Many thanks to SWLing Post contributor, Dave (K4SV), who shares this video courtesy of NASA Goddard:
The Sun is stirring from its latest slumber. As sunspots and flares, signs of a new solar cycle, bubble from the Sun’s surface, scientists are anticipating a flurry of solar activity over the next few years. Roughly every 11 years, at the height of this cycle, the Sun’s magnetic poles flip — on Earth, that’d be like the North and South Poles’ swapping places every decade — and the Sun transitions from sluggish to active and stormy. At its quietest, the Sun is at solar minimum; during solar maximum, the Sun blazes with bright flares and solar eruptions. In this video, view the Sun’s disk from our space telescopes as it transitions from minimum to maximum in the solar cycle.
Space Communications and Navigation (SCAN) Testbed
The SCAN Testbed, formerly known as Communications, Navigation, and Networking reConfigurable Testbed (CoNNeCT), served as a test facility for NASA research on radio communications and the Global Positioning System (GPS).
SCAN Testbed on International Space Station (Source: NASA)
The SCAN Testbed was launched on July 20, 2012 on a Japanese H-IIB Transfer Vehicle and installed in the International Space Station to provide an on-orbit, adaptable software-defined radio (SDR) facility with corresponding ground and operational systems. This permitted mission operators to remotely change the functionality of radio communications through software once deployed to space, offering them flexibility to adapt to new science opportunities and recover from anomalies within the science payload or communication system.
The SCAN Testbed payload was used to conduct a variety of experiments with the goal of further advancing other technologies, reducing risks on other space missions, and enabling future mission capabilities.
After seven successful years, and more than 4,200 hours of testing, it was decommissioned June 3, 2019 as it burned up in the trunk of SpaceX CRS-17 upon reentry into Earth’s atmosphere.
Thank you for sharing this, Dan! I had never heard of the SCAN testbed. I can only imagine what it might have been capable of accomplishing from orbit. I dare say there are even more powerful SDRs orbiting the planet at this moment!
As of June 2020, NASA’s Solar Dynamics Observatory – SDO – has now been watching the Sun non-stop for over a full decade. From its orbit in space around Earth, SDO has gathered 425 million high-resolution images of the Sun, amassing 20 million gigabytes of data over the past 10 years. This information has enabled countless new discoveries about the workings of our closest star and how it influences the solar system.
With a triad of instruments, SDO captures an image of the Sun every 0.75 seconds. The Atmospheric Imaging Assembly (AIA) instrument alone captures images every 12 seconds at 10 different wavelengths of light. This 10-year time lapse showcases photos taken at a wavelength of 17.1 nanometers, which is an extreme ultraviolet wavelength that shows the Sun’s outermost atmospheric layer – the corona. Compiling one photo every hour, the movie condenses a decade of the Sun into 61 minutes. The video shows the rise and fall in activity that occurs as part of the Sun’s 11-year solar cycle and notable events, like transiting planets and eruptions. The custom music, titled “Solar Observer,” was composed by musician Lars Leonhard.
I couldn’t find any information about Quindar Tones at the US Space and Rocket Center–although, admittedly, the place is massive and I could have easily overlooked it–so I did a little research when I returned home.
“I’ve always wondered what purpose the ‘beeps’ served that one heard intermittently during the voice communications with the Command and Lunar Modules during the Apollo missions, as well as other space missions.”
Journal Contributor Mike Dinn provides an MP3 clip ( 123k ) from a network audio check that includes numerous quindar tones.
Journal Contributor Markus Mehring replies:
“‘Other space missions’ is quite an accurate observation, since the ‘beeps’, in fact, are still in use today on Shuttle flights, at least on the UHF frequencies.”
“These beeps are called ‘Quindar-Tones’. Their purpose is to trigger the ground station transmitters when there is an outgoing transmission from Earth. The CapCom in the Mission Control Center, who is taking care of communications with the crew, uses his communication gear in a PTT mode exclusively. ‘PTT’ is short for Push-To-Talk, which means that the CapCom presses a button every time and as long as he wants to talk. (The crews back during Apollo – and also today – usually communicate via PTT as well, but they also have the so-called ‘VOX mode’ at their disposal, in which their microphones are voice-triggered by a certain adjustable threshold volume levels. VOX is used when they don’t necessarily have their hands free.)
When the CapCom presses his PTT button to start a transmission, an intro tone (2.525KHz sine wave with a length of 250ms) is generated and triggers the ground station transmitters to send. And when he is finished talking and releases the button again, a slightly lower outro tone (2.475KHz, sine, 250ms) is generated to trigger the ground station transmitters to turn off. So in short, these are remote control trigger tones.
Steve Schindler, an engineer with voice systems engineering at NASA’s Kennedy Space Center, offers the following history of [Quindar Tones] origins.
“Quindar tones, named after the manufacturer of the tone generation and detection equipment, are actually used to turn on and off, or “key,” the remote transmitters at the various tracking stations (Merritt Island Launch Area–now Kennedy Space Center, Bermuda, Australia, etc.) that were used to communicate with the Mercury through Apollo spacecraft and, in some cases, are still used with the Space Shuttle.”
[…]”Although it usually worked well, there were a couple of peculiarities with this system. If the transmitter was keyed and the telephone line connection broken, the transmitter would never get the tone to turn off. To prevent this there was a “transmitter on” light at each remote site that would come on when the transmitter was keyed. Someone was supposed to monitor the circuit and if the audio dropped, but the “transmitter on” light was still on, they would have to manually unkey the transmitter. Also, just before communications was handed over to a new tracking station, the key-unkey tone pair was sent 10 times to ensure that everything was functioning correctly. This was done before the audio was patched to the tracking station’s line so it wasn’t heard in the control room or on NASA Select audio.
The Quindar system was actually built from a piece of equipment that was used to put multiple teletype circuits on a single phone line by means of frequency domain multiplexing. Because replacement parts are no longer available, an “out-of-band signaling” system was installed in 1998 for the transmitters located in the U.S. This system uses a continuous tone that is below the normal audio frequency range. When the tone is present, the transmitters are keyed. When the tone is not present, the transmitters are unkeyed. It worked fine, but the Astronaut Office complained about the lack of tones which everyone had become accustomed to as an alert that a transmission was about to start. So, the Quindar tone generator, which was still installed in case it was necessary to key the transmitters at an overseas site, was re-enabled.
Even though you won’t hear the same Quindar tones in present-day space missions, you can listen until your heart is content at the website Apollo In Real Time.
If you’re fascinated with the NASA audio soundscape in general, you might check out the electronic music duo Quindar featuring longtime Wilco member Mikael Jorgensen, and art historian-curator James Merle Thomas.
Quindar: Mikael Jorgensen & James Merle Thomas. Photo by Chad Ress, Spacesuits by Cassandra C. Jones
Science Friday featured an extended interview with the group in 2017. If you love electronic music–especially if you’re a fan of Wilco, it’s well worth a listen:
Radio Waves: Stories Making Waves in the World of Radio
Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers. To that end: Welcome to the SWLing Post’sRadio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!
Many thanks to SWLing Post contributors Benn, Tony, and Michael Bird for the following tips:
Make no mistake about it: The renaissance of electric vehicle manufacturing has been one of the most significant blessings of innovation in the 21st century. The continued production and voluntary adoption of electric vehicles have made the United States a greener and cleaner nation. However, while EV makers continue working to bring the U.S. forward environmentally, they need to ensure their design methods do not have a negative impact on one of the country’s most crucial national security apparatuses.
As the former administrator of the Federal Emergency Management Agency (FEMA) that oversaw the operations of over 220 declared disasters, I am concerned about what I’ve seen from automakers removing AM radios from vehicles — an action that will make Americans less safe in emergency situations.
Interference between the broadcast reception and the electric motors of certain cars, principally electric vehicles, is the reasoning behind some companies’ decision to eliminate the radio from car dashboards. However, scrapping radio rather than making the signals compatible can severely harm the federal government’s disaster relief efforts.
Federal law mandates that FEMA always possess the capabilities to deliver messages to the American people. To this end, FEMA has spent tens of million dollars and counting perfecting the Primary Entry Point (PEP) stations — consisting mostly of AM stations, but some FM ones as well — that connect to The National Public Warning System.[…]
You probably haven’t heard of Ray Naughton’s feat of science — not many people have. But 55 years ago, the quiet electronics store owner from Birchip, in western Victoria, successfully completed Australia’s first ever moon bounce.
The amateur radio fanatic had spent most of his time alone in a paddock, tinkering away on a 250-metre wide, 30-metre tall antenna capable of bouncing a radio signal off the moon and back again.
Mr Naughton was driven by news that astronauts would soon be walking across its surface.
When that day came, on July 20 1969, Mr Naughton used his antenna to tune into conversations between astronauts and NASA.
A small group of locals watched on in wonder, realising for the first time what their private neighbour had been working on.[…]
NASA will spend 11 months upgrading the only piece of its Deep Space Network that can send commands to the probe, which has crossed into interstellar space.
Voyager 2 has been traveling through space for 43 years, and is now 13 billion miles from Earth. But every so often, something goes wrong.
At the end of January, for instance, the robotic probe executed a routine somersault to beam scientific data back to Earth when an error triggered a shutdown of some of its functions.
“Everybody was extremely worried about recovering the spacecraft,” said Suzanne Dodd, who is the Voyager project manager at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
The mission’s managers on our planet know what to do when such a fault occurs. Although it takes about a day and a half to talk to Voyager 2 at its current distance, they sent commands to restore its normal operations.
But starting on Monday for the next 11 months, they won’t be able to get word to the spry spacecraft in case something again goes wrong (although the probe can still stream data back to Earth). Upgrades and repairs are prompting NASA to take offline a key piece of space age equipment used to beam messages all around the solar system.[…]
The ABC has been forced to delay the release of its five-year blueprint – including job cuts – to prioritise its response to the coronavirus pandemic.
The national broadcaster was due to announce its long-term plan at the end of this month. A three-year funding freeze that took effect last July, stripping $84 million from ABC’s budget, will result in an estimated 200 redundancies.
In an email to staff, managing director David Anderson said, “I think you will agree with me when I say that the current situation with COVID-19 means our focus must be on the welfare of all of you and our role as a public broadcaster in providing the community with timely and credible information in this challenging time for our country.
“For this reason, I’m sure you will understand my decision to postpone the announcement until we are through this period … your patience and professionalism are, as always, greatly appreciated.”
Anderson told employees he would reveal his plan “as soon as we have returned to normal levels of activity”.[…]
Many thanks to SWLing Post contributor, Marty, who shares the following article from Popular Science:
NASA’s solar probe reveals stunning results after swooping in close to the sun
Rogue plasma waves and sideways, 100,000-mile-per-hour solar winds abound.
The sky is full of stars, but only one sits within our reach. Even as close as it is, the sun poses plenty of mysteries that can’t be solved from Earth. Odd patterns in sunlight during solar eclipses suggest that the corona, the sun’s outermost bit of atmosphere, inexplicably burns hundreds of times hotter than its surface. And while researchers can catch whiffs of the solar wind—streams of charged particles emanating from the sun—here on Earth, a lot of valuable data washes away by the time it blows by us. Getting measurements from right up next to the sun is a better way to understand our giant, burning ball of gas.
That’s why NASA’s Parker Solar Probe has spent the last year swooping closer and closer to the sun. In its first two passes it encountered new features that may help explain both the corona’s extreme heat and the origins of the solar wind, researchers announced on Wednesday in a series of four publications in Nature. As humanity’s first close encounter with a stellar environment continues, further observations will help researchers better understand how solar weather affects Earth, as well as how all stars age and die.
“We needed to go right to the source,” said Nicola Fox, director of NASA’s Heliophysics Division in a press conference on Wednesday.
In November 2018 and April of this year, two of Parker’s orbits brought it closer to the sun than any spacecraft had been before. Diving toward the sun and looping around the back, the probe reached about 15 million miles from the star’s surface—roughly six times closer than the distance between the sun and the Earth. At the shortest parts of its dive, the probe matched the speed of the sun’s rotation, in effect hovering above its surface. “We just sit over it, and let that part of the sun kind of wash over us,” says Kelly Korreck, head of Science Operations for one of Parker’s instrument suites that measures the solar wind.
Up close, the sun’s magnetic field and solar wind are both much more intense compared to what researchers can measure here on Earth, giving Parker an alien environment to explore. Korreck likens the craft’s experiences in the strong magnetic field to those of a diver entering the sea. “It’s kind of like going underwater,” she says. “Things sound different. You get different physics effects.”
Two features in particular came as surprises. The first were what the researchers are calling “rogue waves” in the magnetic field, which Parker registered as spikes in intensity and reversals in direction lasting for seconds to minutes as they rolled over the spacecraft. Dubbed Alfvén waves after Hannes Alfvén, a Swedish plasma physicist who won the 1970 Nobel prize in physics for their description, the phenomenon had been observed from Earth but never with such strength.[…]