HAMNET Report 22 July 2018

The website phys-org tells us that, for scientists watching the Red Planet Mars from data gathered by NASA’s orbiters, the past month has been a windfall. “Global” dust storms, where a runaway series of storms creates a dust cloud so large it envelops the planet, only appear every six to eight years (that’s three to four Mars years). Scientists still don’t understand why or how exactly these storms form and evolve.

In June, one of these dust events rapidly engulfed the planet. Scientists first observed a smaller-scale dust storm on May 30. By June 20, it had gone global.

For the Opportunity rover, that meant a sudden drop in visibility from a clear, sunny day to that of an overcast one. Because Opportunity runs on solar energy, scientists had to suspend science activities to preserve the rover’s batteries. As of July 18th, no response has been received from the rover.

Luckily, all that dust acts as an atmospheric insulator, keeping night-time temperatures from dropping down to lower than what Opportunity can handle. But the nearly 15-year-old rover isn’t out of the woods yet: it could take weeks, or even months, for the dust to start settling. Based on the longevity of a 2001 global storm, NASA scientists estimate it may be early September before the haze has cleared enough for Opportunity to power up and call home.

When the skies begin to clear, Opportunity’s solar panels may be covered by a fine film of dust. That could delay a recovery of the rover as it gathers energy to recharge its batteries. A gust of wind would help, but isn’t a requirement for a full recovery..

While the Opportunity team waits in earnest to hear from the rover, scientists on other Mars missions have gotten a rare chance to study this head-scratching phenomenon.

The Mars Reconnaissance Orbiter, Mars Odyssey, and Mars Atmosphere and Volatile EvolutioN (MAVEN) orbiters are all tailoring their observations of the Red Planet to study this global storm and learn more about Mars’ weather patterns. Meanwhile, the Curiosity rover is studying the dust storm from the Martian surface.

In other news, the race to produce safe, powerful and affordable solid-state lithium batteries is accelerating and recent announcements about game-changing research using a solid non-flammable ceramic electrolyte known as garnet has some in the race calling it revolutionary.

“This is a paradigm shift in energy storage,” said Kelsey Hatzell, assistant professor of mechanical engineering. A paper describing her novel research on the failure points of a garnet electrolyte was published online in March in the American Chemical Society’s Energy Letters, which was among the most read ACS Letters articles that month.

Lithium-ion batteries typically contain a liquid organic electrolyte that can catch fire. The fire risk is eliminated by the use of a non-flammable garnet-based electrolyte. Replacing liquid electrolytes with a solid organic like garnet also potentially lowers the cost by increasing battery life.

“Solid-state batteries are desirable for all-electric vehicles and other applications where energy storage and safety are paramount,” Hatzell said.

Hatzell’s team tested Lithium lanthanum Zirconium Oxide or LLZO – a garnet-type material that shows great promise for all-solid-state battery applications due to its high Li-ion conductivity and its compatibility with Li metal.

“Understanding the failure mechanisms within these electrolyte systems is critical for designing resilient solid electrolyte systems,” said Hatzell.

I’m hoping that the search for the ideal lithium-based battery system that is light-weight and long-lasting is almost over. Thanks to phys-org for these inserts.

The ARES E-letter reports that, for the first time in the history of amateur communications support of Cooperstown, New York, area public events, high speed video and other data networking on the microwave bands were employed, implementing a mesh network in conjunction with the more traditional simplex VHF FM operations. In the past, the Cooperstown Triathlon run that courses through picturesque Glimmerglass State Park has been supported by Otsego County ARES/RACES with traditional VHF ops, but this year the group added amateur high speed video, enabling remote monitoring of the wooded race course, providing an enhanced, significant situational awareness for race officials.

With the leadership of John Rudolph, N2YP, of Unadilla, New York, and Brian Webster, N2KGC, of Cooperstown, a local area network was established to provide remote control and image transmission to and from remote TV cameras. The main net control station was set up at race headquarters, with the cameras placed at strategic sites around the race course. The real-time video was monitored by the race coordinators.

Along with the employment of the video system, the usual VHF FM portables were also deployed: A simplex frequency was used with backup of the 146.640 MHz Cooperstown repeater for the operators assisting officials with race participant and spectator safety.

The video links/networking used the mesh mode. Remote control of the cameras included full tilt and pan capabilities. Signal to noise ratios were good, and imaging was clear and smooth.

The amateur bands at 900 MHz, 2.4 GHz, 3.4 GHz and 5 GHz can be employed, with the Otsego group using 2.4 GHz channels for its network nodes.

There was absence of interference and a low noise floor, increasing the range of the small transmitters. The use of high-gain antennas at both ends helped with signal strengths, image quality, and hence, efficiency. Inexpensive Internet-protocol (IP) cameras were employed. The 5 GHz band was reserved as a backup, but its use was found to be unnecessary.

A portion of the network build was simply the firmware uploaded to the Ubiquiti® 2.4 GHz radios. Since the radios are designed to work in frequency bands all over the world, the firmware can take advantage of the radio’s ability to move to the amateur portions of the bands readily.

Thank you to ARES for these extracts from their newsletter.

This is Dave Reece ZS1DFR reporting for HAMNET in South Africa.