|
Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. There are many different methods. Each method has drawbacks and advantages, and spacecraft propulsion is an active area of research. However, most spacecraft today are propelled by forcing a gas from the back/rear of the vehicle at very high speed through a supersonic de Laval nozzle. This sort of engine is called a rocket engine. All current spacecraft use chemical rockets (bipropellant or solid-fuel) for launch, though some (such as the Pegasus rocket and SpaceShipOne) have used air-breathing engines on their first stage. Most satellites have simple reliable chemical thrusters (often monopropellant rockets) or resistojet rockets for orbital station-keeping and some use momentum wheels for attitude control. Soviet bloc satellites have used electric propulsion for decades, and newer Western geo-orbiting spacecraft are starting to use them for north-south stationkeeping. Interplanetary vehicles mostly use chemical rockets as well, although a few have experimentally used ion thrusters (a form of electric propulsion) to great success. From Wikipedia under the
GNU Free Documentation License  aoas.org 159px x 200px | 8.80kB [source page] Dawn will be the first spacecraft to establish orbits around two separate target bodies during its mission thanks to ion propulsion validated by Deep Space 1 Ion  images.brighthub.com 150px x 150px | 38.00kB [source page] How Does it Work to Power Spacecraft But this is not the case Though these charged particles do have quite a bit of energy and are readily available a form of propulsion based solely on the solar wind and is technically more  aerospaceguide.net 350px x 500px | 24.40kB [source page] as its main propulsion system SMART stands for Small Missions for Advanced Research in Technology SMART 1 is the first of ESA s European Space Agency Small Missions for Advanced Research in Technology and has used many innovative From Yahoo Image Search: "spacecraft propulsion"  news.google.com The Hindu According to space engineering expert Yury Zaitsev, the Soviet Union launched a total of 32 spacecraft with small-capacity nuclear propulsion units in the ... Russia earmarks $17 mln to research nuclear-propelled spacecraft RIA Novosti Russia to develop nuclear-powered spacecraft RT Russia allocates $17 mn for N-powered spaceship Zee News Softpedia all 10 news articles » news.google.com PR Newswire (press release) In addition, he manages the overall policy definition, strategic planning, direction and administration of the Rocket Propulsion Test Program. ... and more » news.google.com Spaceflight Now China wrapped up 2009 with the launch of two dual use military reconnaissance/civil remote sensing spacecraft , one with an optical sensor and the second ... From Google News Search: "spacecraft propulsion" Why doesn't NASA build a more robust space-shuttle with new technologies in manufacturing and materials? Q. New technologies: materials, manufacturing, propulsion, testing, information flow among others. Improved overall aircraft and spacecraft design. Improved parts. Improved aerodynamics. There must be many new developments regarding the previous topics in science and engineering. Isn't it feasible to build a new Space Shuttle which is safer, more robust, more capable than the actual ones with so much new technology (named above) available today? It would be like comparing 1980 vs 2007's technology. Asked by johnflares - Wed May 16 00:38:47 2007 - - 15 Answers - 0 Comments A. A few years ago, NASA was indeed working on a replacement for the Space Shuttle. It was called the X-33 Venture Star, but it got cancelled in favor of the cheaper, simpler CEV concept (which has now evolved into the Orion and Ares programmes). I guess the reliability issues with a complex, winged reusable space vehicle (particularly in light of the two shuttle disasters) turned NASA off from the concept. It was a shame.. Lockheed actually had gotten a working prototype of the revolutionary Aerospike rocket engine for the X-33 up and running, and word has it that it had performed well on the static test stands. I would love to have seen a spaceship with one of those fly. Answered by thddspc - Wed May 16 01:36:19 2007 science help pleaseeee? ! (:? Q. i have no idea to do these and we have over 30 of them can do. can anyone pleaseee help me ? <3 1. a 400 kg bear grasping a vertical tree slides down at a constant velocity. what is the friction force that acts on the bear? 2. when two horizontal forces are exerted on a cart, a 600 N forward and a 400 N backward, the cart undergoes acceleration. what additional force is needed to produce non-accelerated motion? 3. you push with a 20 N horizontal force on a 2 kg mass resting on a horizontal surface against a horizontal friction forve of 12 N. what is the acceleration? 4. you push with a 40 N horizontal force on a 4 kg mass resting on a horizontal surface against a horizontal friction force of 24 N. what is the acceleration? 5. if a mass of… [cont.] Asked by xothegoodlife - Thu Dec 10 15:40:55 2009 - - 1 Answers - 0 Comments A. All the answers require the use of the equation F=ma. 1. Without friction, the bear would accelerate due to gravity, g. There is no acceleration, so the friction force F = -400g. [Have you been given a value for g?] 2. For non-accelerated motion, the forces must equal zero when added together. You need an extra 200N backwards. 3. 20-12 = 2a; a=4m/s . 4. 40-24 = 4a; a=4m/s . 5. a=F/m; a=1m/s . 6. a=25/100; a=0.25m/s . Get the idea? Q12 onwards involve vectors (directional forces). Calculate the resultant force by using Pythagoras' theorem. 12. 3 +4 = 5 , resultant speed is 5m/s. 13. 3 +4 = 5 , resultant force is 5N. a=F/m=5/5=1. Get the idea? Answered by warden - Thu Dec 10 16:01:28 2009 A serious question about the world's UFO sightings?
Q. OK, I admit that I am a bit of sceptic. But I will listen to everyone's arguments providing they are sensible. My question is this- any alien life that visits earth is obviously far in advance of us technologically. Their spacecraft must be almost beyond imagination in their methods of propulsion etc etc. So why, if a spacecraft was to come to earth and enter our atmosphere- perhaps to observe us humans- would it allow itself to be captured on camera? For that matter, why would it hover in plain sight, be be spotted by so many eye witnesses? If aliens had bothered to come all this way to observe us, of for that matter, do almost anything else, would they not either make contact or remain entirely invisible? They must have the… [cont.] Asked by Rover - Wed May 14 06:58:18 2008 - - 12 Answers - 0 Comments A. Your question is improperly framed. You posit that, if aliens exist, they must have technology beyond ours. I will grant you that (without for one second granting that they exist at all, mind you) But the fact that they possess technology beyond ours does NOT mean that they have the ability to 'cloak' their craft. That works in Star Trek, that does not mean it is a possible technology. Or for that matter, nor does it mean it is a technology aliens would necessarily have developed. Technological advances are not always linear. The ancient Mayans had a lot of technological advances, but never developed the wheel, for instance. It could be that an advanced race has developed space travel, yet has just never hit upon cloaking devices.… [cont.] Answered by Actions have consequences - Wed May 14 12:03:34 2008 From Yahoo Answer Search: "spacecraft propulsion" |
