Asteroids Millennium Free Download [Password]
Arnaud Richardson
Rocketing into the new millennium in the eight years since season three, Happy Valley has rapidly expanded its footprint on Mars by turning former foes into partners. Now 2003, the focus of the space program has turned to the capture and mining of extremely valuable, mineral-rich asteroids that could change the future of both Earth and Mars. But simmering tensions between the residents of the now-sprawling international base threaten to undo everything they are working towards.
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I observed Ceres on December 30th. I use Stellarium to get a general idea of where in the sky an asteroid is located and when it will be visible. I've found, however, that Stellarium's positions for asteroids are often off by many tens of arcminutes, even for asteroids whose orbital elements I have just updated.
A new study by University of Colorado and NASA scientists and accepted for publication in The Astronomical Journal, extended forecasts for the biggest known near-Earth asteroids by an order of magnitude and found none threaten Earth in the next thousand years.
In 1998, NASA asked scientists to find 90 percent of all near-Earth asteroids bigger than a kilometer. The 10-kilometer-wide asteroid that killed off the dinosaurs 66 million years ago belonged to this club. But even smaller strikes would be catastrophic.
Scientists believe such impacts happen every few million years, but until recent decades, there was simply no way to predict future strikes. No one had a list of likely candidates. NASA has since discovered nearly a thousand asteroids over a kilometer wide, or around 95 percent of the total in existence.
By making a series of observations, it is possible to study the rotation of some asteroids. Most have simple rotations around a fixed axis, with periods typically between one hour and one day. For example, here is a movie (83 kB MPEG) made by the Hubble Space Telescope of the asteroid Vesta in rotation (Ref). However, the asteroid 4179 Toutatis (which crosses Earth's orbit) has been found through radio telescope observations to have an irregular shape and a complex tumbling rotation---both thought to arise from a history of violent collisions. Here is a short animation (47 kB MPEG) of the spin of Toutatis; here is a longer animation (288 kB MPEG).
What's more awesome than asteroids? Asteroids you can put stuff in! Asteroid Recycling Technologies (ART) allows you to remove asteroid mass and attach multiple reconfigurable storage tanks to the asteroid's surface. ART is a collaboration between myself (plugin code, configs, and Unity), and WaRi (modeling and textures).
If you have been tracking the comings and goings of asteroids and comets regularly, then here is some news that may be of particular interest. The chances of an asteroid larger than a kilometre colliding with Earth within the next 1,000 years are low. However, there remains a potential risk from smaller asteroids, according to a recent study.
Researchers from the University of Colorado, Boulder, and NASA have conducted a study of nearly 1,000 near-Earth objects (NEOs) larger than one kilometre. Unlike previous analyses that focused on a century's worth of data, this study looked ahead an entire millennium.
It should be noted that the study did not evaluate smaller asteroids capable of causing city-level destruction, specifically those larger than 140 metres. Fuentes-Munoz explained that NASA's catalogue of such NEOs is currently about 40% complete, leaving uncertainties about their numbers. However, there is hope that new sky surveys will enhance the extensiveness rate.
The leading theory about how our neighbourhood came to be is this: the Sun coalesced from a compressed grouping of gas that eventually began fusing atoms and creating a protostar. Meanwhile, the dust and debris nearby the Sun began to coalesce. Small grains became small rocks, which crashed into each other to form bigger ones. The survivors of this chaotic period are the planets and the moons that we see today as well as a few smaller bodies. By studying asteroids, for example, we get a sense of what the Solar System used to look like billions of years ago.
While we think of moons as something that orbits a planet, asteroids also have smaller bodies that orbit them! The first known one was Dactyl, which was discovered in 1993 to be orbiting a larger asteroid called Ida. More than 150 asteroids are known to have moons, with more being discovered periodically. A more recent example is one discovered orbiting Asteroid 2004 BL86, which passed 750,000 miles (1.2 million kilometers) from Earth in early 2015.Asteroids are too important to support life
Also classified as a planetoid, Oseon 5792 was a part of the Fifth Belt, one of the seven wide bands of asteroids that constituted the Oseon system and orbited its sun. The asteroid was registered in a catalog listing the Oseon system's orbital bodies and was situated close to a flock of asteroids that were also well cataloged and easily identifiable.[2]
Once every local year, Oseon 5792, along with every other orbital body in the Oseon system, was affected by a phenomenon known as the Flamewind. Caused by the flares of the Oseon sun tearing excited vapor from the closest asteroids, the Flamewind manifested itself as fluorescent and multi-colored bands of ionized gas millions of kilometers both long and wide that continuously shifted across the entire spectrum of visible light.[2]
Accompanying the visual display were frequent static discharges between the system's asteroids and a constant barrage of radiation and particles, such as electrons. As a result, navigational, sensor, and life-support equipment was damaged, electronic communications between the asteroids and with the rest of the galaxy were made impossible, and the perception and behavior of sentient beings who were not protected by adequate shielding was affected.[2]
Calrissian and Vuffi Raa made an unsuccessful attempt to discern from the Falcon's radiation-damaged navigation computer the asteroid's exact location in the Oseon system. When the droid informed Calrissian of his similarly useless knowledge about the asteroid from the system's astronomical catalog, the captain, assuming that the catalog would have entries on asteroids in Oseon 5792's vicinity, decided that they would simply follow the pre-programmed course to Oseon 5792 as if they had not deviated from it due to the skirmish against the Renatasians and then attempt to correct for the error as they arrived closer to the target asteroid.[2]
As you say, an elevator can fling payloads and thus provide velocity for injection to a transfer orbit. The 2000 km Ceres elevator mentioned above could only provide .5 km/s. Possibly enough to reach neighboring asteroids but not enough to fling a payload earthward. A Ceres elevator 26,000 kilometers tall could provide about 5 km/s, enough for Trans Earth Injection.
For larger asteroids, surface gravity precludes ion engines. While ion engines have great ISP, they have very meager thrust. Even on bodies like Ceres or Vesta, a spacecraft's weight would exceed the tiny thrust of an ion engine. When thrust to weight ratio is less than one, a spacecraft can't get off the ground. However an ion engine could dock with an asteroid elevator.
Where would we find such a slingshot useful? Well, Eros is one of the largest asteroids in the inner solar system. Very few large asteroids have a semimajor axis within Martian territory and Eros is a bit of an exception to the rule. The minimum useful requirement we might expect from it is a Hohmann transfer to/from Earth orbit. I did the calculations before, but you could easily put them together yourself if you want. Even being maximally generous, the time to climb the tether is on the order of months. Since these transfers should only take something like 8 months in the first place this is a huge logistical problem!
What about larger asteroids? For Ceres, Vesta, etc. it could absolutely work. You might have very few constraints on the limit of climbing rate. For these few giants it might be practical to toss things around the asteroid belt.
However, once you've added all these elements, you have almost everything you need for a space trebuchet anyway. It is true that a powered sling would need its own power source (unlike using the asteroid's spin), but doing this would massively reduce the total mass of the structure. For this reason, I think that using the rotation of asteroids for transport is unlikely except for a few very select cases.
If you're aiming at a lonely asteroid, finding one with enough resources to make such construction worthwhile, and rotating in the right plane at the right speed will be exceedingly hard - in particular the first part, resources worth mining, in amounts that make the whole concept economically viable. Doing this for several hundred tons of iron - I don't think we'd find that economically viable in half a millennium.
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