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2007/1/24 
HONOLULU - NASA astronaut Edward Lu is campaigning for a new spacecraft that would divert asteroids on a path to slam into Earth.
The small space tractor, costing between $200 million and $300 million, would hover near an asteroid to exert enough gravitational pull that the space rock's orbit would change and a collision with our planet would be averted, Lu told an audience at the University of Hawaii-Manoa Monday night.
"We're only trying to get a really tiny change in the velocity of the asteroid to prevent an impact," said Lu, a former University of Hawaii solar physicist.
Read More...
Astronaut touts asteroid-bumping mission - Space News - MSNBC.com 2006/6/30 
NEO News (06/30/06) XP14 & NASA NEO
Workshop
This edition of NEO News briefly discusses asteroid 2004 XP14, which
on July 3 will be the best NEO radar target ever. However, most of the
material below deals with the Congressional request to NASA to plan a
new NEO program for the discovery, characterization, and defense
against sub-km NEAs. There are two reports from the NASA NEO Workshop
held this week in Colorado to study options for Discovery,
Characterization, and Hazard Mitigation, down to NEAs with diameter
140 m. Also included is the text of the relevant Congressional request
to NASA.
David Morrison
============================
CLOSE PASS JULY 3 BY 2004 XP14
On July 3, 2006, our planet will receive a close visit by Near Earth
Asteroid (NEA) 2004 XP14, which will pass by at 1.1 times the distance
to the Moon (a little more than 400,000 km). This NEA was discovered
in 2004 but was only recovered last week. There is no risk of its
hitting either the Earth or the Moon, but it is unusually well placed
for study, especially by radar. The asteroid will swing past us at a
relative speed of 17 km/s.
While XP14 will not be visible to the unaided eye, its relatively
large size (estimated at roughly half a kilometer) combined with its
closeness makes it one of the best-placed targets for study in the
history of planetary radar. Extensive observations are planned with
the NASA 70-m radar at Goldstone, California, which is part of the
NASA Deep Space communications network. It is anticipated that these
radar studies will yield detailed images of the asteroid, as well as
highly precise values for its orbit and spin state. Many NEAs have
recently been found to have satellites, and the presence of a
satellite will also be looked for with the radar.
This close pass by such a large asteroid has little historical
precedent, but calculations show that a NEA this large comes this
close about once per decade on the average. However, similar close
passes in the past were not observed, since it is only in the past
decade that the Spaceguard Survey has begun to inventory NEAs in this
size range.
===========================
NASA NEO WORKSHOP
By David Morrison
On June 26-29, nearly one hundred scientists, engineers, astronauts,
and managers from NASA, industry, and academia met in Colorado for an
informal workshop to discuss how best to respond to NASA's new
Congressional mandate to survey and characterize sub-km-diameter NEAs
in order to understand and mitigate the threat of impacts by such
objects. Following the model of the current Spaceguard Survey, which
has a goal to discover 90 percent of NEAs larger than 1 km by the end
of 2008, the new request from Congress is for NASA to develop a
program to discover 90 percent of the NEAs larger than 140 m by 2020.
The value of 140 m was derived in a 2003 NASA study that estimated
that 90 percent of the risk of unpredicted impacts from sub-km NEAs
could be eliminated (or retired) by extending the Spaceguard Survey
down to 140 m diameter. (Full Congressional text is at end of this
report).
Discussions at the NEO Workshop were grouped into three general
topics: Discovery, Characterization, and Hazard Mitigation. In the
areas of Discovery and Characterization, the presentations were about
equally divided between techniques involving ground-based astronomy
and those that required access to space. For example, both
ground-based telescopes and space-based telescopes were described that
suggested they could meet the 90 percent goal of 140 m and larger
NEAs. In the area of characterization, suggestions were made for
broadly-based surveys that could provide some additional information
for a substantial fraction of the newly discovered NEAs, for surveys
to characterize a small subset of these, and for approaches to be used
for intense investigation of any NEA that might appear to be a real
hazard. The techniques included ground-based telescopes, space-based
telescopes, and missions to visit individual NEAs with spacecraft to
orbit or land on the surface. Prominently discussed were recent
results from the Japanese Hayabusa mission to asteroid Itokawa, the
first sub-km NEA to be visited by spacecraft. (A series of technical
papers describing Itokawa were just published in the June 6 issue
of Science). Under Hazard Mitigation, almost all discussions
assumed the requirement to actually deflect an asteroid on a collision
course with Earth. Also receiving attention were issues of how much
lead time we are likely to have, and under what circumstances
different deflection techniques might be used. Prominent were the
cases of Apophis, which has a low-probability of impacting in 2036,
and 2004 VD17, with a low-probability impact in 2102 (see the NASA NEO
Program webpage
http://neo.jpl.nasa.gov for current
information on these and the other 4000 known NEAs)
The shift from emphasis on the NEAs larger than 1 km to the sub-km
NEAs is a major one. The Spaceguard Survey has already discovered more
than 75 percent of those larger than 1 km, and none is on a collision
course. However, there are only about 1100 NEAs this large. In
contrast, the number of NEAs larger than 140 m is approximately
100,000, and there may be as many as a million that are as large as
the object that produced the Tunguska explosion in 1908. Discovery
rates in the new surveys will have to be 100 times faster than the
current Spaceguard System, and the orbit calculations and archiving of
data will scale in the same way. As the survey progresses, many more
potential targets for spacecraft missions will also be identified.
However, these are at present just hopes and plans; a new survey has
not yet been approved, nor any funds appropriated to support it. A
formal report from NASA to the Congress will be made later this
year.
==============================
ASTEROID DEFENSE: NASA TO FORMULATE PLANETARY PROTECTION PLAN
By Leonard David
Senior Space Writer
Space.com, 28 June 2006
NASA has begun a fact-finding appraisal of how best to detect, track,
catalogue and characterize near-Earth asteroids and comets -- and what
can be done to deflect an object found on course to strike our planet.
The need to prepare is highlighted this week as astronomers watch a
large asteroid that will pass close to Earth on July 3.
Selected experts from a variety of fields are here this week at a NASA
workshop on Near-Earth Object (NEO) Detection, Characterization and
Threat Mitigation. The meeting is a unique, "idea gathering"
event being carried out under direction of the U.S. Congress. The
intent is to provide lawmakers with an "executable program"
-- but also one that will clearly need funds to implement that program
in an orderly and timely fashion.
NASA is on a fast-track to provide by year's end an initial report to
Congress that includes an analysis of possible alternatives that might
be employed to divert an object on a likely collision course with
Earth.
The U.S. Congress has tagged NASA to use its "unique competence"
to deal with the potential hazard faced by Earth from such celestial
wanderers, in order to help establish a warning and mitigation
strategy.
Another chief agenda item on the table is putting in place the survey
skills to spot NEOs equal to or greater than 460 feet (140 meters) in
diameter. In plotting out that survey program, the merits of
ground-based and space-based equipment are to be mulled over to
achieve 90 percent completion of a NEO catalogue within 15 years.
This week's gathering is viewed by many as a turning-point in shaping
a NEO action plan. "It is historic in the sense that it's the
first time the U.S. government has ever had a formal interest in the
problem, in the global problem, that is, in the detection, tracking
and beginning to look at the mitigation issues. I think that's very
significant," said William Ailor of The Aerospace Corporation and
on the workshop's mitigation working group.
Similar in view was Russell Schweickart, former Apollo astronaut and
Chairman of the B612 Foundation. This group consists of scientists,
technologists, astronomers, astronauts, and other specialists that
want to significantly alter the orbit of an asteroid in a controlled
manner by 2015.
"This is really the first time that NASA will have ever put the
words NASA and asteroid deflection together internally ... so it's a
very positive move," Schweickart told SPACE.com in a pre-workshop
interview. He later advised workshop participants that "this
isn't a national issue...this is a planetary issue." Schweickart
added that, given the likely scenario of decades of warning time,
"this is not a last minute search and destroy mission."
There's been no shortage of ideas how to fend off unfriendly fire from
the cosmos: laser beams, space tugboats, gravity tractor, and solar
sails for example, as well as using powerful anti-NEO bombs,
conventional as well as nuclear.
Ailor, also Director of The Aerospace Corporation's Center for Orbital
and Reentry Debris Studies, told SPACE.com that creative ways to
deflect Earth-harming NEOs are far from being exhausted.
"People have put a lot of concepts on the table over time,"
Ailor said. "Now we're beginning to try and develop an organized
way of looking at those things and finding out which ones are really
viable in the short-term, medium-term, and what technologies do we
need to protect and develop for the long-term as well."
A key message early in the workshop is that detection of NEOs is a
first priority. The on-going, three-part mantra agreed to by attendees
is simple and direct: "Find them early...and find them
early...and find them early."
A likely setting is one where a modest Earth impact probability by a
NEO is identified decades in advance, then, future mitigation
technologies would be most appropriate. Furthermore, "opportunity
science" could be derived from such a response. NASA has an
interest in harvesting NEOs for their minerals as well as siphoning
from them water to further long-range space exploration goals.
Former shuttle astronaut Tom Jones, taking part in the meeting, has
had a long-standing interest in asteroids and told SPACE.com:
"The NEO workshop this week is both informative -- with the
latest NEO data presented by experts in the field -- and encouraging
as the space agency seems intent on developing realistic alternatives
for detecting most of the potentially hazardous NEOs. That's good ...
Congress expects NASA to answer the mail on how to deal with NEOs.
This meeting is an important move forward in beginning to materially
address the hazard."
As if a warning shot of sorts, several workshop attendees made note of
next week's close flyby of Earth of asteroid 2004 XP14. Discovered in
late 2004, the space rock will slip by Earth on July 3, passing just
beyond the Moon's average distance from Earth.
==========================
CONGRESSIONAL TEXT ON NEW NEO PROGRAM
"The U.S. Congress has declared that the general welfare and
security of the United States require that the unique competence of
NASA be directed to detecting, tracking, cataloging, and
characterizing near-Earth asteroids and comets in order to provide
warning and mitigation of the potential hazard of such near-Earth
objects to the Earth.
The NASA Administrator shall plan, develop, and implement a Near-Earth
Object Survey program to detect, track, catalogue, and characterize
the physical characteristics of near-Earth objects equal to or greater
than 140 meters in diameter in order to assess the threat of such
near-Earth objects to the Earth. It shall be the goal of the survey
program to achieve 90 percent completion of its Near-Earth Object
catalogue (based on statistically predicted populations of near-Earth
objects) within 15 years after the date of enactment of this Act.
The NASA Administrator shall transmit to Congress not later than 1
year after the date of enactment of this Act an initial report that
provides the following:
(A) An analysis of possible alternatives that NASA may employ to carry
out the Survey program, including ground-based and space-based
alternatives with technical descriptions.
(B) A recommended option and proposed budget to carry out the Survey
program pursuant to the recommended option.
(C) Analysis of possibly alternatives that NASA could employ to divert
an object on a likely collision course with Earth."
--
David Morrison, NASA Ames Research Center 240-1
Tel 650 604 5094; Fax 650 604 4251; Cell 650 278 0343
david.morrison@nasa.gov or dmorrison@arc.nasa.gov
website: http://nai.arc.nasa.gov
website: http://impact.arc.nasa.gov
Quote
NEO News (06/30/06) XP14 & NASA NEO
Workshop
OnLine Here: NEO News (06/30/06) XP14 and NASA NEO Workshop
2006/5/14
Michael Cabbage
Sentinel Space Editor
May 14, 2006
CAPE CANAVERAL -- Mark your calendar for Sunday, April 13, 2036. That's when a 1,000-foot-wide asteroid named Apophis could hit the Earth with enough force to obliterate a small state.
The odds of a collision are 1-in-6,250. But while that's a long shot at the racetrack, the stakes are too high for astronomers to ignore.
For now, Apophis represents the most imminent threat from the worst type of natural disaster known, one reason NASA is spending millions to detect the threat from this and other asteroids.
A direct hit on an urban area could unleash more destruction than Hurricane Katrina, the 2004 Asian tsunami and the 1906 San Francisco earthquake combined. The blast would equal 880 million tons of TNT or 65,000 times the power of the atomic bomb dropped on Hiroshima.
Objects this size are thought to hit Earth about once every 1,000 years, and, according to recent estimates, the risk of dying from a renegade space rock is comparable to the hazards posed by tornadoes and snakebites. Those kind of statistics have moved the once-far-fetched topic of killer asteroids from Hollywood movie sets to the halls of Congress.
"Certainly we had a major credibility problem at the beginning -- a giggle factor," said David Morrison, an astrobiologist at NASA's Ames Research Center in Mountain View, Calif. "Now, many people are aware this is something we can actually deal with, mitigate and defend against."
In 1998, lawmakers formally directed NASA to identify by 2008 at least 90 percent of the asteroids more than a kilometer (0.6 mile) wide that orbit the sun and periodically cross Earth's path. That search is now more than three-quarters complete.
Last year, Congress directed the space agency to come up with options for deflecting potential threats. Ideas seriously discussed include lasers on the moon, futuristic "gravity tractors," spacecraft that ram incoming objects and Hollywood's old standby, nuclear weapons.
To help explore possible alternatives, former Apollo astronaut Rusty Schweickart has formed the B612 Foundation. The organization's goal is to be able to significantly alter the orbit of an asteroid in a controlled manner by 2015.
"You can watch all of the golf on television you want, but if you want to go out and break par, it's going to take a lot of playing," Schweickart said. "And you're going to learn a lot that you thought you knew, but you didn't."
Cosmic collisions
Throughout their 4.5 billion-year history, Earth and its neighboring planets have been like sitting ducks in a cosmic shooting gallery.
A glance at our moon shows the scars left by countless collisions with asteroids and comets. In fact, the moon is thought to have been created when part of the early Earth was ripped away in a cosmic impact with an object the size of Mars.
Earth also has scars, but most have been hidden by vegetation or eroded by geologic processes such as rain and wind. About 170 major impact sites, including northern Arizona's 4,000-foot-wide Barringer Crater, have been identified around the globe.
Within the past century, an extraterrestrial chunk of rock about 200 feet wide is thought to have caused a 1908 blast near Tunguska, Siberia, that leveled 60 million trees in an area the size of Rhode Island. Researchers theorize the object exploded four to six miles above the ground with the force of 10 million to 15 million tons of TNT.
Few outside scientific circles took the threat posed by near-Earth objects seriously until 1980. Then, Luis and Walter Alvarez published a study based on geologic evidence that concluded a cataclysmic asteroid or comet impact 65 million years ago caused the mass extinction of two-thirds of all plant and animal life on Earth -- including the dinosaurs.
Dubbed the Great Exterminator, the colossal object was estimated at 7 miles in diameter and created a blast hundreds of millions of times more destructive than a nuclear weapon. Objects that size are thought to hit Earth about every 100 million years.
NASA scientists studying satellite photos bolstered the Alvarezes' theory with the discovery in 1991 of an impact crater 125 miles wide buried beneath the northwestern corner of Mexico's Yucatan Peninsula. Three years later, NASA photos of another sort drove home the potential for cosmic collisions in our part of the solar system.
Spectacular images from the Hubble Space Telescope of Comet Shoemaker-Levy's collision with Jupiter showed 21 comet fragments, some more than a mile wide, producing colossal fireballs that rose above the giant planet's cloud deck.
"I think the most important development for getting this [public awareness] going was the Alvarezes' research that the dinosaurs went extinct as the result of an impact," Morrison said. "We were faced with a real example where an impact had done terrible damage."
Tracking the threats
In 1998, a year in which the asteroid-disaster flick Armageddon was the top-grossing movie worldwide, Congress held hearings that led to the creation of a Near Earth Object Program office at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
That year marked the beginning of the Spaceguard Survey aimed at discovering 90 percent of near-Earth asteroids more than a kilometer wide.
Today, astronomers at five primary U.S. sites work on the survey, which NASA funds with about $4 million annually. Scientists estimate there are 1,100 near-Earth asteroids that are larger than a kilometer wide. With two years to go, they have found 834, or about 76 percent, of the estimated total.
Congress directed NASA in December to look at expanding the search to asteroids larger than 140 meters (460 feet) in diameter and completing the new survey by 2020. Objects that size are capable of destroying a city.
The more often an asteroid or comet is sighted, the more precisely its orbit can be calculated. Researchers hope that radar observations of Apophis taken last weekend by the Arecibo telescope in Puerto Rico could make the odds of a collision even more remote.
"I always use the analogy of a hurricane," said Don Yeomans, manager of the Near Earth Object Program. "When it first forms in the Caribbean, you have no idea where it's going to hit. If you continue to track the hurricane over days and weeks, the future path becomes more predictable."
That uncertainty led former astronaut Schweickart to send a letter to NASA Administrator Michael Griffin last June proposing to land a radio transponder on Apophis to better track its course. For now, the space agency plans to simply monitor the asteroid during passes this year and in 2013.
In 2029, seven years before the possible impact, the asteroid will come closer to our planet than the television and weather satellites that beam back signals from 22,300 miles above. Astronomers' big fear is that Apophis will pass through a gravitational "keyhole" that will put it on a collision course with Earth in 2036. "For all practical purposes, it [a mission] would have to be done before the 2029 flyby to take advantage of the leverage afforded by that encounter," said Steve Chesley, an astronomer in the Near Earth Object Program. "That means the 2036 impact needs to be addressed by 2026, 10 years earlier."
Defending the planet
There is considerable debate about how to stop an asteroid or comet once astronomers have determined it will pass too close for comfort.
One idea would use a laser cannon on the moon or atop a spacecraft to shift the threatening object's course. Another involves slamming a spaceship into the object to nudge it away. A slight push a decade or so before a possible collision would translate into a wide miss years later.
Astronauts Ed Lu and Stanley Love published an idea last year for a "gravitational tractor" to change an asteroid's orbit. A nuclear-powered spacecraft would be launched toward the rock and hover near it, using gravity to slowly divert the intruder.
A fallback option using readily available technology involves detonating a nuclear weapon near the threat to shove it off course. It might be the only alternative if an object is discovered only a few months before impact.
Most experts agree the response will depend on the specific threat.
"You have to discover and know your enemy before you can even imagine what kind of mission or deflection you would do," Morrison said.
In recent months, some of the larger political questions are starting to be widely discussed.
If the Earth is threatened, NASA almost certainly would help lead the response. But who ultimately makes the decision on how to proceed? The United States? The United Nations? What about cases where deflecting an object away from an endangered region might move its course across another area? And how likely does a threat have to be to warrant taking action?
Schweickart is convinced those sorts of decisions should be made by the entire planet. He has begun work on a draft treaty he hopes to present to the United Nations by 2009.
As for Apophis, NASA scientists are confident the knowledge they've gained will prevent the asteroid from becoming the next cosmic catastrophe.
"Apophis is not going to hit the Earth. Period," Chesley said. "Whatever the impact probabilities that we compute right now are, we're not going to let it."
Michael Cabbage can be reached at mcabbage@orlandosentinel.com or 321-639-0522.
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Space rock could make 2036 a killer year - Orlando Sentinel : News Space rock could make 2036 a kill
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