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## 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:2, Insightful)

on Wednesday July 14, 2010 @01:09PM (#32903120) Homepage Journal

I learned many years ago that converting units for the metrically challenged does them no service. They need to learn to convert them themselves, so they can speak to the rest of the world in units we all understand.

• #### Is there an engineer or scientist in the house? (Score:5, Insightful)

on Wednesday July 14, 2010 @01:37PM (#32903610)

"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 "

I notice a few issues in this description, which also appears in the article. Some fact-checking might be in order.

How can a single thing be 200 kg, and also be 18 kg? You would think that a single thing would have only one mass.

Then, of course, a square meter is slightly more than 10 square feet.

How can a single square meter of material be made into all six sides of a box the size of a SUV trunk, without slicing it into thinner sheets. A square meter might make one side of such a box, but not all six. If all six sides of a cube total 1 square meter, each side would be about 40.8 cm square. Of course, the box doesn't have to be a cube, but the sum of the areas of the six sides still cannot exceed the total of the material.

Titanium has density of 4.5 g/cm^3. So a 100x100x1 cm piece of it would be 45 kg, not 18 kg.

• #### Re:Unit conversions (Score:1, Insightful)

by Anonymous Coward on Wednesday July 14, 2010 @03:00PM (#32904776)

Yes but the imperial system is the IE6 of the measuring system world.

• #### Re:1.8 g/cm^3? What material is that? (Score:3, Insightful)

on Wednesday July 14, 2010 @03:27PM (#32905134)

It's made from the journalist's incompetence.

• #### Re:Summary bad, but not as bad as you might think (Score:3, Insightful)

on Wednesday July 14, 2010 @04:11PM (#32905730) Homepage Journal
Pedantic much? Or did you just miss the fact that the engineers working on the project at NASA, when talking to the reporters/PR people, realized saying, "0.84 meters squared, 0.85 cm thick, and approximately 18.14 kg," wouldn't have told them diddly squat about what the actual dimensions of the hardware This is a NASA mission. Thus, it is going to generate a lot of publicity/press in the United States. Most folk in the United States think in terms of feet and inches. Using numbers like 9 square feet, and one-third of an inch give dimensions that people can visualize easily while reading a press release (I can look at my size 12 foot and say, "Well, it's about three of those long on one side). Using point something something centimeters or meters is just going to make people sit around and say, "Okay, a meter is a bit longer than a yard, what's 85% of a meter? Oh wait, it's square meters we're talking about? Screw this, I'm going to go watch the new Twilight movie instead."

When it comes down to it, if an engineer is going to be bragging about one of their projects to the press, they are going to use some off-the-cuff estimates, "Yeah, it's about a third of an inch thick," rather than the specific dimensions they used in their design because they realize that people don't know, or care, what 0.8495672331 cm looks like. Similarly, the press realizes it needs to report units that can actually help people visualize since the majority of the readers are not going to be sitting their with engineering paper and a ruler trying to do some kind of calculations/estimates with the information. Thus, I would say that both the press, and the engineers, did their job just find by, essentially, saying something along the lines of, "It's about this big, if you want to visualize it."

So all that, "I wouldn't call a 15% discrepancy 'close'" mumbo jumbo you just warbled out is nothing more than you spouting an overly pedantic analysis of a, "Hey look at this cool piece of hardware," article. You need to find yourself a hobby other than posting to slashdot if you have nothing better than that to do with your spare time.

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