NASA - Orion Ground Test Vehicle Arrives at Kennedy

The Orion Ground Test Vehicle arrived at NASA's Kennedy Space Center Operations & Checkout (O&C) Facility on April 21. 

The vehicle traveled more than 1,800 miles from Lockheed Martin's Waterton Facility near Denver, Colo., where it successfully completed a series of rigorous acoustic, modal and vibration tests that simulated launch and spaceflight environments.

The ground test vehicle will now be used for pathfinding operations at the O&C in preparation for the Orion spaceflight test vehicle's arrival this summer. 

The spaceflight vehicle is currently being fabricated at NASA's Michoud Assembly Facility in New Orleans, La., and is slated for NASA's Exploration Flight Test, or EFT-1, in 2014.

Image Credit: NASA

NASA NPP Runs the Gauntlet of Environmental Testing

The NPP satellite sits surrounded by 144 rock concert speakers. They're stacked in a circle 16 feet high in a testing room at Ball Aerospace in Boulder, Colorado.

As engineers set up for the environmental test, Pink Floyd's song "Money" plays gently in the background.

The music stops. The room clears. Then the sound engineer wearing earplugs and headphones in the control room next door flips a switch.

Slowly, the noise of thousands of pounds of exploding rocket fuel builds louder and louder until it blasts the satellite at a deafening 143.6 decibels -- loud enough to cause serious damage and pain to unprotected ears.

"I was outside the building when they did the full level acoustics," says Glenn Iona, NPP Chief Engineer at NASA Goddard Space Flight Center, Greenbelt, Md. "and I could feel the ground shaking."

The acoustic test is one of a gauntlet of environmental tests a satellite must pass to prove that it can survive launch and life in space. For Large Class Observatory mission NPP, this process took years to plan, 15 months to execute and was fraught with as many engineering challenges as building the satellite itself.

The NPOESS Preparatory Project (NPP) is the prototype for the next generation of Earth-observing satellites that will monitor daily weather and long-term ozone levels and climate change.

NPP's five instruments will continue data collection now done by an aging fleet of satellites. NASA's oldest Earth Observing System (EOS) satellites are more than 10 years old, with instrument designs and technology dating back to the early 1990s.

NPP is the bridge between the original EOS missions and the Joint Polar Satellite System (JPSS). JPSS, previously called the National Polar-orbiting Operational Environmental Satellite System (NPOESS), will be developed by NASA for the National Oceanic and Atmospheric Administration (NOAA).

Testing to evaluate whether a satellite is ready for space occurs at several levels. Some individual parts and each individual instrument from the satellite go through three types of testing: dynamic, electromagnetic compatibility, and thermal vacuum.

Then the parts are integrated onto the main satellite bus, a wedge-shaped block the size of a four-door sedan. The bus has propulsion systems, a flight computer, a data processing computer, data storage and a solar panel wing that powers it all.

Engineers then put the spacecraft and instruments through their paces to get a performance baseline before the whole satellite is run through the suite of environmental tests again.

NASA: ORION (OMPCV) Integration

Preparations are underway to begin integration of the Orion Multi-Purpose Crew Vehicle Launch Abort System (foreground) with the Crew Module (background) for acoustical testing.

The tests will be conducted in the Reverberant Acoustics Laboratory at the Lockheed Martin Waterton facility near Denver, Colorado.

The Orion stack will be exposed to a series of acoustic tests of increasing decibels that simulate the sound pressure levels that the vehicle will encounter during launch.

Image Credit: NASA

ESA: Celebrating 10 years of Artemis - Testing

Testing of ESAs Artemis satellite in the Compact Payload Test Range (CPTR) in ESTECs Test Centre. Artemis (Advanced Relay and Technology Mission Satellite) is planned for launch in 2000 on Japan's H2A vehicle to demonstrate new telecommunications techniques.

The L-band payload will allow 2-way communications between fixed Earth stations and land mobiles (trucks, trains and cars) in Europe and North Africa.

Two payloads will provide communications directly between satellites, receiving data from low Earth-orbiting satellites and relaying them to Europ.

Credits: ESA

Tibetan singing bowls

We present the results of an experimental investigation of the acoustics and fluid dynamics of Tibetan singing bowls.

The Acoustic effect of Tibetan Singing Bowls on Water

Their acoustic behaviour is rationalised in terms of the related dynamics of standing bells and wine glasses.

Striking or rubbing a fluid-filled bowl excites wall vibrations, and concomitant waves at the fluid surface.

Acoustic excitation of the bowl's natural vibrational modes allows for a controlled study in which the evolution of the surface waves with increasing forcing amplitude is detailed.

Particular attention is given to rationalising the observed criteria for the onset of edge-induced Faraday waves and droplet generation via surface fracture. Our study indicates that drops may be levitated on the fluid surface, induced to bounce on or skip across the vibrating fluid surface.

Watch the study video here on the BBC website:

Read the full report here: http://iopscience.iop.org/

A YouTube Video of Tibetan Singing Bowls Music

Acoustic cloak hides underwater objects from sonar

You’ve probably heard of invisibility cloaks that can hide tiny objects, even those visible to the naked eye. Now, researchers have used the same types of metamaterials to create an acoustic cloak, a technology that renders underwater objects invisible to sonar and other ultrasound waves.

A metamaterial is a class of artificial materials that have enhanced properties as a result of their structure.

Credit: L. Brian Stauffer

“We are not talking about science fiction. We are talking about controlling sound waves by bending and twisting them in a designer space,” said Nicholas Fang, a mechanical science and engineering professor at the University of Illinois at Urbana-Champaign and leader of the project.

“This is certainly not some trick Harry Potter is playing with,” he said in a university release.

Fang and his team of researchers designed a two-dimensional cylindrical cloak made of 16 concentric rings of acoustic circuits structured to guide sound waves. Each ring has a different index of refraction, meaning that sound waves vary their speed from the outer rings to the inner ones.

The speed is slower at the outer rings so that’s where sound waves propagate since greater energy is required for them to move to the inner rings. The specially structured acoustic circuits bend the sound waves to wrap them around the outer layers of the cloak.

“Basically what you are looking at is an array of cavities that are connected by channels. The sound is going to propagate inside those channels, and the cavities are designed to slow the waves down,” Fang said. “As you go further inside the rings, sound waves gain faster and faster speed.”

Tests revealed that the acoustic cloak can effectively bend the ultrasound waves around the hidden object.

The researchers submerged a steel cylinder in a tank with an ultrasound source on one side and a sensor array on the other, then placed the cylinder inside the cloak and watched it disappear from their sonar. They also tested other various objects and found the same results.

“The structure of what you’re trying to hide doesn’t matter,” Fang said. “The effect is similar. After we placed the cloaked structure around the object we wanted to hide, the scattering or shadow effect was greatly reduced.”

It is also capable of hiding an object from a broad range of sound waves from 40 to 80 KHz and potentially tens of megahertz with modifications.

Acoustic Tests On New Glonass-K Satellite Completed

Acoustic tests on a new generation Glonass-K navigation satellite have been completed at a plant in southern Russia.

"These types of experimental tests were carried out to confirm the resilience of the Glonass-K satellite to the acoustic pressure which will be applied on it when it is orbited," a statement by the plant said. "The tests were successful."

The Glonass-K, a new generation satellite navigation system, is set for launch later this year.

The satellite is operable for 10 years.

Glonass - the Global Navigation Satellite System - is the Russian equivalent of the U.S. Global Positioning System
, or GPS, and is designed for both military and civilian use. Both systems allow users to determine their positions to within a few meters.

Russia currently has a total of 22 Glonass-M satellites in orbit, but only 16 of them are operational. The system requires 18 operational satellites for continuous navigation services covering the entire territory of Russia and at least 24 satellites to provide navigation services worldwide.