Although I see no sign of it yet on the company’s Web page, British aerospace firm EADS Astrium is designing a spacecraft to be called APEX for a potential mission to an asteroid. APEX is short for Apophis Explorer, naming the target of this interesting payload, which would rendezvous with the tiny asteroid in 2014 and spend three years sending back data on the object’s size, shape, and composition.
Apophis is of more than a little concern, of course, because observations in 2004 suggested a faint possibility that it would hit the Earth in 2029. That scenario has been largely ruled out in favor of a close pass, at 22,400 just slightly nearer than some of our communications satellites. A second flurry of concern has arisen over the possibility of a 2036 strike, but the truly troubling thing about any asteroid this close to us is that its orbit is uncertain. Blame it on the mouth-filling Yarkovsky-O’Keefe-Radzievskii-Paddack effect. As Centauri Dreams has done in previous stories, we’ll shorten that to ‘YORP effect’ and move on.
The YORP effect is a known quantity. It has been determined, for example, that the rotation period of asteroid 2000 PH5 is decreasing by one millisecond every year. Released energy from the effects of solar radiation as the asteroid heats and cools causes the change. Asteroid 1862 Apollo is doing the same thing, gaining rotational speed as the YORP effect kicks in. These are subtle changes, but how near-Earth asteroids like Apophis respond to the YORP effect’s manipulations could be of more than theoretical interest. It could help us determine whether or not an Earth impact is likely at a given point in the future.
We do know that Apophis orbits the Sun every 324 days, during which time it crosses Earth’s orbit twice. We also know that its diameter is some 300 meters, its mass on the order of 27 million tons. The close pass in 2029 will perturb its orbit to some extent, but exactly how this piece of space debris reacts to those changes can only be calculated fully with better information. That makes some kind of asteroid mission a sound investment in our future, if not to Apophis, then to some other rock.
Whether Astrium has the best design may emerge as the company goes after a $50,000 Planetary Society prize. That money would go to charity, the real benefit being to highlight both APEX and the asteroid impact issue in the press. Catching the right committee’s attention is important. With various projects making the rounds — consider ESA’s Don Quijote mission — space agencies may well want to factor in the Astrium design in working out the optimum scenario.
Interesting to see that MP Lembit Opik is campaigning for more funding in this area. He’s the grandson of Estonian astronomer Ernst Opik, a specialist in the study of Earth-crossing comets and asteroids. And the younger Opik recently told the BBC something we all know: “The question isn’t whether Earth is hit by an asteroid – it is when.” Three years in Apophis space might help APEX rule out that source while deepening our store of asteroid information so we’ll be able to make better judgments –and formulate strategies — about other Earth-crossers.
Related: Arecibo’s financial woes, discussed in this Washington Post story, should be front and center in our thinking. An excerpt:
Astronomers from around the country are meeting in Washington this week to highlight the many scientific mysteries that Arecibo is in a unique position to plumb, but the effort may be “too little, too late,” said Daniel Altschuler, a professor of physics at the University of Puerto Rico who was Arecibo’s director for 12 years.
“I don’t see any effective move toward saving Arecibo,” said Altschuler, who calls the observatory “a monument to man’s curiosity.”
Arecibo’s planetary radar is also a monument to man’s self-protection. Are we really going to see it shut down despite the need to continue cataloging dangerous near-Earth objects?
Hi Paul
Seems insane that no one is willing to sustain such a vital resource as Arecibo. What is the NSF wasting its money on? More research on female libido? Do any more “problems” need medicalising and conversion into BigPharma cash cows, or should we be protecting our future???
It’s about time someone took this mission seriously!
After all, finding ways to track (and potentially thwart) asteroids that could hit planetary bodies is going to remain an “on going effort,” not only for our homeworld but for other worlds in our solar system, not to mention other star systems if we are fortunate enough to visit them.
Looking forward to this missions success!
What if they included a little solar driven mass driver on that spacecraft that would nudge Apophis a little bit, to reduce it’s encounter altitude from 22,400 to zero?
Seriously, how much energy would it take to nudge it into the Earth? Is it totally unrealistic? Is Apophis the best chance in the near term to get a spectacular impact onto the Earth?
Arecibo telescope’s global users converge on nation’s capital to plan threatened observatory’s scientific future
http://www.news.cornell.edu/stories/Sept07/AreciboDC.html
Sept. 13, 2007
WASHINGTON, D.C. — More than 70 astronomers gathered on Capitol Hill this week, not to talk about the demise of a major national research facility, but to plan for its scientific future. With optimism, the group was planning the next 15 years of research for Puerto Rico’s Arecibo Observatory, the home of the world’s largest radio telescope.
Despite proposed severe federal budget cuts for the observatory by 2011, the astronomers — users from all over the world — had enough faith to plan for new research and new instrumentation on the 44-year-old telescope.
Funded by the National Science Foundation (NSF) and managed by Cornell’s National Astronomy and Ionosphere Center (NAIC), the observatory already has reduced its current $8 million operating budget by $2 million since last year, and funding will remain level over the next three years. The budget reduction was the result of an NSF Senior Review panel recommendation last year. Administrators at the observatory and Cornell are working to secure funding and keep the telescope working.
The packed meeting on Sept. 12 and 13 — called “Frontiers of Astronomy With the World’s Largest Radio Telescope” — created a scientific case for keeping the 1,000-foot-diameter radio dish as a premier and viable observatory.
“We need to conduct scientific outreach, tell our story and make our points clearly,” said James Cordes, Cornell professor of astronomy and one of the meeting’s organizers.
For two days, the astronomers heard more than 18 hours of scientific presentations. They discussed pulsars, superfluids and time scales; they waxed poetic on exoplanet bursts, gravitational waves, rotating radio transients, magnetic fields and searches for extraterrestrial life. This super brainstorming session sought ideas on exploiting Arecibo’s broad capabilities. And, of course, the astronomers conferred about the possibility of asteroids hitting Earth.
“These presentations were descriptions of opportunities. We learned about the new telescope instrumentation that must be planned now for the future,” said Robert Brown, director of the NAIC.
None of the suggestions will be implemented instantly. However, new instruments might include signal processors and wider band receivers. “Also the astronomers requested more telescope time,” said Brown, noting that Arecibo is currently oversubscribed to projects.
In addition to research, Cornell astronomer Martha Haynes is looking to bolster the observatory’s educational component. “We’re generating this huge data set, and we need more people to help generate research from this data,” she said.
To that effort, Haynes has spearheaded efforts to ensure that faculty and undergraduate students from 14 smaller colleges — such as Colgate, Union, Humboldt State and the University of Puerto Rico — participate in important Arecibo projects. “We have … this great national facility, and we have a duty to help undergraduate students conduct studies at this great observatory,” she said. “If we don’t offer opportunities to undergraduates at smaller colleges, then astronomy will be in danger of being only for the elites.”
Educational labors are serious: Under the direction of astronomy professor Rick Jenet at the University of Texas (UT) at Brownsville, a state-of-the-art, remote control room for Arecibo is being constructed on his campus. It bears an uncanny resemblance to the fictional bridge on the “Star Trek” starship Enterprise. Soon undergraduate and graduate students at UT-Brownsville and local high school students will be able to beam up orders and control Arecibo at designated times.
At the meeting, the message was clear: There is a large volume of work that can be done at Arecibo, now and many years into the future. Said Haynes, “We need to think of clever ways to ensure astronomers have access to the telescope, and we need all hands on deck to get the work done.”
MIT: Asteroid is “practice case” for potential hazards
For Immediate Release FRIDAY, OCT. 12, 2007
Contact:
Elizabeth A. Thomson, MIT News Office
Phone: 1-617-258-5402 Email: thomson@mit.edu
CAMBRIDGE, Mass.–In research that could aid decisions about future asteroids on
a collision course with Earth, MIT researchers have for the first time
determined the composition of a near-Earth asteroid that has a very slight
possibility of someday hitting our planet.
That information could be useful in planning any future space mission to explore
the asteroid, called Apophis. And if the time ever were to come when this object
or another turned out to be on its way toward an impact on Earth, knowing what
it’s made of could be one important factor in deciding what to do about it.
“Basic characterization is the first line of defense,” says Richard P. Binzel,
Professor of Planetary Sciences in the Department of Earth, Atmospheric, and
Planetary Sciences (EAPS). “We’ve got to know the enemy.”
Binzel presented the new findings this week at the annual meeting of the
Division for Planetary Sciences of the American Astronomical Society.
Studying the composition of Apophis has been a useful “practice case,” Binzel
says, because “you never know when the real one will come along” that is on a
collision with the Earth. For determining the composition of a threatening
asteroid, Binzel says, “We don’t know when the real test will come, but we’re
ready.”
On April 13, 2029, Apophis will come relatively close to Earth (it will miss us
by about 22,000 miles). But when it comes by again in 2036, there is a very
small possibility – about one chance in 45,000 – that it could be on a collision
course.
So Binzel, working with EAPS graduate students Cristina Thomas and Francesca
DeMeo and others, has been using telescopes on Earth to find
out as much as possible about the nature of Apophis and other asteroids. Short
of putting together a space mission that would take years and cost hundreds of
millions of dollars, such observations are the best way to find out as much as
possible about any space rock that might someday be coming our way, Binzel says.
Using the MIT Magellan telescope in Chile and NASA’s Infrared Telescope Facility
in Hawaii, they have now been able to figure out exactly what Apophis is made
of. “The composition, I think, is really nailed,” he says.
The key to understanding the mineral makeup of an asteroid is to compare it with
samples of asteroidal material that have been delivered, free of charge, to the
Earth, in the form of the many thousands of meteorites that have been collected
over the years.
Spectral analysis – measuring how the meteorites reflect light of different
wavelengths – can be used to determine their exact mineral constituents.
Similarly, a spectral analysis of the light reflected from a distant
asteroid shows the same telltale lines that reveal its composition. By comparing
the two kinds of spectra, an asteroid that is just a faraway pinprick of light
can be correlated with a piece of a space rock in the laboratory.
Binzel and his students were able to use both visible-light and infrared
spectroscopy to show that Apophis is “a good match” for a rare type of
meteorite, known as a type LL chondrite. These represent just 7 percent of the
known meteorite falls on Earth, and are rich in the minerals pyroxene and
olivine, which are also common on Earth.
“The beauty of having found a meteorite match for Apophis is that because we
have laboratory measurements for the density and strength of these meteorites,
we can infer many of the same properties for the asteroid Apophis itself,”
Binzel says.
An object the size of Apophis (about 270 meters across) could devastate a region
as large as France, or produce tsunamis over a wide area if it struck at sea.
Many
ideas have been proposed for how to deal with
such a threat, ranging from using bombs, lasers or spacecraft to nudge it out of
the way to blowing it to pieces while it is still far away. The selection of the
best course of action may depend of the physical characteristics of the object,
including its mineral composition.
–END-
Written by David Chandler, MIT News Office
“Foresight” Wins First Prize in Apophis Asteroid Tagging Competition
The Near Earth Asteroid (NEO) Apophis is expected to flyby
the Earth in 2029. However, this flyby will be more of a “fly-
very-close” as the lump of rock will miss the Earth by only a
few thousand kilometers.
This near-miss isn’t worrying scientists too much, but should
the asteroid tumble through a 400 meter gravitational “keyhole”,
there is concern that the asteroid could swing by and risk
another collision in 2036. Although the odds are fairly slim,
astronomers need better precision in calculating Apopis’s orbital
trajectory.
How can this be done? Why not send a spaceship to shadow the
asteroid on its journey? The Planetary Society has announced
just that. The winning design of the Apophis Mission Design
Competition will send a probe and tag Apophis to gain more
details about this interplanetary vagabond, and has been
awarded a healthy $25,000 to help the development of the
US “Foresight” mission…
http://www.universetoday.com/2008/02/26/foresight-wins-first-prize-in-apophis-asteroid-tagging-competition/
Big Asteroid Less Likely to Hit Earth
The large asteroid Apophis is less of an impact threat to Earth that previously thought, new research finds.
http://www.space.com/scienceastronomy/091007-apophis-hazard.html