Life At JPL Hack Chat

Join us on Wednesday, August 21st at noon Pacific for the Life at JPL Hack Chat with Arko!

There’s a reason why people use “rocket science” as a metaphor for things that are hard to do. Getting stuff from here to there when there is a billion miles away and across a hostile environment of freezing cold, searing heat, and pelting radiation isn’t something that’s easily accomplished. It takes a dedicated team of scientists and engineers working on machines that can reach out into the vastness of space and work flawlessly the whole time, and as much practice and testing as an Earth-based simulation can provide.

Arko, also known as Ara Kourchians, is a Robotics Electrical Engineer at the Jet Propulsion Laboratory, one of NASA’s research and development centers. Nestled at the outskirts of Pasadena against the flanks of the San Gabriel Mountains, JPL is the birthplace of the nation’s first satellite as well as the first successful interplanetary probe. They build the robots that explore the solar system and beyond for us; Arko gets to work on those space robots every day, and that might just be the coolest job in the world.

Join us on the Hack Chat to get your chance to ask all those burning questions you have about working at JPL. What’s it like to build hardware that will leave this world and travel to another? Get the inside story on how NASA designs and tests systems for space travel. And perhaps get a glimpse at what being a rocket scientist is all about.

join-hack-chatOur Hack Chats are live community events in the Hack Chat group messaging. This week we’ll be sitting down on Wednesday, August 21 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

Spain’s First Open Source Satellite

[Fossa Systems], a non-profit youth association based out of Madrid, is developing an open-source satellite set to launch in October 2019. The FossaSat-1 is sized at 5x5x5 cm, weighs 250g, and will provide free IoT connectivity by communicating LoRa RTTY signals through low-power RF-based LoRa modules. The satellite is powered by 28% efficient gallium arsenide TrisolX triple junction solar cells.

The satellite’s development and launch cost under EUR 30000, which is pretty remarkable for a cubesat — or a picosatellite, as the project is being dubbed. It has been working in the UHF Amateur Satellite band (435-438 MHz) and recently received an IARU frequency spectrum allocation for LoRa of 125kHz.

The satellite’s specs are almost as remarkable as the acronyms used to describe them. The design includes an onboard computer (OBC) based on an ATmega328P-AU microcontroller, an SX1278 transceiver for telecommunications, and an electric power system (EPS) based on three SPV1040 MPPT chips and the TC1262 LDO. The satellite also uses a TMP100 temperature sensor, an INA226 current and voltage sensor, a MAX6369 watchdog for single-event upset (SEU) protection, a TPS2553 for single-event latch-up (SEL) protection and various MOSFETs for the deployment of solar panels and antennas.

Up until this point the group has been tracking adoption of LoRa through the use of weather balloons. The cubesat project plans to test the new LoRa spread spectrum modulation using less than $5 worth of receivers. Ultimately with the goal of democratizing telecommunications worldwide.

The satellite is being built in a cleanroom at Rey Juan Carlos University and has undergone thermovacuum and vibration testing at the facility. The group has since developed an educational satellite development kit, which offers three main 40×40 mm boards that allow the addition of modifications. As their mission states, the group is looking to develop an open source project, so the code for the satellite is freely available on their GitHub.

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The Death Of A Weather Satellite As Seen By SDR

What is this world coming to when a weather satellite that was designed for a two-year mission starts to fail 21 years after launch? I mean, really — where’s the pride these days?

All kidding aside, it seems like NOAA-15, a satellite launched in 1998 to monitor surface temperatures and other meteorologic and climatologic parameters, has recently started showing its age. This is the way of things, and generally the decommissioning of a satellite is of little note to the general public, except possibly when it deorbits in a spectacular but brief display across the sky.

But NOAA-15 and her sister satellites have a keen following among a community of enthusiasts who spend their time teasing signals from them as they whiz overhead, using homemade antennas and cheap SDR receivers. It was these hobbyists who were among the first to notice NOAA-15’s woes, and over the past weeks they’ve been busy alternately lamenting and celebrating as the satellite’s signals come and go. Their on-again, off-again romance with the satellite is worth a look, as is the what exactly is going wrong with this bird in the first place.

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L Band Satellite Antennas Revealed

[SignalsEverywhere] has a lot of satellite antennas and he’s willing to show them off — inside and out — in his latest video that you can see below. Using software-defined radio techniques, you can use these antennas to pull off weather satellite images and other space signals.

A lot of these antennas are actually made for some commercial purpose like keeping ships connected to Inmarsat. In fact, the shipborne antenna has a nice motorized system for pointing the antenna that [SignalsEverywhere] is hoping to modify for his own purposes.

With what appears to be standard NEMA 17 steppers onboard, it should be relatively easy to supplant the original controller with an Arduino and CNC shield. Though considering the resale value these particular units seem to have on eBay, we might be inclined to just roll our own positioner.

The QHF QFH antenna is another interesting teardown. The antenna makes a helix shape and looks like it would be interesting to build from scratch. There isn’t a lot of details about the antenna designs, but it is interesting to see the variety and range of antennas and how they appear internally.

L band is from 1 GHz to 2 GHz, so signals and antennas get very strange at these frequencies. The wavelength of a 2GHz signal is only 15cm, so small antennas can work quite well and are often as much mechanical designs as electrical. The L band contains everything from GPS to phone calls to ADS-B.

We’ve seen radiosonde antennas reborn before. Dish antenna repurposing is also popular.

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How To Build A CubeSat

There was a time when building your own satellite and having it placed into orbit would have been a wild dream. Now it is extremely possible, but still not trivial. A CubeSat is a very small satellite that can hitch a ride with a bigger satellite or get tossed out of a friendly space station. This week’s issue of The Orbital Index has a very good overview of what all is required. It also contains a great selection of links to get more information.

At first glance, it seems like it would be pretty simple. A computer, a battery, and some solar cells. Well, you probably want to hear back from it, so then you need a radio. Oh, and an antenna. But the antenna can’t stick out during launch so you need a way to deploy it. If you want the satellite to point somewhere, you’ll need things for that, too. Some CubeSats even have tiny thrusters to affect their orbit.

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Retrotechtacular: The OSCAR 7 Satellite Died And Was Reborn 20 Years Later

If I were to ask you what is the oldest man-made orbiting satellite still in use, I’d expect to hear a variety of answers. Space geeks might mention the passive radar calibration spheres, or possibly one of the early weather satellites. But what about the oldest communication satellite still in use?

The answer is a complicated one. Oscar 7 is an amateur radio satellite launched on November 5th 1974, carrying two transponders and four beacons, all of which operate on bands available to amateur radio operators. Nearly 45 years later it still provides radio amateurs with contacts just as it did in the 1970s. But this bird’s history is anything but ordinary. It’s the satellite that came back from the dead after being thought lost forever. And just as it was fading from view it played an unexpected role in the resistance to the communist government in Poland.

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Inside The Mysterious Global Navigation Outage You Probably Didn’t Notice

The entire world has come to depend on satellite navigation systems in the forty or so years since the first Global Positioning System satellites took to orbit. Modern economies have been built on the presumption that people and assets can be located to within a meter or better anywhere on, above, or even slightly under the surface of the planet. For years, GPS was the only way to do that, but billions have been sunk into fielding other global navigation systems, achieving a measure of independence from GPS and to putting in place some badly needed redundancy in case of outages, like that suffered by the European Union’s Galileo system recently.

The problem with Galileo, the high-accuracy public access location system that’s optimized for higher latitudes, seems to be resolved as of this writing. The EU has been tight-lipped about the outage, however, leaving investigation into its root cause to a few clever hackers armed with SDRs and comprehensive knowledge of exactly how a constellation of satellites can use the principles of both general and special relativity to point you to your nearest Starbucks.

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