North Korea announced on April 2 that it would restart its nuclear facilities, including its 5-megawatt-electric (5-MWe) nuclear reactor in Yongbyon, north of the capital, which had been disabled and mothballed since an agreement in October 2007.

Pronouncements from Pyongyang during the past few weeks have been ominous, including threatening the United States and South Korea with pre-emptive nuclear attacks. On April 2, 2013, a spokesman for North Korea’s General Department of Atomic Energy told the Korean Central News Agency that at the March 2013 plenary meeting of the Central Committee of the Workers' Party of Korea: “A new strategic line was laid down on simultaneously pushing forward economic construction and the building of nuclear armed forces.”

The pronouncement continued: “The field of atomic energy is faced with heavy tasks for making a positive contribution to solving the acute shortage of electricity by developing the self-reliant nuclear power industry and for bolstering up the nuclear armed force both in quality and quantity until the world is denuclearized.”

We ask Stanford Professor Siegfried S. Hecker – former CISAC co-director and now a senior fellow at CISAC and the Freeman Spogli Institute – to weigh in. Hecker has been invited seven times to North Korea and he made international headlines when he returned from his last trip in November 2010 and announced the isolated North Asia nation had built a modern uranium enrichment facility.

Q: How concerned should we be about North Korea’s announcement that it will restart all its nuclear facilities? Does this fundamentally change the threat imposed by Pyongyang?

Hecker: It does not immediately change the threat, but it really complicates the long-term picture. This announcement indicates that North Korea’s nuclear arsenal is severely limited by a lack of fissile materials, plutonium or highly enriched uranium (HEU) to fuel its bombs. Despite its recent threats, North Korea does not yet have much of a nuclear arsenal because it lacks fissile materials and has limited nuclear testing experience. In the long term, it’s important to keep it that way; otherwise North Korea will pose a much more serious threat. So, it is important that they don’t produce more fissile materials and don’t conduct more nuclear tests. The Kim Jong Un regime has already threatened to conduct more tests and with this announcement they are telling the world that they are going to make more bomb fuel. I should add that they also need more bomb fuel to conduct more nuclear tests.

Q: What do you make of the previous threats to launch an all-out nuclear war against the United States and South Korea? Does North Korea have the technical means to do so?

Hecker: I don’t believe North Korea has the capacity to attack the United States with nuclear weapons mounted on missiles, and won’t for many years. Its ability to target and strike South Korea is also very limited. And even if Pyongyang had the technical means, why would the regime want to launch a nuclear attack when it fully knows that any use of nuclear weapons would result in a devastating military response and would spell the end of the regime?  Nevertheless, this is an uneasy situation with a potential for miscalculations from a young and untested leader.  

Hecker spoke about North Korea with Christiane Amanpour on CNN, April 2, 2013. 

Q: The Kim Jong Un regime has reiterated and apparently put into law that North Korea will not give up its nuclear arsenal. Does the current announcement really make things that much worse?

Hecker: I have previously stated that North Korea has the bomb, but not yet much of an arsenal. It has been clear for some time that North Korea will not give up its nuclear weapons, so what we should have focused on is to make sure things don’t get worse. I have stated it as the three No’s: no more bombs, no better bombs and no export. We don’t know much about North Korea’s nuclear exports, but that potential is a serious concern. Pyongyang took a step toward better bombs with its successful Feb. 12 nuclear test, although it still has little test experience. The current announcement demonstrates that they will now redouble efforts to get more bombs by increasing their capacity to make plutonium and HEU. It won’t happen quickly because these are time-consuming efforts – but it bodes ill for the future.

Q: Let’s look at the technical issues of the latest announcement. What do you think Pyongyang means by “readjusting and restarting all the nuclear facilities in Yongbyon? 

Hecker: The restarting is easy to decipher: They plan to take the 5-MWe gas-graphite plutonium production reactor out of mothballs and bring the plutonium reprocessing facility back into operation. The “readjusting” comment is less clear. It may mean that they will reconfigure the uranium enrichment facility they showed to John Lewis, Bob Carlin and me in 2010 from making low enriched uranium (LEU at 3 to 5 percent for reactor fuel) to making highly enriched uranium (HEU at 90 percent for bomb fuel). 

Q: What did you learn about the 5-MWe reactor during your November 2010 visit to Yongbyon? Will they really be able to restart it?

Hecker: Lewis, Carlin and I were shown the beginning of the construction of the small experimental light-water reactor. The containment structure was just going up. I pointed to the 5-MWe reactor right next door and asked the chief engineer of the reactor, "What about the 5-MWe gas-graphite reactor?" He replied: “We have it in standby mode.” I told him that people in the West claim it is beyond hope to restart. He chuckled and said, "Yes, I know, that's what they also said in 2003, and they were wrong then as well." The reactor had been mothballed since 1994 as part of the Agreed Framework. The North Koreans restarted it in 2003 without much of a problem and ran two more campaigns to make plutonium.

Q: Is there any indication that they actually have an HEU bomb?

Hecker: We really don’t know. To the best of our knowledge, the first two nuclear tests in 2006 and 2009 used plutonium for the bomb fuel. We do not know what was used in the most recent test on Feb. 12. It could have been either HEU or plutonium. It would not surprise me if they have been pursuing both paths to the bomb; that’s what the United States did during the Manhattan Project.

Q: Will we know when they restart the reactor?

Hecker: Yes, using satellite imagery we should be able to see the steam plume from the cooling tower as soon as they rebuild and restart it.

Q: Didn’t North Korea also have a 50-MWe reactor under construction? What happened to that?

Hecker: As part of the Agreed Framework in 1994, North Korea agreed to freeze the operation of the 5-MWe reactor and the construction of its bigger cousins, a 50-MWe reactor in Yongbyon and a 200-MWe reactor in Taecheon. We saw the 50-MWe reactor in 2004 and were told that they were evaluating what it would take to get it restarted. During later visits we were told and saw for ourselves that it was not salvageable. We were told the same was true for the Taecheon reactor. The North Koreans had been willing to trade these two gas-graphite reactors for the KEDO light-water reactors that the United States, South Korea and Japan had agreed to build at Sinpo. However, the deal fell apart when the Agreed Framework was terminated in 2003.

Q: What would it take to restart the 5-MWe reactor? And how much plutonium could it make?

Hecker: The reactor has been in standby since July 2007. In June 2008, as a good-will gesture to Washington (and a reputed fee of $2.5 million from the U.S., according to North Korean officials), Pyongyang blew up the cooling tower. In addition, based on our previous visits, we concluded that they also needed to do additional work to prepare the fresh 8,000 fuel rods required to restart the reactor. If they restart the reactor, which I estimate will take them at least six months, they can produce about 6 kilograms of plutonium (roughly one bomb’s worth) per year. What they may do is to run the reactor for two to four years, withdraw the spent fuel, let it cool for six months to a year, and then reprocess the fuel to extract the plutonium. In other words, from the time they restart the reactor, it would take roughly three to four years before they could harvest another 12 kilograms of plutonium. The bottom line is that this is a slow process.

Q: How difficult would it be for North Korea to adjust its centrifuge facility to make HEU? And, if they did, how much HEU can they make?

Hecker: Not very difficult. It just requires reconfiguration of the various centrifuge cascades and adjusting operational procedures. That could be done very rapidly. They most likely had everything prepared in case they ever wanted to make this move. If they reconfigure, then based on our estimates, they could make roughly 40 kilograms of HEU annually in that facility – enough for one or two HEU bombs a year.

Q: How big is North Korea’s plutonium stockpile?

Hecker: After our 2010 visit, I estimated that they had 24 to 42 kilograms of plutonium, roughly enough for four to eight bombs. If the 2013 nuclear test used plutonium, then they may have 5 or 6 kilograms less now. Because they have so little plutonium, I believed that they might have turned to uranium enrichment to develop the HEU path to the bomb as an alternative.

Q: Could you explain what you see as North Korea's capabilities in regard to putting nuclear warheads on short-, medium-, and long-range missiles?

North Korea has conducted only three nuclear tests. The 2006 test was partially successful; the 2009 and 2013 tests likely were fully successful. With so few tests, the North Korean ability to miniaturize nuclear warheads to fit on its missiles is severely limited. After the first two tests, I did not believe North Korea had sufficient test experience to miniaturize a nuclear warhead to fit on any of its missiles. I believed the nuclear devices tested were likely primitive -- on the order of the Nagasaki device, which weighed roughly 5,000 kilograms. Official North Korea news outlets implied they were more advanced, and some Western analysts agreed. I stated that they needed additional nuclear tests to miniaturize.

Q: After the test in February, Pyongyang announced that it had successfully tested a smaller and lighter nuclear device. North Korean news media also specifically stated that this was unlike the first two, confirming that the earlier tests involved primitive devices. The Kim Jong Un regime followed the claim of having smaller and lighter warheads with threats of launching nuclear-tipped missiles against the United States and South Korea.

My colleague, CISAC Affiliate Nick Hansen, and I do not believe that the North Koreans have the capability to miniaturize a warhead to fit on a long-range missile that can reach the United States because the weight and size limits are prohibitive for them. They have insufficient nuclear test experience. Although last December they were able to launch a satellite into space, it is much more difficult to develop a warhead, fit it into a reentry body, and have it survive the enormous mechanical and thermal stresses of reentry on its way to a target. In April 2012, Pyongyang paraded a road-mobile long-range missile we call the KN-08. It may have been designed to reach as far as Alaska and the US West Coast, but to our knowledge it has never been test fired. There is some evidence that the first-stage engine may have been tested last year and early this year at the Sohae (Tongchang) launch site on North Korea's West Coast. North Korea would need a lot more missile tests as well as more nuclear tests to present a serious long-range threat.

He broke the news to the world that North Korea had built a modern uranium enrichment plant. He’s helped the Russians secure their vast stockpile of ex-Soviet fissile materials. And Stanford students routinely rank him as one of their favorite professors. 

Siegfried Hecker, one of he world’s top nuclear scientists and co-teacher of the popular course, “Technology and National Security,” has completed his five-year tenure as co-director of the Center for International Security and Cooperation (CISAC).

Though Hecker is stepping down from the leadership role, he’s not walking away.

“He’s not going anywhere,” emphasized his successor, Stanford microbiologist and biosecurity specialist, David Relman, as he opened a seminar in Hecker’s honor on Feb. 25. The panel discussion, “Three Hard Cases: Iran, North Korea and Pakistan” featured Scott Sagan, Malfrid Braut-Hegghammer, Abbas Milani, Robert Carlin and Feroz Khan.

“He’ll be back this summer with his infectious energy and unswerving dedication for which he is so well known,” Relman said.

Hecker, 69, is taking a sabbatical in New Mexico – where he was director of the Los Alamos National Laboratory for more than a decade before coming to Stanford – and then at the Vienna Center for Disarmament and Non-Proliferation, run by the Monterey Institute of International Studies. He’ll continue work on his book about his historic efforts to foster collaboration between U.S.-Russian nuclear labs and do some travel to meet his nonproliferation counterparts in other parts of the world.

“CISAC is part of my heart and soul now,” Hecker told a reception in his honor after the seminar. “Los Alamos was in my blood and bones. Today, Stanford is part of that too.”

Hecker will return to CISAC this summer to resume his writing and research projects as a senior fellow at CISAC and its umbrella, the Freeman Spogli Institute for International Studies (FSI). He’ll head back to the classroom as well.

“What I found out is that teaching is so much harder than just giving a lecture, because you really have to pay attention to what the students have actually absorbed,” Hecker said. “You need to be able to communicate with each and every one of them.”

Among the many national honors that Hecker has received over the years, the one he treasures most is the 2010 Eugene L. Grant Award for Excellence in Undergraduate Teaching, an honor voted on by the students.

Lauren Cipriano, a Ph.D. candidate in Mechanical Science and Engineering, has been Hecker’s teaching assistant for four years. She noted his class co-taught with former Secretary of Defense William J. Perry – also a senior FSI fellow and CISAC faculty member – is routinely attended by hundreds of students and rated among the best.

“He shares his own stories of how developing personal relationships with Russian nuclear scientists in the wake of the Cold War helped overcome diplomatic challenges, and how he continues those efforts today in Russia and North Korea to make the world a safer place,” she said in her reception toast. “Sig also has a scary ability to predict the future. Several times our policy paper assignments have nearly come true.”

One of those dramatic examples unfolded in 2010. While the students were writing a paper about how they would respond to the discovery that North Korea had established a uranium enrichment facility, Sig was traveling to Pyongyang.

“Our students were some of the first to hear the stunning news of the uranium enrichment facilities the North Koreans revealed to him on his trip,” she said. “The students couldn’t have been more excited to feel like insiders in the national security policy arena.”

Hecker said he is particularly proud of the bright young scientists who have come through as CISAC fellows during his tenure.

“I think we’ve been able to build a really strong science component to support CISAC’s mission of building a safer world,” Hecker said. “We’ve been able to attract a lot of very good young scientists and then send them on to good careers from here.”

He said that working with these pre- and postdoctoral fellows and visiting faculty and scholars from the life sciences and political sciences “has helped me to better understand how important it is to bring the technical and social sciences together when looking at problems of international security.”

Hecker, who moved to the United States with his family from Austria when he was a boy, received his Ph.D. in metallurgy from Case Western Reserve University and began his professional career as a senior research metallurgist with the General Motors Research Laboratories in 1970. He joined the Los Alamos National Laboratory in 1973, became its director in 1986 and served for more than a decade.

Hecker came to CISAC in 2005 as a visiting professor, having been recruited by Sagan, who was then the social science co-director of CISAC.

“Sig first became involved with CISAC when he was still at Los Alamos, through participating in our Track II nuclear diplomacy efforts with John Lewis in North Korea and with me in a Five Nations project meeting in Thailand,” recalled Sagan. The Five Nations Project on Asian Regional Security and Economic Development focused on new challenges to nuclear nonproliferation by the U.S., China, Russia, India and Pakistan.

“I first broached the possibility of his coming to Stanford as a visiting professor when he and I were in the back seat of a taxi in Bangkok after giving a joint lecture at the Royal Thai Military Academy,” in July 2004, Sagan said. “He has been a stellar leader and now that he is stepping down from administrative responsibilities, he will have even more time to be involved in CISAC’s nuclear nonproliferation activities around the globe."

CISAC co-director, Tino Cuéllar, called himself a “charter member of the national federation of the Sig Hecker fan club.”

“In his eventful, five-year tenure, Sig has been an extraordinary leader,” Cuéllar said. “He’s been a visionary about its future, an endlessly enthusiastic supporter of its varied missions and a role model of excellence combined with the collegiality that CISAC prizes so dearly.

North Korea conducted an underground nuclear test on Tuesday, prompting President Barack Obama to call the detonation of a miniature nuclear device a “highly provocative act” that threatens U.S. security and international peace. It is the third nuclear test by Pyongyang since 2006 and is escalating concern that the isolated Stalinist state is now closer to building a bomb small enough to be fitted on a missile capable of striking the United States and its allies. The test was conducted hours before Obama’s annual State of the Union speech.

North Korea’s official Korean Central News Agency said the test was conducted, “in a safe and perfect way … with the use of a smaller and light A-bomb, unlike the previous ones, yet with great explosive power.” The statement said the nuclear device did not impose “any negative impact” on the environment.

North Korea said the atomic test was merely its “first response” to what it called U.S. threats and said there would be unspecified “second and third measures of greater intensity” if the United States remains hostile to the North. Washington had led the call for more U.N. sanctions against Pyongyang after the North launched its first rocket and put a satellite into obit in December. While the North said the launch was for its civilian space program, the Obama administration believes it was part of a covert program to develop ballistic missiles that can carry nuclear warheads.

We ask two Stanford experts on North Korea to weigh in: David Straub, the associate director of the Korean Studies Program at the Walter H. Shorenstein Asia-Pacific Research Center (APARC), and Nick Hansen, an affiliate of the Center for International Security and Cooperation who is an expert in foreign weapons systems.   

Q. Why conduct the test now?

Straub: Since the two previous North Korean nuclear tests took place on American holidays and the North Korean themselves have announced that their moves are "targeted" at the United States, many observers have concluded that the this test was especially timed to coincide with President Obama's State of the Union address. It is also possible that, as others have speculated, the North Koreans also took into account that Feb. 16 is the birthday of North Korean leader Kim Jong Un's father, Kim Jong Il, the man who is said to have instructed North Koreans to proceed with the nuclear weapons and missile programs. Others have speculated that the North Korean leadership wanted to test the device before the Feb. 25 transition in South Korea from the current president Lee Myung-bak, to the president-elect, Park Geun-hye. The timing could be intended to punish Lee, whom the North Koreans say they despise, while, the argument goes, making it a little easier for Park to reach out to the North before her inauguration.

Q. What message is North Korea’s young and relatively new president, Kim Jong Un, trying to send to the world with this test?

Hansen: Kim seems to be saying: I’m going to do what I say I’m going to do – and nobody is going to dissuade me. The North said they were going to launch a satellite, and by God they did. They said they were going to touch off a nuclear test after that, and by God they did. Now we have to wait and see what’s next.

Straub:  The North Koreans themselves are saying that the test is a response to the military threat posed to it by the United States and to U.S.-led UN sanctions imposed on North Korea after its rocket test in December. The North Koreans have complex motivations for pursuing nuclear weapons. Many North Koreans may actually believe that having nuclear weapons will defend them against the United States. But the fact of the matter is that the United States and South Korea have never attacked North Korea over the decades, while the North Koreans have repeatedly attacked South Korean and American targets, most recently killing 50 South Koreans in 2010. North Korea's top leaders see nuclear weapons and missiles as a panacea. Fearful of opening up to the outside world because of the lies they have told their people, Pyongyang wants to believe that it will eventually maneuver the United States and the international community as a whole into accepting its possession of nuclear weapons and forcing the removal of sanctions against it. That won't happen, but even if it did, it would not resolve Pyongyang's basic problems, which stem from the totalitarian nature and history of its regime.

Q. What concerns you most in the wake of this test?

Hansen:  The thing I’m worried about now is that they also said they’re going to launch more satellites and long-range missiles. They displayed one in the military parade of 2010, an intermediate-range missile that can probably go 2,000 miles. When you think about that, 2,000 miles, or maybe a little bit longer, it puts just about every U.S. base in Asia under its threat, including Guam, Okinawa, Taiwan and everything in Japan. It’s a threat if they could put a warhead on it. The KN-08 is a bigger, three-stage rocket and is more of a threat, with the potential of hitting at least Alaska, Hawaii and maybe the U.S. West Coast. But remember, the North has tested neither.

Q. The test was in defiance of Pyongyang’s chief ally, Beijing, which had urged Kim not to risk confrontation and said the North would “pay a heavy price” if it proceeded with a test. How will China respond?

Straub: China is key in dealing with the North. China provides North Korea with most of its external support, including vital food and energy supplies. Chinese leaders are certainly not happy with their North Korean counterparts, as China would prefer peace and stability in the region, so it can focus on its own economic development. But Chinese leaders are fearful that putting a great deal of pressure on North Korea might result in chaos, with unpredictable and possibly very dangerous repercussions for China and the region. Thus, before North Korean nuclear and rocket tests, typically the Chinese press Pyongyang not to proceed. But immediately after a test, the Chinese begin to urge "all parties" to exercise restraint. In the United Nations, where China has a veto on the Security Council, it reluctantly agrees to the minimum condemnations of and sanctions against North Korea. After the dust settles, however, China doesn't seriously implement the sanctions. In fact, since North Korea conducted its first nuclear test in 2006, Chinese trade with North Korea has dramatically increased as a result of a PRC government decision to support North Korea. China may agree to a stronger resolution this time, but ultimately this pattern will almost certainly repeat itself.

Q. The North Koreans have said the test poses no risks to the environment or its people. Is this accurate?

Hansen: It takes a while for the particles that are released from the test to get released from the cracks in the rock and get into the atmosphere. My guess is that because of this very hard rock, they probably don’t have much of a radiation release problem. It probably will just seep through naturally and should not be of any danger. Engineers seem to have done a good job from a security and safety standpoint; the way the tunnels make right-handle turns and then there are the blast doors and piles of dirt to soak up any release.

North Korea Timeline

North Korea successfully launched a long-range rocket Wednesday, with the North American Aerospace Defense Command (NORAD) confirming Pyongyang had "deployed an object that appeared to achieve orbit." The defiant rocket launch has prompted worldwide consternation: Japan has called for an urgent meeting of the U.N. Security Council; the Obama administration called the launch a "highly provocative act that threatens regional security" and violates U.N. resolutions; and South Korea has raised its security threat level. 

Pyongyang insists it has a right to pursue a peaceful space program and that the rocket was armed with a communications satellite to help in that endeavor. But the U.S. and its allies worry the technology could lead to an intercontinental ballistic missile capable of carrying a nuclear warhead.  

We turn to three experts on North Korea for their views on the launch: David Straub, associate director of the Korean Studies Program at the Walter H. Shorenstein Asia-Pacific Research Center; Thomas Fingar, an international intelligence expert and the Oksenberg-Rohlen distinguished fellow at FSI; and Nick Hansen, a CISAC affiliate and expert in foreign weapons and imagery intelligence who writes for Jane’s Defense and 38North.org, a website for the U.S.-Korea Institute at SAIS.

Why is the global community surprised North Korea has successfully launched a rocket and apparently put a satellite into orbit? 

Straub: It shouldn't come as a surprise that North Korea has finally succeeded with its fifth test of a long-range rocket, which it's been trying to do since 1998. North Korea has pursued the development of nuclear weapons and missiles with great determination and intensity over many decades, because its leaders regard these as a panacea for problems actually originating in their own failed economic and political systems. 

Fearful that domestic reform would result in their overthrow, they continue to oppress and isolate their people while using military threats to intimidate other countries. Their aim is to remain in power and eventually prevail over their rival South Korea by forcing the lifting of international sanctions and being accepted as a nuclear weapons state. It is not irrational but it is very unrealistic. Most members of the international community, including the United States, will never accept this. North Korea is thus going ever deeper down a blind alley. 

The rocket technology is dangerously close to long-range missile technology and the United Nations Security Council has issued several resolutions and forbidden North Korea from conducting any further tests. 

Was there any significance to the Dec. 10-29 launch window? 

Straub: The media is full of speculation about why North Korea announced this particular window of dates, such as that it means to send a message to the Obama administration or to influence the upcoming South Korean presidential election on December 19.  My own guess is that it is keyed to the first anniversary Kim Jong Il’s death on December 17. 

But in the end, the most important question is why the North Koreans conducted the launch. It is fundamentally because they have a long-standing missile program to which they have devoted a great deal of resources. If the leadership had devoted those resources to taking care of its citizens, it could have bought enough food on the global market to prevent hunger, instead of calling on the international community for assistance.

The North Koreans typically pick the spring or summer to test their rockets. Why did it launch now amid constraining winter weather? 

Hansen: The timing is purely political. The reasons they prefer to launch in the spring and summer are, of course, better weather conditions and longer days to work on the pad. But the anniversary of the death of Kim Jong Il, the presidential elections in South Korea, beating the south to a satellite launch or putting the DPRK back in the international spotlight – these could all have driven the decision. 

North Korea may be following the same script they used for the (failed) April 12 Unha-3 launch. If they continued at the April pace, the rocket should have been completely stacked on the pad on Dec. 7 in order to be checked out on the 8^th and 9^th and be ready to launch on the 10^th, which was the first day of the launch window. This was a tight schedule with little room for technical problems or weather delays. (The North's Korean Central News Agency announced Dec. 10 that the launch window had been extended to the 29th, thus catching many North Korea observers off guard by the earlier launch.) 

Fingar: The timing is indeed outside the normal window of relatively better weather. Possible factors include commemoration of the anniversary of Kim Jong Il’s death; a ploy to capture the attention of new administrations in Washington, Beijing, Seoul, and Japan; and intent to buttress the North’s claim to having a nuclear deterrent by demonstrating that it can launch at any time of the year. There might also have been a simpler explanation, namely that DPRK engineers thought they had found and fixed the problem that caused the previous tests to fail and persuaded Kim Jong Un that there was no technical reason to delay.

What are the larger implications of North Korea’s actions and why do these rocket launches provoke such global condemnation? 

Fingar:  Perhaps the primary reason is that North Korea is widely perceived to be dangerous and more than a little bizarre. In other words, it is an easy target and symbolic embodiment of “worst case” fears about what a defiant and “irrational” country might do with its nuclear and missile capabilities. 

The world also sees that North Korea’s attempt to launch a satellite is interpreted, not unreasonably, as defiance of U.N. Security Council Resolution 1718, which demands that the DPRK not conduct any further nuclear test or launch a ballistic missile. Pyongyang argues that a rocket used for space launches is not a ballistic missile, and therefore is not proscribed by the U.N. resolution. 

Straub: North Korea has been developing medium- and long-range missiles for more than two decades, during which time it has repeatedly attacked South Korea and threatened the United States and other countries. It has also been working on its nuclear program and has already tested two nuclear devices. The fear is that North Korea is trying to miniaturize a nuclear device that could be used as a warhead on a long-range missile. 

In January 2011, former Defense Secretary Robert Gates voiced U.S. concern that North Korea was becoming a direct threat to it, and that Pyongyang could successfully develop intercontinental ballistic missile capability within five years.  

In South Korea, the launch is unlikely to have a major impact on the presidential election December 19. Conservative South Koreans regard North Korean behavior as stemming from the nature of its system, while progressives also blame the policies of the United States and conservative South Korean administrations for making North Korea feel insecure. Each side will simply interpret the launch from its longstanding perspective on North Korea.  

In Japan, where concern about North Korea runs deep both because of the nuclear and missile programs and North Korea's abduction of Japanese citizens, the launch will likely further strengthen the front-running conservatives in the Lower House election on December 16.

How is the international community responding to the launch? 

Straub: The United States has already signaled that it will seek even stronger international sanctions against North Korea. If China is unwilling to agree in the U.N. Security Council, the United States and its allies will pursue increased sanctions on their own. 

China has again been embarrassed by North Korea, but there is no indication that it will change its basic policy of supporting North Korea for fear it might collapse, creating an unpredictable situation on China's border. Even if China agrees to some increased sanctions against North Korea in the UN Security Council, its record of actually enforcing international sanctions is decidedly mixed. In any event, it has dramatically increased its economic support for and engagement with North Korea since that country's first test of a nuclear device in 20006. 

Is there anything more that Washington can do to prevent these provocations by the North aside from pushing the Six Party Talks and threats of greater sanctions? 

Fingar:  Probably not. Some argue that Pyongyang’s goal is to use the provocations to persuade the United States to negotiate directly with North Korea, but its conditions for doing so include U.S. acknowledgment – and acceptance – of the North’s self-proclaimed status as a nuclear weapon state. That is not likely to happen. I think the best course for the United States would be to avoid over-reacting and to focus attention on Pyongyang’s defiance of U.N. Security Council resolutions.

There is speculation that a third underground nuclear test will follow the rocket launch if it fails to put a satellite into orbit.

Hansen: I believe they will test regardless of the successful launch.  I have been following the nuclear test site at Punggye-ri all November. Details from a Nov. 19 image show that part of the dirt road into the complex from the valley is unusable, as three bridges have been washed out. Instead they have upgraded an old road that runs up the west side of the valley and enters the complex just in front of the new south tunnel. Imagery on Nov. 24 revealed some changes. The new road is still being used and there appears to be more vehicle tracks going to the support area. The most significant development is the probable clearing of snow at the entrance to the south tunnel. It also appears that the mine cart tracks are being reinstalled on the spoil pile to carry dirt out from the tunnel, but I can't be sure of that. 

See our interactive timeline on key events in North Korea here at Storify.com 

Hansen Interview with the Australia Broadcasting Corp. 

Hansen's Q&A with Popular Science with Popular Science on Why Launch Doesn't Spell Doom