Floating Spaceports For Future Rockets

September 14, 2020 by Tom Nardi 36 Comments

While early prototypes for SpaceX’s Starship have been exploding fairly regularly at the company’s Texas test facility, the overall program has been moving forward at a terrific pace. The towering spacecraft, which CEO Elon Musk believes will be the key to building a sustainable human colony on Mars, has gone from CGI rendering to flight hardware in just a few short years. That’s fast even by conventional rocket terms, but then, there’s little about Starship that anyone would dare call conventional.

An early Starship prototype being assembled.

Nearly every component of the deep space vehicle is either a technological leap forward or a deviation from the norm. Its revolutionary full-flow staged combustion engines, the first of their kind to ever fly, are so complex that the rest of the aerospace industry gave up trying to build them decades ago. To support rapid reusability, Starship’s sleek fuselage abandons finicky carbon fiber for much hardier (and heavier) stainless steel; a material that hasn’t been used to build a rocket since the dawn of the Space Age.

Then there’s the sheer size of it: when Starship is mounted atop its matching Super Heavy booster, it will be taller and heavier than both the iconic Saturn V and NASA’s upcoming Space Launch System. At liftoff the booster’s 31 Raptor engines will produce an incredible 16,000,000 pounds of thrust, unleashing a fearsome pressure wave on the ground that would literally be fatal for anyone who got too close.

Which leads to an interesting question: where could you safely launch (and land) such a massive rocket? Even under ideal circumstances you would need to keep people several kilometers away from the pad, but what if the worst should happen? It’s one thing if a single-engine prototype goes up in flames, but should a fully fueled Starship stack explode on the pad, the resulting fireball would have the equivalent energy of several kilotons of TNT.

Thanks to the stream of consciousness that Elon often unloads on Twitter, we might have our answer. While responding to a comment about past efforts to launch orbital rockets from the ocean, he casually mentioned that Starship would likely operate from floating spaceports once it started flying regularly:

While history cautions us against looking too deeply into Elon’s social media comments, the potential advantages to launching Starship from the ocean are a bit too much to dismiss out of hand. Especially since it’s a proven technology: the Zenit rocket he references made more than 30 successful orbital launches from its unique floating pad.

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The O-Bahn Busway – Obscure Transit For The Masses

September 10, 2020 by Zoe Skyforest 77 Comments

Around the world, governments and city planners have long struggled with the issue of transport. Getting people where they need to be in a timely fashion is key to making a city a comfortable, attractive place to live. As far as public transport is concerned, this typically consists of buses on the roads, and trams and trains on rails.

Down in the city of Adelaide, Australia, things get a little muddled, however. Nestled in a river valley lies a special transportation network known as the O-Bahn, where buses ride on concrete rails and the drivers can even take their hands off the wheel. The system remains a rarity worldwide, and was spawned by a perfect storm of conflicting requirements.

A Child of Circumstance

In the 1970s, the South Australian government found itself backed into a corner. Facing a booming population in the north-eastern suburbs, new transport links with greater capacity were needed to get people to the central business district. Original plans from the 1960s had called for more freeways to be built all over the city to solve the problem. In the face of stiff public opposition, legislation was passed in 1970 blocking the construction of any new freeways for a full decade, forcing the government to consider alternatives.

O-Bahn buses passing at speed near Stephens Terrace. Buses formerly reached speeds up to 100 km/h on the network; this was dropped to 85 km/h in 2012, adding 20 seconds to the average run. Credit: Lewin Day

Despite plans being shelved, a corridor of land stretching from the city to the north-east had already been acquired for freeway construction. This was retained, and studies were commissioned to determine the best transportation solution to suit the needs of the area. The “North East Adelaide Public Transport Review” suggested light-rail or a busway would be the best solution.

Initial plans were proposed to link the north-east with a light-rail tramway that would connect with the existing tramline from the city proper to Glenelg in the west. However, the City of Adelaide protested the plan, believing that extending the existing tramline to the east would damage the city’s carefully planned structure. Plans were made to rectify this by running part of the line underground, massively increasing costs, and the proposal was shelved.

It was at this time, the guided busway in Essen, Germany came to the attention of the state government. Aiming to help reduce congestion by allowing buses to share tram tunnels, it began as a demonstration which later developed into the Spurbus network. The system offered lower cost and higher flexibility than light rail, and avoided the need to carve up the city to hook in to the existing light rail network. Had Adelaide laid out its existing heavy or light rail networks differently, the O-Bahn might not have gotten a look in. However, back in the early 1980s, it was an easy solution in a sea of difficult choices.

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3D-Printed Thermite Brings The Heat, And The Safety

September 10, 2020 by Kristina Panos 15 Comments

Thermites are a double-edged sword. Packing a tremendous energy density, and eager to produce tremendous heat when ignited, thermite is great for welding train tracks. But sometimes you might be looking for a little more finesse. A new approach to 3D printing thermites might just be able to tame the beast.

Most of us do our soldering while sitting safely indoors in a comfortable climate. The biggest dangers we’re likely to face are burnt fingertips, forgetting the heat shrink, or accidentally releasing the smoke monster. But outside of our homes and workshops, there’s a lot of extreme joining of metals going on. No matter where it’s done, welding and brazing in the field requires a lot of equipment, some of which is unwieldy and even more difficult to move around in harsh conditions.

Welding railroad tracks with thermite. Image via YouTube

The utility of brazing is limited by all the complex scaffolding of hardware required to support it. This limiting factor and the discovery of thermite led to exothermic welding, which uses an energetic material to provide enough heat to melt a filler metal and join the pieces. Energetic materials can store a lot of chemical energy and forcefully release it in a short period of time.

Thermites are made of metal oxide and metal powder, often iron oxide and aluminium. When ignited by a source of high heat, thermite compounds undergo an exothermic reduction-oxidation (redox) reaction as the aluminium reduces the number of electrons in the iron oxide atoms. More heat makes the reaction run faster, generating more heat, and so on. The result is molten iron and aluminium oxide slag.

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Size Does Matter When It Comes To SD Cards

September 8, 2020 by Zoe Skyforest 54 Comments

The SD card first burst onto the scene in 1999, with cards boasting storage capacities up to 64 MB hitting store shelves in the first quarter of 2000. Over the years, sizes slowly crept up as our thirst for more storage continued to grow. Fast forward to today, and the biggest microSD cards pack up to a whopping 1 TB into a package smaller than the average postage stamp.

However, getting to this point has required many subtle changes over the years. This can cause havoc for users trying to use the latest cards in older devices. To find out why, we need to take a look under the hood at how SD cards deal with storage capacity. Continue reading “Size Does Matter When It Comes To SD Cards” →

Teardown: Mini GPS Jammer

September 8, 2020 by Tom Nardi 144 Comments

If you spend enough time trolling eBay for interesting electronic devices to take apart, you’re bound to start seeing suggestions for some questionable gadgets. Which is how I recently became aware of these tiny GPS jammers that plug directly into an automotive 12 V outlet. Shipped to your door for under $10 USD, it seemed like a perfect device to rip open in the name of science.

Now, you might be wondering what legitimate uses such a device might have. Well, as far as I’m aware, there aren’t any. The only reason you’d want to jam GPS signals in and around a vehicle is if you’re trying to get away with something you shouldn’t be doing. Maybe you’re out driving a tracked company car and want to enjoy a quick two hour nap in a parking lot, or perhaps you’re looking to disable the integrated GPS on the car you just stole long enough for you to take it to the chop shop. You know, as one does.

But we won’t dwell on the potentially nefarious reasons that this device exists. Hackers have never been too choosy about the devices they investigate and experiment with, and there’s no reason we should start now. Instead, let’s take this piece of gray-area hardware for a test drive and see what makes it tick.

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Cousteau’s Proteus Will Be The ISS Of The Seas

September 7, 2020 by Kristina Panos 32 Comments

The Earth’s oceans are a vast frontier that brims with possibilities for the future of medicine, ocean conservation, and food production. They remain largely unexplored because of the physical limits of scuba diving. Humans can only dive for a few hours each day, and every minute spent breathing compressed air at depth must be paid for with a slower ascent to the surface. Otherwise, divers could develop decompression sickness from nitrogen expanding in the bloodstream.

An illustration of the Conshelf 3 habitat. Image via Medium

In the 1960s, world-famous oceanographer Jacques Cousteau built a series of small underwater habitats to extend the time that he and other researchers were able to work. These sea labs were tethered to a support ship with a cable that provided air and power.

Cousteau’s first sea lab, Conshelf 1 (Continental Shelf Station) held two people and was stationed 33 feet deep off the coast of Marseilles, France. Conshelf 2 sheltered six people and spent a total of six weeks under the Red Sea at two different depths.

Conshelf 3 was Cousteau’s most ambitious habitat design, because it was nearly self-sufficient compared to the first two. It accommodated six divers for three weeks at a time and sat 336 feet deep off the coast of France, near Nice. Conshelf 3 was built in partnership with a French petrochemical company to study the viability of stationing humans for underwater oil drilling (before we had robots for that), and included a mock oil rig on the nearby ocean floor for exercises.

Several underwater habitats have come and gone in the years since the Conshelf series, but each has been built for a specific research project or group of tasks. There’s never really been a permanent habitat established for general research into the biochemistry of the ocean.

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The Astronomical Grit Of Ronald McNair

September 3, 2020 by Kristina Panos 23 Comments

There is more than one way to lead a successful life. Some people have all the opportunity in the world laid out before them, and it never does them any good. Others have little more than the determination and desire they’ve dredged up within themselves, and that grit turns out to be the abrasive that smooths the path ahead.

Ronald McNair succeeded despite poverty, racism, and an education system designed to keep Black people down. He became an accidental revolutionary at the age of nine, when he broke the color barrier in his small South Carolina town via the public library. This act of defiance in pursuit of education would set the course for his relatively short but full life, which culminated in his career as a Space Shuttle mission specialist.

Rule-Breaker with a Slide Rule

Ronald McNair was born October 21, 1950 in Lake City, South Carolina, the second of three sons, to Pearl and Carl McNair. His mother was a teacher, and encouraged his love of reading. Ronald’s father, Carl was an auto mechanic who never finished high school and always regretted it. Though the family was poor, Ron grew up surrounded by books, music, and support.

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