That’s exactly where my mind went: Space Elevators. Always with reverb in my head, b. Space!!! Elevators!!!
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No, it didn’t reach orbit and wasn’t meant to. They said it reached “tens of thousands of feet” but this was just their first shot with the system, not at full speed.
And you can’t insert an object into orbit by shooting it straight up. You have to shoot it at a low angle, and then when it reaches its highest point it must use a rocket to circularize the orbit or it will come right back down.
“Tens of thousands of feet” is a few miles, nowhere near the edge of space at a nominal 50 miles.
I want to know how they’ll prevent the launched satellite from immediately burning up. To get to orbit, its launch velocity must be that of a meteor.
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So Q-Max occurs at the instant of release, not several thousand feet up where the air is thinner. That being the case, why not just launch the vehicle from a giant gun ala Jules Verne? We already launch “smart shells”.
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They could just shoot it.
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This and other questions are answered on the FAQ section of their site. (Unfortunately not viewable on mobile devices)
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I was going to mention that. Interesting idea that didn’t pan out. The guy who was in charge of that was trying to build a gun that could shell neighboring countries for Iraq, though it probably would not have worked.
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Yeah, were I an engineer working on a new launch system I’d try to avoid following too closely in the footsteps of Gerald Bull.
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This video seemed to have more analysis.
Personally I was going to go with a pulley, chains and weights down some enormous hole in the ground. However I and not doing that or evil billion dollar residences … yet
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You noticed that too? Let me know if you spot any POC…
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The forces are actually much, much more brute. Rockets are comparatively gentle because they accelerate continuously. With this system, all the acceleration is in a single impulse. The object is decelerating from the moment it launches so it needs enough delta V to hit escape velocity before it decelerates too far.
10,000 Gs worth of impulse, they claim, which is probably conservative. The general consensus among my aerospace industry friends is that thing won’t ever fly real hardware. Their claims of being able to proof satellites against 10,000+ Gs are optimistic at best.
But hey, it’s cool that people are trying new things! I’m all for crazy ideas.
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They are nasty, brutish, and short!
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It’s certainly anti-intuitive that mechanical hardware like the reaction wheels, fuel system components, etc could be built to withstand that, but time will tell. I’m a mechanical engineer but am still sometimes surprised to see designs that really don’t look like they should work but still do.
As they already have a couple of the world’s fastest centrifuges built they should be able to do a lot of hardware testing on the ground to confirm if can withstand those loads. Like I said above, I was surprised to read that they subjected an off-the-shelf smartphone to those loads without damage.
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Yes! Scott has a great analysis and he does a lot of ballpark calculations to give this a really in-depth feel. He even mentions Project HARP and rail/coilgun alternatives. My biggest takeaway was the fact that it can build the kinetic energy needed over roughly an hour through electric motors rather than the intense controlled fireball of a first stage ascent rocket engine. Good stuff!!!
I want to know how they’ll prevent the launched satellite from immediately burning up. To get to orbit, its launch velocity must be that of a meteor.
Not actually a new problem. The Nike-X ABM system of the 1950s used ground-launched Sprint missiles that went from zero to Mach 10 in five seconds. The atmospheric heating on the missile was dissipated with an ablative shield.
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Part of Gerald Bull’s HARP programme was called the Martlet 4 - a gun-launched satellite:
http://www.astronautix.com/m/martlet4.html
(The Martlet project was later disinterred and used as a cover for Iraq’s supergun).
After HARP was cancelled, Bull went to work for apartheid South Africa and designed the two most accurate and long-range artillery pieces in the world which helped build that country’s arms industry into a serious world-power.
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How do you figure the acceleration is a single impulse? The projectile is accelerated gradually in the centrifuge, then it’s ‘let go’ (no longer has a force to the centre of centrifuge), and starts to decelerate (gravity and air resistance). The lateral force is the greatest worry here, but impulse isn’t (by my understanding).
Impressive ambition. But they ought to build it near the equator to take advantage of higher inherent kinetic energy and at significant height, like atop Mt Kilimanjaro, for thinner air. Since the thing will be exiting at mach 6+, the air resistance at lower altitude translates to enormous heat & drag. Then of course there’s also the unholy sonic boom…
Conventional rocket launches aren’t exactly quiet affairs either. They claim that the shockwave of the boom will be directed upward (makes sense) as opposed to the noisy end of a conventional rocket, which is generally pointed down.
The video I watched from the company acknowledges the issue of the launch release creating an imbalance in the spinner / centrifuge. If they don’t send an opposite mass off the other side (and they don’t say that’s the plan) it’s a huge change in balance / rotational inertia, that needs to be countered in a time on the order of a microsecond.
I don’t know how they would do it, and they don’t say, but the fact their test model didn’t rip itself to pieces indicates they have something. Scaling it up won’t be easy (by their own claims) but … well, that’s what R&D is about.
The rotating acceleration isn’t a single impulse. But releasing the mass to fly upwards creates a huge imbalance that needs to be resolved very quickly to avoid damage to the machine. THAT will require a very large, fast impulse.
