Category Archives: LROC

A Square Corner

Did you ever notice just about every crater is at least a little rounded, some a bit elongated sure but rounded and most are just plain circular. Well “square” corners do occur and while they can be fodder for conspiracy theories, there are perfectly reasonable explanations for their formation.

The lunar crater above (NASA/GSFC/Arizona State University) is a good example. The name of the crater is Lavoisier, named for the famous French Chemist Antoine Lavoisier.

The crater is about 70 km across (42 miles), pretty large and can be seen with even a small telescope – yhe image width is only about 10 percent of the entire crater. The thing about Lavoisier is the location, Longitude: 81.253° West, Latitude: 38.169° North puts it on the northwestern limb so you need something steady to see it well. Yes binoculars would work but not for a decent examination. Plus the moon probably needs to be pretty well full. I will definitely have a look in a couple of weeks.

So how do we get to the squared off corners? Here’s what the LRO / NASA website had to say:

Continue reading

Giordano Bruno Crater

Here is a wonderful picture of the crater Giaordano Bruno taken by the LROC camera aboard the Lunar Reconnainse Orbiter.

The crater is about 22 x 22 km / 13 x 13 miles and is named for the Italian philospher born in 1548.

I also want to introduce you to a bit of software I have on every computer I own. The program is called the Virtual Moon Atlas. I have used this for YEARS and love it. Oh yes, the cost for this program is ZERO. Yes, free.

I like to pick out a crater on the moon (eyes to binocular to telescope size) and locate it on the Atlas and the wealth of information, well you have to try it. Or do the reverse pick out an crater on the Atlas and locate it.

Download it here at SourceForge and enjoy!

Strange Lunar Image – Meteor Hit


NASA/LRO (By Nancy Neal Jones
NASA’s Goddard Space Flight Center in Greenbelt, MD)- On Oct.13, 2014 something very strange happened to the camera aboard NASA’s Lunar Reconnaissance Orbiter (LRO). The Lunar Reconnaissance Orbiter Camera (LROC), which normally produces beautifully clear images of the lunar surface, produced an image that was wild and jittery. From the sudden and jagged pattern apparent in the image, the LROC team determined that the camera must have been hit by a tiny meteoroid, a small natural object in space.

LROC is a system of three cameras mounted on the LRO spacecraft. Two Narrow Angle Cameras (NACs) capture high resolution black and white images. The third Wide Angle Camera captures moderate resolution images using filters to provide information about the properties and color of the lunar surface.

The NAC works by building an image one line at a time. The first line is captured, then the orbit of the spacecraft moves the camera relative to the surface, and then the next line is captured, and so on, as thousands of lines are compiled into a full image.

According to Mark Robinson, professor and principal investigator of LROC at ASU’s School of Earth and Space Exploration, the jittery appearance of the image captured is the result of a sudden and extreme cross-track oscillation of the camera. LROC researchers concluded that there must have been a brief violent movement of the left Narrow Angle Camera.

There were no spacecraft events like solar panel movements or antenna tracking that might have caused spacecraft jitter during this period. “Even if there had been, the resulting jitter would have affected both cameras identically,” says Robinson. “The only logical explanation is that the NAC was hit by a meteoroid.”

Continue reading

New LRO Image



Image Credit: NASA/Goddard/Arizona State University

The original caption:
NASA’s Lunar Reconnaissance Orbiter (LRO) recently captured a unique view of Earth from the spacecraft’s vantage point in orbit around the moon.

“The image is simply stunning,” said Noah Petro, Deputy Project Scientist for LRO at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The image of the Earth evokes the famous ‘Blue Marble’ image taken by Astronaut Harrison Schmitt during Apollo 17, 43 years ago, which also showed Africa prominently in the picture.”

In this composite image we see Earth appear to rise over the lunar horizon from the viewpoint of the spacecraft, with the center of the Earth just off the coast of Liberia (at 4.04 degrees North, 12.44 degrees West). The large tan area in the upper right is the Sahara Desert, and just beyond is Saudi Arabia. The Atlantic and Pacific coasts of South America are visible to the left. On the moon, we get a glimpse of the crater Compton, which is located just beyond the eastern limb of the moon, on the lunar farside.

LRO was launched on June 18, 2009, and has collected a treasure trove of data with its seven powerful instruments, making an invaluable contribution to our knowledge about the moon. LRO experiences 12 earthrises every day; however the spacecraft is almost always busy imaging the lunar surface so only rarely does an opportunity arise such that its camera instrument can capture a view of Earth. Occasionally LRO points off into space to acquire observations of the extremely thin lunar atmosphere and perform instrument calibration measurements. During these movements sometimes Earth (and other planets) pass through the camera’s field of view and dramatic images such as the one shown here are acquired.

This image was composed from a series of images taken Oct. 12, when LRO was about 83 miles (134 kilometers) above the moon’s farside crater Compton. Capturing an image of the Earth and moon with LRO’s Lunar Reconnaissance Orbiter Camera (LROC) instrument is a complicated task. First the spacecraft must be rolled to the side (in this case 67 degrees), then the spacecraft slews with the direction of travel to maximize the width of the lunar horizon in LROC’s Narrow Angle Camera image. All this takes place while LRO is traveling faster than 3,580 miles per hour (over 1,600 meters per second) relative to the lunar surface below the spacecraft!

The high-resolution Narrow Angle Camera (NAC) on LRO takes black-and-white images, while the lower resolution Wide Angle Camera (WAC) takes color images, so you might wonder how we got a high-resolution picture of the Earth in color. Since the spacecraft, Earth, and moon are all in motion, we had to do some special processing to create an image that represents the view of the Earth and moon at one particular time. The final Earth image contains both WAC and NAC information. WAC provides the color, and the NAC provides high-resolution detail.

“From the Earth, the daily moonrise and moonset are always inspiring moments,” said Mark Robinson of Arizona State University in Tempe, principal investigator for LROC. “However, lunar astronauts will see something very different: viewed from the lunar surface, the Earth never rises or sets. Since the moon is tidally locked, Earth is always in the same spot above the horizon, varying only a small amount with the slight wobble of the moon. The Earth may not move across the ‘sky’, but the view is not static. Future astronauts will see the continents rotate in and out of view and the ever-changing pattern of clouds will always catch one’s eye, at least on the nearside. The Earth is never visible from the farside; imagine a sky with no Earth or moon – what will farside explorers think with no Earth overhead?”

NASA’s first Earthrise image was taken with the Lunar Orbiter 1 spacecraft in 1966. Perhaps NASA’s most iconic Earthrise photo was taken by the crew of the Apollo 8 mission as the spacecraft entered lunar orbit on Christmas Eve Dec. 24, 1968. That evening, the astronauts — Commander Frank Borman, Command Module Pilot Jim Lovell, and Lunar Module Pilot William Anders — held a live broadcast from lunar orbit, in which they showed pictures of the Earth and moon as seen from their spacecraft. Said Lovell, “The vast loneliness is awe-inspiring and it makes you realize just what you have back there on Earth.”



LADEE Impact Crater


The LADEE Impact crater on the far-side of the moon was found by the Lunar Reconnaissance Orbiter and the LRO camera called LROC.  Credit: NASA/GSFC/Arizona State University.

The LADEE spacecraft was launched from Wallops Island on 6 September 2013.  The spacecraft was sent to the moon to study the “surface bound exosphere and dust environment” or dust particles that might exist high above the surface to contribute to the Apollo-era debate about the existence – or not.

LADEE did not find any dust particles.  Mission completed LADEE fired its engines to enter a controlled descent that would cause it to impact the far-side of the moon even in the event the eclipse of 15 April 2014 caused the spacecraft to be otherwise uncontrollable.  The risk of not doing so would mean there would be no guarantee the impact would miss any Apollo landing sites.  Sure the odds probably would be slim but those sites are so historically significant that ANY chance is too much and a spacecraft with a mass of 248 kg / 547 pounds could cause damage.

The strategy was successful and LADEE  impacted the eastern rim of Sundman V crater (11.85°N, 266.75°E). The impact site (11.8494°N, 266.7507°E) is about 780 m from the crater rim with an altitude of about 2590 m, and was only about 295 meters north of its originally predicted location (based on tracking data).

There is an excellent LROC page devoted to this Impact image including before and after pictures – have a look.


Inside Tycho Crater


When we look up at the moon we can see the very large Tycho crater as above (image above wiki commons).

I’ve talked some about central peaks in recent posts and the Lunar Reconnaissance Orbiter has taken some spectacular images of Tycho at very close range. Click the image to see the central peak of Tycho from the LRO, that central peak is more than 2 km / 6562 ft high.

Not all craters have central peaks, it depends on the gravitational field of the body and the material being impacted and of course how large the impact is. Here is a very short video of the concept in a fluid. In rocky moons and planets the central peaks can be formed by the rock being pushed back up by the underlying substrate (rock) instead of the fluid in the video. It is very much like a rebound event.

There are lots of variables that play into the formation of central peaks. You can imagine if the impacted surface was say sandy regolith the peak would just fall down on itself and if the impacting body was not large enough material would be just swept away. Likewise an air burst meteor may not leave a central peak becuase the blast might not be concentrated enough. Even the angle of impact makes a difference.

So as you can see there is a lot to consider. Here is a great web page on crater forms from the University of Wisconsin – Green Bay.

The page where the above image of Tycho’s central peak came from gives a nice treatment of Shapes of Craters and there are even better shots of the central peak of Tycho from the LRO here.

Images: LRO / NASA

New Craters on the Moon

The bright flash of a meteor impact was seen on the moon a couple of years ago on 17 March 2013. The flash was some 10 times any flash recorded before. NASA recorded the flash at lunar coordinates 20.6°N, 336.1°E.

The Lunar Reconnaissance Orbiter was able to image the location before and after and it turns out it has found a few more.

The video and a really cool before/after image is located at the NASA site.`

Tycho’s Central Peaks

A beautful look at the central peaks of Tycho from the LRO. Image Credit: NASA/Goddard/Arizona State University
A beautful look at the central peaks of Tycho from the LRO. Click for a larger view. Image Credit: NASA/Goddard/Arizona State University

Todays moon post is from close to home, our own moon. The image above is the central peaks in the crater Tycho as seen by the Lunar Reconnaissance Orbiter. The central peak complex above is about 15 km / 9.3 miles wide, left to right (southeast to northwest in this view). A very popular target with amateur astronomers, Tycho is about 82 km / 51 miles in diameter. The central peak’s summit is 2 km / 1.24 miles above the crater floor.

You have seen Tycho if you ever looked up that the full moon on a clear sky. A pair of binoculars will show the central peak. Here’s a look at Tycho  from the Simon Fraser University.

Central craters generally form from an impact of a large body onto in this case the lunar surface. The heat generates surface melt and the “liquid” is pushed from the point of impact and then rebounds from the edges back to the center and freezes in place. Rock freezes at a much higher temperature than water as you well know.

Impact craters are a whole study on their own and there are many different types. The University of Wisconsin at Green Bay has a nice web page looking at the different types of craters and central peak formation. Depending on what body the craters are on they may appear a little different than lunar craters, for example: craters on Mercury generally are a little more muted the walls and central peaks don’t seem to reach out as much as lunar craters, this is because in part, Mercury has more gravity than the moon.

Click here to visit the source page for the image and more information about Tycho.