The “Impossible” Tech Behind SpaceX’s New Engine

February 13, 2019 by Tom Nardi 92 Comments

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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Automate The Freight: Amazon Tackles The Last Mile Problem On Wheels

February 11, 2019 by Dan Maloney 85 Comments

We’ve been occasionally exploring examples of what could be the killer application for self-driving vehicles: autonomous freight deliveries, both long-haul and local, as well as some special use cases. Some, like UAV delivery of blood and medical supplies in Kenya, have taken off and are becoming both profitable and potentially life-saving. Others, like driverless long-haul trucking, made an initial splash but appear to have gone quiet since then. This is to be expected, as the marketplace picks winners and losers in a neverending quest to maximize return on investment. But the whole field seems to have gotten a bit sleepy lately, with no big news of note for quite a while.

That changed last week with Amazon’s announcement of Scout, their autonomous delivery vehicle. Announced first on Amazon’s blog and later picked up by the popular and tech press who repeated the Amazon material almost verbatim, Scout appears at first glance to be a serious attempt by Amazon to own the “last mile” of delivery – the local routes that are currently plied by the likes of UPS, FedEx, and various postal services. Or is it?

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FAA Proposes Refined Drone Regulations

February 4, 2019 by Tom Nardi 77 Comments

The wheels of government move slowly, far slower than the pace at which modern technology is evolving. So it’s not uncommon for laws and regulations to significantly lag behind the technology they’re aimed at reigning in. This can lead to something of a “Wild West” situation, which could either be seen as a good or bad thing depending on what side of the fence you’re on.

In the United States, it’s fair to say that we’ve officially moved past the “Wild West” stage when it comes to drone regulations. Which is not to say that remotely controlled (RC) aircraft were unregulated previously, but that the rules which governed them simply couldn’t keep up with the rapid evolution of the technology we’ve seen over the last few years. The previous FAA regulations for remotely operated aircraft were written in an era where RC flights were lower and slower, and long before remote video technology moved the operator out of the line of sight of their craft.

To address the spike in not only the capability of RC aircraft but their popularity, the Federal Aviation Administration was finally given the authority to oversee what are officially known as Unmanned Aerial Systems (UAS) with the repeal of Section 336 in the FAA Reauthorization Act of 2018. Section 336, known as the “Special Rule for Model Aircraft” was previously put in place to ensure the FAA’s authority was limited to “real” aircraft, and that small hobby RC aircraft would not be subject to the same scrutiny as their full-size counterparts. With Section 336 gone, one could interpret the new FAA directives as holding manned and unmanned aircraft and their operators to the same standards; an unreasonable position that many in the hobby strongly rejected.

At the time, the FAA argued that the repealing Section 336 would allow them to create new UAS regulations from a position of strength. In other words, start with harsh limits and regulations, and begin to whittle them down until a balance is found that everyone is happy with. U.S. Secretary of Transportation Elaine L. Chao has revealed the first of these refined rules are being worked on, and while they aren’t yet official, it seems like the FAA is keeping to their word of trying to find a reasonable middle ground for hobby fliers.

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Drone Sightings, A New British Comedy Soap Opera

January 28, 2019 by Jenny List 41 Comments

There’s a new soap opera that I can’t stop watching. Actually, I wish I could change the channel but this is unfortunately happening in real life. It’s likely the ups and downs of drone sightings would be too far fetched for fiction anyway.

If you aren’t British, maybe you will know a little of our culture through the medium of television. We don’t all live in stately homes like Downton Abbey of course, instead we’re closer to the sometimes comedic sets, bad lighting, and ridiculously complicated lives of the residents of Coronation Street or of Albert Square in Eastenders that you may have flashed past late at night on a high-number channel.

Our new comedy soap lacks the regional accents of Emmerdale or Hollyoaks, but has no less of the farce about it. Here at Hackaday we’ve brought you news of the UK’s peculiar habit of bad reporting and shoddy investigation of questionable drone sightings several times over the last year or two. Most recently we covered a series of events before Christmas that closed Gatwick, London’s second airport for several days over what turned out to be nothing of substance.

Unfortunately it didn’t end there. We’re back once more to catch up with the latest events down on the tarmac, and come away with a fresh set of reasonable questions unanswered by the popular coverage of the matter.

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The Short And Tragic Story Of Life On The Moon

January 23, 2019 by Tom Nardi 66 Comments

The Moon is a desolate rock, completely incapable of harboring life as we know it. Despite being our closest celestial neighbor, conditions on the surface couldn’t be more different from the warm and wet world we call home. Variations in surface temperature are so extreme, from a blistering 106 C (223 F) during the lunar day to a frigid -183 C (-297 F) at night, that even robotic probes struggle to survive. The Moon’s atmosphere, if one is willing to call the wispy collection of oddball gasses including argon, helium, and neon at nearly negligible concentrations an atmosphere, does nothing to protect the lunar surface from being bombarded with cosmic radiation.

Yet for a brief time, very recently, life flourished on the Moon. Of course, it did have a little help. China’s Chang’e 4 lander, which made a historic touchdown in the Von Kármán crater on January 3rd, brought with it an experiment designed to test if plants could actually grow on the lunar surface. The device, known as the Lunar Micro Ecosystem (LME), contained air, soil, water, and a collection of seeds. When it received the appropriate signal, LME watered the seeds and carefully monitored their response. Not long after, Chinese media proudly announced that the cotton seeds within the LME had sprouted and were doing well.

Unfortunately, the success was exceptionally short-lived. Just a few days after announcing the success of the LME experiment, it was revealed that all the plants which sprouted had died. The timeline here is a bit hazy. It was not even immediately clear if the abrupt end of the LME experiment was intentional, or due to some hardware failure.

So what exactly do we know about Chang’e 4’s Lunar Micro Ecosystem, and the lifeforms it held? Why did the plants die? But perhaps most importantly, what does all this have to do with potential future human missions to that inhospitable rock floating just a few hundred thousand kilometers away from us?

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Scramjet Engines On The Long Road To Mach 5

January 16, 2019 by Tom Nardi 58 Comments

When Charles “Chuck” Yeager reached a speed of Mach 1.06 while flying the Bell X-1 Glamorous Glennis in 1947, he became the first man to fly faster than the speed of sound in controlled level flight. Specifying that he reached supersonic speed “in controlled level flight” might seem superfluous, but it’s actually a very important distinction. There had been several unconfirmed claims that aircraft had hit or even exceeded Mach 1 during the Second World War, but it had always been during a steep dive and generally resulted in the loss of the aircraft and its pilot. Yeager’s accomplishment wasn’t just going faster than sound, but doing it in a controlled and sustained flight that ended with a safe landing.

In that way, the current status of hypersonic flight is not entirely unlike that of supersonic flight prior to 1947. We have missiles which travel at or above Mach 5, the start of the hypersonic regime, and spacecraft returning from orbit such as the Space Shuttle can attain speeds as high as Mach 25 while diving through the atmosphere. But neither example meets that same requirement of “controlled level flight” that Yeager achieved 72 years ago. Until a vehicle can accelerate up to Mach 5, sustain that speed for a useful period of time, and then land intact (with or without a human occupant), we can’t say that we’ve truly mastered hypersonic flight.

So why, nearly a century after we broke the sound barrier, are we still without practical hypersonic aircraft? One of the biggest issues historically has been the material the vehicle is made out of. The Lockheed SR-71 “Blackbird” struggled with the intense heat generated by flying at Mach 3, which ultimately required it to be constructed from an expensive and temperamental combination of titanium and polymer composites. A craft which flies at Mach 5 or beyond is subjected to even harsher conditions, and it has taken decades for material science to rise to the challenge.

With modern composites and the benefit of advanced computer simulations, we’re closing in on solving the physical aspects of surviving sustained hypersonic flight. With the recent announcement that Russia has put their Avangard hypersonic glider into production, small scale vehicles traveling at high Mach numbers for extended periods of time are now a reality. Saying it’s a solved problem isn’t quite accurate; the American hypersonic glider program has been plagued with issues related to the vehicle coming apart under the stress of Mach 20 flight, which heats the craft’s surface to temperatures in excess of 1,900 C (~3,500 F). But we’re getting closer, and it’s no longer the insurmountable problem it seemed a few decades ago.

Today, the biggest remaining challenge is propelling a hypersonic vehicle in level flight for a useful period of time. The most promising solution is the scramjet, an engine that relies on the speed of the vehicle itself to compress incoming air for combustion. They’re mechanically very simple, and the physics behind it have been known since about the time Yeager was climbing into the cockpit of the X-1. Unfortunately the road towards constructing, much less testing, a full scale hypersonic scramjet aircraft has been a long and hard one.

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UPnP, Vulnerability As A Feature That Just Won’t Die

January 14, 2019 by Jenny List 25 Comments

UPnP — in a perfect world it would have been the answer to many connectivity headaches as we add more devices to our home networks. But in practice it the cause of a lot of headaches when it comes to keeping those networks secure.

It’s likely that many Hackaday readers provide some form of technical support to relatives or friends. We’ll help sort out Mom’s desktop and email gripes, and we’ll set up her new router and lock it down as best we can to minimise the chance of the bad guys causing her problems. Probably one of the first things we’ll have all done is something that’s old news in our community; to ensure that a notorious vulnerability exposed to the outside world is plugged, we disable UPnP on whatever cable modem or ADSL router her provider supplied.

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