The International Space Station, or ISS, has been in orbit in its various forms now for almost twenty years. During that time many of us will have stood outside on a clear night and seen it pass overhead, as the largest man-made object in space it is clearly visible without a telescope.
Most ISS-watchers will know that the station carries a number of amateur radio payloads. There are voice contacts when for example astronauts talk to schools, there are digital modes, and sometimes as is happening at the moment for passes within range of Moscow (on Feb. 14, 11:25-16:30 UTC) the station transmits slow scan television, or SSTV.
You might think that receiving SSTV would be hard work and require expensive equipment, but given the advent of ubiquitous mobile and tablet computing alongside dirt-cheap RTL-SDRs it is now surprisingly accessible. An Android phone can run the SDRTouch software defined radio app as well as the Robot36 SSTV decoder, and given a suitable antenna the pictures can be received and decoded relatively easily. The radio must receive 145.8MHz wideband FM and the decoder must be set to the PD120 PD180 mode (Thanks [M5AKA] for the update), and here at least the apps are run on separate Android devices. It is possible to receive the signal using extremely basic antennas, but for best results something with a little gain should be used. The antenna of choice here is a handheld [HB9CV] 2-element beam.
You can find when the station is due to pass over you from any of a number of ISS tracker sites, and you can keep up to date with ISS SSTV activity on the ARISS news page. Then all you have to do is stand out in the open with your receiver and computing devices running and ready, and point your antenna at the position of the station as it passes over. If you are lucky you’ll hear the tones of the SSTV transmission and a picture will be decoded, if not you may receive a garbled mess. Fortunately grabs of other people’s received pictures are posted online, so you can take a look at what you missed if you don’t quite succeed.
Even if you don’t live within range of a pass, it’s always worth seeing if a Web SDR somewhere is in range. For example this Russian one for the current transmissions.
In that you are using off-the-shelf hardware and software you might complain there is little in the way of an elite hack about pulling in a picture from the ISS. But wait a minute — you just received a picture from an orbiting space station. Do that in front of a kid, and see their interest in technology come alive!
Whether it’s trying to make contacts across the planet with a transmitter that would have a hard time lighting an LED, or blasting signals into space and bouncing them off the moon, amateur radio operators have always been on the forefront of communications technology. As mankind took to space in the 1950s and 1960s, hams went along for the ride with the first private satellites. But as successful as the OSCAR satellites were, they were still at best only beacons or repeaters in space. What was needed was the human touch – a real live operator making contacts with people on the ground, showing the capabilities of amateur radio while generating public interest in the space program. What was needed was a ham in space. Continue reading “Hams In Space Part 2: The Manned Spaceflights”→
When Hackaday announced winners of the 2014 Hackaday Prize, a bunch of hackers from Greece picked up the grand prize of $196,418 for their SatNOGS project – a global network of satellite ground stations for amateur Cubesats.
The design demonstrated an affordable ground station which can be built at low-cost and linked into a public network to leverage the benefits of satellites, even amateur ones. The social implications of this project were far-reaching. Beyond the SatNOGS network itself, this initiative was a template for building other connected device networks that make shared (and open) data a benefit for all. To further the cause, the SatNOGS team set up the Libre Space Foundation, a not-for-profit foundation with a mission to promote, advance and develop Libre (free and open source) technologies and knowledge for space.
Now, the foundation, in collaboration with the University of Patras, is ready to launch UPSat – a 2U, Open Source Greek Cubesat format satellite as part of the QB50 international thermosphere research mission. The design aims to be maximally DIY, designing most subsystems from scratch. While expensive for the first prototype, they hope that documenting the open source hardware and software will help kickstart an ecosystem for space engineering and technologies. As of now, the satellite is fully built and undergoing testing and integration. In the middle of July, it will be delivered to Nanoracks to be carried on a SpaceX Dragon capsule and then launched from the International Space Station.
The shocking thing is not that this happened. The shocking thing is how normal it seems. An astronaut inside a space station needed a ratcheting socket wrench. Someone else on Earth drew it up on a computer then e-mailed the astronaut. The astronaut clicked a button and then the tool was squirted out of a nozzle. Then he picked up and used the tool for the job he needed done. No big deal.
The story itself is almost uneventful – of course we can do these things now. Sure, it happens to be the first time in mankind’s history we have done this. Yes, it is revolutionary to be able to create tools on demand rather than wait months for one to be built planet-side and put onto the next resupply rocket. But, amateurs living in places without even widespread electricity or running water have already built these machines from actual garbage.
Every once in a while a story slaps us with how much the future is now.
These particular 3d prints were duplicated on the ground, and both sets preserved for future comparative analysis to see if microgravity has any effect on 3d prints. They have an eye on sending them to Mars, a journey where resupply is more than just a couple-month inconvenience.
See the first link above for more detail and photos of NASA’s 3d printer and the Microgravity Science Glovebox in the Columbus laboratory module.
The video above shows an animation of what the Canadian Space Agency hopes will be the first successful self-repair of the Mobile Servicing System aboard the ISS. The mobile servicing system is basically a group of several complicated robots that can either perform complicated tasks on their own, or be combined into a larger unit to extend the dexterity of the system as a whole.
The most recent addition to the servicing system is the Special Purpose Dexterous Manipulator, otherwise known as Dextre. Dextre is somewhat reminiscent of a human torso with two enormous arms. It is just one of the Canadian Space Agency’s contributions to the station. It was installed on the station in 2008 to perform activities that would normally require space walks. Dextre’s very first official assignment was successfully completed in 2011 when the robot was used to unpack two pieces for the Kounotori 2 transfer vehicle while the human crew on board the ISS was sleeping.
Dextre is constructed in such a way that it can be grabbed by the Canadarm2 robot and moved to various work sites around the Space Station. Dextre can then operate from the maintenance site on its own while the Canadarm2 can be used for other functions. Dextre can also be operated while mounted to the end of Canadarm2, essentially combining the two robots into one bigger and more dexterous robot.
One of the more critical camera’s on the Canadarm2 has started transmitting hazy images. To fix it, the Canadarm2 will grab onto Dextre, forming a sort of “super robot”. Dextre will then be positioned in such a way that it can remove the faulty camera. The hazy camera will then be mounted to the mobile base component of the Mobile Servicing System. This will give the ISS crew a new vantage point of a less critical location. The station’s human crew will then place a new camera module in Japan’s Kibo module’s transfer airlock. Dextre will be able to reach this new camera and then mount it on the Canadarm2 to replace the original faulty unit. If successful, this mission will prove that the Mobile Servicing System has the capability to repair itself under certain conditions, opening the door for further self-repair missions in the future.
If the space station were left to its own devices, the living quarters would get incredibly hot. There are computers, hardware, and six crew members, all generating heat that must be gotten rid of. To do this, there are two heat exchangers inside the station that take warm water, dump that heat to ammonia, and send that ammonia out to panels outside the station. On December 11, 2013, Loop A of the thermal control system shut down, putting the station one failure away from evacuation. Plans for a spacewalk were tabled, but the ground crew managed to fix this hardware failure by telling the astronauts to push buttons, a metronome, and a software patch.
The problem with Loop A of the Internal Thermal Control System was a flow control valve that regulated the amount of ammonia flowing through the heat exchange. Too much ammonia, and the station would be far too cold. Too little, and it would be too hot. This valve is electronically controlled and takes exactly 13 seconds to move from open to closed. The first attempt at fixing the problem was having ground crew send the command to open the valve and cut the power halfway through. This involved using a metronome app on a phone to send two commands 6.5 seconds apart. It worked, but not quite well enough.
The failure of the metronome technique led [Todd Quasny] to write a script to turn the ‘on’ and ‘off’ commands from the ground to the ISS with millisecond resolution. This meant the commands to control the valve could be sent with the right delay, but they weren’t received with the right delay. This is a problem that had to be fixed from the station’s computers.
To finally solve the problem, ISS software engineer [Steve Joiner] was called in to write a software patch for the thermal control system. This is spaceflight and writing software is a long a laborious process of testing and code reviews. Nevertheless, the team managed to write and upload a patch in just two days.
This patch gave controllers the ability to control the valve with a resolution of 100 milliseconds, good enough for very fine control of the thermal system, and all without requiring the massive amount of planning that goes into a spacewalk or resupply mission.