Kilopower: NASA’s Offworld Nuclear Reactor

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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Secret Messages Could Be Hiding In Your Server Logs

[Ryan Flowers] writes in with a clever little hack that can allow you to hide data where nobody is going to go looking for it. By exploiting the fact that a web server will generally log all HTTP requests whether or not it’s valid, he shows how you can covertly send a message by asking the server for a carefully crafted fictitious URL.

We aren’t talking about requesting “yousuck.txt” from the server that hosts your least favorite website, either. As [Ryan] demonstrates, you can compress a text file, encode it with uuencode, and then send it line by line to the destination server with curl. He shows how the process, which he calls “CurlyTP” can be done manually on the command line, but it would be a simple matter of wrapping it up in a Bash script.

To get the message back, you just do the opposite. Use grep to find the lines in the log file that contain the encoded data, and then put them through uudecode to get the original text back. Finding the appropriate lines in the log file is made easier by prepending a prearranged keyword to the beginning of the URL requests. The keyword can be changed for each message to make things easier to keep track of.

If you’re still wondering why anyone would go through the trouble to do this, [Ryan] provides an excellent example: a covert “dead drop” where people could leave messages they’d rather not send through the usual channels. As long as the sender used a service to mask their true IP address, they could anonymously deliver messages onto the server without having to use any special software or protocol they might not have access to. Even the most restrictive firewalls and security measures aren’t likely to be scanning URLs for compressed text files.

We’ve seen web-based dead drops done with Python in the past, and even purpose built “PirateBoxes” that allow people to covertly exchange files, but we like how this method doesn’t require any special configuration on the server side. You should check your server logs, somebody might be trying to tell you something.

Finely Machined Valve Controls Miniature RC Hydraulics

Hydraulic components are the industrial power transmission version of LEGO. Pumps, cylinders, valves – pretty much everything is standardized, and fitting out a working system is a matter of picking the right parts and just plumbing everything together. That’s fine if you want to build an excavator or a dump truck, but what if you want to scale things down?

Miniature hydraulic systems need miniature components, of which this homebrew hydraulic valve made by [TinC33] is a great example. (Video embedded below.) If you’re curious about why anyone would need these, check out the tiny hydraulic cylinders he built a while back, wherein you’ll learn that miniature RC snowplows are a thing. The video below starts with a brief but clear explanation about how hydraulic circuits work, as well as an explanation of the rotary dual-action proportional valve he designed. All the parts are machined by hand in the lathe from aluminum and brass stock. The machining operations are worth watching, but if you’re not into such things, skip to final assembly and testing at 13:44. The valve works well, providing very fine control of the cylinder and excellent load holding, and there’s not a leak to be seen. Impressive.

[TinC33] finishes the video with a tease of a design for multiple valves in a single body. That one looks like it might be an interesting machining challenge, and one we’d love to see.

Thanks to [mgsouth] for the tip.