Astro Pi Mk II, The New Raspberry Pi Hardware Headed To The Space Station

Back in 2015, European Space Agency (ESA) astronaut Tim Peake brought a pair of specially equipped Raspberry Pi computers, nicknamed Izzy and Ed, onto the International Space Station and invited students back on Earth to develop software for them as part of the Astro Pi Challenge. To date, more than 50,000 young people have had their code run on one of the single-board computers; making them arguably the most popular, and surely the most traveled, Raspberry Pis in the solar system.

While Izzy and Ed are still going strong, the ESA has decided it’s about time these veteran Raspberries finally get the retirement they’re due. Set to make the journey to the ISS in December aboard a SpaceX Cargo Dragon, the new Astro Pi MK II hardware looks quite similar to the original 2015 version at first glance. But a peek inside its 6063-grade aluminium flight case reveals plenty of new and improved gear, including a Raspberry Pi 4 Model B with 8 GB RAM.

The beefier hardware will no doubt be appreciated by students looking to push the envelope. While the majority of Python programs submitted to the Astro Pi program did little more than poll the current reading from the unit’s temperature or humidity sensors and scroll messages for the astronauts on the Astro Pi’s LED matrix, some of the more advanced projects were aimed at performing legitimate space research. From using the onboard camera to image the Earth and make weather predictions to attempting to map the planet’s magnetic field, code submitted from teams of older students will certainly benefit from the improved computational performance and expanded RAM of the newest Pi.

As with the original Astro Pi, the ESA and the Raspberry Pi Foundation have shared plenty of technical details about these space-rated Linux boxes. After all, students are expected to develop and test their code on essentially the same hardware down here on Earth before it gets beamed up to the orbiting computers. So let’s take a quick look at the new hardware inside Astro Pi MK II, and what sort of research it should enable for students in 2022 and beyond.

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Hackaday Links: September 12, 2021

The last thing an astronaut or cosmonaut on the International Space Stations wants to hear from one of their crewmates is, “Do you smell plastic burning?” But that’s apparently what happened this week aboard the increasingly problematic spacecraft, as the burning smell and visible smoke spread from the Russian Zvezda module to the American side of town. The reports say it occurred while charging the station’s batteries, and we all know how dicey that can get. But apparently, the situation resolved itself somehow, as normal operations continued soon after the event. Between reports of cracks, air leaks, problems with attitude control, and even accusations of sabotage, the ISS is really starting to show its age.

Speaking of burning and batteries, normally a story about burning Tesla batteries wouldn’t raise our eyebrows much. But this story out of California introduces a potential failure mode for Tesla batteries that we hadn’t considered before. It seems a semi-truck with a load of Tesla batteries lost its brakes on Interstate 80 in the Sierra Nevada mountains and ended up flipping across the highway. Video from the scene shows the cargo, which looks like replacement batteries or perhaps batteries salvaged from wrecked cars, scattered across the highway on their shipping pallets. A fire was reported, but it’s not clear whether it was one of the batteries which had gotten compromised in the crash, or if it was something other than the batteries. Still, we hadn’t considered the potential for disaster while shipping batteries like that.

Attention all GNURadio fans — GRCon21 is rapidly approaching. Unlike most of the conferences over the last year and half, GRCon21 will actually be both live and online. We always love the post-conference dump of talks, which cover such a wide range of topics and really dive deeply into so many cool areas. We’re especially looking forward to the SETI talks, and we’re pleased to see our friend Hash, who was on the Hack Chat a while back, scheduled to talk about his smart-meter hacking efforts. The conference starts on September 20 and is being held in Charlotte, North Carolina, and virtually of course. If you attend, make sure to drop tips to your favorite talks in the tips line so we can share them with everyone.

We got a tip this week on a video about how 1/4-wave tuning stubs work. It’s a simple demonstration using a length of coax, a signal generator, and an oscilloscope to show how an unterminated feedline can reflect RF back to the transmitter, and how that can be used to build super-simple notch filters and impedance transformers. We love demos that make the mysteries of RF a little simpler — W2AEW’s videos come to mind, like this one on standing waves.

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As ISS Enters Its Final Years, Politics Take Center Stage

There was a time when the idea of an international space station would have been seen as little more than fantasy. After all, the human spaceflight programs of the United States and the Soviet Union were started largely as a Cold War race to see which country would be the first to weaponize low Earth orbit and secure what military strategists believed would be the ultimate high ground. Those early rockets, not so far removed from intercontinental ballistic missiles (ICBMs), were fueled as much by competition as they were kerosene and liquid oxygen.

Space Shuttle docked to Mir space station in 1995.
Atlantis docked to Mir in 1995.

Luckily, cooler heads prevailed. The Soviet Almaz space stations might have carried a 23 mm cannon adapted from tail-gun of the Tu-22 bomber to ward off any American vehicles that got too close, but the weapon was never fired in anger. Eventually, the two countries even saw the advantage of working together. In 1975, a joint mission saw the final Apollo capsule dock with a Soyuz by way of a special adapter designed to make up for the dissimilar docking hardware used on the two spacecraft.

Relations further improved following the dissolution of the Soviet Union in 1991, with America’s Space Shuttle making nine trips to the Russian Mir space station between 1995 and 1997. A new era of cooperation had begun between the world’s preeminent space-fairing countries, and with the engineering lessons learned during the Shuttle-Mir program, engineers from both space agencies began laying the groundwork for what would eventually become the International Space Station.

Unfortunately after more than twenty years of continuous US and Russian occupation of the ISS, it seems like the cracks are finally starting to form in this tentative scientific alliance. With accusations flying over who should take the blame for a series of serious mishaps aboard the orbiting laboratory, the outlook for future international collaboration in Earth orbit and beyond hasn’t been this poor since the height of the Cold War.

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ISS Gets Roll-Out Solar Panels In Post-Shuttle Fix

Astronauts are currently installing the first of six new solar arrays on the International Space Station (ISS), in a bid to bolster the reduced power generation capability of the original panels which have now been in space for over twenty years. But without the Space Shuttle to haul them into orbit, developing direct replacements for the Stations iconic 34 meter (112 foot) solar “wings” simply wasn’t an option. So NASA has turned to next-generation solar arrays that roll out like a tape measure and are light and compact enough for the SpaceX Dragon to carry them into orbit.

Space Shuttle Atlantis carrying part of the ISS truss.

Considering how integral the Space Shuttle was to its assembly, it’s hardly a surprise that no major modules have been added to the ISS since the fleet of winged spacecraft was retired in 2011. The few small elements that have been installed, such as the new International Docking Adapters and the Nanoracks “Bishop” airlock, have had to fit into the rear unpressurized compartment of the Dragon capsule. While a considerable limitation, NASA had planned for this eventuality, with principle construction of the ISS always intended to conclude upon the retirement of the Shuttle.

But the International Space Station was never supposed to last as long as it has, and some components are starting to show their age. The original solar panels are now more than five years beyond their fifteen year service life, and while they’re still producing sufficient power to keep the Station running in its current configuration, their operational efficiency has dropped considerably with age. So in January NASA announced an ambitious timeline for performing upgrades the space agency believes are necessary to keep up with the ever-increasing energy demands of the orbiting laboratory.

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ISS Artificial Gravity Study Shows Promise For Long Duration Spaceflight

The International Space Station is humanity’s most expensive gym membership.

Since the earliest days of human spaceflight, it’s been understood that longer trips away from Earth’s gravity can have a detrimental effect on an astronaut’s body. Floating weightless invariably leads to significantly reduced muscle mass in the same way that a patient’s muscles can atrophy if they spend too much time laying in bed. With no gravity to constantly fight against, an astronauts legs, back, and neck muscles will weaken from disuse in as little as a week. While this may not pose an immediate problem during spaceflight, astronauts landing back on Earth in this physically diminished state are at a higher risk of injury.

Luckily this problem can be largely mitigated with rigorous exercise, and any orbiting vessel spacious enough to hold human occupants for weeks or months will by necessity have enough internal volume to outfit it with basic exercise equipment such as a treadmill or a resistance machine. In practice, every space station since the Soviet Union’s Salyut 1 in 1971 has featured some way for its occupants to workout while in orbit. It’s no replacement for being on Earth, as astronauts still return home weaker than when they left, but it’s proven to be the most practical approach to combating the debilitating aspects of long duration spaceflight.

Early NASA concept for creating artificial gravity.

Of course, there’s an obvious problem with this: every hour spent exercising in space is an hour that could be better spent doing research or performing maintenance on the spacecraft. Given the incredible cost of not just putting a human into orbit, but keeping them there long-term, time is very literally money. Which brings us back to my original point: astronauts spending two or more hours each day on the International Space Station’s various pieces of exercise equipment just to stave off muscle loss make it the world’s most expensive gym membership.

The ideal solution, it’s been argued, is to design future spacecraft with the ability to impart some degree of artificial gravity on its passengers through centripetal force. The technique is simple enough: just rotate the craft along its axis and the crew will “stick” to the inside of the hull. Unfortunately, simulating Earth-like gravity in this way would require the vessel to either be far larger than anything humanity has ever launched into space, or rotate at a dangerously high speed. That’s a lot of risk to take on for what’s ultimately just a theory.

But a recent paper from the University of Tsukuba in Japan may represent the first real steps towards the development of practical artificial gravity systems aboard crewed spacecraft. While their study focused on mice rather than humans, the results should go a long way to codifying what until now was largely the stuff of science fiction.

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Crew Dragon’s Short Hop Begins The Era Of Valet Parking At The ISS

They weren’t scheduled to return to Earth until April 28th at the earliest, so why did NASA astronauts Michael Hopkins, Victor Glover, and Shannon Walker, along with Japan Aerospace Exploration Agency (JAXA) astronaut Soichi Noguchi, suit up and climb aboard the Crew Dragon Resilience on April 5th? Because a previously untested maneuver meant that after they closed the hatch between their spacecraft and the International Space Station, there was a chance they weren’t going to be coming back.

On paper, moving a capsule between docking ports seems simple enough. All Resilience had to do was undock from the International Docking Adapter 2 (IDA-2) located on the front of the Harmony module, itself attached to the Pressurized Mating Adapter 2 (PMA-2) that was once the orbital parking spot for the Space Shuttle, and move over to the PMA-3/IDA-3 on top of Harmony. It was a short trip through open space, and when the crew exited their craft and reentered the Station at the end of it, they’d only be a few meters from where they started out approximately 45 minutes prior.

The maneuver was designed to be performed autonomously, so technically the crew didn’t need to be on Resilience when it switched docking ports. But allowing the astronauts to stay aboard the station while their only ride home undocked and flew away without them was a risk NASA wasn’t willing to take.

What if the vehicle had some issue that prevented it from returning to the ISS? A relocation of this type had never been attempted by an American spacecraft before, much less a commercial one like the Crew Dragon. So while the chances of such a mishap were slim, the crew still treated this short flight as if it could be their last day in space. Should the need arise, all of the necessary checks and preparations had been made so that the vehicle could safely bring its occupants back to Earth.

Thankfully, that wasn’t necessary. The autonomous relocation of Crew Dragon Resilience went off without a hitch, and SpaceX got to add yet another “first” to their ever growing list of accomplishments in space. But this first relocation of an American spacecraft at the ISS certainly won’t be the last, as the comings and goings of commercial spacecraft will only get more complex in the future.

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Spacing Out: StarShip Explodes (Again), Passenger Space Flight, Space Bugs, Astronaut Bone, And Martian Water

This time I promise I only have a couple of stories from Elon Musk’s company. SpaceX’s latest Starship test launch ended in another explosion, proving that space hardware remains hard to get right. We’ll keep watching as they keep launching, and it can’t be long until they’ve ironed out all the problems. Meanwhile there’s brighter news from the company’s Crew Dragon, a modified version of the capsule with the forward docking ring replaced by a transparent dome is planned for launch in September with the company’s first flight carrying civilian passengers. It’s doubtless unwelcome news for Virgin Galactic, whose suborbital passenger flights are edging closer to reality with the unveiling of their first SpaceShip III craft. Finally, a Falcon 9 upper stage broke up on re-entry over the northwestern USA, giving observers on the ground a spactacular show.

Spectacular view of the Falcon 9 debris. Via Lu Jerz

Meanwhile up there in orbit there have been found on the ISS some strains of bacteria previously unknown to scientists on Earth, but it’s not yet time to panic about Mutant Bugs From Space. It seems these bacteria are of a type that is essential in the growing of plants, so it’s likely they originally hitched a ride up with one of the several plant-growing experiments that have taken place over the station’s lifetime. Staying on the ISS, astronauts visiting the station have been at the centre of a recently published study looking at loss of bone density over long periods in space. The bone experts found that bone density could still be lost despite the astronauts’ in-flight exercise programs, and concluded that exercise regimes pre-flight should be taken into account for future in-orbit exercise planning.

Further away from Earth, the ESA Mars Express satellite has been used for a multi-year study of water loss to space from the Martian atmosphere. The ESA scientists identified the seasonal mechanism that leads to the planet’s upper atmosphere having an excess of water and in particular the effect of the periodic planet-wide dust storms on accelerating water loss, but failed to account for the water that they estimate Mars must have lost over its history. From a study of water-created surface features they can estimate how much liquid the planet once had, yet the atmospheric losses fail to account for it all. Has it disappeared underground? More studies are required before we’ll have an answer.

The exciting news over the coming days will no doubt be the Ingenuity Martian helicopter, which we have seen slowly unfolding itself prior to unloading from the belly of the Perseverence rover. If all goes according to plan the little craft will be set down before the rover trundles off to a safe distance, and the historic flight will take place on April 8th. We’ll be on the edges of our seats, and no doubt you will be, too.