Starlink

44 Articles

Detect Starlink Satellites Passing By

November 29, 2021 by 16 Comments

The Starlink beta has semi-officially ended, but it seems as though the global chip shortage is still limiting how many satellites are flying around the world for broadband internet access for those that might not be served by traditional ISPs. Not every location around the world has coverage even if you can get signed up, so to check that status the hard way you can always build a special antenna that tracks the Starlink beacons as they pass overhead.

[Derek] is using this project to show of some of his software-defined radio skills, so this will require an SDR that can receive in the 1600 MHz range. It also requires a power injector to power the satellite receiver, but these are common enough since they are used to power TV antennas. The signals coming from the Starlink satellites have a very high signal-to-noise ratio so [Derek] didn’t even need a dish to focus the signals. This also helped because the antenna he is using was able to see a much wider area as a result. Once everything was set up and the computer was monitoring the correct location in the spectrum, he was able to see very clearly how often a satellite passed him by.

Of course, [Derek] lives in an area with excellent coverage so this might be a little more difficult for those in rural areas, but possibly not for long as the goal of Starlink is to bring broadband to people who otherwise wouldn’t have access to it. There is some issue with how much these satellites might interfere with other astronomical activities though, so take that with a grain of salt.

Thanks to [Spritle] for the tip!

Christian Hahn Starlink capture showing guard region.

Analyzing Starlink Satellite Downlink Communications With Software Defined Radio

November 26, 2021 by 23 Comments

Often, mere curiosity is sufficient to do something. This is also the case with people trying to analyze the communication setup and protocol which SpaceX is using with their Ku-band based Starlink satellites.  One of these fine folk is [Christian Hahn], who has recently posted some early findings to r/StarlinkEngineering over at Reddit. Some of the captured data seems to include the satellite ID system that ground-based user stations would presumably use to keep track of overhead Starlink satellites.

For the capturing itself, [Christian] is using a second-hand dish for capture and a DIY SDR using KC705 FPGA-based hardware – which may have begun its life as crypto mining hardware – along with the usual assortment of filters and other common components with this kind of capture. Even at this early time, some features of the Starlink protocol seem quite obvious, such as the division into channels and the use of guard periods. Nothing too earth-shattering, but as a fun SDR hobby it definitely checks all the boxes.

[Christian] has also announced that at some point he’ll set up a website and publish the findings and code that should make Starlink signal analysis easy for anyone with a readily available SDR receiver.

 

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Hackaday Links: November 7, 2021

November 7, 2021 by 3 Comments

More trouble for Hubble this week as the space observatory’s scientific instruments package entered safe mode again. The problems started back on October 25, when the Scientific Instrument Command and Data Handling Unit, or SI C&DH, detect a lack of synchronization messages from the scientific instruments — basically, the cameras and spectrometers that sit at the focus of the telescope. The issue appears to be different from the “payload computer glitch” that was so widely reported back in the summer, but does seem to involve hardware on the SI C&DH. Mission controller took an interesting approach to diagnosing the problem: the dusted off the NICMOS, or Near Infrared Camera and Multi-Object Spectrometer, an instrument that hasn’t been used since 1998. Putting NICMOS back into the loop allowed them to test for loss of synchronization messages without risking the other active instruments. In true hacker fashion, it looks like the fix will be to change the software to deal with the loss of sync messages. We’ll keep you posted.

What happened to the good old days, when truck hijackings were for things like cigarettes and booze? Now it’s graphics cards, at least according to a forum post that announced the theft of a shipment of EVGA GeForce RTX 30-series graphics cards from a delivery truck. The truck was moving the cards from San Francisco to the company’s southern California distribution center. No word as to the modus operandi of the thieves, so it’s not clear if the whole truck was stolen or if the cards “fell off the back.” Either way, EVGA took pains to note that receiving stolen goods is a crime under California law, and that warranties for the stolen cards will not be honored. Given the purpose these cards will likely be used for, we doubt that either of these facts matters much to the thieves.

Remember “Jet Pack Man”? We sure do, from a series of reports by pilots approaching Los Angeles International airport stretching back into 2020 and popping up occasionally. The reports were all similar — an object approximately the size and shape of a human, floating aloft near LAX. Sightings persisted, investigations were launched, but nobody appeared to know where Jet Pack Man came from or what he was flying. But now it appears that the Los Angeles Police may have identified the culprit: one Jack Skellington, whose street name is the Pumpkin King. Or at least a helium balloon version of the gangly creature, which is sure what an LAPD helicopter seems to have captured on video. But color us skeptical here; after all, they spotted the Halloween-themed balloon around the holiday, and it’s pretty easy to imagine that the hapless hero of Halloween Town floated away from someone’s front porch. More to the point, video that was captured at the end of 2020 doesn’t look anything like a Skellington balloon. So much for “case closed.”

Speaking of balloons, here’s perhaps a more productive use for them — lifting a solar observatory up above most of the atmosphere. The Sunrise Solar Observatory is designed to be lifted to about 37 km by a balloon, far enough above the Earth’s ozone layer to allow detailed observation of the Sun’s corona and lower atmosphere down into the UV range of the spectrum. Sunrise has already flown two successful missions in 2009 and 2013 which have netted over 100 scientific papers. The telescope has a one-meter aperture and automatic alignment and stabilization systems to keep it pointed the right way. Sunrise III is scheduled to launch in June 2022, and aims to study the flow of material in the solar atmosphere with an eye to understanding the nature of the Sun’s magnetic field.

And finally, what a difference a few feet can make. Some future Starlink customers are fuming after updating the location on their request for service, only to find the estimated delivery date pushed back a couple of years. Signing up for Starlink satellite service entails dropping a pin on a map to indicate your intended service location, but when Starlink put a new, more precise mapping app on the site, some eager pre-order customers updated their location to more accurately reflect where the dish will be installed. It’s not clear if the actual location of the dish is causing the change in the delivery date, or if just the act of updating an order places you at the bottom of the queue. But the lesson here may be that with geolocation, close enough is close enough.

GPS? With Starlink, We Don’t Need It Any More!

October 10, 2021 by 58 Comments

To find your position on the earth’s surface there are a variety of satellite-based navigation systems in orbit above us, and many receiver chipsets found in mobile phones and the like can use more than one of them. Should you not wish to be tied to a system produced by a national government though, there’s now an alternative. It comes not from an official source though, but as a side-effect of something else. Researchers at Ohio State University have used the Starlink satellite broadband constellation to derive positional fixing, achieving a claimed 8-metre accuracy.

The press release is light on information about the algorithm used, but since it mentions that it relies on having advance knowledge of the position and speed of each satellite we’re guessing that it measures the Doppler shift of each satellite’s signal during a pass to determine a relative position which can be refined by subsequent observations of other Starlink craft.

The most interesting takeaway is that while this technique leverages the Starlink network, it doesn’t have any connection to the service itself. Instead it’s an entirely passive use of the satellites, and though its accuracy is around an order of magnitude less than that achievable under GPS it delivers a position fix still useful enough to fit the purposes of plenty of users.

Earlier in the year there was some amusement when the British government bought a satellite broadband company under the reported impression it could plug the gap left by their withdrawal from the European Galileo project. Given this revelation, maybe they were onto something after all!

Thanks [Renze] for the tip.

StarLink Terminal Unit Firmware Dumped

July 7, 2021 by 17 Comments

There’s a lot of expense in what telephone companies call “the last mile” — delivering service from the main trunks to your home or business. StarLink wants to avoid that cost by connecting you via an array of low-orbit satellites and some users are already using the service. In Belgium, [Lennert Wouters] managed to dump the terminal’s firmware and has some interesting observations.

The teardown is actually more than just a firmware dump. His “level 1” teardown involves exposing the board. This can be tricky because there are apparently different versions of the terminal out already, so advice from one source might not match your hardware, and that was the case here.

Continue reading “StarLink Terminal Unit Firmware Dumped” →

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Hackaday Links: July 4, 2021

July 4, 2021 by 9 Comments

With rescue and recovery efforts at the horrific condo collapse in Florida this week still underway, we noted with interest some of the technology being employed on the site. Chief among these was a contribution of the Israeli Defense Force (IDF), whose secretive Unit 9900 unveiled a 3D imaging system to help locate victims trapped in the rubble. The pictures look very much like the 3D “extrusions” that show up on Google Maps when you zoom into a satellite view and change the angle, but they were obviously built up from very recent aerial or satellite photos that show the damage to the building. The idea is to map where parts of the building — and unfortunately, the building’s occupants — ended up in the rubble pile, allowing responders to concentrate their efforts on the areas most likely to hold victims. The technology, which was developed for precision targeting of military targets, has apparently already located several voids in the debris that weren’t obvious to rescue teams. Here’s hoping that the system pays off, and that we get to learn a little about how it works.

Radio enthusiasts, take note: your hobby may just run you afoul of authorities if you’re not careful. That seems to be the case for one Stanislav Stetsenko, a resident of Crimea who was arrested on suspicion of treason this week. Video of the arrest was posted which shows the equipment Stetsenko allegedly used to track Russian military aircraft on behalf of Ukraine: several SDR dongles, a very dusty laptop running Airspy SDR#, an ICOM IC-R6 portable communications receiver, and various maps and charts. In short, it pretty much looks like what I can see on my own desk right now. We know little of the politics around this, but it does give one pause to consider how non-technical people view those with technical hobbies.

If you could choose a superpower to suddenly have, it really would take some careful consideration. Sure, it would be handy to shoot spider webs or burst into flames, but the whole idea of some kind of goo shooting out of your wrists seems gross, and what a nuisance to have to keep buying new clothes after every burn. Maybe just teaching yourself a new sense, like echolocation, would be a better place to start. And as it turns out, it’s not only possible for humans to echolocate, but it’s actually not that hard to learn. Researchers used a group of blind and sighted people for the test, ranging in age from 21 to 79 years, and put them through a 10-week training program to learn click-based echolocation. After getting the basics of making the clicks and listening for the returns in an anechoic chamber, participants ran through a series of tasks, like size and orientation discrimination of objects, and virtual navigation. The newly minted echolocators were also allowed out into the real world to test their skills. Three months after the study, the blind participants had mostly retained their new skill, and most of them were still using it and reported that it had improved their quality of life.

As with everything else he’s involved with, Elon Musk has drawn a lot of criticism for his Starlink satellite-based internet service. The growing constellation of satellites bothers astronomers, terrestrial ISPs are worried the service will kill their business model, and the beta version of the Starlink dish has been shown to be flakey in the summer heat. But it’s on equipment cost where Musk has taken the most flak, which seems unfair as the teardowns we’ve seen clearly show that the phased-array antenna in the Starlink dish is being sold for less than it costs to build. But still, Musk is assuring the world that Starlink home terminals will get down in the $250 to $300 range soon, and that the system could have 500,000 users within a year. There were a couple of other interesting insights, such as where Musk sees Starlink relative to 5G, and how he’s positioning Starlink to provide backhaul services to cellular companies.

Well, this is embarrassing. Last week, we mentioned that certain unlucky users of an obsolete but still popular NAS device found that their data had disappeared, apparently due to malefactors accessing the device over the internet and forcing a factory reset. Since this seems like something that should require entering a password, someone took a look at the PHP script for the factory restore function and found that a developer had commented out the very lines that would have performed the authentication:

    function get($urlPath, $queryParams=null, $ouputFormat='xml'){
//        if(!authenticateAsOwner($queryParams))
//        {
//            header("HTTP/1.0 401 Unauthorized");
//            return;
//        }

It’s not clear when the PHP script was updated, but support for MyBook Live was dropped in 2015, so this could have been a really old change. Still, it was all the hacker needed to get in and wreak havoc; interestingly, the latest attack may be a reaction to a three-year-old exploit that turned many of these devices into a botnet. Could this be a case of hacker vs. hacker?

Not All SpaceX Software Goes To Space

June 1, 2021 by 13 Comments

SpaceX has always been willing to break from aerospace tradition if they feel there’s a more pragmatic solution. Today this is most visible in their use of standard construction equipment like cranes in their Starship development facility. But the same focus on problem solving can also be found in their software parts we don’t see. Recently we got two different views behind the scenes. First, a four-part series about “software in space” published by StackOverflow blog, followed quickly by an Ask Me Anything (AMA) session on SpaceX Reddit.

Some of the StackOverflow series cover ground that has been previously discussed. Mostly in the first part dealing with their workhorse Falcon and Dragon vehicles, and some in the second part discussing Starlink whose beta program is reaching more and more people. Both confirmed that spaceflight software has to meet very stringent requirements and are mostly close to the metal bespoke C++ code. But we receive fascinating new information in part three, which focuses on code verification and testing. Here they leverage a lot of open source infrastructure more common to software startups than aerospace companies. The fourth and final component of this series covers software to support SpaceX hardware manufacturing, which had been rarely discussed before this point. (Unfortunately, there was nothing about how often SpaceX software developers copy and paste code from StackOverflow.)

The recent Reddit AMA likewise had some overlap with the SpaceX software AMA a year ago, but there were new information about SpaceX work within the past year. There was Crew Dragon’s transition from a test to an operational vehicle, and the aforementioned Starship development program. Our comments section had a lot of discussion about the practicality of touchscreen interfaces in real spacecraft, and here we learn SpaceX put a lot of study into building something functional and effective.

It also showed us that essentially every Sci-Fi Movie Interface was unrealistic and would be unreadable under extreme conditions.

In the course of this research, they learned a lot of pitfalls about fictional touch interfaces. Though to be fair, movie and television spacecraft UI are more concerned about looking cool than being useful.

If the standard AMA format is not to your liking, one of the contributors compiled all SpaceX answers alongside their related questions in a much more readable form here. And even though there’s an obvious recruiting side to these events, we’re happy to learn more about how SpaceX have continued to focus on getting the job done instead of rigidly conforming to aerospace tradition. An attitude that goes all the way back to the beginning of this company.