Antimatter's allure for deep space propulsion is obvious. If matter is congealed energy, we need to find the best way to extract that energy, and our existing rockets are grossly inefficient. Even the best chemical rocket pulls only a billionth of the energy available in the atoms of its fuel, while a fission reaction, powerful as it seems, is tapping one part in a thousand of what is available. Fusion reactions like those in a hydrogen bomb use up something on the order of one percent of the total energy within matter. But antimatter can theoretically unlock all of it. Freeing Trapped Energy The numbers are startling. A kilogram of antimatter, annihilating with ordinary matter, can produce ten billion times the amount of energy released when a kilogram of TNT explodes. Heck, a single gram of antimatter, which is about 1/25th of an ounce, would get you as much energy as you could produce from the fuel tanks of two dozen Space Shuttles. This is the ultimate kick if we can figure out a...
Meteorites a Key to Habitability?
You wouldn't think life on a planet being bombarded by debris in the early days of its solar system would have much chance for survival. Indeed, the prospect of being pummeled for millions of years in the Late Heavy Bombardment has led to scenarios in which life started, was extinguished, and re-started on this planet, the idea being that the massive cratering we see on objects like the moon was also being enacted here. But maybe we can make a virtue of necessity and consider what all those incoming objects might have done long-term to improve the atmospheres of the planets they landed on. So goes the thinking in a new study that examines the composition of ancient meteorites to see what they would do when heated to temperatures like those caused by a fiery descent to Earth. Using a method called pyrolysis-FTIR, in which the meteorite fragments were quickly heated (at a remarkable 20,000 degrees Celsius per second), the team measured the carbon dioxide and water vapor released. It...
Millisecond Pulsars for Starship Navigation
If we can use GPS satellites to find out where we are on Earth, why not turn to the same principle for navigation in space? The idea has a certain currency -- I remember running into it in John Mauldin's mammoth (and hard to find) Prospects for Interstellar Travel (AIAA/Univelt, 1992) some years back. But it was only a note in Mauldin's 'astrogation' chapter, which also discussed 'marker' stars like Rigel (Beta Orionis) and Antares (Alpha Scorpii) and detailed the problems deep space navigators would face. The European Space Agency's Ariadna initiative studied pulsar navigation relying on millisecond pulsars, rotating neutron stars that spin faster than 40 revolutions per second. The pitch here is that pulsars that fit this description are old and thus quite regular in their rotation. Their pulses, in other words, can be used as exquisitely accurate timing mechanisms. You can have a look at ESA's "Feasibility study for a spacecraft navigation system relying on pulsar timing...