The International Space Station as seen by the departing STS-134 crew on May 29, 2011. Credit: NASA
A spacecraft attached to the International Space Station did an “emergency maneuver” to push the complex, which now houses six people, away from a threatening piece of space debris Oct. 27, the European Space Agency said in a statement.
A hand-sized shard of the Russian Cosmos-2251 satellite, which collided with a U.S. Iridium satellite in 2009, would have come within at least four kilometers (2.5 miles) of the orbiting outpost. This was close enough for the space station partners to agree to a move six hours before the potential impact.
“This is the first time the station’s international partners have avoided space debris with such urgency,” the European Space Agency wrote. The push to a safer orbit took place using the agency’s automated transfer vehicle Georges Lemaître, which docked with the space station in August.
The International Space Station in October 2014, with the European automated transfer vehicle Georges Lemaître attached. Credit: Alexander Gerst/ESA/NASA
While many collision threats are spotted at least days before impact, occasionally ground networks aren’t able to see a piece until 24 hours or less before the potential impact. Since 2012, the space station has normally done last-minute maneuvers using Russian cargo Progress vehicles, but this time around none were docked there. This is where the ATV came in.
Controllers at the ATV control center in France then did a four-minute preprogrammed move that raised the station’s orbit by one kilometer (0.6 miles), enough to get out of the way.
The ATV is expected to remain at the station until February, when it will undock and burn up in the atmosphere. This is the last of the series of ATVs that Europe agreed to make as a part of its space station agreement.
The galactic core, observed using infrared light and X-ray light.
Credit: NASA, ESA, SSC, CXC, and STScI
The galactic center is a happening place, with lots of gas, dust, stars, and surprising binary stars orbiting a supermassive black hole about three million times the size of our sun. With so many stars, astronomers estimate that there should be hundreds of dead ones. But to date, scientists have found only a single young pulsar at the galactic center where there should be as many as 50.
The question thus arises: where are all those rapidly spinning, dense stellar corpses known as pulsars? Joseph Bramante of Notre Dame University and astrophysicist Tim Linden of the University of Chicago have a possible solution to this missing-pulsar problem, which they describe in a paper accepted for publication in the journal Physical Review Letters.
Maybe those pulsars are absent because dark matter, which is plentiful in the galactic center, gloms onto the pulsars, accumulating until the pulsars become so dense they collapse into a black hole. Basically, they disappeared into the fabric of space and time by becoming so massive that they punched a hole right through it.
Dark matter, as you may know, is the theoretical mass that astrophysicists believe fills roughly a quarter of our universe. Alas, it is invisible and undetectable by conventional means, making its presence known only in how its gravitational pull interacts with other stellar objects.
One of the more popular candidates for dark matter is Weakly Interacting Massive Particles, otherwise known as WIMPs. Underground detectors are currently hunting for WIMPs and debate has raged over whether gamma rays streaming from the galactic center come from WIMPs annihilating one another.
In general, any particle and its antimatter partner will annihilate each other in a flurry of energy. But WIMPs don’t have an antimatter counterpart. Instead, they’re thought to be their own antiparticles, meaning that one WIMP can annihilate another.
But over the last few years, physicists have considered another class of dark matter called asymmetric dark matter. Unlike WIMPs, this type of dark matter does have an antimatter counterpart.
Cosmic Infrared Background ExpeRIment (CIBER) simulation of the density of matter when the universe was one billion years old, as produced by large-scale structures from dark matter. Credit: Caltech/Jamie Bock
Asymmetric dark matter appeals to physicists because it’s intrinsically linked to the imbalance of matter and antimatter. Basically, there’s a lot more matter in the universe than antimatter – which is good considering anything less than an imbalance would lead to our annihilation. Likewise, according to the theory, there’s much more dark matter than anti-dark-matter.
Physicists think that in the beginning, the Big Bang should’ve created as much matter as antimatter, but something altered this balance. No one’s sure what this mechanism was, but it might have triggered an imbalance in dark matter as well – hence it is “asymmetric”.
Dark matter is concentrated at the galactic center, and if it’s asymmetric, then it could collect at the center of pulsars, pulled in by their extremely strong gravity. Eventually, the pulsar would accumulate so much mass from dark matter that it would collapse into a black hole.
The idea that dark matter can cause pulsars to implode isn’t new. But the new research is the first to apply this possibility to the missing-pulsar problem.
If the hypothesis is correct, then pulsars around the galactic center could only get so old before grabbing so much dark matter that they turn into black holes. Because the density of dark matter drops the farther you go from the center, the researchers predict that the maximum age of pulsars will increase with distance from the center. Observing this distinct pattern would be strong evidence that dark matter is not only causing pulsars to implode, but also that it’s asymmetric.
“The most exciting part about this is just from looking at pulsars, you can perhaps say what dark matter is made of,” Bramante said. Measuring this pattern would also help physicists narrow down the mass of the dark matter particle.
Artist’s illustration of a pulsar that was found to be an ultraluminous X-ray source. Credit: NASA, Caltech-JPL
But as Bramante admits, it won’t be easy to detect this signature. Astronomers will need to collect much more data about the galactic center’s pulsars by searching for radio signals, he claims. The hope is that as astronomers explore the galactic center with a wider range of radio frequencies, they will uncover more pulsars.
But of course, the idea that dark matter is behind the missing pulsar problem is still highly speculative, and the likelihood of it is being called into question.
“I think it’s unlikely—or at least it is too early to say anything definitive,” said Zurek, who was one of the first to revive the notion of asymmetric dark matter in 2009. The tricky part is being able to know for sure that any measurable pattern in the pulsar population is due to dark-matter-induced collapse and not something else.
Even if astronomers find this pulsar signature, it’s still far from being definitive evidence for asymmetric dark matter. As Kathryn Zurek of the Lawrence Berkeley National Laboratory explained: “Realistically, when dark matter is detected, we are going to need multiple, complementary probes to begin to be convinced that we have a handle on the theory of dark matter.”
And asymmetric dark matter may not have anything to do with the missing pulsar problem at all. The problem is relatively new, so astronomers may find more plausible, conventional explanations.
“I’d say give them some time and maybe they come up with some competing explanation that’s more fleshed out,” Bramante said.
Nevertheless, the idea is worth pursuing, says Haibo Yu of the University of California, Riverside. If anything, this analysis is a good example of how scientists can understand dark matter by exploring how it may influence astrophysical objects. “This tells us there are ways to explore dark matter that we’ve never thought of before,” he said. “We should have an open mind to see all possible effects that dark matter can have.”
There’s one other way to determine if dark matter can cause pulsars to implode: To catch them in the act. No one knows what a collapsing pulsar might look like. It might even blow up.
“While the idea of an explosion is really fun to think about, what would be even cooler is if it didn’t explode when it collapsed,” Bramante said. A pulsar emits a powerful beam of radiation, and as it spins, it appears to blink like a lighthouse with a frequency as high as several hundred times per second. As it implodes into a black hole, its gravity gets stronger, increasingly warping the surrounding space and time.
Studying this scenario would be a great way to test Einstein’s theory of general relativity, Bramante says. According to theory, the pulse rate would get slower and slower until the time between pulses becomes infinitely long. At that point, the pulses would stop entirely and the pulsar would be no more.
Missing the planets this month? With Mars receding slowly to the west behind the Sun at dusk, the early evening sky is nearly devoid of planetary action in the month of November 2014. Stay up until about midnight local, however, and brilliant Jupiter can be seen rising to the east. Well placed for northern hemisphere viewers in the constellation Leo, Jupiter is about to become a common fixture in the late evening sky as it heads towards opposition next year in early February.
The line-up during the November 25th eclipse event (see chart below). Note that Jupiter’s moons are in 1-2-3-4 order! Credit: Stellarium.
An interesting phenomenon also reaches its climax, as we make the first of a series of passes through the ring plane of Jupiter’s moons this week on November 8th, 2014. This means that we’re currently in a season where Jupiter’s major moons not only pass in front of each other, but actually eclipse and occult one another on occasion as they cast their shadows out across space.
These types of events are challenging but tough to see, owing to the relatively tiny size of Jupiter’s moons. Followers of the giant planet are familiar with the ballet performed by the four large Jovian moons of Io, Europa, Ganymede, and Callisto. This was one of the first things that Galileo documented when he turned his crude telescope towards Jupiter in late 1609. The shadows the moons cast back on the Jovian cloud tops are a familiar sight, easily visible in a small telescope. Errors in the predictions for such passages provided 17th century Danish astronomer Ole Rømer with a way to measure the speed of light, and handy predictions of the phenomena for Jupiter’s moons can be found here.
A look at selected upcoming occultation events. Credit: Starry Night.Credit and copyright Christoper Go, used with permission.
Mutual occultations and eclipses of the Jovian moons are much tougher to see. The moons range in size from 3,121 km (Europa) to 5,262 km (Ganymede), which translates to 0.8”-1.7” in apparent diameter as seen from the Earth. This means that the moons only look like tiny +6th magnitude stars even at high magnification, though sophisticated webcam imagers such as Michael Phillips and Christopher Go have managed to actually capture disks and tease out detail on the tiny moons.
A double shadow transit from 2013. Photo by author.
What is most apparent during these mutual events is a slow but steady drop in combined magnitude, akin to that of an eclipsing variable star such as Algol. Running video, Australian astronomer David Herald has managed to document this drop during the 2009 season (see the video above) and produce an effective light curve using LiMovie.
Such events occur as we cross through the orbital planes of Jupiter’s moons. The paths of the moons do not stray more than one-half of a degree in inclination from Jupiter’s equatorial plane, which itself is tilted 3.1 degrees relative to the giant planet’s orbit. Finally, Jupiter’s orbit is tilted 1.3 degrees relative to the ecliptic. Plane crossings as seen from the Earth occur once every 5-6 years, with the last series transpiring in 2009, and the next set due to begin around 2020. Incidentally, the slight tilt described above also means that the outermost moon Callisto is the only moon that can ‘miss’ Jupiter’s shadow on in-between years. Callisto begins to so once again in July 2016.
Mutual events for the four Galilean moons come in six different flavors:
A look at the six types of phenomena possible with Jupiter’s four large moons. Created by the author.
This month, Jupiter reaches western quadrature on November 14th, meaning that Jupiter and its moons sit 90 degrees from the Sun and cast their shadows far off to the side as seen from the Earth. This margin slims as the world heads towards opposition on February 6th, 2015, and Jupiter once again joins the evening lineup of planets.
Early November sees Jupiter rising around 1:00 AM local, about six hours prior to sunrise. Jupiter is also currently well placed for northern hemisphere viewers crossing the constellation Leo.
The Institut de Mécanique Céleste et de Calcul des Éphémérides (IMCCEE) based in France maintains an extensive page following the science and the circumstances for the previous 2009 campaign and the ongoing 2015 season.
We also distilled down a table of key events for North America coming up through November and December:
A look at selected events through the end of 2014. 1=Io, 2=Europa, 3=Ganymede, 4=Callisto. O=Occultation, E=Eclipse. Created by the author, adapted from the IMCCEE chart for the 2014-15 season.
Fun fact: we also discovered during our research for this piece that these events can also produce a total solar eclipse very similar to the near perfect circumstances enjoyed on the Earth via our Moon:
Note that this season also produces another triple shadow transit on January 24th, 2015.
Observing and recording these fascinating events is as simple as running video at key times. If you’ve imaged Jupiter and its moons via our handy homemade webcam method, you also possess the means to capture and analyze the eclipses and occultations of Jupiter’s moons.
A view never seen from the Earth… Io (upper left) paired with a crescent Europa during New Horizons’ 2007 flyby. Credit: NASA/JPL.
Good luck, and let us know of your tales of astronomical tribulation and triumph!
In this near-infrared mosaic, the sun shines off of the seas on Saturn's moon, Titan. Credit: NASA/JPL-Caltech/University of Arizona/University of Idaho
See that yellow smudge in the image above? That’s what the Sun looks like reflecting off the seas of Titan, that moon of Saturn that excites astrobiologists because its chemistry resembles what early Earth could have looked like. This image represents the first time this “sunglint” and Titan’s northern polar seas have been captured in one mosaic, NASA said.
What’s more, if you look closely at the sea surrounding the sunlight, you can see what scientists dub a “bathtub ring.” Besides looking pretty, this image from the Cassini spacecraft shows the huge sea (called Kraken Mare) was actually larger at some point in Titan’s past.
“The southern portion of Kraken Mare … displays a ‘bathtub ring’ — a bright margin of evaporate deposits — which indicates that the sea was larger at some point in the past and has become smaller due to evaporation,” NASA stated. “The deposits are material left behind after the methane and ethane liquid evaporates, somewhat akin to the saline crust on a salt flat.”
In this near-infrared global mosaic of Titan, sunglint and the moon’s polar seas are visible above the shadow. Credit: NASA/JPL-Caltech/University of Arizona/University of Idaho
The sunlight was so bright that it saturated the detector on Cassini that viewed it, called the Visual and Infrared Mapping Spectrometer (VIMS) instrument. The sun was about 40 degrees above the horizon of Kraken Mare then, which is the highest ever observed on Titan.
The T-106 flyby Oct. 23 was the second-to-last closeup view Cassini will have of Titan this year. The spacecraft has been circling Saturn’s system for more than 10 years, and is now watching Titan (and Saturn’s) northern hemisphere enter summer.
Titan is covered in a thick, orangey atmosphere that hid its surface from scientists the first time a spacecraft zoomed by it in the 1980s. Subsequent exploration (most especially by Cassini and a short-lived lander called Huygens) have revealed dunes on and near the equator and at higher altitudes, lakes of methane and ethane.
Building a lunar base might be easier if astronauts could harvest local materials for the construction, and life support in general. Credit: NASA/Pat Rawlings
So can we get off of Earth already and start building bases on the Moon or an asteroid? As highlighted in a recent Office of Science and Technology Policy blog post, one way to do that quickly could be to use resources on site. But how do we even get started? Can we afford to do it now, in this tough economic climate?
Universe Today spoke with Philip Metzger, a former senior research physicist at NASA’s Kennedy Space Center, who has explored this subject extensively on his website and in published papers. He argues that to do space this way would be similar to how the pilgrims explored North America. In the first of a three-part series, he outlines the rationale and the first steps to making it there.
UT: It’s been said that using resources on the Moon, Mars or asteroids will be cheaper than transporting everything from Earth. At the same time, there are inherent startup costs in terms of developing technology to do this extraction and also sending this equipment over there, among other things. How do we reconcile these two realities?
PM: Space industry will have a tremendous payback, but it will be costly to start. Several years ago I was frustrated because I didn’t think that commercial interests alone would be enough to get it fully started within our generation, so I asked the question, can we find an inexpensive way for the governments of the world (or philanthropists or others who may not have an immediate commercial interest) to get it started simply because of the societal benefits it will bring? That’s why my colleagues and I wrote the paper “Affordable Rapid Bootstrapping of Space Industry and Solar System Civilization.”
We are advocating a bootstrapping approach because it helps solve the problem of the high startup cost and it enables humanity to start reaping the benefits quickly, since we need them quickly. A bootstrapping approach works like this: instead of building all the hardware on Earth and sending it into space ready to start manufacturing things, we can send a reduced set of hardware into space and make only a little bit of what we need. We can send the rest of the manufactured parts from Earth and combine them with what we made in space. Over time we keep doing this until we evolve up to a full manufacturing capability in space.
On a clear day, astronauts aboard the ISS can see over 1,000 miles from Havana to Washington D.C. Image Credit: Chris Hadfield / NASA
This is how colonies on Earth built themselves up until eventually they were able to match the industry of their homelands. The pilgrims, for example, didn’t bring entire factories from Europe over on the Mayflower. Now it took hundreds of years to build up American industry, but with robotics and advanced manufacturing and with some intentionality we can get it done much more quickly at still an affordable price. We have done some rudimentary modeling of this bootstrapping approach and it looks as though it would be a small part of our annual space budget and it could establish the industry within just decades.
What I think is even more important than the cost is that with a bootstrapping approach we can get started right away. We don’t need to complete the entire design and development up front. It also spreads the cost over time so the annual expenses are very low. And it allows us time to evolve our strategy, to figure out what works and what will have more immediate economic payback, as we go along. Many people are looking for the immediate ways to get a payback in space, and there are some great ideas and I am sure they will be successful. One example is to set up a mining operation that refuels communication satellites in geosynchronous orbit. These sorts of activities will contribute to, and will benefit from, the effort to start industry in space, and they will generate revenue to fund their portion of the effort.
UT: Why do you feel the Moon is a good spot to start operations? What would be some activities to start with there? How do we move from there into the rest of the solar system?
When my colleagues and I wrote the paper, we were focused on the Moon in part because that was during NASA’s Constellation program to establish a lunar outpost. However, it is equally possible to use near-Earth asteroids to start this space industry, or to use both. In any case, we need to start space industry close to the Earth. That will keep transportation costs low during the startup. It also enables us to work with much shorter time delay in the radio communications, which is important in the early stages before robotics become sufficiently automated. Ideally the industry will be fully automated; we want robots to prepare the way for humans to follow.
The cancelled Constellation Program. Credit: NASA
However, if we think we will need humans during initial start-up of the industry – for example, to fix or troubleshoot broken hardware, or to do complex tasks that robots can’t yet do – then starting near Earth becomes even more important. It turns out that both the Moon and asteroids are excellent places to start industry. We now know that they have abundant water, minerals from which metals can be refined, carbon for making plastics, and so on. I am glad there are companies planning to develop mining in both locations so we can see what works best.
Another reason to start industry close to Earth is so it can have an early economic payback. In the end, when everything including spaceships and refueling depots are made in space by autonomous robotics, then industry becomes self-sustaining and it will pay us back inestimably for no further cost. Getting to that point requires some serious investment, though, and it will be easier to make the investments if we are getting something back. So what kinds of payback can it give us in the near-term? I keep a list of ideas how to make money in space, and there are about 19 items on the list, some crazy and some not so crazy. A few of the serious ideas include: space tourism; making and selling propellants to NASA for exploration and science missions; returning metals like platinum for sale on Earth; and manufacturing spare parts for other activities in space.
Artist’s rendition of a Moon Base. Credit: John Spencer/Space Tourism Society.
Some of the initial things we will do on the Moon or asteroids includes perfecting the low-gravity mining techniques, learning how to make solar cells out of regolith, and learning how to extract useful metals from minerals that would not be considered “ore” here on Earth. All of these are possible and require only modest investment to make them work.
It will take decades of effort to make space industry self-sustaining. Maybe 2 decades if we get started right away and work steadily, or maybe 5 decades if we have a lower level of funding. But if robotics advance as fast as the roboticists are expecting, soon there will be no manufacturing task a robot cannot do. When that day arrives, and we have set up a complete supply chain in space, then it will be an easy thing to send sets of hardware to the main asteroid belt to begin mining and manufacturing where there are billions of times the resources more than what we have on Earth.
Then, the industry could build landing craft to take equipment to the surface of Mars where it can build cities and eventually even terraform the planet. When we have machines that can use local resources to perform work and build copies of themselves, then they can perform the same role on dry worlds that biological life has performed here on our wet Earth. They can transform the environment and become the food chain so those worlds will be places where humanity can work and live. I realize this sounds too ambitious, but 20 to 50 years of technology growth is going to make a huge difference, and we are only talking about manufacturing – not rocket science — and that is something that we are already quite good at here on Earth. With just a little extrapolation into the future it is not a crazy idea.
Artist concept of a Moon base. Credit: NASA/Pat Rawlings.
UT: What are the main pieces of equipment and robotics that we need up there to accomplish these objectives?
PM: There is an interesting open source project developing what they call the “Global Village Construction Set.” It is 50 machines that will be capable of restarting civilization. It includes things like a windmill, a backhoe, and a 3D printer. What we need is the equivalent “Lunar/Asteroid Village Construction Set.”
A study was done by NASA in 1980 to determine what set of machines are needed in factories on the Moon to build 80% of their own parts. The other 20% would need to be supplied constantly from Earth. In our paper we argued that we can start at much less than 80% closure, making it more affordable and allowing us to start today, but the system should evolve until it reaches 100% closure. So the first set of hardware might make crude solar cells, metal, 3D printed metal parts, and rocket propellants.
Having just that will allow us to make a significant mass of the next generation of hardware as well as support the transportation network. Over time, we want to develop an entire supply chain which would be more extensive than just 50 different types of machines. But before we put anything in space we will want to test them in rugged locations here on Earth, and in the process we will discover what set of machines makes the most sense for the first generation. The idea is to learn as we go, so we can get started right away.
Apollo 15 astronauts David Scott and James Irwin practice LRV operations in Arizona, Nov. 2 1970 (Credit: NASA. Research by J.L. Pickering)
Between the years of 1969 and 1972 the astronauts of the Apollo missions personally explored the alien landscape of the lunar surface, shuffling, bounding, digging, and roving across six sites on the Moon. In order to prepare for their off-world adventures though, they needed to practice extensively here on Earth so they would be ready to execute the long laundry lists of activities they were required to accomplish during their lunar EVAs. But where on Earth could they find the type of landscape that resembles the Moon’s rugged, dusty, and — most importantly — cratered terrain?
Enter the Cinder Lakes Crater Fields of Flagstaff, Arizona.
The Cinder Lakes Crater Fields northeast of Flagstaff, near the famous San Francisco peaks and just south of the Sunset Crater volcano, were used for Apollo-era training because of the inherently lunar-like volcanic landscape. LRV practice as well as hand tool geology and lunar morphology training were performed there, as well as ALSEP – Apollo Lunar Surface Experiment Package – placement and setup practice.
The photo above shows Apollo 15 astronauts Dave Scott and Jim Irwin driving a test LRV nicknamed Grover along the rim of a small “lunar crater.” (This particular exercise was performed on Nov. 2, 1970… 44 years ago today!)
Detonation of a “lunar crater” in 1967 (USGS)
Although the craters might look similar to the ones found on the Moon, they were actually created by the USGS in 1967 by digging holes and filling them with various amounts of explosives, which were detonated to simulate different-sized lunar impact craters. The human-made craters ranged in size from 5-40 feet (1.5-12 meters) in diameter.
The two crater field sites at Cinder Lakes were chosen because of the specific surface geology: a layer of basaltic cinders covering clay beds, left over from an eruption of the Sunset Crater volcano 950 years ago. After the explosions the excavated lighter clay material spread out from the blast craters and across the fields, like ejecta from actual meteorite impacts. A total of 497 craters were made within two sites comprising 2,000 square feet.
Detonations were done in series to simulate ejected debris from cratering events of different ages. And one of the areas of Cinder Lakes was designed to specifically replicate craters found within a particular region of the Apollo 11 Mare Tranquillitatis landing site.
The completed Cinder Lakes Crater Field #1 in October 1967 (USGS)
Today only the largest craters can be distinguished at all in the publicly-accessible Cinder Lakes field, which has become popular with ATV enthusiasts. But a smaller field, fenced off to vehicles, still contains many of the original craters used by Apollo astronauts, softened by time and weather but still visible.
A couple of other areas were used as lunar analogue training fields as well, such as the nearby Merriam Crater and Black Canyon fields — the latter of which is now covered by a housing development. Geology field training exercises by Apollo astronauts were also performed at locations in Texas, New Mexico, Nevada, Oregon, Alaska, Idaho, Iceland, Mexico, the Grand Canyon, and the lava fields of Hawaii. But only in Arizona were actual craters made to specifically simulate the Moon!
Read more about the Cinder Lakes Crater Field in a presentation document (my main article source) by LPI’s Dr. David Kring, and you can find more recent photos of the Crater Lakes sites on this page by LPI’s Jim Scotti.
Goldstone delay-Doppler images of 2014 SC324 obtained on October 25. The images span an interval of about 45 minutes and show considerable rotation
by this object, which has an irregular and elongated shape. Credit: NASA/JPL
Looks like we dodged a bullet. A bullet-shaped asteroid that is. The 70-meter Goldstone radar dish, part of NASA’s Deep Space Network, grabbed a collage of photos of Earth-approaching asteroid 2014 SC324 during its close flyby last Friday October 24. These are the first-ever photos of the space rock which was discovered September 30 this year by the Mt. Lemmon Survey. The level of detail is amazing considering that the object is only about 197 feet (60-meters) across. You can also see how incredibly fast it’s rotating – about 30-45 minutes for a one spin.
A cropped version of the photo to more clearly see the asteroid’s shape. 2014 SC324 passed just 1.5 lunar distances from Earth last week. Credit: NASA/JPL
In the cropped version, the shape is somewhat clearer with the asteroid appearing some four times longer than wide. 2014 SC324 belongs to the Apollo asteroid class, named for 1862 Apollo discovered in 1932 by German astronomer Karl Reinmuth. Apollo asteroids follow orbits that occasionally cross that of Earth’s, making them a potential threat to our planet. The famed February 15, 2013 Chelyabinsk fireball, with an approximate pre-atmospheric entry size of 59 feet (18-m), belonged to the Apollo class.
Three classes of asteroids that pass near Earth or cross its orbit are named for the first member discovered — Apollo, Aten and Amor. Apollo asteroids like 2014 SC324 routinely cross Earth’s orbit, Atens also cross but have different orbital characteristics and Amors cross Mars’ orbit but miss Earth’s. Credit: ESA
Lance Benner and colleagues at Goldstone also imaged another Apollo asteroid that passed through our neighborhood on October 19 called 2014 SM143. This larger object, estimated at around 650 feet (200-m) across, was discovered with the Pan-STARRS 1 telescope on Mt. Haleakala in Hawaii on September 17. Tell me we’re not some shiny ball on a solar system-sized pool table where the players fortunately miss their shot … most of the time.
The Rice Speech words hold especially true when the NASA's goals seem challenged and suddenly not so close at hand. (Photo Credit: NASA)
Over the 50-plus years since President John F. Kennedy’s Rice University speech, spaceflight has proven to be hard. It doesn’t take much to wreck a good day to fly.
Befitting a Halloween story, rocket launches, orbital insertions, and landings are what make for sleepless nights. These make-or-break events of space missions can be things that go bump in the night: sometimes you get second chances and sometimes not. Here’s a look at some of the past mission failures that occurred at launch. Consider this a first installment in an ongoing series of articles – “Not Because They Are Easy.”
A still image from one of several videos of the ill-fated Antares launch of October 28, 2014, taken by engineers at the Mid-Atlantic Regional Spaceport, Wallops, VA. (Credit: NASA)
The evening of October 28, 2014, was another of those hard moments in the quest to explore and expand humanity’s presence in space. Ten years ago, Orbital Sciences Corporation sought an engine to fit performance requirements for a new launch vehicle. Their choice was a Soviet-era liquid fuel engine, one considered cost-effective, meeting requirements, and proving good margins for performance and safety. The failure of the Antares rocket this week could be due to a flaw in the AJ-26 or it could be from a myriad of other rocket parts. Was it decisions inside NASA that cancelled or delayed engine development programs and led OSC and Lockheed-Martin to choose “made in Russia” rather than America?
Here are other unmanned launch failures of the past 25 years:
Falcon 1, Flight 2, March 21, 2007. Fairings are hard. There are fairings that surround the upper stage engines and a fairing covering payloads. Fairings must not only separate but also not cause collateral damage. The second flight of the Falcon 1 is an example of a 1st stage separation and fairing that swiped the second stage nozzle. Later, overcompensation by the control system traceable to the staging led to loss of attitude control; however, the launch achieved most of its goals and the mission was considered a success. (View: 3:35)
Proton M Launch, Baikonur Aerodrome, July 2, 2013. The Proton M is the Russian Space program’s workhorse for unmanned payloads. On this day, the Navigation, Guidance, and Control System failed moments after launch. Angular velocity sensors of the guidance control system were installed backwards. Fortunately, the Proton M veered away from its launch pad sparing it damage.
Ariane V Maiden Flight, June 4, 1996. The Ariane V was carrying an ambitious ESA mission called Cluster – a set of four satellites to fly in tetrahedral formation to study dynamic phenomena in the Earth’s magnetosphere. The ESA launch vehicle reused flight software from the successful Ariane IV. Due to differences in the flight path of the Ariane V, data processing led to a data overflow – a 64 floating point variable overflowing a 16 bit integer. The fault remained undetected and flight control reacted in error. The vehicle veered off-course, the structure was stressed and disintegrated 37 seconds into flight. Fallout from the explosion caused scientists and engineers to don protective gas masks. (View: 0:50)
Delta II, January 17, 1997. The Delta II is one of the most successful rockets in the history of space flight, but not on this day. Varied configurations change up the number of solid rocket motors strapped to the first stage. The US Air Force satellite GPS IIR-1 was to be lifted to Earth orbit, but a Castor 4A solid rocket booster failed seconds after launch. A hairline fracture in the rocket casing was the fault. Both unspent liquid and solid fuel rained down on the Cape, destroying launch equipment, buildings, and even parked automobiles. This is one of the most well documented launch failures in history.
Compilation of Early Launch Failures. Beginning with several of the early failures of Von Braun’s V2, this video compiles many failures over a 70 year period. The early US space program endured multiple launch failures as they worked at a breakneck speed to catch up with the Soviets after Sputnik. NASA did not yet exist. The Air Force and Army had competing designs, and it was the Army with the German rocket scientists, including Von Braun, that launched the Juno 1 rocket carrying Explorer 1 on January 31, 1958.
One must always realize that while spectacular to launch viewers, a rocket launch has involved years of development, lessons learned, and multiple revisions. The payloads carried involve many hundreds of thousands of work-hours. Launch vehicle and payloads become quite personal. NASA and ESA have offered grief counseling to their engineers after failures.
“We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win, and the others, too.”
Psst! Ever spy the planet Mercury? The most bashful of all the naked eye planets makes its best dawn appearance of 2014 this weekend for northern hemisphere observers. And not only will Mercury be worth getting up for, but you’ll also stand a chance at nabbing that most elusive of astronomical phenomena — the zodiacal light — from a good dark sky sight.
DST note: This post was written whilst we we’re visiting Arizona, a land that, we’re happy to report, does not for the most part observe the archaic practice of Daylight Saving Time. Life goes on, zombies do not arise, and trains still run on time. In the surrounding world of North America, however, don’t forget to “fall back” one hour on Sunday morning, November 2nd. I know, I know. Trust me, we didn’t design the wacky system we’re stuck with today. All times noted below post-shift reflect this change, but it also means that you’ll have to awaken an hour earlier Sunday November 2nd onwards to begin your astronomical vigil for Mercury!
The apparent daily path of Mercury as seen from 30 degrees north from October 21st to November 14th. Created using Starry Night Education Software.
Mercury starts the month of November reaching greatest elongation on Saturday, November 1st at 18.7 degrees west of the Sun at 13:00 Universal Time UT/09:00 EDT. Look for Mercury about 10 degrees above the eastern horizon 40 minutes before sunrise. The planet Jupiter and the stars Denebola and Regulus make good morning guideposts to trace the line of the ecliptic down to the horizon to find -0.3 magnitude Mercury.
Mars, Mercury and the International Space Station caught during an evening apparition in 2013. (Photo by author)
Sweeping along the horizon with binoculars, you may just be able to spy +0.2 magnitude Arcturus at a similar elevation to the northwest. The +1st magnitude star Spica also sits to Mercury’s lower right. Mercury passes 4.2 degrees north of Spica on November 4th while both are still about 18 degrees from the Sun, making for a good study in contrast.
Later in the month, the old waning crescent Moon will present a challenge as it passes 2.1 degrees north of Mercury on November 21st, though both will only be 9 degrees from the Sun on this date.
Mercury also passes 1.6 degrees south of Saturn November 26th, but both are only 7 degrees from the Sun and unobservable at this point. But don’t despair, as you can always watch all of the planetary conjunction action via SOHO’s sunward staring LASCO C3 camera, which has a generous 15 degree field of view.
Mercury (the bright ‘star’ with spikes) transits SOHO’s LASCO C3 camera. Credit: NASA/ESA/SOHO.
At the eyepiece, Mercury starts off the month of November as a 57% illuminated gibbous disk about 7” in diameter. This will change to a 92% illuminated disk 5″ across on November 15th, as the planet races towards superior conjunction on the far side of the Sun on December 8th. As with Venus, Mercury always emerges in the dawn sky as a crescent headed towards full phase, and the cycle reverses for both planets when they emerge in the dusk sky.
Why aren’t all appearances of Mercury the same? Mercury orbits the Sun once every 88 days, making greatest elongations of Mercury far from uncommon: on average, we get three dawn and three dusk apparitions of the innermost world per year, with a maximum of seven total possible. Two main factors come into play to assure that not all appearances of Mercury are created equal.
A depiction of the evening motion of Mercury and Venus as seen from Earth. Credit: NASA.
One is the angle of the ecliptic, which is the imaginary plane of our solar system that planets roughly follow traced out by the Earth’s orbit. In northern hemisphere Fall, this angle is at its closest to perpendicular at dawn, and the dusk angle is most favorable in the Spring. In the southern hemisphere, the situation is reversed. This serves to place Mercury as high as possible out of the atmospheric murk during favorable times, and shove it down into near invisibility during others.
The second factor is Mercury’s orbit. Mercury has the most elliptical orbit of any planet in our solar system at a value of 20.5% (0.205), with an aphelion of 69.8 million kilometres and perihelion 46 million kilometres from the Sun. This plays a more complicated role, as an elongation near perihelion only sees the planet venture 18.0 degrees from the Sun, while aphelion can see the planet range up to 27.8 degrees away. However, this distance variation also leads to noticeable changes in brightness that works to the advantage of Mercury spotters in the opposite direction. Mercury shines as bright as magnitude -0.3 at closer apparitions, to a full magnitude fainter at more distant ones at +0.7.
In the case of this weekend, greatest elongation for Mercury occurs just a week after perihelion, which transpired on October 25th.
Mercury transits the Sun earlier this year as captured by the Curiosity rover on Mars. Credit: NASA/JPL.
Mercury is also worth keeping an eye on in coming years, as it will also transit the Sun for the first time since 2006 on May 9th, 2016. This will be visible for Europe and North America. We always thought it a bit strange that while rarer transits of Venus have yet to make their sci-fi theatrical debut, a transit of Mercury does crop up in the film Sunshine.
The first week of November is also a fine time to try and spy the zodiacal light. This is a cone-shaped glow following the plane of the ecliptic, resulting from sunlight backscattered across a dispersed layer of interplanetary dust. The zodiacal light was a common sight for us from the dark skies of Arizona, often rivaling the distant glow of Tucson over the mountains. The zodiacal light vanished from our view after moving to the humid and often light polluted U.S. East Coast, though we’re happy to report that we can once again spy it as we continue to traverse the U.S. southwest this Fall.
The zodiacal light captured by Cory Schmitz over the Drakensberg Mountains in South Africa. (Used with permission).
None other than rock legend Brian May of Queen fame wrote his PhD dissertation on the zodiacal light and the distribution and relative velocity of dust particles along the plane of the solar system. Having a dark site and a clear flat horizon is key to nabbing this bonus to your quest to cross Mercury off your life list this weekend!
Comet C/2012 K1 PanSTARRS, one of the most dependable comets of 2014, may put on its encore performance over the coming weeks for southern hemisphere observers.
First, the story thus far. Discovered as a +19th magnitude smudge along the borders of the constellations Ophiuchus and Hercules in mid-May 2012 courtesy of the Panoramic Survey Telescope And Rapid Response System (PanSTARRS) based atop Haleakala on the Hawaiian island of Maui, astronomers soon realized that comet C/2012 K1 PanSTARRS would be something special.
The comet broke +10th magnitude to become a visible binocular object in early 2014, and wowed northern hemisphere observers as it vaulted across the constellations of Boötes and Ursa Major this past spring.
NASA’s NEOWISE mission spies K1 PanSTARRS on May 20th as it slides by the galaxy NGC 3726 (blue). Credit: NASA/JPL.
The comet is approaching the inner solar system on a retrograde, highly-inclined orbit tilted 142 degrees relative the ecliptic. This bizarre orbit also assures that the comet will actually reach opposition twice in 2014 as seen from our earthly vantage point: once on April 15th, and another opposition coming right up on November 7th.
As was the case with comet Hale-Bopp way back in 1997, had C/2012 K1 PanSTARRS arrived six months earlier or later, we would’ve been in for a truly spectacular show, as the comet reached perihelion on August 27th, 2014, only 0.05 A.U.s (4.6 million miles or 7.7 million kilometres) outside the orbit of the Earth! But such a spectacle was not to be… back in ’97, Hale-Bopp’s enormous size — featuring a nucleus estimated 40 to 60 kilometres across — made for a grand show regardless… fast forward to 2014, and the tinier nucleus of K1 PanSTARRS has been relegated to binocular status only.
The position of comet K1 PanSTARRS as it passes its second opposition of the year. Credit: NASA/JPL.
From here on out, K1 PanSTARRS is headed south “with a bullet” and into memory for most northern hemisphere observers. We spied the comet this morning low to the south near +3rd magnitude Nu Puppis in the pre-dawn sky with our trusty 15×45 binocs from Yuma, Arizona, for what will probably be our last time. This also means that the time to catch a last glimpse of K1 PanSTARRS for northern hemisphere viewers is now. This week sees the comet transiting just 20 degrees above the southern horizon at 3:00 to 4:00 AM local for observers based from latitude 30 degrees north as it crosses the constellation Puppis. The bright star Sirius nearly shares the same position as the comet in right ascension this week, and K1 PanSTARRS sits about 24 degrees south of the Dog Star.
Comet K1 PanSTARRS imaged on June 14th. Credit: Efrain Morales.
Halloween sees the comet even lower, crossing the southern meridian at only 13 degrees elevation as seen from latitude 30 degrees north. Draw a straight line from Sirius to the south celestial pole around this date to find the comet just 5 degrees to the north of Canopus.
But the show is just beginning for southern hemisphere residents. Observing from the town of Bright Australia, Robert Kaufmann recently noted in a posting on the Yahoo Groups Comet Observer’s message board that the comet currently exhibits a 4’ wide coma shining at about magnitude +7.3 with an elevation of 28 degrees above the horizon on October 25th.
And if the comet holds steady in brightness, it may break the visual threshold and become a naked eye object as seen from a dark sky site in early November.
The projected light curve of K1 PanSTARRS with brightness observations (black dots). The vertical pink line marks the comet’s perihelion passage in late August. Credit: Seiichi Yoshida’s Weekly Information on Bright Comets.
The comet will be literally “hauling tail” across the constellation Dorado as it nears its second opposition of the year on November 7th, moving about 1.5 degrees a day – 3 times the apparent diameter of the Full Moon – on closest approach.
Currently, the comet has been observed to have an estimated magnitude holding steady at+7 and is predicted to peak at perhaps magnitude +6 early next month. And while it would’ve been great had it arrived 6 months earlier or later, the aforementioned high retrograde inclination of its orbit assured that K1 PanSTARRS was a top performer for both hemispheres in 2014.
Perihelion passage occurred two months ago, but to paraphrase a famous Monty Python skit, Comet K1 PanSTARRS is “not dead yet.” Here are some key observing dates coming right up as the comet gains prominence in the southern hemisphere sky:
(Note that close passages of less than one degree near stars +4th magnitude or brighter only are mentioned).
Oct 31st: Passes closest to Earth, at 0.953 A.U.s distant.
Nov 1st: Crosses into the constellation Pictor.
Nov 2nd: Passes near the +3.8 magnitude star Beta Pictoris.
Nov 6th: Crosses into the constellation Dorado.
Nov 6th: Full Moon occurs, marking the beginning of an unfavorable week for comet hunting.
Nov 7th: The second opposition of the comet for 2014 occurs at 3:00 UT.
Nov 8th: Passes near the +3.3 magnitude star Alpha Doradus.
Nov 11th: Crosses into the constellation Reticulum.
Nov 13th: Crosses into the constellation Horologium.
Nov 14th: Passes 34 degrees from the South Celestial Pole.
Nov 20th: Crosses into the constellation Eridanus.
Nov 22nd: New Moon occurs, marking a week long span optimal for comet-hunting.
Nov 25th: Crosses into the constellation Phoenix.
The path of K1 PanSTARRS from October 27th through December 1st. Created by the author using Starry Night Education Software.
Dec 6th: Full Moon occurs.
Dec 12th: Passes near the +2.8 magnitude star Alpha Phoenicis (Ankaa).
Dec 18th: Crosses into the constellation Sculptor.
Dec 22nd: New Moon occurs.
Looking at 2015, K1 PanSTARRS will probably fall back below +10th magnitude by late January. The comet will then head back out into the depths of the outer solar system, its multi-million year orbit only slightly altered by its inner solar system passage down into the ~700,000 year range. What will Earth be like on that far off date? Will human eyes greet the comet once again, and will anyone remember its appearance way back in the mists of time in 2014? All thoughts to ponder as we bid fair well to Comet C/2012 K1 PanSTARRS, a fine binocular comet indeed.
