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We're obviously not crypto-bros in the team, but this lengthy article is nonetheless very much worth a read to try to make sense of all this madness. Written by an expert in economics and finance, doesn't hold back any punches!

Some people answering the question 'What's cooler than blasting space debris with lasers...?'.

If it fires in both directions, can we align it such that it deorbits two debris with one shot?

:) 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!)

Nautral Light for Human Space Exploration

wow, that looks pretty real to me! I remember a presentation some time ago on difficulties with large scale LED lights for making directed light sources. I guess we can cross that off the list :)

Agata - have a look at this!

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... :)

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.

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 .

To right that appalling wrong, here we attempt to explain the apparently erratic seasonal changes in the world of G.R.R.M. A natural explanation for such phenomena is the unique behavior of a circumbinary planet. Thus, by speculating that the planet under scrutiny is orbiting a pair of stars, we utilize the power of numerical three-body dynamics to predict that, unfortunately, it is not possible to predict either the length, or the severity of any coming winter.

ooops ....

Where is the sticker saying "if found, please post this item unstamped to the following address"?

Yup, it's ours... Still, better take it out of the river than in the face. Such a big one especially.

We made it to Slashdot's frontpage !!! :)

Congratulations, gentlemen!

The French Space Agency (CNES) commissioned Damien Labrousse to recreate the Jupiter Mission Control Room in Lego for display at the Kourou spaceport. The impressive build features 6,000 bricks, 80 minifigs, a working video screen that shows the rocket launch sequence and a sound system, displaying launch countdown.

The square wheel!

Our mission is very simple. We are working towards launching a human being into space. 

Nicholas this is project I mentioned while G&T-ing in Madrid.

They search numerically for initial conditions resulting in periodic orbits. Reminds to me the methods we employed for the "search for invariant relative motion" and which brought us to discover the magic inclinations (47.9 degrees). I wonder what are the implications. In any case nice plots :)

Haven't read in detail, but it's not clear to me what it means exactly. If they were discovered numerically (I assume it means via numerical integration), how can they be sure the orbits are truly periodic?

nice - did not know about it. GTOC on steroids and with loads of cash. concerning this specific challenge and especially the last condition: doesn't this hint towards a flawed design? In addition to maximizing the total power output there are some constraints on the possible movements: Each SARJ and BGA is limited to a maximum angular velocity and to a maximum angular acceleration. Each SAW must produce at least some minimum average power over the orbit (which is different for each SAW). The sequence of positions must be cyclic, so it can be repeated on the next orbit. The maximum amount of BGA rotation is not limited, but exceeding a threshold will result in a score penalty. Some structural members of the SAW mast (called Longerons) have restrictions on how they can be shadowed.

The longerons will expand and contract with exposition to sun (I think whatever the material they are made of). Because you have 4 longerons in a mast, you just need to be carefull that the mast is well balanced, and that the 4 longerons support each other, basically, you need an even number of shadowed longerons, possibly 0 too. I would call this an operational constraint.

Apophis is back! You can watch its close approach live. Announcement: http://images.slooh.com/files/press_release/asteroid_apophis2013.pdf

interesting stuff ... I like this quote "When a man tells you about the time he planned to put a vegetable garden on Mars, you worry about his mental state. But if that same man has since launched multiple rockets that are actually capable of reaching Mars-sending them into orbit, Bond-style, from a tiny island in the Pacific-you need to find another diagnosis. That's the thing about extreme entrepreneurialism: There's a fine line between madness and genius, and you need a little bit of both to really change the world. All entrepreneurs have an aptitude for risk, but more important than that is their capacity for self-delusion. Indeed, psychological investigations have found that entrepreneurs aren't more risk-tolerant than non-entrepreneurs. They just have an extraordinary ability to believe in their own visions, so much so that they think what they're embarking on isn't really that risky. They're wrong, of course, but without the ability to be so wrong-to willfully ignore all those naysayers and all that evidence to the contrary-no one would possess the necessary audacity to start something radically new."

I know you like these... [Edit] And by the way, this website contains also more practical stuff, like this

of course, "they" being Polish Wikipedia contributors who geo-tag like mad...

Have you had a look on Japan? It looks like they just geo-tagged all their train stations.

Boh....

What's next? Lego satellites!

Connected to asteroid deflection? :)

Have you seen this?!

no! quite impressive indeed! thanks for sharing it here

On March 28, ATV-3, named Edoardo Amaldi, docked with the ISS. Astronauts on the station took this unbelievable picture of it as it approached

More pics here: http://www.flickr.com/photos/europeanspaceagency/ ATV docking is a bit further down the photostream.