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.
Ambition is a collaboration between Platige Image and ESA. Shot on location in Iceland, it is directed by Tomek Bagi?ski and stars Aiden Gillen and Aisling Franciosi. Does Ambition accomplish more in 7 minutes than Gravity did in 90? Consider the abstraction of the Rosetta mission in light of NASA’s ambitions. (Credit: ESA, Illustration- TRR)
NASA has taken on space missions that have taken years to reach their destination; they have more than a dozen ongoing missions throughout the Solar System and have been to comets as well. So why pay any attention to the European Space Agency’s comet mission Rosetta and their new short film, “Ambition”?
‘Ambition’ might accomplish more in 7 minutes than ‘Gravity’ did in 90.
‘Ambition’ is a 7 minute movie created for ESA and Rosetta, shot on location in Iceland, directed by Oscar-winning Tomek Baginski, and stars Aidan Gillen—Littlefinger of ‘Game of Thrones.’ It is an abstraction of the near future where humans have become demigods. An apprentice is working to merge her understanding of existence with her powers to create. And her master steps in to assure she is truly ready to take the next step.
In the reality of today, we struggle to find grounding for the quest and discoveries that make up our lives on a daily basis. Yet, as the Ebola outbreak or the Middle East crisis reminds us, we are far from breaking away. Such events are like the opening scene of ‘Ambition’ when the apprentice’s work explodes in her face.
The ancient Greeks also took great leaps beyond all the surrounding cultures. They imagined themselves as capable of being demigods. Achilles and Heracles were born from their contact with the gods but they remained fallible and mortal.
The Comet Rendezvous and Flyby Mission conceived in one of two Mariner Mark II spacecraft was abandoned by the US Congress. The American led mission would have accomplished the objectives now being completed by the European Rosetta mission. (Photo Credit: NASA)
But consider the abstraction of the Rosetta mission in light of NASA’s ambitions. As an American viewing the European short film, it reminds me that we are not unlike the ancient Greeks. We have seen the heights of our powers and ability to repel and conquer our enemies, and enrich our country. But we stand manifold vulnerable.
In ‘Ambition’ and Rosetta, America can see our European cousins stepping ahead of us. The reality of the Rosetta mission is that a generation ago – 25 years — we had a mission as ambitious called Comet Rendezvous Asteroid Flyby (CRAF). From the minds within NASA and JPL, twin missions were born. They were of the Mariner Mark II spacecraft design for deep space. One was to Saturn and the other – CRAF was to a comet. CRAF was rejected by congress and became an accepted sacrifice by NASA in order to save its twin, the Cassini mission.
The short film ‘Ambition’ and the Rosetta mission is a reminder of what American ambition accomplished in the 60’s – Apollo, and the 70s – the Viking Landers, but then it began to falter in the 80s. The ambition of the Europeans did not lose site of the importance of comets. They are perhaps the ultimate Rosetta stones of our star system. They are unmitigated remnants of what created our planet billions of years ago unlike the asteroids that remained close to the Sun and were altered by its heat and many collisions.
Artist Illustration of the Cassini space probe to Saturn and Titan, a joint NASA, ESA mission. Cassini was the only Mariner Mark II spacecraft completed. (Photo Credit: NASA)
Our cousins picked up a scepter that we dropped and we should take notice that the best that Europe spawned in the last century – the abstract art of Picasso and Stravinsky, rocketry, and jet travel — remains alive today. Europe had the vision to continue a quest to something quite abstract, a comet, while we chose something bigger and more self-evident, Saturn and Titan.
‘Ambition’ shows us the forces at work in and around ESA. They blend the arts with the sciences to bend our minds and force us to imagine what next and why. There have been American epoch films that bend our minds, but yet sometimes it seems we hold back our innate drive to discover and venture out.
NASA recently created a 7 minute film of a harsh reality, the challenge of landing safely on Mars. ESA and Rosetta’s short film reminds us that we are not alone in the quest for knowledge and discovery, both of which set the stage for new growth and invention. America needs to take heed so that we do not wait until we reach the moment when an arrow pierces our heel as with Achilles and we succumb to our challengers.
Here comes another asteroid! 2014 SC324 will miss Earth by 1.5 times the distance to the Moon early Friday afternoon October 24, 2014. Credit: Gianluca Masi / Software Bisque
What a roller coaster week it’s been. If partial eclipses and giant sunspots aren’t your thing, how about a close flyby of an Earth-approaching asteroid? 2014 SC324 was discovered on September 30 this year by the Mt. Lemmon Surveyhigh in the Catalina Mountains north of Tucson, Arizona. Based on brightness, the tumbling rock’s size is estimated at around 197 feet (60-m), on the large side compared to the many small asteroids that whip harmlessly by Earth each year.
Near-Earth asteroid 2014 SC324 caught in the camera on October 23. The telescope tracked on the zippy space rock, causing the stars to trail. Credit: Gianluca Masi
Closest approach happens around 2 p.m. CDT (7 p.m. UT) Friday afternoon when our fast friend misses Earth by just 351,000 miles (565,000 km) or 1.5 times the distance to the Moon. This is a very safe distance, so we can finish up our lunches without a jot of concern. But the asteroid’s combination of size and proximity means amateur astronomers with a 10-inch or larger telescope will be able to track it across the sky beginning tonight (Oct. 23) and continuing through tomorrow night. 2014 SC324 should shine tolerably bright this evening at around magnitude +13.5.
Bright here is something of a euphemism, but when it comes to new Earth-approaching asteroids, this is within range of many amateur instruments. And because 2014 SC324 is “only” a half million miles away tonight, it’s not moving so fast that you can’t plot its arc on a single star chart, spot it and go for a ride.
Simulation based on recent data showing the known asteroids orbiting the Sun
By Friday evening, the new visitor will have faded a bit to magnitude +14. You can create a track for 2014 SC324 by inputting its orbital elements into a variety of astro software programs like MegaStar, the Sky, and Le Ciel. Elements are available via the Minor Planet Center and Horizons. Once saved, the program will make a track of the asteroid’s movement at selected time intervals. Print out the chart and you’re ready for the hunt!
Illustration of small asteroids passing near Earth. Credit: ESA / P. Carril
You can also go to Horizons, ask for a list of positions every 15 minutes for example and then hand plot those positions in right ascension (R.A.) and declination (Dec.) on a star map. This is what I do. I find the the general chunk of sky the asteroid’s passing through, print the map and then mark positions in pencil and connect them all with a line. Now I’ve got a chart I can use at the telescope based on the most current orbit.
Tonight the errant mountain will rumble through Aries the Ram, which is conveniently located in the eastern sky below Andromeda and the Great Square of Pegasus at nightfall.
Finding a dim, fast-moving object is doubtless an exciting challenge, but if you lack the equipment or the weather doesn’t cooperate, you can see the show online courtesy of Italian astrophysicist Gianluca Masi. He’ll stream the close encounter live on his Virtual Telescope Project website beginning at 7 p.m. CDT (midnight UT) tomorrow night October 24-25.
Which is the main culprit for the terminal Cretaceous extinction: the Chicxulub impact or Deccan Traps volcanism? Upper Image: Donald Davis, NASA JPL
Lower Image: USGS
About sixty five and a half million years ago, the Earth suffered its largest known cosmic impact. An asteroid or comet nucleus about 10 km in diameter slammed into what is now the Yucatan peninsula of Mexico. It gouged out a crater 180 to 200 km in diameter: nearly twice as large as the prominent crater Copernicus on Earth’s moon. But did this impact really cause the extinction of the dinosaurs and many other forms of life? Many earth scientists are convinced that it did, but some harbor nagging doubts. The doubters have marshaled a growing body of evidence for another culprit; the enormous volcanic eruptions that produced the Deccan Traps formation in India. The skeptics recently presented their case at a meeting of the Geological Society of America in Vancouver, Canada, on October 19.
The dinosaurs are the most well-known victims of the mass extinction event that ended the Cretaceous period. The extinction claimed almost all large vertebrates on land, at sea, or in the air, as well as numerous species of insects, plants, and aquatic invertebrates. At least 75% of all species then existing on Earth vanished in a short span in relation to the geological timescale of millions of years. The disaster is one of five global mass extinction events that paleontologists have identified over the tenure of complex life on Earth.
The hypothesis that the terminal Cretaceous extinction was caused by a cosmic impact has been the most popular explanation of this catastrophe among earth scientists and the public for several decades. It was proposed in 1980 by the father and son team of Luis and Walter Alvarez and their collaborators. The Alvarez team’s main line of evidence that an impact happened was an enrichment of the metal iridium in sediments dating roughly to the end of the Cretaceous. Iridium is rare in Earth’s crust, but common in meteorites. The link between iridium and impacts was first established by studies of the samples returned by the Apollo astronauts from the Moon.
Over the ensuing decades, evidence of an impact accumulated. In 1991, a team of scientists led by Dr. Alan Hildebrand of the Department of Planetary Sciences at Arizona University, published evidence of a gigantic buried impact crater, called Chicxulub, in Mexico. Other investigators found evidence of materials ejected by the impact, including glass spherules in Haiti and Mexico. Supporters of the impact hypothesis believe that vast amounts of dust hurtled into the stratosphere would have plunged the surface of the planet into the darkness and bitter cold of an “impact winter” lasting for at least months, and perhaps decades. Global ecosystems would have collapsed and mass extinction ensued. But, they’ve had a harder time finding evidence for these consequences than for the impact itself.
Doubters of the Alvarez hypothesis don’t question the ‘smoking gun’ evidence that an impact happened near the end of the Cretaceous, but they don’t think it was the main cause of the extinctions. For one thing, inferring the exact time of the impact from its putative geological traces has proved difficult. Dr. Gerta Keller of the Department of Geosciences of Princeton University, a prominent skeptic of the Alvarez hypothesis, has questioned estimates that make the impact and the extinctions simultaneous. Analyzing core samples taken from the Chicxulub crater, and glass spherule containing deposits in northeastern Mexico, she concludes that the Chicxulub impact preceded the mass extinction by 120,000 years and had little consequence for the fossil record of life in the geological formations which she studied. Of the five major mass extinction events in Earth’s history, she noted in a 2011 paper, none other than the terminal Cretaceous event has ever been even approximately associated with an impact. Several other large impact craters besides Chicxulub have been well studied by geologists and none is associated with fossil evidence of extinctions. On the other hand, four of the five major mass extinctions appear to have some connection with volcanic eruptions.
Keller and other Alvarez skeptics look to a major volcanic event that occurred towards the end of the Cretaceous as an alternate primary cause of the extinction. The Deccan Traps formation in central India is a plateau consisting of multiple layers of solidified lava 3500 m thick. Today, it extends over an area larger than all of France. It was once three times that large. It was formed in a series of three volcanic outbursts that may have been among the largest in Earth’s history. At the October conference, Dr. Theirry Adatte of the Institute of Earth Sciences at the University of Lausanne in France presented evidence that the second of these outbursts was by far the largest, and occurred over a period of 250,000 years prior to the end of the Cretaceous. During this period, 80% of the total lava thickness of the Deccan formation was deposited. The eruptions produced lava flows that may be the longest on Earth, extending more than 1500 km.
The blue area indicates the Deccan Traps, a massive remnant of immense volcanic eruptions at the end of the Cretaceous period that may have contributed to the terminal Cretaceous extinction. Credit: CamArchGrad, English Wikipedia Project
To illustrate the likely environmental consequences of such a super-eruption, Adatte invoked the worst volcanic catastrophe in human history. Over eight months from 1783-84 a major eruption in Laki, Iceland, deposited 14.3 square kilometers of lava and emitted an estimated 122 megatons of toxic sulfur dioxide into the atmosphere. About a quarter of the people and half of the livestock in Iceland died. Across Europe the sky was darkened by a pall of haze, and acid rain fell. Europe and America experienced the most severe winter in history and global climate was disrupted for a decade. Millions of people died from the resulting drought and famine. The Laki incident was nonetheless miniscule by comparison with the second Deccan Traps outburst, which produced 1.5 million square kilometers of lava and an estimated 6,500- 17,000 gigatons of sulfur dioxide.
The Deccan Traps eruptions would also have emitted immense quantities of carbon dioxide. Carbon dioxide is a heat trapping greenhouse gas responsible for the oven-like temperatures of the planet Venus. It is released by the burning of fossil fuels and plays a major role in human-caused global warming on Earth. Thus Geller surmised that the Deccan Traps eruptions could have produced both periods of intense cold due to sulfur dioxide haze, and intense heat due to carbon dioxide induced global warming.
At the October conference she presented the results of her studies of geological formations in Tunisia that preserved a high resolution record of climate change during the time of the main pulse of Deccan Traps volcanic activity. Her evidence shows that near the onset of the 250,000 year pulse, there was a ‘hyperthermal’ period of rapid warming that increased ocean temperatures by 3-4 degrees Celsius. She claimed that temperatures remained elevated through the pulse culminating with a second ‘hyperthermal’ warming of the oceans by an additional 4-5 degrees Celsius. This second hyperthermal warming occurred within a 10,000 year period of mega-eruptions, which corresponded with the terminal Cretaceous extinction. The Chicxulub impact occurred during the 250,000 year pulse, but well prior to the extinctions and the hyperthermal event.
The debate over the relative importance of the Chicxulub impact and the Deccan Trap volcanoes in producing the terminal Cretaceous extinction isn’t over. In May of this year, a team headed by Dr. Johan Vellekoop at the Department of Earth Sciences at Ulrecht University in the Netherlands published evidence of a geologically brief episode of cooling which they claim as the first direct evidence of an “impact winter”. Whatever the outcome of the debate, it seems clear that the end of the Cretaceous, with its super-volcanoes and giant impacts, was not a good time for life on Earth.
G. Keller (2012), The Cretaceous-Tertiary Mass Extinction, Chicxulub Impact, and Deccan Volcanism, Earth and Life, J.A. Talent, Editor, Springer Science and Business media.
A close-up of a boulder nicknamed "Cheops" on the surface of 67P/Churyumov-Gerasimenko. Image taken by the Rosetta spacecraft. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
As the Rosetta spacecraft drops a bit closer to its target comet, some really cool features are popping into view. For example, look at this picture of a 150-foot (45-meter) rock on Comet 67P/Churyumov-Gerasimenko, which was taken in September and released today (Oct. 9). And it’s led to the decision to have an Egyptian theme to naming features on the comet.
“It stands out among a group of boulders in the smooth region located on the lower side of 67P/C-G’s larger lobe,” ESA stated in a release. “This cluster of boulders reminded scientists of the famous pyramids at Giza near Cairo in Egypt, and thus it has been named Cheops for the largest of those pyramids, the Great Pyramid, which was built as a tomb for the pharaoh Cheops (also known as Kheops or Khufu) around 2550 BC.”
Scientists are still trying to figure out what the boulders are made of, and how they are formed, as the spacecraft moves into a “close observation phase” tomorrow (Oct. 10) where it is only 10 kilometers (6.2 miles) from the surface.
A wider field of view of 67P/Churyumov-Gerasimenko on the larger lobe, where the boulder Cheops is located. This picture was taken by the Rosetta spacecraft shortly after its arrival in August. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Meanwhile, some new results are coming from an asteroid that the spacecraft whizzed by a couple of years ago. In the picture below, you can see evidence of a crater that Rosetta didn’t even see!
The grooves you see there on Lutetia (which Rosetta imaged in 2010) hint at shock waves from various craters, including one that was likely on the hidden side of the asteroid relative to Rosetta as it flew by. The suspected crater is called “Suspicio.” While craters have been found in other asteroids visited by spacecraft, grooves are rarer.
“The way in which grooves are formed on these bodies is still widely debated, but it likely involves impacts,” ESA stated. “Shock waves from the impact travel through the interior of a small, porous body and fracture the surface to form the grooves.”
A paper on the research will be published in Planetary and Space Science this month, led by Sebastien Besse, a research fellow at ESA’s Technical Centre. For more information, check out this release from ESA.
A part of asteroid Lutetia imaged by the Rosetta spacecraft in 2010. The grooves you see are colored according to the crater scientists believe it’s associated with. The blue lines are from a suspected, unseen crater called “Suspicio”. Red is associated with the known crater Massilia and purple for the North Pole Crater Cluster. Yellow is unassociated with craters considered in this study. Credit: Data: Besse et al (2014); image: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Five orbiters from India, the European Union and the United States will nestle behind the Mars as comet Siding Springs passes at a speed of 200,000 km/hr (125,000 mph). At right, Comet Shoemaker-Levy 9 impacts on Jupiter, the Chelyabinsk Asteroid over Russia. (Credits: NASA,ESA, ISRO)
It was 20 years ago this past July when images of Jupiter being pummeled by a comet caught the world’s attention. Comet Shoemaker-Levy 9 had flown too close to Jupiter. It was captured by the giant planet’s gravity and torn into a string of beads. One by one the comet fragments impacted Jupiter — leaving blemishes on its atmosphere, each several times larger than Earth in size.
Until that event, no one had seen a comet impact a planet. Now, Mars will see a very close passage of the comet Siding Spring on October 19th. When the comet was first discovered, astronomers quickly realized that it was heading straight at Mars. In fact, it appeared it was going to be a bulls-eye hit — except for the margin of error in calculating a comet’s trajectory from 1 billion kilometers (620 million miles, 7 AU) away.
It took several months of analysis for a cataclysmic impact on Mars to be ruled out. So now today, Mars faces just a cosmic close shave. But this comet packs enough energy that an impact would have globally altered Mars’ surface and atmosphere.
So what should we Earthlings gather from this and other events like it? Are we next? Why or why not should we be prepared for impacts from these mile wide objects?
For one, ask any dinosaur and you will have your answer.
An illustration of the Siding Spring comet in comparison to the Comet 67P atop Los Angeles. The original image was the focus of Bob King’s article – “What Comets, Parking Lots and Charcoal Have in Common“. (Credit: ESA, anosmicovni)
One can say that Mars was spared as were the five orbiting spacecraft from India (Mars Orbiter Mission), the European Union (Mars Express) and the United States (MOD, MRO, MAVEN). We have Scottish-Australian astronomer Robert McNaught to thank for discovering the comet on January 3, 2013, using the half meter (20 inch) Uppsala Southern Schmidt Telescope at Siding Spring, Australia.
Initially the margin of error in the trajectory was large, but a series of observations gradually reduced the error. By late summer 2014, Mars was in the clear and astronomers could confidently say the comet would pass close but not impact. Furthermore, as observations accumulated — including estimates of the outpouring of gases and dust — comet Siding Spring shrunk in size, i.e. the estimates of potentially tens of kilometers were down to now 700 meters (4/10th of a mile) in diameter. Estimates of the gas and dust production are low and the size of the tail and coma — the spherical gas cloud surrounding the solid body — are small and only the outer edge of both will interact with Mars’ atmosphere.
The mass, velocity and kinetic energy of celestial bodies can be deceiving. It is useful to compare the Siding Spring comet to common or man-made objects.
Yet, this is a close call for Mars. We could not rule out a collision for over six months. While this comet is small, it is moving relative to Mars at a speed of 200,000 kilometers/hour (125,000 mph, 56 km/sec). This small body packs a wallop. From high school science or intro college Physics, many of us know that the kinetic energy of an object increases by the square of the velocity. Double the velocity and the energy of the object goes up by 4, increase by 3 – energy increases by 9.
So the close shave for Mars is yet another wake up call for the “intelligent” space faring beings of the planet Earth. A wake up call because the close passage of a comet could have just as easily involved Earth. Astronomers would have warned the world of a comet heading straight for us, one that could wipe out 70% of all life as happened 65 million years ago to the dinosaurs. Replace dinosaur with humans and you have the full picture.
Time would have been of the essence. The space faring nations of the world — those of the EU, and Russia, the USA, Japan and others — would have gathered and attempted to conceive some spacecrafts with likely nuclear weapons that could be built and launched within a few months. Probably several vehicles with weapons would be launched at once, leaving Earth as soon as possible. Intercepting a comet or asteroid further out would give the impulse from the explosions more time to push the incoming body away from the Earth.
There is no way that humanity could sit on their collective hands and wait for astronomers to observe and measure for months until they could claim that it would just be a close call for Earth. We could imagine the panic it would cause. Recall the scenes from Carl Sagan’s movie Contact with people of every persuasion expressing at 120 decibels their hopes and fears. Even a small comet or asteroid, only a half kilometer – a third of a mile in diameter would be a cataclysmic event for Mars or Earth.
But yet, in the time that has since transpired from discovery of the comet Siding Spring (1/3/2013), the Chelyabinsk asteroid (~20 m/65 ft) exploded in an air burst that injured 1500 people in Russia. The telescope that discovered Comet Siding Spring was decommissioned in late 2013 and the Southern Near-Earth Object Survey was shutdown. This has left the southern skies without a dedicated telescope for finding near-Earth asteroids. And proposals such as the Sentinel project by the B612 Foundation remain underfunded.
We know of the dangers from small celestial bodies such as comets or asteroids. Government organizations in the United States and groups at the United Nations are discussing plans. There is plenty of time to find and protect the Earth but not necessarily time to waste.
Phobos. From where did it arise or arrive? Is it dry or wet? Should we flyby or sample and return? Should it be Boots or Bots? (Photos: NASA, Illus.:T.Reyes)
Ask any space enthusiast, and almost anyone will say humankind’s ultimate destination is Mars. But NASA is currently gearing up to go to an asteroid. While the space agency says its Asteroid Initiative will help in the eventual goal of putting people on Mars, what if instead of going to an asteroid, we went to Mars’ moon Phobos?
Three prominent planetary scientists have joined forces in a new paper in the journal Planetary and Space Science to explain the case for a mission to the moons of Mars, particularly Phobos.
“Phobos occupies a unique position physically, scientifically, and programmatically on the road to exploration of the solar system,” say the scientists. In addition, the moons may possibly be a source of in situ resources that could support future human exploration in circum-Mars space or on the Martian surface. But a sample return mission first could provide details on the moons’ origins and makeup.
The Martian moons are riddles, wrapped in a mystery, inside an enigma.Phobos and its sibling Deimos seem like just two asteroids which were captured by the planet Mars, and they remain the last objects of the inner solar system not yet studied with a dedicated mission. But should the moons be explored with flybys or sample-return? Should we consider “boots or bots”?
The publications and mission concepts for Phobos and Deimos are numerous and go back decades. The authors of “The Value of a Phobos Sample Return,” Murchie, Britt, and Pieters, explore the full breadth of questions of why and how to explore Phobos and Deimos.
Dr. Murchie is the principal investigator of the Mars Reconnaissance Orbiter’s CRISM instrument, a visible/infrared imaging spectrometer. He is a planetary scientist from John Hopkins’ Applied Physics Lab (APL) which has been at the forefront of efforts to develop a Phobos mission. Likewise, authors Dr. Britt, from the University of Central Florida, and Dr. Pieters, from Brown University, have partnered with APL and JPL in Phobos/Deimos mission proposals.
An MRO HiRise image of the Martian moon Phobos. Taken on March 23, 2008. Phobos has dimensions of 27 × 22 × 18 km, while Deimos is 15 × 12.2 × 11 km. Both were discovered in 1877 at the US Naval Observatory in Washington, D.C. (Photo: NASA/MRO/HiRISE)
APL scientists are not the only ones interested in Phobos or Deimos. The Jet Propulsion Laboratory, Ames Research Center and the SETI Institute have also proposed several missions to the small moons. Every NASA center has been involved at some level.
But the only mission to actually get off the ground is the Russian Space Agency’s Phobos-GRUNT[ref]. The Russian mission was launched November 9, 2011, and two months later took a bath in the Pacific Ocean. The propulsion system failed to execute the burns necessary to escape the Earth’s gravity and instead, its orbit decayed despite weeks of attempts to activate the spacecraft. But that’s a whole other story.
The Russian-led mission Phobos-Grunt did not end well; under Pacific swells to be exact. Undaunted Russian scientists are pressing for Phobos-Grunt 2 (illus.), an improved lander with sample-return. Proposed for 2020s (Credit: CNES)
“The Value of a Phobos Sample Return” first discusses the origins of the moons of Mars. There is no certainty. There is a strong consensus that Earth’s Moon was born from the collision of a Mars-sized object with Earth not long after Earth’s formation. This is just one possibility for the Martian moons. Murchie explains that the impacts that created the large basins and craters on Mars could have spawned Phobos and Deimos: ejecta that achieved orbit, formed a ring and then coalesced into the small bodies. Alternative theories claim that the moons were captured by Mars from either the inner or outer solar system. Or they could have co-accreted with Mars from the Solar Nebula. Murchie and the co-authors describe the difficulties and implications of each scenario. For example, if captured by Mars, then it is difficult to explain how their orbits came to be “near-circular and near-equatorial with synchronous rotational periods.”
To answer the question of origins, the paper turns to the questions of their nature. Murchie explains that the limited compositional knowledge leaves several possibilities for their origins. They seem like D-type asteroids of the outer asteroid belt. However, the moons of Mars are very dry, void of water, at least on their surfaces as the paper discusses in detail. The flybys of Phobos and Deimos by NASA and ESA spacecraft are simply insufficient for drawing any clear picture of their composition or structure, let alone their origins, Murchie and co-authors explain.
If the moons were captured then they have compositions different from Mars; however if they accreted with or from Mars, then they share similar compositions with the early Mars when forming, or from Martian crustal material, respectively.
The paper describes in some detail the problem that billions of years of Martian dust accumulation presents. Every time Mars has been hit by a large asteroid, a cloud of debris is launched into space. Some falls back to the planet but much ends up in orbit. Each time, some of the debris collided with Phobos and Deimos; Murchie uses the term “Witness plate” to describe what the two moons are to Mars. There is an accumulation of Martian material and also material from the impactors covering the surfaces of the moons. Flyby images of Phobos show a reddish surface similar to Mars, and numerous tracks along the surface as if passing objects struck, plowed or rolled along. However, the reddish hue could be weathering from Solar flux over billions of years.
The paper continues with questions of the composition and how rendezvous missions could go further to understanding the moons makeup and origins, however, it is sample return that would deliver, the pay dirt. Despite how well NASA and ESA engineers have worked to shrink and lighten the instruments that fly, orbit, and land on Mars, returning a sample of Phobos to labs on Earth would permit far more detailed analysis.
SpaceX and Elon Musk claim that they will mount human flight to Mars before 2030. Many others remain less optimistic with hopes of human flights before 2040. (Illustrations: Total Recall, 1990, early artist illustration c.1950s )
Science Fiction writers and mission designers have imagined Phobos, in particular, as a starting point for the human exploration and colonization of Mars. A notable contemporary work is “Red Mars” by Kim Stanley Robinson; however, the story line is dated due to the retirement of the Space Shuttle and the external tanks Robinson clustered to form the colonization vessel. While this paper by Murchie et al. is purely scientific, fiction writers have used the understanding that Phobos is far easier to reach from Earth than is the surface of Mars (see Delta-V chart below).
A diagram showing the stair-step energy needed to travel to places beyond the Earth. Delta-V is the speed in km/sec required to reach a destination. As shown, the Delta-Vs are cumulative. Note that it takes an extra 5 km/sec beyond Phobos to reach the Martian surface; a prime reason for making the journey to the moons of Mars. (Credit: Wikipedia, Delta-V)
Phobos, orbiting at 9,400 kilometers (5,840 miles), and Deimos, at 23,500 km (14,600 miles), above Mars avoids the need for the 7-odd minutes of EDL terror – Entry, Descent, and Landing — and pulling oneself out of the Martian gravity well to return to Earth. Furthermore, there is the interest in using Phobos as a material resource – water, material for rocket fuel or building materials. “The Value of a Phobos Sample Return” discusses the potential of Phobos as a resource for space travelers – “In Situ Resource Utilization” (ISRU), in the context of its composition, how the solar flux may have purged the moons of water or how Martian impact debris covers materials of greater interest and value to explorers.
With so many questions and interests, what missions have been proposed and explored? The Murchie paper describes a half dozen missions but there are several others that have been conceived and proposed to some level over several decades.
At present, there is at least one mission actively pursuing funds. The SETI and Ames proposed “Phobos and Deimos & Mars Environment” (PADME) mission led by Dr. Pascal Lee is competing for Discovery program funding. Such projects must limit cost to $425 million or less and be capable of launching in less than 3 years. They are proposing a launch date of 2018 on a SpaceX Falcon 9. The PADME mission design would reuse Ames LADEE hardware and expertise, however, it does not go so far as what Murchie and co-authors argue – returning a sample from Phobos. PADME would maintain in a synchronized orbit with Phobos and then Deimos foe repeated flybys. The mission is likely to cost in the range of $300 million. Stardust, a relevant mission due to its sample return capsule, launched in 1999 and had costs which likely reached a similar level by end of mission in 2012.
The Russian Space Agency is attempting to gain funding for Phobos-Grunt 2 but possible launch dates continue to be moved back – 2020, 2022, and now possibly 2024.
Return of the Stardust sample inside the Lockheed-Martin developed sample-return capsule. Seen here upon successful landing in the Utah desert. (Credit: NASA/Stardust)
Additionally, each of this papers’ authors has mission proposals described. Dr. Pieters, JPL, and Lockheed-Martin proposed the Aladdin mission; Dr. Britt at APL, also with Lockheed-Martin, proposed the mission Gulliver; both would re-use the Stardust sample-return capsule (photo, above). Dr. Murchie also describes his APL/JPL mission concept called MERLIN (Mars–Moon Exploration, Reconnaissance and Landed Investigation).
Phobos and Deimos are the last two of what one would call major objects of the inner Solar System that have not had dedicated missions of exploration. Several bodies of the Asteroid Belt have been targeted with flybys and Dawn is nearing its second target, the largest of the Asteroids, Ceres.
So sooner rather than later, a spacecraft from some nation (not necessarily the United States) will target the moons of Mars. Targeted Phobos/Deimos missions are also likely to include both flyby missions and one or more sample-return missions. A US-led mission with sample-return in the Discovery program will be strained to meet both criteria – $425 million cost cap and 3 year development period.
Those utilizing the Lockheed-Martin (LM) Stardust design have a proven return capsule and spacecraft buses (structure, mechanisms and avionics) for re-use for cost and time savings. This includes five generations of the LM flight software that holds an incredible legacy of mission successes starting with Mars Odyssey/Genesis/Spitzer to now Maven.
All three proposals by this paper’s authors could be re-vamped and proposed again and compete against each other. All three could use Lockheed-Martin past designs. Cooperation in writing this paper may be an indicator that they will join forces, combine concepts, and share investigator positions on a single NASA-led project. The struggle for federal dollars remains a tough, tight battle and with the human spaceflight program struggling to gain a new footing after Space Shuttle, dollars for inter-planetary missions are likely to remain very competitive. However, it appears a Phobos-Deimos mission is likely within the next ten years.
Looking to the future of space exploration, NASA and TopCoder have launched the "High Performance Fast Computing Challenge" to improve the performance of their Pleiades supercomputer. Credit: NASA/MSFC
TORONTO, CANADA – Could NASA’s new rocket bring a probe to sample the geysers of Saturn’s moon Enceladus, or ferry human explorers to the surface of Mars? Representatives of contractor Boeing think so.
They’ve put together some ideas for sending their Space Launch System to these far-flung destinations, which they presented at the International Astronautical Congress today (Oct. 1).
Bear in mind that the SLS hasn’t yet flown — it’s slated for 2018 if funding lasts and the schedule holds — and the destinations below are just in the conceptual stage. The gallery below summarizes some of the destinations SLS could visit. For more information, check out this brochure by Boeing.
Enceladus
Artist’s conception of the Cassini spacecraft flying amid geysers on Enceladus, a moon of Saturn. Credit: Karl Kofoed / NASA
The icy moon of Saturn is known as a hotspot for geysers; earlier this year, scientists found 101 gushers using data from the prolific Cassini probe. Using the SLS could bring a satellite there in four years, as opposed to about seven with rockets on the market today, according to Boeing. It also could carry a heavier spacecraft.
Europa
Artist’s conception of Europa’s surface, backdropped by planet Jupiter. Credit: NASA/JPL-Caltech
Europa is known to have a subterranean ocean, and it also is capable of spewing water plumes — as researchers using the Hubble Space Telescope discovered earlier this year. The SLS could get to Europa a lot faster than a launch with an Atlas, according to Boeing — it would only take two years to fly there directly as opposed to more than six years with the Atlas, which would need to fly by Venus first to pick up some speed.
Trojan asteroids
Artist’s diagram of Jupiter and some Trojan asteroids nearby the gas giant. Credit: NASA/JPL-Caltech
Trailing before and after Jupiter are more than a million asteroids that are called Trojans. This means any probe in the area would have no lack of targets to study, providing it had enough fuel on board. A mission profile from Boeing suggests the SLS could bring a spacecraft out there that could swing by a target at least half a dozen times.
Mars
Artist’s impression of astronauts exploring Mars. Credit: NASA/Pat Rawlings, SAIC
One of the largest challenges of getting to Mars is figuring out how to send all the life-support equipment and food that humans require — on top of the humans themselves! Since SLS is a heavy-lift rocket, Boeing is trying to position its rocket as the ideal one to get humans to Mars. But it remains to be seen what concept works best to get people out there.
The Moon
Artist’s impression of astronauts on the moon. This image was used to illustrate a landing concept of NASA’s now defunct Constellation program. Credit: John Frassanito and Associates / NASA
Boeing has an idea to bring a lander down to the Moon that could then lift off multiple times in search of other destinations. Such a concept would require a hefty amount of fuel and equipment. If it works, Boeing says the SLS could assist with plans for lunar mining and other exploration ideas.
The suspect crater on the outskirts of Managua. Credit: AP/BBC News
By now, you’ve seen the pictures.
As astronomers tracked the close pass of Near Earth Asteroid 2014 RC this weekend, reports came out of Nicaragua that a possible meteorite struck near the capital of Managua.
Details are still sketchy, but government sources cite reports of a loud bang and ground tremor late Saturday night on September 6th. Later images circulating late Sunday evening showed a crater 12 metres wide and 5.5 metres deep on a remote section of the international airport at Managua, which also hosts a local air force installation.
A closer look at the Managua crater. Credit: AFP/BBC News.
Reports state that the impact went off “like a bomb,” and Wilfried Strauch of the Nicaragua Institute of Earth Studies has already gone on record as being “convinced it was a meteorite.” Investigators are currently scouring the alleged impact site for debris.
This has also sparked a lively discussion across forums and social media: is the crater the result of an extraterrestrial impactor?
Of course, cosmic coincidences can and do happen. Last year, the close passage of asteroid 2012 DA14 was upstaged by the explosion of a 20-metre asteroid over the city of Chelyabinsk on the very same day. And though the two were conclusively proven to be unrelated, they did serve to raise general human awareness that, yes, large threatening rocks do indeed menace the Earth. And ironically, the aforementioned asteroid 2014 RC was about the same size as the Chelyabinsk asteroid, which snuck up on the Earth undetected from a sunward direction.
But Ron Baalke, a software engineer at the Jet Propulsion Laboratory has posted an update to the close pass by asteroid 2014 RC on the NASA’s Near Earth Object website, saying, “Since the explosion in Nicaragua occurred a full 13 hours before the close passage of asteroid 2014 RC, these two events are unrelated.”
Baalke also noted that “no eyewitness accounts or imagery have come to light of the fireball flash or debris trail that is typically associated with a meteor of the size required to produce such a crater.”
The epic airburst over Chelyabinsk as captured via dashcam. (Still from video).
There are a few other problems with the Managua crater, though of course, we’d love to be proven wrong. Many observers have noted that the crater does not appear to look fresh, and the trees and soil around it appear to be relatively undisturbed. A first visual impression of the site looks more like a ground slump or sinkhole than an impact, or perhaps an excavation. Others have also noted the similarity of the crater with a military blast, a very good possibility with an air force base nearby.
Meteorite Men’s own Geoff Notkin has voiced doubts as to the authenticity of the meteor crater on Twitter.
Of course, it’s possible (though unlikely) that the impactor struck the site from straight overhead, leaving the area around it undisturbed. As with meteor showers, an impactor striking the Earth before local midnight would be coming at the planet from behind at a lower combined velocity.
Color me skeptical on this one. Still, we’ve been wrong before, and it’s always a boon for science when a new meteorite fall turns out to be real. Many have already cited the similarities between the Managua crater and the Carancas event in 2007 in Peru near Lake Titicaca that was initially considered dubious as well.
But again, it’s highly improbable that the Managua event is related to 2014 RC, however, which made its closest pass over the southern hemisphere near New Zealand many hours later at 18:18 UT on Sept 7th. We ran a recent simulation of the pass in Starry Night from the vantage point of the asteroid, and you’ll note that Central America is well out of view:
It’s also curious that no still images or video of the Managua event have yet to surface. This is strange, as it occurred on a Saturday night near a capital city of 2.4 million. The weather over Managua was partly cloudy that night, and generally, a security camera or two usually catches sight of the fireball.
We also did a check through any upcoming space junk reentries, which also proved to be a poor fit for a potential suspect. The next slated reentry is a BREEZE-M Tank with the NORAD ID of 2011-074D associated with the 2011 launch of AMOS-5. This object was not overhead around the time of the Managua event, and is predicted to reenter on September 9th at 15:15 UT +/- 14 hours.
And the same goes for the launch of AsiaSat-6 by SpaceX on Saturday night, as launches from the Cape head out eastward across the Atlantic and away from the Gulf of Mexico region.
A look at 2014 RC on the night of September 6th. Credit: Gianluca Masi and the Virtual Telescope Project.
Unfortunately, images and video would go a long way towards gauging a direction and final orbit of a suspect meteorite. The discovery of meteoritic debris at the site would also serve to clinch the link between the crater and a cosmic impactor as well. Or perhaps, news of the impending passage of NEO asteroid 2014 RC and the recent pass of 2014 RA the weekend prior had already primed the general public to suspect a meteor strike as an explosion was heard late in the evening… we’ve lived near bombing ranges, and are familiar with the sound of late night explosions ourselves.
Target Earth… An aerial view of Pingualuit crater in northern Quebec. Credit: NASA/Denis Sarrazin and the Pingualuit Crater Lakes project.
To be sure, the universe is a dangerous place, and errant rocks from above do on occasion have it out for any unwary species that gets in their way.
So we’ll open it up for discussion: what do you think happened on Saturday night near Managua? Was it a meteorite, or another case of a “meteor-wrong?”
Asteroid 2014 RC photographed 30 minutes before closest approach to Earth today. During this one-minute-long time exposure the asteroid covered more than 3/4 degree of sky. Credit: Ernesto Guido, Nick Howes, Martino Nicolini
Earth-approaching asteroid 2014 RC ripped pass Earth today, got its orbit refashioned by our planet’s gravity and now bids us adieu. I thought you’d like to see how fast this ~60-foot-wide (20-meter) space rock moved across the sky. The team of observers at Remanzacco Observatory in Italy photographed it remotely with a telescope set up in Australia. 30 minutes before closest approach to Earth of 25,000 miles (40,000 km), 2014 RC was traveling at the rate of 49.5 arc minutes (1.6 times the diameter of the full moon) per minute.
2014 RC accelerates across the sky from 4 a.m. to 4 p.m EDT in this path created by Gianluca Masi using SkyX Pro software and the latest positions from JPL. he asteroid’s intrinsic speed was not exceptional, but because it came so close to Earth, it covered a huge swath of sky in a hurry.
At the time, the asteroid glowed at magnitude +11.2, bright enough to see in a 4.5 inch telescope even in the bright moonlit sky at the time. Let’s try to get a feel for its speed. Just to keep 2014 RC centered in the field of view, you’d have to continually move the telescope to follow it as it you were tracking an airplane or satellite. What a thrill it must have been for observers in Australia and New Zealand who got the ride of their life across the heavens hanging onto this fleet rock with their eyeballs. In an hour’s time, centered on closest approach, the asteroid traveled approximately 48º. That more than twice the length of the constellation Orion!
The orbit of 2014 RC occasionally brings it close to Earth as it did today September 7, 2014 when it passed less than 1/10 the distance of the moon to the Earth. The asteroid orbits the sun every 1.5 years. Credit: NASA/JPL-Caltech
As 2014 RC blew by, its orbit was bent by Earth’s gravity and sent on a new trajectory. If this sounds familiar, we deliberately performed the same maneuver with the Voyager I and II spacecraft back in the late 1970s and early 1980s. A rare planetary alignment allowed scientists to swing the probes near Jupiter and Saturn to gain speed and shape their orbits for future encounters. Such gravity assist maneuvers are now commonplace.
Space rock exposed! Gianluca Masi, who runs the Virtual Telescope Project, tracked 2014 RC during his time exposure, so it shows up as a tiny dot instead of a streak. Credit: Gianluca Masi
No doubt 2014 RC will approach Earth again, but no threatening encounters are in the cards for at least 100 years. For now we’re grateful it passed safely while inspiring wonder at what the solar system can throw at us.
