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ESA ACT

New rocket aims for cheaper nudges in space - MIT News Office - 0 views

web.mit.edu/...plasma-rocket-0224.html

pro

shared by ESA ACT on 24 Apr 09 - Cached
  • ESA ACT on 24 Apr 09
     
    I don't quite get it but I want to...
Luís F. Simões

Pioneer Anomaly Solved By 1970s Computer Graphics Technique - Technology Review - 4 views

www.technologyreview.com/...26589

pioneer anomaly PHY astrophysics

shared by Luís F. Simões on 31 Mar 11 - No Cached
Nicholas Lan liked it
  • Now Frederico Francisco at the Instituto de Plasmas e Fusao Nuclear in Lisbon Portugal, and a few pals, say they've worked out where the thermal calculations went wrong. These guys have redone the calculations using a computer model of not only how the heat is emitted but how it is reflected off the various parts of the spacecraft too. The reflections turn out to be crucial.
  • Ref: arxiv.org/abs/1103.5222: Modelling The Reflective Thermal Contribution To The Acceleration Of The Pioneer Spacecraft
  • santecarloni on 01 Apr 11
     
    This is really cool. I know one of the authors and he is a good guy... the only thing that leaves me unsatisfied is that if the whole issue is related to thermal effects one should have seen the Pioneer effect all the time and not only at about 10 AU... ...or is there some thermal process that kicked in only at this distance?
  • Luís F. Simões on 26 Jul 11
     
    Here's an update on this theory: NASA Releases New Pioneer Anomaly Analysis "The mysterious force acting on the Pioneer spacecraft seems to be falling exponentially. That's a strong clue that on-board heat is to blame, says NASA." Heat emission 'most likely cause' of pioneer anomaly "What's more interesting is that, contrary to the original analysis conducted all those years ago, the deceleration does seem to be decelerating at an exponential rate -- just as one might expect from the radioactive decay of plutonium-238, which powers the two spacecraft. Turyshev concludes, "The most likely cause of the Pioneer anomaly is the anisotropic emission of on-board heat.""
H H

Lockheed Claims Breakthrough on Fusion Energy - 3 views

www.scientificamerican.com/...-breakthrough-on-fusion-energy

PHY fusion energy

shared by H H on 15 Oct 14 - No Cached
  • H H on 15 Oct 14
     
    Lockheed Martin Corp said on Wednesday it had made a technological breakthrough in developing a power source based on nuclear fusion, and the first reactors, small enough to fit on the back of a truck, could be ready in a decade.
  • Thijs Versloot on 17 Oct 14
     
    Is positive news definitely, but when it comes to fusion energy being skeptic is the wisest course of action. On the back of a truck basically means that the energy density of the device is such that the surface energy of a (steady state) plasma is beyond currents materials limits. It is probably a pulsed (ignitor-type) device, which are prone to instabilities. That could therefore refer to their breakthrough claim, of which they hardly say anything though. Lets see
  • jcunha on 17 Oct 14
     
    Since there were already a lot of false alarms on the field, one should definitively be careful about it. However not a single detail about its structure or how it works in this new... Here http://www.fusenet.eu/node/400 you can find a bit more of information about it.
anonymous

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

www.wired.co.uk/...lidates-impossible-space-drive

PHY space nasa propulsion emdrive

shared by anonymous on 31 Jul 14 - No Cached
  • anonymous on 31 Jul 14
     
    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.")
  • ...3 more comments...
  • LeopoldS on 01 Aug 14
     
    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.
  • anonymous on 02 Aug 14
     
    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
  • Thijs Versloot on 04 Aug 14
     
    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?
  • annaheffernan on 04 Aug 14
     
    I have to join the skeptics on this one ...
  • Marcus Maertens on 09 Aug 14
annaheffernan

Filamentous laser beams point to new type of phase transition - applications in weather... - 2 views

physicsworld.com/...o-new-type-of-phase-transition

technology science PHY earthscience

shared by annaheffernan on 02 Mar 15 - No Cached
LeopoldS liked it
  • annaheffernan on 02 Mar 15
     
    Filaments of plasma created by a high-powered laser beam undergo a similar type of phase transition as liquid percolating through a porous material - that is the conclusion of physicists in Switzerland. The also describe the application of laser filamentation for directed lightening and encouraged rainfall - Isabelle should come back to take a closer look :p
  • LeopoldS on 11 Mar 15
     
    Christophe? Isabelle?
Thijs Versloot

Ultrafast collisional ion heating by electrostatic shocks - 0 views

www.nature.com/...ncomms9905.html

shared by Thijs Versloot on 23 Nov 15 - No Cached
jcunha liked it
  • Thijs Versloot on 23 Nov 15
     
    Collisionless electrostatic shocks (CES) are the dominant process in heating a plasma when using high power lasers. It turns out that ion-ion collisions actually only play a small role. The ability to create small regions of very high ion energy density on time scales shorter than that of hydrodynamic expansion will be of interest in attempts to understand the processes involved in inertial confinement fusion.
marliesarnhof

MIT and newly formed company launch novel approach to fusion power | MIT News - 1 views

news.mit.edu/...vel-approach-fusion-power-0309

PHY technology science

shared by marliesarnhof on 09 Mar 18 - No Cached
  • marliesarnhof on 09 Mar 18
     
    Scientists anticipate the output would be more than twice the power used to heat the plasma, achieving the ultimate technical milestone: positive net energy from fusion.
jaihobah

Demonstrating a new technology for space debris removal using a bi-directional plasma t... - 2 views

www.nature.com/...s41598-018-32697-4

space PHY

shared by jaihobah on 01 Oct 18 - No Cached
  • jaihobah on 01 Oct 18
     
    Some people answering the question 'What's cooler than blasting space debris with lasers...?'.
  • Marcus Maertens on 03 Oct 18
     
    If it fires in both directions, can we align it such that it deorbits two debris with one shot?
  • Dario Izzo on 05 Oct 18
     
    :) the idea of having this method for debris removal is actually an ACT one from Claudio Bombardelli (ACT RF in MAD https://en.wikipedia.org/wiki/Ion-beam_shepherd). This is just a technological device to implement it so that the system on board is simplified (i.e. instead of two engines, you get away with one and a weird nozzle) Marcus, you cannot align it to get rid of two debris as you need to keep the spacecraft close to the debris as this is a long duration acion. One of the two would drift away (can only follow one!)
LeopoldS

The case for in situ resource utilisation for oxygen production on Mars by non-equilibr... - 6 views

iopscience.iop.org/...aa8dcc

ISRU

shared by LeopoldS on 19 Oct 17 - No Cached
Marion Nachon liked it
  • LeopoldS on 04 Jan 18
     
    interesting idea to produce O2 differently on Mars
  • Marion Nachon on 15 Jan 18
     
    Also, let's see how MOXIE does onboard the Mars2020 rover! https://mars.nasa.gov/mars2020/mission/instruments/moxie/for-scientists/
marliesarnhof

Evidence of a plume on Europa from Galileo magnetic and plasma wave signatures | Nature... - 1 views

www.nature.com/...s41550-018-0450-z

space science

shared by marliesarnhof on 15 May 18 - No Cached
  • marliesarnhof on 15 May 18
     
    Old data reveal new evidence of europa spouting plumes into space.
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