Many satellites rely on thrusters for station keeping and orbital adjustment. These are tiny and sip fuel, but it adds up - a geosynchronous communication satellite is usually about half fuel making it much more expensive to orbit. Boeing has a new class of communication satellite that uses xenon ion engines for the task. They don't use much Xenon - it is easy to carry a few decades worth - and the satellite weight is cut in half allowing launch costs to drop dramatically.
The chairless chair, which Audi has further developed together with a Swiss start‑up company, is an exoskeleton that is worn on the back of the legs. It is fastened with belts to the hips, knees and ankles. Two leather‑covered surfaces support the buttocks and thighs while two struts made of carbon‑fiber‑reinforced plastic (CFRP) adapt to the contours of the leg. They are jointed behind the knee and can be hydraulically adjusted to the wearer’s body size and the desired sitting position. Body weight is transferred into the floor through these adjustable elements. The chairless chair itself weighs just 2.4 kilograms. Dr. Stephan Weiler, the doctor responsible for ergonomic workplace design in Audi’s health department: “The chairless chair is a clear demonstration that Audi places priority on attractive and well‑designed workplaces. This construction reduces the stress and strain on our employees’ knees and ankles in an ideal manner.”
While working, employees wear the chairless chair like a second pair of legs to provide support whenever needed. For many assembly operations, it allows employees to sit in an ergonomically favorable position instead of standing – even with short working intervals. At the same time, this high‑tech supporting structure improves posture and reduces strain on the legs. Chairs and stools, which are currently used in some assembly operations as temporary aids, become unnecessary. At the same time, Audi hopes that use of the exoskeleton will reduce employee absenteeism for physical reasons. “With the use of the chairless chair, we are continuously improving ergonomics in assembly operations. We also anticipate new applications for colleagues with reduced physical capabilities,” stated Dr. Mathias Keil, Head of Industrial Engineering Methods at AUDI AG.
It is very difficult to perform live testing in the domain of mission control systems. No-one wants to take any risk with an existing, valuable satellite, so it is very difficult to test new procedures, techniques or systems in orbit. The OPS-SAT solution is to design a low-cost satellite that is rock-solid safe and robust even if there are any malfunctions due to testing.
The robustness of the basic satellite itself will give ESA flight control teams the confidence they need to upload and try out new, innovative control software submitted by experimenters; the satellite can always be recovered if something goes wrong.
Achieving this level of performance and safety at a low cost is a challenge. To do this, OPS-SAT combines off-the-shelf subsystems as typically used with cubesats, the latest terrestrial microelectronics for the on-board computer and the experience ESA has gained in operating satellites for the last 40 years in keeping missions safe.
The result is an open, flying 'laboratory' that will be available for in-orbit demonstration of revolutionary new control systems and software that would be too risky to trial on a 'real' satellite. By the end of 2013, over 100 companies and institutions from 17 European countries have registered experimental proposals to fly on OPS-SAT. The design and definition phase of the mission is in progress and due to be completed in early 2014. The implementation phase is foreseen to start shortly afterwards, with a launch in 2016.
Thousands of surplus aircraft are stored in the desert southwest. Most will become scrap, some will supply spare parts and a few will fly again. The number of B52 bombers is regulated by treaty with the Russians to 76. When one was severely damaged in a fire a mothballed airplane was brought back into service. These are ancient aircraft.
Spot is the latest four legged robot from Boston Dynamics (which Google bought a few years ago). Watching this type of robot can be unsettling as they are close to animal locomotion, but are not a perfect match - sort of like the old generation Cylons in the remake of Battlestar Galactica. There is an uncanny valley effect where something doesn't seem quite right.
hat tips to the half dozen people who sent the link!
I haven't seen one for years. This one isn't new, but has the feature of being online.
Computer-generated “random” numbers are more properly referred to as pseudorandom numbers, and pseudorandom sequences of such numbers. A variety of clever algorithms have been developed which generate sequences of numbers which pass every statistical test used to distinguish random sequences from those containing some pattern or internal order. A test program is available at this site which applies such tests to sequences of bytes and reports how random they appear to be, and if you run this program on data generated by a high-quality pseudorandom sequence generator, you'll find it generates data that are indistinguishable from a sequence of bytes chosen at random. Indistinguishable, but not genuinely random.
HotBits is an Internet resource that brings genuine random numbers, generated by a process fundamentally governed by the inherent uncertainty in the quantum mechanical laws of nature, directly to your computer in a variety of forms. HotBits are generated by timing successive pairs of radioactive decays detected by a Geiger-Müller tube interfaced to a computer. You order up your serving of HotBits by filling out a request form specifying how many random bytes you want and in which format you'd like them delivered. Your request is relayed to the HotBits server, which flashes the random bytes back to you over the Web. Since the HotBits generation hardware produces data at a modest rate (about 100 bytes per second), requests are filled from an “inventory” of pre-built HotBits. Once the random bytes are delivered to you, they are immediately discarded—the same data will never be sent to any other user and no records are kept of the data at this or any other site. (Of course, if you're using the random data for cryptography or other security-related applications, you can't be certain I'm not squirreling away a copy. But I'm not, really.)
DARPA's Airborne Launch Assist Space Access program is making progress. The idea is to launch a small payload from a fighter from an altitude above roughly 90% of the Earth's atmosphere and bring the cost down to about $1 million per launch with the ability to fly within 24 hours of notice.
For the handful of RPN calculator fans - a community project that goes well beyond the capabilities of the old HP 42S. The WP 34S does Riemann's Zeta functions and Legendre polynomials. I have more function with Wolfram alpha on my iPhone, but this is strangely attractive. There is also an iPhone version, but somehow the physical unit is desirable.