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ESA ACT

PG&E makes deal for space solar power - Space- msnbc.com - 0 views

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    unexpected indeed .... have to check to find out more ... (LS)
ESA ACT

Smartlighting ERC | Free space communications | Photonics | LED | Wireless | CISE | BU - 0 views

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    application for space? maybe ISS? -LS
evo ata

Future Human Evolution - 1 views

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    Scientific and speculative articles about the future of human evolution regarding to artificial intelligence, genetic engineering, transhumanism, nanotechnology, space colonization, time travel, life extension and human enhancement
ESA ACT

SPACE.com -- Delays and Cost Overruns Epidemic at NASA, Former Official Charges - 0 views

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    we could say to them " welcome to the club" ...
nikolas smyrlakis

LaserMotive » Blog - 2 views

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    the team that won the 900.000$ second prize for the space elevator competition (Noone won the 2mil.$ first prize..) for "laser power beaming" a platform at 1km altitude
Juxi Leitner

GetRobo Blog: Toyota's humanoid to explore moon by 2020? - 1 views

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    "slides which were presented by an executive at Toyota during some kind of task force meeting that discusses Japan's direction/strategy in space exploration"
LeopoldS

Questions Surround European Cooperative Military Space Programs | SpaceNews.com - 3 views

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    start of the end of the ESA space defence activities .. ?
Luís F. Simões

Following SpaceX down the rabbit hole -- The Space Review - 4 views

  • He then went on to remind the press that his company’s goal is to continue to lower the cost of access to space because high launch costs were “the fundamental factor preventing humanity from becoming a spacefaring civilization.”
  • First, two Falcon Heavy launches could field a return to the Moon
  • Second, a single Falcon Heavy could launch a Mars sample return mission.
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  • Also possible with a single launch: a first ever human mission to an asteroid.
  • what effect Falcon Heavy might have on the costs of supporting the International Space Station. The ability to launch twice the supply capacity provided by the shuttle at something on the order of 20 percent of the cost changes the calculus entirely. So much so in fact, it opens the door for contemplating an entirely different future for ISS in which it never follows Mir into the Pacific.
  • Following conclusions offered by the Augustine Committee, the Obama Administration cancelled Project Constellation as unaffordable under existing budget limits, and supported instead the ambling, but cost-contained “flexible path.” If the Falcon Heavy is available, however, the rationale for selecting the flexible path—because it’s the only thing we can afford—simply doesn’t exist.
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    an analysis of implications of the Falcon Heavy announcement
LeopoldS

2aPEACE letters formed by concert participants ... visible via EO satellites - 1 views

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    in french - though language not important ... letters visible from space during concert ... 
santecarloni

[1101.6015] Radio beam vorticity and orbital angular momentum - 1 views

  • It has been known for a century that electromagnetic fields can transport not only energy and linear momentum but also angular momentum. However, it was not until twenty years ago, with the discovery in laser optics of experimental techniques for the generation, detection and manipulation of photons in well-defined, pure orbital angular momentum (OAM) states, that twisted light and its pertinent optical vorticity and phase singularities began to come into widespread use in science and technology. We have now shown experimentally how OAM and vorticity can be readily imparted onto radio beams. Our results extend those of earlier experiments on angular momentum and vorticity in radio in that we used a single antenna and reflector to directly generate twisted radio beams and verified that their topological properties agree with theoretical predictions. This opens the possibility to work with photon OAM at frequencies low enough to allow the use of antennas and digital signal processing, thus enabling software controlled experimentation also with first-order quantities, and not only second (and higher) order quantities as in optics-type experiments. Since the OAM state space is infinite, our findings provide new tools for achieving high efficiency in radio communications and radar technology.
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    It has been known for a century that electromagnetic fields can transport not only energy and linear momentum but also angular momentum. However, it was not until twenty years ago, with the discovery in laser optics of experimental techniques for the generation, detection and manipulation of photons in well-defined, pure orbital angular momentum (OAM) states, that twisted light and its pertinent optical vorticity and phase singularities began to come into widespread use in science and technology. We have now shown experimentally how OAM and vorticity can be readily imparted onto radio beams. Our results extend those of earlier experiments on angular momentum and vorticity in radio in that we used a single antenna and reflector to directly generate twisted radio beams and verified that their topological properties agree with theoretical predictions. This opens the possibility to work with photon OAM at frequencies low enough to allow the use of antennas and digital signal processing, thus enabling software controlled experimentation also with first-order quantities, and not only second (and higher) order quantities as in optics-type experiments. Since the OAM state space is infinite, our findings provide new tools for achieving high efficiency in radio communications and radar technology.
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    and how can we use this?
LeopoldS

KickSat -- Your personal spacecraft in space! by Zachary Manchester - Kickstarter - 0 views

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    as predicted in 2008 ...
jmlloren

Scientists discover how to turn light into matter after 80-year quest - 5 views

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    Theoretized 80 years ago was Breit-Wheeler pair production in which two photons result in an electron-positron pair (via a virtual electron). It is a relatively simple Feynmann diagram, but the problem is/was how to produce in practice a high energy photon-photon collider... The collider experiment that the scientists have proposed involves two key steps. First, the scientists would use an extremely powerful high-intensity laser to speed up electrons to just below the speed of light. They would then fire these electrons into a slab of gold to create a beam of photons a billion times more energetic than visible light. The next stage of the experiment involves a tiny gold can called a hohlraum (German for 'empty room'). Scientists would fire a high-energy laser at the inner surface of this gold can, to create a thermal radiation field, generating light similar to the light emitted by stars. They would then direct the photon beam from the first stage of the experiment through the centre of the can, causing the photons from the two sources to collide and form electrons and positrons. It would then be possible to detect the formation of the electrons and positrons when they exited the can. Now this is a good experiment... :)
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    The solution of thrusting in space.
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    Thrusting in space is solved already. Maybe you wanted to say something different?
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    Thrusting until your fuel runs out is solved, in this way one can produce mass from, among others, solar/star energy directly. What I like about this experiment is that we have the technology already to do it, many parts have been designed for inertial confinement fusion.
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    I am quite certain that it would be more efficient to use the photons directly for thrust instead of converting them into matter. Also, I am a bit puzzled at the asymmetric layout for photon creation. Typically, colliders use two beam of particle with equal but opposite momentum. Because the total momentum for two colliding particles is zero the reaction products are produced more efficiently as a minimum of collision energy is waisted on accelerating the products. I guess in this case the thermal radiation in the cavity is chosen instead of an opposing gamma ray beam to increase the photon density and increase the number of collisions (even if the efficiency decreases because of the asymmetry). However, a danger from using a high temperature cavity might be that a lot of thermionic emission creates lots of free electrons with the cavity. This could reduce the positron yield through recombination and would allow the high energetic photons to loose energy through Compton scattering instead of the Breit-Wheeler pair production.
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    Well, the main benefit from e-p pair creation might be that one can accelerate these subsequently to higher energies again. I think the photon-photon cross-section is extremely low, such that direct beam-beam interactions are basically not happening (below 1/20.. so basically 0 according to quantum probability :P), in this way, the central line of the hohlraum actually has a very high photon density and if timed correctly maximizes the reaction yield such that it could be measured.
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    I agree about the reason for the hohlraum - but I also keep my reservations about the drawbacks. About the pair production as fuel: I pretty sure that your energy would be used smarter in using photon (not necessarily high energy photons) for thrust directly instead of putting tons of energy in creating a rest-mass and then accelerating that. If you look at E² = (p c)²+(m0 c)² then putting energy into the mass term will always reduce your maximum value of p.
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    True, but isnt it E2=(pc)^2 + (m0c^2)^2 such that for photons E\propto{pc} and for mass E\propto{mc^2}. I agree it will take a lot of energy, but this assumes that that wont be the problem at least. The question therefore is whether the mass flow of the photon rocket (fuel consumed to create photons, eg fission/fusion) is higher/lower than the mass flow for e-p creation. You are probably right that the low e-p cross-section will favour direct use of photons to create low thrust for long periods of time, but with significant power available the ISP might be higher for e-p pair creation.
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    In essence the equation tells you that for photons with zero rest mass m0 all the energy will be converted to momentum of the particles. If you want to accelerate e-p then you first spend part of the energy on creating them (~511 keV each) and you can only use the remaining energy to accelerate them. In this case the equation gives you a lower particle momentum which leads to lower thrust (even when assuming 100% acceleration efficiency). ISP is a tricky concept in this case because there are different definitions which clash in the relativistic context (due to the concept of mass flow). R. Tinder gets to a I_SP = c (speed of light) for a photon rocket (using the relativistic mass of the photons) which is the maximum possible relativistic I_SP: http://goo.gl/Zz5gyC .
jcunha

Mystery of where Earth's water came from deepens: Comet water is different - 2 views

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    "Over the past few months, the European Space Agency's Rosetta space probe closely examined the type of comet that some scientists theorized could have brought water to our planet 4 billion years ago. It found water, but the wrong kind."
anonymous

Nasa validates 'impossible' space drive (Wired UK) - 3 views

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    NASA validates the EmDrive (http://emdrive.com/) technology for converting electrical energy into thrust. (from the website: "Thrust is produced by the amplification of the radiation pressure of an electromagnetic wave propagated through a resonant waveguide assembly.")
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    I would be very very skeptic on this results and am actually ready to take bets that they are victims of something else than "new physics" ... some measurement error e.g.
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    Assuming that this system is feasible, and taking the results of Chinese team (Thrust of 720 mN http://www.wired.co.uk/news/archive/2013-02/06/emdrive-and-cold-fusion), I wonder whether this would allow for some actual trajectory maneuvers (and to which degree). If so, can we simulate some possible trajectories, e.g. compare the current solutions to this one ? For example, Shawyer (original author) claims that this system would be capable of stabilizing ISS without need for refueling. Other article on the same topic: http://www.theverge.com/2014/8/1/5959637/nasa-cannae-drive-tests-have-promising-results
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    To be exact, the chinese reported 720mN and the americans found ~50microN. The first one I simply do not believe and the second one seems more credible, yet it has to be said that measuring such low thrust levels on a thrust-stand is very difficult and prone to measurement errors. @Krzys, the thrust level of 720mN is within the same range of other electric propulsion systems which are considered - and even used in some cases - for station keeping, also for the ISS actually (for which there are also ideas to use a high power system delivering several Newtons of thrust). Then on the idea, I do not rule out that an interaction between the EM waves and 'vacuum' could be possible, however if this would be true then this surely would be detectable in any particle accelerator as it would produce background events/noise. The energy densities involved and the conversion to thrust via some form of interaction with the vacuum surely could not provide thrusts in the range reported by the chinese, nor the americans. The laws of momentum conservation would still need to apply. Finally, 'quantum vacuum virtual plasma'.. really?
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    I have to join the skeptics on this one ...
Isabelle Dicaire

Testing of a femtosecond pulse laser in outer space : Scientific Reports : Nature Publi... - 2 views

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    Good news for fundamental physics and Earth system science, femtosecond lasers are now about to achieve space qualification thanks to fibre optics!  Applications include high resolution spectroscopy, absolute laser ranging, mapping of the geo-potential and testing of the theory of general relativity to name a few!
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    nice paper by the Koreans, did not know that they had already such a laser in orbit for a year. How much would this type be upscalable for our needs? in case we have not, we should reference it
Thijs Versloot

Spotting East African Mammals in Open Savannah from Space - 1 views

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    A hybrid image classification method was employed for this specific purpose by incorporating the advantages of both pixel-based and object-based image classification approaches. This was performed in two steps: firstly, a pixel-based image classification method, i.e., artificial neural network was applied to classify potential targets with similar spectral reflectance at pixel level; and then an object-based image classification method was used to further differentiate animal targets from the surrounding landscapes through the applications of expert knowledge. As a result, the large animals in two pilot study areas were successfully detected with an average count error of 8.2%, omission error of 6.6% and commission error of 13.7%. The results of the study show for the first time that it is feasible to perform automated detection and counting of large wild animals in open savannahs from space
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    And Paul, it includes neural networks!
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    I kept telling you guys but you just laughed and laughed :))
annaheffernan

Mining the moon - 1 views

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    Mining the moon - now we know that the Moon's poles hold millions of tonnes of water ice, firms in the US as well as the Indian and Chinese space agencies are planning to mine this resource and sell it to space missions as fuel.
LeopoldS

These Are the Sad Remains of the Soviet Space Shuttle Program - 6 views

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    sad series of images ...
LeopoldS

Luxembourg to support space mining - BBC News - 1 views

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    interesting move! Luxembourg - the silicon valley for space entrepreneurs in Europe ...?
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