typodupeerror

## NASA's Juno, Armored Tank Heading For Jupiter185

coondoggie writes "When it comes to ensuring that its upcoming Juno spacecraft can survive its mission, NASA is surrounding the spacecraft's electronic innards with titanium to ward off mission-threatening radiation. Juno's so-called radiation vault weighs about 200 kilograms (500 pounds), has walls that measure about a square meter (nearly 9 square feet) in area, about 1 centimeter (a third of an inch) in thickness, and 18 kilograms (40 pounds) in mass. About the size of an SUV's trunk — encloses Juno's command and data handling box, power and data distribution unit and about 20 other electronic assemblies, according to NASA."
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## NASA's Juno, Armored Tank Heading For Jupiter

• #### Re:Unit conversions (Score:3, Interesting)

on Wednesday July 14, 2010 @12:25PM (#32903406) Journal

I understand the math. I was being sarcastic, actually. yeah, I know it doesn't communicate well over the internet. The point is that 1 square meter is considerbly more than 9 square feet. The actual article is poorly written. If the topic weren't so terribly interesting, I wouldn't have wasted my time. However, I would have linked directly to NASA's page instead of the hack that wrote the article.

• #### Summary bad, but not as bad as you might think (Score:5, Interesting)

on Wednesday July 14, 2010 @01:18PM (#32904210)

The article links to some kind of 'ooh, look at me' article instead of NASA's own page on Juno.

Juno Armored Up to Go to Jupiter [nasa.gov]

Each titanium wall measures nearly a square meter (nearly 9 square feet) in area, about 1 centimeter (a third of an inch) in thickness, and 18 kilograms (40 pounds) in mass.

Not exactly good maths there, so probably a PR piece from a 'journalist'.
9 foot^2 = 0.84 m^2 [google.com]. Could be correct, though I wouldn't use "nearly" for something that far off. And it's impossible to tell if the walls are really 9 foot^2 and they just made a very rough guestimate of the metric equivalent.

1/3 inch = 0.85 cm [google.com]
Again, that could be right. It might be exactly 1/3rd inch and they guestimated that to about 1 cm. But it's still 15% off.

40 lbs = 18.14 kg [google.com]
And then you hit something where the weight is actually correct. But since they've messed up that much on the other two, we now don't know if it's exactly 40 lbs or exactly 18 kg.

Hell, we don't even know if the NASA guys who wrote this are incompetent or not. Well, we know they're incompetent, we even know how much (about 15%).

However, the NASA page seemingly being written by an 8-year-old with a bad understanding of units, doesn't really justify linking to an article that is essentially a copy of NASA's page, and especially not when there is no attribution or links to the original article.

• #### Re:Unit conversions (Score:3, Interesting)

on Wednesday July 14, 2010 @01:56PM (#32904710)

It was a long, long time ago, but if I recall correctly Mars Polar Lander was a "Class C" project (meaning that QA requirements weren't very strict, and it didn't have to pass the much more stringent requirements like dual-fault tolerance, etc., that are enforced for class A and class B projects). The breadboard for the meteorology subsystem was a one hundred dollar 8031 CPU board purchased off the Internet from some company whose name I forget. The project couldn't even afford an In Circuit Emulator for the meteorology subsystem CPU. :-(

Life would be so much easier if we could just look at the source code. -- Dave Olson

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