Tuesday June 18, 2019
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The Secret Behind NASA’s Parker Solar Probe

The spacecraft, launched from Cape Canaveral Air Force Station in Florida on August 12, will transmit its first scientific observations in December.

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Why won't NASA's Parker Solar Probe melt?
Why won't NASA's Parker Solar Probe melt?VOA

With NASA launching a historic Parker Solar Probe deeper into the solar atmosphere than any mission before it, a moot question arises: Why won’t it melt?

Inside the solar atmosphere — a region known as the corona — the probe will provide observations of what drives the wide range of particles, energy and heat that course through the region.

The spacecraft will travel through material with temperatures greater than several million degrees Celsius while being bombarded with intense sunlight.

According to the US space agency, 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,” NASA said in a statement.

Parker solar probe
The spacecraft, launched from Cape Canaveral Air Force Station. IANS

While the Parker Solar Probe will travel 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 1,400 degree Celsius.

This is because “in space, the temperature can be thousands of degrees without providing significant heat to a given object or feeling hot. Since space is mostly empty, there are very few particles that can transfer energy to the spacecraft”.

The corona through which the Parker Solar Probe flies, for example, has an extremely high temperature but very low density.

The probe makes use of a heat shield known as the Thermal Protection System, or TPS, which is eight feet in diameter and 4.5 inches thick.

Those few inches of protection mean that just on the other side of the shield, the spacecraft body will sit at a comfortable 30 degrees Celsius.

Parker-Solar-2, NASA
The Parker Solar Probe sits in a clean room at Astrotech Space Operations in Titusville, Fla., after the installation of its heat shield. VOA

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 1,650 degrees Celsius, the TPS can handle any heat the Sun can send its way, keeping almost all instrumentation safe,” said NASA.

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 the chemical element niobium.

NASA
Several other designs on the spacecraft keep Parker Solar Probe sheltered from the heat.Flickr

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.

Also Read: Red-hot Voyage to Sun Will Bring us Closer to our Star

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, aluminium fins to maximise the cooling surface, and pumps to circulate the coolant.

The spacecraft, launched from Cape Canaveral Air Force Station in Florida on August 12, will transmit its first scientific observations in December. (IANS)

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NASA: Sending Back Astronauts to Moon in 2024 Could Cost About $30 Billion

The entire project will be framed as a practice run for a future mission to Mars

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NASA, mars
NASA, which has dubbed its current lunar programme Artemis (after Apollo's twin sister, the Greek goddess of the hunt, the wilderness and the moon), plans to send one male and one female astronaut to the moon in 2024. VOA

Returning astronauts to the moon in 2024 could cost about $30 billion, or roughly the same price tag as the Apollo 11 spaceflight when factoring in inflation, NASA has said.

“For the whole programme, to get a sustainable presence on the moon, we’re looking at between $20 and $30 billion,” NASA Administrator Jim Bridenstine said in a TV interview on Friday, though noting that that figure does not include money already spent on the rocket and space capsule the agency plans to use for the programme, Efe news reported.

The total cost of the Apollo programme that the US launched in 1961 and concluded in 1972 was $25 billion. The climax of that programme came nearly 50 years ago when two astronauts landed on the moon as part of the Apollo 11 mission, which cost $6 billion at the time, equivalent to $30 billion today.

nasa, moon
Then one male astronaut and – for the first time – a female astronaut would set foot on the lunar surface in 2024. Pixabay

NASA, which has dubbed its current lunar programme Artemis (after Apollo’s twin sister, the Greek goddess of the hunt, the wilderness and the moon), plans to send one male and one female astronaut to the moon in 2024.

Bridenstine recalled that the main difference between the Apollo programme and the Artemis program is that the former culminated with brief stays on the moon while the latter will entail a permanent human presence there.

The plan will involve the recruitment of private companies and international partners, the construction of a lunar space station and manned landings at the moon’s south pole within five years.

NASA, moon
That rocket will send into orbit a new spacecraft known as Orion, whose lead contractor is Lockheed Martin. VOA

The entire project will be framed as a practice run for a future mission to Mars. The programme includes an unmanned mission around the moon in 2020 and a manned mission that also will orbit the moon two years later. Then one male astronaut and – for the first time – a female astronaut would set foot on the lunar surface in 2024.

ALSO READ: NASA’s Mars 2020 Rover, Latest Robotic Mission to Explore Ancient Life on Red Planet

The three lunar missions will be delivered into space by the Space Launch System, a rocket being developed by NASA and Boeing that will be the largest ever built once it is fully assembled. That rocket will send into orbit a new spacecraft known as Orion, whose lead contractor is Lockheed Martin.

Besides these missions exclusively handled by NASA, five other launches will be carried out to place in lunar orbit the components for construction of the Gateway mini-space station, which will serve as a staging post for moon landings. Those five missions between 2022 and 2024 will be operated by private companies, according to NASA’s plans. (IANS)