Mercury Archives

June 18, 2014December 23, 2015 by Jason Major

Mercury’s Hot Flow Revealed by MESSENGER

A hot flow anomaly, or HFA, has been identified around Mercury (Credit: NASA/Duberstein)

Our Sun is constantly sending a hot stream of charged atomic particles out into space in all directions. Pouring out from holes in the Sun’s corona, this solar wind flows through the Solar System at speeds of over 400 km/s (that’s 893,000 mph). When it encounters magnetic fields, like those generated by planets, the flow of particles is deflected into a bow shock — but not necessarily in a uniform fashion. Turbulence can occur just like in air flows on Earth, and “space weather” results.

One of the more curious effects is a regional reversal of the flow of solar wind particles. Called a “hot flow anomaly,” or HFA, these energetic phenomena occur almost daily in Earth’s magnetic field, as well as on Jupiter and Saturn, and even on Mars and Venus where the magnetic fields are weak (but there are still planets blocking the stream of charged particles.)

Not to be left out in the cold, Mercury is now known to display HFAs, which have been detected for the first time by the MESSENGER spacecraft.

A NASA news release describes how the HFAs were confirmed:

The first measurement was of magnetic fields that can be used to detect giant electric current sheets that lead to HFAs. The second was of the heating of the charged particles. The scientists then analyzed this information to quantify what kind of turbulence exists in the region, which provided the final smoking gun of an HFA.

“Planets have a bow shock the same way a supersonic jet does,” explains Vadim Uritsky at NASA’s Goddard Space Flight Center. “These hot flow anomalies are made of very hot solar wind deflected off the bow shock.”

The solar wind is not 100% uniform; it has discontinuities within its own complex magnetic fields. When these shifting fields pile up against a planet’s bow shock they can create turbulence patterns that trap hot plasma, which in turn produces its own magnetic fields. The shockwaves, heat, and energy produced are powerful enough to actually reverse the flow of the solar wind within the HFA bulge.

And the word “hot” is putting it lightly — plasma temperatures in an HFA can reach 10 million degrees.

Mercury may be only a little larger than our Moon but it does possess an internally-generated dipolar magnetic field, unlike the Moon, Venus, and Mars which have only localized or shallow fields. The confirmed presence of HFAs on Mercury indicates that they may be a feature in all planetary bow shocks, regardless of how their magnetic fields — if any — are produced.

The team’s results were published in the February 2014 issue of the Journal of Geophysical Research: Space Physics.

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In related news, on June 17 MESSENGER successfully completed the first orbit adjustment maneuver to prepare it for its new — and final — low-altitude campaign, during which it will obtain its highest-resolution images ever of the planet’s surface and perform detailed investigations of its composition and magnetic field. Read more on the MESSENGER site here.

Source: NASA

June 10, 2014December 23, 2015 by Jason Major

Curiosity Captures Mercury from Mars

Image of the Sun as seen from Mars by Curiosity. Mercury is the circled dark spot.

NASA’s Curiosity rover may be busy exploring the rugged and rocky interior of Gale Crater, but it does get a chance to skygaze on occasion. And while looking at the Sun on June 3, 2014 (mission Sol 649) the rover’s Mastcam spotted another member of our Solar System: tiny Mercury, flitting across the Sun’s face.

Silhouetted against the bright disk of the Sun, Mercury barely appears as a hazy blur in the filtered Mastcam images. But it was moving relatively quickly during the transit, passing the darker smudges of two Earth-sized sunspots over the course of several hours.

It’s the first time Mercury has ever been imaged from Mars, and also the first time we’ve observed a planet transiting our Sun from another world besides our own.

Watch an animation of the transit below:

Animated blink comparison showing Mercury's movement across the Sun — Animated 1-hour interval blink comparison showing Mercury’s movement across the Sun

Because the sunspots move along with the rotation of the Sun (and the Sun rotates once avery 25 days around its equator) Mercury makes a fast pass as it travels along on one of its 88-day-long years.

Watch an HD version of the event here.

In reality this was no chance spotting, but rather a carefully calculated observation using the Mastcam’s right 100mm telephoto lens and neutral density filter, which is used to routinely image the Sun in order to measure the dustiness of the Martian atmosphere.

“This is a nod to the relevance of planetary transits to the history of astronomy on Earth. Observations of Venus transits were used to measure the size of the solar system, and Mercury transits were used to measure the size of the sun.”

– Mark Lemmon, Texas A&M University, member of the Mastcan science team

The next chance for Curiosity to spot Mercury will come in April 2015 and, if the rover is still operating by then — perhaps with some upgrades by future human visitors? — it may capture Earth similarly passing across the Sun in November of 2084.

Source: NASA/JPL

Image/animation credit: NASA/JPL-Caltech/MSSS/Texas A&M

May 15, 2014December 23, 2015 by Jason Major

Mercury’s Ready For Its Close-Up, Mr. MESSENGER

One of the highest-resolution images of Mercury's surface ever acquired.

Are you ready for a good close look at Mercury? At an incredible 5 meters per pixel, this is one of the highest-resolution images of Mercury’s surface ever captured. It was acquired on March 15 with the MESSENGER spacecraft’s MDIS (Mercury Dual Imaging System) instrument and shows an 8.3-km (5.2-mile) -wide section of Mercury’s north polar region, speckled with small craters and softly rolling hills.

Because MESSENGER was moving so quickly relative to the targeted area it was imaging, a short exposure time was necessary to avoid blurring. As a result the image appears a bit grainy. See the original map projection here.

Wondering what the next-best image was of Mercury? Find out below:

The previous record for most extreme close-up of Mercury was held by this image:

7 meter/pixel targeted observation of Mercury by the MESSENGER spacecraft

It was acquired as a targeted observation by MESSENGER’s Narrow-Angle Camera on April 30, 2012, and has a resolution of 7 meters/pixel. It shows an impact melt-covered area about 11 km (7 miles) across near Gaugin crater.

(Although Mercury’s surface may at first appear strikingly similar to the Moon’s, it’s been known since the Mariner 10 mission that the two worlds are very different at fundamental geologic and compositional levels. Read more on that here.)

Images like these are extremely special; during the first two years of MESSENGER’s mission in orbit around Mercury, over 150,000 images were acquired but only five images had resolutions better than 10 meters per pixel.

Artist's impression of MESSENGER orbiting Mercury — Artist’s impression of MESSENGER orbiting Mercury

On April 20, 2014, MESSENGER completed its 3,000th orbit of Mercury (3,075 to date) and is steadily moving into an even lower-altitude orbit. MESSENGER now comes within less than 200 km (124 miles) of the planet’s surface when it passes over its north pole every eight hours… that’s less than half the altitude of the Space Station!

Orbiting at such a low altitude and so often will allow MESSENGER to examine Mercury’s surface in unprecedented detail. Now that 100% of the planet has been successfully mapped by MESSENGER it can spend its second — and last — extended mission investigating specific scientific targets.

Watch: A Tribute to MESSENGER

“The final year of MESSENGER’s orbital operations will be an entirely new mission,” said Sean Solomon, Principal Investigator for MESSENGER. “With each orbit, our images, our surface compositional measurements, and our observations of the planet’s magnetic and gravity fields will be higher in resolution than ever before. We will be able to characterize Mercury’s near-surface particle environment for the first time. Mercury has stubbornly held on to many of its secrets, but many will at last be revealed.”

Read more in a recent news release from the MESSENGER team here.

Want to explore a high-res map of Mercury and see where MESSENGER is right now? Click here.

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

May 9, 2014December 23, 2015 by Bob King

Observing Alert: See Mercury’s Best Evening Show of the Year

Mercury starts its best period of visibility in the evening sky for skywatchers at mid-northern latitudes this weekend. This map shows the sky facing northwest about 40 minutes after sundown. Bright Jupiter also provides a convenient sightline for locating Mercury. Stellarium

Don’t let furtive Mercury slip through your fingers this spring. The next two and a half weeks will be the best time this year for observers north of the tropics to spot the sun-hugging planet. If you’ve never seen Mercury, you might be surprised how bright it can be. This is especially true early in its apparition when the planet looks like a miniature ‘full moon’.

Mercury, like Venus, displays phases as it revolves around the sun as seen from Earth's perspective outside Mercury's orbit. Credit: Bob King — Mercury, like Venus, displays phases as it revolves around the sun as seen from Earth’s perspective outside Mercury’s orbit. Both Mercury and Venus appear largest when nearly lined up between Earth and sun at inferior conjunction. Planets not to scale and phases shown are approximate. Credit: Bob King

Both Venus and Mercury pass through phases identical to those of the moon. When between us and the sun, Mercury’s a thin crescent, when off to one side, a ‘half-moon’ and when on the far side of the sun, a full moon. This apparition of the planet is excellent because Mercury’s path it steeply tilted to the horizon in mid-spring.

We start the weekend with Mercury nearly full and brighter than the star Arcturus. Twilight tempers its radiance, but :

* Find a location with a wide open view to the northwest as far down to the horizon as possible.

* Click HERE to get your sunset time and begin looking for the planet about 30-40 minutes after sunset in the direction of the sunset afterglow.

* Reach your arm out to the northwestern horizon and look a little more than one vertically-held fist (10-12 degrees) above it for a singular, star-like object. Found it? Congratulations – that’s Mercury!

* No luck? Start with binoculars instead and sweep the bright sunset glow until you find Mercury. Once you know exactly where to look, lower the binoculars from your eyes and you should see the planet without optical aid. And before I forget – be sure to focus the binoculars on a distant object like a cloud or the moon before beginning your sweeps. I guarantee you won’t find Mercury if it’s out of focus.

Through a telescope, Mercury looks like a gibbous moon right now but its phase will lessen as it moves farther to the ‘left’ or east of the sun. Greatest eastern elongation happens on May 24. On and around that date the planet will be farthest from the sun, standing 12-14 degrees high 40 minutes after sundown from most mid-northern locales.

jjjjjjj — Mercury is even better placed on May 19 but fades and begins to drop back down toward the horizon late in the month. Stellarium

The planet fades in late May and become difficult to see by early June. Inferior conjunction, when Mercury passes between the Earth and sun, occurs on June 19. Unlike Venus, which remains brilliant right up through its crescent phase, Mercury loses so much reflective surface area as a crescent that it fades to magnitude +3. Its greater distance from Earth, lack of reflective clouds and smaller size can’t compete with closer, brighter and bigger Venus.

Mercury's path across the solar disk as seen from the Solar and Heliospheric Observatory (SOHO) on November 8, 2006. The transit was visible in eastern Europe and the eastern hemisphere. Credit: NASA. — When a planet crosses the disk of the sun it’s called a transit. Mercury’s path across the solar disk is seen from the Solar and Heliospheric Observatory (SOHO) on November 8, 2006. Credit: NASA.

Mercury’s 7-degree inclined orbit means it typically glides well above or below the sun’s disk at inferior conjunction. But anywhere from 3 up to 13 years in either November or May the planet passes directly between the Earth and sun at inferior conjunction and we witness a transit. This last happened for U.S. observers on Nov. 8, 2006; the next transit occurs exactly two years from today on May 9, 2016. That event will be widely visible across the Americas, Western Europe and Africa. After having so much fun watching the June 2012 transit of Venus I can’t wait.

April 9, 2014December 23, 2015 by Elizabeth Howell

Mercury Had Quite The Explosive Past, Spacecraft Analysis Shows

Mercury — a planet once thought to have no volcanism at all — likely had a very active past, a new analysis of images from NASA’s MESSENGER spacecraft shows. After looking at 51 vents across Mercury, the team concluded that they show different amounts of erosion — hinting that the explosions happened at different times in the planet’s history.

“If [the explosions] happened over a brief period and then stopped, you’d expect all the vents to be degraded by approximately the same amount,” stated Goudge, a graduate geology student at Brown University who led the research.

“We don’t see that; we see different degradation states. So the eruptions appear to have been taking place over an appreciable period of Mercury’s history.”

Information came from orbital data collected from MESSENGER (MErcury Surface, Space ENvironment, GEochemistry and Ranging) since 2011, which provided more consistent data than the previous flybys, the researchers added. To better figure out the age of these vents, they examined those that are located in impact craters; any vents there before the impact occurred would have been wiped out.

Two pyroclastic vents in Mercury's Kipler crater in optical (top) and false-color views from NASA's MESSENGER spacecraft. Pyroclastic material is in brown-red in the bottom image. The vents were likely too fragile to survive the impact of the crater, scientists said, showing that they likely arose after the impact occurred. Credit: Brown University/NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington — Two pyroclastic vents in Mercury’s Kipler crater in optical (top) and false-color views from NASA’s MESSENGER spacecraft. Pyroclastic material is in brown-red in the bottom image. The vents were likely too fragile to survive the impact of the crater, scientists said, showing that they likely arose after the impact occurred. Credit: Brown University/NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

The vents show up along with deposits of pyroclastic ash, which are leftovers of volcanic explosions. This shows that like Earth, the interior of Mercury has volatiles or compounds that have low boiling points. (Earth examples of these are water and carbon dioxide.)

By looking at the pattern of erosion in the craters, Goudge found that there are pyroclastic deposits in craters that are between 1 and 3.5 billion years old. By comparison, Mercury and the rest of the solar system formed about 4.5 billion years ago, and the finding shows the pyroclastic activity happened well after then.

“These ages tell us that Mercury didn’t degas all of its volatiles very early,” Goudge added. “It kept some of its volatiles around to more recent geological times.”

You can read more about the study in the Journal of Geophysical Research.

Source: Brown University

March 26, 2014March 8, 2017 by Fraser Cain

What Are These Hollows on Mercury?

Emily Lakdawalla from the planetary society describes one of the mysteries that’s currently fascinating her. There are strange structures on Mercury which have been called “hollows”. What might they be?
Continue reading “What Are These Hollows on Mercury?”

March 16, 2014December 23, 2015 by Jason Major

Mercury Shrinking: the First Rock from the Sun Contracted More than Once Thought

MESSENGER image of Mercury from its third flyby (NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)

Whatever Mercury’s did to trim down its waistline has worked better than anyone thought — the innermost planet in our Solar System has reduced its radius* by about 7 kilometers (4.4 miles), over double the amount once estimated by scientists.

Of course you wouldn’t want to rush to begin the Mercury diet — its planetary contraction has taken place over the course of 3.8 billion years, since the end of the Late Heavy Bombardment. Still — lookin’ good, Mercury!

These findings come thanks to the MESSENGER spacecraft, in orbit around Mercury since 2011. Now that MESSENGER has successfully mapped literally all of Mercury’s surface, detailed measurements of more than 5,900 landforms created by cooling and contraction of the planet’s crust have allowed researchers to more precisely determine its geologic history and answer some decades-old questions raised by Mariner 10 images.

“This discrepancy between theory and observation, a major puzzle for four decades, has finally been resolved,” said MESSENGER Principal Investigator Sean Solomon. “It is wonderfully affirming to see that our theoretical understanding is at last matched by geological evidence.”

This image shows a long collection of ridges and scarps on the planet Mercury called a fold-and-thrust belt. The belt stretches over 336 miles (540 km). The colors correspond to elevation—yellow-green is high and blue is low. Image courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington. — This image shows a fold-and-thrust belt stretching over 540 km on Mercury. The colors correspond to elevation— yellow/green is high and blue is low. (Courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.)

Using high-definition images acquired with MESSENGER’s MDIS (Mercury Dual Imaging System) instrument, planetary geologist at the Carnegie Institution of Washington and study lead author Paul Byrne and his colleagues identified 5,934 lobate scarps and wrinkle ridges on Mercury that are the result of contraction. From measurements of these features, the team determined that the planet’s radial contraction was much more than that estimated by models based on incomplete imaging from NASA’s Mariner 10 mission — the very first spacecraft to visit (but not orbit) Mercury.

Watch: Fly Across Mercury with MESSENGER!

“These new results resolved a decades-old paradox between thermal history models and estimates of Mercury’s contraction,” said Byrne. “Now the history of heat production and loss and global contraction are consistent.

“Interestingly, our findings are also reminiscent of now-obsolete models for how large-scale geological deformation occurred on Earth when the scientific community thought that the Earth only had one tectonic plate,” Byrne said. “Those models were developed to explain mountain building and tectonic activity in the nineteenth century, before plate tectonics theory.”

Unlike Earth, Mercury has only one global tectonic plate.

The findings were published in the Sunday, March 16 edition of the journal Nature Geoscience.

Source: MESSENGER press release. Read more about tectonic features on Mercury here.

*Mercury’s current radius is 2,440 kilometers (1,516 miles).

February 17, 2014December 23, 2015 by Elizabeth Howell

Savage Spacesuit: ‘Mythbusters’ Host’s Mercury Costume Looks Real Enough For Space

Mythbusters' Adam Savage shows off a Mercury replica spacesuit in February 2014. Credit: Tested/YouTube (screenshot)

Who wants Adam Savage’s job right now? The cohost of Mythbusters spent the last year working with a San Francisco Bay-area costume designer to come up with this remarkable Mercury spacesuit. While it’s not a faithful replica of any one mission — it’s more a blend of greatest hits from the designs of several — it really looks like Savage could step into a spacecraft at any moment.

“The whole point of the Mercury program … was to figure out how to safely get people into space and what would happen to them,” Savage says in a new video, which you can see below.

“So every single time they came down from a Mercury mission they [the astronauts] would talk to the engineers and spend weeks in meetings going ‘Okay, I couldn’t move my arm this way. I couldn’t hit this switch in this way. I couldn’t turn my head.”

As if that isn’t cool enough, Savage also is sporting an Apollo flight jacket replica that is advertised as being pretty darn close to the original. Check out Adam Savage’s Tested blog for amazing photos as well as a more complete video (for premium members.)

Mercury was the first American spaceflight program, and had six flights between 1961 and 1963. For more information about the Mercury spacesuit, check out this chapter from NASA book “This New Ocean: A History of Project Mercury“. You can also see a photo gallery of different Mercury suits.

Coincidentally, there’s a travelling exhibit on about the history of spacesuits, which Universe Today’s David Dickinson wrote about last week.

Mythbusters' Adam Savage (left) in front of a replica Mercury spacesuit. Credit: Tested/YouTube (screenshot) — Mythbusters’ Adam Savage (left) in front of a replica Mercury spacesuit. Credit: Tested/YouTube (screenshot)

A close-up of a Mercury replica spacesuit ordered by Mythbusters' Adam Savage. Credit: Tested/YouTube (screenshot) — A close-up of a Mercury replica spacesuit ordered by Mythbusters’ Adam Savage. Credit: Tested/YouTube (screenshot)

February 10, 2014December 23, 2015 by Elizabeth Howell

50 Years After Taking Over Earth, The Beatles’ Space Invasion Is Well Underway

Credit: Inside Science News Service and Amanda Page

As the Beatles strummed the opening notes to “All My Loving” on the Ed Sullivan Show 50 years ago yesterday, few could have imagined how wide-ranging that music would be. The broadcast gave birth to a global music phenomenon. And like all TV broadcasts of the day, the music carried out into space at the speed of light.

The Inside Science infographic above (see below for the full version) traces the history of the Beatles in relation to how far the broadcast travelled in that time. While those waves were washing out, er, across the universe, the Beatles have been taking over human space exploration in other ways. Below the jump are seven of the more memorable moments.

Rocking The Space Station With ‘Back at the ISS’

Technically speaking, this isn’t the Beatles, but it sure was inspired by them. ‘Back at the ISS’ — the remake of ‘Back in the U.S.S.R.’ by Dutch band Love & Mersey — is about a billion shades of awesome. Not only because of the lyrics, not only because of the high-energy space-themed video, but also because they sang in three languages. The song was released in March 2012 as a “rocking musical greeting” to Andre Kuipers (a European Space Agency astronaut) and the rest of the Expedition 30 crew days before the docking of the Automated Transfer Vehicle Edoardo Amaldi that month.

Beatles In The Sky With … Asteroids

Yup, there’s an asteroid named after the Beatles. Oh yeah, there are also asteroids named after members John Lennon, Paul McCartney, George Harrison and Ringo Starr.

Good Morning Good Morning wake-up calls

The Beatles have been used to wake up several shuttle crews, and also the Curiosity rover. Explained Eric Blood, Curiosity’s surface systems engineer: “She tends to be less cranky with a good wakeup song.”

Playing (And Drinking?) English Tea In Space

Here’s Paul McCartney in 2005 casually playing two tunes to the Expedition 12 crew — NASA astronaut Bill McArthur and Russian cosmonaut Valery Tokarev — during a live concert. It’s a bit hard to tell who had bigger stars in their eyes after the experience. “I told the audience ‘I think I need about 20 minutes to go have a lie down,’ McCartney stated in a NASA release from the time. “What do you do after that? We haven’t stopped talking about it since.”

Roll Over Beethoven: How The Beatles Almost Made Voyager’s ‘Golden Record’

Remember when scientists announced last year that Voyager 1 entered interstellar space? On board the spacecraft was a Golden Record intended to give aliens a glimpse into what Earth’s life is like. Included were songs from artists ranging from Bach to Blind Willie Johnson, but not the Beatles. They were almost included, though, as astronomer Carl Sagan (who chaired the selection committee) explained in his 1978 book Murmers of Earth. “We wanted to send ‘Here Comes The Sun’ by the Beatles, and all four Beatles gave their approval. But the Beatles did not own the copyright, and the legal status of the piece seemed too murky to risk,” he wrote.

Joining Mr. Mercury’s Light

There are so many earthly memorials to John Lennon after the singer’s untimely death in 1980, but late last year he got an extraterrestrial honor. Lennon was among 10 names approved for craters on the planet Mercury. “It’s unlikely that Mercury’s surface is populated with tangerine trees and marmalade skies, but the famous British musician who coined that phrase now has a physical presence on the planet closest to the Sun,” NASA said.

Sending Love To The Aliens With Jai Guru Deva Om

February 4, 2008 marked the first time NASA beamed any song into deep space, and what better choice than “Across The Universe”? The date marked the 40th anniversary of when the Beatles recorded the song, and came around the same time as the 45th anniversary of NASA’s Deep Space Network and the 50th anniversary of NASA’s first satellite, Explorer 1, among other milestones. In a statement, McCartney asked to “send my love to the aliens.”

What Beatles milestones in space have we missed? Let us know in the comments.

February 5, 2014December 23, 2015 by Ken Kremer

Mariner 10: Best Venus Image and 1st Ever Planetary Gravity Assist – 40 Years Ago Today

On Feb. 5, 1974, NASA's Mariner 10 mission took this first close-up photo of Venus during 1st gravity assist flyby. Credit: NASA

Exactly 40 Years ago today on Feb. 5, 1974, Mariner 10, accomplished a history making and groundbreaking feat when the NASA science probe became the first spacecraft ever to test out and execute the technique known as a planetary gravity assisted flyby used to alter its speed and trajectory – in order to reach another celestial body.

Mariner 10 flew by Venus 40 years ago to enable the probe to gain enough speed and alter its flight path to eventually become humanity’s first spacecraft to reach the planet Mercury, closest to our Sun.

Indeed it was the first spacecraft to visit two planets.

During the flyby precisely four decades ago, Mariner 10 snapped its 1st close up view of Venus – see above.

From that moment forward, gravity assisted slingshot maneuvers became an extremely important technique used numerous times by NASA to carry out planetary exploration missions that would not otherwise have been possible.

For example, NASA’s twin Voyager 1 and 2 probes launched barely three years later in 1977 used the gravity speed boost to conduct their own historic flyby expeditions to our Solar Systems outer planets.

Mariner 10's Mercury. This is a photomosaic of images collected by Mariner 10 as it flew past Mercury on 29 March 1974. It shows the southern hemisphere. The spacecraft took more than 7,000 images of Mercury, Venus, the Earth, and the moon during its mission. Credit: NASA — Mariner 10’s Mercury.
This is a photomosaic of images collected by Mariner 10 as it flew past Mercury on 29 March 1974. It shows the southern hemisphere. The spacecraft took more than 7,000 images of Mercury, Venus, the Earth, and the moon during its mission. Credit: NASA

Without the flyby’s, the rocket launchers thrust by themselves did not provide sufficient interplanetary speed to reach their follow on targets.

NASA’s Juno Jupiter orbiter just flew back around Earth this past October 9, 2013 to gain the speed it requires to reach the Jovian system.

The Mariner 10 probe used an ultraviolet filter in its imaging system to bring out details in the Venusian clouds which are otherwise featureless to the human eye – as you’ll notice when viewing it through a telescope.

Venus surface is completely obscured by a thick layer of carbon dioxide clouds.

The hellish planet’s surface temperature is 460 degrees Celsius or 900 degrees Fahrenheit.

Diagram of Mariner 10 which flew by Venus and Mercury in 1974 and 1975. This photo identifies various parts of the spacecraft and the science instruments, which were used to study the atmospheric, surface, and physical characteristics of Venus and Mercury. This was the sixth in the series of Mariner spacecraft that explored the inner planets beginning in 1962. Credit: Jet Propulsion Laboratory

Following the completely successful Venus flyby, Mariner 10 eventually went on to conduct a trio of flyby’s of Mercury in 1974 and 1975.

It imaged nearly half of the planets moon-like surface, found surprising evidence of a magnetic field, discovered that a metallic core comprised nearly 80 percent of the planet’s mass, and measured temperatures ranging from 187°C on the dayside to minus 183°C on the nightside.

Mercury was not visited again for over three decades until NASA’s MESSENGER flew by and eventually orbited the planet – and where it remains active today.

Mariner 10 was launched on Nov. 3, 1973 from the Kennedy Space Center atop an Atlas-Centaur rocket.

Mosaic of the Earth from Mariner 10 after launch. Credit: NASA

Shortly after blastoff if also took photos of the Earth and the Moon.

Ultimately it was the last of NASA’s venerable Mariner planetary missions hailing from the dawn of the Space Age.

Mariner 11 and 12 were descoped due to congressional budget cuts and eventually renamed as Voyager 1 and 2.

The Mariner 10 science team was led by Bruce Murray of the Jet Propulsion Laboratory (JPL), Pasadena, Calif.

Murray eventually became the Director of JPL. After he passed away in 2013, key science features on Martian mountain climbing destinations were named in his honor by the Opportunity and Curiosity Mars rover science teams.

Stay tuned here for Ken’s continuing LADEE, Chang’e-3, Orion, Orbital Sciences, SpaceX, commercial space, Mars rover and more planetary and human spaceflight news.

Ken Kremer