Daily Archives: July 23, 2009

What’s frangible about a frangible link?

One of the tests run today was a test of the helicopter / cable / winch system.  Everything between the winch and the helicopter is referred to as the ‘cable assembly’.  This includes not only the steel cable which the climbers will ascend and descend, it also includes things such as hooks, shackles, load cells, etc.  If any of these components fail and causes a breakage or separation of the assembly, it is referred to as a ‘cable separation event’.

During the testing today of the helicopter / cable / winch system, a “cable separation” event occurred.  One of the components in the cable assembly is a frangible link and it was included to protect the helicopter in case a specified load on the cable assembly was exceeded.  That link separated today during testing.  Either the link failed to hold to the required load or else the load exceeded the link’s rating.  There might be a third possibility, but I can’t think of what it might be offhand.

The picture thumbnail shows the link.  This link is in the assembly with other components above and below it.  The plug, shown in front of and to the left of the link, pulled out of the link – it should only do this when its rating is exceeded.  As I wrote earlier, either the load did exceed the rating or else the link failed and separated prematurely.

Obviously, there will be testing and analysis to done to determine why this all happened, just as happened after the pulley failure in the previous test round.  Stay tuned to this blog or the official website of the Space Elevator Games to keep up-to-date.

Incidentally the redesigned pulley performed flawlessly and this looks like a solved problem.

One other thing which should be noted is that a ‘cable separation event’ was one of many contingencies which had been previously thought of and a procedure designed for.  The NASA person in charge of this operation immediately called this procedure into effect and executed it.  Procedures are useful only when they are followed and this one was followed promptly and correctly.

Laser testing continues to go well and will conclude tomorrow (Friday).  The TRUMPF laser continues to perform nominally and the remaining teams are taking full advantage of it.

(Click on the picture thumbnail for a larger version of the picture)

King of the Road

This is more like it!  When USST showed up for the first round of testing, there were only four of them.  I was quite disappointed, expecting their usual army.  For this round of testing, however, they are here in force, 13 in all.

And they’ve come in style – look at the picture of that truck!  Yes it’s a rental, but it’s easily the coolest vehicle I’ve seen so far in this competition.  The truck is a Chevy (with a Santini paint job) and is a monster.  They are using it to pull the motor home they have with them – I think it could pull a lot more.  I asked them if they would wash it for me so I could get a good picture of it, but they declined.  Spoilsports…

When I visited their work area yesterday, their climber was mostly assembled – you can see it here.  However, you’ll note that they have nothing on there to hold payload (at least I didn’t recognize anything that could be used as such).  When I asked what they were going to use (last year they had some tubes mounted to their climber), I just got some smiles and an offhand comment about “we’ll have something”.  I’m sure they will.

And, it looks like from this picture that they’ve been putting in some long hours (as everyone involved with the Games has)…

(Click on the first or last picture thumbnail to see a larger version of the picture)

We’re now live

NASA has now got their live TV coverage from the lake-bed working.  It was actually working about an hour ago, but I logged on in an attempt to clean up a screen title and screwed things up.  Fortunately the NASA guys are pretty sharp and fixed it.  Sorry guys…

The direct link to see us is http://www.ustream.tv/channel/space-elevator

You can also go to http://www.ustream.tv/segames and then click on “Go to Show Page”.

You must have the Flash Player installed to make it work.

Enjoy! (and thanks NASA!)

Below is a screen shot of the uStream feed from a few minutes ago…

Day 3 begins…

I spent 8 years living and working in Saudi Arabia.  As anyone who lives in the desert will tell you, the sunrises are spectacularly beautiful.  This picture is of sunrise over Edwards Air Force base this morning…

In the sunrise picture, you’ll note a garbage can in the foreground labeled “FOD” – I’ve included a close-up picture of this also.  FOD is an acronym for one of two things; the “FO” stands for “Foreign Object” while the “D” can stand for ‘debris’ or ‘damage’.  If you find an object on the desert floor out on the lakebed, you pick it up and put it in a FOD can (or throw it away or something – just get it off of the lakebed).  Airplanes land there and the last thing they need is any “Foreign Object Debris” to cause grief.  If a plane is damaged by some such object, than it is said to have been “FODDED” – “Foreign Object Damage”.

Great care is taken here to prevent FOD.  When vehicles come off of the lakebed and cross the runways to get back to the hanger (or wherever they’re going), they are required to do a FOD check before they cross the runway.  You stop the car and go around and check all the tires for rocks and other debris.

FOD is a big deal here and rightly so.  Anyone who doubts that a small piece of metal or other debris could be harmful to an aircraft only need remember Concorde Flight 4590 – a flight that crashed due to picking up a piece of metal on takeoff.

[youtube]http://www.youtube.com/watch?v=Qid2s89OfZU[/youtube]

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(Click on a picture thumbnail to see a larger version of the picture)