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Monday, 25 August 2014

So, were the Russians really the first into space?

  If I’d have been slightly better at maths at school...
  ....I like to think I could have ended up doing something in the aeronautical / spacey engineering sector as a job.  Spaceflight truly is amazing - The thing that is perhaps most remarkable is that a lot of the ground work was done by people like Johannes Kepler and Issac Newton hundreds of years ago with their theories of gravitation, planetary motion and orbits etc.
  I was one of those saaad people who stayed up all night a couple of years ago to experience the absolutely bonkers landing on Mars of JPL’s Curiosity rover. You perhaps don’t believe me but it really was incredibly tense and exciting. It was ‘bonkers’ because of the chosen method of doing it. Very long winded to explain but there’s a short video below. The guys that came up with this are scarily clever, perhaps even borderline doolally but it’s a fantastic example of thinking ‘out of the box’.

Watch "Seven Minutes of Terror"

  In the mid 60’s while NASA was preparing to put men on the moon, they produced a series of cartoon-like films to explain how exactly they were going to do it. Most people have never seen them but there are links to them below. I think they are absolutely brilliant. They make it sound sooo easy but then again, it's hardly rocket science, is it? Er...

Launch Windows 

Lunar Orbit Rendezvous pt1

Lunar Orbit Rendezvous pt2

Atmospheric Reentry

  Anyway, if ever I had to fill a bit of time when I was teaching, I’d ask the students, “Anyone know what the first manmade object in space was?”
  Loads of hands would go up and everyone would say “Sputnik!”
  “Aha,” I’d say, “What if it wasn't? What if it actually might have been a manhole cover?”
  You would then have everybody’s undivided attention for at least the next 15 minutes. The story goes like this….

Operation Plumbbob

  Operation Plumbbob was a series of nuclear tests conducted between May 28 and October 7, 1957, at the Nevada Test Site.   It was the biggest, longest, and most controversial test series in the continental United States.

  Two of the tests, Pascal A and Pascal B were underground tests intended to be of very small yield. They consisted of a 500ft shaft with the weapon at the bottom, sealed with a thick steel plate (or 'manhole cover') weighing nearly a tonne over the top.  Pascal A detonated succesfully but surprised everybody by producing a yield hundreds of times greater than expected!  For the B test, they modified the shaft to accommodate a large concrete collimator - basically a long tube to narrow the beam of rays and particles emanating from the weapon - then bolted the steel cover on top as before.
A Simple Collimator

  The scientist in charge of the test, Dr. Bob Brownlee had an inkling that when the bomb detonated, the concrete used to build the collimator would be instantly vaporized and the resulting pressure in the shaft would blast the heavy steel cap off.  It was only when he did a few calculations that he realized just what could happen - If he was right his figures showed that the steel cover would be accelerated with enough kinetic energy to achieve earth escape velocity. What they’d built was essentially a humungous space cannon!

  So convinced was he that he had a high speed camera trained on the cover shooting at 1000 frames per second so he could see what happened to it.

  On the morning of 27th of August 1957 Pascal B was detonated. As with the previous test, the weapon gave a much higher yield than expected and, sure enough, inspection of the test site afterwards revealed absolutely no trace of the 900kg steel cover.
 However, it was only when the film from the high speed camera was developed that it became clear what had happened to it. The force of the blast accelerated it so quickly that it was caught on the film for just one blurry frame post-detonation. The speed necessary for it to leave the field of view in just 1 millisecond was around 41 miles per second.
  The manhole cover had achieved six times earth escape velocity and was never seen again. As to where it went, well….

  I’d love to think it made it all the way. But realistically the aerodynamic heating of the atmosphere at such a low altitude and insane velocity must surely have at least partially vaporized it – it’s sort of like a backwards shooting star or spaceship reentry.

  Some of it might have made it though, in fact recent calculations have suggested that any fragments would have been blasted into space in a long looping solar orbit. Perhaps one day it’ll come back for a visit and we’ll crash into it to make a spectacular shooting star. It might even survive reentry and crash back to the ground. Now that’d be a turn up!!

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