1977年的8月和9月,承载着时人重大梦想的旅行者号飞船1号(Voyager 1)和2号(Voyager 2)相继出发,离开地球(这里只讲旅行者号,因为篇幅所限,先驱者10号和11号的事不提,要了解的朋友去这里:Space Today Online -- The Pioneer spacecraft still are outbound)。
This fabled technology converts the impulses of small nuclear detonations into thrust.
The small shaped-charge bombs each have a mass of 230 kg (including propellant) and a yield of a quarter kiloton (1 terajoule). The fissile material is curium 245, with a critical mass of 4 kg, surrounded by a beryllium reflector. The soft X-rays, UV and plasma from the external detonation vaporize and compress the propellant to a gram per liter, highly opaque to the bomb energies at the temperatures attained (67000 K).
引自[url=]Engine List - Atomic Rockets[/url]
在上世纪50年代的后期,弗里曼·戴森和泰德·泰勒等人就这个项目煞费苦心,但是没办法,1963年的《部分禁止核试验条约》(Partial Test Ban Treaty, PTBT)直接中止了这个项目,合约中明确说明了不能在外层空间包括大气层、外太空进行一切核试验有关的活动。
使用高速档的VASIMR,其排气速度可以达到惊人的294000m/s。2004年,NASA Johnson Space Center的Advanced Space Propulsion Laboratory就写了一篇小科普,大家有兴趣可以去看看:http://web.mit.edu/mars/Conference_Archives/MarsWeek04_April/Speaker_Documents/VASIMREngine-TimGlover.pdf
Instead of converting the Sun's energy to usable electricity like traditional solar-powered space vehicles, a fully functional LightSail will coast on the sun's rays, moving its sail to and fro to make sure the solar radiation is constantly propelling it in the direction it wants to go. In other words, it surfs through space without burning fuel.
引自Bill Nye's first LightSail probe to launch Wednesday
Solar sail spacecraft capture light momentum with large, lightweight mirrored surfaces—sails. As light reflects off a sail, most of its momentum is transferred, pushing on the sail. The resulting acceleration is small, but continuous. Unlike chemical rockets that provide short bursts of thrust, solar sails thrust continuously and can reach higher speeds over time.
图片来自Kugelblitz! Powering a Starship With a Black Hole
Kugelblitz! Powering a Starship With a Black Hole这篇文章花了一大段讲这种科幻技术,太长了。
我为大家摘一段维基上的介绍:
In theoretical physics, a kugelblitz (German: "ball lightning") is a concentration of light so intense that it forms an event horizon and becomes self-trapped: according to general relativity, if enough radiation is aimed into a region, the concentration of energy can warp spacetime enough for the region to become a black hole (although this would be a black hole whose original mass-energy had been in the form of radiant energy rather than matter). In simpler terms, a kugelblitz is a black hole formed from energy as opposed to mass.