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NASA’s Noise-Reduction Tech to Make Quieter Airports a Reality

The Landing Gear Noise Reduction technology element addressed airframe noise caused by airflow moving past the landing gear on approach

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Just 11 years after Eisenhower authorized NASA, American astronaut Neil Armstrong walked on the moon. Pixabay
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Aiming to reduce aircraft noise for communities that live near airports, NASA has successfully tested new noise reduction technologies on a series of Acoustic Research Measurement (ARM) flight, and managed to cut airframe noise during landing by more than 70 per cent.

The ARM flights, which concluded in May, at NASA’s Armstrong Flight Research Center in California, tested technology to address airframe noise, or noise that is produced by non-propulsive parts of the aircraft, during landing.

NASA successfully combined several technologies including Landing Gear Noise Reduction, landing gear cavity treatments, and the Adaptive Compliant Trailing Edge flexible wing flap, on various airframe components of a Gulfstream III research aircraft to achieve a greater than 70 per cent reduction in airframe noise.

“This airframe noise reduction produced by NASA technology is definitely momentous, and the best part is that it directly benefits the public,” ARM Project Manager Kevin Weinert, said in a statement.

“We are very confident that with the tested technologies we can substantially reduce total aircraft noise, and that could really make a lot of flights much quieter,” added Mehdi Khorrami, an aerospace scientist at NASA’s Langley Research Center in Virginia.

The Gulfstream III research aircraft flew at an altitude of 350 feet, over an 185-sensor microphone array deployed on the Rogers Dry Lake at Edwards Air Force Base in California.

NASA jet
Representational image. (IANS)

The Landing Gear Noise Reduction technology element addressed airframe noise caused by airflow moving past the landing gear on approach.

Another area of focus was landing gear cavities, also a known cause of airframe noise. These are the regions where the landing gear deploys from the main body of an aircraft, typically leaving a large cavity where airflow can get pulled in, creating noise.

NASA applied two concepts to these sections, including a series of chevrons placed near the front of the cavity with a sound-absorbing foam at the trailing wall, as well as a net that stretched across the opening of the main landing gear cavity.

This altered the airflow and reduced the noise resulting from the interactions between the air, the cavity walls, and its edges, the report said.

Also Read: NASA Seeks Partnership With US Industry to Develop First Gateway Element

To reduce wing flap noise, NASA used an experimental, flexible flap, which investigated the potential for flexible, seamless flaps to increase aerodynamic efficiency.

“While there are obvious potential economic gains for the industry, this benefits the people who live near major airports, and have to deal with the noise of aircraft coming in to land. This could greatly reduce the noise impact on these communities,” Weinert said. (IANS)

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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)