When it comes to space exploration, we often think of billion-dollar projects—NASA’s Artemis missions, ESA’s Mars rovers, or China’s Tiangong station. Yet, a group of U.S. students at USC’s Rocket Propulsion Lab (RPL) has achieved something truly extraordinary—a reminder that groundbreaking work doesn’t always require government budgets. On October 20, their homemade rocket, Aftershock II, soared to an altitude of 470,000 feet, smashing the amateur spaceflight altitude and speed records held for over two decades. Intrigued? Check out the full article here.
The 14-foot, 330-pound rocket broke the sound barrier within two seconds, reaching hypersonic speeds of Mach 5.5—around 3,600 mph. But Aftershock II didn’t just go fast; it climbed higher than any amateur spacecraft ever before, surpassing the 2004 GoFast rocket’s record by 90,000 feet. Even NASA-level challenges like thermal protection at hypersonic speeds were tackled using clever tricks. Titanium-coated fins, specially engineered heat-resistant paint, and a custom telemetry module ensured the rocket not only flew but returned largely intact.
This achievement feels straight out of a Commander Keen adventure—scrappy explorers, daring designs, and groundbreaking success against all odds. The full story is a must-read for anyone dreaming of building their own rocket.
As the link shows for our SI friends, that is 27,400 meters.
27,400 meters above the previous record for a total of 143km (470,000 feet)
powyżej linii Carmana
That was how much it beat the previous record, the total height was 143,256 metres.
I understand that HaD is based in the US, but I wonder what the percentage of readers from SI countries is. They should know…
I’m based in the US and use both metric and imperial fluently, metric is just too tempting for ease of use when you’re doing a lot of building and measuring. Or working on a imported machine. It’s funny, when I go to Europe and mention things in SI they say they have no idea what that means and ask me for the metric, and they expect I am the same way about their system, but many Americans who build things are fully accustomed to both
We all love Slovenia, but why would their readership matter?
;-)
Even though I don’t particularly like imperial units as a European, aircraft altitude is usually expressed in feet, specifically in hundreds of feet. This rocket reached FL4700, far above the usual FL500 where aircraft typically cruise.
They should really implement a feature on the site where when you hover over a measurement it auto-converts it to either the SI or metric alternative.. Just an idea.
Also if it’s 470,000 feet you may as well say 89 miles or 143 kilometers. It’s a bit like measuring architecture in millimeters at that point. Definitely broke the Karman line easily
Or HaD readers should be able to do it instinctively. It isn’t hard to remember a couple simple ratios. (It would be nice if people quit calling American Customary and ANSI values “imperial”. They are not the same.)
The now dysfunctional U.S. Military needs this Aftershock II hypersonic missle built by undergraduate students at USC more than anyone! Crate it up then call them and tell them where to pick it up.
Please, I beg you! “hypersonic” is one of the most misused words of the decade… >.<
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B^)
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@moeb said: “Please, I beg you! “hypersonic” is one of the most misused words of the decade…”
“The 14-foot, 330-pound rocket broke the sound barrier within two seconds, reaching hypersonic speeds of Mach 5.5—around 3,600 mph.”
Misused word? Where?
Yeah but this rocket is actually capable of it, so it should bear the title in order to combat the many inappropriate uses of the word. Although I wonder if it reaches that speed in atmosphere, or if it is measured after it breaks the Karman line.. “hypersonic” wouldn’t apply in a soundless vacuum, and moreover there isn’t anything up there which doesn’t move at those speeds…
Please, I beg you! “hypersonic” is probably the most misused word of the century and does not apply at all here…
Wikipedia has “hypersonic” as more than Mach 5. This rocket hit Mach 5.5. How does it not apply?
Yes it’s “hypersonic”. No it’s not the kind of “hypersonic” that militaries are talking about. Hypersonic in a mil context refers to air breathing cruise missiles or glide vehicles, something which does not follow a ballistic trajectory. It implies “difficult to detect and intercept”. Ballistic missiles aren’t referred to as hypersonic. Minuteman III reaches Mach 23 but it’s simply an ICBM.
Ah, those are good points. An ICBM is clearly “hypersonic” if we simply measure its speed during re-entry, but wouldn’t be labeled such because “ballistic” is already plenty descriptive. If you’re going for military application, hypersonic is only a helpful distinction if it can reach those speeds inside a thick atmosphere and maneuver as well
Oh yeah good point about re-entry. That “Mach 23” is going down, the Aftershock II going hypersonic straight up is really impressive.
Yep, thats correct. People talk about hypersonics as an invincible military technology but the real deal is maneuvering at hypersonic speeds at low levels. As we have seen in the Ukraine, straight line hypersonics are easily to defend against by most modern air defense systems because their intercept points are easily computed. A computer doesnt care if you are at mach 2 or mach 10, it is just computing an intercept point. In this article hypersonic is correct, it is just that people have applied some kind of super technology to the word hypersonic. Every orbital and most suborbital trajectories are hypersonic.
Are you talking hyperbollocks?
That’s awesome! I worked on the telemetry module for one of RPL’s first launches back in 2006-2007, and it got featured here a few years later: https://hackaday.com/2011/02/20/blasting-off-with-gps/
I’ll just mention that von Braun got his start in an amateur rocket club.
Well done, these people. A very impressive accomplishment.
That is not the positive you think it is….
But but, there are songs devoted to him …
“Once the rockets are up, who cares where they come down?
That’s not my department, ” says Wernher von Braun.
https://m.youtube.com/watch?v=QEJ9HrZq7Ro
Yes it absolutely is. So he also made a few missiles a hundred years ago, when everyone was bombing everything from every direction anyway. So what. I’m sick of this grovelling in the dirt, no more of this
Yes he was just a poor misunderstood soul, who just wanted to play rockets. Lets ignore the slave labour that he used to put them together.
Is this where we are, good guys on both sides…?
Yes. There actually were good people in Germany. I hate to break this to you but your view of history and humanity is childish. And you live off slave labor right now, despite your sanctimony.
I recently heard the story of a young Czechoslovakian man who was good in Physics and “recruited” by the Nazis to work with Werner von Braun. Opposed to Hitler’s government, he sabotaged some of the experiments he was tasked to do. His “work” was discovered, and he was shot.
Knowledge and technology is spreading fast. I sure hope we all can get our collective ideals on some sort of convergent path, because videos like this make me think, “GREAT!” and “OH NO!” at almost the same time.
…So you think amateur rocketry is impressive yet too scary, and that there should be some massive global centralization of authority to overlook all of it and every tinkerer should be beholden to it. No thanks, that would stifle everything. We don’t need the entire universe to be the EU
Really cool achievement, but I hate tech stories with no details. What was the heat resistant paint that they used? Where the fins metal with titanium nitride coating, or what?
At least you now know what was accomplished and by whom!
Further information regarding this rocket 🚀 is left as an exercise for the student.
B^)
I did enjoy the tiny detail that they sent the rocket up with silver fins but they came back down blue, due to thermal anodization of the titanium coating. Does that happen with titanium nitride? I don’t know my titanium metallurgy very well.
Pretty sure the paint would be an ablative coating. Titanium in an obvious choice for something that needs strength at high heat in aerospace. SR71 was one of the first aircraft to use titanium structures due to the high speeds and heating. Titanium fins were most likely SLS 3D printed for something like this. That is probably easier than attaching a titanium coating because such a thin titanium nitride layer would still conduct a lot of heat to the base material. Just educated guesses but there might be an academic paper to accompany this project.
Good work but probably nothing groundbreaking since solid fuel rockets and titanium manufacturing are pretty well known. Students yes but with USC rocket labs it is probably not too much of a stretch and not exactly what I would call “amateur rocketry”.
Wait, what? Mach 5.5 on a single solid fuel stage, including gravity loss and atmospheric drag? Impressive.
Looking at the specs: Launch 330 lb, Propellant 199 lb = mass ratio 2.5:1 and Isp = 258 (or Ve = 2530 m/s). So, in the absence of air or gravity you’d expect the final velocity to be ln(2.5)*2530 = 2320 m/s (Say, Mach 7).
The 16 second burn time will eat 0.5 of that through gravity loss, and they got 5.5 after punching through 10 tons per square meter of atmosphere (or twice the rocket’s own mass for its cross-section). Not bad. Impressive work.
The long skinny of ballistic coefficients? :-)