The Earth from the Moon – by Chang’e-3 on Christmas Day
Lander camera snapped this image on Christmas Day 2013. Credit: Chinese Academy of Sciences[/caption]
Nearly a month after the stunningly successful soft landing on the Moon by China’s first lunar mission on Dec. 14, 2013, the Chinese Academy of Sciences has at last released far higher quality digital imagery snapped by the Chang’e-3 lander and Yutu moon rover.
This release of improved images is long overdue.
And perhaps the best news of all involves a belated Christmas present to humanity – the publication of never before seen and absolutely stunning images of the Earth from the Moon captured by the lander on Christmas Day 2013.
We haven’t seen the Earth from the Moon’s surface in 4 decades – not since the 1970’s.
Until now, most of the Chang’e-3 mission images we’ve seen have essentially been rather low resolution pictures of pictures – that is screenshots or photos taken of the imagery that has been flashed onto large projection screens at the Beijing Aerospace Control Center, and then distributed by Chinese government media outlets.
So they have been degraded several times over.
I’ve collected a gallery of the new Chang’e-3 lunar photos here for all to enjoy – see above and below.
The gallery includes photos taken during the final moments of the descent and landing on Dec. 14, 2013, as well as portraits and 360 degree moonscape panoramas taken by both spacecraft after Yutu rolled its wheels onto the loose lunar soil 7 hours later on Dec. 15, and the fabulous new images of Earth in visible and UV light.
Yutu and the lander are about to awaken from their self induced slumber which began at Christmas time to coincide with the dawn of the the utterly frigid two week long lunar night.
Temperatures plunged to below minus 180 degrees Celsius.
They went to sleep to conserve energy since there is no sunlight to generate power with the solar arrays.
After driving off the lander, Yutu – which means ‘Jade Rabbit’ – drove in a semicircle around the lander and headed south.
Jade Rabbit stopped at 5 designated places.
The pair of Chinese spacecraft then snapped images of one another at each location. Some of those images were included in this new batch.
So you can see the lander from 3 different perspectives collected here:
Here’s a pair of very cool 360 degree panoramas – taken by each spacecraft and showing the other.
Finally here’s imagery taken during the landing sequence by the descent imager in the final minutes before touchdown at Mare Imbrium, nearby the Bay of Rainbows, or Sinus Iridum region.
It is located in the upper left portion of the moon as seen from Earth. You can easily see the landing site with your own eyes.
And be sure to check my earlier story with an eye popping astronauts eye view video combining all the descent imagery – here.
The landmark Chang’e-3 mission marks the first time that China has sent a spacecraft to touchdown on the surface of an extraterrestrial body.
China is only the 3rd country in the world to successfully soft land a spacecraft on Earth’s nearest neighbor after the United States and the Soviet Union.
Stay tuned here for Ken’s continuing Chang’e-3, Orbital Sciences, SpaceX, commercial space, LADEE, Mars and more news.
Curiosity Celebrates 500 Sols on Mars on Jan. 1, 2014
NASA’s Curiosity rover snaps fabulous new mosaic spying towering Mount Sharp destination looming dead ahead with her high resolution color cameras, in this cropped view. See full mosaic below. Imagery assembled from Mastcam raw images taken on Dec. 26, 2013 (Sol 494).
Credit: NASA/JPL/MSSS/Marco Di Lorenzo/Ken Kremer- kenkremer.com
Story updated[/caption]
Today, New Year’s Day 2014, NASA’s Curiosity mega rover celebrates a huge mission milestone – her 500th Martian Day on the Red Planet since the death defying touchdown of August 2012.
“500 Sols of Mars: While Earth celebrates #NewYear2014, midnight on Mars mark my 500th day of operations,” she tweeted today.
And Curiosity marked the grand occasion by snapping a fabulous new panorama spying towering Mount Sharp – looming dead ahead in her high resolution color cameras.
You can take in the magnificent Martian view Curiosity sees today – via our newly assembled mosaic of humongous Mount Sharp rising 5.5 kilometers (3.4 mi) into the Red Planets sky; see above and below.
Ascending mysterious Mount Sharp – which dominates the Gale Crater landing site – is the ultimate reason for Curiosity’s being.
NASA’s science and engineering teams dispatched the state-of-the-art robot there because they believe the lower sedimentary layers hold the clues to the time period when Mars was habitable eons ago and they possess the required chemical ingredients necessary to sustain microbial life.
But first she needs to reach the mountains foothills.
So, just like some Earthlings, Curiosity also set a New Year’s resolution she’d like to share with you all – just tweeted all the way from the Red Planet.
“Goals for 2014: Finish driving to Mars’ Mount Sharp & do all the science I can.”
Part of those goals involve shifting the missions focus to include the search for organic molecules – the building blocks of life as we know it – which may be preserved in the sedimentary rock layers.
“Really what we’re doing is turning the corner from a mission that is dedicated to the search for habitable environments to a mission that is now dedicated to the search for that subset of habitable environments which also preserves organic carbon,” Curiosity Principal Investigator John Grotzinger, of the California Institute of Technology in Pasadena, said recently at the Dec. 2013 annual meeting of the American Geophysical Union (AGU).
The 1 ton behemoth is in the midst of an epic trek to destination Mount Sharp, roving across 10 kilometers (6 mi.) of the rather rocky crater floor of her landing site inside Gale Crater.
But the alien crater floor strewn with a plethora of sharp edged rocks is ripping significant sized holes and causing numerous dents in several of the rovers six big aluminum wheels – as outlined in my prior report; here.
“Routes to future destinations for the mission may be charted to lessen the amount of travel over such rough terrain, compared to smoother ground nearby,” says NASA.
So far Curiosity’s odometer stands at 4.6 kilometers, following a post Christmas drive on Dec. 26, 2013 (Sol 494) after 16 months roving the Red Planet.
Curiosity’s handlers will be diligently watching the wear and tear on the 20 inch diameter wheels. She needs to rove along a smoother path forward to minimize wheel damage by sharp rocks.
Here’s our latest wheel mosaic from Dec. 26, 2013 (Sol 494) showing a several centimeter wide puncture in the left front wheel, which seems to have suffered the most damage.
The Mount Sharp and wheel mosaics were assembled by the imaging team of Marco Di Lorenzo and Ken Kremer.
“Taking stock this holiday season. I’m planning smoother paths for the new year,” Curiosity tweeted.
The team hopes the intrepid robot arrives at the base of Mount Sharp around the middle of this new year 2014, if all goes well.
Shortly thereafter the robot begins a new phase with the dramatic ascent up the chosen entryway which the team dubs the ‘Murray Buttes’ – fittingly named in honor of Bruce Murray, a Caltech planetary geologist, who worked on science teams of NASA’s earliest missions to Mars in the 1960s and ’70s.
Murray also was the director of NASA’s Jet Propulsion Laboratory from 1976 to 1982 and co-founded the Planetary Society in 1980. He passed away on Aug. 29, 2013.
“Bruce Murray contributed both scientific insight and leadership that laid the groundwork for interplanetary missions such as robotic missions to Mars, including the Mars rovers, part of America’s inspirational accomplishments. It is fitting that the rover teams have chosen his name for significant landmarks on their expeditions,” said NASA Mars Exploration Program Manager Fuk Li, of NASA’s Jet Propulsion Laboratory (JPL) , Pasadena, Calif.
Curiosity has already accomplished her primary goal of discovering a habitable zone on Mars that could support Martian microbes if they ever existed.
NASA’s rover Curiosity uncovered evidence that an ancient Martian lake had the right chemical ingredients, including clay minerals that could have sustained microbial life forms for long periods of time – and that these habitable conditions persisted on the Red Planet until a more recent epoch than previously thought.
1st Chang’e-3 Lunar Panorama
Portion of 1st panorama around Chang’e-3 landing site showing China’s Yutu rover leaving tracks in the lunar soil as it drives across the Moon’s surface on Dec. 15, 2013. Images taken by Chang’e-3 lander following Dec. 14 touchdown. Panoramic view was created from screen shots of a news video assembled into a mosaic.
Credit: CNSA/CCTV/screenshot mosaics & processing by Marco Di Lorenzo/Ken Kremer
See below robotic arm screenshots – – Story updated [/caption]
As night fell on the Earth’s Moon, China’s Yutu rover and mothership lander have both entered a state of hibernation determined to survive the frigidly harsh lunar night upon the magnificently desolate gray plains.
Yutu went to sleep at 5:23 a.m. Dec. 26, Beijing time, upon a command sent by mission control at the Beijing Aerospace Control Center (BACC), according to China’s State Administration of Science, Technology and Industry for National Defence (SASTIND).
The Chang’e-3 lander began its long nap hours earlier at 11:00 a.m. Beijing time on Christmas Day, Dec. 25.
The vehicles must now endure the lunar night, which spans 14 Earth days in length, as well as the utterly low temperatures which plunge to below minus 180 degrees Celsius.
Scientists completed a series of engineering tests on the probes to ensure they were ready to withstand the steep temperature drop, said Wu Fenglei of the Beijing Aerospace Control Center, to the Xinhua state news agency.
Since there is no sunlight, the solar panels can’t provide any power and have been folded back.
So they face a massive engineering challenge to endure the extremely cold lunar night.
Therefore in order to survive the frigid lunar environment, a radioisotopic heat source is onboard to provide heat to safeguard the rovers and landers delicate computer and electronics subsystems via the thermal control system.
They are situated inside a warmed box below the deck that must be maintained at a minimum temperature of about minus 40 degrees Celsius to prevent debilitating damage.
So the two spacecraft still have to prove they can hibernate and eventually emerge intact from the unforgiving lunar night.
Just prior to going to sleep, the 140 kg Yutu rover flexed its robotic arm and Chinese space engineers at BACC completed an initial assessment testing its joints and control mechanisms.
The short robotic arm appears similar in form and function to the one on NASA’s famous Spirit and OpportunityMars rovers.
It is equipped with an alpha particle X-ray instrument (APXS) – on the terminus – to determine the composition of lunar rocks and soil.
The robotic pair of spacecraft safely soft landed on the Moon on Dec. 14 at Mare Imbrium, nearby the Bay of Rainbows, or Sinus Iridum region. It is located in the upper left portion of the moon as seen from Earth. You can easily see the landing site with your own eyes.
Barely seven hours after the history making touchdown, ‘Yutu’ was painstakingly lowered from its perch atop the lander and then successfully drove all six wheels onto the moon’s surface on Dec. 15.
Yutu left noticeable tracks behind, several centimeters deep, as the wheels cut into the loose lunar regolith.
The Chang’e-3 lander and rover then conducted an initial survey of the stark lunar landing site, pockmarked with craters and small boulders.
They took an initial pair of portraits of one another. Read my earlier report – here.
The four legged lunar lander also snapped the missions first panoramic view of the touchdown spot at Mare Imbrium using three panoramic cameras (Pancams) pointing in different directions. Read my earlier report – here.
See the eerie panoramic view of the landing site showing Yutu’s first moments on the alien lunar surface in our screenshot mosaic above – and here.
See the dramatic video with an astronauts eye view of the lunar descent and touchdown in my prior story – here.
Yutu, which translates as ‘Jade Rabbit’, was then directed to travel in a semicircular path around the right side of the lander and is heading to the south.
Its currently napping about 40 meters to the south.
‘Jade Rabbit’ will resume the lunar trek upon awakening, along with the stationary lander, from their extended two week slumber around Jan 12, 2014.
Yutu will depart the Chang’e-3 landing zone forever and rove the moon’s surface for investigations expected to last at least 3 months – and perhaps longer depending on its robustness in the unforgiving space environment.
The robotic rover will use its suite of four science instruments to survey the moon’s geological structure and composition to locate the moon’s natural resources for use by potential future Chinese astronauts, perhaps a decade from now.
NASA’s Lunar Reconnaissance Orbiter (LRO) imaged the Chang’e-3 landing site in western Mare Imbrium around Christmas time on 24 and 25 December with its high resolution LROC camera and we’ll feature them here when available.
China is only the 3rd country in the world to successfully soft land a spacecraft on Earth’s nearest neighbor after the United States and the Soviet Union.
The best is surely yet to come!
Stay tuned here for Ken’s continuing Chang’e-3, LADEE, MAVEN, MOM, Mars rover and more news.
China’s 1st Moon rover ‘Yutu’ embarks on thrilling adventure marking humanity’s first lunar surface visit in nearly four decades. Yutu portrait taken by the Chang’e-3 lander. Credit: CNSA/CCTV
See below Yutu’s departing portrait of Chang’e-3 lander emblazoned with Chinese national flag Story updated[/caption]
China’s now famous ‘Yutu’ moon rover has set sail for what promises to be breathtaking new adventures on Earth’s nearest neighbor, after completing a final joint portrait session with the Chang’e-3 lander that safely deposited her on the lunar surface only a week ago.
Yutu’s upcoming journey marks humanity’s first lunar surface visit in nearly four decades since the Soviet Union’s Luna 24 sample return vehicle visited. America’s last lunar landing mission with the Apollo 17 astronauts departed 41 years ago on Dec. 14, 1972.
The Chang’e-3 mothership and Yutu rover have resumed full operations after awakening from a sort of self induced slumber following commands from Mission Control back in Beijing.
The lander and rover finished up their 5th and final dual picture taking session – in living lunar color – on Sunday, Dec. 22, according to CCTV, China’s state run broadcast network.
“Ten pictures have been taken at five spots so far, and all of them are better than we expected,” said Wu Weiren, chief designer of the China Lunar Probe Program, to CCTV.
See the newly released portraits from photo session 5 – above and below.
After arriving on the moon, Yutu and the lander took an initial pair of portraits of one another. Read my earlier report – here.
Yutu was then directed to travel in a semicircular path around the lander and to the south, making tracks several centimeters deep into the loose lunar regolith.
But within two days of the historic Dec. 14 touchdown, the two spacecraft took a four-day break that lasted from Dec. 16 to Dec. 20, during which China’s space engineers shut down their subsystems, according to China’s State Administration of Science, Technology and Industry for National Defense (SASTIND).
The vehicles took a ‘nap” to deal with direct solar radiation that significantly raised their temperatures. Yutu’s sunny side exceeded 100 degrees centigrade while the shaded side was simultaneously below zero, reported SASTIND.
“The break had been planned to last until Dec. 23, but the scientists decided to restart Yutu now for more research time, based on the recent observations and telemetry parameters,” said Pei Zhaoyu, spokesman for the Chinese lunar program, according to China’s Xinhua state news agency.
Both robots then snapped additional photos of one another during the traverse from each of five specific and preplanned locations.
See accompanying traverse map below – written in Chinese.
These images taken by Yutu were designed to show the 1200 kg Chang’e-3 lander from the front, side and back sides as it drove around the right side – for better illumination – at a distance of about 10 meters.
The final image of the Chang’e-3 lander taken by Yutu also captured China’s national flag emblazoned on the lander for the first time, since this was the first time it was in view of the rover’s camera eyes.
See the accompanying traverse graphic here – written in Chinese.
Having fulfilled the last of their joint tasks, the two spacecraft can therefore each begin their own lunar exploration missions, working independently of one another exactly as planned from the outset of China’s inaugural moon landing feat.
Yutu will depart the Chang’e-3 landing zone forever and begin its own lunar trek that’s expected to last at least 3 months – and perhaps longer if it’s delicate electronic components survive the moon’s utterly harsh and unforgiving space environment.
“They will begin to conduct scientific explorations of the geography and geomorphology of the landing spot and nearby areas, and materials like minerals and elements there. We will also explore areas 30 meters and 100 meters beneath the lunar soil. The exploration will continue longer than we planned, because all the instruments and equipments are working very well,” noted Wu Weiren.
The robotic pair of spacecraft safely soft landed on the Moon on Dec. 14 at Mare Imbrium, nearby the Bay of Rainbows, or Sinus Iridum region.
Barely seven hours after the history making touchdown, ‘Yutu’ was painstakingly lowered from its perch atop the lander and then successfully drove all six wheels onto the moon’s surface on Dec. 15.
The Chang’e-3 mothership captured a panoramic view of the stark lunar terrain surrounding the spacecraft after ‘Yutu’ drove some 9 meters away from the lander.
See the eerie panoramic view of the landing site showing Yutu’s first moments on the alien lunar surface in my prior story – here.
See the dramatic video with an astronauts eye view of the lunar descent and touchdown in my prior story – here.
The 120 kg Yutu rover is almost the size of a golf cart. It measures about 1.5 m x 1 m on its sides and stands about 1.5 m (nearly 5 feet) tall – virtually human height.
Yutu, which translates as ‘Jade Rabbit’ will use its suite of four science instruments to survey the moon’s geological structure and composition to locate the moon’s natural resources for use by potential future Chinese astronauts, perhaps a decade from now.
Stay tuned here for Ken’s continuing Chang’e-3, LADEE, MAVEN, MOM, Mars rover and more news.
Portion of 1st panorama around Chang’e-3 landing site after China’s Yutu rover drove onto the Moon’s surface on Dec. 15, 2013. The images were taken by Chang’e-3 lander following Dec. 14 touchdown. Panoramic view was created from screen shots of a news video assembled into a mosaic. Credit: CNSA/CCTV/screenshot mosaics & processing by Marco Di Lorenzo/Ken Kremer
See the complete panorama below Story updated[/caption]
China’s inaugural Chang’e-3 lunar lander has snapped the missions first panoramic view of the touchdown spot at Mare Imbrium.
To make it easier to see and sense ‘the new view from the Moon’, we have created screen shots from the rather low resolution TV broadcast and assembled them into a photo mosaic of the landing site – see above and below mosaics by Marco Di Lorenzo and Ken Kremer.
The Chang’e-3 mothership imaged the stark lunar terrain surrounding the spacecraft after the ‘Yutu’ rover perched atop successfully drove all six wheels onto the moon’s surface on Dec. 15, barely 7 hours after the momentous landing on Dec. 14.
The individual images were taken by three cameras positioned around the robotic lander.
Chinese scientists then pieced them together to form the lander’s first panoramic view of the lunar surface, according to CCTV.
“This picture is made of 60 pictures taken 3 times by the rover. The rover used three angles: vertical, 15 degrees tilted up, and 15 degrees down…so that we get an even farther view,” said Liu Enhai, Designer in Chief, Chang’E-3 Probe System, in a CCTV interview
The panoramic view shows ‘Yutu’ and its wheel tracks cutting a semi circular path at least several centimeters deep into the loose lunar regolith at the landing site at Mare Imbrium, located near the Bay of Rainbows.
A significant sized crater, several meters wide, is seen off to the left of Yutu and located only about 10 meters away from the Chang’e-3 lander.
Several more craters are visible in the pockmarked surface around the lander.
Mission leaders purposely equipped the lander with terrain recognition radar and software so that it could steer clear of hazards like craters and large boulders and find a safe spot to land.
Indeed just prior to touchdown, the lander actually hovered at an altitude of 100 meters for about 20 seconds to avoid the craters and rock fields which could have doomed the mission in its final moments.
See the dramatic Chang’e-3 landing video in my earlier report – here.
Here is our annotated screen shot from the landing video showing the eventual landing site in the distance:
“The rover reached the point of X after it went down from the lander, then it established contact with the ground. Then it went to point A, where the rover and lander took pictures of each other. Then it reached point B, where it’s standing now.” said Liu Jianjun, Deputy Chief Designer, Chang’E-3 Ground System, to CCTV.
China thus became only the 3rd country in the world to successfully soft land a spacecraft on Earth’s nearest neighbor after the United States and the Soviet Union.
Chinese President Xi Jinping and space agency leaders have hailed the Chang’e-3 mission as a complete success for China.
The Yutu rover, which translates as ‘Jade Rabbit’ will use its science instruments to survey the moon’s geological structure and composition on a minimum three month mission to locate the moon’s natural resources for use by potential future Chinese astronauts.
The lander will conduct in-situ exploration at the landing site for at least one year, say Chinese officials.
Hopefully, China will quickly start releasing full resolution imagery and video taken by the Chang’e-3 lander and Yutu rover at a dedicated mission website, like NASA does, rather than issuing photos of imagery from projection screens and televisions – so that we all can grasp the full beauty of their tremendous lunar feat.
Stay tuned here for Ken’s continuing Chang’e-3, LADEE, MAVEN, MOM, Mars rover and more news.
This screen shot from one photo of many of the moons surface snapped by the on-board descent imaging camera of the Chinese lunar probe Chang’e-3 on Dec. 14, 2013 shows the probe approaching the Montes Recti mountain ridge and approximate location of the landing site in Mare Imbrium. This marks the first time that China has sent a spacecraft to soft land on the surface of an extraterrestrial body. Image and video rotated 180 degrees.
Credit: Xinhua/CCTV/post processing and annotations Marco Di Lorenzo /Ken Kremer See the entire stunning Chang’e-3 lunar landing video – below
Story updated
[/caption]
China accomplished a major technological and scientific feat when the country’s ambitious Chang’e-3 robotic spacecraft successfully soft landed on the Moon on Dec. 14 – on their very first attempt to conduct a landing on an extraterrestrial body.
Along the way the descent imaging camera aboard the Chang’e-3 lander was furiously snapping photos during the last minutes of the computer guided descent.
For a firsthand look at all the thrilling action, be sure to check out the stunning landing video, below, which gives an astronauts eye view of the dramatic descent and touchdown by China’s inaugural lunar lander and rover mission.
The video was produced from a compilation of descent camera imagery. The version here has been rotated 180 degrees – so you don’t have to flip yourself over to enjoy the ride.
And it truly harkens back to the glory days of NASA’s manned Apollo lunar landing program of the 1960’s and 1970’s.
The dramatic Chang’e-3 soft landing took place at Mare Imbrium at 8:11 am EST, 9:11 p.m. Beijing local time, 1311 GMT, which is to the east of the announced landing site on the lava filled plains of the Bay of Rainbows, or Sinus Iridum region.
The precise landing coordinates were 44.1260°N and 19.5014°W -located below the Montes Recti mountain ridge and about 40 kilometers south of the 6 kilometer diameter crater known as Laplace F – see image below.
The video begins as Chang’e-3 is approaching the Montes Recti mountain ridge which is about 90 km in length. Its peaks rise to nearly 2 km.
Chang’e-3 carried out the rocket powered descent to the Moon’s surface by firing the landing thrusters starting at the altitude of 15 km (9 mi) for a soft landing targeted to a preselected area in Mare Imbrium.
The vehicles thrusters then fire to pivot the lander towards the surface at about the 2:40 minute mark when it’s at an altitude of roughly 3 km.
The powered descent was autonomous and preprogrammed and controlled by the probe itself, not by mission controllers on Earth stationed at the Beijing Aerospace Control Center (BACC) in Beijing.
Altogether it took about 12 minutes using the variable thrust engine which can continuously vary its thrust power between 1,500 to 7,500 newtons.
The variable thrust engine enabled Chang’e-3 to reduce its deceleration as it approached the moons rugged surface.
The 1200 kg lander was equipped with unprecedented terrain recognition equipment and software to hover above the landing site and confirm it was safe before proceeding.
This enabled the craft to avoid hazardous rock and boulder fields as well as craters in the pockmarked terrain that could spell catastrophe even in the final seconds before touchdown, if the vehicle were to land directly on top of them.
The descent engine continued firing to lower the lander until it was hovering some 100 meters above the lunar surface – at about the 5:10 minute mark.
After hovering for about 20 seconds and determining it was safe to proceed, the lander descended further to about 3 meters. The engine then cut off and the lander free fell the remaining distance. The impact was cushioned by shock absorbers.
There is a noticeable dust cloud visible on impact as the Chang’e-3 mothership touched down atop the plains of Mare Imbrium.
Barely 7 hours later, China’s first ever lunar rover ‘Yutu’ rolled majestically down a pair of ramps and onto the Moon’s soil on Sunday, Dec. 15 at 4:35 a.m. Beijing local time.
The six wheeled ‘Yutu’, or Jade Rabbit, rover drove straight off the ramps and sped right into the history books as it left a noticeably deep pair of tire tracks behind in the loose lunar dirt.
The stunning feat was broadcast on China’s state run CCTV.
China thus became only the 3rd country in the world to successfully soft land a spacecraft on Earth’s nearest neighbor after the United States and the Soviet Union.
It’s been nearly four decades since the prior lunar landing was accomplished by the Soviet Union’s Luna 24 sample return spacecraft back in 1976.
America’s last visit to the Moon’s surface occurred with the manned Apollo 17 landing mission – crewed by astronauts Gene Cernan and Harrison ‘Jack’ Schmitt , who coincidentally ascended from the lunar soil on Dec. 14, 1972 – exactly 41 years ago.
China’s Chang’e-3 probe joins NASA’s newly arrived LADEE lunar probe which entered lunar orbit on Oct. 6 following a spectacular night time blastoff from NASA’s Wallops Flight Facility in Virginia.
Stay tuned here for Ken’s continuing Chang’e-3, LADEE, MAVEN, MOM, Mars rover and more news.
Last night I used my telescope to eye-hike the volcanic plains of the Sea of Rains (Mare Imbrium) where the Yutu rover and lander sit beneath a blistering sun. With no atmosphere to speak of and days that last two weeks, noontime temperatures can hit 250 degrees Fahrenheit (122 C) . That’s hot enough that mission control at the Beijing Aerospace Command and Control Centerhas decided to draw the shades and give the rover a nap from science duties until December 23 when things cool down a bit.
While studying the subtle gray hues of the Imbrium lava flows I got to wondering what the sky might look like if I could don a spacesuit and visit the landing site “where the skies are not cloudy all day” (to quote a famous song). With no atmosphere to speak of, stargazing can be done both day and night on the moon though I suspect it’s better at night when there’s less glare from your surroundings. Night, defined as the time from sunset to sunrise (no twilights here), lasts about 14.5 Earth days. Days are equally long.
From Yutu’s point of view, it’s very nearly lunar noon today (Dec. 19) with the sun halfway up in the southern sky. Looking at the map of the sky from the lander’s location, you’ll see a few familiar constellations and one very familiar planet – Earth!
Today Earth appears as a very thin crescent a short distance to the left or east of the sun. Because the moon takes just as long to rotate on its axis as it does to revolve around the Earth, the same face of the moon always faces our planet. Because the two are in synchrony, astronomers call it synchronous rotation.
From the perspective of someone standing on the moon, Earth stands still in one spot of sky throughout the 29.5 day lunar day-night cycle. Well, not perfectly still. Because the moon’s orbit is inclined about 5 degrees to Earth’s orbit and its speed varies along its non-circular orbit, Earth describes a little circle in the lunar sky about 10 degrees in diameter every four weeks.
As the sun slowly moves off to the west, our blue planet remains nearly stationary from Yutu’s perspective and undergoes all the familiar phases we see the moon experience back here on Earth: an evening crescent to start followed by a first quarter Earth, Full Earth last quarter and finally, New Earth. I like the ring of that last one.
Yutu and the lander will see the sun drift to the west while Earth moves east, rises higher in the lunar sky and putting on the pounds phase-wise. Today Earth’s glides across the border of Sagittarius into Capricornus. The next Full Earth happens on New Year’s Eve when the sun is directly opposite the Earth in the lunar sky.
Full Earth always happens around local midnight or about one week before sunrise during the long lunar day. On the moon the sun is up for about two weeks and then disappears below the horizon for another two weeks before rising again. At Full Earth time, the sun remains hidden around the lunar backside. When the nights are blackest, the bright ball of Earth spreads a welcome blue glow over the desolate landscape.
Things really get interesting during lunar eclipses when the moon moves behind the Earth into the planet’s shadow. The next one’s on April 15, 2014. Here on the ground we’ll see the moon gradually munched into by Earth’s shadow until totality, when sunlight from all the sunrises and sunsets around the rim of the planet are refracted by the atmosphere into the shadow, coloring the moon a coppery red.
Yutu will see just the opposite. Looking back toward the Earth from inside its shadow, the rover will witness a total eclipse of the sun by the Earth. If by some wonder the Chinese are able to photograph the event, we’ll see photos of the black ball of Earth rimmed in red fire from sunset and sunrise light refracted by our atmosphere. My interpretation using sky mapping software only hints at the wonder of the scene. Beijing Aerospace, if you’re reading this, please make it happen.
Earth eclipses the sun filmed by Japan’s Kaguya lunar orbiter. There are really two eclipses here – the Earth eclipsed by the limb of the moon at the video’s start followed by the solar eclipse.
On two other occasions, our robotic emissaries have photographed solar eclipses from Luna. NASA’s Surveyor 3 snapped a couple crude pictures of the April 24, 1967 eclipse from inside a crater in Mare Cognitium, the Sea that has Become Known. Japan’s orbiting Kaguya probe did the job much more eloquently on video during the February 9, 2009 penumbral lunar eclipse. In a penumbral eclipse (seen from Earth) the moon misses Earth’s dark inner shadow called the umbra, passing only through the outer penumbra, but because the Earth is three times larger than the sun (seen from the moon), it easily covered the sun completely in the complementary total solar eclipse.
And the best thing about watching eclipses from the moon? Guaranteed clear skies!