Monday, August 15, 2005

NEO Updates: Japan Pitches In, Spaceguard 75% Complete, Apophis Makes the News......


We have a nice little bundle of NEO news lately, I'll give the brief synposis...

Hayabusa's Contributions Toward Understanding the Earth's Neighborhood

Don Yeomans
August 11, 2005

Beginning in early September 2005, the Japanese Hayabusa spacecraft will rendezvous with near-Earth asteroid (25143) Itokawa. Itokawa, a 600 meter sized, potato-shaped asteroid, is named after Hideo Itokawa, a Japanese rocket pioneer. Although the primary objectives of the Hayabusa mission are to test new technologies, the mission will also provide a wealth of scientific returns. For the three month period from September through November 2005, the science instruments on board the Hayabusa spacecraft will undertake an intensive study of near-Earth asteroid Itokawa. After closely observing the asteroid for several weeks, a few pellets will be fired from the spacecraft at close range into the asteroid's surface and about a gram of the pellet's impact ejecta will be collected into a sample capsule. This capsule will then be brought back to Earth and parachuted into the Australia outback in June 2007 so that some of the asteroid's surface minerals can be studied in Earth-based laboratories. This will be the first asteroid sample return mission.

It is comforting to see a country like Japan take a leading role in helping to improve our understanding of NEO's. If anything, there needs to be world wide cooperation on this issue, and the more countries get involved the better.

Yeoman continues-

Hayabusa's observations will address each of three major issues concerning asteroids:

1.) their role as the building blocks of the solar system, 2.) their potential for impacting Earth and 3.) their future use as raw materials for building space structures.

1.)The scientific interest in asteroids is due largely to their status as the remnant debris from the inner solar system formation process that occurred some 4.6 billion years ago. Since the chemical compositions of asteroids have remained relatively unchanged since their formation, knowledge of their elemental makeup would provide an understanding of the chemical mix from which the inner planets, including Earth, formed.

2.)From time to time, near-Earth asteroids collide with Earth. Should one of them be found upon an Earth threatening trajectory, scientists would need to understand its composition and structure before a successful strategy could be undertaken to deflect the object away from Earth.

3.)Some of the near-Earth asteroids that are potentially the most hazardous because they can closely approach the Earth are also the objects that could be most easily reached and exploited for raw materials. The minerals, metals and water ices on near-Earth asteroids and comets could be used to manufacture the space structures and rocket fuel that will be required to explore and colonize our solar system in the 21st century. We need to examine the chemical composition of some of these objects to understand which among them are richest in mineral wealth and other raw materials.

Domo Arigato Hayabusa Team! The Hayabusa site is here, and will soon be added to ye 'olde blogroll to your right.

Here is the latest on the Spacegaurd survey, which is supposed to be completed by 2008.


David Morrison

Next month, the number of known near-Earth asteroids (NEAs) larger than 1 km diameter (or, more precisely, brighter than absolute magnitude 18) should pass the 800 mark. As of August 8 the NASA NEO Program Office website [] listed 793. The total number of NEAs discovered as of that date is 3496.

If the population of NEAs larger than 1 km is 1100, 800 represents 73 percent completeness. It is interesting to note that 800 is already more than the total number of NEAs larger than 1 km predicted in some analyses carried out just a few years ago. For the metric of the Spaceguard Survey, which aims to find 90 percent of NEAs larger than 1 km, we are now more than 80% of the way to that goal.

The recent pattern of discovery also shows an expected drop in the discovery rate for the larger NEAs. As the survey becomes more complete, there are fewer large NEAs to be found and a larger fraction of those detected are rediscoveries of asteroids already catalogued. The total number of NEAs larger than 1 km found each year has declined since 2000, with annual totals through 2004 of 131, 91, 101, 69, and 57.

The good news is that they have made significant progress in terms of the survey, and as noted the total number of NEAs larger than 1 km found each year has declined since 2000, which means we have ruled out the majority of the asteroids in our solar system that would cause a global climatic catastrophe that may threaten the future of civilization as we know it. The bad news is that asteroids smaller than but not quite 1 km in size would still cause serious damage -not quite civilization ending- but large enough to kill millions of people in an instant. These asteroids are much more difficult to detect, but we would have a better chance of successfull mitigation. In other words, scrap the damn ISS and the Space Shuttle, and get to work on the B612 Project. Like now.

Also, the asteroid formerly known as 2004 mn4, Apophis, made the editorial page of the New York Times two weeks ago, and the Time Magazine online page last week. Both of these articles can be read at the following link here to the Nasa Asteroid and Comet Impact Hazard page.

Here is the crucial bit from the Time Magazine page. Discussing Apophis, both David Morrison and Rusty Schweikart comment on the urgency in regards to tracking our friendly killer rock-

Why the rush? The Apophis deflection, should it become necessary, must take place before the 2029 close approach. Earlier than that, just a simple nudge, accomplished, say, by firing a heavy object at the asteroid, could change its course enough to miss the crucial but small keyhole. Any time after that approach, should Apophis pass through the keyhole, we could be in trouble. NASA scientist David Morrison explains: "After 2029, the deflection would have to be vigorous enough to miss not just a tiny keyhole but the much larger target of the Earth itself. And such a deflection is far beyond present technology for an asteroid this large."

Given that deadline, some 24 years from now, there's seemingly plenty of time to take action. But Schweikart, who admits he is not expert in mission planning, speculates that a transponder mission, from initial planning to implantation might take, say, eight years. And he thinks that a following deflection attempt, if it proves necessary, could require as long as 15 years to implement. That's cutting it a little close, and, says Schweikart, all the more reason that NASA quickly calculate some realistic mission times. "It may turn out," he says, "that we have to begin planning those missions right now."

Better safe than sorry folks. Yes, I think it's fascinating that there may be frozen water on Mars. No, I don't think that should take priority over protecting the planet from a potentially catastrophic impact. Let's hope the $16 billion budget at NASA will start to be used in a more pro-active way.

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