SDR: Satellite Death Receiver

November 4, 2014 by Kristina Panos 18 Comments

Halloween may be over, but [happysat] has found a way to listen to the dead. Satellites, that is, specifically those in the 136-138 MHz and 150-400 MHz ranges. He’s using an RTL-SDR dongle and a QFH antenna to detect the death throes of decommissioned navigation and space research satellites.

[happysat] was listening to NOAA/Meteor on the 137MHz band when he made this discovery. When a satellite is near end of life, the last bit of fuel is used to push it into graveyard orbit. This doesn’t always work, however, and when the light is just right, a chemical reaction makes the long-dead batteries conduct and these satellites in purgatory transmit once more.

They’re not sending out anything ~~proprietary~~ useful, just unmodulated carrier that sometimes interferes with currently operational satellites on the 136-138 MHz band. [happysat] captured some audio from two of the oldest satellites that are still broadcasting, and links to a TLE set of dead satellites he created. Check out his frequency database for SDR# as well. Don’t have a weather satellite-capable antenna? Build one!

[via /r/RTLSDR]

THP Entry: SatNOGS

June 13, 2014 by Brian Benchoff 10 Comments

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.

The 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.

ISEE-3: Ready To Come Home

May 16, 2014 by Brian Benchoff 31 Comments

The team working to reboot the ISEE-3 satellite hurtling towards an August encounter with Earth is hard at work. They’ve put up a crowdfunding page, and now that they’re completely funded (don’t stop donating, btw), they’re starting to go deeper into the waters that will allow them to capture a forgotten satellite.

The project put up a status report going over what they’ve accomplished so far, and what work has yet to be done. For a few months now, they knew both transmitters aboard the craft were operational, but they were not sending telemetry. The team has gone through the documentation, came up with a set of commands, and are currently en route to Arecibo to transmit those commands.

Two ground station transmitters are being constructed, one specifically built to be installed at Arecibo for this application. The other is a portable, self-contained 700 watt transmitter that will be used at the official ISEE-3 ground station in Morehead State University in Kentucky.

With transmitters taken care of and receiving handled by an SDR from Ettus Research, a lot of work has focused on the command and telemetry systems. In 1978, the user interface for commands and telemetry was primitive to say the least. The team is now working on a system built-in Labview that’s much easier on the eyes than the vintage text terminal screens.

So far, signals from ISEE-3 are planned to be received at Arecibo, Morehead State, and Bochum observatory in Germany. This will give the team extremely good coverage for most of a day, and there are other ground stations in California that will extend the time the team is able to communicate with ISSE-3 each day by a few hours.

There’s still a lot of work to be done; the team really doesn’t know what systems are still operating, although most of them did make it 20 years with only one fault. In the next few days, we’ll all get to see if this satellite will be up to the task of coming back home to Earth. If everything goes to plan, ISEE-3 will be on track towards a 17 hour burn to put it on the correct trajectory some time in mid June.

Listening To A Swarm Of Satellites In Orbit

May 4, 2014 by Brian Benchoff 36 Comments

kicksat

A few months ago, we heard of a Kickstarter with an amazing goal: give everyone with $300 burning a hole in their pocket their very own satellite orbiting Earth. Time passes, the mothership has been launched, and in just a few short hours, over a hundred of these personal femtosatellites will be released into low Earth orbit.

The Kicksat consists of a 3U cubesat that was recently launched aboard the SpaceX CRS-3 mission to the International Space Station. Inside this cubesat are over one hundred satellites called Sprites, loaded up with solar cells, magnetometers, a microcontroller and a radio to communicate with ground stations below. The current mission is a proof of concept, but if everything goes as planned, similar satellites can be deployed into the path of incoming asteroids, or whenever a mission calls for a swarm of small smart devices covering a huge area.

Already the Kicksat mothership has been tracked by a few enterprising amateur radio enthusiasts but the deployment of the Sprites isn’t scheduled until today at 4:00 PM EDT (20:00 GMT). After that, the Sprites will be on their own, spewing out data and the initials of kickstarter backers to most of the population of Earth.

For anyone worrying about these Sprites causing an ablation cascade or a Kessler syndrome, don’t. Orbital decay is a function of surface area and mass, and these extremely lightweight thin rectangles will burn up in the atmosphere in a few week’s time. The lack of radiation hardening on the Sprites won’t be a problem, either. This shouldn’t be a surprise, as they’re orbiting well within our wonderful, protective magnetosphere, and there are digital cameras, tablets, and other much more radiation sensitive electronics that have been working perfectly on the ISS for years now.

You can check out the current location of the orbiting Kicksat mothership on the project website, read the updates on the project blog, or check out our coverage of the Kicksat program from last year’s world maker faire in New York. Relevant videos below.

Oh, and if you have a USB TV tuner, a good antenna, LNA, and some experience with SDR, here’s what you need to listen in.

Continue reading “Listening To A Swarm Of Satellites In Orbit” →

Sending Open-Source Satellites To Space

May 1, 2014 by Mathieu Stephan 12 Comments

An anonymous reader tipped us about two Argentinian satellites (satellite one, satellite two) that were sent in 2013 to space. What is interesting about them? They are both based on commercial off-the-shelf (COTS) components, and the team released the framework & flight computer software for their main platform (named cubesat, GitHub link). Gunter’s space page not only impresses us by showing the quantity of small/amateur satellites sent each month to space, but also lets us know that the hardware source files for CudeBug 1/2 are meant to be released. In the meantime we can only gather that they’re using a Texas Instruments TMS570 running FreeRTOS. Nevertheless, the two different web pages (in spanish and english) offer us a very interesting glimpse of what it takes to send an electronic project to space and how it later behaves.

You may also be interested in checking out ArduSat, a successful kickstarter campaign aimed at sending Arduino experiments in space.

PocketQubes: Even Smaller Than A CubeSat

October 2, 2013 by Brian Benchoff 24 Comments

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.

Pocket Sized Sattelites For Asteroid Detection

September 21, 2013 by Brian Benchoff 34 Comments

satellite

We’ve seen kicksats before, small pocketable single board satellites designed to orbit Earth. At this year’s Maker Faire, the team behind these kicksats has a new plan: using them to determine the orbits of earth-passing asteroids and hopefully not giving us any forewarning of our imminent extinction.

Instead of simply orbiting Earth, the new plan for these kicksats is to deploy them into the path of an oncoming asteroid such as Apophis so the radio transmissions from each satellite can pinpoint where exactly the asteroid is, something Earthbound optical and radio telescopes struggle with.

Despite the small size, the hardware on each kicksat is pretty impressive; each mini satellite has a solar cell on each side, a low-power MSP430 microcontroller with a radio module, and a few sensors. The system is designed so anyone can pick up the telemetry from these satellites with a small Yagi antenna and an RTL SDR TV tuner dongle.

An impressive bit of kit, but if holding a satellite or asteroid in your hand is more your thing, the same team behind the kicksat put up a whole bunch of 3D models of asteroids and space probes. They’re actually quite impressive when they’re printed out.