Did the United States Beat Sputnik into Space?
Those of us with an interest in the early days of the space race — won by Sputnik 1 in October 1957 — might need to broaden our disciplines a bit to get the whole story. It turns out that the race might have actually been won two months earlier, by the United States, with an entrant from outside the space program. Its name was Operation Plumbbob.
For six months in 1957, Operation Plumbbob put 29 thermonuclear devices to the test in the Nevada Test Range. They were the most varied in the program’s history; all sorts of devices, fired in the air, on the surface, underground, at pigs, near soldiers, and at all kinds of structures. Two of them were particularly interesting. Pascal-A and Pascal-B, on July 26 and August 27, were detonated at the bottom of 500-foot vertical shafts. Both shafts were covered with great heavy steel lids, some four inches thick and weighing some 900 kg.
Pascal-A was supposed to have a yield of 1-2 pounds, but somebody got his slide rule wrong: the true yield turned out to be 55 tons, about 50,000 times greater than expected. For Pascal-B, they added a concrete collimator about halfway down the hole. Once again, the yield was far more than expected, moreover by about six times as much: 300 tons. The concrete collimator was (obviously) instantly vaporized by the explosion, and the massive gas expansion from the concrete turned the shaft into a compressed-gas cannon. That giant metal lid was launched straight up, at what was estimated to be six times escape velocity.
From the March 1992 issue of Air & Space magazine:
Every kid who has put a firecracker under a tin can understands the principle of using high explosives to loft an object into space. What was novel to scientists at Los Alamos was the idea of using an atomic bomb as propellant. That strategy was the serendipitous result of an experiment that had gone somewhat awry.
Project Thunderwell was the inspiration of astrophysicist Bob Brownlee, who in the summer of 1957 was faced with the problem of containing underground an explosion, expected to be equivalent to a few hundred tons of dynamite. Brownlee put the bomb at the bottom of a 500-foot vertical tunnel in the Nevada desert, sealing the opening with a four-inch thick steel plate weighing several hundred pounds. He knew the lid would be blown off; he didn’t know exactly how fast. High-speed cameras caught the giant manhole cover as it began its unscheduled flight into history. Based upon his calculations and the evidence from the cameras, Brownlee estimated that the steel plate was traveling at a velocity six times that needed to escape Earth’s gravity when it soared into the flawless blue Nevada sky. ‘We never found it. It was gone,’ Brownlee says, a touch of awe in his voice almost 35 years later.
The following October the Soviet Union launched Sputnik, billed as the first man-made object in Earth orbit. Brownlee has never publicly challenged the Soviet’s claim. But he has his doubts.
I first heard about this from reader Simon Spooner, who emailed me about it. He offered his own thoughts on the likelihood of this happening:
I agree that the although steel plate cap may have initially been accelerated past escape velocity (> 11.2 Km/s), given its unaerodynamic shape and the fact that it was travelling through the dense part of our atmosphere (rockets don’t approach escape velocity until very high altitude where the atmosphere is much thinner) it would have acted like a meteor in reverse (i.e. from the ground upwards rather than from the sky downwards) and it would have burned up like a meteor that never reaches the ground (meteors are often largely made of iron, just like the steel plate cap). If it didn’t completely burn up and gravity returned some of it to earth, it would have travelled quite some distance, necessitating a large search area, and the fast falling remains would have probably just buried on impact deep into the desert soil anyway. This might explain why nothing of it was found.
My guess is that the steel plate would fare even worse than Simon supposed: that a blast of such speed would cut a donut hole in the plate before it would lift it off the ground. But I really don’t know. I’d be shocked if it could survive the physical and aerodynamic stresses enough for any significant sized piece of it to make it into orbit.
Here are a few links if you’d like to read more about this. Note that there seems to be some confusion between Pascal-A and Pascal-B; some sources seem to have details between the two transposed, and it’s not always clear which articles are sourced from interviews with guys remembering stuff, and which are based on documentation. Consequently some of my details above may well be inconsistent with what you find on your own.
http://nuclearweaponarchive.org/Usa/Tests/Plumbob.html#PascalB
Wow, that’s amazing.
Getting it up would not have gotten it around. President Ike wanted a private enterprise satellite and ordered parts made to mate Army military rockets destroyed. Von Braun hid them. After Sputnik, he put the Army parts together to make our first one. Ike took rockets away from the Army then and stayed mad over the government doing it.
This would make a good Mythbusters episode.
-The yield is 5 to 5000 kilotons.
-What do you mean 5 to 5000?!
-Well, we think it’s 5, and then KABOOM!
It’s impossible for something launched from the ground and then affected only by gravity to reach orbit; if it doesn’t escape the planet altogether it will be on some sort of elliptical trajectory that intersects the ground, so not an “orbit” at all.
Of course, the plate would also be affected by the air, but I can’t imagine that the air would manage to affect the trajectory from basically exactly straight up to having a huge horizontal component.
Great, so this thing may be about 30 years ahead of Voyager? Rather than a nice golden LP and anatomical diagram, some alien spacefarers are going to find a manhole cover with “Property of Las Vegas Dept of Public Works” on the back.
PS – This reminds me of the way the humans fight back against the aliens in Larry Niven’s Footfall. Has anyone else read that?
“Pascal-A was supposed to have a yield of 1-2 pounds, but somebody got his slide rule wrong: the true yield turned out to be 55 tons, about 50,000 times greater than expected. ”
The ensuing furor over this mistake is now famously known as the ‘Plumbbob- square rants’.
That’s really funny. I wish we had a picture of the scientists’ faces when that happened.
I still don’t think it would beat Sputnick, since it would have been accidental. There is very little national pride in accidentally blowing out a manhole cover.
It’s all fun and games until somebody loses an eye.
Brian:
Something is wrong with numbers. I cannot imaging that thermonuclear device could yield just 2 pounds even theoretically – “unexpected” 55 tones is not too much either.
The Pascal-A detonation was a safety test that wasn’t intended to actually detonate the ‘physics package’ itself.
How was the velocity estimated? I’m also guessing calculations were done assuming no friction in the atmosphere or in the shaft and a lid which maintained a perfect plug rather than turning sideways and reducing its air resistance. This is just crazy talk. Years ago I was reading the diary of an old friend and he had a bit to say about the space race; there was a lot of frustration over the fact that a proposal for a satellite was continually rejected up until Sputnik was launched – then there was finally some funding for what would eventually be Vanguard. Unfortunately I can’t remember the names of people involved and I doubt the diary still exists; some clueless people cleaned out the guy’s office 20 years ago and threw everything out, including some rare artifacts such as an original Wood diffraction grating in excellent condition.
Hmmm … OK … velocity was estimated from the high-speed camera – but we don’t know the little details and can’t estimate the errors.
As for the lid burning up like a meteor – no it won’t. A large iron object like that will definitely survive. Let’s not forget that 6 times escape velocity is nowhere near the speeds at which meteors (and meteorites) plunge into our atmosphere, and if we take a quick look at spacecraft like the Space Shuttle or Soyuz, they heat up far more on entry than on exit and they’re still nowhere near a meteor’s speed.
Even at 6x escape velocity we would need to consider aerodynamic resistance – is there anyone out there with the appropriate models set up to do so? I also have no faith in the accuracy of claims like “it shot straight up”. However, it should be possible to make a variety of estimates and get some idea of whether it is possible for that lid to have at least achieved suborbital flight given favorable but realistic conditions.
Back then, diffraction gratings were made of wood :-p
Vanguard was made by GM and never worked till long after Sputnik. I well remember the Vanguards burning. It was the private enterprise satellite. Ike had promised to stop the government from doing things so private enterprise would do it. It has never worked well. The DD had people going to the Army launches to make sure they did not put a 3th stage on and make a satellite. After Sputnik, Von Braun leaked that the Army could do it, so Ike had to let him. He used the parts Ike ordered dumped and made it in one. And Ike hurt the Army over it. He gave rockets to the Air Force.
‘Won’ is relative.
The winner isn’t the first runner off the starting line, but the first over the finish line.
Using that criteria, the USA gets the gold medal for winning the space race.
@Greisha (#9):
That was my thought, as well. The first link Mr. Dunning posted has a pretty good explanation, though. It was a “safety test” of part of the detonation system, not intended to be a full scale thermonuclear detonation – but it turned out rather more energetic (but still far short of a full scale detonation in the multi-kiloton range).
That link also has (what appears to a layman like me to be) a pretty good, brief analysis of the physics of the flying manhole cover, and why it almost certainly didn’t actually leave the atmosphere.
Actually, I’m pretty sure the cover survived being launched from it’s position on top of the shaft: The high-speed camera caught a shot of it in the air.
However it only has one frame of it airborne, by the next frame the cover had already exited the top of the shot. This is why there are no solid numbers for its launch speed: There is a minimum, (crosses the shot in two frames), a maximum, (blast energy), and a theoretical calculation.