Greetings, everyone.
Since their arrivals on opposite sides of Mars in January 2004 the twin rovers Spirit and Opportunity have performed above and beyond anyone's wildest dreams. After more than six years on the Martian surface, Spirit ceased transmitting in March of 2010, and while many attempts to re-establish contact were made, none were successful and the book on Spirit was officially closed in May of this year. Opportunity remains operational and has logged over 21 miles during its investigations. It is currently on its way to a feature called Cape York, where it will spend the winter in an area favorable for maintaining power to its solar batteries. Pretty impressive when you consider they were each given life expectancies of only 90 days. While I will make no predictions on how much longer Opportunity will last, if the combination of good engineering and favorable surface conditions continue it may very well live to see itself become obsolete.
About every two years the positions of Earth and Mars in their orbits allow for an optimal trajectory between the two planets. 30 days from now we will be in the next of these launch windows and the latest Mars rover will be sent on its way. Scheduled for liftoff at 9:25 AM CST, on Nov. 25th, (the day after Thanksgiving in the U.S, so you have no excuse not to watch on NASA TV or follow it online) the Mars Science Laboratory aboard the rover Curiosity will be the largest and most complex robot ever sent to the Martian surface. The size of a small SUV, the rover is packed with a multitude of scientific instruments that will study the atmosphere, the geology, the chemistry, and (potentially) the biochemistry in and around its intended landing site. Also, upping the awesomeness quotient by a factor of 100, it will be the first rover ever equipped with a frickin' laser defense system! Oh alright, the laser is technically part of the science payload, and its primary purpose will be to zap rocks and let other instruments examine the gases that are created or escape as a result, but if any little green men get too close...
Other fun Curiosity features include a 7-foot robotic arm for taking soil samples (the laboratory has tools to run many experiments on Martian dirt), tons of cameras, and a plutonium-238 power source, as solar panels would be unable to generate the energy necessary to run the rover's many systems. And for all you GD hippies now worried about radioactive contamination, keep in mind that with the thin atmosphere and lack of a magnetic field, the Martian surface is quite irradiated already, so Curiosity's impact will be negligible. The chosen landing site is the floor of the Gale Crater, a feature about 90 miles in diameter right along the Martian equator. Of the 30 sites that were considered, it rose to the top of the heap for having terrain that was both scientifically interesting and not too difficult for the rover to traverse. It would have been off limits to previous rovers, but improvements in our abilities to both build rovers and to land them precisely put the site on the table.
What will Curiosity find there? Who knows? And if we did know, what would be the point in going? So make it a point to watch the launch next month before you head off to the mall, though you might just want to make sure you pre-order the Curiosity replica (a must-have item for this holiday season, laser sadly not included) to put under the tree for junior just in case. Then, if all goes well, Curiosity will land in Gale Crater in August of 2012 to begin its 23 month (a full Martian year) primary mission. Those of you in need of more technical details can head over to the Mars Science Laboratory home page and geek out for a bit, and anyone with the Google Earth software can instantly call up the most up to date satellite images of the Martian surface and explore to their heart's content.
Tuesday, October 25, 2011
Saturday, October 22, 2011
Space Week 2011 #3: "50 Years of Human Spaceflight"
Greetings, everyone.
I know its been a while since the last one, and sadly writing/blogging is still something I do only as a hobby. Now it is only a coincidence that I am writing this on Oct. 22nd, the day after the latest failed prediction of the Rapture. Interestingly enough it also happens to be Darkness Day, the annual ritual at Surly Brewery where they sell their most excellent Russian imperial stout, called Darkness (I got mine, thank you very much). In a way I was almost hoping the Rapture would actually happen, since then the Tribulation, or, as most people call it, the Republican presidential nomination campaign, would have been blessedly over, but unfortunately it looks like we still have another year and few weeks of stupid bombardment to endure from the candidates. On to the topic at hand.
The first official Space Week was celebrated in 1999, and one year later I began my annual article series in honor of it. Space Week and its attendant activities are coordinated loosely by an organization called the World Space Week Association (WSWA), which works closely with the United Nations Committee on the Peaceful Use of Outer Space (COPUOS) to plan events and generate publicity. For the past several years the WSWA has declared a theme for Space Week, and for 2011 the theme was "50 Years of Human Spaceflight". This was highly appropriate since April 12, 2011 was the 50th anniversary of Yuri Gagarin's historic orbital flight aboard Vostok I. This day has long been celebrated in Russia, and some other former Soviet republics, as Cosmonauts' Day, and the commemorations there featured massive public ceremonies with all the pomp and circumstance that comes with them. While this may seem quaint to westerners we should remember that of the many legacies the Soviet Union left behind, the Soviet space program and its early achievements are one of the few of which Russia can be justly proud. Thus I am more than willing to let them whoop it up in Yuri's honor (having read a few things about him, I think he would heartily approve), but I also hope that one day April 12th will be celebrated worldwide on the scale it deserves.
Now that the hoopla has died down, though, we can look back on those 50 years with a more sober eye and ask ourselves "What have we really accomplished?" Regrettably, when I consider human spaceflight specifically I think my answer has to be not all that much, especially in comparison with how robotic exploration has fared. We started out pretty good, going from one man completing an orbit or two to sending crews of three to the Moon and back in barely eight years. But since then we have been stuck in low Earth orbit, with no nation or coalition of nations willing to make the investments necessary to truly push out into the Solar System. Why we have yet to make good on that early potential is a subject on which I can pontificate at length, but in a nutshell the reasons have more to do with the political (Cold War detente in the 70's turned the Space Race into a crawl) and economic (putting people in orbit is pretty damn expensive) environments than with any scientific barrier. Now, however, I think we might finally be ready to get going again, and the catalyst for this, oddly enough, is the retirement earlier this year of the Space Shuttle. Like many of you, I watched the final launch with a tear in my eye, nostalgic for the class of vehicles that for my entire lifetime has been the way NASA sent people into space. But look again at that last sentence. If the phrase "my entire lifetime" didn't jump out at you...well it should have.
I was born in 1977, so can no longer consider myself a spring chicken. Think for a minute how much computer technology has advanced from that time to today and you might be able to understand my disappointment. But hopefully that is water under the bridge. The shuttles were never meant to be around as long as they were, and we are capable of making something much better, so now that they are finally out of the way perhaps we will. This motivation coupled with two other factors are what I believe will help us get human exploration rolling again. Firstly, the last 30 years haven't been a complete waste, far from it. Thanks to the construction of the International Space Station (ISS) and the research now going on there we now know a lot more about how the human body might fare over the course of a long-term space voyage and the hazards from which it will need to be protected. Secondly, renewed and increased competition, both from other nations and from nascent private companies, will require NASA to up its game. The Chinese became the third nation to send their own people into space in 2003, and I will not be surprised if other emerging powers such as India or Brazil do so by the end of this decade. Also, the first private spaceport is now under construction in New Mexico, and later on we will take a closer look at how that industry is faring. For the next few years ISS crews will be using single-use Russian Soyuz capsules to get to and from orbit, but it is hoped that eventually private carriers could perform that function (though sadly you will be SOL if you bought a ticket to space from Pan-Am in 1968).
This handoff should then allow the folks at NASA to focus on the next big target, whether that be a return to the Moon, a near Earth asteroid, or even Mars. Anything that gets us beyond low Earth orbit on a consistent basis really, and the sooner the better. Though to expect advances in human spaceflight at a rate comparable to that in computing is pretty unrealistic, significant progress is possible when there is a clear goal and a reliable commitment of resources to make it happen. It will be expensive, certainly, but not beyond the pale, especially when many nations pool their funds and expertise, and investments of that type often pay off several times over as they spawn new technologies and create a more highly skilled workforce. I can think of nothing better to get this country out of the collective funk it has been in since late 2008, in both the economic and psychological sense, and look forward to the day when going into space will be as routine as air travel is currently.
I know its been a while since the last one, and sadly writing/blogging is still something I do only as a hobby. Now it is only a coincidence that I am writing this on Oct. 22nd, the day after the latest failed prediction of the Rapture. Interestingly enough it also happens to be Darkness Day, the annual ritual at Surly Brewery where they sell their most excellent Russian imperial stout, called Darkness (I got mine, thank you very much). In a way I was almost hoping the Rapture would actually happen, since then the Tribulation, or, as most people call it, the Republican presidential nomination campaign, would have been blessedly over, but unfortunately it looks like we still have another year and few weeks of stupid bombardment to endure from the candidates. On to the topic at hand.
The first official Space Week was celebrated in 1999, and one year later I began my annual article series in honor of it. Space Week and its attendant activities are coordinated loosely by an organization called the World Space Week Association (WSWA), which works closely with the United Nations Committee on the Peaceful Use of Outer Space (COPUOS) to plan events and generate publicity. For the past several years the WSWA has declared a theme for Space Week, and for 2011 the theme was "50 Years of Human Spaceflight". This was highly appropriate since April 12, 2011 was the 50th anniversary of Yuri Gagarin's historic orbital flight aboard Vostok I. This day has long been celebrated in Russia, and some other former Soviet republics, as Cosmonauts' Day, and the commemorations there featured massive public ceremonies with all the pomp and circumstance that comes with them. While this may seem quaint to westerners we should remember that of the many legacies the Soviet Union left behind, the Soviet space program and its early achievements are one of the few of which Russia can be justly proud. Thus I am more than willing to let them whoop it up in Yuri's honor (having read a few things about him, I think he would heartily approve), but I also hope that one day April 12th will be celebrated worldwide on the scale it deserves.
Now that the hoopla has died down, though, we can look back on those 50 years with a more sober eye and ask ourselves "What have we really accomplished?" Regrettably, when I consider human spaceflight specifically I think my answer has to be not all that much, especially in comparison with how robotic exploration has fared. We started out pretty good, going from one man completing an orbit or two to sending crews of three to the Moon and back in barely eight years. But since then we have been stuck in low Earth orbit, with no nation or coalition of nations willing to make the investments necessary to truly push out into the Solar System. Why we have yet to make good on that early potential is a subject on which I can pontificate at length, but in a nutshell the reasons have more to do with the political (Cold War detente in the 70's turned the Space Race into a crawl) and economic (putting people in orbit is pretty damn expensive) environments than with any scientific barrier. Now, however, I think we might finally be ready to get going again, and the catalyst for this, oddly enough, is the retirement earlier this year of the Space Shuttle. Like many of you, I watched the final launch with a tear in my eye, nostalgic for the class of vehicles that for my entire lifetime has been the way NASA sent people into space. But look again at that last sentence. If the phrase "my entire lifetime" didn't jump out at you...well it should have.
I was born in 1977, so can no longer consider myself a spring chicken. Think for a minute how much computer technology has advanced from that time to today and you might be able to understand my disappointment. But hopefully that is water under the bridge. The shuttles were never meant to be around as long as they were, and we are capable of making something much better, so now that they are finally out of the way perhaps we will. This motivation coupled with two other factors are what I believe will help us get human exploration rolling again. Firstly, the last 30 years haven't been a complete waste, far from it. Thanks to the construction of the International Space Station (ISS) and the research now going on there we now know a lot more about how the human body might fare over the course of a long-term space voyage and the hazards from which it will need to be protected. Secondly, renewed and increased competition, both from other nations and from nascent private companies, will require NASA to up its game. The Chinese became the third nation to send their own people into space in 2003, and I will not be surprised if other emerging powers such as India or Brazil do so by the end of this decade. Also, the first private spaceport is now under construction in New Mexico, and later on we will take a closer look at how that industry is faring. For the next few years ISS crews will be using single-use Russian Soyuz capsules to get to and from orbit, but it is hoped that eventually private carriers could perform that function (though sadly you will be SOL if you bought a ticket to space from Pan-Am in 1968).
This handoff should then allow the folks at NASA to focus on the next big target, whether that be a return to the Moon, a near Earth asteroid, or even Mars. Anything that gets us beyond low Earth orbit on a consistent basis really, and the sooner the better. Though to expect advances in human spaceflight at a rate comparable to that in computing is pretty unrealistic, significant progress is possible when there is a clear goal and a reliable commitment of resources to make it happen. It will be expensive, certainly, but not beyond the pale, especially when many nations pool their funds and expertise, and investments of that type often pay off several times over as they spawn new technologies and create a more highly skilled workforce. I can think of nothing better to get this country out of the collective funk it has been in since late 2008, in both the economic and psychological sense, and look forward to the day when going into space will be as routine as air travel is currently.
Wednesday, October 5, 2011
Space Week 2011 #2: "Hmm... That's Funny..." or "Dem Wacky Neutrinos"
Greetings, everyone.
Before jumping in to today's topic I'd like to point out that yesterday (Oct. 5th) was the birthday of one of my favorite living scientists and public intellectuals, Neil de Grasse Tyson. For those of you who don't know about him, he is currently the director of the Rose Center for Earth and Space at the American Museum of Natural History in New York City. He has held that position for several years, and over that time he has been one of the leading promoters of astronomy and planetary science to the general public as well as a likeable and articulate advocate for skepticism, critical thinking, and the scientific method. A couple of years ago I wrote that Tyson has in the estimation of many, myself included, come to occupy the place in our culture once filled by the late Carl Sagan, so it was fitting that earlier this year PBS announced that he is being tapped to host an updated version of Sagan's epic Cosmos series from 1980. I can't wait to see it.. Also, just so you know, both he and I would agree that the fact that his birthday happens to fall during Space Week is a simple coincidence. Uncanny certainly, but nothing more.
To start off today's discussion, I will refer to another person I greatly admire, Isaac Asimov. One of the towering science fiction writers of the 20th century, he also wrote a great deal of non-fiction (about 75% of everything he wrote, actually), and while I can't remember in what essay or article I read it, a quote of his seems very applicable to the recent news about neutrinos: "The most exciting phrase to hear in science, the only one that heralds new discoveries, is not 'Eureka!', but rather, 'Hmm... that’s funny...'."
While particle physics does not usually make headlines, a couple of weeks ago some jaw-dropping results from an experiment conducted by the Center for European Nuclear Research (CERN, the acronym for the laboratory's name in French) were made public and set the media on fire. Situated on the border between France and Switzerland, CERN had been sending a stream of neutrinos to an underground detector several hundred miles away in Italy. It was a pretty routine experiment to see how often one type of neutrino changed into another, but the folks in Italy noticed that the neutrinos were arriving just slightly a bit sooner than they should have been. Now neutrinos are thought to have no mass, and so like other massless particles (photons, principally) they travel at the speed of light. Thus their early arrival at the Italian detector, even if only by a few billionths of a second, appears to indicate that these neutrinos were traveling faster than light. Let that sink in for a minute. For more than a century one of the cornerstones of physics has been that nothing, yeah you heard that, nothing travels faster than light. The speed of light has been measured countless times, with ever growing degrees of precision and accuracy, and countless experiments have been conducted which without exception have confirmed this absolute speed limit. So if the CERN findings are confirmed it means we need to seriously rethink the two main theories that underpin our understanding of the Universe: Einstein's Relativity (both Special and General) and the Standard Model, which is the basis for quantum physics.
Lost in much of the ballyhoo that attended the CERN announcement was the fact that the potentially trailblazing results were not even related to what the original experiment was studying. So somewhere some scientist saying "Hmm...that's funny..." (or its French equivalent) is what started all of this. Now interestingly enough, it appears that this was not the first time neutrinos were observed breaking the light barrier. A few years ago a similar experiment that was conducted by Fermilab in Illinois produced the same eyebrow raising data when the neutrinos reached the detector at the Soudan Underground Mine facility in northern Minnesota (I've been there, it is a cool place, especially if you are a Battlestar Galactica fan). However those results were within the boundaries of experimental error, and so did not generate nearly as much publicity. But in the wake of the CERN announcement they are being revisited and laboratories around the world are racing to replicate the results. At the moment, the jury is still out on whether we will have to incorporate a new factor into the equations that describe reality, and it may be that some other team will find something that explains the discrepancy, but that is how science works. The CERN scientists combed over their results for six months, trying their best to account for anything that may have introduced an error or affected their calculations, and only after their searches turned up nothing did they reveal the findings to the rest of the scientific community. While nothing is sacred in science, you want to be pretty damn sure your observations are spot on when they could challenge a theory as rock-solid as Relativity, and if those observations can't be replicated then they will go down as a (for now) unexplained fluke and the theory will continue to be the standard.
Even though it has only been a couple of weeks since the announcement, many possible explanations for our supraluminal neutrinos have already been proposed. Some involve extra dimensions they take a shortcut through, others more prosaic things like flaws in equipment calibration, but all are highly technical so I'll spare the details. How will this all play out? I have no idea, but in order to truly make one's peace with the Universe you have to get comfortable with uncertainty, and not just in the narrow Heisenbergian sense. These are the sorts of situations that get science buffs like me extremely excited, because this is when science is at its best. For in science the news that something we thought was true might be wrong, even in only the most tiny of ways, is cause for exhilaration, not dread, and I can only imagine how the scientists actually working on the CERN results are feeling. We live in interesting times, folks, and have once again been reminded that the three most revolutionary words in the English language, or most any other for that matter, are "Hmm...that's funny..."
Before jumping in to today's topic I'd like to point out that yesterday (Oct. 5th) was the birthday of one of my favorite living scientists and public intellectuals, Neil de Grasse Tyson. For those of you who don't know about him, he is currently the director of the Rose Center for Earth and Space at the American Museum of Natural History in New York City. He has held that position for several years, and over that time he has been one of the leading promoters of astronomy and planetary science to the general public as well as a likeable and articulate advocate for skepticism, critical thinking, and the scientific method. A couple of years ago I wrote that Tyson has in the estimation of many, myself included, come to occupy the place in our culture once filled by the late Carl Sagan, so it was fitting that earlier this year PBS announced that he is being tapped to host an updated version of Sagan's epic Cosmos series from 1980. I can't wait to see it.. Also, just so you know, both he and I would agree that the fact that his birthday happens to fall during Space Week is a simple coincidence. Uncanny certainly, but nothing more.
To start off today's discussion, I will refer to another person I greatly admire, Isaac Asimov. One of the towering science fiction writers of the 20th century, he also wrote a great deal of non-fiction (about 75% of everything he wrote, actually), and while I can't remember in what essay or article I read it, a quote of his seems very applicable to the recent news about neutrinos: "The most exciting phrase to hear in science, the only one that heralds new discoveries, is not 'Eureka!', but rather, 'Hmm... that’s funny...'."
While particle physics does not usually make headlines, a couple of weeks ago some jaw-dropping results from an experiment conducted by the Center for European Nuclear Research (CERN, the acronym for the laboratory's name in French) were made public and set the media on fire. Situated on the border between France and Switzerland, CERN had been sending a stream of neutrinos to an underground detector several hundred miles away in Italy. It was a pretty routine experiment to see how often one type of neutrino changed into another, but the folks in Italy noticed that the neutrinos were arriving just slightly a bit sooner than they should have been. Now neutrinos are thought to have no mass, and so like other massless particles (photons, principally) they travel at the speed of light. Thus their early arrival at the Italian detector, even if only by a few billionths of a second, appears to indicate that these neutrinos were traveling faster than light. Let that sink in for a minute. For more than a century one of the cornerstones of physics has been that nothing, yeah you heard that, nothing travels faster than light. The speed of light has been measured countless times, with ever growing degrees of precision and accuracy, and countless experiments have been conducted which without exception have confirmed this absolute speed limit. So if the CERN findings are confirmed it means we need to seriously rethink the two main theories that underpin our understanding of the Universe: Einstein's Relativity (both Special and General) and the Standard Model, which is the basis for quantum physics.
Lost in much of the ballyhoo that attended the CERN announcement was the fact that the potentially trailblazing results were not even related to what the original experiment was studying. So somewhere some scientist saying "Hmm...that's funny..." (or its French equivalent) is what started all of this. Now interestingly enough, it appears that this was not the first time neutrinos were observed breaking the light barrier. A few years ago a similar experiment that was conducted by Fermilab in Illinois produced the same eyebrow raising data when the neutrinos reached the detector at the Soudan Underground Mine facility in northern Minnesota (I've been there, it is a cool place, especially if you are a Battlestar Galactica fan). However those results were within the boundaries of experimental error, and so did not generate nearly as much publicity. But in the wake of the CERN announcement they are being revisited and laboratories around the world are racing to replicate the results. At the moment, the jury is still out on whether we will have to incorporate a new factor into the equations that describe reality, and it may be that some other team will find something that explains the discrepancy, but that is how science works. The CERN scientists combed over their results for six months, trying their best to account for anything that may have introduced an error or affected their calculations, and only after their searches turned up nothing did they reveal the findings to the rest of the scientific community. While nothing is sacred in science, you want to be pretty damn sure your observations are spot on when they could challenge a theory as rock-solid as Relativity, and if those observations can't be replicated then they will go down as a (for now) unexplained fluke and the theory will continue to be the standard.
Even though it has only been a couple of weeks since the announcement, many possible explanations for our supraluminal neutrinos have already been proposed. Some involve extra dimensions they take a shortcut through, others more prosaic things like flaws in equipment calibration, but all are highly technical so I'll spare the details. How will this all play out? I have no idea, but in order to truly make one's peace with the Universe you have to get comfortable with uncertainty, and not just in the narrow Heisenbergian sense. These are the sorts of situations that get science buffs like me extremely excited, because this is when science is at its best. For in science the news that something we thought was true might be wrong, even in only the most tiny of ways, is cause for exhilaration, not dread, and I can only imagine how the scientists actually working on the CERN results are feeling. We live in interesting times, folks, and have once again been reminded that the three most revolutionary words in the English language, or most any other for that matter, are "Hmm...that's funny..."
Tuesday, October 4, 2011
Space Week 2011 #1: "The Dawn of a New Era"
Greetings, everyone.
Welcome to the first Space Week article of 2011. Fifty-four years ago today (I am publishing this on the 4th, but just barely) the first artificial satellite Sputnik I was launched into orbit, marking the beginning of humanity's exploration of the Universe beyond our planet and its atmosphere. Today's topic has to do with the Dawn spacecraft, and I admit I was seriously considering "Breaking Dawn" for the title, if only to get some stray "Twilight" fan-girl traffic directed here, where they would then read something of value for a change. Maybe just having the phrase in the previous sentence will be enough, but in any case let us delve into the matter at hand.
Those of you who have been Space Week readers for many years may recall mentions of the Dawn spacecraft and its mission in previous editions. The mission is of great interest to me for three major reasons. First, it is the first spacecraft to orbit and study any object in the main asteroid belt. Other missions have made brief flybys of such objects en route to their intended destinations, but this time the main belt is the destination. Second, it will be the first spacecraft to orbit and study one object, and then break orbit and travel to and study a second distinct object. Dawn has already reached its first target, the main belt asteroid Vesta, and is currently in the middle of its year-long investigation of this fascinating not-quite-planet. Next summer it will leave Vesta and travel to Ceres, a dwarf planet and the largest object in the asteroid belt, arriving in February 2015 for a stay of at least six months. Third, Dawn is the first full-scale mission to employ the ion engine as its primary means of propulsion.
So why the asteroid belt? Well, it is quite an interesting place. There are, however, a few myths about it that should be addressed before proceeding further. The most prominent of them is that it is the Solar System's equivalent of a shooting gallery. While it is true that there are a lot of asteroids that orbit in the main belt (otherwise it wouldn't be the main belt, would it?) the distances between them are so large that one could easily pass through the whole thing without running into a single one, and in fact many spacecraft have. Though the boundaries are somewhat diffuse, the main belt is usually considered to begin at around 2 AU (astronomical units, a measurement defined as the average distance between the Sun and the Earth, around 93 million miles, and useful when dealing with distances within the Solar System) and end around 3.25 AU. This is from slightly beyond the orbit of Mars to about half of the distance between that planet and Jupiter. That is quite a large amount of space, so even if it were populated by millions of asteroids, as some have theorized, there is more than enough room to both accommodate them and ensure that anything traversing the belt does not get pulverized (assuming that is its goal).
Also, the asteroid belt is not some sort of time capsule, filled with leftover material from the formation of the Solar System that has remained there until the present relatively unchanged. Though there are some objects in the main belt that fit this description, the belt itself and its residents have changed over time, mostly due to the presence of the planet beyond its outer edge. I have written before of the dominant role Jupiter has played in the evolution of the Solar System, so suffice it to say here that its gravitational influence has worked both to keep the material in the belt from initially forming into a planet and to subsequently mess with the orbits of everything that happens to be there. Thus many asteroids that are in the main belt now did not start there, and many that did are for various reasons no longer around. And while it most definitely is not a shooting gallery, there are collisions between asteroids that alter their compositions. Finally, some of the larger ones may be subject to geologic forces similar to those found on Earth, pushing them even further from their initial state.
That being said, one of Dawn's primary purposes is to shed light on the formation and evolution of planets. Its two targets, Vesta and Ceres, are the largest objects in the asteroid belt (#2 and #1, respectively), and have stayed more or less where they were to start out. However, they are very different from each other, and studying them will help to solve important questions about how various processes play out over time. Vesta, following Ceres' reclassification as a dwarf planet, is the most massive of the asteroids, having an irregular shape but a differentiated interior (meaning various types of rocks have congregated together under internal gravity, rather than remaining randomly distributed). One question Vesta may help to answer is how and when magnetic fields arise on planets. Apparently Vesta's rocks are more strongly magnetized than those of Mars, possibly as the result of a massive collision it suffered around a billion years ago, so data from Dawn may help us understand how and why Mars lost its magnetic field, and how our own may change in the future. Ceres is by far the largest object in the asteroid belt, and since it is spherical it is now considered a dwarf planet. Ceres has a great deal of ice on its surface, could have seasonal polar caps, and may even harbor an ocean below its icy shell, all of which make it a place of great interest. One question Ceres could help answer is how the oceans formed on Earth. There are a few theories out there, and one of them involves a number of objects similar in composition to Ceres, though not as large, being thrown at us by Jupiter during the early period of intense and heavy bombardment the Earth sustained before things calmed down a little. So data from Dawn may help us understand whether or not this theory is plausible, as well as give us another example of how water and ice work to shape a planet over time.
The thing that will enable Dawn to do all of this is its ion engine. First tested by the Deep Space 1 probe in the late 90's, the ion engine has the potential to open up many new regions of the Solar System to exploration. Much more compact, more versatile, and longer lasting than traditional chemical rockets, the ion engine uses the thrust generated by charged particles (in Dawn's case Xenon gas) to move a spacecraft. It starts out slow, but since an ion engine can operate continuously over periods of several years, it can build up speeds similar to those rockets can provide while being more efficient, less bulky, and more reliable. It is also what will enable Dawn to leave Vesta and travel to Ceres for the second leg of its mission, something that would be extremely difficult for a traditional rocket powered spacecraft. Of course, Dawn did require a rocket to leave Earth's gravity well, but after that it has been clear ion sailing. The other feature of ion engines is that they take a long time to get you where you want to go (Dawn took a little less than four years to reach Vesta, and will take another 2.5 to get to Ceres) but when you consider that an ion engine needs a lot less fuel to get there, and that traditional rockets and their fuel is expensive (usually to the tune of around 50% of any mission's total cost), it is well worth the wait. Thus I hope that the ion engine will soon become the method of choice for robotic exploration, and that Dawn's success will inspire many more ambitious missions that will unlock the secrets of our Solar System.
There are, of course, many online resources for those who wish to learn more about Dawn, the asteroid belt, and ion propulsion. The best place to start is the Dawn mission home page, and to follow your curiosity after that. Next up we will discuss some recent news that has the potential to really shake up physics as we have understood it for the past century.
Welcome to the first Space Week article of 2011. Fifty-four years ago today (I am publishing this on the 4th, but just barely) the first artificial satellite Sputnik I was launched into orbit, marking the beginning of humanity's exploration of the Universe beyond our planet and its atmosphere. Today's topic has to do with the Dawn spacecraft, and I admit I was seriously considering "Breaking Dawn" for the title, if only to get some stray "Twilight" fan-girl traffic directed here, where they would then read something of value for a change. Maybe just having the phrase in the previous sentence will be enough, but in any case let us delve into the matter at hand.
Those of you who have been Space Week readers for many years may recall mentions of the Dawn spacecraft and its mission in previous editions. The mission is of great interest to me for three major reasons. First, it is the first spacecraft to orbit and study any object in the main asteroid belt. Other missions have made brief flybys of such objects en route to their intended destinations, but this time the main belt is the destination. Second, it will be the first spacecraft to orbit and study one object, and then break orbit and travel to and study a second distinct object. Dawn has already reached its first target, the main belt asteroid Vesta, and is currently in the middle of its year-long investigation of this fascinating not-quite-planet. Next summer it will leave Vesta and travel to Ceres, a dwarf planet and the largest object in the asteroid belt, arriving in February 2015 for a stay of at least six months. Third, Dawn is the first full-scale mission to employ the ion engine as its primary means of propulsion.
So why the asteroid belt? Well, it is quite an interesting place. There are, however, a few myths about it that should be addressed before proceeding further. The most prominent of them is that it is the Solar System's equivalent of a shooting gallery. While it is true that there are a lot of asteroids that orbit in the main belt (otherwise it wouldn't be the main belt, would it?) the distances between them are so large that one could easily pass through the whole thing without running into a single one, and in fact many spacecraft have. Though the boundaries are somewhat diffuse, the main belt is usually considered to begin at around 2 AU (astronomical units, a measurement defined as the average distance between the Sun and the Earth, around 93 million miles, and useful when dealing with distances within the Solar System) and end around 3.25 AU. This is from slightly beyond the orbit of Mars to about half of the distance between that planet and Jupiter. That is quite a large amount of space, so even if it were populated by millions of asteroids, as some have theorized, there is more than enough room to both accommodate them and ensure that anything traversing the belt does not get pulverized (assuming that is its goal).
Also, the asteroid belt is not some sort of time capsule, filled with leftover material from the formation of the Solar System that has remained there until the present relatively unchanged. Though there are some objects in the main belt that fit this description, the belt itself and its residents have changed over time, mostly due to the presence of the planet beyond its outer edge. I have written before of the dominant role Jupiter has played in the evolution of the Solar System, so suffice it to say here that its gravitational influence has worked both to keep the material in the belt from initially forming into a planet and to subsequently mess with the orbits of everything that happens to be there. Thus many asteroids that are in the main belt now did not start there, and many that did are for various reasons no longer around. And while it most definitely is not a shooting gallery, there are collisions between asteroids that alter their compositions. Finally, some of the larger ones may be subject to geologic forces similar to those found on Earth, pushing them even further from their initial state.
That being said, one of Dawn's primary purposes is to shed light on the formation and evolution of planets. Its two targets, Vesta and Ceres, are the largest objects in the asteroid belt (#2 and #1, respectively), and have stayed more or less where they were to start out. However, they are very different from each other, and studying them will help to solve important questions about how various processes play out over time. Vesta, following Ceres' reclassification as a dwarf planet, is the most massive of the asteroids, having an irregular shape but a differentiated interior (meaning various types of rocks have congregated together under internal gravity, rather than remaining randomly distributed). One question Vesta may help to answer is how and when magnetic fields arise on planets. Apparently Vesta's rocks are more strongly magnetized than those of Mars, possibly as the result of a massive collision it suffered around a billion years ago, so data from Dawn may help us understand how and why Mars lost its magnetic field, and how our own may change in the future. Ceres is by far the largest object in the asteroid belt, and since it is spherical it is now considered a dwarf planet. Ceres has a great deal of ice on its surface, could have seasonal polar caps, and may even harbor an ocean below its icy shell, all of which make it a place of great interest. One question Ceres could help answer is how the oceans formed on Earth. There are a few theories out there, and one of them involves a number of objects similar in composition to Ceres, though not as large, being thrown at us by Jupiter during the early period of intense and heavy bombardment the Earth sustained before things calmed down a little. So data from Dawn may help us understand whether or not this theory is plausible, as well as give us another example of how water and ice work to shape a planet over time.
The thing that will enable Dawn to do all of this is its ion engine. First tested by the Deep Space 1 probe in the late 90's, the ion engine has the potential to open up many new regions of the Solar System to exploration. Much more compact, more versatile, and longer lasting than traditional chemical rockets, the ion engine uses the thrust generated by charged particles (in Dawn's case Xenon gas) to move a spacecraft. It starts out slow, but since an ion engine can operate continuously over periods of several years, it can build up speeds similar to those rockets can provide while being more efficient, less bulky, and more reliable. It is also what will enable Dawn to leave Vesta and travel to Ceres for the second leg of its mission, something that would be extremely difficult for a traditional rocket powered spacecraft. Of course, Dawn did require a rocket to leave Earth's gravity well, but after that it has been clear ion sailing. The other feature of ion engines is that they take a long time to get you where you want to go (Dawn took a little less than four years to reach Vesta, and will take another 2.5 to get to Ceres) but when you consider that an ion engine needs a lot less fuel to get there, and that traditional rockets and their fuel is expensive (usually to the tune of around 50% of any mission's total cost), it is well worth the wait. Thus I hope that the ion engine will soon become the method of choice for robotic exploration, and that Dawn's success will inspire many more ambitious missions that will unlock the secrets of our Solar System.
There are, of course, many online resources for those who wish to learn more about Dawn, the asteroid belt, and ion propulsion. The best place to start is the Dawn mission home page, and to follow your curiosity after that. Next up we will discuss some recent news that has the potential to really shake up physics as we have understood it for the past century.
Monday, October 3, 2011
Space Week 2011 Kickoff
[For those of you new to this, every October since the fall of 2000 I have written a series of space-related articles in honor of the United Nations World Space Week that runs Oct. 4-10. Though they cover a broad range of topics, many of them touch on public policy, economics, or political issues, and are thus appropriate for this forum. Now on with the show.]
Man, where does the time go?
I've been working on a couple of other projects over the past several weeks, so it only recently hit me that SPACE WEEK STARTS TOMORROW!! Maybe today if you read this after midnight on the 4th, which is likely most of you.
Yes, our annual extravaganza of all things supraterran is about to begin. Once again to keep things manageable I will be posting articles throughout the month of October, but since I already have more than enough timely and interesting issues to write about, not to mention a backlog of requests from previous years, I am forgoing the usual topic solicitation.
The lineup for this year is as follows:
1: "The Dawn of a New Era"
2: "Hmm, That's Funny?" or "Dem Wacky Neutrinos"
3: "50 Years of Human Spaceflight" (official WSW 2011 theme)
4: "Red Rover, Red Rover, Send Curiosity Right Over"
5: "Is the Private Space Industry Ready for Takeoff?"
6: "The Voyagers and the Making of a Space Geek"
7: "Back to Basics: The Cosmic Perspective"
As always, I welcome any questions, comments or suggestions these pieces may inspire.
I hope you all enjoy the ride.
Man, where does the time go?
I've been working on a couple of other projects over the past several weeks, so it only recently hit me that SPACE WEEK STARTS TOMORROW!! Maybe today if you read this after midnight on the 4th, which is likely most of you.
Yes, our annual extravaganza of all things supraterran is about to begin. Once again to keep things manageable I will be posting articles throughout the month of October, but since I already have more than enough timely and interesting issues to write about, not to mention a backlog of requests from previous years, I am forgoing the usual topic solicitation.
The lineup for this year is as follows:
1: "The Dawn of a New Era"
2: "Hmm, That's Funny?" or "Dem Wacky Neutrinos"
3: "50 Years of Human Spaceflight" (official WSW 2011 theme)
4: "Red Rover, Red Rover, Send Curiosity Right Over"
5: "Is the Private Space Industry Ready for Takeoff?"
6: "The Voyagers and the Making of a Space Geek"
7: "Back to Basics: The Cosmic Perspective"
As always, I welcome any questions, comments or suggestions these pieces may inspire.
I hope you all enjoy the ride.
Subscribe to:
Posts (Atom)