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Comment: Re:fall to Earth (Score 4, Informative) 122

by qvatch (#45378579) Attached to: GOCE Satellite Is Falling To Earth But Nobody Knows Where It Will Land
and http://www.spacesafetymagazine.com/2013/09/14/european-satellite-goce-uncontrolled-reentry/ his will be the first uncontrolled reentry of an ESA satellite since Isee-2, in 1987. Unfortunately, it will not be the last, considering that the bus-size Envisat’s altitude is gradually decaying in Low-Earth Orbit without control. According to ESA, up to 25% of GOCE’s mass will survive the extreme reentry conditions to fall to the ground. However, the risk for populated areas is very small since the majority of the Earth is covered by oceans. “The major part of what survives to the surface will be the core instrument,” says Dr. Floberghagen. “From the original mass which we have now in space, we have estimated that about 25%, about 250 kilos, will reach the surface, and these 250 kilos will be distributed over between 40 and 50 fragments.” The fragments that survive will hit the ground in a 900 km long footprint. The reentry will be a good test for debris monitoring systems and fragmentation models.

Comment: Re:fall to Earth (Score 5, Informative) 122

by qvatch (#45378571) Attached to: GOCE Satellite Is Falling To Earth But Nobody Knows Where It Will Land
Some, but not all of it. http://www.spaceflight101.com/goce-re-entry.html : With its fins and aerodynamic shape, GOCE will maintain a stable position in orbit as it approaches entry. During entry, the spacecraft will likely remain in that position for the initial phase of re-entry until it breaks up. Following the destruction of the spacecraft, most of its components will harmlessly burn up in the atmosphere. However, it is known that about 20 to 40% of a re-entering satellite's total mass reach Earth's surface. Dense components of satellites usually impact 800 to 1,300 Kilometers downrange from the Orbital Decay Point. Their journey back to Earth is strongly influenced by atmospheric properties like crosswinds that play a major role during atmospheric descent.

Comment: Re:Good idea (Score 1) 147

by qvatch (#43676999) Attached to: New 'Academic Redshirt' For Engineering Undergrads at UW
it depends what you call passed. 50%, 65%, 80% (here, that's the min undergrad, honours, grad grade to "pass"). Passing means you know enough to do that material, not that you understand it well enough to apply it without effort while learning the next level, so if you stopped there you could be considered to know the material.

Comment: Re:$4.30 MSP430 Launchpad for starters (Score 2) 228

by qvatch (#42722575) Attached to: Ask Slashdot: Best Electronics Prototyping Platform?
I started with arduino, and I had no microcontroller experience. The community, examples from the absolute ground up, and vendor (sparkfun, adafruit, etc) support is excellent. It all makes for a really enjoyable experience. Digikey and mouser get you parts fast. Ebay and random asian websites get you parts slow but cheap. If you want graphics (eg. TV, or monitor) though, best go with the pi. A pi costs less than an arduino graphics shield. Ethernet is doable at least.

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