3D Printing May Be The Key To Practical Scramjets

September 3, 2019 by Tom Nardi 32 Comments

The first scramjet, an airbreathing jet engine capable of pushing an aircraft beyond Mach 5, was successfully flown in the early 1990s. But while pretty much any other technology you could imagine has progressed by leaps and bounds in the nearly 30 years that have passed, the state-of-the-art in hypersonic scramjets hasn’t moved much. We still don’t have practical hypersonic aircraft, military or otherwise, and any missiles that travel at those sort of speeds are rocket powered.

This is somewhat surprising since, at least on paper, the operating principle of the scramjet is simplicity itself. Air rushing into the engine is compressed by the geometry of the inlet, fuel is added, the mixture is ignited, and the resulting flow of expanded gases leaves the engine faster than it entered. There aren’t even any moving parts inside of a scramjet, it’s little more than a carefully shaped tube with fuel injectors and ignitors in it.

Unfortunately, pulling it off in practice is quite a bit harder. Part of the problem is that a scramjet doesn’t actually start working until the air entering the engine’s inlet is moving at around Mach 4, which makes testing them difficult and expensive. It’s possible to do it in a specially designed wind tunnel, but practically speaking, it ends up being easier to mount the engine to the front of a conventional rocket and get it up to speed that way. The downside is that such flights are one-way tickets, and end with the test article crashing into the ocean once it runs out of fuel.

But the bigger problem is that the core concept is deceptively simple. It’s easy to say you’ll just squirt some jet fuel into the stream of compressed air and light it up, but when that air is moving at thousands of miles per hour, keeping it burning is no small feat. Because of this, the operation of a scramjet has often been likened to trying to light a match in a hurricane; the challenge isn’t in the task, but in the environment you’re trying to perform it in.

Now, both Aerojet Rocketdyne and Northrop Grumman think they may have found the solution: additive manufacturing. By 3D printing their scramjet engines, they can not only iterate through design revisions faster, but produce them far cheaper than they’ve been able to in the past. Even more importantly, it enables complex internal engine geometries that would have been more difficult to produce via traditional manufacturing.

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Global Radiation Montoring And Tracking Nuclear Disasters At Home

August 28, 2019 by Lewin Day 10 Comments

Many of us don’t think too much about radiation levels in our area, until a nuclear disaster hits and questions are raised. Radiation monitoring is an important undertaking, both from a public health perspective and as a way to monitor things like weapon development. So why is it done, how is it done, and what role can concerned citizens play in keeping an eye on things?

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Kilopower: NASA’s Offworld Nuclear Reactor

August 28, 2019 by Tom Nardi 107 Comments

Here on Earth, the ability to generate electricity is something we take for granted. We can count on the sun to illuminate solar panels, and the movement of air and water to spin turbines. Fossil fuels, for all their downsides, have provided cheap and reliable power for centuries. No matter where you may find yourself on this planet, there’s a way to convert its many natural resources into electrical power.

But what happens when humans first land on Mars, a world that doesn’t offer these incredible gifts? Solar panels will work for a time, but the sunlight that reaches the surface is only a fraction of what the Earth receives, and the constant accumulation of dust makes them a liability. In the wispy atmosphere, the only time the wind could potentially be harnessed would be during one of the planet’s intense storms. Put simply, Mars can’t provide the energy required for a human settlement of any appreciable size.

The situation on the Moon isn’t much better. Sunlight during the lunar day is just as plentiful as it is on Earth, but night on the Moon stretches for two dark and cold weeks. An outpost at the Moon’s South Pole would receive more light than if it were built in the equatorial areas explored during the Apollo missions, but some periods of darkness are unavoidable. With the lunar surface temperature plummeting to -173 °C (-280 °F) when the Sun goes down, a constant supply of energy is an absolute necessity for long-duration human missions to the Moon.

Since 2015, NASA and the United States Department of Energy have been working on the Kilopower project, which aims to develop a small, lightweight, and extremely reliable nuclear reactor that they believe will fulfill this critical role in future off-world exploration. Following a series of highly successful test runs on the prototype hardware in 2017 and 2018, the team believes the miniaturized power plant could be ready for a test flight as early as 2022. Once fully operational, this nearly complete re-imagining of the classic thermal reactor could usher in a whole new era of space exploration.

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Following Pigs: Building An Injectable Livestock Tracking System

August 27, 2019 by Sean Boyce 43 Comments

I’m often asked to design customer and employee tracking systems. There are quite a few ways to do it, and it’s an interesting intersection of engineering and ethics – what information is reasonable to collect in different contexts, anonymizing and securely storing it, and at a fundamental level whether the entire system should exist at all.

On one end of the spectrum, a system that simply counts the number of people that are in your restaurant at different times of day is pretty innocuous and allows you to offer better service. On the other end, when you don’t pay for a mobile app, generally that means your private data is the product being bought and sold. Personally, I find that the whole ‘move fast and break things’ attitude, along with a general disregard for the privacy of user data, has created a pretty toxic tech scene. So until a short while ago, I refused to build invasive tracking systems – then I got a request that I simply couldn’t put aside…

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Linux Fu: It’s A Trap!

August 26, 2019 by Al Williams 14 Comments

It is easy to think that a Linux shell like Bash is just a way to enter commands at a terminal. But, in fact, it is also a powerful programming language as we’ve seen from projects ranging from web servers to simple utilities to make dangerous commands safer. Like most programming languages, though, there are multiple layers of complexity. You can spend a little time and get by or you can invest more time and learn about the language and, hopefully, write more robust programs.

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The Satellite Phone You Already Own: From Orbit, UbiquitiLink Will Look Like A Cell Tower

August 26, 2019 by Dan Maloney 54 Comments

For anyone that’s ever been broken down along a remote stretch of highway and desperately searched for a cell signal, knowing that a constellation of communications satellites is zipping by overhead is cold comfort indeed. One needs specialized gear to tap into the satphone network, few of us can justify the expense of satellite phone service, and fewer still care to carry around a brick with a chunky antenna on it as our main phone.

But what if a regular phone could somehow leverage those satellites to make a call or send a text from a dead zone? As it turns out, it just might be possible to do exactly that, and a Virginia-based startup called UbiquitiLink is in the process of filling in all the gaps in cell phone coverage by orbiting a constellation of satellites that will act as cell towers of last resort. And the best part is that it’ll work with a regular cell phone — no brick needed.

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Airport Runways And Hashtags — How To Become A Social Engineer

August 23, 2019 by Sharon Lin 11 Comments

Of the $11.7 million companies lose to cyber attacks each year, an estimated 90% begin with a phone call or a chat with support, showing that the human factor is clearly an important facet of security and that security training is seriously lacking in most companies. Between open-source intelligence (OSINT) — the data the leaks out to public sources just waiting to be collected — and social engineering — manipulating people into telling you what you want to know — there’s much about information security that nothing to do with a strong login credentials or VPNs.

There’s great training available if you know where to look. The first time I heard about WISP (Women in Security and Privacy) was last June on Twitter when they announced their first-ever DEFCON Scholarship. As one of 57 lucky participants, I had the chance to attend my first DEFCON and Black Hat, and learn about their organization.

Apart from awarding scholarships to security conferences, WISP also runs regional workshops in lockpicking, security research, cryptography, and other security-related topics. They recently hosted an OSINT and Social Engineering talk in San Francisco, where Rachel Tobac (three-time DEFCON Social Engineering CTF winner and WISP Board Member) spoke about Robert Cialdini’s principles of persuasion and their relevance in social engineering.

Cialdini is a psychologist known for his writings on how persuasion works — one of the core skills of social engineering. It is important to note that while Cialdini’s principles are being applied in the context of social engineering, they are also useful for other means of persuasion, such as bartering for a better price at an open market or convincing a child to finish their vegetables. It is recommended that they are used for legal purposes and that they result in positive consequences for targets. Let’s work through the major points from Tobac’s talk and see if we can learn a little bit about this craft.

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