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Monday, November 18, 2013

Plutonium at the Bay of Rainbows


The Bay of Rainbows (Sinus Iridum). Image Source: NASA via Space.com.

Next month, China will launch an unmanned lander mission to the moon, which, if successful, will be the first non-crash landing on the moon since Apollo 17's 1972-1973 manned mission and Russia's unmanned Luna missions from the mid-1970s. Although the International Space Station has contributed invaluably to our knowledge of how to live in outer space, there is a sense now (not least with mythical movies like Apollo 18 - see my posts on that film, here and here) America got sidetracked when she abandoned the moon. Of course that myopic view also excludes NASA's great accomplishments in the exploration of Mars over the past twenty years.
Apollo 17 mission insignia. Image Source: Wiki.

Nevertheless, it was an American flag that was first planted on the moon during the Apollo 11 mission in 1969. Apollo 17 was also the most recent, and sixth, manned mission to the moon. For all Russia's contributions, humans had walked on the moon, and the moon was American! For over a generation, that claim has rested on laurels which lay neglected and undisturbed.

No longer. The moon is a fickle mistress. NASA's proprietary and imperial claim is slipping away. Why America did not return to the moon was not just about money or engineering. It was about politics and public will. Before 9/11 - I will never forget this - George W. Bush stated that his historic intention for his presidency - his hoped-for mark to be made - was to put an American on Mars. He planned to plough all of America's considerable extra pre-recession resources into space exploration.

Sister Moon (1987) © Sting / A&M. Video Source: Youtube.

The ugly destiny that intervened on September 11th - followed by the Space Shuttle Columbia disaster in 2003 - saw America hopelessly sidetracked way beyond the International Space Station's benign distraction. For all the criticism leveled at George W. Bush, I prefer to think of him as a president who came to the office nursing his inner James Tiberius Kirk, not his inner Michael Myers. Was this a president who wanted to return America to the final frontier, and who was side-swiped by another imperial fate?

Whatever the president's intentions, the country's interstellar Manifest Destiny was re-routed, and returned firmly to the most depressing of earthly concerns. An American Mars, originating from the turn of the Millennium, might have (if you believe Kim Stanley Robinson, would have) ended in tears. But we'll never know.

The only conspiracy theory about the so-called moon landing hoax that I ever found believable was that it was a Russian rumour, a lie spread to undermine Americans' confidence in their country and its achievements. That the insidious hoax story is believed and spread by so many gullible Americans online (those misguided armchair revolutionaries who relentlessly ruin their revolution's purity through the constant pursuit of it) may well be a quiet Russian propaganda victory. If so, it is a victory not just of media manipulation, but of competing mentalities; because no country on this planet knows better how to spin gold out of the dross of depression than Russia does.

Now, NASA is a pitiable shadow of her former self. That doesn't come about because of Congress, or Obama, or the recession and funding cuts. It's about a people discarding a cherished dream, a diminished American public belief in a grand enterprise. NASA's current position is an extension of the recession, another loss of confidence, a loss in belief in the currency of the country. But the currency of the USA was never the American Dollar. It was dreams, ideals, beliefs.

"The Chang'e 3 lunar lander and moon rover is part of the second phase of China's three-step robotic lunar exploration program." Image Source: Beijing Institute of Spacecraft System Engineering via Space.com.

And so, the Chinese launch is scheduled for 1 December 2013; The Space Review reports that the Chinese are using plutonium as a heat source, and they are sending their lander to the moon's Bay of Rainbows:
Next month, if all goes according to plan, China will launch a spacecraft to the Moon. Their goal is to land the Chang’e-3 spacecraft on the Moon’s Bay of Rainbows and deploy a rover, and if the Chinese succeed it will be the first lunar soft landing since the mid-1970s, and the first rover on the Moon since 1973. It will also represent a significant technological achievement, and provide valuable scientific data. 

So far China has released a fair amount of information about Chang’e-3, including numerous photos of the lander and rover. The lander is big: 2.5 meters on a side, and 4.76 meters from one landing gear to the opposite one. Fully fueled its mass is 3800 kilograms and it is capable of delivering a 1700-kilogram payload to the Moon’s surface. It is not really big enough to carry humans, but it can carry much more payload than the relatively small rover it is hauling on this mission.

There are still many unanswered questions about the mission. One of the more interesting ones is how the Chinese plan on keeping the lander and rover warm during the long lunar night. According to a paper by Sun ZeZhou, Jia Yan, and Zhang He in Science China (“Technological advancements and promotion roles of Chang’e-3 lunar probe mission”), the lander and rover are equipped with radioisotope heating units, or RHUs, using a two-phase heat transfer system.
The article does not indicate what isotope the Chinese are using in the RHUs. According to an article by Yang Jian on Xinhua, the rover will be “powered” by plutonium-238 (Pu-238.) Another article by Craig Covault in Aerospace America claims that both the lander and rover will be powered by Pu-238, but also have solar panels. Thus, none of the sources that discuss the use of radioisotopes are consistent with each other, but the Science China paper was written by engineers responsible for developing the spacecraft and seems fairly clear that the lander and rover are powered by solar panels, and have RHUs only to keep them warm during the cold lunar night—in other words, the RHUs are heaters but not power sources. ...

Pu-238 does not occur naturally. It has to be manufactured using a laborious process. It is not the same kind of plutonium used in nuclear weapons, which is Pu-239. The manufacture of weapons-grade Pu-239 produces a silvery-gray metal known as neptunium. If slugs of neptunium are suspended next to a specially designed reactor core, some of the neptunium is converted to Pu-238. The slugs are then processed and the Pu-238 is removed and refined and concentrated. This is a time-consuming and complicated process—any process to produce isotopes produces tiny amounts at a time—and it requires dedicated specialized equipment. The United States still has that equipment. Russia may still have it, although the equipment has probably fallen into disrepair. 

So where did China get the Pu-238? They probably manufactured it themselves. And that’s no minor accomplishment.

Image Source: China.org

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