Flying The Infinite Improbability Drive

Not since the cold fusion confusion of 1989 has the pop science media industry had a story like the EmDrive. The EmDrive is a propellantless thruster – a device that turns RF energy into force. If it works, it will revolutionize any technology that moves. Unlike rocket motors that use chemicals, cold gas, ions, or plasma, a spacecraft equipped with an EmDrive can cruise around the solar system using only solar panels. If it works, it will violate the known laws of physics.

After being tested in several laboratories around the world, including Eagleworks, NASA’s Advanced Propulsion Physics Laboratory, the concept of a device that produces thrust from only electricity is still not disproven, ridiculed, and ignored. For a device that violates the law of conservation of momentum, this is remarkable. Peer review of several experiments are ongoing, but [Paul] has a much more sensational idea: he’s building an EmDrive that will propel a cubesat.

Make no mistake, our current understanding of the universe is completely incompatible with the EmDrive. The idea of an engine that dumps microwave energy into a metal cone and somehow produce thrust is on the fringes of science. No sane academic physicist would pursue this line of research, and the mere supposition that the EmDrive might work is irresponsible. Until further peer-reviewed experiments are published, the EmDrive is the fanciful dream of a madman. That said, if it does work, we get helicarriers. Four EmDrives mounted to a Tesla Roadster would make a hovercar. Your grandchildren would only see Earth’s sun as a tiny speck in the night sky.

This isn’t [Paul]’s first attempt to create a working propellantless thruster. For last year’s Hackaday Prize, [Paul] built a baby EmDrive. Unlike every other EmDrive experiment that used 2.4GHz microwaves, [Paul] designed his engine to operate on 22 to 26 GHz. This means [Paul]’s is significantly smaller and can easily fit into a cubesat. If it works, this cubesat will be able to maintain its orbit indefinitely, fly to the moon and back, or go anywhere in the solar system provided the solar panels get enough light.

While [Paul]’s motivations in creating a citizen science version of the EmDrive are laudable, Hackaday.io’s own baby EmDrive does not display the requisite scientific rigor for a project of this magnitude. Experimental setups are ill-defined, graph axes are unlabeled, and there is not enough information to properly critique [Paul]’s baby EmDrive experiments.

That said, we can’t blame a guy for trying, and the EmDrive is still an active area of research with several papers under peer review. [Paul]’s plan of putting an EmDrive into orbit is putting the cart several miles ahead of the horse, but it is still a very cool project for this year’s Hackaday Prize.

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A $1000 Tiny Personal Satellite

If you ever read any old magazines, you might be surprised at how inexpensive things used to be. A U.S. postage stamp was six cents, a gallon of gas was $0.34, and the same amount of milk was $1.07. Everything is relative, though. The average household income back then was under $8,000 a year (compared to over $53,000 a year in 2014). So as a percentage of income, that milk actually cost about seven bucks.

The same is true of getting into orbit. Typical costs today just to get something into orbit has gone from–no pun intended–astronomical, to pretty reasonable. Lifting a pound of mass on the Space Shuttle cost about $10,000. On an Atlas V, it costs about $6,000. A Falcon Heavy (when it launches) will drop the cost to around $1,000 or so. Of course, that’s just the launch costs. You still have to pay for whatever you want to put up there. Developing a satellite can be expensive. Very expensive.

Continue reading “A $1000 Tiny Personal Satellite”

32C3: So You Want to Build a Satellite?

[INCO] gave this extremely informative talk on building a CubeSat. CubeSats are small satellites that piggyback on the launches of larger satellites, and although getting a 10 cm3 brick into orbit is cheap, making it functional takes an amazing attention to detail and redundant design.

[INCO] somehow talks through the entire hour-long presentation at a tremendous speed, all the while remaining intelligible. At the end of the talk, you’ve got a good appreciation for the myriad pitfalls that go along with designing a satellite, and a lot of this material is relevant, although often in a simpler form, for high altitude balloon experiments.

satellite_2-shot0002CubeSats must be powered down during launch, with no radio emissions or anything else that might interfere with the rocket that’s carrying them. The satellites are then packed into a box with a spring, and you never see or hear from them again until the hatch is opened and they’re pushed out into space.

[INCO] said that 50% of CubeSats fail on deployment, and to avoid being one of the statistics, you need to thoroughly test your deployment mechanisms. Test after shaking, being heated and cooled, subject to low battery levels, and in a vacuum. Communication with the satellite is of course crucial, and [INCO] suggests sending out a beacon shortly after launch to help you locate the satellite at all.

satellite_2-shot0003Because your satellite is floating out in space, even tiny little forces can throw it off course. Examples include radiation pressure from the sun, and anything magnetic in your satellite that will create a torque with respect to the Earth’s magnetic field. And of course, the deployment itself may leave your satellite tumbling slightly, so you’re going to need to control your satellite’s attitude.

Power is of course crucial, and in space that means solar cells. Managing solar cells, charging lithium batteries, and smoothing out the power cycles as the satellite enters the earth’s shadow or tumbles around out of control in space. Frequent charging and discharging of the battery is tough on it, so you’ll want to keep your charge/discharge cycles under 20% of the battery’s nominal capacity.

mpv-shot0001In outer space, your satellite will be bombarded by heavy ions that can short-circuit the transistors inside any IC. Sometimes, these transistors get stuck shorted, and the only way to fix the latch-up condition is to kill power for a little bit. For that reason, you’ll want to include latch-up detectors in the power supply to reset the satellite automatically when this happens. But this means that your code needs to expect occasional unscheduled resets, which in turn means that you need to think about how to save state and re-synchronize your timing, etc.

In short, there are a ridiculous amount of details that you have to attend to and think through before building your own CubeSat. We’ve just scratched the surface of [INCO]’s advice, but if we had to put the talk in a Tweet, we’d write “test everything, and have a plan B whenever possible”. This is, after all, rocket science.

Hackaday Links: November 8, 2015

[Burt Rutan] is someone who needs no introduction. Apparently, he likes the look of the Icon A5 and is working on his own version.

Earlier this week, the US Air Force lost a few satellites a minute after launch from Barking Sands in Hawaii. This was the first launch of the three stage, solid fueled SPARK rocket, although earlier versions were used to launch nuclear warheads into space. There are some great Army videos for these nuclear explosions in space, by the way.

[Alexandre] is working on an Arduino compatible board that has an integrated GSM module and WiFi chip. It’s called the Red Dragon, and that means he needs some really good board art. The finished product looks good in Eagle, and something we can’t wait to see back from the board house.

The Chippocolypse! Or however you spell it! TI is declaring a lot of chips EOL, and although this includes a lot of op-amps and other analog ephemera (PDF), the hi-fi community is reeling and a lot of people are stocking up on their favorite amplifiers.

[Jeremy] got tired of plugging jumper wires into a breadboard when programming his ATMega8 (including the ‘168 and ‘328) microcontrollers. The solution? A breadboard backpack that fits right over the IC. All the files are available, and the PCB can be found on Upverter.

In case you haven’t heard, we’re having a Super Conference in San Francisco later this week. Adafruit was kind enough to plug our plug for the con on Ask an Engineer last week.

Easy Way To Listen To Cube Sats

[Bill Meara] has discovered an easy way to listen to amateur “cube-sat” satellites using a cheap SDR Dongle.

The DVB-T SDR Dongle comes in at a whopping thirteen bucks, and the highly sophisticated antenna (pdf) is made from a bit of copper wire and uses aluminum wire for the ground plane.

Once he had everything hooked up, [Bill] went to the Heavens Above website to see when satellites would be passing over him. He was able to lock onto the Prism Satellite, and then a couple other cube-sats that were launched from Russia and Istanbul.

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THP Entry: SatNOGS

NOGS Here’s an interesting thought: it’s possible to build a cubesat for perhaps ten thousand dollars, and hitch a ride on a launch for free thanks to a NASA outreach program. Tracking that satellite along its entire orbit would require dozens of ground stations, all equipped with antennas, USB TV tuners, and a connection to the Internet. It’s actually more expensive to build and launch a cubesat than it costs to build a network of ground stations to get reasonably real-time telemetry from a cubesat. The future is awesome and weird, it seems.

This is the observation the guys behind SatNOGS have made. They’re developing a platform for a completely open source ground station network, with the idea being people an institutions along every longitude and latitude would build a simple satellite tracking antenna mount, connect it to the Internet, and become part of an open source Near Space Network, capable of receiving telemetry from any one of the small cubesats whizzing around in low earth orbit.

Despite being what is probably one of the most ambitious and far-reaching projects in open source hardware, the design of the system is relatively simple: the hardware is a 3D printed alt-az mount, capable of pointing a pair of antennas anywhere in the sky. The stepper motor driver board is based on the Arduino, and the computer running each antenna node is powered by a BeagleBone Black or a WR703N router. The antenna receiver is, of course, an RTL-SDR dongle, capable of listening to all the common cubesat bands. Even the software is derived from open source projects. Tracking a satellite across the sky can be calculated with GPredict, and the team is working on an observation scheduling and management system that combines multiple ground stations for coverage across the globe.

It’s a great idea, crowdsourcing satellite tracking from people around the globe, and something that could be used by hundreds of institutions lucky enough to launch a small cube of electronics into orbit.


SpaceWrencherThe project featured in this post is an entry in The Hackaday Prize. Build something awesome and win a trip to space or hundreds of other prizes.

PocketQubes: Even Smaller Than a CubeSat

Qube

Over one hundred CubeSats have been launched by hundreds of organizations and universities from around the globe. These have proven very useful in technology demonstration, Earth imaging, and other applications. There is, however, one large downside to the CubeSat platform. Even though it is designed to hitch a ride on launches of larger satellites, they’re still very expensive to develop and launch – somewhere between $60,000 and $125,000.

PocketQubes are a new design of satellite that bring the cost of personal satellites down to what Universities and amateur radio enthusiasts can actually afford. Instead of spending $125k on a 10cm cube CubeSat, the PocketQube, a 5cm cube, can be launched to a 700 km orbit for about $20,000.

Already, four PocketQubes are scheduled for launch in November to a 700km solar synchronous orbit, including $50SAT, a small radio transceiver put together by some ham guys, and The WREN a very impressive PocketQube with 3-axis reaction wheels and plasma thrusters.

Right now, the PocketQube kickstarter is only for aluminum structures that will become the skeleton of a small, 5cm cube satellite. There’s also the PocketQube Shop that provides a little more background on the project.