Mickey Mouse on Mercury?

This collection of craters, shaped not unlike the iconic head of a certain cartoon mouse, was imaged by NASA’s MESSENGER spacecraft on June 3, 2012.

All together now: C-R-A, T-E-R… M-O-U-S-Eeeeee…

Acquired as part of MESSENGER’s extended mission to map Mercury’s surface in higher detail, the image above isn’t map-projected; that is, it’s not aligned with north as up. In reality the large crater that makes up Mickey’s “head” is north of the two “ears”.

Still, this is one big mouse head — the large crater in the center has a diameter of approximately 105 km (65 miles)!

Read more about this and see many other images of the first rock from the Sun on the MESSENGER mission site here.

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Is It Time to Return to the Moon?

Should we pay another visit to the Moon? (From "Le Voyage Dans La Lune" by Georges Méliès, 1902)

Humans haven’t set foot on the Moon — or any other world outside of our own, for that matter — since Cernan and Schmitt departed the lunar surface on December 14, 1972. That will make 40 years on that date this coming December. And despite dreams of moon bases and lunar colonies, there hasn’t even been a controlled landing there since the Soviet Luna 24 sample return mission in 1976 (not including impacted probes.) So in light of the challenges and costs of such an endeavor, is there any real value in a return to the Moon?

Some scientists are saying yes.

Researchers from the UK, Germany and The Netherlands have submitted a paper to the journal Planetary and Space Science outlining the scientific importance of future lunar surface missions. Led by Ian A. Crawford from London’s Birkbeck College, the paper especially focuses on the value of the Moon in the study of our own planet and its formation, the development of the Earth-Moon system as well as other rocky worlds  and even its potential contribution in life science and medicinal research.

Even though some research on the lunar surface may be able to be performed by robotic missions, Crawford et al. ultimately believe that “addressing them satisfactorily will require an end to the 40-year hiatus of lunar surface exploration.”

The team’s paper outlines many different areas of research that would benefit from future exploration, either manned or robotic. Surface composition, lunar volcanism, cratering history — and thus insight into a proposed period of “heavy bombardment” that seems to have affected the inner Solar System over 3.8 billion years ago — as well as the presence of water ice could be better investigated with manned missions, Crawford et al. suggest.

(Read: A New Look At Apollo Samples Supports Ancient Impact Theory)

In addition, the “crashed remains of unsterilized spacecraft” on the Moon warrant study, proposes Crawford’s team. No, we’re not talking about alien spaceships — unless the aliens are us! The suggestion is that the various machinery we’ve sent to the lunar surface since the advent of the Space Age may harbor Earthly microbes that could be returned for study after decades in a lunar environment. Such research could shed new light on how life can — or can’t — survive in a space environment, as well as how long such “contaminants” might linger on another world.

Crawford’s team also argues that only manned missions could offer all-important research on the long-term effects of low-gravity environments on human physiology, as well as how to best sustain exploration crews in space. If we are to ever become a society with the ability to explore and exist beyond our own planet, such knowledge is critical.

And outside of lunar exploration itself, the Moon offers a place from which to perform deeper study of the Universe. The lunar farside, shielded as it is from radio transmissions and other interference from Earth, would be a great place for radio astronomy — especially in the low-frequency range of 10-30 MHz, which is absorbed by Earth’s ionosphere and is thus relatively unavailable to ground-based telescopes. A radio observatory on the lunar farside would have a stable platform from which to observe some of the earliest times of the Universe, between the Big Bang and the formation of the first stars.

Of course, before anything can be built on the Moon or retrieved from its surface, serious plans must be made for such missions. Fortunately, says Crawford’s team, the 2007 Global Exploration Strategy — a framework for exploration created by 13 space agencies from around the world — puts the Moon as the “nearest and first goal” for future missions, as well as Mars and asteroids. Yet with subsequent budget cuts for NASA (a key player for many exploration missions) when and how that goal will be reached still remains to be seen.

See the team’s full paper on arXiv.org here, and check out a critical review on MIT’s Technology Review.

“…this long hiatus in lunar surface exploration has been to the detriment of lunar and planetary science, and indeed of other sciences also, and that the time has come to resume the robotic and human exploration of the surface of the Moon.”

— Ian A. Crawford,  Department of Earth and Planetary Sciences, Birkbeck College, UK

 Top image from “Le Voyage Dans La Lune” by Georges Méliès, 1902. Second image: First photo of the far side of the Moon, acquired by the Soviet Luna-3 spacecraft on Oct. 7, 1959.

On the Edge of Titan

Titan's haze-covered limb seen by Cassini on June 6

[/caption]

Here’s a quick look at one of my favorite cosmic photo subjects – the varying layers of atmosphere that enshroud Saturn’s enormous moon Titan. The image above is a color-composite made from three raw images acquired by Cassini during its latest flyby.

On June 7 Cassini approached Titan within 596 miles (959 km) and imaged portions of the moon’s northwest quadrant with its radar instrument, as well as conducted further investigations of areas near the equator where surface changes were detected in 2010.

The image here was assembled from three raw images captured in red, green and blue visible light channels. It reveals some structure in the upper hydrocarbon haze layers that extend upwards above the moon’s opaque orange clouds — reaching 400-500 km in altitude, Titan’s atmosphere is ten times thicker than Earth’s!

The June 6 flyby was the second in a series of passes that will take Cassini into a more inclined orbit, where it will reside for the next three years as it investigates Saturn’s polar regions and obtains better views of its ring system.

Read more about the flyby here.

Image: NASA/JPL/Space Science Institute. Composite by J. Major.

Was Pluto Ever REALLY a Planet?

Pluto, Charon, Nix and Hydra (NASA)

Ever since the infamous 2006 reclassification of Pluto off the list of “official” planets (which had a rather incendiary effect on many of the distant world’s Earthly fans) the term “planet” has been seen by some as a variable one, difficult to define and apparently able to be given and taken away. But was Pluto ever really deserving of the title to begin with?

This fun info-animation by C.G.P. Grey suggests that it wasn’t, and offers a compelling explanation why.

[/caption]

Grey writes on his blog:

“To my constant surprise the issue of Pluto’s planetary status — which I think should be a dry technical issue — really gets people riled. But it’s also been my experience that the people who most want Pluto to be a planet know the least about it and the history of its discovery. So, I hope that this video can help correct that a little bit.”

We still love you, Pluto, no matter what you are!

See more of Grey’s excellent animations on YouTube here.

How To Measure the Universe

The Royal Observatory Greenwich is giving free presentations of "Measuring the Universe: from the Transit of Venus to the Edge of the Cosmos" from now until September 1.


Measuring distance doesn’t sound like a very challenging thing to do — just pick your standard unit of choice and corresponding tool calibrated to it, and see how the numbers add up. Use a meter stick, a tape measure, or perhaps take a drive, and you can get a fairly accurate answer. But in astronomy, where the distances are vast and there’s no way to take measurements in person, how do scientists know how far this is from that and what’s going where?

Luckily there are ways to figure such things out, and the methods that astronomers use are surprisingly familiar to things we experience every day.

[/caption]The video above is shared by the Royal Observatory Greenwich and shows how geometry, physics and things called “standard candles” (brilliant!) allow scientists to measure distances on cosmic scales.

Just in time for the upcoming transit of Venus, an event which also allows for some important measurements to be made of distances in our solar system, the video is part of a series of free presentations the Observatory is currently giving regarding our place in the Universe and how astronomers over the centuries have measured how oh-so-far it really is from here to there.

Video credits:
Design and direction: Richard Hogg
Animation: Robert Milne, Ross Philips, Kwok Fung Lam
Music and sound effects: George Demure
Narration and Astro-smarts: Dr. Olivia Johnson
Producer: Henry Holland

ESA: Unveiling Venus

The featureless face of Venus, as seen by MESSENGER (NASA/Gordan Ugarkovic)

[/caption]

With Venus about to get its day in the Sun — very much literally — the European Space Agency has assembled an excellent video about our planetary neighbor.

Watch the video below: 

Once thought to be similar to Earth, possibly even having liquid water and plant life on its surface, Venus has since been discovered to be anything but hospitable to life. Beneath its cream-colored clouds lies a hellish hothouse of searing temperatures and crushing pressure, making attempts at exploration difficult at best. But ESA’s Venus Express, currently in orbit around the planet, has helped scientists learn more about Venus than ever before, opening our eyes to what really lies beneath — and within — its opaque atmosphere.

Venus is still a planet shrouded in mystery (and sulfuric acid clouds!) but we are gradually pulling away the veil.

Video: ESA

Cassini Captures a Rarely-Seen Moon

Closest view of Saturn's moon Methone ever captured by Cassini

[/caption]

While many of us here on Earth were waiting for the Moon to take a bite out of the Sun this past Sunday, Cassini was doing some moon watching of its own, 828.5 million miles away!

The image above is a color-composite raw image of Methone (pronounced meh-tho-nee), a tiny, egg-shaped moon only 2 miles (3 km) across. Discovered by Cassini in 2004, Methone’s orbit lies between Mimas and Enceladus, at a distance of 120,546 miles (194,000 km) from Saturn — that’s about half the distance between Earth and the Moon.

At an altitude of 1,200 miles (1900 km) this was Cassini’s closest pass ever of Methone, a rare visit that occurred after the spacecraft departed the much larger Tethys.

Along with sister moons Pallene and Anthe, Methone is part of a group called the Alkyonides, named after daughters of the god Alkyoneus in Greek mythology. The three moons may be leftovers from a larger swarm of bodies that entered into orbit around Saturn — or they may be pieces that broke off from either Mimas or Enceladus.

Earlier on Sunday, May 20, Cassini paid a relatively close visit to Tethys (pronounced tee-this), a 662-mile (1065-km) -wide moon made almost entirely of ice. One of the most extensively cratered worlds in the Solar System, Tethys’ surface is dominated by craters of all sizes — from the tiniest to the giant 250-mile (400-km) -wide Odysseus crater — as well as gouged by the enormous Ithaca Chasma, a series of deep valleys running nearly form pole to pole.

Saturn's icy moon Tethys with Ithaca Chasma visible, seen by Cassini on May 20, 2012.
Tethys' rugged and heavily-cratered surface near the terminator
Cassini looks down into the 62 mile (100 km) wide Ithaca Chasma

Cassini passed within 34,000 miles (54,000 km) of Tethys on May 20, before heading to Methone and then moving on to its new path toward Titan, a trajectory that will eventually take it up out of Saturn’s equatorial plane into a more inclined orbit in order to better image details of the rings and  Saturn’s poles.

Read more about this flyby on the Cassini mission site here. and see more raw images straight from the spacecraft on the CICLOPS imaging lab site here.

Image credit: NASA / JPL / Space Science Institute. (Color-composite image edited by J. Major.)

The Big Dipper Like You’ve Never Seen It Before!

Junocam image of the stars that make up the "Big Dipper" asterism

[/caption]

All right, it may look just like any other picture you’ve ever seen of the Big Dipper. Maybe even a little less impressive, in fact. But, unlike any other picture, this one was taken from 290 million km away by NASA’s Juno spacecraft en route to Jupiter, part of a test of its Junocam instrument!  Now that’s something new concerning a very old lineup of stars!

“I can recall as a kid making an imaginary line from the two stars that make up the right side of the Big Dipper’s bowl and extending it upward to find the North Star,” said Scott Bolton, principal investigator of NASA’s Juno mission. “Now, the Big Dipper is helping me make sure the camera aboard Juno is ready to do its job.”

Diagram of the Juno spacecraft (NASA/JPL)

The image is a section of a larger series of scans acquired by Junocam between 20:23 and 20:56 UTC (3:13 to 3:16 PM EST) on March 14, 2012. Still nowhere near Jupiter, the purpose of the imaging exercise was to make sure that Junocam doesn’t create any electromagnetic interference that could disrupt Juno’s other science instruments.

In addition, it allowed the Junocam team at Malin Space Science Systems in San Diego, CA to test the instrument’s Time-Delay Integration (TDI) mode, which allows image stabilization while the spacecraft is in motion.

Because Juno is rotating at about 1 RPM, TDI is crucial to obtaining focused images. The images that make up the full-size series of scans were taken with an exposure time of 0.5 seconds, and yet the stars (brightened above by the imaging team) are still reasonably sharp… which is exactly what the Junocam team was hoping for.

“An amateur astrophotographer wouldn’t be very impressed by these images, but they show that Junocam is correctly aligned and working just as we expected”, said Mike Caplinger, Junocam systems engineer.

As well as the Big Dipper, Junocam also captured other stars and asterisms, such as Vega, Canopus, Regulus and the “False Cross”. (Portions of the imaging swaths were also washed out by sunlight but this was anticipated by the team.)

These images will be used to further calibrate Junocam for operation in the low-light environment around Jupiter, once Juno arrives in July 2016.

Read more about the Junocam test on the MSSS news page here.

As of May 10, Juno was approximately 251 million miles (404 million kilometers) from Earth. Juno has now traveled 380 million miles (612 million kilometers) since its launch on August 5, 2011 and is currently traveling at a velocity of 38,300 miles (61,600 kilometers) per hour relative to the Sun.

Watch a video of the Juno launch here, taken by yours truly from the press site at Kennedy Space Center!

Space Exploration By Robot Swarm

"Hopper" rover/spacecraft concept by Stanford University's Marco Pavone

[/caption]

With all there’s yet to learn about our solar system from the many smaller worlds that reside within it — asteroids, protoplanets and small moons — one researcher from Stanford University is suggesting we unleash a swarm of rover/spacecraft hybrids that can explore en masse.

Marco Pavone, an assistant professor of aeronautics and astronautics at Stanford University and research affiliate at JPL, has been developing a concept under NASA’s Innovative Advanced Concepts (NIAC) Program that would see small spherical robots deployed to small worlds, such as Mars’ moons Phobos and Deimos, where they would take advantage of low gravity to explore — literally —  in leaps and bounds.

Due to the proposed low costs of such a mission, multiple spacecraft could be scattered across a world, increasing the area that could be covered as well as allowing for varied surfaces to be explored. Also, were one spacecraft to fail the entire mission wouldn’t be compromised.

The concept is similar to what NASA has done in the past with the Mars rovers, except multiplied in the number of spacecraft (and reduced in cost.)

The robots would be deployed from a “mother” spacecraft and spring into action upon landing, tumbling, hopping and vaulting their way across low-mass worlds.

In addition to providing our first views from the surfaces of such worlds, Pavone’s hybrid rovers could also help prepare for future, more in-depth exploration.

“The systematic exploration of small bodies would help unravel the origin of the solar system and its early evolution, as well as assess their astrobiological relevance,” Pavone explains. “In addition, we can evaluate the resource potential of small bodies in view of future human missions beyond Earth.”

Read more from NASA’s Office of the Chief Technologist here.

Photo courtesy of Marco Pavone

Warhol Crater Gets Its 15 Minutes of Fame

Warhol crater, one of 23 recently named craters on Mercury

[/caption]

As pop art icon Andy Warhol said, “In the future everyone will be famous for fifteen minutes,”  and so here’s an image of the crater on Mercury that now bears his name, set up in the style of one of his multicolored silkscreens.

Warhol is one of 23 craters on Mercury to be recently approved for names by the International Astronomical Union (IAU), joining other notable artists, authors and musicians like Gustav Holst, Rene Magritte and Dr. Seuss who now have craters named in their honor on the first rock from the Sun.

95 km (59 miles) in diameter, Warhol crater features a large, elongated central peak, stepped walls and many of the curious erosions known as hollows.

The original image, seen at top left, was acquired by NASA’s MESSENGER spacecraft on October 21, 2011, using its Wide-Angle Camera Mercury Dual Imaging System (MDIS) instrument.

With the new list of 23 named craters, there are now 76 officially (and artistically) titled craters on Mercury since MESSENGER’s first pass of the planet in January 2008.

See the original release by the MESSENGER mission team here.

“I’m bored with that line. I never use it anymore. My new line is “In 15 minutes everybody will be famous.”
– Andy Warhol (1928 – 1987)

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington