Monday, July 21, 2008

Come on out, boy, it's WINDY!

So the other day I came upon the realization that I need to be a little more aware of my surroundings sometimes. Why? Because I often seem to overlook things that are painfully obvious- for example, did you know that the very same base I've called home the past several weeks is also home to the world's largest wind tunnel?
I mean, you think I would've picked up on this. It's huge! To be fair though, I'd only ventured to this part of the base once before (it's in a gated research area) and I'd only been there once, ahem, late at night, when I wasn't on a mission to learn the trivia of the area. But there was a tour of said wind tunnel a few days ago advertised to all the science interns associated with NASA Ames, so it made sense to check it out.

By the way, it goes without saying that they still test some military stuff here so you aren't allowed in if you were a forgein national. But then this is a bit loose, as I saw a pack of German guys get let in and they had no problems with pictures getting posted on the Internet-
So this is what the world's largest wind tunnel looks like inside. How big? Well wind tunnels are referred to by their dimensions in the industry and this is the "80 by 120", meaning it's 80 feet by 120 feet (sorry I can't recollect how long). No word as to why the industry doesn't use metric.

A bit of perspective in this picture: it was taken from the very front near an air grate in the front, and there were two side vents where the air comes in from. As the end result here, the top wind speeds in the tunnel of 300 knots. In fact, when originally built the air flow heading out was hurling rocks and boulders towards a nearby gate, so they needed to change the design. They ended up just directing the air upwards- sure, a plane caught in the draft would immediately crash, but they can call up the FAA when doing a test so no worries (and this is also why, by the way, I live in a nationally restricted airspace!).
While we were visiting, the test set up to occur right after us was an important test for the next generation Mars rovers. Currently the method of choice to land on Mars involves a parachute landing (see video), and the place to do it is here. In fact, there was a great Nova episode awhile back on building the Mars rovers Spirit and Opportunity- they came to the 80x120 to test them, only to discover frightfully close to the launch window that they didn't work and would result in a rover smashed on the surface. Oops... luckily the mistake was figured out, and here's a picture of it deployed in the tunnel courtesy NASA-
This time around they showed up with plenty of time to spare and the first tests went off without a hitch from what I hear (launch is September 2009). One interesting detail though: whereby the Mars rovers were, say, a golf cart in area, the next Mars rovers are going to be the size of a minivan. Here's a picture just because I happen to have one-
To take into account the large mass, of course, you need a bigger parachute. The current parachute diameter is a whopping 60 feet across, meaning there's only ten feet of clearance on either side. Really not that much... and, of course, this means Mars missions after this one will need to think up a new landing method if we keep doing rovers. I'm pretty sure your method is deemed unmanageable when the world's largest wind tunnel can no longer accommodate your size.

As you can imagine, though, a lot of stuff has been tested here over the years. In fact, outside is a miniature park of old airplane models tested in the wind tunnel- a lot look like they were headed to the junk heap but no one could be bothered to take them, but this one caught my eye-
They tested the Space Shuttle here! Ok, to be fair this is a mere model of the Shuttle a third of the size and made of wood, but it's still pretty.

Anyway, I just wanted to share all this because it really was a pleasant surprise to find such a national treasure in my backyard, and it's always fun to have a connection to the NASA missions. You get loads more nerd bragging rights that way.