Posts: 5245 From: Sierra Vista, Arizona Registered: Nov 1999
posted 03-15-2012 11:54 AM
Derived from LRO data...
Two New NASA LRO Videos: See Moon's Evolution, Take a Tour
In honor of 1,000 days in orbit, the NASA Lunar Reconnaissance Orbiter team at NASA Goddard Space Flight Center in Greenbelt Md. has released two new videos.
One video takes viewers through the moon's evolutionary history, and reveals how it came to appear the way it does today. Another video gives viewers a guided tour of prominent locations on the moon's surface, compiled by the spacecraft's observations of the moon.
"Evolution of the Moon" explains why the moon did not always look like it does now. The moon likely started as a giant ball of magma formed from the remains of a collision by a Mars sized object with the Earth about four and a half billion years ago. After the magma cooled, the moon's crust formed.
Then between 4.5 and 4.3 billion years ago, a giant object hit near the moon's South Pole, forming the South Pole-Aitken Basin, one of the two largest proven impact basins in the solar system. This marked the beginning of collisions that would cause large scale changes to the moon's surface, such as the formation of large basins.
Because the moon had not entirely cooled on the inside, magma began to seep through cracks caused by impacts. Around one billion years ago, it's thought that volcanic activity ended on the near side of the moon as the last of the large impacts made their mark on the surface.
The moon continued to be battered by smaller impacts. Some of the best-known impacts from this period include the Tycho, Copernicus, and Aristarchus craters.
So, while the moon today may seem to be an unchanging world, its appearance is the result of billions of years of violent activity.
"Tour of the Moon" takes viewers to several interesting locations on the moon.
Tour stops included in this breathtaking journey across the moon's surface are: Orientale Basin, Shackleton crater, South Pole-Aitken Basin, Tycho crater, Aristarchus Plateau, Mare Serenitatis, Compton-Belkovich volcano, Jackson crater and Tsiolkovsky crater.
MCroft04 Member
Posts: 1811 From: Smithfield, Me, USA Registered: Mar 2005
posted 03-16-2012 08:26 PM
I'm surprised that reputable scientists are not acknowledging that the impact theory is being challenged by recent work on the volcanic glasses brought back by Apollo astronauts.
New analytical techniques are detecting significant amounts of water associated with these glasses. Water is a volatile, and it is unlikely that it would have survived the heat of a giant impact.
As Jack Schmitt acknowledged at the Apollo 15 40th anniversary celebration, "I think we're going to have to rethink this one."
SpaceAholic Member
Posts: 5245 From: Sierra Vista, Arizona Registered: Nov 1999
posted 10-12-2016 09:56 PM
quote:Originally posted by Paul Littler: So is there any news of new craters formed since the 1970s?
New craters are forming on the surface of the moon more frequently than scientists had predicted, a new study has found, reports Space.com.
The researchers discovered 222 craters on the moon that appeared on the surface after the first LRO images were taken — that is 33 percent more than predicted by current models. These were at least 32 feet (10 meters) across, and ranged up to about 140 feet (43 m) wide.
The scientists also found broad zones around these new craters that they interpreted as the remains of jets of debris following impacts. They estimated this secondary cratering process is churning the top 0.8 inches (2 centimeters) of lunar dirt, or regolith, across the entire lunar surface more than 100 times faster than thought.
"I'm excited by the fact that we can see the regolith evolve and churn — a process that was believed to take hundreds of thousands to millions of years to occur — in images acquired over the past several years," Speyerer told Space.com.
Blackarrow Member
Posts: 3602 From: Belfast, United Kingdom Registered: Feb 2002
posted 10-15-2016 12:26 PM
This seems to mean that the footprints of the Apollo astronauts might only last 5,000 to 10,000 years. Obviously this assumes no "direct hits," but even a "direct hit" would only affect one site, or (more likely) a small part of one site.
oly Member
Posts: 1450 From: Perth, Western Australia Registered: Apr 2015
posted 04-18-2018 08:54 PM
Here is a Goddard Space Flight Centre 4K LRO tour of the Moon. I thought some may find interesting. I particularly found the Apollo 17 landing site imagery fascinating.
HelmetHair Member
Posts: 105 From: London, England. Registered: Feb 2007
posted 06-15-2018 05:09 PM
Gene Cernan stamped out his daughters initials in the regolith. I don't know how big they were, or where they were in relation to the lunar module.
Would they be visible in the Apollo 17 LRO pics?
HelmetHair Member
Posts: 105 From: London, England. Registered: Feb 2007
posted 06-16-2018 02:56 AM
Question answered, yes you can find the flag - but what does it look like? Have the stars and stripes faded? That question will remain for a future landed spacecraft.
My thoughts about whether the flags still exist is that they do, but will be extraordinarily fragile. Much the way a newspaper page can be cooked in an oven and still readable, but if you touch it it begins to crumble.
On a flagpole and supported along the top, the flags may still be in one piece and casting a shadow, and the lower gravity means their own weights aren't making them fall apart, and the lack of atmospheric disturbance means they aren't being "shaken apart."
Essentially they are intact and casting a shadow, but unable to be touched without being destroyed.
As to the bleaching effect, it sounds reasonable that the flags would be pale to the point of almost being colourless, but they would still be an obstacle to sun and cast a shadow.
Robert Pearlman Editor
Posts: 50476 From: Houston, TX Registered: Nov 1999
posted 06-16-2018 07:40 AM
quote:Originally posted by HelmetHair: Would they be visible in the Apollo 17 LRO pics?
LRO's narrow angle cameras resolve surface features down to half a meter (1.6 feet) per pixel, so no, the initials would be too small to image.
(Cernan drew his daughter's initials in the regolith near where he parked the lunar rover for the last time. In 2016, Cernan met with PTScientists, the Audi-backed company working to send their first robotic rover to the Apollo 17 landing site [and specifically the LRV parking site], and requested they image the initials when there.)
Rick Mulheirn Member
Posts: 4522 From: England Registered: Feb 2001
posted 02-12-2021 02:59 PM
I must confess to unfathomable ignorance when it comes to the LRO mission. But I was wondering, what are the chances the spacecraft's orbit could be lowered as the mission nears a conclusion in order to obtain even better high resolution images of the Apollo landing sites?
Blackarrow Member
Posts: 3602 From: Belfast, United Kingdom Registered: Feb 2002
posted 05-23-2023 06:02 PM
LRO is still (as far as I know) going strong after 14 years. I can't find any NASA information about LRO's expected lifespan, but if there is no known issue that will bring the mission "prematurely" to an end, I assume the key life-limiting factors will be on-board fuel and loss of power during eclipses.
Does anyone know how long the fuel will last? I don't know if LRO orientates with internal gyros or thrusters, but at some point if it runs out of fuel to raise a reducing orbit, it will hit the Moon. How much longer is LRO likely to survive?
Headshot Member
Posts: 1220 From: Vancouver, WA, USA Registered: Feb 2012
posted 05-23-2023 08:50 PM
Good question. I, also, am interested to know. I know for certain that it survived at least one hit by a small meteroid that was strong enough to blur the image it was taking at the time.
Also, does NASA have some sort of replacement for LRO planned?
Jim Behling Member
Posts: 1815 From: Cape Canaveral, FL Registered: Mar 2010
posted 05-23-2023 09:27 PM
No. It did without one for more than 30 years before LRO.
Robert Pearlman Editor
Posts: 50476 From: Houston, TX Registered: Nov 1999
posted 05-23-2023 10:24 PM
According to Noah Petro, project scientist for LRO at Goddard Space Flight Center, in an 2021 interview, fuel may be the spacecraft's limiting factor. He estimated then that they had "at least five more years of fuel on board, if not more."
LRO lost use of its Miniature Inertial Measurement Unit (MIMU) in 2018, such that it has to rely solely on star trackers to orient itself. In 2020, it received a software upgrade to regain its ability for "fast maneuvering."
Though Jim is correct and there is no currently budgeted replacement for LRO, if the need exists, it is not hard to imagine a similar capability being built into a communications relay satellite or other orbiter as Artemis progresses and more international and commercial missions are planned.
oly Member
Posts: 1450 From: Perth, Western Australia Registered: Apr 2015
posted 05-24-2023 03:59 AM
It would not surprise me if a constellation of GPS lunar satellites was something someone planned to create soon. This would be beneficial for lunar surface exploration as well as spacecraft navigation and precision landing.
Jim Behling Member
Posts: 1815 From: Cape Canaveral, FL Registered: Mar 2010
posted 05-24-2023 09:24 AM
Not this decade.
davidcwagner Member
Posts: 989 From: Albuquerque, New Mexico Registered: Jan 2003
posted 05-24-2023 07:04 PM
The Goddard Space Flight Centre 4K LRO video is the best because it has both a scale and long/lat data for the center of the view. Videos without scales are B grade at best.