Robotengineer Posted April 4, 2015 Share Posted April 4, 2015 ~2500m² of solar panels.So it is in daylight when it goes over? Quote Link to comment Share on other sites More sharing options...
StrandedonEarth Posted April 4, 2015 Share Posted April 4, 2015 So it is in daylight when it goes over?Yes, that's why you won't see the ISS in the middle of the night. You might be in the dark, but the ISS is not in Earth's shadow yet. I've seen it fade out in the middle of a pass as it moves into darkness Quote Link to comment Share on other sites More sharing options...
K^2 Posted April 4, 2015 Share Posted April 4, 2015 Yup. Just like most satellites, ISS is visible when it's just about to pass or has just passed the terminator. When it's dark on the surface where you are looking at it, but light at the altitude where the satellite is passing.The only real exception I'm aware of is satellites that do orbit correction burns. You can see their flares when they are in total shadow. But these are pretty rare. Quote Link to comment Share on other sites More sharing options...
shynung Posted April 4, 2015 Share Posted April 4, 2015 Assuming an aircraft got its entire flight control surfaces inoperable and stuck in the neutral position (where the aircraft does not veer into any direction, but simply flies straight and level), but retaining control over engine thrust, is it possible to control and safely land and aircraft by shifting its center-of-mass around?(Say, by pumping fuel around tanks in various places around the plane.) Quote Link to comment Share on other sites More sharing options...
Camacha Posted April 4, 2015 Share Posted April 4, 2015 Assuming an aircraft got its entire flight control surfaces inoperable and stuck in the neutral position (where the aircraft does not veer into any direction, but simply flies straight and level), but retaining control over engine thrust, is it possible to control and safely land and aircraft by shifting its center-of-mass around?(Say, by pumping fuel around tanks in various places around the plane.)Engine thrust alone could be enough. After accidents where only control over engine thrust remained, technology was developed that can translate stick movement to engine thrust. Due to the extremely low number of incidents where this might help, it has never been implemented (though they might now be adding it).See this article for more information Quote Link to comment Share on other sites More sharing options...
K^2 Posted April 5, 2015 Share Posted April 5, 2015 Yeah, if you have multi-engine, all you need is engine controls. If you have a single-engine aircraft, you can get some roll authority by shifting the weight. You'd be at a mercy of a lot of factors, not least of which is wind, but you can at least give landing a solid try. If you don't get thrown by a gust of wind at the worst possible moment, you should be able to perform a soft landing. Quote Link to comment Share on other sites More sharing options...
WestAir Posted April 6, 2015 Share Posted April 6, 2015 There is a game called IL2 Pacific Fighters. The most fun you'll ever have is when anti air destroys your flight controls and you try and ferry the plane back to base using only differential thrust.The landings leave much to be desired. (Like usable gear or flame-free cabins) Quote Link to comment Share on other sites More sharing options...
shynung Posted May 2, 2015 Share Posted May 2, 2015 Is it possible to momentarily hide a spacecraft in space by storing said spacecraft's heat emissions into an internal heat sink, to be vented/radiated off at a safer condition? Quote Link to comment Share on other sites More sharing options...
RainDreamer Posted May 2, 2015 Share Posted May 2, 2015 Is it possible to momentarily hide a spacecraft in space by storing said spacecraft's heat emissions into an internal heat sink, to be vented/radiated off at a safer condition?I would say that will be possible to hide your craft from heat detectors. Pretty sure there were some ideas about storing the heat inside a detachable heatsink inside a vacuum container and launch it real fast away from the ship with cold gas, effectively masking your current position and create a decoy at the same time as the heat eventually radiate out from that container a distance away from you. Although you would need some ways to hide your space craft from other means of detection too. Quote Link to comment Share on other sites More sharing options...
Newt Posted May 2, 2015 Share Posted May 2, 2015 There might conceivably also be a way to absorb and store all of the energy from radar/ambient light that might hit a spacecraft as well, but it would likely be very difficult and costly to do for any length of time. Quote Link to comment Share on other sites More sharing options...
AngelLestat Posted May 2, 2015 Share Posted May 2, 2015 (edited) Heat management takes time and energy, less time --> much more energy --> which generates more heat.Heat is the form of energy more difficult to handle.stealth planes dont hide, they just bounce waves at angles difficult to intercept, in the heat case you can have a low emissivity ship surface with a radiation device to release your heat in a collimated way (hard but doable).But sticking to your example, I would pump liquid hellium(best) or hydrogen over the skin surface using cavities, that it would cold your ship by a while, then you would need to use a lot of energy to cold that hydrogen again. Edited May 2, 2015 by AngelLestat Quote Link to comment Share on other sites More sharing options...
peadar1987 Posted May 3, 2015 Share Posted May 3, 2015 Could you have a radiator that could be pointed perpendicular to the ecliptic, , in some sort of recess on the spacecraft. It would be less efficient (quite a lot less efficient), but also very hard to see if you weren't in an extremely inclined orbit Quote Link to comment Share on other sites More sharing options...
bs1110101 Posted May 3, 2015 Share Posted May 3, 2015 How big of a satellite would you need to properly test an EM Drive? Would putting one on a cubesat be possible? Quote Link to comment Share on other sites More sharing options...
andrewas Posted May 3, 2015 Share Posted May 3, 2015 Could you have a radiator that could be pointed perpendicular to the ecliptic, , in some sort of recess on the spacecraft. It would be less efficient (quite a lot less efficient), but also very hard to see if you weren't in an extremely inclined orbitYes, but you lose efficiency rapidly as you reduce the angle you radiate to. Also, in any scenario where you really want to hide, the enemy has probably taken steps to make it difficult, including placing sensor platforms in the outer solar system and off the ecliptic. Also, you can't use any but the lowest ISP engines without giving your position, velocity and mass away to any IR sensor platform in the system Quote Link to comment Share on other sites More sharing options...
AngelLestat Posted May 3, 2015 Share Posted May 3, 2015 the enemy has probably taken steps to make it difficult, including placing sensor platforms in the outer solar system and off the ecliptic. Also, you can't use any but the lowest ISP engines without giving your position, velocity and mass away to any IR sensor platform in the systemWhat?? heh.. that is a fail in many ways.. first.. if your sensor is so far away.. then it will be almost impossible to detect something so small as a ship. In case you can find it with magic, then it will take a long time to the heat reach the sensor, and it will take the same amount of time to alert earth. And all this depend in how collimated is the heat source.. if is well collimated there is almost not chance that your sensor is in the path, also you can radiate heat normal to the solar system plane or towards the sun.But well, spacewars is something that never would happen. Is complety pointless. At that level of technology you dont need to sent ships to eliminate life or targets. You can shoot micro capsules with nanovirus. Impossible to detect. Quote Link to comment Share on other sites More sharing options...
magnemoe Posted May 4, 2015 Share Posted May 4, 2015 How big of a satellite would you need to properly test an EM Drive? Would putting one on a cubesat be possible?Main problem with cubesats is power, however power is not the main problem, the main problem is that they are fiddling with the drive trying to get an version who works best. You can not do that then its in an satellite. Quote Link to comment Share on other sites More sharing options...
bs1110101 Posted May 4, 2015 Share Posted May 4, 2015 Main problem with cubesats is powerHow much power would be needed to get enough thrust from an EM Drive for it to be useful? Could one be scaled down to the point it could run off tiny cubesat panels? All the arguing about if these things work made me think they should just put one on a cubesat to test it, but if power is a problem i can see why they haven't. Quote Link to comment Share on other sites More sharing options...
Yru0 Posted May 6, 2015 Share Posted May 6, 2015 So the UAE anounced details about their misison to Mars on Wednesday. Definitely ambitious for a country still starting out in Space imho, and I am currently dealing with some jealousy issues (Come on Australia! We've got the 12th largest economy for pity's sake!). But, I can't quite grasp what they mean by a 'holistic' and 'global' view of the Martian climate? They say that it's never been done before, but surely that is the kind of thing NASA or ESA would love to sink their teeth into? Anybody here able to explain things in layman's terms, or perhaps more well-connected than I?I'm also curious what launcher they may end up using. The mission is scheduled for 2020, but as far as I'm aware the UAE has no domestic launch system so will have to look overseas. Any thoughts? Quote Link to comment Share on other sites More sharing options...
Mazon Del Posted May 6, 2015 Share Posted May 6, 2015 They could be banking on being able to snag a Falcon Heavy, should be ready in time I believe. Quote Link to comment Share on other sites More sharing options...
Kryten Posted May 6, 2015 Share Posted May 6, 2015 A first mission would be unlikely to be big enough to require an LV that big; I'd expect something on a Falcon 9, or something else in that general class. Quote Link to comment Share on other sites More sharing options...
RainDreamer Posted May 8, 2015 Share Posted May 8, 2015 What happens when massive objects enter a gas giant? Say, like a smaller dwarf planet got thrown into it? Just wondering what would happen to both. Quote Link to comment Share on other sites More sharing options...
peadar1987 Posted May 10, 2015 Share Posted May 10, 2015 What happens when massive objects enter a gas giant? Say, like a smaller dwarf planet got thrown into it? Just wondering what would happen to both.Om nom nom nom nom Quote Link to comment Share on other sites More sharing options...
Hcube Posted May 13, 2015 Share Posted May 13, 2015 Random question :I heard that the Falcon 9's tanks/structure are so lightweight, thin, and fragile that the rocket cannot stand on the pad by itself (it would collapse) without the umbilical tower unless the tanks are pressurized enough to keep them firm and steady.Is that true ? Where can i find a source ?If so, How does the rocket hold itself together midflight, when the tanks are mostly empty, and thus mostly non-pressurized ?Thanks ! Quote Link to comment Share on other sites More sharing options...
peadar1987 Posted May 13, 2015 Share Posted May 13, 2015 Random question :I heard that the Falcon 9's tanks/structure are so lightweight, thin, and fragile that the rocket cannot stand on the pad by itself (it would collapse) without the umbilical tower unless the tanks are pressurized enough to keep them firm and steady.Is that true ? Where can i find a source ?If so, How does the rocket hold itself together midflight, when the tanks are mostly empty, and thus mostly non-pressurized ?Thanks !Don't they backfill the tanks with helium, so they are always pressurised to some degree? Quote Link to comment Share on other sites More sharing options...
Kryten Posted May 13, 2015 Share Posted May 13, 2015 That clearly can't be true, or their return plans would make no sense; you can't land a rocket that can't even bear it's own weight. Quote Link to comment Share on other sites More sharing options...
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