A pixelated profile from NASA's Goldstone radar dish makes the passing asteroid 2012 DA14 look a bit like an out-of-control Viper space fighter from "Battlestar Galactica." But the real-life asteroid is almost five times as big, and might well pack a bigger wallop if it ever hit our planet.
NASA's Jet Propulsion Laboratory on Tuesday released a movie combining 73 radar images of 2012 DA14, captured over the course of eight hours on the night of Feb. 15-16. The image resolution is 13 feet (4 meters) per pixel.
In a news release, NASA said the images show the roughly 130-foot-long (40-meter-long) asteroid moving away from us, at a distance ranging from 74,000 miles to 195,000 miles (120,000 to 314,000 kilometers). These readings were made just hours after the time of closest approach, when the asteroid came within 17,200 miles (27,680 kilometers) of our planet.
2012 DA14's close encounter on Feb. 15 was eclipsed by the nuclear-scale impact of a meteor over the Russian city of Chelyabinsk earlier in the day — a widely witnessed event that caused more than 1,200 injuries and did an estimated $33 million in damage. NASA said the asteroid behind Russia's meteoric display was about a third the size of 2012 DA14.
If 2012 DA14 had hit instead, the damage would have been much, much worse. Experts have compared the bigger space rock to the object that blew up over a Siberian forest in 1908, knocking down millions of trees over an 820-square-mile area. As it is, the Russian meteor rates as the biggest observed cosmic impact since Siberia's Tunguska event.
JPL's radar observations, which continue through Wednesday, are aimed at fine-tuning the calculations of 2012 DA14's future orbit by getting a better fix on its size, shape, rotation, surface features and surface roughness. For what it's worth, the asteroid's estimated length of 40 meters along its long axis is between four and five times the length of the Colonial Viper spacecraft that buzzed the Cylons in the "Battlestar Galactica" TV series.
The asteroid's path was perturbed by Earth's gravitational field in such a way that it won't come as close in the foreseeable future. However, a better understanding of its orbit and its composition could help scientists prepare for encounters with other asteroids — and figure out the best way to divert potentially threatening near-Earth objects.
The radar observation campaign is led by JPL's Lance Benner and Marina Brozovic.
Here are a more views of 2012 DA14 from other observers:
An international team led by MIT's Nicholas Moskovitz observed asteroid 2012 DA14 with a number of telescopes, including the 2.1-meter telescope at Kitt Peak National Observatory. This animated image shows the asteroid as it was leaving Earth's vicinity. Check out the National Optical Astronomy Observatory's news release for more information. If you missed seeing the animation, click here for a refreshed view.
Since its historic landing on Mars, the Curiosity rover's mission has been followed by the whole world. One of the mission's team members took a creative approach to balancing work and family by living on "Mars time."
A California family's journey on Mars time had its ups and downs, but NASA flight director David Oh says he's glad he took his wife and kids on the ride.
"My kids loved it, I loved it, and I think it served to bring the family together," Oh told NBC News on Friday.
Oh is one of the flight directors for NASA's $2.5 billion Mars Science Laboratory mission, which sent the Curiosity rover on a two-year quest to determine whether the Red Planet ever had the chemical ingredients required for life as we know it. Each Martian day, or sol, is 39 minutes and 35 seconds longer than an Earth day. So, to stay in sync with the mission's initial phase, the team at NASA's Jet Propulsion Laboratory in Pasadena, Calif., was put on a Martian schedule for the first 90 sols.
That meant that Oh's workday quickly fell out of sync with Earth time. To make it easier on himself, and on his wife and three children, the Oh family decided to spend 30 sols on Mars time.
"The kids weren't going to get to see Daddy for long periods of time," Oh's wife, Bryn, said. "It just seemed like the right thing to do,"
The time warp meant that the family dinner could take place at 4 p.m. PT, or 4 a.m., depending on how the Martian day meshed with their earthly schedule. But it also meant the Oh children — 13-year-old Braden, 10-year-old Ashlyn and 8-year-old Devyn — had lots of quality time to learn about what Dad is doing.
"Curiosity's mission is to go try and find life on another planet, which is totally cool," Ashlyn Oh said.
David Oh said the rest of the family switched back to Earth time in September, a month after Curiosity's landing, to get into sync with the school schedule. "It really felt like we all had gone off on a journey, and we came back," he recalled. But the tough part of Oh's journey was just beginning: He had to stay on Mars time for an additional 60 sols, and during that period he struggled to juggle his work duties and family time. He remembered some days when he got just four hours of sleep at a time.
"I was in a state of continual jet lag for the last couple of months," he said.
Finally, in November, Curiosity's mission team shifted back en masse to an Earth-day schedule. It took Oh a couple of days to adjust, but now he's firmly back on an earthly schedule. The kids are clamoring to live on Mars time again — but that's one trip Oh doesn't plan to repeat anytime soon.
Apophis, nicknamed the "Doomsday Asteroid," was once considered a potential threat, but now scientists realize the chance of the asteroid colliding with Earth is negligible. NBC's Brian Williams reports.
Radar observations made during this week's close encounter with the asteroid Apophis have ruled out the risk of a catastrophic cosmic collision in 2036, NASA says. Experts say it'll be much farther away at that time than it is right now.
The crucial readings came on Wednesday when the space rock, which is thought to measure at least 885 feet (270 meters wide), approached within 9 million miles (14.5 million kilometers) of Earth. NASA is monitoring Apophis with its 230-foot (70-meter) Goldstone radio dish in California. Optical readings also have come in from the Magdalena Ridge Observatory in New Mexico and the Pan-STARRS observatory in Hawaii.
The bottom line? "We have effectively ruled out the possibility of an Earth impact by Apophis in 2036," Don Yeomans, manager of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory, said today in the all-clear news release. "The impact odds as they stand now are less than one in a million, which makes us comfortable saying we can effectively rule out an Earth impact in 2036. Our interest in asteroid Apophis will essentially be for its scientific interest for the foreseeable future."
Jon Giorgini, who developed JPL's online Horizons database to keep track of solar system objects, would go even further. He says that according to calculations based on the Goldstone data, Apophis will probably pass by Earth at a distance of 36 million miles (58 million kilometers, or 0.39 AU), and absolutely no closer than 14 million miles (22 million kilometers, or 0.15 AU). "That is a very extreme minimum," he told NBC News. "Nothing else plausible can get you closer."
Apophis, a.k.a. 2004 MN4, created a huge splash when it was discovered in 2004 because the initial assessment of its orbit gave a 1-in-40 chance of Earth impact in 2029. That would be catastrophic: The space rock is big enough to wipe out a city if it struck land, or create killer tsunami waves if it splashed into the ocean.
Additional orbital data quickly eliminated the risk for 2029, but showed that it would pass within 20,000 miles (32,000 kilometers) of our planet at that time. That's so close that Earth's gravitational field will perturb Apophis' orbit. The experts worried that if the asteroid passed through a particular half-mile-wide zone in space, known as a "keyhole," its orbit would be perturbed just enough to set up a smash-up during the 2036 encounter. Fortunately, the latest observations indicate that Apophis will miss the keyhole by a long shot.
Did I just hear a cosmic sigh of relief?
UH / IA
The asteroid Apophis, highlighted here by a white circle, was discovered in June 2004.
There are still a few uncertainties surrounding Apophis: Astronomers don't yet have enough data to determine how the asteroid is spinning or how solar radiation is affecting its orbital path — a phenomenon known as the Yarkovsky effect. Giorgini said that even under the worst-case scenario, the effect won't push Apophis into a collision in 2036. But there could conceivably be other risky encounters in the decades or centuries ahead.
"There's a non-linear amplification that can really move it around more," Giorgini said.
Also, there are questions about Apophis' exact size. Just this week, readings from the European Space Agency's Herschel space telescope suggested that the asteroid may be nearly 20 percent bigger than previously thought. But that larger size estimate is based on the assumption that Apophis is a spheroid, and astronomers already know that it's elongated.
"We're not seeing that larger size in the radar data," Giorgini said.
By the end of next month, continued radar observations from Goldstone as well as the Arecibo Observatory in Puerto Rico should give astronomers a much better fix on Apophis' spin and its size. When those factors are fully accounted for, the Jet Propulsion Observatory will update its official risk assessment for Apophis — and could take this bad boy off the hit list for good.
Update for 6:30 p.m. ET: Clark Chapman, senior scientist at the Southwest Research Institute, weighed in on the current state of the asteroid hunt in an email:
"One thing you should be aware of, and might mention, is that the next Planetary Defense Conference, an every-two-year international meeting, will be held April 15-19 in Flagstaff, Arizona. ... Some presentations are already listed in the program, which should be finalized a week from now, which is the due date for abstracts.
"An interesting tie-in with the new observations of Apophis is that a similar thing happened with 2011 AG5 a few weeks ago, when observations with the huge Gemini telescope in Hawaii showed that it would, in 2023, miss the roughly 350-km-wide 'keyhole' and, therefore, not strike the Earth in 2040. Prior to these critical observations, the chance of a 2040 impact was unusually high (though still low in everyday terms) at 1 in 500.
"A point to be realized is that while the chances of impact in these cases are very low by ordinary standards, they aren't zero, and the consequences of an impact could be very terrible, so it is important to plan and prepare for the possibility of impact until it is ruled out.
"It was important to get these observations of AG5 in the autumn of 2012, because if it had turned out that AG5 was actually on an impact trajectory, it would have given us an additional year to mount a deflection mission and succeed in deflecting it from the 2023 keyhole. Without making a major observational effort with a very large telescope this autumn, the next routine observational opportunity wasn't until this coming autumn."
Update for 8:30 p.m. ET: One of NASA's experts on the asteroid threat and two former NASA astronauts have weighed in on the report about Apophis. David Morrison of NASA's Ames Research Center sent these comments via email:
"One possible angle is the recent proposal from [NASA Administrator] Charlie Bolden, based on a Keck study, that we retrieve a 7-meter carbonaceous near-Earth asteroid and bring it into lunar orbit. There are many questions about this idea, but the one I have in mind is our assumed ability, without Sentinel, to find 7-meter C-type asteroids in Earthlike orbits. If you can't find them, you can’t protect against them, or do anything with them as potential resources."
Now here's an email from Ed Lu, a veteran of two space shuttle missions and an extended stay on the International Space Station. Lu now serves as chairman and CEO of the B612 Foundation, which is planning to launch the Sentinel space telescope to track half a million near-Earth asteroids:
"While it is great that Apophis is much better understood, and we know it won't hit us in 2036, the greatest danger from an asteroid strike is from the ones we haven't yet found. Of asteroids larger than the one that struck Tunguska in 1908, we know of less than 1 percent of them. And as David Morrison points out, we can't protect ourselves from the unknown asteroids (or make use of them either). The B612 Foundation Sentinel Space Telescope is going to work on finding and tracking these asteroids."
And here are some comments from Apollo 9 astronaut Rusty Schweickart, who has played a key role in raising awareness about the threats and opportunities presented by near-Earth objects. It was Schweickart who warned in the wake of Hurricane Katrina that asteroids like Apophis could spark a much more devastating "cosmic Katrina":
"I'm hoping that you don’t follow the bad (surprisingly wide) precedent of stating that [the risk from] Apophis has been eliminated. Please look on the JPL risk page and especially the more detailed info and note that 1) The 2036 impact possibility is, while significantly reduced, still possible, and 2) that the 2068 impact possibility is now elevated ... to a level that exceeds what the 2036 impact was prior to this apparition.
"There’s certainly good news re the 2036 impact decreasing in probability ... but frankly it was 1 in 234,000 prior to the new observations ... not exactly an impact probability to worry one. (There are many NEOs with higher impact probability ... but no one pays attention to them ... they aren't the 'poster child' that Apophis is.) My personal reaction was one of surprise that the new 2036 impact was not zero!
"But/And ... there are more radar observations to integrate in ... as well as optical tracking both now and for the next several years. Apophis isn't going away ... the impact possibilities are simply shifting around a bit with refinement of the tracking data. 2036 is now less probable; 2068 is now more probable (but still very low).
"Until JPL and the other guys get more data (enough to really define the Yarkovsky effect), we really won’t be able to get definitive data for longer time scales that we can rely on."
JPL's Giorgini said the risk assessment that Schweickart mentioned won't be full updated until after Goldstone and Arecibo finish their observational campaign in mid-February — so there may still be a non-zero risk listed until then. But Giorgini is confident that the 2036 risk will disappear when all the observations are factored in. (As of this writing, the estimated risk of collision is listed at 1 chance out of 10,989,000.) But you're right, Rusty: In order to eliminate the risk completely, astronomers will have to get more data about Apophis' physical characteristics. And then there are all those other unknown killer asteroids that might be out to get us...
Anyone who's looked at the "Seven Minutes of Terror" trailer for next month's Mars landing might have wondered whether the planners behind NASA's $2.5 billion Mars Science Laboratory mission really knew what they were doing — and although the planners insist they're confident, they also say they're nervous.
"There's not a whole lot we can do about it at this point, except just be nervous," said Dave Beaty, chief scientist for the Mars Exploration Directorate at NASA's Jet Propulsion Laboratory.
You can test the mood for yourself by tuning in our "Virtually Speaking Science" talk show at 9 p.m. ET tonight, via BlogTalkRadio or the Second Life virtual world. Beaty and I will be talking about the buildup to the Aug. 5 landing, and taking your questions through Second Life, Twitter (use the hashtag #askvs) and the phone lines. If you can't make it, don't worry: You'll be able to listen to the hourlong podcast via BlogTalkRadio's archive or iTunes.
Experts at NASA's Jet Propulsion Laboratory share the challenges of the Curiosity rover's landing plan.
Falling into place All the pieces are falling into place for the Mars Science Laboratory's landing sequence, aimed at putting the subcompact car-sized Curiosity rover down within Gale Crater. On Tuesday, NASA maneuvered its Mars Odyssey orbiter into the correct trajectory to pass over the landing site just in time to pick up telemetry from the probe.
The MSL spacecraft is currently within 2.2 million miles (3.6 million kilometers) of Mars and closing in fast. The big nail-biter is scheduled for just after 10 p.m. PT on Aug. 5 (1 a.m. ET Aug. 6), when the spacecraft is supposed to blaze through Mars' atmosphere, spring a parachute, pop off its heat shield and let loose a rocket-powered sky crane platform that will hover about 66 feet (20 meters) above the Martian surface and lower Curiosity on cables. Then the cables will cut loose and the sky crane will fly itself out of the way, leaving Curiosity to get down to business.
Dave Beaty is chief scientist for the Mars Exploration Directorate at NASA's Jet Propulsion Laboratory.
"I've met with the engineers," Beaty told me. "I've seen their presentations, and they can be very convincing. But you have to hold your breath a little bit and trust that they know what they're doing."
This multibillion-dollar mission depends on everything working right — and there's even more at stake than just the mission. If next month's landing fails, that could spark even more questions about the future of NASA's troubled Mars exploration effort. The failures of Mars Climate Orbiter and Mars Polar Lander in 1999 led to years of rethinking and retrenchment, and the soul-searching would probably go far deeper in this current age of tightened budgets and downscaled ambitions.
On the other hand, a successful landing would set a sunny tone for what's likely to be years of exploration by the most capable interplanetary robot ever created. During tonight's talk show, Beaty will probably be a lot more willing to talk about that type of scenario, just as he was when I interviewed him on Monday. Check out this edited transcript, and bring your follow-up questions to "Virtually Speaking Science" at 9 p.m. ET.
Cosmic Log: So, there's less than two weeks before the big Mars landing — what's going on there at JPL?
Dave Beaty: We're getting very nervous. There's not a whole lot we can do about it at this point, except just be nervous. But this is a significant thing. It's one of these points in history that may change the trajectory of things that happen afterward, whether we end up with a successful landing or an unsuccessful landing.
Q: What do you see as the outcome for failure, and the outcome for failure? What would that mean to the Mars exploration program?
A: Well, just having a successful landing, by itself, is of course huge good news. It enables the scientific return from the mission to happen, which will play out over the next Mars year — that's two Earth years, more or less. Once the rover lands, it has to raise its antenna, do some checkouts, get moving, and then drive over to this mountain that has the stratigraphy we're interested in.
It's sort of like the Grand Canyon way of looking at rock. You get this beautiful exposure of stratigraphy because of the erosion of this mountain. We want to climb up the side of the mountain and check the layering, like John Wesley Powell did just after the Civil War when he went one-arming up and down the Grand Canyon. That was one of the great geological expeditions of all time, as far as I'm concerned.
The site we want to look at is great. It's a little hard to predict exactly what we're going to see inside those rocks if we end up on the success pathway. We know what we're looking for: What are the rocks? What is the nature of the layering? Are there signals that the layers were "habitable" — i.e., had the potential for a life form to have lived there, had a life form been present. If there's a positive outcome on that, then we would definitely want to send another mission — either back to the same place, to check out whether there's any sign of something actually there; or potentially to another place that has the same kind of layering, but some other kind of characteristic.
Here on Earth, one of the big issues we face is that the preservation of the signs of life is very uneven. We know that there's life everywhere on Earth, right? And it's been here in sort of the form that we see it when we look out our windows, back to the time of the Cambrian, which is 600 million years ago. But if you look at the sedimentary rocks, they don't all contain fossils, they don't all contain pollen. You've got to look carefully to understand what has happened to the rock since its formation, and whether it would have included the signs of life, and whether those signs would have survived through all the subsequent things that happened to the rock.
It's not a guarantee that we would go back to exactly the same place, but we would certainly want to go back somewhere if we received this encouragement.
Q: And the implications of failure?
A: If it's a bad landing, the question would be, what is the reason why? In my experience, the public and Congress and all the people surrounding us would be accepting of a failure that was just a bad weather day, or if you land sideways on a rock, or some other sort of bad luck that happens because of what Mars has done to us. They tend to be less forgiving of a mistake made by a human being here on Earth. So, those are two very different kinds of scenarios. Just the fact of a bad day doesn't tell you enough to know what the implication might be.
Seven minutes of terror is what NASA is calling the waiting period to find out whether the Curiosity rover has survived what could be the trickiest landing ever attempted. NBC's Tom Costello reports.
Q: A lot of people wonder about how the sky crane is going to work, or whether the heat shield will work properly — the "seven minutes of terror." Is that what you have in mind? Everything that could be done has been done, of course, but if something goes wrong, I suspect people will want to focus on the process for doing something that's never been done before.
A: Almost everything we do at Mars has never been done before. That's what makes this exciting from the point of view of the engineers. They're here to do the impossible. That sky crane landing has some very powerful advantages, if it works. I've met with the engineers, I've seen their presentations, and they can be very convincing. But you have to hold your breath a little bit and trust that they know what they're doing.
Q: If everything works nominally, will we see the sky crane become the main method for getting large payloads down to the surface of Mars?
A: I absolutely think so. For the robotic exploration missions, the bigger question is, do we want the payloads to keep getting bigger? We know for sure that the pathway to eventual human missions has to involve bigger and bigger payloads, because the humans and all their support systems are heavy. This particular landing system will land a payload that's bigger than can be landed with airbags. The airbag would not survive. So it is heading in the direction that we need to follow if we believe in eventual human exploration. Whether the next robotic mission needs to be the same size as MSL — that's an interesting question. We may want to get it smaller, in part to bring the cost down.
Q: What's your role going to be on the night of the landing?
A: I just got my assignment. I will be at Beckman Auditorium at Caltech, with an audience of 1,136 people, which is the auditorium's capacity. I'll be standing in front of them with the NASA feed on the screen behind me, and my instructions are to narrate it like a tennis match. You can interject a little bit of commentary, but you don't want to detract from the main show, which is what's on the screen.
Q: So when will you know if the landing's been successful?
A: The landing itself is at 10:32 p.m. Pacific time, and we've placed both orbiters [Mars Odyssey and Mars Reconnaissance Orbiter] so they will be in position to watch the descent as it comes down. By 10:32 or 10:33, they should have the data to know whether the landing was successful. They may get an ambiguous answer and not know for sure whether it was successful or not successful. That may take a little while longer to sort that out. It's hard to end up with a for-sure crash scenario quickly, because the signals are likely to be less than obvious. But if it's successful, we'll know very quickly.