Group items tagged

ACT RFs should be able to go on mission in one of those once a year

NASA aims to "create a healthy private-sector competition for transport to the space station". Through this the development of space tourism is enforced and an increase in the number of rocket launches should be expected. 

Interesting article about your Cryosat. Don't miss the Dniepr launch videos and the story about Kazakh surgeon fixing the satellite :)

All the satellite-related systems (except for the rocket to launch it) are DIY programs -- designed so that regular people may also have the chance of developing and eventually launching their own.

I was saying that mainly because of some flaws - the piggy-pack installation, no dedicated stage, the limited control, ... It is so far very funny, but once he can fill all the gaps, it should be an excellent initiative - although careful about the debris if anyone has its own ;p

his quote: "when art becomes practical, we call it technology; when technology becomes useless, we call it art" ... this is probably the later one ....

I don't quite get it but I want to...

also interesting (for the Earth Science girls): Nilton Renno of the University of Michigan, who studies how rocket plumes from Mars landers affect the Martian surface.

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 .

Rocket science!

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."

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.

"Hbar Technologies plans a Kickstarter effort to raise US $200,000 for the next phase design of an antimatter-propelled spaceship. The two scientists behind this design effort are a veteran Fermilab particle accelerator scientist and a former Los Alamos National Laboratory physicist and founding director of the U.S. Center for Space Nuclear Research. They originally developed it for NASA at the turn of the millennium."

Two aerospace companies are teaming up to launch giant space habitats to orbit, with the first such liftoff targeted for 2020. Bigelow Aerospace will loft its giant, expandable B330 modules - each of which will provide one-third as much usable volume as the entire International Space Station (ISS) - aboard United Launch Alliance (ULA) Atlas V rockets, representatives from both companies announced today (April 11).

Time to get out the Fission Fragment Rocket Engine!

At 8:33 a.m., (Japan Standard Time) January 15, 2017, SS-520 No. 4, JAXA's sounding rocket launched from the Uchinoura Space Center. Through SS-520 No. 4 launch, JAXA sought for research and development of launch vehicles and satellites and the launch demonstration of TRICOM-1, its onboard nanosat that weighs about 3 kilograms. The launch was part of Japanese government's program for development of launch vehicles and satellites in public-private partnerships. Long story short: Space-X has the better fireworks