pumps to circulate the coolant.

The cooling system is powerful enough to cool an average sized living room, and will keep the solar arrays and instrumentation cool and functioning while in the heat of the Sun. The coolant used for the system? About a gallon (3.7 liters) of deionized water. While plenty of chemical coolants exist, the range of temperatures the spacecraft will be exposed to varies between 50 F (10 C) and 257 F (125 C).

Very few liquids can handle those ranges like water. To keep the water from boiling at the higher end of the temperatures, it will be pressurized so the boiling point is over 257 F (125 C). In this way, the probe is designed to autonomously keep itself safe and on track to the Sun.

Several sensors, about half the size of a cell phone, are attached to the body of the spacecraft along the edge of the shadow from the heat shield. If any of these sensors detect sunlight, they alert the central computer and the spacecraft can correct its position to keep the sensors, and the rest of the instruments, safely protected.

This all has to happen without any human intervention, so the central computer software has been programmed and extensively tested to make sure all corrections can be made on the fly. : Traveling to the Sun: Why won’t Parker solar probe melt?
Why didn’t the Probe Melt? – Parker Solar Probe is built to resist the mission’s extreme climate conditions and wide temperature swings. With its unique heat shield and an autonomous mechanism that protects the probe yet allows coronal material to “touch” the spacecraft is the most critical feature. Similarly, the corona is less dense than the visible surface of the Sun, so the spacecraft encounters fewer hot particles and does not get as much heat as it would on the visible surface. As a result, the heat shield facing the Sun on Parker Solar Probe will only be heated to roughly 2,500 F (1,400 C) while it travels through the corona atmosphere with temperatures of several million degrees.

Why does the Parker probe not melt?

How did the Parker Solar Probe survive the Sun’s heat? – The Parker Solar Probe is the closest spacecraft to the Sun, and it is able to survive the extreme temperatures due to a thermal shield that is made of carbon-composite material, withstanding up to 2,500-degrees fahrenheit or 1,377-degrees celsius.

This shield cuts into the Sun’s heat similar to a racing car cutting into the air. A racing car cutting through the air makes it easier for the one behind it to accelerate as the wind resistance is lowered. Similarly, the thermal shield pushes the heat away, making a manageable temperature for the probe and its instruments.

SEE ALSO: 2021 in space — First space tourists, leaky toilet, film shooting, and more NASA to launch four Earth science missions in 2022 — All you need to know

Why does NASA probe inside the Sun’s atmosphere hasn’t melted?

Parker Solar Probe has been designed to withstand the extreme conditions and temperature fluctuations for the mission. The key lies in its custom heat shield and an autonomous system that helps protect the mission from the Sun’s intense light emission, but does allow the coronal material to ‘touch’ the spacecraft.

How can the Parker Solar Probe withstand the heat of the Sun?

To perform these unprecedented investigations, the spacecraft and instruments are protected from the Sun’s heat by a 4.5-inch-thick (11.43 cm) carbon-composite shield, which needs to withstand temperatures outside the spacecraft that reach nearly 2,500 F (1,377 C).

Is there anything the sun can’t melt?

Can anything withstand the immense heat of the Sun? by · 13/04/2015 The Sun is surrounded by a layer of plasma which extends millions of miles into space, in some places reaching up to 3 million degrees Celsius (5.4 million degrees Fahrenheit).

  • There are no known materials that can exist as solids, liquids or gases at such extreme temperatures.
  • Protons, neutrons and electrons can withstand this heat as they are virtually indestructible, however they can only exist as plasma.
  • If you could somehow get past the corona to the surface of the Sun, where it is ‘only’ 5,500 degrees Celsius (9,900 degrees Fahrenheit), some liquids could exist.
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  1. Plus, take a look at:

: Can anything withstand the immense heat of the Sun?

How do satellites not melt?

WHY SATELLITES DON’T MELT – The key to understanding why satellites do not melt or burn up is the difference between temperature and heat. Temperature measures the thermal energy of particles, but as the air in the thermosphere is thin – as if it were a vacuum – there are not enough particles to transfer energy, causing low heat ( here ), ( here ).

  1. As NASA explains it, if a human were to be in the thermosphere, they “would be very cold because there aren’t enough gas molecules to transfer the heat” into the body ( here ).
  2. Thomas Murphy, a PhD student at the MIT STAR Lab who is involved in building and operating two small satellites in space ( starlab.mit.edu/people ), told Reuters that a satellite would need to encounter a substantial amount of high-temperature gas molecules in the thermosphere, “but the fact that there are so incredibly few molecules up there means melting isn’t a concern.” Murphy compared a satellite hitting high-temperature molecules to a bullet train hitting a fly.

“Even though they can go up to 200 mph, the impact against the fly doesn’t do anything to the train, because the fly is just too tiny to matter,” Murphy said. “Now, if somehow there was a giant mountain of flies in front of the train, that would be a different story, but if it just hits single flies one by one, the high speed doesn’t put the train in jeopardy.” Most satellites and other spacecrafts that are built for re-entry to Earth include a heat shield known as a Thermal Protection System (TPS), which is meant to withstand the incredible heat as they descend from space ( here ), made from ablative materials.

Most heat shields, including the one for the Orion spacecraft, are designed with a capsule shape ( here ). A satellite or spacecraft coming back to Earth will be in an environment that’s “basically in the middle of a giant fireball,” Murphy said. To ensure the spacecraft and astronauts, if any, survive, it would require a heat shield for safety.

Other satellites do not need to survive re-entry, and do not require a heat shield to withstand the temperatures of space. “The heat shield is only doing its job as coming back to Earth and is not related to anything involving the thermosphere,” Murphy said.

How did the Parker probe survive?

In Depth: Parker Solar Probe – NASA’s Parker Solar Probe is diving into the Sun’s atmosphere, facing brutal heat and radiation, on a mission to give humanity its first-ever sampling of a star’s atmosphere. On Dec.14, 2021, NASA announced that Parker had flown through the Sun’s upper atmosphere – the corona – and sampled particles and magnetic fields there.

This marked the first time in history, a spacecraft had touched the Sun. Parker Solar Probe is designed to swoop within about 4 million miles (6.5 million kilometers) of the Sun’s surface to trace the flow of energy, to study the heating of the solar corona, and to explore what accelerates the solar wind.

During its journey, the mission will provide answers to long-standing questions that have puzzled scientists for more than 60 years: Why is the corona much hotter than the Sun’s surface (the photosphere)? How does the solar wind accelerate? What are the sources of high-energy solar particles? We live in the Sun’s atmosphere and this mission will help scientists better understand the Sun’s impact on Earth.

  1. Data from Parker will be key to understanding and, perhaps, forecasting space weather.
  2. Space weather can change the orbits of satellites, shorten their lifetimes, or interfere with onboard electronics.
  3. Parker can survive the Sun’s harsh conditions because cutting-edge thermal engineering advances protect the spacecraft during its dangerous journey.

The probe has four instrument suites designed to study magnetic fields, plasma, and energetic particles, and image the solar wind. The mission is named for Dr. Eugene N. Parker, who pioneered our modern understanding of the Sun.

How long will the Parker Solar Probe last?

Parker Solar Probe

Model of the Parker Solar Probe.
Names Solar Probe (before 2002) Solar Probe Plus (2010–2017) Parker Solar Probe (since 2017)
Mission type Heliophysics
Operator NASA / Applied Physics Laboratory
COSPAR ID 2018-065A
SATCAT no. 43592
Website parkersolarprobe,jhuapl,edu
Mission duration 7 years (planned) Elapsed: 4 years, 2 months and 18 days
Spacecraft properties
Manufacturer Applied Physics Laboratory
Launch mass 685 kg (1,510 lb)
Dry mass 555 kg (1,224 lb)
Payload mass 50 kg (110 lb)
Dimensions 1.0 m × 3.0 m × 2.3 m (3.3 ft × 9.8 ft × 7.5 ft)
Power 343 W (at closest approach)
Start of mission
Launch date 12 August 2018, 07:31 UTC
Rocket Delta IV Heavy / Star-48BV
Launch site Cape Canaveral, SLC-37
Contractor United Launch Alliance
Orbital parameters
Reference system Heliocentric orbit
Semi-major axis 0.388 AU (58.0 million km; 36.1 million mi)
Perihelion altitude 0.046 AU (6.9 million km; 4.3 million mi; 9.86 R ☉ )
Aphelion altitude 0.73 AU (109 million km; 68 million mi)
Inclination 3.4°
Period 88 days
Sun
Transponders
Band K a -band X-band
show Instruments

/td> The official insignia for the mission.

The Parker Solar Probe ( PSP ; previously Solar Probe, Solar Probe Plus or Solar Probe+ ) is a NASA space probe launched in 2018 with the mission of making observations of the outer corona of the Sun, It will approach to within 9.86 solar radii (6.9 million km or 4.3 million miles) from the center of the Sun, and by 2025 will travel, at closest approach, as fast as 690,000 km/h (430,000 mph), or 0.064% the speed of light,

It is the fastest object ever built. The project was announced in the fiscal 2009 budget year. The cost of the project is US$1.5 billion. Johns Hopkins University Applied Physics Laboratory designed and built the spacecraft, which was launched on 12 August 2018. It became the first NASA spacecraft named after a living person, honoring nonagenarian physicist Eugene Newman Parker, professor emeritus at the University of Chicago,

A memory card containing the names of over 1.1 million people was mounted on a plaque and installed below the spacecraft’s high-gain antenna on 18 May 2018. The card also contains photos of Parker and a copy of his 1958 scientific paper predicting important aspects of solar physics,

  1. On 29 October 2018, at about 18:04 UTC, the spacecraft became the closest ever artificial object to the Sun.
  2. The previous record, 42.73 million kilometres (26.55 million miles) from the Sun’s surface, was set by the Helios 2 spacecraft in April 1976.
  3. As of its perihelion 21 November 2021, the Parker Solar Probe’s closest approach is 8.5 million kilometres (5.3 million miles).

This will be surpassed after each of the two remaining flybys of Venus,

Which metal is used in Parker Solar Probe?

FIELDS measures the electric field around the spacecraft with five antennas, four of which stick out beyond the spacecraft’s heat shield and into the sunlight, where they experience temperatures of 2,500 F. The 2-meter-long antennas are made of a niobium alloy, which can withstand extreme temperatures.

How does the Parker Solar Probe protect itself from the Sun?

Parker Solar Probe has been designed to withstand the extreme conditions and temperature fluctuations for the mission. The key lies in its custom heat shield and an autonomous system that helps protect the mission from the Sun’s intense light emission, but does allow the coronal material to ‘touch’ the spacecraft.

What is the Solar Probe Cup and how does it work?

Traveling to the sun: Why won’t Parker Solar Probe melt? Illustration of Parker Solar Probe circling the Sun. Credit: NASA/JHUAPL This summer, NASA’s Parker Solar Probe will launch to travel closer to the Sun, deeper into the solar atmosphere, than any mission before it. If Earth was at one end of a yard-stick and the Sun on the other, Parker Solar Probe will make it to within four inches of the solar surface.

Inside that part of the solar atmosphere, a region known as the corona, Parker Solar Probe will provide unprecedented observations of what drives the wide range of particles, energy and that course through the region—flinging particles outward into the solar system and far past Neptune. Inside the corona, it’s also, of course, unimaginably hot.

The spacecraft will travel through material with temperatures greater than a million degrees Fahrenheit while being bombarded with intense sun light. So, why won’t it melt? Parker Solar Probe has been designed to withstand the extreme conditions and temperature fluctuations for the mission.

The key lies in its custom heat shield and an autonomous system that helps protect the mission from the Sun’s intense light emission, but does allow the coronal material to “touch” the spacecraft. The Science Behind Why It Won’t Melt One key to understanding what keeps the spacecraft and its instruments safe, is understanding the concept of heat versus temperature.

Counterintuitively, high temperatures do not always translate to actually heating another object. NASA’s Parker Solar Probe is heading to the Sun. Why won’t the spacecraft melt? Thermal Protection System Engineer Betsy Congdon (Johns Hopkins APL) outlines why Parker can take the heat.

Credit: NASA’s Goddard Space Flight Center In space, the temperature can be thousands of degrees without providing significant heat to a given object or feeling hot. Why? Temperature measures how fast particles are moving, whereas heat measures the total amount of energy that they transfer. Particles may be moving fast (high temperature), but if there are very few of them, they won’t transfer much energy (low heat).

Since space is mostly empty, there are very few particles that can transfer energy to the spacecraft. The corona through which Parker Solar Probe flies, for example, has an extremely high temperature but very low density. Think of the difference between putting your hand in a hot oven versus putting it in a pot of boiling water (don’t try this at home!)—in the oven, your hand can withstand significantly hotter temperatures for longer than in the water where it has to interact with many more particles.

Similarly, compared to the visible surface of the Sun, the corona is less dense, so the spacecraft interacts with fewer hot particles and doesn’t receive as much heat. That means that while Parker Solar Probe will be traveling through a space with temperatures of several million degrees, the surface of the heat shield that faces the Sun will only get heated to about 2,500 degrees Fahrenheit (about 1,400 degrees Celsius).

The Shield That Protects It Of course, thousands of degrees Fahrenheit is still fantastically hot. (For comparison, lava from volcano eruptions can be anywhere between 1,300 and 2,200 F (700 and 1,200 C) And to withstand that heat, Parker Solar Probe makes use of a heat shield known as the Thermal Protection System, or TPS, which is 8 feet (2.4 meters) in diameter and 4.5 inches (about 115 mm) thick.

  1. Those few inches of protection mean that just on the other side of the shield, the spacecraft body will sit at a comfortable 85 F (30 C).
  2. The TPS was designed by the Johns Hopkins Applied Physics Laboratory, and was built at Carbon-Carbon Advanced Technologies, using a carbon composite foam sandwiched between two carbon plates.

This lightweight insulation will be accompanied by a finishing touch of white ceramic paint on the sun-facing plate, to reflect as much heat as possible. Tested to withstand up to 3,000 F (1,650 C), the TPS can handle any heat the Sun can send its way, keeping almost all instrumentation safe.

  1. Betsy Congdon of Johns Hopkins Applied Physics Lab is the lead thermal engineer on the heat shield that NASA’s Parker Solar Probe will use to protect itself against the Sun.
  2. The shield is so robust, Congdon can use a blowtorch on one side and the other side remains cool enough to touch.
  3. Credit: NASA’s Goddard Space Flight Center The Cup that Measures the Wind But not all of the Solar Parker Probe instruments will be behind the TPS.

Poking out over the heat shield, the Solar Probe Cup is one of two instruments on Parker Solar Probe that will not be protected by the heat shield. This instrument is what’s known as a Faraday cup, a sensor designed to measure the ion and electron fluxes and flow angles from the solar wind.

  • Due to the intensity of the solar atmosphere, unique technologies had to be engineered to make sure that not only can the instrument survive, but also the electronics aboard can send back accurate readings.
  • The cup itself is made from sheets of Titanium-Zirconium-Molybdenum, an alloy of molybdenum, with a melting point of about 4,260 F (2,349 C).

The chips that produce an electric field for the Solar Probe Cup are made from tungsten, a metal with the highest known melting point of 6,192 F (3,422 C). Normally lasers are used to etch the gridlines in these chips—however due to the high melting point acid had to be used instead.

  • Another challenge came in the form of the electronic wiring—most cables would melt from exposure to heat radiation at such close proximity to the Sun.
  • To solve this problem, the team grew sapphire crystal tubes to suspend the wiring, and made the wires from niobium.
  • To make sure the instrument was ready for the harsh environment, the researchers needed to mimic the Sun’s intense heat radiation in a lab.

To create a test-worthy level of heat, the researchers used a particle accelerator and IMAX projectors—jury-rigged to increase their temperature. The projectors mimicked the heat of the Sun, while the particle accelerator exposed the cup to radiation to make sure the cup could measure the accelerated particles under the intense conditions. Parker Solar Probe’s heat shield is made of two panels of superheated carbon-carbon composite sandwiching a lightweight 4.5-inch-thick carbon foam core. To reflect as much of the Sun’s energy away from the spacecraft as possible, the Sun-facing side of the heat shield is also sprayed with a specially formulated white coating.

Credit: NASA/Johns Hopkins APL/Ed Whitman The Solar Probe Cup passed its tests with flying colors—indeed, it continued to perform better and give clearer results the longer it was exposed to the test environments. “We think the radiation removed any potential contamination,” Justin Kasper, principal investigator for the SWEAP instruments at the University of Michigan in Ann Arbor, said.

“It basically cleaned itself.” The Spacecraft That Keeps its Cool Several other designs on the spacecraft keep Parker Solar Probe sheltered from the heat. Without protection, the solar panels—which use energy from the very star being studied to power the spacecraft—can overheat.

At each approach to the Sun, the solar arrays retract behind the heat shield’s shadow, leaving only a small segment exposed to the Sun’s intense rays. But that close to the Sun, even more protection is needed. The solar arrays have a surprisingly simple cooling system: a heated tank that keeps the coolant from freezing during launch, two radiators that will keep the coolant from freezing, aluminum fins to maximize the cooling surface, and pumps to circulate the coolant.

The cooling system is powerful enough to cool an average sized living room, and will keep the solar arrays and instrumentation cool and functioning while in the heat of the Sun. The coolant used for the system? About a gallon (3.7 liters) of deionized water.

While plenty of chemical coolants exist, the range of temperatures the spacecraft will be exposed to varies between 50 F (10 C) and 257 F (125 C). Very few liquids can handle those ranges like water. To keep the water from boiling at the higher end of the temperatures, it will be pressurized so the boiling point is over 257 F (125 C).

Another issue with protecting any spacecraft is figuring out how to communicate with it. Parker Solar Probe will largely be alone on its journey. It takes light eight minutes to reach Earth—meaning if engineers had to control the spacecraft from Earth, by the time something went wrong it would be too late to correct it. In the Astrotech processing facility in Titusville, Florida, near NASA’s Kennedy Space Center, on Tuesday, June 5, 2018, technicians and engineers perform light bar testing on NASA’s Parker Solar Probe. The spacecraft will launch on a United Launch Alliance Delta IV Heavy rocket from Space Launch Complex 37 at Cape Canaveral Air Force Station in Florida.

The mission will perform the closest-ever observations of a star when it travels through the Sun’s atmosphere, called the corona. The probe will rely on measurements and imaging to revolutionize our understanding of the corona and the Sun-Earth connection. Credit: NASA/Glenn Benson So, the spacecraft is designed to autonomously keep itself safe and on track to the Sun.

Several sensors, about half the size of a cell phone, are attached to the body of the spacecraft along the edge of the shadow from the heat shield. If any of these sensors detect sunlight, they alert the central computer and the spacecraft can correct its position to keep the sensors, and the rest of the instruments, safely protected.

  • This all has to happen without any human intervention, so the central computer software has been programmed and extensively tested to make sure all corrections can be made on the fly.
  • Launching toward the Sun After launch, Parker Solar Probe will detect the position of the Sun, align the thermal protection shield to face it and continue its journey for the next three months, embracing the heat of the Sun and protecting itself from the cold vacuum of space.

Over the course of seven years of planned mission duration, the will make 24 orbits of our star. On each close approach to the Sun it will sample the solar wind, study the Sun’s corona, and provide unprecedentedly close up observations from around our star—and armed with its slew of innovative technologies, we know it will keep its cool the whole time.

  1. Citation : Traveling to the sun: Why won’t Parker Solar Probe melt? (2018, July 19) retrieved 2 November 2022 from https://phys.org/news/2018-07-sun-wont-parker-solar-probe.html This document is subject to copyright.
  2. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission.

The content is provided for information purposes only. : Traveling to the sun: Why won’t Parker Solar Probe melt?

How do solar panels protect the solar panels from the Sun?

Traveling to the sun: Why won’t Parker Solar Probe melt? Illustration of Parker Solar Probe circling the Sun. Credit: NASA/JHUAPL This summer, NASA’s Parker Solar Probe will launch to travel closer to the Sun, deeper into the solar atmosphere, than any mission before it. If Earth was at one end of a yard-stick and the Sun on the other, Parker Solar Probe will make it to within four inches of the solar surface.

  1. Inside that part of the solar atmosphere, a region known as the corona, Parker Solar Probe will provide unprecedented observations of what drives the wide range of particles, energy and that course through the region—flinging particles outward into the solar system and far past Neptune.
  2. Inside the corona, it’s also, of course, unimaginably hot.

The spacecraft will travel through material with temperatures greater than a million degrees Fahrenheit while being bombarded with intense sun light. So, why won’t it melt? Parker Solar Probe has been designed to withstand the extreme conditions and temperature fluctuations for the mission.

  • The key lies in its custom heat shield and an autonomous system that helps protect the mission from the Sun’s intense light emission, but does allow the coronal material to “touch” the spacecraft.
  • The Science Behind Why It Won’t Melt One key to understanding what keeps the spacecraft and its instruments safe, is understanding the concept of heat versus temperature.

Counterintuitively, high temperatures do not always translate to actually heating another object. NASA’s Parker Solar Probe is heading to the Sun. Why won’t the spacecraft melt? Thermal Protection System Engineer Betsy Congdon (Johns Hopkins APL) outlines why Parker can take the heat.

  1. Credit: NASA’s Goddard Space Flight Center In space, the temperature can be thousands of degrees without providing significant heat to a given object or feeling hot.
  2. Why? Temperature measures how fast particles are moving, whereas heat measures the total amount of energy that they transfer.
  3. Particles may be moving fast (high temperature), but if there are very few of them, they won’t transfer much energy (low heat).

Since space is mostly empty, there are very few particles that can transfer energy to the spacecraft. The corona through which Parker Solar Probe flies, for example, has an extremely high temperature but very low density. Think of the difference between putting your hand in a hot oven versus putting it in a pot of boiling water (don’t try this at home!)—in the oven, your hand can withstand significantly hotter temperatures for longer than in the water where it has to interact with many more particles.

  • Similarly, compared to the visible surface of the Sun, the corona is less dense, so the spacecraft interacts with fewer hot particles and doesn’t receive as much heat.
  • That means that while Parker Solar Probe will be traveling through a space with temperatures of several million degrees, the surface of the heat shield that faces the Sun will only get heated to about 2,500 degrees Fahrenheit (about 1,400 degrees Celsius).

The Shield That Protects It Of course, thousands of degrees Fahrenheit is still fantastically hot. (For comparison, lava from volcano eruptions can be anywhere between 1,300 and 2,200 F (700 and 1,200 C) And to withstand that heat, Parker Solar Probe makes use of a heat shield known as the Thermal Protection System, or TPS, which is 8 feet (2.4 meters) in diameter and 4.5 inches (about 115 mm) thick.

Those few inches of protection mean that just on the other side of the shield, the spacecraft body will sit at a comfortable 85 F (30 C). The TPS was designed by the Johns Hopkins Applied Physics Laboratory, and was built at Carbon-Carbon Advanced Technologies, using a carbon composite foam sandwiched between two carbon plates.

This lightweight insulation will be accompanied by a finishing touch of white ceramic paint on the sun-facing plate, to reflect as much heat as possible. Tested to withstand up to 3,000 F (1,650 C), the TPS can handle any heat the Sun can send its way, keeping almost all instrumentation safe.

  1. Betsy Congdon of Johns Hopkins Applied Physics Lab is the lead thermal engineer on the heat shield that NASA’s Parker Solar Probe will use to protect itself against the Sun.
  2. The shield is so robust, Congdon can use a blowtorch on one side and the other side remains cool enough to touch.
  3. Credit: NASA’s Goddard Space Flight Center The Cup that Measures the Wind But not all of the Solar Parker Probe instruments will be behind the TPS.

Poking out over the heat shield, the Solar Probe Cup is one of two instruments on Parker Solar Probe that will not be protected by the heat shield. This instrument is what’s known as a Faraday cup, a sensor designed to measure the ion and electron fluxes and flow angles from the solar wind.

Due to the intensity of the solar atmosphere, unique technologies had to be engineered to make sure that not only can the instrument survive, but also the electronics aboard can send back accurate readings. The cup itself is made from sheets of Titanium-Zirconium-Molybdenum, an alloy of molybdenum, with a melting point of about 4,260 F (2,349 C).

The chips that produce an electric field for the Solar Probe Cup are made from tungsten, a metal with the highest known melting point of 6,192 F (3,422 C). Normally lasers are used to etch the gridlines in these chips—however due to the high melting point acid had to be used instead.

Another challenge came in the form of the electronic wiring—most cables would melt from exposure to heat radiation at such close proximity to the Sun. To solve this problem, the team grew sapphire crystal tubes to suspend the wiring, and made the wires from niobium. To make sure the instrument was ready for the harsh environment, the researchers needed to mimic the Sun’s intense heat radiation in a lab.

To create a test-worthy level of heat, the researchers used a particle accelerator and IMAX projectors—jury-rigged to increase their temperature. The projectors mimicked the heat of the Sun, while the particle accelerator exposed the cup to radiation to make sure the cup could measure the accelerated particles under the intense conditions. Parker Solar Probe’s heat shield is made of two panels of superheated carbon-carbon composite sandwiching a lightweight 4.5-inch-thick carbon foam core. To reflect as much of the Sun’s energy away from the spacecraft as possible, the Sun-facing side of the heat shield is also sprayed with a specially formulated white coating.

  1. Credit: NASA/Johns Hopkins APL/Ed Whitman The Solar Probe Cup passed its tests with flying colors—indeed, it continued to perform better and give clearer results the longer it was exposed to the test environments.
  2. We think the radiation removed any potential contamination,” Justin Kasper, principal investigator for the SWEAP instruments at the University of Michigan in Ann Arbor, said.

“It basically cleaned itself.” The Spacecraft That Keeps its Cool Several other designs on the spacecraft keep Parker Solar Probe sheltered from the heat. Without protection, the solar panels—which use energy from the very star being studied to power the spacecraft—can overheat.

At each approach to the Sun, the solar arrays retract behind the heat shield’s shadow, leaving only a small segment exposed to the Sun’s intense rays. But that close to the Sun, even more protection is needed. The solar arrays have a surprisingly simple cooling system: a heated tank that keeps the coolant from freezing during launch, two radiators that will keep the coolant from freezing, aluminum fins to maximize the cooling surface, and pumps to circulate the coolant.

The cooling system is powerful enough to cool an average sized living room, and will keep the solar arrays and instrumentation cool and functioning while in the heat of the Sun. The coolant used for the system? About a gallon (3.7 liters) of deionized water.

While plenty of chemical coolants exist, the range of temperatures the spacecraft will be exposed to varies between 50 F (10 C) and 257 F (125 C). Very few liquids can handle those ranges like water. To keep the water from boiling at the higher end of the temperatures, it will be pressurized so the boiling point is over 257 F (125 C).

Another issue with protecting any spacecraft is figuring out how to communicate with it. Parker Solar Probe will largely be alone on its journey. It takes light eight minutes to reach Earth—meaning if engineers had to control the spacecraft from Earth, by the time something went wrong it would be too late to correct it. In the Astrotech processing facility in Titusville, Florida, near NASA’s Kennedy Space Center, on Tuesday, June 5, 2018, technicians and engineers perform light bar testing on NASA’s Parker Solar Probe. The spacecraft will launch on a United Launch Alliance Delta IV Heavy rocket from Space Launch Complex 37 at Cape Canaveral Air Force Station in Florida.

The mission will perform the closest-ever observations of a star when it travels through the Sun’s atmosphere, called the corona. The probe will rely on measurements and imaging to revolutionize our understanding of the corona and the Sun-Earth connection. Credit: NASA/Glenn Benson So, the spacecraft is designed to autonomously keep itself safe and on track to the Sun.

Several sensors, about half the size of a cell phone, are attached to the body of the spacecraft along the edge of the shadow from the heat shield. If any of these sensors detect sunlight, they alert the central computer and the spacecraft can correct its position to keep the sensors, and the rest of the instruments, safely protected.

  • This all has to happen without any human intervention, so the central computer software has been programmed and extensively tested to make sure all corrections can be made on the fly.
  • Launching toward the Sun After launch, Parker Solar Probe will detect the position of the Sun, align the thermal protection shield to face it and continue its journey for the next three months, embracing the heat of the Sun and protecting itself from the cold vacuum of space.

Over the course of seven years of planned mission duration, the will make 24 orbits of our star. On each close approach to the Sun it will sample the solar wind, study the Sun’s corona, and provide unprecedentedly close up observations from around our star—and armed with its slew of innovative technologies, we know it will keep its cool the whole time.

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