Persnickety

24 Apr 19
Homemaker's Habitat

This easy Leftover Ham One-Pot Pasta is a great way to use up leftover ham and makes its own better-for-you magical cream sauce while it cooks. It’s a kid-approved easy weeknight dinner.

24 Apr 19
One Foot In, One Foot Back

As a writer the most important tools I have are the words I choose. On some of my posts it can take over an hour just to have a sentence convey the message I have in my head or heart. When it comes to speaking, I often stumble over my words and part of the […]

23 Apr 19
Escape to Which Mountain

Yesterday was a long day that was both important and incredibly exhausting, complete with a whopper of a caffeine headache for most of the day because I’m officially off the sauce. I woke up in Raleigh at 7:30am, rented a car, drove 45 minutes north on a stretch of highway that I have been on […]

23 Apr 19
Tamarack's Guide Service

So I’m here at home with my family for 10 days. It’s been 53 days since I’ve seen any of them. Which was a long time, longest I’ve been away from them. So that had its ups and downs. Luckily I have trout to occupy the mind. After spending almost the entire 53 days outside […]

23 Apr 19
Alphabet Resolutions

After my goals post last month, I had a few readers ask about my process for my photo routine, so today’s post is all about how I get the thousands of pictures on my iPhone sorted, stored, and backed up in a way that is most useful for me. I’m hoping this will be helpful […]

23 Apr 19
Eye of Horus Metaphysical | Tarot Psychic Readings - 612-872-1292

Greenery greens! Flowers blossom in vibrant color and scent as the new moon in Taurus bears its fruitful horns on May 4 (5:45 pm, CDT). The five senses light up as sensual pleasures are heightened! Creature comforts and earthly delights reign supreme. The Aries ram charged ahead forcefully this spring (3/21-4/19), yet Saturn in Capricorn […]

23 Apr 19
Simple Southern

After the Christmas parade debacle, Miss Mule was mad at me for a solid 3 months. She wouldn’t get anywhere near a trailer without an absurd amount of effort on my part, she didn’t want to be ridden, and she was generally salty. You may ask how I know that she didn’t want to be […]

22 Apr 19
Hackaday
There’s no shortage of ways a satellite in low Earth orbit can fail during the course of its mission. Even in the best case scenario, the craft needs to survive bombardment by cosmic rays and tremendous temperature variations. To have even a chance of surviving the worst, such as a hardware fault or collision with a rogue piece of space garbage, it needs to be designed with robust redundancies which can keep everything running in the face of systemic damage. Of course, before any of that can even happen it will need to survive the wild ride to space; so add high-G loads and intense vibrations to the list of things which can kill your expensive bird. After all the meticulous engineering and expense involved in putting a satellite into orbit, you might think it would get a hero’s welcome at the end of its mission. But in fact, it’s quite the opposite. The great irony is that after all the time and effort it takes to develop a spacecraft capable of surviving the rigors of spaceflight, in the end, its operators will more than likely command the craft to destroy itself by dipping its orbit down into the Earth’s atmosphere. The final act of a properly designed satellite will likely be to commit itself to the same fiery fate it had spent years or even decades avoiding. You might be wondering how engineers design a spacecraft that is simultaneously robust enough to survive years in the space environment while at the same time remaining just fragile enough that it completely burns up during reentry. Up until fairly recently, the simple answer is that it wasn’t really something that was taken into account. But with falling launch prices promising to make space a lot busier in the next few years, the race is on to develop new technologies which will help make sure that a satellite is only intact for as long as it needs to be. The Sky is Falling A piece of Skylab that crashed in Australia The possibility of debris surviving reentry and hitting the ground is nothing new, and there are documented cases going back for about as long as we’ve been shooting things into space. Arguably the most famous example was in 1979, when wreckage from Skylab was strewn all over the Australian outback. The largest pieces, such as the tanks that held oxygen aboard America’s most persnickety space station, tipped the scales at hundreds of kilograms. Luckily these massive objects came down in one of the most scarcely populated stretches of land on the planet, but had they come down in a major city the damage and risk to human life could have been considerable. What’s changed is how many objects we can expect to be reentering the atmosphere in the near future. When only the world superpowers had the ability to put something into space, it was relatively easy to keep track of when things were coming back down. But increased competition has dramatically reduced the cost of putting satellites into orbit, and now companies are looking at space investments which would have been simply impossible just a decade ago. Companies like SpaceX, OneWeb, and Samsung are eyeing satellite mega-constellations consisting of thousands of individual spacecraft, and each one of them will eventually come careening back down through the atmosphere at the end of its nominal lifespan. In a letter dated February 26th, the Federal Communication Commission specifically asked SpaceX to detail their plans for deorbiting the thousands of satellites in their proposed Starlink network. They wanted to know if SpaceX can ensure that the craft will reenter over the ocean, and if not, to estimate the likelihood that falling debris could cause material damage or human casualties. The letter ends by stating that SpaceX’s application for Starlink approval could be dismissed if this information was not provided to the satisfaction of the FCC. Unacceptable Risk Directing a spacecraft to renter over the ocean has always been the standard way of ensuring that any debris that survive won’t cause any problems on the ground. Since most of the planet’s surface area is ocean anyway, this ends up being a relatively simple thing to do assuming your spacecraft is functioning normally and is capable of maneuvering itself. Though mistakes do happen; Skylab was actually supposed to reenter south of Africa, a slight error in the calculations caused it to overshoot considerably eastwards. Two prototype Starlink satellites before launch But SpaceX’s proposed Starlink satellites (and others like it) are something of a special case. They utilize high efficiency Hall-effect propulsion which is ideal for occasional orbit adjustments and station-keeping, but lacks the thrust necessary to put the craft on a targeted reentry trajectory. In other words, the satellites are capable of lowering their orbit enough to ensure they will burn up, but can’t pinpoint where it will happen with sufficient accuracy to make any guarantees. That might be an acceptable risk when dealing with just a single satellite, but long-term Starlink plans call for as many as twelve thousand of them. With that many craft in play, the chances that one of them could break up over a populated area is simply too high. In their official response to the FCC, SpaceX explained that while they were unable to guarantee that Starlink satellites would only reenter the atmosphere over the ocean, they had come up with a solution which would make it unnecessary. After “extensive research and investment”, SpaceX says they’ve refined the design of their Starlink satellites to ensure they’ll completely burn up in the atmosphere. Design for Demise The idea of designing satellites in such a way that they will burn up entirely during a normal reentry has been floating around for decades, but so far has struggled to catch on. Referred to as “Design for Demise” or D4D in the industry, its biggest proponent has arguably been the European Space Agency which has made it a central theme in their overall “Clean Space” initiative. As you might imagine it’s a complex subject, but at the risk of oversimplifying things, there are essentially two main approaches: designs which break up into smaller pieces upon entering the atmosphere, and the use of materials which cannot survive the intense heat of reentry. These two ideas are not mutually exclusive, and indeed would likely be used together for best results. For example, rather than holding a satellite together with nuts and bolts, it could be glued together with epoxies which are formulated to break down at high temperatures. Once the spacecraft hits the atmosphere and starts warming up, the epoxy gives way and the structure simply falls apart. Not only does this technique reduce the number of large objects that could conceivably come through the atmosphere intact, but it also opens up the interior of the spacecraft to the flow of hot atmospheric gasses which will promote more complete burning. A typical reaction wheel module. Even still, there are some components of the average satellite which are robust enough that they could conceivably survive. Likely candidates are titanium propellant tanks, silicon carbide mirrors (used in optical telescopes or laser communications systems), the iron cores of the Hall-effect thrusters, and the heavy stainless steel reaction wheels used to provide attitude control for the spacecraft. These components pose a considerably trickier problem, as the materials used in their construction were obviously selected for a reason. As an example, replacing a stainless steel reaction wheel with an aluminum one of the same diameter simply wouldn’t work due to the differences in density. The whole system would need to be redesigned to take into account the material change. According to their official response to the FCC, SpaceX says they’ve replaced these problem components with versions which they can guarantee won’t survive reentry. If true, it would be a huge milestone for D4D design, and likely the yardstick by which future large-scale satellite constellations will be measured. But not everyone is convinced that SpaceX has solved this complex problem as neatly as they say. In a statement to IEEE Spectrum, professor of mechanical and aerospace engineering at the University at Buffalo John Crassidis said he believes the claims are a bit too bold: “Anything can come through the atmosphere if you hit at just the right angle. If they’re guaranteeing it’s not going to cause an issue, then I’m going to have call BS on it.”
22 Apr 19
Stacey on IoT | Internet of Things news and analysis

If you’ve wandered through a large airport in the last few years, you’ve likely seen a small, white, standalone terminal with four buttons that you could push to register how happy you were with the experience you just had while going through security. Those terminals are the work of Finnish company HappyOrNot, which launched a decade […]

22 Apr 19
Trailer Girl's Guide to Happy Camping

Let me begin by telling you about Fishermen’s Bend.  We were driving from Seattle to Southern California and were passing through the Sacramento area.  We were just staying one night.  Before the days of Yelp and Google reviews, one had to rely on RV Park Guides.  They were kind of like the motel guides you can get from AAA, […]

21 Apr 19
flyandtrips.com

The number of American travelers visiting Cuba was up 15.2% year-over-year by the end of 2018. But just as things were starting to rebound, new sanctions from the Trump administration could derail future travel plans. If you’ve ever had a desire to visit this stuck-in-time island nation, now’s your chance. With plenty of flights still …

21 Apr 19
RVArt Review

ANIMAL CONTROL: A BAD DAWG TALE A Theater Review by Julinda D. Lewis At: The Firehouse Theatre, 1609 W. Broad Street, RVA 23220 Performances: April 17 – May 12, 2019 Ticket Prices: $15/student; $25/military; $35/general admission Info: (804) 355-2001 or firehousetheatre.org   Richmonders who are familiar with the name Chandler Hubbard probably know him as an […]

20 Apr 19
Trendy Kids Clothing

Fashion isn’t just for grown-ups any more. These days, children’s clothing can be just as chic and stylish as the items you typically find in stores geared towards adult fashion-bugs. This is especially true of girl’s clothing. As exemplified by notable designer kids brands, such as Lemon Loves Lime, your little one can be the […]

18 Apr 19
flyandtrips.com

During a speech at the Biltmore Hotel in Coral Gables, Florida, on Wednesday, National Security Advisor John Bolton said the Trump administration is imposing new sanctions on Cuba. “We are also announcing that the Department of the Treasury will implement further regulatory changes to restrict nonfamily travel to Cuba,” Bolton said. “These new measures will …