For years, scientists have been hunting for the stable lava tubes that are believed to exist on the Moon. A remnant from the Moon’s past, when it was still volcanically active, these underground channels could very well be an ideal location for lunar colonies someday. Not only would their thick roofs provide naturally shielding from solar radiation, meteoric impacts, and extremes in temperature. They could also be pressurized to create a breathable environment.
But until now, evidence of their existence has been inferred from surface features such as sinuous rilles – channel-like depressions that run along the surface that indicate the presence of subterranean lava flows – and holes in the surface (aka. “skylights”). However, recent evidence presented at the 47th Lunar and Planetary Science Conference (LPSC) in Texas indicates that one such stable lava tube could exist in the once-active region known as Marius Hills.
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.
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.
NASA’s planetary senior review panel harshly criticized the scientific return of the Curiosity rover in a report released yesterday (Sept. 3), saying the mission lacks focus and the team is taking actions that show they think the $2.5-billion mission is “too big to fail.”
While the review did recommend the mission receive more funding — along with the other six NASA extended planetary missions being scrutinized — members recommended making several changes to the mission. One of them would be reducing the distance that Curiosity drives in favor of doing more detailed investigations when it stops.
The role of the senior review, which is held every two years, is to help NASA decide what money should be allocated to its extended missions. This is important, because the agency (as with many other departments) has limited funds and tries to seek a balance between spending money on new missions and keeping older ones going strong.
Engineering acumen means that many missions are now operating well past their expiry dates, such as the Cassini orbiter at Saturn and the Opportunity rover on Mars. In examining the seven missions being reviewed, the panel did recommend keeping funding for all, but said that 4/7 are facing significant problems.
In the case of Curiosity, the panel called out principal investigator John Grotzinger for not showing up in person on two occasions, preferring instead to interact by phone. The review also said there is a “lack of science” in its extended mission proposal with regard to “scientific questions to be answered, testable hypotheses, and proposed measurements and assessment of uncertainties and limitations.”
Other concerns were the small number of samples over the prime and extended missions (13, a “poor science return”), and a lack of clarity on how the ChemCam and Mastcam instruments will play into the extended mission. Additionally, the panel expressed concern that NASA would cut short its observations of clays (which could help answer questions of habitability) in favor of heading to Mount Sharp, the mission’s ultimate science destination.
“In summary, the Curiosity … proposal lacked scientific focus and detail,” the panel concluded, adding in its general recommendations for the reviews that principal investigators must be present to avoid confusion while answering questions. The other missions facing concern from the panel included the Lunar Reconnaissance Orbiter, Mars Express and Mars Odyssey.
LRO: Its extended mission (the second) is supposed to look at how the moon’s surface, subsurface and exosphere changes through processes such as meteorites and interaction with space. The panel was concerned with a “lack of detail” in the proposal and in answers to follow-up questions. The panel also recommended turning off certain instruments “at the end of their useful science mission”.
Mars Express: The extended mission is focusing on the ionosphere and atmosphere as well as the planet’s surface and subsurface. Concerns were raised about matters such as why funding is needed to calibrate its high-resolution stereo camera after 11 years — especially given the instrument has been rarely cited in published journal reports lately — and how people involved in the extended mission would meet the goals. The panel also saw a “lack of communication” in the team.
Mars Odyssey: If approved, the spacecraft will move to the day/night line of Mars to look at the planet’s radiation, gamma rays, distribution of water/carbon dioxide/dust in the atmosphere, and the planet’s surface. The panel, however, said there are no “convincing arguments” as to how the new science relates to the Decadal Survey objectives for planetary science. Odyssey, which is in its 11th year, may also be nearing the end of its productive lifespan given fewer publications using its data in recent years, the panel said.
The panel also weighed in on the success of the Cassini and Opportunity missions:
Cassini received the highest rating — “Excellent” — due to its scientific merit, the only mission this time around to do so. The panel was particularly excited about seasonal changes that will be seen on Titan in the coming years, as well as measurements of Saturn’s rings and magnetosphere and its icier moons (such as Enceladus). The spacecraft is noted to be in good condition and the new mission will be a success because of “the unique aspect of the new observations.”
Opportunity, which is more than 10 years into its Mars exploration, is still “in sufficiently good condition” to do science, although the panel raised concerns about software and communication problems. The panel, however, said more time with the rover would allow it to look for evidence of past water on Mars that would not be visible from orbit — even though it’s unclear if phyllosilicates around its current location (Endeavour crater) are from the Noachian period, the earliest period in Mars’ history.
The panel is just one step along the road to figuring out how NASA chooses to spend its money in the coming years. Funding availability depends on how much money Congress allocates to the agency.
Forty-five years ago yesterday, the Sea of Tranquility saw a brief flurry of activity when Neil Armstrong and Buzz Aldrin dared to disturb the ancient lunar dust. Now the site has lain quiet, untouched, for almost half a century. Are any traces of the astronauts still visible?
The answer is yes! Look at the picture above of the site taken in 2012, two years ago. Because erosion is a very gradual process on the moon — it generally takes millions of years for meteors and the sun’s activity to weather features away — the footprints of the Apollo 11 crew have a semi-immortality. That’s also true of the other five crews that made it to the moon’s surface.
In honor of the big anniversary, here are a few of NASA’s Lunar Reconnaissance Orbiter’s pictures of the landing sites of Apollo 11, Apollo 12, Apollo 14, Apollo 15, Apollo 16 and Apollo 17. (Apollo 13 was slated to land on the moon, but that was called off after an explosion in its service module.)
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.
While people across North America marvelled at the blood-red moon early this morning, some NASA engineers had a different topic on their minds: making sure the Lunar Reconnaissance Orbiter would survive the period of extended shadow during the eclipse.
LRO uses solar panels to get energy for its batteries, so for two passes through the Earth’s shadow it would not be able to get any sunlight at all. Tweets on the official account show all as well in the first few hours after the eclipse.
“The spacecraft will be going straight from the moon’s shadow to the Earth’s shadow while it orbits during the eclipse,” stated Noah Petro, LRO’s deputy project scientist at NASA’s Goddard Space Flight Center, in a release before the eclipse occurred.
“We’re taking precautions to make sure everything is fine,” Petro added. “We’re turning off the instruments and will monitor the spacecraft every few hours when it’s visible from Earth.”
LRO’s Twitter account asked “Who turned off the heat and lights?” during the eclipse, then reported a happy acquisition of signal after the shadow passed by. “AOS, and sunlight, sweet sunlight! My batteries are charging again before I make another trip to the lunar far side.”
The Earth has a single moon, while Saturn has more than 60, with new moons being discovered all the time. But here’s a question, can a moon have a moon? Can that moon’s moon have its own moon? Can it be moons all the way down?
First, consider that we have a completely subjective idea of what a moon is. The Moon orbits the Earth, and the Earth orbits the Sun, and the Sun orbits the center of the Milky Way, which orbits within the Local Group, which is a part of the Virgo Supercluster. The motions of objects in the cosmos act like a set of Russian nesting dolls, with things orbiting things, which orbit other things. So maybe a better question is: could any of the moons in the Solar System have moons of their own? Well actually, one does.
Right now, NASA’s Lunar Reconnaissance Orbiter is happily orbiting around the Moon, photographing the place in high resolution. But humans sent it to the Moon, and just like all the artificial satellites sent there in the past, it’s doomed. No satellite we’ve sent to the Moon has ever orbited for longer than a few years before crashing down into the lunar surface. In theory, you could probably get a satellite to last a few hundred years around the Moon.
But why? How come we can’t make moons for our moon to have a moon of it’s own for all time? It all comes down to gravity and tidal forces. Every object in the Universe is surrounded by an invisible sphere of gravity. Anything within this volume, which astronomers call the “Hill Sphere”, will tend to orbit the object.
So, if you had the Moon out in the middle of space, without any interactions, it could easily have multiple moons orbiting around it. But you get problems when you have these overlapping spheres of influence. The strength of gravity from the Earth tangles with the force of gravity from the Moon.
Although a spacecraft can orbit the Moon for a while, it’s just not stable. The tidal forces will cause the spacecraft’s orbit to decay until it crashes. But further out in the Solar System, there are tiny asteroids with even tinier moons. This is possible because they’re so far away from the Sun. Bring these asteroids closer to the Sun, and someone’s losing a moon.
The object with the largest Hill Sphere in the Solar System is Neptune. Because it’s so far away from the Sun, and it’s so massive, it can truly influence its environment. You could imagine a massive moon distantly orbiting Neptune, and around that moon, there could be a moon of its own. But this doesn’t appear to be the case.
NASA is considering a mission to capture an asteroid and put it into orbit around the Moon. This would be safer than having it orbit the Earth, but still keep it close enough to extract resources. But without any kind of orbital boost, those tidal forces will eventually crash it onto the Moon. So no, in our Solar System, we don’t know of any moons with moons of their own. In fact, we don’t even have a name for them. What would you suggest?
Scientists from the Lunar Reconnaissance Orbiter say that Icarus Crater is one of a kind on the Moon because its central peak rises higher than about half its rim. Most central peaks rise only about halfway to the crater rim. But at just the ring angle and lighting conditions, the shadow this central peak creates on the rolling and jagged crater rim looks like the Star Wars Character Yoda. Interestingly, this crater is located on what some people erroneously call the “Dark Side” of the Moon – what is actually the lunar farside.
Below you can see a closeup of the central peak of Icarus crater rising out of the shadows to greet a new lunar day.
Icarus is located just west of Korolev crater on the lunar farside. The light-colored plains surrounding the craters were deposited during the formation of the Orientale basin, which is located over 1500 km away.
Find out more about these images from LRO and see larger versions at the LROC website.