An artist's illustration of NASA's OSIRIS-REx spacecraft approaching asteroid Bennu with its sampling instrument extended. Image Credit: NASA/Goddard/University of Arizona
NASA has granted mission extensions to eight different planetary missions, citing the continued excellent operations of the spacecraft, but more importantly, the sustained scientific productivity of these missions, “and the potential to deepen our knowledge and understanding of the solar system and beyond.” Each mission will be extended for three more years.
One of the most exciting extensions gives a new mission to the OSIRIS-REx spacecraft, sending it to one of the most infamous asteroids of them all, the potentially hazardous asteroid Apophis.
On Tuesday, December 1st, at 10:11 EST (07:00 PST) the Chang’e-5 sample return spacecraft landed safely on the Moon. This mission is the latest in China’s lunar exploration program, which is paving the way for the creation of a lunar outpost and a crewed mission by the 2030s. The day after it landed, the Lunar Reconnaissance Orbiter (LRO) passed over the site and acquired an image of the lander.
Ryder Crater on the Moon. Credit: NASA/GSFC/Arizona State University.
This may be one of the strangest craters you’ll ever see.
Ryder crater is located near the south pole of our Moon, and it has a bizarre oblong shape (approximately 13 x 17 km in size), with a ridge cutting across the middle.
The majority of impact craters are round. How did Ryder crater end up in this odd shape?
In 2009, NASA launched the Lunar Reconnaissance Orbiter (LRO), the first mission to be sent by the US to the Moon in over a decade. Once there, the LRO conducted observations that led to some profound discoveries. For instance, in a series of permanently-shaded craters around the Moon’s South Pole-Aitken Basin, the probe confirmed the existence of abundant water ice.
The new crater is located on a steep slope, greater than 20°, measured from an LROC NAC Digital Terrain Model. Credit: NASA/GSFC/Arizona State University
On May 20th, 2018, the China National Space Agency (CNSA) launched the Queqiao spacecraft, the vehicle that would deliver the Chang’e-4mission to the Moon. This vehicle was also responsible for transporting a lesser-known mission to the Moon, known as the Longjiang twin spacecraft. This package consisted of two satellites designed to fly in formation and validate technologies for low-frequency radio astronomy.
While Queqiao flew beyond the Moon to act as a communications relay for the Chang’e-4 lander, the Longjiang satellites were to enter orbit around the moon. On July 31st, 2019, after more than a year in operation, the Longjiang-2 satellite deorbited crashed on the lunar surface. And thanks to efforts spacecraft tracker Daniel Estévez and his colleagues, the Lunar Reconnaissance Orbiter (LRO) was able to photograph the impact site.
The Chandrayaan-2 lander, Vikram, attempted a landing September 7th (Friday the 6th in the United States), on a small patch of lunar highland smooth plains between Simpelius N and Manzinus C craters. Unfortunately the landing was not successful and location of the spacecraft has not been announced. The scene above was captured from an LROC Quickmap fly-around of the site, image width is about 150 kilometers across the center [NASA/GSFC/Arizona State University].
This image of the lunar highlands is from NASA’s Lunar Reconnaissance Orbiter. You’d need superhuman eyesight to spot it, but India’s crashed Vikram lander is in there somewhere. The lander attempted to land on the Moon on September 6th, but when it was only 2.1 km above the surface, within reach of its objective, ISRO (Indian Space Research Organization) lost contact with the spacecraft.
Conceptual illustration of permanently shadowed, shallow icy craters near the lunar south pole. Credits: UCLA/NASA
In addition to being the only solvent that is capable of supporting life, water is essential to life as we know it here on Earth. Because of this, finding deposits of water – whether in liquid form or as ice – on other planets is always exciting. Even where is not seen as a potential indication of life, the presence of water offers opportunities for exploration, scientific study, and even the creation of human outposts.
This has certainly been the case as far as the Moon and Mercury are concerned, where water ice was discovered in the permanently-shadowed cratered regions around the poles. But according to a new analysis of the data from the Lunar Reconnaissance Orbiter and the MESSENGER spacecraft, the Moon and Mercury may have significantly more water ice than previously thought.
The history of the Moon is a tale told by geology, apparent in its rocks, craters, and other surface features. For centuries, astronomers have studied the Moon from afar and for the past few decades, it has been visited by countless robotic missions. Between 1969 and 1972, a total of twelve astronauts walked on its surface, conducted lunar science, and brought samples of lunar rock back to Earth for study.
These efforts have taught us a lot about the things that have shaped the lunar surface, be they one-off events like the massive impact that formed the Shakleton crater to things that happened regularly throughout its 4.51 billion-year history. For instance, scientists recently discovered something unusual about the Antoniadi crater: a large boulder was perched on the rim of a smaller crater within after rolling about 1000 meters (1093 yards) downhill.
NASA's Visualization Studio has released its yearly moon simulation viewer. Image: NASA
It’s always easier to show someone a picture of something rather than to use 1,000 words to explain it. The people at NASA’s Scientific Visualization Studio (SVS) know this, and they’re experts. Every year they release a simulation of the Moon that shows what the Moon will look like to us each day.
NASA’s Moon simulator uses images and data captured by the Lunar Reconnaissance Orbiter (LRO) to recreate the Moon on each hour of each day of each month in 2018. You can input any date and time to view the Moon (Dial-a-Moon) as it will appear at that time. You can also watch a video of the Moon over the course of the entire year. Along the way, you might learn something.
A brand new crater on the Moon! This new 12 meter (39 foot) diameter impact crater formed between 25 October 2012 and 21 April 2013 Credit: NASA/GSFC/Arizona State University].
Animation of a temporal pair of the new 39-foot (12-meter) impact crater on the moon photographed by NASA’s Lunar Reconnaissance Orbiter Credit: NASA/GSFC/Arizona State University
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.
One of a series of photos Apollo 11 astronaut Edwin Aldrin made of his bootprint in the dusty, sandy lunar soil, called regolith. Based on a newy study, the impression may disappear in a few tens of thousands of years instead a few million. Credit: NASA
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.
This map shows the distribution of new impact craters (yellow dots) discovered by analyzing 14,000 narrow-angle camera (NAC) temporal pairs. The two red dots mark the location of the March 17, 2013 and September 11, 2013 impacts that were recorded by Earth-based video monitoring. LRO’s mission was recently extended an addition two years through September 2018. Credit: NASA/GSFC/ASUThe 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.
LRO before and after images of an impact event on March 17, 2013. The newly formed crater is 59 feet (18 meters) in diameter. Subsurface regolith not exposed to sunlight forms a bright halo around the new crater. There also appears to be a larger nimbus of darker reflectance material visible much further beyond but centered on the impact. Credit: NASA/GSFC/Arizona State University
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.
An artist’s illustration of a meteoroid impact on the Moon. Impacts dig up fresh material from below as well as send waves of hot rock vapor and molten rock across the lunar landscape, causing a much faster turnover of the moon soil than previously thought. Credit: NASA
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.
Here are two examples of a low reflectance (top) and high reflectance (bottom) splotch created either by a small impactor or more likely from secondary ejecta. In either case, the top few inches of the regolith (soil) was churned Credit: NASA/GSFC/Arizona State UniversityBased 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!
![Distribution of new impact craters (yellow dots) discovered by analyzing 14,000 NAC temporal pairs. The two red dots mark the location of the 17 March 2013 and the 11 September 2013 impacts that were recorded by Earth-based video monitoring [NASA/GSFC/Arizona State University]](https://www.universetoday.com/wp-content/uploads/2016/10/Moon-new-crater-distribution-NASA-GSFC-ASU.jpg)
![Example of a low reflectance (top) and high reflectance (bottom) splotch created either by a small impactor or more likely from secondary ejecta. In either case, the top few centimeters of the regolith (soil) was churned [NASA/GSFC/Arizona State University].](https://www.universetoday.com/wp-content/uploads/2016/10/Moon-craters-splotches-NASA.gif)