Tagged: satellite

Decoding the Lucky-7 Cubesat

Lucky-7 is a Czech cubesat that carries some interesting sensors including a low power GPS receiver, a gamma ray spectrometer and dosimeter and a photo camera. The creators also claim that it is "probably the lowest-cost scientific space mission in human history". It was recently successfully launched and orbited together with the Meteor M2-2 weather satellite and several other small satellites.

"We did not build just another satellite. It is a flying laboratory. The satellite is going to test something that nobody has ever done before. Thanks to our background in electronics, materials and space effects, we implemented commonly used electrical parts from automotive and IoT industry in totally new ways. Gallium Nitride power transistors used in modern electric cars do not contain insulation layer to control its conductivity. That makes them much less vulnerable against the space radiation. We fly the world's first MOSFET-free power supply ever built for small satellites. The LED lighting industry has been used to make composite aluminum radiation shields for us. It is very cheap, lightweight and it naturally increases the mission lifetime," says Jaroslav Laifr, the CEO and founder.

If all goes well, the team will be able to measure the in-situ radiation background by miniature onboard Dosimeter and monitor the health of key subsystems, such as communication or data storage by complete satellite telemetry. The experimental Gamma Spectrometer payload informing about the energy of incident radiation will be able to detect Gamma Ray Bursts from distant galaxies. The platform also contains the VGA camera to demonstrate the data transfer capability. It may capture the first colour images ever taken by Czech satellite, possibly detecting the aurora glow. Such pictures would be greatly utilized for the outreach and inspire a new generation of scientists and engineers.

Daniel Estesvev has recently added a Lucky-7 decoder to gr-satellites, and has uploaded a post explaining some technical details on how he created the decoder. With this decoder, anyone with an SDR and appropriate antenna should be able to receive and decode the telemetry (no word on camera images yet). He writes that "Lucky-7 transmits 4k8 GFSK telemetry in the 70cm band. It uses a SiLabs Si4463 transceiver with a PN9 scrambler and a CRC-16. You must use FM mode to receive this satellite (437.525MHz)."

CubeSat companies like Sky Fox Labs are also tracking the satellite, and are tweeting results.

SignalsEverywhere: Satcom Antennas for L-Band Reception via RTL-SDR + Podcast on the MiTee CubeSat Project

On this episode of SignalsEverywhere on YouTube Corrosive shows off several antennas that can be used for Inmarsat and Iridium satcom reception. His video shows off a commercial Inmarsat branded satlink antenna which is designed to be used on moving ships, a grid dish antenna, a custom QFH iridium antenna made from a repurposed Vaisala radiosonde, a commercial Iridium patch, an older Outernet/Othernet Iridium patch and a custom Iridium patch that Corrosive built himself.

Satcom Antennas for L-Band Reception via RTL SDR

A few days prior Corrosive also released a new episode of his podcast. In this episode he interviewed Derek a student from The University of Michigan who is working on the MiTee CubeSat. The MiTee cubesat is a small experimental satellite that will explore the use of miniaturized electrodynamic tethers for satellite propulsion.

SDR-Makerspace Talk: Evaluation of SDR boards and toolchains

The Software Defined Radio Academy YouTube channel recently uploaded an interesting talk by Alex Csete (creator of the popular GQRX and GPredict applications), and Sheila Christiansen. Their presentation discusses their work with the European Space Agency (ESA), Libre Space Foundation and how they are running SDR Makerspace's that are helping students create and track cubesats. During the talk Alex and Sheila also describe various SDR hardware, and how they test them for their purposes.

SDR Makerspace (https://sdrmaker.space) is a collaboration between the European Space Agency and Libre Space Foundation, with the objective of bringing innovative open-source SDR technologies to space communications.

Space is a complex environment. Attempting to incorporate SDRs into complex subsystems of space missions without sufficient understanding of the technology can add unnecessary risks and uncertainties to the mission. SDR Makerspace aims to bring open-source SDR technology to the space industry, focusing on the practical aspects of satellite communications, so as to reduce such risks.

Makers, open-source hackers, SDR enthusiasts, and researchers are collaborating on SDR hardware and software activities, focusing on rapid prototyping and development of reusable, open-source SDR components for future CubeSat missions.

The collaboration consists of many activities, which are organized into three main elements: development of reusable GNU Radio components, research and development in cutting edge technologies like AI/ML, and testing of SDR hardware and software.

Current activities are presented with a focus on the testing of the hardware and software. An overview of the investigation into the characteristics, such as, performance under realistic conditions, damage by radiation to essential parts, functionality of FPGA toolchains, the SDR-system’s complexity, and accessibility to the open-source community will also be covered.

Alex Csete, OZ9AEC: SDR-Makerspace: Evaluation of SDR boards and toolchains

Investigating the Galileo Satellite Navigation System Outage with a LimeSDR

Galileo is a European Union owned satellite navigation system. Galileo was created so that the EU does not need to rely on the US GPS or the Russian GLONASS satellites, as there is no guarantee that these systems won't be purposely turned off or degraded by their governments at any time.

Unfortunately since July 11 the Galileo system has been out of service. Not much information about the outage has been provided, but it appears to be related to problems with the Italian ground based Precise Timing Facility which consists of two ultra high precision atomic clocks that keep the Galileo systems' reference time. (We note that recently within the last few hours of this post, most satellites seem to have come back into operational status, but the EGSA website still reports an outage.)

Over on his blog, Daniel Estevez has been using his LimeSDR and a small patch antenna to gather some more information about the outage directly from the Galileo satellites. His investigations found that the modulation and signal itself are still working correctly. However, by using the GNSS-SDR software to investigate the signal data he was able to obtain the ephemeris, and see that the ephemeris is stuck in the past. The ephemeris data is used to calculate compensations for orbital drift and without frequent ephermis updates, orbital errors add up within hours resulting in poor positioning accuracy. In order to generate the ephermis, the Precise Timing Facility must be operational.

Daniel's post goes into further technical details about the information he's collected, and it's definitely an interesting read. One interesting bit of information that you can read from his post explains why the service has gone from initially just heavily degraded accuracy from July 11, to completely nonsense results from July 15 onwards.

Meteor M N2-2 Successfully Launched: Awaiting LRPT Signal

On July 5 the Russian Meteor M N2-2 weather satellite was successfully launched into orbit and appears to be healthy. The LRPT weather camera signal is not yet broadcasting however, and we expect it to still take roughly 1-2 months before it begins (if all goes well) as satellites typically run through a long list of qualification tests before becoming operational. During this time there may be broadcasts of test patterns that can be caught. Meteor M N2-2 can currently be tracked in Orbitron and online at N2YO.

To try and dispel any confusion over the naming scheme, "Meteor M N2" is the currently operational LRPT satellite. "Meteor M N2-1" unfortunately failed in 2017 as it did not separate from the rocket. "Meteor M N2-2" is the new satellite which has just been successfully launched. Meteor M N2 and M N2-2 is often abbreviated as just "Meteor M2" and "Meteor M2-2". In the past there was Meteor M N1, but this satellite is no longer operational. We have upcoming launches for Meteor M2-3, M2-4, MP-1 and M3 to look forward to which are scheduled for 2020 and 2021.

Back on June 28 we posted about how Meteor M2 was experiencing orientation issues for a few days. Those issues appear to have been rectified now. Hopefully if M2 remains stable we'll have two Meteor LRPT weather satellites to receive alongside the three NOAA APT satellites.

If you're interested, there were also several other payloads onboard the rocket carrying M2-2, including a low cost Czech experimental cubesat called Lucky7 whose telemetry can be received in the amateur radio band at 437.525 MHz. There is an onboard camera too, but no details on how to receive it yet.

Soyuz Rocket carrying Meteor M2-2 Launched successfully. [Source: spaceflightnow]

Solar Sail Satellite Lightsail-2 Now Transmitting Morse Code Beacon

Lightsail-2 is a solar sail experiment which successfully launched on a Space-X Falcon Heavy on 25 June, and was released into orbit on July 2nd. A solar sail is a type of spacecraft that uses a large metallic foil to create propulsion via photons from the sun hitting it. Lightsail-2 is still undergoing testing, so it has not yet deployed it's solar sail, but recent updates indicate that it is healthy.

On board Lightsail-2 is a radio which is transmitting it's morse code beacon "WM9XPA" every 45 seconds at 437.025 MHz. This beacon should be able to be received with a handheld amateur radio 70cm Yagi and any radio such as an RTL-SDR. There is also an AX.25 telemetry data transmission, however although the beacon structure is available we are not aware of any publicly available decoding software.

One difficulty in receiving Lightsail-2 is that it is in an orbit inclination of only 24 degrees. So only locations with a latitude between 42 and -42 degrees will have a chance at receiving it. You can see the solar sail's current location at N2YO. Clicking on the 10-day predictions button will give you pass predictions for your location.

Estimated Lightsail-2 Viewing Range
Estimated Lightsail-2 Viewing Range
Lightsail-2 Deployed
Lightsail-2 Deployed

SignalsEverywhere: Investigating USGS Gaging Stations and their GOES Satellite Connection

The United States Geological Service maintains over 8500 "Gaging stations" in bodies of water all over the country. Gaging stations are devices that are used to measure environmental data such as groundwater levels, discharge, water chemistry, and water temperature. What's interesting is that they all upload their data in real time to GOES satellites - the same satellites that we can use with an RTL-SDR to receive weather images of the entire earth. The data is then downlinked in the L-band to the USGS scientists via a protocol known as DCP (Data Collection Platform).

In the latest SignalsEverywhere video, Corrosive investigates how these stations work, and how we can receive the downlink at 1.68 GHz with a simple Inmarsat L-band antenna. While a fully functional decoder is not yet available, Corrosive notes that one called goes-dcs is currently being worked on.

USGS Gaging Station | Satellite Uplink to GOES and DCP Messages

Meteor M2 is Currently Experiencing Orientation Issues

Russian weather satellite Meteor M2 is a popular reception target for RTL-SDR radio enthusiasts, as it allows you to receive high resolution images of the Earth. However, currently it appears to be exhibiting orientation issues, causing off center and skewed images and sometimes poor/no reception. Russian blog "aboutspacejornal", writes that the orientation of the satellite can sometimes be restored presumably by a reset command from Earth, but shortly after goes back into uncontrolled rotation.

These sorts of off-axis images were commonly received from the older decommissioned Meteor-M1 satellite, which woke up from the dead in 2015. The resurrection was speculated to be from the batteries shorting out, allowing power to directly flow from the solar panels while in full sunlight. These days Meteor-M1 is no longer transmitting.

Meteor M2 proving the curvature of the earth due to it's orientation issues.
Meteor M2 proving the curvature of the earth due to it's orientation issues.  Image source aboutspacejornal.

Hopefully Meteor-M2 can be fixed, but if not, Meteor M2-2 is due to be launched on July 5 which should also have an LRPT signal that can be received easily with an RTL-SDR. Hopefully the launch is more successful than the November 2017 launch of Meteor M2-1 which unfortunately was a complete loss as it failed to separate from the rocket.