We often hear how the Moon’s appearance hasn’t changed in millions or even billions of years. While micrometeorites, cosmic rays and the solar wind slowly grind down lunar rocks, the Moon lacks erosional processes such as water, wind and lurching tectonic plates that can get the job done in a hurry.
Remember Buzz Aldrin’s photo of his boot print in the lunar regolith? It was thought the impression would last up to 2 million years. Now it seems that estimate may have to be revised based on photos taken by the Lunar Reconnaissance Orbiter (LRO) that reveal that impacts are transforming the surface much faster than previously thought.
The LRO’s high resolution camera, which can resolve features down to about 3 feet (1-meter) across, has been peering down at the Moon from orbit since 2009. Taking before and after images, called temporal pairs, scientists have identified 222 impact craters that formed over the past 7 years. The new craters range from 10 feet up to 141 feet (3-43 meters) in diameter.
By analyzing the number of new craters and their size, and the time between each temporal pair, a team of scientists from Arizona State University and Cornell estimated the current cratering rate on the Moon. The result, published in Nature this week, was unexpected: 33% more new craters with diameters of at least 30 feet (10 meters) were found than anticipated by previous cratering models.
Similar to the crater that appeared on March 17, 2013 (above), the team also found that new impacts are surrounded by light and dark reflectance patterns related to material ejected during crater formation. Many of the larger impact craters show up to four distinct bright or dark reflectance zones. Nearest to the impact site, there are usually zone of both high and low reflectance. These two zones likely formed as a layer of material that was ejected from the crater during the impact shot outward to about 2½ crater diameters from the rim.
From analyzing multiple impact sites, far flung ejecta patterns wrap around small obstacles like hills and crater rims, indicating the material was traveling nearly parallel to the ground. This kind of path is only possible if the material was ejected at very high speed around 10 miles per second or 36,000 miles per hour! The jet contains vaporized and molten rock that disturb the upper layer of lunar regolith, modifying its reflectance properties.
How LRO creates temporal pairs and scientists use them to discover changes on the moon’s surface.
In addition to discovering impact craters and their fascinating ejecta patterns, the scientists also observed a large number of small surface changes they call ‘splotches’ most likely caused by small, secondary impacts. Dense clusters of these splotches are found around new impact sites suggesting they may be secondary surface changes caused by material thrown out from a nearby primary impact. From 14,000 temporal pairs, the group identified over 47,000 splotches so far.
Based on estimates of size, depth and frequency of formation, the group estimated that the relentless churning caused by meteoroid impacts will turn over 99% of the lunar surface after about 81,000 years. Keep in mind, we’re talking about the upper regolith, not whole craters and mountain ranges. That’s more than 100 times faster than previous models that only took micrometeorites into account. Instead of millions of years for those astronaut boot prints and rover tracks to disappear, it now appears that they’ll be wiped clean in just tens of thousands!
On this date half a century ago the Soviet Luna 9 spacecraft made humanity’s first-ever soft landing on the surface of the Moon. Launched from Baikonur on Jan. 31, 1966, Luna 9 lander touched down within Oceanus Procellarum — somewhere in the neighborhood of 7.08°N, 64.37°E* — at 18:44:52 UTC on Feb. 3. The fourth successful mission in the USSR’s long-running Luna series, Luna 9 sent us our first views of the Moon’s surface from the surface and, perhaps even more importantly, confirmed that a landing by spacecraft was indeed possible.
The entire Luna 9 lander was made up of two main parts: a 1,439-kg flight/descent stage which contained retro-rockets and orientation engines, navigation systems, and various fuel tanks, and a 99-kg (218-lb) pressurized “automatic lunar station” that contained all the science and imaging instruments along with batteries, heaters, and a radio transmitter.
When a probe on the descent stage detected contact with the lunar surface, the spherical station — encased in an inflated airbag — was jettisoned to soft-land a safe distance away — after a bit of bouncing, of course; the lander hit the Moon’s surface at about 22 km/hr (13 mph)!
Once the airbag cushions deflated Luna 9, like a shiny metal flower, opened its four “petals,” extended its radio antennas and began taking panoramic television camera images of its surroundings, at the time lit by a very low Sun on the lunar horizon. Received on Earth early on Feb. 4, 1966, they were the first pictures taken from the surface of the Moon and in fact the first images acquired from the surface of another world.
Other missions, both Soviet and American, had captured close-up images of the Moon in previous years but Luna 9 was the first to soft-land (i.e., not crash land) and operate from the surface. The spacecraft continued transmitting image data to Earth until its batteries ran out on the night of Feb. 6, 1966. A total of four panoramas were acquired by Luna 9 over the course of three days, as well as data on radiation levels on the Moon’s surface (not to mention the valuable knowledge that a spacecraft wouldn’t just completely sink into the lunar regolith!)
Four months later, on June 2, 1966, NASA’s Surveyor 1 would become the first U.S. spacecraft to soft-land on the Moon. Surveyor 1 would send back science data and 11,240 photos over the course of a month in operation but, in terms of the space “race,” Luna 9 will always be remembered as first place winner.
*Or is it 7.14°N/60.36°W? Even today it’s still not precisely known where Luna 9 landed, but researchers at Arizona State University are actively searching through Lunar Reconnaissance Orbiter Camera pictures in an attempt to spot the “lost” spacecraft and/or evidence of its historic landing. Read more about that here.
NASA has just received a significant boost in the agency’s current budget after both chambers of Congress passed the $1.1 Trillion 2016 omnibus spending bill this morning, Friday, Dec. 18, which funds the US government through the remainder of Fiscal Year 2016.
Nearly 47 years ago, the crew of Apollo 8 took an image of planet Earth from the Moon that has been called “the most influential environmental photograph ever taken.” Called Earthrise, the picture represented the first time human eyes saw their homeworld come into view around another planetary body.
Sometimes, it seems to be a cosmic misfortune that we only get to view the universe from a singular vantage point.
Take the example of our single natural satellite. As the Moon waxes and wanes through its cycle of phases, we see the familiar face of the lunar nearside. This holds true from the day we’re born until the day we die. The Romans and Paleolithic man saw that same face, and until less than a century ago, it was anyone’s guess as to just what was on the other side.
Enter the Space Age and the possibility to finally get a peek at the universe from different perspective via our robotic ambassadors. This week, the folks over at NASA’s Scientific Visualization Studio released a unique video simulation that utilized data from NASA’s Lunar Reconnaissance Orbiter to give us a view unseen from Earth. This perspective shows just what the phases of the Moon would look like from the vantage point of the lunar farside:
You can see the Moon going through the synodic 29.5 day period a familiar phases, albeit with an unfamiliar face. Note that the Sun zips by, as the lunar farside wanes towards New. And in the background, the Earth can be seen, presenting an identical phase and tracing out a lazy figure eight as it appears and disappears behind the lunar limb.
What’s with the lunar-planetary game of peek-a-boo? Well, the point of view for the video assumes that your looking at down at the lunar farside from a stationary point above the Moon. Note that the disk of the Moon stays fixed in place. The Moon actually ‘rocks’ or nods back and forth and side-to-side in motions referred to as libration and nutation, and you’re seeing these expressed via the motion of the Earth in the video. This assures that we actually get a peek over the lunar limb and see a foreshadowed extra bit of the lunar farside, with grand 59% of the lunar surface visible from the Earth. Such is the wacky motion of our Moon, which gave early astronomers an excellent crash course in celestial mechanics 101.
Now, to dispel some commonly overheard lunar myths:
Myth #1: The moon doesn’t rotate. Yes, it’s tidally locked from our perspective, meaning that it keeps one face turned Earthward. But it does turn on its axis in lockstep as it does so once every 27.3 days, known as a sidereal month.
Myth #2: The Farside vs. the Darkside. (Cue Pink Floyd) We do in fact see the dark or nighttime side of the Moon just as much as the daytime side. Despite popular culture, the farside is only synonymous with the darkside of the Moon during Full phase.
Humanity got its first glimpse of the lunar farside in 1959, when the Soviet Union’s Luna 3 spacecraft looked back as it flew past the Moon and beamed us the first blurry image. The Russians got there first, which is why the lunar farside now possesses names for features such as the “Mare Moscoviense”.
Think we’ve explored the Moon? Thus far, no mission – crewed or otherwise – has landed on the lunar farside. The Apollo missions were restricted to nearside landing sites at low latitudes with direct line of sight communication with the Earth. The same goes for the lunar poles: the Moon is still a place begging for further exploration.
Why go to the lunar farside? Well, it would be a great place to do some radio astronomy, as you have the bulk of the Moon behind you to shield your sensitive searches from the now radio noisy Earth. Sure, the dilemmas of living on the lunar farside might forever outweigh the benefits, and abrasive lunar dust will definitely be a challenge to lunar living… perhaps an orbiting radio astronomy observatory in a Lissajous orbit at the L2 point would be a better bet?
And exploration of the Moon continues. Earlier this week, the LRO team released a finding suggesting that surface hydrogen may be more abundant on the poleward facing slopes of craters that litter the lunar south pole region. Locating caches of lunar ice in permanently shadowed craters will be key to a ‘living off of the land’ approach for future lunar colonists… and then there’s the idea to harvest helium-3 for nuclear fusion (remember the movie Moon?) that’s still science fiction… for now.
Perhaps the Moonbase Alpha of Space: 1999 never came to pass… but there’s always 2029!
NASA Administrator Charles Bolden formally announced the rollout of NASA’s FY 2016 budget request today during a “state of the agency” address at the Kennedy Space Center (KSC), back dropped by the three vehicles at the core of the agency’s human spaceflight exploration strategy; Orion, the Boeing CST-100 and the SpaceX Dragon.
“To further advance these plans and keep on moving forward on our journey to Mars, President Obama today is proposing an FY 2016 budget of $18.5 billion for NASA, building on the significant investments the administration has made in America’s space program over the past six years,” Administrator Bolden said to NASA workers and the media gathered at the KSC facility where Orion is being manufactured.
“These vehicles are not things just on paper anymore! This is tangible evidence of what you [NASA] have been doing these past few years.”
Bolden said the $18.5 Billion budget request will enable the continuation of core elements of NASA’s main programs including first launch of the new commercial crew vehicles to orbit in 2017, maintaining the Orion capsule and the Space Launch System (SLS) rocket to further NASA’s initiative to send ‘Humans to Mars’ in the 2030s, extending the International Space Station (ISS) into the next decade, and launching the James Webb Space Telescope in 2018. JWST is the long awaited successor to NASA’s Hubble Space Telescope.
“NASA is firmly on a journey to Mars. Make no mistake, this journey will help guide and define our generation.”
Funding is also provided to enable the manned Asteroid Redirect Mission (ARM) by around 2025, to continue development of the next Mars rover, and to continue formulation studies of a robotic mission to Jupiter’s icy moon Europa.
“That’s a half billion-dollar increase over last year’s enacted budget, and it is a clear vote of confidence in you – the employees of NASA – and the ambitious exploration program you are executing,” said Bolden.
Overall the additional $500 million for FY 2016 translates to a 2.7% increase over FY 2015. That compares to about a 6.4% proposed boost for the overall US Federal Budget amounting to $4 Trillion.
The Boeing CST-100 and the SpaceX Dragon V2 will restore the US capability to ferry astronauts to and from the International Space Station (ISS).
In September 2014, Bolden announced the selections of Boeing and SpaceX to continue development and certification of their proposed spaceships under NASA’s Commercial Crew Program (CCP) and Launch America initiative started back in 2010.
Since the retirement of the Space Shuttle program in 2011, all NASA astronauts have been totally dependent on Russia and their Soyuz capsule as the sole source provider for seats to the ISS.
“The commercial crew vehicles are absolutely critical to our journey to Mars, absolutely critical. SpaceX and Boeing have set up operations here on the Space Coast, bringing jobs, energy and excitement about the future with them. They will increase crew safety and drive down costs.”
CCP gets a hefty and needed increase from $805 Million in FY 2015 to $1.244 Billion in FY 2016.
To date the Congress has not fully funded the Administration’s CCP funding requests, since its inception in 2010.
The significant budget slashes amounting to 50% or more by Congress, have forced NASA to delay the first commercial crew flights of the private ‘space taxis’ from 2015 to 2017.
As a result, NASA has also been forced to continue paying the Russians for crew flights aboard the Soyuz that now cost over $70 million each under the latest contract signed with Roscosmos, the Russian Federal Space Agency.
Bolden has repeatedly stated that NASA’s overriding goal is to send astronauts to Mars in the 2030s.
To accomplish the ‘Journey to Mars’ NASA is developing the Orion deep space crew capsule and mammoth SLS rocket.
However, both programs had their budgets cut in the FY 2016 proposal compared to FY 2015. The 2015 combined total of $3.245 Billion is reduced in 2016 to $2.863 Billion, or over 10%.
The first test flight of an unmanned Orion atop the SLS is now slated for liftoff on Nov. 2018, following NASA’s announcement of a launch delay from the prior target of December 2017.
Since the Journey to Mars goal is already underfunded, significant cuts will hinder progress.
This comes despite the fact that the renowned robot just reached the summit of a Martian mountain at Cape Tribulation and is now less than 200 meters from a science goldmine of water altered minerals.
Funding for the Lunar Reconnaissance Orbiter (LRO) is also zeroed out in FY 2016.
Both missions continue to function quite well with very valuable science returns. They were also zeroed out in FY 2015 but received continued funding after a senior level science review.
So their ultimate fate is unknown at this time.
Overall, Bolden was very upbeat about NASA’s future.
“I can unequivocally say that the state of NASA is strong,” Bolden said.
He concluded his remarks saying:
“Because of the dedication and determination of each and every one of you in our NASA Family, America’s space program is not just alive, it is thriving! Together with our commercial and international partners, academia and entrepreneurs, we’re launching the future. With the continued support of the Administration, the Congress and the American people, we’ll all get there together.”
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
Ever wonder what your refrigerator’s impacting at the speed of a tank artillery shell would do to the Moon? The Lunar Reconnaissance Orbiter’s (LRO) primary camera has provided an image of just such an event when it located the impact site of another NASA spacecraft, the Lunar Atmosphere and Dust Environment Explorer (LADEE). The fridge-sized LADEE spacecraft completed its final Lunar orbit on April 18, 2014, and then crashed into the far side of the Moon. LADEE ground controllers were pretty certain where it crashed but no orbiter had found it until now. With billions of craters across the lunar surface, finding a fresh crater is a daunting task, but a new method of searching for fresh craters is what found LADEE.
The primary purpose of the LADEE mission was to search for lunar dust in the exceedingly thin atmosphere of the Moon. NASA Apollo astronauts had taken notes and drawings of incredible spires and rays of apparent dust above the horizon of the Moon as they were in orbit. To this day it remains a mystery although LADEE researchers are still working their data to find out more.
The LRO spacecraft has been in lunar orbit since 2007. With the LROC Narrow Angle Camera, LRO has the ability to resolve objects less than 2 feet across, and it was likely just a matter of finding time to snap and to search photos for a tiny impact crater.
However, the LROC team recently developed a new algorithm in software to search for fresh craters. Having a good idea where to begin the search, they decided to search for LADEE and quickly found it. The LROC team said the impact site is “about half a mile (780 meters) from the Sundman V crater rim with an altitude of about 8,497 feet (2,590 meters) and was only about two tenths of a mile (300 meters) north of the location mission controllers predicted based on tracking data.” Sundman Crater is about 200 km (125 miles) from a larger crater named Einstein.
The LADEE impact site is within 300 meters of the location estimated by the LADEE team. The ground control team at Ames Research Center knew the location very well within just hours after the time of the planned impact. They had to know LADEE’s location in orbit with split-second accuracy and also know very accurately the altitude of the terrain LADEE was skimming over. LADEE was traveling at 1699 meters per second (3,800 mph, 5,574 feet/sec) upon impact.
But still, finding something as small as this crater can be difficult.
Looking at these images, the scale of lunar morphology is very deceiving. Craters that are 10 meters in diameter can be mistaken for 100 meter or even 1000 meters. The first image and third images (below) in this article are showing only a small portion of the external slope of the eastern rim of Sundman V, the satellite crater to the southeast of crater Sundman. Sundman V is 19,000 meters in diameter (19 km, 11.8 miles) whereas the first image is only 223 meters across.
The following image, which is the ratioing of “before” and “after” impact images by LROC, clearly reveals the impact scar from LADEE. LADEE’s crater is only approximately 10 feet in diameter (3 m) with the ejecta fanning out 200 meters to the west by northwest. LADEE was traveling westward across the face of the Moon that we see from Earth, reached the western limb and finally encountered Sundman.
In the third image of this article (above), only a 1000 meter square view of the outer slope of Sundman V’s eastern rim is seen. Rather than take the difference between the two images, which is essentially what your eye-brain does with an image pair, LROC engineers take the ratio which effectively raises the contrast dramatically. Sundman V crater is on the far side of the Moon but very near the limb. At times, due to lunar libration, this site can be seen from the Earth. In the Lunar Orbiter image, below, Sundman and satellites J & V are marked. The red circle in the image below is the area in which LROC’s high resolution images reside. Furthermore, the famous Arizona meteor crater east of Flagstaff would also easily fit inside the circle.
The discovery so close to the predicted impact site confirmed how accurately the LADEE team could model the chaotic orbits around the Moon – at least during short intervals of time. Gravitationally, the Moon is truly like Swiss cheese. The effects of upwelling magma during its creation, the effects of the Earth’s tidal forces, and all the billions of asteroid impacts created a very chaotic gravitational field. Where the lunar surface is higher or more dense, gravity is stronger and vice-versa. LADEE struggled to maintain an orbit that would not run into the Moon. Without a constant vigil by Ames engineers, LADEE’s orbit would be shifted and rotated relative to the Moon’s surface until it eventually would intersect the Lunar surface – run into the Moon. Eventually, this had to happen as LADEE ran out of propulsion fuel.
The method used by the LROC team in its basic approach is by no means new. Clyde Tombaugh used a blink comparator to search for Planet X for several months and many frame pairs of the night sky. The comparator would essentially show one image and then a second of the same view taken a few nights apart to Clyde’s eye. Tombaugh’s eye and brain could process the two images and identify slight shifts of an object from one frame to the other. Stars are essentially fixed, don’t move but objects in our solar system do move in the night sky over hours or days. In the same way, the new software employed by LROC engineers takes two images and compares them mathematically. A human is replaced by a computer and software to weed out the slightest changes between a pair of images; images of the same area but spaced in time. Finding changes on the surface of a body such as the Moon or Mars is made especially difficult because of the slightest changes in lighting and location of the observer (the spacecraft). The new LROC software marks a new step forward in sophistication and thus has returned LADEE back to us.
The following Lunar Orbiter image from the 1960s is high contrast and reveals surface relief in much more detail. Einstein crater is clearly seen, as is Sundman with J and V satellite craters on its rim.
Wow, this doesn’t happen very often: Earth and Mars together in one photo. To make the image even more unique, it was taken from lunar orbit by the Lunar Reconnaissance Orbiter. This two-for-one photo was was acquired in a single shot on May 24, 2014, by the Narrow Angle Camera (NAC) on LRO as the spacecraft was turned to face the Earth, instead of its usual view of looking down at the Moon.
The LRO imaging team said seeing the planets together in one image makes the two worlds seem not so far apart, and that the Moon still might have a role to play in future exploration.
“The juxtaposition of Earth and Mars seen from the Moon is a poignant reminder that the Moon would make a convenient waypoint for explorers bound for the fourth planet and beyond!” said the LRO team on their website. “In the near-future, the Moon could serve as a test-bed for construction and resource utilization technologies. Longer-range plans may include the Moon as a resource depot or base of operations for interplanetary activities.”
Watch a video created from this image where it appears you are flying from the Earth to Mars:
The LROC team said this imaging sequence required a significant amount of planning, and that prior to the “conjunction” event, they took practice images of Mars to refine the timing and camera settings.
When the spacecraft captured this image, Earth was about 376,687 kilometers (234,062 miles) away from LRO and Mars was 112.5 million kilometers away. So, Mars was about 300 times farther from the Moon than the Earth.
The NAC is actually two cameras, and each NAC image is built from rows of pixels acquired one after another, and then the left and right images are stitched together to make a complete NAC pair. “If the spacecraft was not moving, the rows of pixels would image the same area over and over; it is the spacecraft motion, combined with fine-tuning of the camera exposure time, that enables the final image, such as this Earth-Mars view,” the LRO team explained.
Check out more about this image on the LRO website, which includes a zoomable, interactive version of the photo.
If you’re a fan of moon observation, it’s lucky for you that spacecraft such as the Lunar Reconnaissance Orbiter exist. For about the past five years, the NASA spacecraft has been in orbit around a closest large neighbor, taking images of the surface in high-definition.
To celebrate LRO’s fifth anniversary, NASA is asking members of the public to vote on which of those images (above) is their favorite. This isn’t so much a statement about the scientific data it has collected, NASA said, but more appreciating the images as art.
Voting runs from May 23 to June 6, and the winner will be announced with the full collection’s release on June 18 — the actual official fifth anniversary of the launch. You can find more information about the vote at this page.
By the way, LRO not only takes good pictures of the moon, but also of other spacecraft. You can check out its pictures of LADEE and Chang’e-3 in these past Universe Today articles.
Meanwhile, James Garvin — NASA’s chief scientist of the sciences and exploration directorate — eloquently weighs in below on his favorite images of the moon. His description of Aristarchus is interesting: “Here is Mother Nature’s expression of a gigantic landform made by a cosmic collision.” You can check out the other four below.
That’s Earth. That’s us. Way off in the distance as a fairly small, blue and swirly white sphere. This is the newest so-called “Earthrise” image, and it was taken on February 1, 2014 by the Lunar Reconnaissance Orbiter.
“LRO experiences twelve earthrises every day, however LROC is almost always busy imaging the lunar surface so only rarely does an opportunity arise such that LROC can capture a view of the Earth,” wrote LROC Principal Investigator Mark Robinson on the instrument’s website. “On the first of February of this year LRO pitched forward while approaching the north pole allowing the LROC WAC to capture the Earth rising above Rozhdestvenskiy crater (180-km diameter).”
Robinson went on to explain that the Earth is a color composite from several frames and the colors are very close to what the average person would see if they were looking back at Earth themselves from lunar orbit. “Also, in this image the relative brightness between the Earth and the Moon is correct, note how much brighter the Earth is relative to the Moon,” Robinson said.
Below is a gif image that demonstrates how images are combined over several orbits to create a full image from the Wide Angle Camera.
The frames were acquired at two second intervals, so the total time to collect the sequence was 5 minutes. The video is faster than reality by a factor of about 20.