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Hackaday Links: March 7, 2021

It’s March, which means Keysight is back in the business of giving away a ton of test gear. Keysight University Live starts on March 15, with daily events the first week followed by a string of weekly live events through April. We always enjoy these Keysight events; sure, they’re clearly intended to sell more gear, but the demos and tutorials are great, and we always learn a lot. There’s also a feeling of community that feels similar to the Hackaday community; just a bunch of electronics nerds getting together to learn and share. If you’re interested in that community, or even if you’re just looking for a chance to win something from the $300,000 pile of goodies, you’ll need to register.

There’s another event coming up that you’ll want to know about: the 2021 Open Hardware Summit. Because 2021 is the new 2020, the summit is being held virtually again, this year on April 9. Tickets are on sale now, and we’re told there are still plenty of Ada Lovelace Fellowships available to those who consider themselves to be a minority in tech. The Fellowship covers the full cost of a ticket; it usually covers travels costs too, but sadly we’re still not there yet.

Once we do start traveling again, you might need to plan more carefully if cities start following the lead of Petaluma, California and start banning the construction of gas stations. The city, about 40 miles (64 km) north of San Francisco, is believed to be the first city in the United States to ban new gas station construction. The city council’s decision also prevents gas station owners from expanding, reconstructing, or relocating existing gas stations. The idea is to create incentives to move toward non-fossil fuel stations, like electric vehicle charging stations and hydrogen fueling. Time will tell how well that works out.

Go home Roomba — you’re drunk. That could be what Roomba owners are saying after an update semi-bricked certain models of the robotic vacuum cleaners. Owners noted a variety of behaviors, like wandering around in circles, bumping into furniture, and inability to make its way back to base for charging. There’s even a timelapse on reddit of a Roomba flailing about pathetically in a suspiciously large and empty room. The drunken analogy only goes so far, though, since we haven’t seen any reports of a Roomba barfing up the contents of its dust bin. But we’re still holding out hope.

And finally, if you’re not exactly astronaut material but still covet a trip to space, you might luck out courtesy of Japanese billionaire Yusaku Maezawa. He’s offering to pay the way for eight people from around the world on a planned flight to the Moon and back in 2023. Apparently, Maezawa bought up all the seats for the flight back in 2018 with the intention of flying a group of artists to space. His thinking has changed, though, and now he’s opening up the chance to serve as ballast join the crew to pretty much any rando on the planet. Giving away rides on Starship might be a harder sell after this week’s test, but we’re sure he’ll find plenty of takers. And to be honest, we wish the effort well — the age of routine civilian space travel can’t come soon enough for us.

Spacing Out: Launch Successes And Failures, Next Stop Mars, Rocket Catching, & Space Stations

As large sections of the globe have seen themselves plunged into further resurgences of the pandemic over the past few weeks there has been no let-up in the world of space exploration even for the Christmas holidays, so here we are with another Spacing Out column in which we take a look at what’s going up, what’s flying overhead, and what’s coming down.

Not today, Paul. r2hox from Madrid, Spain, CC BY-SA 2.0.
Not today, Paul. r2hox from Madrid, Spain, CC BY-SA 2.0.

December was eventful, with China returning lunar samples and Japan doing the same with asteroid dust. And it was reported that we  might just possibly have detected radio waves from ET. The truth may be out there and we sincerely want to believe, but this widely reported signal from Proxima Centauri probably isn’t the confirmation of alien life we’ve all been waiting for.

There has been no shortage of launches over the last month from the usual agencies and companies, with a first launch from China of their Long March 8 heavy lift rocket from the Wenchang launch site in Hainan Province. Its payload of five satellites made it safely to orbit, and we expect the rocket will be a workhorse of their future exploration programme. Meanwhile SpaceX conducted a high-altitude test of their Starship SN8 vehicle, which proceeded according to plan until the craft was approaching the landing pad, at which point the failure of one of its engines to fire caused a spectacular crash. This does not equate to an unsuccessful test flight as it performed faultlessly in the rest of its manoeuvres, but it certainly made for some impressive video.

On the subject of SpaceX and Starship, Elon Musk has said he will sell all his personal property to fund a Martian colony. This will require a fleet of up to 1000 Starships, with three launches a day to ferry both colonists and supplies to the Red Planet. He attracted controversy though by saying that interplanetary immigration would be open to people of all means with loans available for the estimated $50,000 one-way travel cost, and Martian jobs on offer to enable the debt to be paid. Many critics replied to his Tweets likening the idea to indentured servitude. It’s worth remembering that Musk is the master of the grand publicity stunt, and while it seems a good bet that SpaceX will indeed reach Mars, it’s also not inconceivable that his timeline and plans might be somewhat optimistic.

A more tangible story from SpaceX comes in their super heavy booster rocket, which is to be reusable in the same manner as their existing Falcon 9, but not landing on its own legs in the manner of the earlier rocket. It will instead dock with its launch tower, being caught by the same support structures used to stabilise it before launch. At first glance this might seem too difficult to succeed, but no doubt people expressed the same doubts before the Falcon 9s performed their synchronised landings.

Finally away from more troubling developments in the political field, The Hill takes a look at some of those likely to have a hand in providing a commercial replacement for the ISS when it eventually reaches the end of its life. They examine the likely funding for NASA’s tenancy on the station, and looked at the cluster of Texas-based companies gearing up for space station manufacture. That’s right — space station modules from the likes of Axiom Space will become a manufactured assembly rather than one-off commissions. The decades beyond the ISS’s current 2030 projected end of life are likely to have some exciting developments in orbit.

The coming year is likely to be an exciting one, with a brace of missions heading to Mars for February as well as a new space station to catch our attention. The Chinese aren’t content to stop at the Moon, with their Tianwen-1 Mars mission due to start exploring our planetary neighbour, and the first Tianhe module of what will become their much larger space station taking to the skies in the coming year. Meanwhile the Red planet will see NASA’s Perseverance rover also reaching its surface, taking with it the Ingenuity helicopter. Finally, the United Arab Emirates’ Hope probe will go into orbit, making the second month one that should have plenty of news.

Wherever you are, keep yourself safe from Earth-bound viruses, and keep looking at the skies in 2021.

SpaceX Starship Replica Attempts The Bellyflop

SpaceX are perhaps most well known for their vertically-landing reusable rocket technology. The latest such effort is the Starship, which recently underwent a fiery test in the last month to attempt a bellyflop maneuver. [Nicholas Rehm] wanted to attempt a similar flight profile in the local park, and set to building an RC Starship of his own.

The build is like a few we’ve seen before, in which electric power is used to propel a rocket-like craft straight upwards using propellers and active stabilization. In this case, there’s a pair of twin motors with counter-rotating propellers which can pivot to direct their thrust, as well as four external control surfaces. These are all under the command of [Nicholas]’s custom flight controller.

Upon testing the rig, [Nicholas] was able to execute a smooth ascent, followed by a bellyflop, before a smooth return to vertical flight and descent. Landing vertically on the grass was out of the question, due to the rough surface, but we imagine it would be doable with the right landing gear attached.

While flight without wings in this manner isn’t particularly efficient, it’s great to see what can be achieved with smart use of control systems engineering to keep a craft stable. We look forward to seeing [Nicholas]’s next attempts, too. Video after the break.

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RC Starship Perfects Its Skydiving Routine

There’s a good chance you already saw SpaceX’s towering Starship prototype make its impressive twelve kilometer test flight. While the attempt ended with a spectacular fireball, it was still a phenomenal success as it demonstrated a number of concepts that to this point had never been attempted in the real world. Most importantly, the “Belly Flop” maneuver which sees the 50 meter (160 foot) long rocket transition from vertical flight to a horizontal semi-glide using electrically actuated flight surfaces.

Finding himself inspired by this futuristic spacecraft, [Nicholas Rehm] has designed his own radio controlled Starship that’s capable of all the same aerobatic tricks as the real-thing. It swaps the rocket engines for a pair of electric brushless motors, but otherwise, it’s a fairly accurate recreation of SpaceX’s current test program vehicle. As you can see in the video after the break, it’s even able to stick the landing. Well, sometimes anyway.

Just like the real Starship, vectored thrust is used to both stabilize the vehicle during vertical ascent and help transition it into and out of horizontal flight. Of course, there are no rocket nozzles to slew around, so [Nicholas] is using servo-controlled vanes in the bottom of the rocket to divert the airflow from the motors. Servos are also used to control the external control surfaces, which provide stability and a bit of control authority as the vehicle is falling.

As an interesting aside, Internet sleuths looking through pictures of the Starship’s wreckage have noted that SpaceX appears to be actuating the flaps with gearboxes driven by Tesla motors. The vehicle is reportedly using Tesla battery packs as well. So while moving the control surfaces on model aircraft with battery-powered servos might historically have been a compromise to minimize internal complexity, here it’s actually quite close to the real thing.

Unfortunately, the RC Starship made a hard landing of its own on a recent test flight, so [Nicholas] currently has to rebuild the craft before he can continue with further development. We’re confident he’ll get it back in the air, though it will be interesting to see whether or not he’s flying before SpaceX fires off their next prototype.

Continue reading “RC Starship Perfects Its Skydiving Routine”

Floating Spaceports For Future Rockets

While early prototypes for SpaceX’s Starship have been exploding fairly regularly at the company’s Texas test facility, the overall program has been moving forward at a terrific pace. The towering spacecraft, which CEO Elon Musk believes will be the key to building a sustainable human colony on Mars, has gone from CGI rendering to flight hardware in just a few short years. That’s fast even by conventional rocket terms, but then, there’s little about Starship that anyone would dare call conventional.

An early Starship prototype being assembled.

Nearly every component of the deep space vehicle is either a technological leap forward or a deviation from the norm. Its revolutionary full-flow staged combustion engines, the first of their kind to ever fly, are so complex that the rest of the aerospace industry gave up trying to build them decades ago. To support rapid reusability, Starship’s sleek fuselage abandons finicky carbon fiber for much hardier (and heavier) stainless steel; a material that hasn’t been used to build a rocket since the dawn of the Space Age.

Then there’s the sheer size of it: when Starship is mounted atop its matching Super Heavy booster, it will be taller and heavier than both the iconic Saturn V and NASA’s upcoming Space Launch System. At liftoff the booster’s 31 Raptor engines will produce an incredible 16,000,000 pounds of thrust, unleashing a fearsome pressure wave on the ground that would literally be fatal for anyone who got too close.

Which leads to an interesting question: where could you safely launch (and land) such a massive rocket? Even under ideal circumstances you would need to keep people several kilometers away from the pad, but what if the worst should happen? It’s one thing if a single-engine prototype goes up in flames, but should a fully fueled Starship stack explode on the pad, the resulting fireball would have the equivalent energy of several kilotons of TNT.

Thanks to the stream of consciousness that Elon often unloads on Twitter, we might have our answer. While responding to a comment about past efforts to launch orbital rockets from the ocean, he casually mentioned that Starship would likely operate from floating spaceports once it started flying regularly:

While history cautions us against looking too deeply into Elon’s social media comments, the potential advantages to launching Starship from the ocean are a bit too much to dismiss out of hand. Especially since it’s a proven technology: the Zenit rocket he references made more than 30 successful orbital launches from its unique floating pad.

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Levitating Starship Model Comes In For A Landing

If everything goes according to plan, Elon Musk says the first generation of SpaceX’s massive Starship will make an orbital flight before the end of 2020. That’s a pretty bold claim, but when you’ve made landing rockets on their tails as in the old science fiction pulp magazines seem routine, we suppose you’ve earned the right to a bit of bravado. We’re excited to see the vehicle evolve over the next several months, but even if the real one stays grounded, we’ll gladly take this “flying” Starship model from [Chris Chimienti] as a consolation prize.

A magnetic levitation module, we’re officially in the future.

Feeling a bit let down by the 3D printable models of the Starship he found online, [Chris] set out to build his own. But it wasn’t enough to just make his bigger, stronger, and more accurate to Starship’s current design; he also wanted to make it a bit more exciting. Some RGB LEDs an Arduino embedded in the “cloud” stand the rocket sits on was a good start, and the landing pad inspired by SpaceX’s real autonomous spaceport drone ship Just Read the Instructions looks great all lit up.

But this is Starship we’re talking about, a vehicle that could literally push humanity towards being a multi-planet species. To do it justice, you’ve really got to knock it out of the park. So [Chris] found a magnetic levitation module online that could support a few hundred grams, and set to work on making his plastic Starship actually hover over the landing pad.

As you might imagine, it was a bit tricky. The first versions of the rocket looked great but came out too heavy, so he switched over to printing the model in so-called “spiral vase mode” which made it entirely hollow. Now far lighter and with a magnetic plate fit into the bottom, it was stable enough to float on its own. For the final touch, [Chris] added some red LEDs and a coin cell battery to the base of the Starship so it looks like the sleek craft is performing a last-second landing burn with its “impossible” full-flow staged combustion engines.

This isn’t the first time we’ve seen a model rocket with an electronic glowing cloud under it, but it’s certainly the first one we’ve seen that could levitate in mid-air. While this little rocket might not make it all the way to Mars, we wouldn’t be surprised to see it touching down on the desks of other hackers and makers in the near future.

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The “Impossible” Tech Behind SpaceX’s New Engine

Followers of the Church of Elon will no doubt already be aware of SpaceX’s latest technical triumph: the test firing of the first full-scale Raptor engine. Of course, it was hardly a secret. As he often does, Elon has been “leaking” behind the scenes information, pictures, and even video of the event on his Twitter account. Combined with the relative transparency of SpaceX to begin with, this gives us an exceptionally clear look at how literal rocket science is performed at the Hawthorne, California based company.

This openness has been a key part of SpaceX’s popularity on the Internet (that, and the big rockets), but its been especially illuminating in regards to the Raptor. The technology behind this next generation engine, known as “full-flow staged combustion” has for decades been considered all but impossible by the traditional aerospace players. Despite extensive research into the technology by the Soviet Union and the United States, no engine utilizing this complex combustion system has even been flown. Yet, just six years after Elon announced SpaceX was designing the Raptor, they’ve completed their first flight-ready engine.

The full-flow staged combustion engine is often considered the “Holy Grail” of rocketry, as it promises to extract the most possible energy from its liquid propellants. In a field where every ounce is important, being able to squeeze even a few percent more thrust out of the vehicle is worth fighting for. Especially if, like SpaceX, you’re planning on putting these new full-flow engines into the world’s largest operational booster rocket and spacecraft.

But what makes full-flow staged combustion more efficient, and why has it been so difficult to build an engine that utilizes it? To understand that, we’ll need to first take a closer look at more traditional rocket engines, and the design paradigms which have defined them since the very beginning.

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