Image of Io taken in the near-infrared with adaptive optics at the Gemini North telescope on August 29. In addition to the extremely bright eruption on the upper right limb of the satellite, the lava lake Loki is visible in the middle of Io’s disk, as well as the fading eruption that was detected earlier in the month by de Pater on the southern (bottom) limb. Io is about one arcsecond across. Image credit: Katherine de Kleer/UC Berkeley/Gemini Observatory/AURA
Jupiter’s innermost moon, Io — with over 400 active volcanoes, extensive lava flows and floodplains of liquid rock — is by far the most geologically active body in the Solar System. But last August, Io truly came alive with volcanism.
Three massive volcanic eruptions led astronomers to speculate that these presumed rare outbursts were much more common than previously thought. Now, an image from the Gemini Observatory captures what is one of the brightest volcanoes ever seen in our Solar System.
“We typically expect one huge outburst every one or two years, and they’re usually not this bright,” said lead author Imke de Pater from the University of California, Berkeley, in a press release. In fact, only 13 large eruptions were observed between 1978 and 2006. “Here we had three extremely bright outbursts, which suggest that if we looked more frequently we might see many more of them on Io.”
De Pater discovered the first two eruptions on August 15, 2013, from the W. M. Keck Observatory in Hawaii. The brightest was calculated to have produced a 50 square-mile, 30-feet thick lava flow, while the other produced flows covering 120 square miles. Both were nearly gone when imaged days later.
The third and even brighter eruption was discovered on August 29, 2013, at the Gemini observatory by UC Berkeley graduate student Katherine de Kleer. It was the first of a series of observations monitoring Io.
Images of Io tracking the evolution of the eruption as it decreased in intensity over 12 days. Due to Io’s rapid rotation, a different area of the surface is viewed on each night; the outburst is visible with diminishing brightness on August 29 & 30 and September 1, 3, & 10. Image credit: Katherine de Kleer / UC Berkeley / Gemini Observatory / AURA
This allowed the observations to “represent the best day-by-day coverage of such an eruption,” said de Kleer. The team was able to conclude that the energy emitted from the late-August eruption was about 20 Terawatts, and expelled many cubic kilometers of lava.
“At the time we observed the event, an area of newly-exposed lava on the order of tens of square kilometers was visible,” said de Kleer. “We believe that it erupted in fountains from long fissures on Io’s surface, which were over ten-thousand-times more powerful than the lava fountains during the 2010 eruption of Eyjafjallajokull, Iceland, for example.”
The team hopes that monitoring Io’s surface annually will reveal the style of volcanic eruptions on the moon, the composition of the magma, and the spatial distribution of the heat flows. The eruptions may also shed light on an early Earth, when heat from the decay of radioactive elements — as opposed to the tidal forces influencing Io — created exotic, high-temperature lavas.
“We are using Io as a volcanic laboratory, where we can look back into the past of the terrestrial planets to get a better understanding of how these large eruptions took place, and how fast and how long they lasted,” said coauthor Ashley Davies.
The latest results have been published in the journal Icarus.
LDN 673, a molecular cloud complex in the constellation Aquila. Credit and copyright: Callum Hayton.
What a stunning view of this dark region of space! This image, by astrophotographer Callum Hayton shows LDN 673, a molecular cloud complex that lies in the constellation Aquila. This region is massive — around 67 trillion kilometers (42 trillion miles across), and it is between 300-600 light years from Earth. Observers in the northern hemisphere can find this region in the summer skies near the bright star Altair and the Summer Triangle.
Because the cloud lies on the galactic plane, the dark dust is back-lit by millions of stars in the Milky Way galaxy. This dusty cloud likely contains enough raw material to form hundreds of thousands of stars. Hayton explained on Flickr how the dust gets “eroded” away by stellar formation:
“When some of these clouds reach a certain mass they begin to collapse and fragment creating protostars,” Hayton wrote. “As the temperature and pressure at the centre of the protostar rises, sometimes it becomes so great that nuclear fusion begins and a star is born. In this image you can see where at least two young stars have eroded the dust around them and are now above the clouds casting light down on to the dust below.”
Gorgeous!
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The July 2014 Supermoon rising over the University of Texas at Austin Tower. Credit: Mark Ezell, used with permission.
You could be forgiven for thinking this summer that the “supermoon” is now a monthly occurrence. But this coming weekend’s Full Moon is indeed (we swear) the closest to Earth for 2014.
What’s going on here? Well, as we wrote one synodic month ago — the time it takes for the Moon to return to the same phase at 29.5 days — we’re currently in a cycle of supermoons this summer. That is, a supermoon as reckoned as when the Full Moon falls within 24 hours of perigee, a much handier definition than the nebulous “falls within 90% of its orbit” proposed and popularized by astrologers.
A super-sized shot of the July 2014 supermoon. Credit: Russell Bateman.
The supermoons for 2014 fall on July 13th, August 10th and September 8th respectively. You could say that this weekend’s supermoon is act two in a three act movement, a sort of Empire Strikes Back to last month’s A New Hope.
Now for the specifics: Full Moon this weekend occurs on August 10th at 18:10 Universal Time (UT) or 2:10 PM EDT. The Moon will reach perigee or its closest point to the Earth at 17:44 UT/1:44 PM EDT just 26 minutes prior to Full, at 55.96 Earth radii distant or 356,896 kilometres away. This is just under 500 kilometres shy of the closest perigee that can occur at 356,400 kilometres distant. Perigee was closer to Full phase time-wise last year on June 23rd, 2013, but this value won’t be topped or tied again until November 25th, 2034. The Moon will be at the zenith and closest to the surface of the Earth at the moment it passes Full over the mid-Indian Ocean on Sunday evening nearing local midnight.
The 99.8% Full Moon from July 2014. Credit: Stephen Rahn.
Now for a reality check: The August lunar perigee only beats out the January 1st approach of the Moon for the closest of 2014 by a scant 25 kilometres. Perigees routinely happen whether the Moon is Full or not, and they occur once every anomalistic month, which is the average span from perigee-to-perigee at 27.6 days. This difference between the anomalistic and synodic period causes the coincidence that is the supermoon to precess forward about a month a year. You can see our list of supermoon seasons out until 2020 here.
A comparison of lunar distance (dark line) with phase (grey line) for 2014. Note that 0.5 denotes Full, while 0 denotes New phase. Credit: Darekk2, Wikimedia Commons graphic under a 3.0 Unported license.
And don’t forget, the Moon actually approaches you to the tune of about half of the radius of the Earth while it rises to the zenith, only to recede again as it sinks back down to the horizon. The rising Full Moon on the horizon only appears larger mainly due to an illusion known as the Ponzo Effect.
The apparent size of the Moon varies about 14% in angular diameter from 29.3′ (known as an apogee “mini-Moon”) to 34.1′ at its most perigee “super-size” as seen from the Earth.
The July 2014 supermoon on the rise. Credit: Brad Timerson @btimerson.
Astronomers prefer the use of the term Perigee Full Moon, but the supermoon meme has taken on a cyber-life of its own. Of course, we’ve gone on record before and stated that we prefer the more archaic term Proxigean Moon, but the supermoon seems here to stay.
And as with many Full Moon myths, this week’s supermoon will be implicated in everything from earthquakes to lost car keys to other terrestrial woes, though of course no such links exist. Coworkers/family members/strangers on Twitter will once again insist it was “the biggest ever,” and claim it took up “half the sky” as they unwittingly take part in an impromptu psychological perception test.
The July supermoon shot through a blue filter… I wonder just how rare a “Super-Blue Moon” might be? Credit: Talia Landman @taliaeliana.
Fun fact: you could ring local the horizon with 633 supermoons!
And of course, many a website will recycle their supermoon posts, though of course not here at Universe Today, as we bake our science fresh daily.
So what can you expect? Well, a perigee Full Moon can make for higher than usual tides. New York City residents had the bad fortune of a Full Moon tidal surge in 2012 when Hurricane Sandy made landfall. Though there doesn’t seem to be a chance for a repeat of such an occurrence in 2014 in the Atlantic, super-typhoon Halong is churning towards the Japanese coastline for landfall this weekend…
The rising Waxing Gibbous Moon on the evening of August 9th. Credit: Stellarium.
Observationally, Full Moon is actually a lousy time for astronomical observations, causing many a deep sky astrophotographer to instead stay home and visit the family, while lurking astrophotography forums and debunking YouTube UFO videos.
Pro-tip: want your supermoon photo/video to go viral? Shoot the rising Moon just the evening prior when it’s waxing gibbous but nearly Full. Not only will it be more likely to be picked up while everyone is focused on supermoon lunacy, but you’ll also have the added bonus of catching the Moon silhouetted against a low-contrast dusk sky. We have a pre-supermoon rising video from a few years back that still trends with each synodic period!
Well, that’s it ‘til September, when it’ll be The Return (Revenge?) of the Supermoon. Be sure to send those pics in to Universe Today’s Flickr forum, you just might make the supermoon roundup!
Artist's concept of OSIRIS-REx at Bennu. (Credit: NASA/GSFC)
I love anything that attempts to provide a sense of scale about the Solar System (see here and here for even more examples) and this one brings us down past the Sun, planets, and moons all the way to asteroid size — specifically asteroid 101955 Bennu, the target of the upcoming OSIRIS-REx mission.
Created by the OSIRIS-REx “321Science!” team, consisting of communicators, film and graphic arts students, teens, scientists, and engineers, the video shows some relative scales of our planet compared to the Sun, and also the actual size of asteroid Bennu in relation to some familiar human-made structures that we’re familiar with. (My personal take-away from this: Bennu — one of those “half grains of sand” — is a rather small target!)
A NASA New Frontiers mission, OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) will launch in Sept. 2016 on a two-year journey to the asteroid 101955 Bennu. Upon arrival OSIRIS-REx will map Bennu’s surface and also measure the Yarkovsky effect, by which asteroids’ trajectories can change over time due to the small force exerted by radiant heat.
Artist's impression of the New Horizons spacecraft. Image Credit: NASA
This fall, Universe Today plans to get in-depth into the Pluto planethood debate. I (Elizabeth Howell) just launched a crowdfunding project on a new platform called Beacon that will allow me to fly down to Washington, D.C. for several days to interview Pluto scientists.
Should the project be funded, a few fun things are going to happen. Here, Universe Today readers will get a series of articles into the Pluto planethood debate. We’ll examine the controversial International Astronomical Union vote and why certain scientists still don’t believe Pluto is a dwarf planet today.
The question has special relevance today because NASA’s New Horizons spacecraft is on a journey to Pluto, and is less than a year from getting there. Examining Pluto will give scientists a window into how the solar system formed, which in turn gives us clues as to how the Earth came to be. We’ll have some stuff about the science as well; stay tuned for the details!
You’ll also get the chance to support astronomy education and outreach. I’m pleased to announce that CosmoQuest will be a partner on the project, receiving 15% of all proceeds for the project. If you contribute $250, $500 or $1,000, they will receive an additional 15% of your money. Contributors at this level will have their name mentioned in at least two of a series of six podcasts I will do for CosmoQuest’s 365 Days of Astronomy. There are other fun perks, too, so check out the Beacon page for more.
As a freelance journalist, my challenge with doing travel stories is I have to pay my own way. Beacon solves that problem. It will allow me to spend a few days in person with scientists, gathering pictures and videos and podcasts, instead of relying on the phone interviews I usually conduct.
After paying contributions to CosmoQuest and to Beacon, every single cent remaining will be for travel expenses only. The money will give me a flight to Washington, D.C., a few nights in a reasonable hotel, and a car rental. I promise you that I’m extremely frugal — ask my mortgage broker — and I will spend every dollar of your contributions wisely. Additional money after $2,400 will allow me to draw a salary for the days I am there. If a substantial amount of extra money is raised, I’ll consider a second trip to D.C.
A NASA “poster” marking the one year to Pluto encounter by New Horizons. Credit: NASA
I’m not one to brag about my experience, but I will say that I’ve been proudly writing about space for a decade for many publications (including Universe Today). I’m one of the few journalists in Canada to focus on space virtually full-time. And I have covered some fun stories, such as three shuttle launches (2009-10), Chris Hadfield’s last mission (2012-13) and participating in a simulated Mars mission in Utah (early 2014). I see space as a field where I can always learn more, and this will be a great chance to share what I learn about Pluto with you.
Any questions? Feel free to get in touch with me at contact AT elizabethhowell DOT ca or to leave comments below. I likely won’t be able to respond until tomorrow as this launch coincidentally falls on a planned vacation day for me, but I promise that for the rest of the campaign I’ll answer your queries as fast as I can.
A meteor streaks through the sky over Sequoia and Kings Canyon National Parks in California. Credit and copyright: Gavin Heffernan/Sunchaser Pictures.
Shooting the night sky from an area filled with canyons and towering trees might sound like a challenge, but Gavin Heffernan and his crew at Sunchaser Pictures have “majestically” succeeded with this new timelapse from Kings Canyon and Sequoia National Parks in California. They spent three days and two nights around the summer solstice, covering the 1,353 square miles of the two parks. They captured gorgeous night sky views, star trails, bright meteor streaks, and satellite passes — all framed by the magnificent landscape of the area.
“It was undoubtedly one of the most beautiful places I’ve ever seen, with incredible canyons, mountains, and vistas out of a fantasy novel,” Gavin told UT via email. “Far removed from any light pollution, the skies were equally stunning, with some epic milky ways, star trails, and the brightest meteor picture I’ve ever captured.” Image above — and see the new timelapse video below, with the meteor trails coming at 1:41 & 2:26:
Gavin said most night shots were captured with 25 second exposures on two Canon EOS 6D’s with a variety of wide, fast lenses, including a 24mm f1/4 and 28mm f1/8. The stunning star trails effect is created by tracing rotations of the Earth’s axis, using long exposures.
Star trails at dawn just as the Sun rises above the mountains in Kings Canyon. Credit and copyright: Gavin Heffernan.
Find out more about this video on Vimeo and you can watch a “behind the scenes” video of what it took to make this video — including an encounter with a brown bear! — here.
NAVCAM camera image taken on 2 August 2014 from a distance of about 500 kilometers from comet 67P/Churyumov-Gerasimenko. Credits: ESA/Rosetta/NAVCAM
The Rosetta comet chaser is currently less than 500 kilometers (300 miles) from its target destination, Comet 67P/Churyumov-Gerasimenko following today’s (Aug. 3) successful completion of the spacecraft’s critically important penultimate trajectory burn, just three days before its history making arrival at the comet on Aug. 6.
The European Space Agency’s (ESA) 1.3 Billion euro Rosetta spacecraft is now under three days away from becoming Earth’s first probe ever to rendezvous with and enter orbit around a comet after a decade long hunt of 6.4 billion kilometers (4 Billion miles) through interplanetary space. The gap is narrowing with each passing second.
The last trajectory firing is set for Aug. 6. Altogether the final pair of trajectory burns will reduce the spacecrafts speed by some 3.5 meters per second (m/s) with respect to the comet which is traveling at 55,000 kilometers per hour (kph).
The probes latest Navcam camera image shot on Aug. 2, 2014 from a distance of about 500 kilometers from comet 67P/Churyumov-Gerasimenko shows exquisite detail of the rubber ducky shaped body tumbling end over end. See above.
See below our mosaic of navcam camera approach images of the nucleus captured over the past week and a half of the mysterious two lobed comet, merged at a bright band in between.
ESA’s Rosetta Spacecraft nears final approach to Comet 67P/Churyumov-Gerasimenko in late July 2014. This collage of imagery from Rosetta combines Navcam camera images at right taken nearing final approach from July 25 (3000 km distant) to July 31, 2014 (1327 km distant), with OSIRIS wide angle camera image at left of comet’s expanding coma cloud on July 25. Images to scale and contrast enhanced to show further detail.
Credit: ESA/Rosetta/NAVCAM/OSIRIS/MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA Collage/Processing: Marco Di Lorenzo/Ken Kremer
In November 2014, the Rosetta mothership will attempt another historic first when it deploys the Philae science lander from an altitude of just 1 or 2 kilometers for the first ever attempt to land on a comet’s nucleus. The lander will fire harpoons to anchor itself to the 4 kilometer wide (2.5 mile) comet’s surface.
Together, Rosetta and Philae will investigate how the pristine frozen comet composed of ice and rock is transformed by the warmth of the Sun. They will also search for organic molecules, nucleic acids and amino acids, the building blocks for life as we know it.
Did life on Earth begin with the help of comet seeding? That’s a question the Rosetta science team seeks to help answer.
Today’s early morning thruster firing, officially known as the Close Approach Trajectory – pre-Insertion (CATP) burn, began as scheduled at 11:00 CEST (09:00 GMT) and was due to last for about 13 minutes and 12 seconds and bleed off some 3.2 m/s of spacecraft speed.
Although it ended a few seconds early, ESA reports that the CATP burn went well as engineers monitored the spacecraft communications at the European Space Operations Centre (ESOC), in Darmstadt, Germany via the agency’s 35 meter deep-space tracking station in New Norcia, Australia.
“All looks good,” says Rosetta Spacecraft Operations Manager Sylvain Lodiot, according to an ESA operations tweet.
CATP is part of the final series of ten orbit correction maneuvers (OCM’s) that culminates with the final thruster firing slated for Aug. 6 dubbed the Close Approach Trajectory – Insertion (CATI) burn.
“The CATI burn will reduce the relative velocity to about 1 m/s,” says Lodiot. That’s about equivalent to human walking speed.
The CATI orbit insertion firing will slow Rosetta to essentially the same speed as a comet and place it in orbit at an initial stand-off distance of about 100 kilometers (62 miles).
Rosetta will initially be travelling in a series of 100 kilometer-long triangular arcs while firings thrusters at each apex. Further engine firings will gradually lower Rosetta’s altitude about Comet 67P until the spacecraft is captured by the comet’s gravity.
After catching up with the comet Rosetta will slightly overtake and enter orbit from the ‘front’ of the comet as both the spacecraft and 67P/CG move along their orbits around the Sun. Rosetta will carry out a complex series of manoeuvres to reduce the separation between the spacecraft and comet from around 100 km to 25-30 km. From this close orbit, detailed mapping will allow scientists to determine the landing site for the mission’s Philae lander. Immediately prior to the deployment of Philae in November, Rosetta will come to within just 2.5 km of the comet’s nucleus. This animation is not to scale; Rosetta’s solar arrays span 32 m, and the comet is approximately 4 km wide. Credit: ESA–C. Carreau
“All systems on the spacecraft are performing well and the entire team is looking forward to a smooth arrival,” says Lodiot.
It will study and map the wanderer composed of primordial ice, rock, dust and more and search for a suitable landing site for Philae.
The one-way signal time from Earth to Rosetta and Comet 67P is currently 22 minutes and 27 seconds as both loop around the Sun at a distance of some 555 million kilometres away from the Sun at this time. The short period comet is located between the orbits of Jupiter and Mars.
Rosetta will escort Comet 67P as they journey together inwards around the sun and then travel back out towards Jupiter’s orbit and investigate the physical properties and chemical composition of the comets nucleus and coma of ice and dust for some 17 months.
ESA’s Rosetta Spacecraft nears final approach to Comet 67P/Churyumov-Gerasimenko in late July 2014. This collage of imagery from Rosetta combines Navcam camera images at right taken nearing final approach from July 25 (3000 km distant) to July 31, 2014 (1327 km distant), with negative OSIRIS wide angle camera image at left of comet’s expanding coma cloud on July 25. Images to scale and contrast enhanced to show further detail. Credit: ESA/Rosetta/NAVCAM/OSIRIS/MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA Collage/Processing: Marco Di Lorenzo/Ken Kremer
Rosetta was launched on 2 March 2004 on an Ariane 5 G+ rocket from Europe’s spaceport in Kourou, French Guiana.
You can watch Rosetta’s Aug. 6 orbital arrival live from 10:45-11:45 CEST via a livestream transmission from ESA’s spacecraft operations centre in Darmstadt, Germany.
Stay tuned here for Ken’s continuing Rosetta, Curiosity, Opportunity, Orion, SpaceX, Boeing, Orbital Sciences, commercial space, MAVEN, MOM, Mars and more Earth and Planetary science and human spaceflight news.
Ranger 7 took this image, the first picture of the Moon by a U.S. spacecraft, on 31 July 1964 at 13:09 UT (9:09 AM EDT) about 17 minutes before impacting the lunar surface. Credit: NASA/JPL-Caltech
As we remember the 45th anniversary of Earth’s historic 1st manned lunar landing last week by America’s Apollo 11 crew of Neil Armstrong and Buzz Aldrin on July 20, 1969, it’s likewise well worth recalling NASA’s pioneering and historic unmanned robotic mission Ranger 7 – that led the way to the Moon almost exactly 5 years earlier and that paved the path for the eventual 1st human footsteps on another celestial body.
Indeed the first critical robotic step to the manned landings was successfully taken when NASA’s unmanned Ranger 7 probe captured the first image of the Moon by a U.S. spacecraft 50 Years ago on July 31, 1964.
Ranger 7 took the milestone maiden picture of the Moon by an American spacecraft, on 31 July 1964, shown above, at 13:09 GMT (9:09 AM EDT) about 17 minutes before impacting the lunar surface on a suicide dive.
The history making image was taken at an altitude of 2110 kilometers and is centered at 13 S, 10 W and covers about 360 kilometers from top to bottom. The large Alphonsus crater is at center right and 108 km in diameter. Ptolemaeus crater is above and Arzachel is below.
Ranger 7 impacted out of view of the lead image, off to the left of the upper left corner.
“It looks as though this particular shot has been indeed a textbook operation,” William H. Pickering, the director of JPL during the mission, said at the time.
Guericke Crater as seen by Ranger 7
Ranger 7 B-camera image of Guericke crater (11.5 S, 14.1 W, diameter 63 km) taken from a distance of 1335 km. The dark flat floor of Mare Nubium dominates most of the image, which was taken 8.5 minutes before Ranger 7 impacted the Moon on 31 July 1964. The frame is about 230 km across and north is at 12:30. The impact site is off the frame to the left. Credit: NASA/JPL-Caltech
The purpose of NASA’s robotic Ranger program was to take high-quality pictures of the Moon and transmit them back to Earth in real time before being decimated on impact.
NASA Ranger 7 spacecraft. Credit: NASA/JPL-Caltech
The priceless pictures would be used for science investigations as well as to search for suitable landing sites for NASA’s then planned Apollo manned Moon landers.
It’s hard to conceive now, but 5 decades ago at the dawn of the Space Age no one knew what the surface of the Moon was really like. There were vigorous debates back then on whether it was even hard or soft. Was it firm? Would a landed spacecraft or human astronaut sink?
Last Ranger 7 images taken before impact on the Moon. They were taken by the number 1 and 3 P-channel cameras at 0.39 and 0.19 s before impact from an altitude of 1070 and 519 meters, respectively. The pictures are cut off because the spacecraft impacted the surface before completing the transmission. The top image was taken by the P3 camera and the bottom image by P1. The P3 image is about 25 m across. North is at 12:30 for both images. The impact occurred on 31 July 1964 at 13:25:48.82 UT. Credit: NASA/JPL-Caltech
Altogether the probe took 4,308 excellent quality pictures during its final 17 minutes before crashing into the Moon at 13:26 GMT (9:26 p.m. EDT) in an area between Mare Nubium and Oceanus Procellarum at a spot subsequently named Mare Cognitum at 10.63 S latitude, 20.60 W longitude.
The final image from Ranger 7 shown herein had a resolution of 0.5 meter/pixel.
Ranger 7 was launched atop an Atlas Agena B rocket on 28 July 1964 from what was then known as Cape Kennedy and smashed into our nearest neighbor after 68.6 hours of flight at a velocity of 2.62 km/s (1.62 miles per second).
The 365.7 kilogram (806 lb) vehicle was 4.5 m wide and stood 3.6 m (11 ft) tall and was the Block 3 version of the Ranger spacecraft. It was powered by a pair of 1.5 m long solar panels and was equipped with a science payload of six television vidicon cameras transmitting data via the pointable high gain antennae mounted at the base.
Ranger 7 was the first successful mission in the Ranger series. The flight was entirely successful and was followed by Ranger’s 8 and 9. They were built by NASA’s Jet Propulsion Laboratory, Pasadena, California.
Here’s a short 1964 documentary chronicling Ranger 7 titled “Lunar Bridgehead” that truly harkens back to the 1950s and 1960s and sci fi movies of the time. No wonder since that’s when it was produced.
Video Caption. This 1964 documentary titled “Lunar Bridgehead produced by NASA’s Jet Propulsion Laboratory, Pasadena, California, chronicles the moments leading up to and following the Ranger 7 mission’s lunar impact 50 years ago. Credit: NASA/JPL-Caltech
During the 1960’s NASA implemented an ambitions three pronged strategy of robotic missions – including Ranger, Lunar Orbiter and Surveyor – that imaged the Moon and studied it’s physical and chemical properties and supported and enabled the Apollo program and led directly to Neil Armstrong stepping onto the alien lunar landscape.
Three members of the Ranger 7 television experiment team stand near a scale model and lunar globe at NASA’s Jet Propulsion Laboratory (JPL). From left: Ewen Whitaker, Dr. Gerard Kuiper, and Ray Heacock. Kuiper was the director of the Lunar and Planetary Laboratory (LPL) at the University of Arizona. Whitaker was a research associate at LPL. Heacock was the Lunar and Planetary Instruments section chief at JPL. Credit: NASA/JPL-Caltech
Read more about pathfinding space missions in my earlier space history story about Mariner 10 – the first space probe to ever carry out a planetary gravity assist maneuver used to alter its speed and trajectory – in order to reach another celestial body – here.
Liftoff of Ranger 7 on July 28, 1964 from Cape Kennedy at Launch Complex 12. Credit: NASANeil Armstrong and Buzz Aldrin plant the US flag on the Lunar Surface during 1st human moonwalk in history 45 years ago on July 20, 1969 during Apollo 11 mission. Credit: NASA
Comet 67P/Churyumov-Gerasimenko at 621 miles (1,000 km) on August 1. Wow! Look at that richly-textured surface. This photo has higher resolution than previous images because it was taken with Rosetta's narrow angle camera. The black spot is an artifact. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
We’re finally getting to know the icy nucleus behind comet 67P/Churyumov-Gerasimenko. For all the wonder that comets evoke, we on Earth never see directly what whips up the coma and tail. Even professional telescopes can’t burrow through the dust and vapor cloaking the nucleus to distinguish the clear outline of a comet’s heart. The only way to see one is to fly a camera there.
Asteroids we’ve seen up close show cratered surfaces similar to yet different from much of the cratering so far seen on comets. Not to scale. Credit: NASA except for Steins (ESA)
Rosetta took 10 years to reach 67P/C-G, a craggy, boot-shaped body that resembles an asteroid in appearance but with key differences. Asteroids shown in close up photos often display typical bowl-shaped impact craters. From the photos to date, 67P/C-G’s ‘craters’ look shallow and flat in comparison. Were they impacts smoothed by ice flows over time? Did some of the dust and vapor spewed by the comet settle back on the surface to partially bury and soften the landscape?
Comet 81P/Wild 2 photographed during the Stardust mission in 2004. Wild 2 measures 1.03 x 1.24 x 1.71 miles and goes around the sun once every 6.4 years. Its surfaced is riddled with flat-bottomed depressions some of which may also vent gas from vaporizing ice. Click for more 81P/Wild 2 photos. Credit: NASA
While 67P is doubtless its own comet, it does share certain similarities with Comet 81P/Wild including at least a few crater-like depressions seen during NASA’s Stardust mission. In January 2004, the spacecraft gathered photos, measurements and dust samples during its brief flyby of the nucleus. Photos reveal pinnacles, flat-bottomed depressions and bright plumes or jets of vaporizing ice.
Some of the comets we’ve seen close up through the eyes of visiting spacecraft. Credit: NASA
In a 2004 paper by Donald Brownlee and team, the group experimentally reproduced the flat-floored craters by firing projectiles into resin-coated sand baked a bit to make it cohere. Their results suggest the craters formed from impacts in loosely compacted material under the low-gravity conditions typical of small objects like comets. To quote the paper: “Most disrupted material stayed inside the cavity and formed a flat-floored deposit and steep cliffs formed the rim.” Icy materials mixed with dust may have also played a role in their appearance and other crater-like depressions called pit-halos.
Latest image of the comet taken by Rosetta’s navigation camera from a distance of only 311 miles (500 km) on August 2, 2014. The comet’s larger size in the field means fewer artifacts. Credit: ESA/Rosetta/Navcam
Speculation isn’t science, so I’ll stop here. So much more data will be streaming in soon, we’ll have our hands full. On Wednesday, August 6th, Rosetta will enter orbit around the nucleus and begin detailed studies that will continue through December 2015. Studying the new pictures now arriving daily, I’m struck by the dual nature of comets. We see an ancient landscape and yet one that looks strangely contemporary as the sun vaporizes ice, reworking the terrain like a child molding clay.
Comet 67P/Churyumov-Gerasimenko is well-placed in the mid-summer sky in Sagittarius but impossibly faint visually. Dave Herald’s photo taken on August 21, 2014 shows only a tiny fuzz of magnitude +21. Credits: Dave Herald; Stellarium
ESA’s Rosetta Spacecraft nears final approach to Comet 67P/Churyumov-Gerasimenko in late July 2014. This collage of imagery from Rosetta combines Navcam camera images at right taken nearing final approach from July 25 (3000 km distant) to July 31, 2014 (1327 km distant), with OSIRIS wide angle camera image at left of comet’s expanding coma cloud on July 25. Images to scale and contrast enhanced to show further detail. Credit: ESA/Rosetta/NAVCAM/OSIRIS/MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA Collage/Processing: Marco Di Lorenzo/Ken Kremer
ESA’s Rosetta Spacecraft nears final approach to Comet 67P/Churyumov-Gerasimenko in late July 2014. This collage of imagery from Rosetta combines Navcam camera images at right taken nearing final approach from July 25 to July 31, 2014, with OSIRIS wide angle camera image at left of comet’s coma on July 25 from a distance of around 3000 km. On July 31 Rosetta had approached to within 1327 km. Images to scale and contrast enhanced to show further detail. Credit: ESA/Rosetta/NAVCAM/OSIRIS/MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA Collage/Processing: Marco Di Lorenzo/Ken Kremer – kenkremer.com Story updated[/caption]
The European Space Agency’s (ESA) Rosetta spacecraft is at last rapidly closing in on its target destination, Comet 67P/Churyumov-Gerasimenko, after a decade long chase of 6.4 billion kilometers through interplanetary space. See imagery above and below.
As of today, Friday, August 1, ESA reports that Rosetta has approached the ‘rubber ducky looking’ comet to within a distance of less than 1153 kilometers. That distance narrows with each passing moment as the speeding robotic probe moves closer and closer to the comet while looping around the sun at about 55,000 kilometers per hour (kph).
Rosetta is now just 5 days away from becoming Earth’s first probe ever to rendezvous and enter orbit around a comet.
See above our image collage of Rosetta nearing final approach with the spacecrafts most recent daily Navcam camera images, all taken within the past week starting on July 25 and including up to the most recently release image snapped on July 31. The navcam images are all to scale to give the sense of the spacecraft approaching the comet and revealing ever greater detail as it grows in apparent size in the cameras field of view. The navcam images were also taken at about the same time of day each day.
The highest resolution navcam image yet of the two lobed comet – merged at a bright band – was taken on July 31 from a distance of 1327 kilometers and published within the past few hours by ESA today, Aug 1. It shows the best view yet of the surface features of the mysterious bright necked wanderer composed of primordial ice, rock, dust and more.
The Navcam collage is combined with an OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) wide angle camera view of the comet and its asymmetric coma of ice and dust snapped on July 25 from a distance of around 3000 km, and with an exposure time of 300 seconds. The OSIRIS image covers an area of about 150 x 150 km (90 mi x 90 mi). The images have been contrast enhanced to bring out more detail.
Scientists speculate that the comets bright neck region could be caused by differences in material or grain size or topological effects.
Rosetta’s history making orbital feat is slated for Aug. 6 following the final short duration orbit insertion burns on Aug. 3 and Aug. 6 to place Rosetta into orbit at an altitude of about 100 kilometers (62 miles) where it will study and map the 4 kilometer wide comet for some 17 months.
The comet rotates around once every 12.4 hours.
Crop from the 31 July processed image of comet 67P/Churyumov-Gerasimenko, to focus on the comet nucleus. Credits: ESA/Rosetta/NAVCAM
“If any glitches in space or on ground had delayed the most recent burns, orbital mechanics dictate that we’d only have had a matter of a few days to fix the problem, re-plan the burn and carry it out, otherwise we run the risk of missing the comet,” says Trevor Morley, a flight dynamics specialist at ESOC.
In November 2014 the Rosetta mothership will deploy the Philae science lander for the first ever attempt to land on a comet’s nucleus using harpoons to anchor itself to the surface while the comet is rotating.
As Rosetta edges closer on its final lap, engineers at mission control at the European Space Operations Centre (ESOC), in Darmstadt, Germany have commanded the probes navigation camera (navcam) to capture daily images while the other science instruments also collect measurements analyzing the comets physical characteristics and chemical composition in detail.
ESA’s Rosetta Spacecraft nears final approach to Comet 67P/Churyumov-Gerasimenko in late July 2014. This image collage from Rosetta combines Navcam camera images taken nearing final approach from July 25 (3000 km distant) to July 31, 2014 (1327 km distant). Top row shows images as seen by spacecraft. Bottom row shows images rotated to same orientation. Images to scale and contrast enhanced to show further detail. Credit: ESA/Rosetta/NAVCAM. Collage/Processing: Marco Di Lorenzo/Ken Kremer
The probe has already discovered that the comet’s surface temperature is surprisingly warm at –70ºC, which is some 20–30ºC warmer than predicted. This indicates the surface is too hot to be covered in ice and must instead have a dark, dusty crust, says ESA.
Comet 67P/Churyumov-Gerasimenko is a short period comet some 555 million kilometres from the Sun at this time, about three times further away than Earth and located between the orbits of Jupiter and Mars.
You can watch the Aug. 6 orbital arrival live via a livestream transmission from ESA’s spacecraft operations centre in Darmstadt, Germany.
While you were reading this the gap between the comet and Rosetta closed to less than 1000 kilometers!
The coma of Rosetta’s target comet as seen with the OSIRIS wide-angle camera. The image spans 150 km and was taken on 25 July 2014 with an exposure time of 330 seconds. The greyscale relates to the particle density in the coma, with highest density close to the nucleus, becoming more diffuse further away. The hazy circular structure on the right is an artefact. The nucleus is also overexposured. The specks and the streaks in the background are attributed to background stars and cosmic rays. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Stay tuned here for Ken’s continuing Curiosity, Opportunity, Orion, SpaceX, Boeing, Orbital Sciences, commercial space, MAVEN, MOM, Mars and more Earth and Planetary science and human spaceflight news.
ESA’s Rosetta Spacecraft nears final approach to Comet 67P/Churyumov-Gerasimenko in late July 2014. This collage of imagery from Rosetta combines Navcam camera images at right taken nearing final approach from July 25 (3000 km distant) to July 31, 2014 (1327 km distant), with negative OSIRIS wide angle camera image at left of comet’s expanding coma cloud on July 25. Images to scale and contrast enhanced to show further detail. Credit: ESA/Rosetta/NAVCAM/OSIRIS/MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA Collage/Processing: Marco Di Lorenzo/Ken Kremer Birthday cakes at @ESA_Rosetta Flight Dynamics are taking strange binary shapes these days… #ESOC. Credit: ESA
