By Soulskill from Slashdot's what-does-roe-v-wade-say-about-this? department
writes: The next great leap in human spaceflight is a manned mission to a world within our Solar System: most likely Mars. But if something went wrong along the journey — at launch, close to Earth, or en route — whether biological or mechanical, would there be any way to return to Earth? This article is a fun (and sobering) look at what the limits of physics and technology allow at present.
If you're interested in a hard sci-fi, near-future look at how a catastrophic Mars mission might go, you should read an excellent novel called The Martian
by Andy Weir
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By Soulskill from Slashdot's i-demand-a-recount department
New submitter Raymondware
sends an update to last week's news
that NASA had awarded contracts to Boeing and SpaceX to provide rockets for future manned spaceflight. Now, one of their competitors, Sierra Nevada Corp, has announced it will launch a legal challenge to the contracts
. The company claims the government is spending $900 million more than it needs to
for equivalent fulfillment, and they're demanding a review. They add,Importantly, the official NASA solicitation for the CCtCap contract prioritized price as the primary evaluation criteria for the proposals, setting it equal to the combined value of the other two primary evaluation criteria: mission suitability and past performance. SNC’s Dream Chaser proposal was the second lowest priced proposal in the CCtCap competition. SNC’s proposal also achieved mission suitability scores comparable to the other two proposals. In fact, out of a possible 1,000 total points, the highest ranked and lowest ranked offerors were separated by a minor amount of total points and other factors were equally comparable.Read Replies (0)
By Soulskill from Slashdot's causing-frustration-is-a-valid-design-strategy department
An anonymous reader writes "The Z-80 microprocessor has been around since 1976, and it was used in many computers at the beginning of the PC revolution. (For example, the TRS-80, Commodore 128, and ZX Spectrum.) Ken Shirriff has been working on reverse engineering the Z-80, and one of the things he noticed is that the data pins coming out of the chip are in seemingly random order: 4, 3, 5, 6, 2, 7, 0, 1. (And a +5V pin is stuck in the middle.) After careful study, he's come up with an explanation for this seemingly odd design. "The motivation behind splitting the data bus is to allow the chip to perform activities in parallel. For instance an instruction can be read from the data pins into the instruction logic at the same time that data is being copied between the ALU and registers.
[B]ecause the Z-80 splits the data bus into multiple segments, only four data lines run to the lower right corner of the chip. And because the Z-80 was very tight for space, running additional lines would be undesirable. Next, the BIT instructions use instruction bits 3, 4, and 5 to select a particular bit. This was motivated by the instruction structure the Z-80 inherited from the 8080. Finally, the Z-80's ALU requires direct access to instruction bits 3, 4, and 5 to select the particular data bit. Putting these factors together, data pins 3, 4, and 5 are constrained to be in the lower right corner of the chip next to the ALU. This forces the data pins to be out of sequence, and that's why the Z-80 has out-of-order data pins."Read Replies (0)
By timothy from Slashdot's everyone-has-their-reasons department
An anonymous reader writes "Open source operating systems vulnerable to the Shellshock bug have already pushed two patches to fix the vulnerability, but Apple has yet to issue one for Mac OS X. Ars Technica speculates that licensing issues may be giving Apple pause: "[T]he current [bash] version is released under the GNU Public License version 3 (GPLv3). Apple has avoided bundling GPLv3-licensed software because of its stricter license terms....Apple executives may feel they have to have their own developers make modifications to the bash code.""
It's also worth noting that there are still flaws with the patches issued so far
. Meanwhile, Fedora Magazine has published an easy-to-follow description of how Shellshock actually works
. The Free Software Foundation has also issued a statement about Shellshock
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By timothy from Slashdot's more-faster-cheaper department
An anonymous reader writes "A research team from the University of Texas and a German nanotechnology company have published a paper which describes a major milestone for the future of graphene-based computing – the reliable production of wafer-scale graphene measuring between 100 and 300mm, suitable at last for integration with 'traditional' materials in computing. The research team was able to manufacture 25,000 graphene field-effect transistors from lab-produced graphene film on a polycrystalline copper base. Team research leader Deji Akinwande said: 'Our process is based on the scalable concept of growing graphene on copper-coated silicon substrates...Once we had developed a suitable method for growing high-quality graphene with negligible numbers of defects in small sample sizes, it was relatively straightforward for us to scale up.'"
(Original, paywalled paper
is at ACS Nano
.)Read Replies (0)