Hackaday Podcast 078: Happy B-Day MP3, Eavesdropping On A Mars Probe, Shadowcasting 7-Segments, And A Spicy Commodore 64

July 31, 2020 by Mike Szczys No comments

Hackaday editors Elliot Williams and Mike Szczys go down the rabbit hole of hacky hacks. A talented group of radio amateurs have been recording and decoding the messages from Tianwen-1, the Mars probe launched by the Chinese National Space Administration on July 23rd. We don’t know exactly how magnets work, but know they do a great job of protecting your plasma cutter. You can’t beat the retro-chic look of a Commodore 64’s menu system, even if it’s tasked with something mundane like running a meat smoker. And take a walk with us down MP3’s memory lane.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60 MB or so.)

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Falcon 9 Beats Shuttle’s Reflight Record, But Still Has A Long Way To Go

July 27, 2020 by Tom Nardi 77 Comments

Put simply, the goal of any reusable booster is to reduce the cost of getting a payload into space. The comparison is often made to commercial aviation: if you had to throw away the airliner after every flight, nobody could afford the tickets. The fact that the plane can be refueled and flown again and again allows operators to amortize its high upfront cost.

In theory, the same should hold true for orbital rockets. With enough flight experience, you can figure out which parts of the vehicle will need replacement or repair, and how often. Assuming the fuel is cheap enough and the cost of refurbishment doesn’t exceed that of building a new one, eventually the booster will pay for itself. You just need a steady stream of paying customers, which is hardly a challenge given how much we rely on our space infrastructure.

But there’s a catch. For the airliner analogy to really work, whatever inspections and repairs the rocket requires between missions must be done as quickly as possible. The cost savings from reuse aren’t nearly as attractive if you can only fly a few times a year. The key to truly making space accessible isn’t just building a reusable rocket, but attaining rapid reusability.

Which is precisely where SpaceX currently finds themselves. Over the years they’ve mastered landing the Falcon 9’s first stage, and they’ve even proven that the recovered boosters can be safely reused for additional flights. But the refurbishment process is still fairly lengthy. While their latest launch officially broke the record for fastest reflight of a space vehicle that had previously been set by Space Shuttle Atlantis, there’s still a lot of work to be done if SpaceX is ever going to fly their rockets like airplanes.

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Blow Dryers And Metal Shears: Hacks Of Early Falcon 9 Flights

June 13, 2020 by Roger Cheng 10 Comments

Orbiting over our heads right now are two human beings who flew to the International Space Station in a SpaceX Crew Dragon vehicle on top of a Falcon 9. The majority of coverage focused on the years since human spaceflight last launched from Florida, but [Eric Berger] at Ars Technica reminds us it also makes for a grand ten-year celebration of the SpaceX workhorse rocket by sharing some stories from its early days.

Falcon 9 is a huge presence in the global space launch industry today, but ten years ago the future of a young aerospace company was far from certain. The recent uneventful launch is the result of many lessons learned in those ad-hoc days. Some early Falcon 9 flights were successful because the team decided some very unconventional hacks were worth the risk that paid off. A bit of water intrusion? Dry it out with a blow dryer and seal it back up. Small tear in a rocket nozzle? Send in someone to trim a few inches with shears (while the rocket was standing vertical on the launchpad).

Industry veterans appalled at “a cowboy attitude” pounced on every SpaceX failure with “I told you so.” But the disregard for convention is intentional, documented in many places like this old Wired piece from 2012. Existing enshrined aerospace conventions meant the “how” was preserved but the “why” was reduced to “we’ve always done it this way” rarely re-evaluated in light of advancements. Plus the risk-averse industry preferred staying with flight-proven designs, setting up a Catch-22 blocking innovation. SpaceX decided to go a different way, rapidly evolving the Falcon 9 and launching at a high cadence. Learning from all the failures along the way gave them their own set of “why” to back up their “how” growing far beyond blow dryers and metal shears. We’re happy to see the fail-learn-improve cycle at the heart of so many hacker projects have proven effective to send two astronauts to the space station and likely beyond.

[Photo: SpaceX Crew Demo-2 on the launch pad]

Displaying HTML Interfaces And Managing Network Nodes… In Space!

June 8, 2020 by Roger Cheng 44 Comments

The touchscreen interface aboard SpaceX Crew Dragon is just one of its many differences from past space vehicles, but those big screens make an outsized visual impact. Gone are panels filled with indicator needles in gauges, or endless rows of toggle switches. It looked much like web interaction on everyday tablets for good reason: what we see is HTML and JavaScript rendered by the same software core underlying Google’s Chrome browser. This and many other details were covered in a Reddit Ask Me Anything with members of the SpaceX software team.

Various outlets have mentioned Chromium in this context, but without answering the obvious follow-up question: how deep does Chromium go? In this AMA we learn it does not go very deep at all. Chromium is only the UI rendering engine, their fault tolerant flight software interaction is elsewhere. Components such as Chromium are isolated to help keep system behavior predictable, so a frozen tab won’t crash the capsule. Somewhat surprisingly they don’t use a specialized real-time operating system, but instead a lightly customized Linux built with PREEMPT_RT patches for better real-time behavior.

In addition to Falcon rocket and Dragon capsule, this AMA also covered software work for Starlink which offered interesting contrasts in design tradeoffs. Because there are so many satellites (and even more being launched) loss of individual spacecraft is not a mission failure. This gives them elbow room for rapid iteration, treating the constellation more like racks of servers in a datacenter instead of typical satellite operations. Where the Crew Dragon code has been frozen for several months, Starlink code is updated rapidly. Quickly enough that by the time newly launched Starlink satellites reach orbit, their code has usually fallen behind the rest of the constellation.

Finally there are a few scattered answers outside of space bound code. Their ground support displays (visible in Hawthorne mission control room) are built with LabVIEW. They also confirmed that contrary to some claims, the SpaceX ISS docking simulator isn’t actually running the same code as Crew Dragon. Ah well.

Anyone interested in what it takes to write software for space would enjoy reading through these and other details in the AMA. And since it had a convenient side effect of serving as a recruiting event, there are plenty of invitations to apply if anyone has ambitions to join the team. We certainly can’t deny the attraction of helping to write the next chapter in human spaceflight.

[Photo credit: SpaceX]

Phantom Express: The Spaceplane That Never Was

March 27, 2020 by Tom Nardi 12 Comments

Even for those of us who follow space news closely, there’s a lot to keep track of these days. Private companies are competing to develop new human-rated spacecraft and assembling satellite mega-constellations, while NASA is working towards a return the Moon and the first flight of the SLS. Between new announcements, updates to existing missions, and literal rocket launches, things are happening on a nearly daily basis. It’s fair to say we haven’t seen this level of activity since the Space Race of the 1960s.

With so much going on, it’s no surprise that not many people have heard of the XS-1 Phantom Express. A project by the United States Defense Advanced Research Projects Agency (DARPA), the XS-1 was designed to be a reusable launch system that could put small payloads into orbit on short notice. Once its mission was complete, the vehicle was to return to the launch site and be ready for re-flight in as a little as 24 hours.

Alternately referred to as the “DARPA Experimental Spaceplane”, the vehicle was envisioned as being roughly the size of a business jet and capable of carrying a payload of up to 2,300 kilograms (5,000 pounds). It would take off vertically under rocket power and then glide back to Earth at the end of the mission to make a conventional runway landing. At $5 million per flight, its operating costs would be comparable with even the most aggressively priced commercial launch providers; but with the added bonus of not having to involve a third party in military and reconnaissance missions which would almost certainly be classified in nature.

Or at least, that was the idea. Flight tests were originally scheduled to begin this year, but earlier this year prime contractor Boeing abruptly dropped out of the program. Despite six years in development and over $140 million in funding awarded by DARPA, it’s now all but certain that the XS-1 Phantom Express will never get off the ground. Which is a shame, as even in a market full of innovative launch vehicles, this unique spacecraft offered some compelling advantages.

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Rocket Lab Sets Their Sights On Rapid Reusability

August 22, 2019 by Tom Nardi 23 Comments

Not so very long ago, orbital rockets simply didn’t get reused. After their propellants were expended on the journey to orbit, they petered out and fell back down into the ocean where they were obliterated on impact. Rockets were disposable because, as far as anyone could tell, building another one was cheaper and easier than trying to reuse them. The Space Shuttle had proved that reuse of a spacecraft and its booster was possible, but the promised benefits of reduced cost and higher launch cadence never materialized. If anything, the Space Shuttle was often considered proof that reusability made more sense on paper than it did in the real-world.

Rocket Lab CEO Peter Beck with Electron rocket

But that was before SpaceX started routinely landing and reflying the first stage of their Falcon 9 booster. Nobody outside the company really knows how much money is being saved by reuse, but there’s no denying the turn-around time from landing to reflight is getting progressively shorter. Moreover, by performing up to three flights on the same booster, SpaceX is demonstrating a launch cadence that is simply unmatched in the industry.

So it should come as no surprise to find that other launch providers are feeling the pressure to develop their own reusability programs. The latest to announce their intent to recover and eventually refly their vehicle is Rocket Lab, despite CEO Peter Beck’s admission that he was originally against the idea. He’s certainly changed his tune. With data collected over the last several flights the company now believes they have a reusability plan that’s compatible with the unique limitations of their diminutive Electron launch vehicle.

According to Beck, the goal isn’t necessarily to save money. During his presentation at the Small Satellite Conference in Utah, he explained that what they’re really going after is an increase in flight frequency. Right now they can build and fly an Electron every month, and while they eventually hope to produce a rocket a week, even a single reuse per core would have a huge impact on their annual launch capability:

If we can get these systems up on orbit quickly and reliably and frequently, we can innovate a lot more and create a lot more opportunities. So launch frequency is really the main driver for why Electron is going reusable. In time, hopefully we can obviously reduce prices as well. But the fundamental reason we’re doing this is launch frequency. Even if I can get the stage back once, I’ve effectively doubled my production ratio.

But, there’s a catch. Electron is too small to support the addition of landing legs and doesn’t have the excess propellants to use its engines during descent. Put simply, the tiny rocket is incapable of landing itself. So Rocket Lab believes the only way to recover the Electron is by snatching it out of the air before it gets to the ground.

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There And Back Again: A Falcon 9 Launch Story

May 28, 2019 by Tom Nardi 23 Comments

It’s true that I’m not known for keeping particularly regular hours, but even I had my doubts about this plan. We’d go to sleep around midnight, wake up at 3 AM, drive up the coast aimlessly, then turn around and attend a full-day event where we’d have to maintain at least some semblance of professionalism. It was a bad idea, terrible even. But there I was at 11:30 PM sitting in a Waffle House with Thomas, the Supplyframe videographer, getting dangerously close to signing off on it.

Officially we were there to cover the Cornell Cup Finals being held at Kennedy Space Center, but as it so happens, our arrival in Florida perfectly coincided with the launch of CRS-17, SpaceX’s latest International Space Station resupply mission. Technically this was not part of our assignment. But really, what choice did we have?

Even if our respective bosses didn’t see it as a wasted opportunity, we had to consider the locals. In the few hours we’d been here, it seemed the launch was all anyone wanted to talk about. Everyone from the airport shuttle driver to the waitress who brought us our hash browns reminded us a rocket would be lifting off soon. If we didn’t go, then come Friday afternoon we’d be the only people in Cape Canaveral who didn’t have a personal account of the event. By all indications, an unforgivable cultural faux pas in central Florida.

Of course, the truth of the matter is that we didn’t actually need any convincing to go on this adventure. We had the supreme good fortune of finding ourselves in the vicinity of Kennedy Space Center a few hours before they were going to send a rocket thundering off into the black, and there was no way we could just sleep through it. No, there was never any choice in the matter. We were going.

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