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Cassini Bids Farewell to Dione with Some Fantastic Final Views

Mosaic of Saturn's 700-mile-wide moon Dione made from nine images acquired on Aug. 17, 2015. Saturn itself covers the entire background. (NASA/JPL/SSI)

Mosaic of Saturn’s 700-mile-wide moon Dione made from nine images acquired during its “D-5” flyby on Aug. 17, 2015. Saturn itself covers the entire background. (NASA/JPL/SSI)

NASA’s venerable Cassini spacecraft may still have another two years left in its exploration of the Saturn system but on Monday, August 17, it had its final intimate visit with Dione, one of Saturn’s largest natural satellites at nearly 700 miles (1,126 km) across. On that day Cassini passed within 300 miles (480 km) of Dione at 2:33 p.m. EDT (18:33 UTC), not its closest flyby ever but certainly near enough to get some truly spectacular views of the icy moon’s ancient and cratered surface.

Check out some of Cassini’s last close-up images of Dione below:

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Today in 1966: Lunar Orbiter I Launched to Map our Moon

Earth was seen from the Moon for the first time by Lunar Orbiter I on August 23, 1966. (NASA/LPI/USGS)

Earth was seen from the Moon for the first time by Lunar Orbiter I on August 23, 1966. (NASA/LPI/USGS)

A test version of a Lunar Orbiter spacecraft. (Eric Long, National Air & Space Museum)

A test version of the 2-meter-long, 390-kg Lunar Orbiter spacecraft. (Eric Long, National Air & Space Museum)

On August 10, 1966, NASA’s Lunar Orbiter I launched from Cape Canaveral aboard an Atlas-Agena D rocket, the flagship spacecraft of a program designed to map the Moon and investigate intended landing sites for the planned Apollo landings, including helping determine the risks from micrometeorite and radiation exposure. Over the course of the next twelve months and five successful missions the Lunar Orbiter program photographed 99% of the Moon’s surface, both nearside and far, to a resolution as fine as 1 meter – which at the time was ten times better than what could be achieved from Earth.

Lunar Orbiter I was also responsible for sending back our first views of Earth from lunar orbit, one of which can be seen above.

Learn more about Lunar Orbiter here, and see original images from the Lunar Orbiter program here. Also, check out a cool old Apollo-era film about the Lunar Orbiter and Apollo prep missions below:

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Mars Will NOT Be As Big As The Moon In The Night Sky

There will not be

There will not be “two Moons” in the sky on August 27, 2015, despite what this circulating image claims. (Original credit unknown.)

No, no, no…a thousand times NO: Mars will not become a “second Moon” in the sky on August 27. It won’t this year, it didn’t last year, and it didn’t in the past dozen years since this silly yet strangely perennial cyber-legend (yes I just used the prefix “cyber”) first started circulating on teh interwebz. I don’t know why it keeps rising from the e-dead every year, some years more omnipresently than others, but the bottom line is it simply won’t happen. Not this time, not ever… the Solar System just doesn’t work that way. (And good thing too!)

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The Hammer-Feather Drop: Watch Apollo 15 Commander Dave Scott “Do a Science” on the Moon

On August 2, 1971, at the end of the last EVA of the Apollo 15 mission, Commander David Scott took a few minutes to conduct a classical science experiment in front of the TV camera that had been set up just outside the LM Falcon at the Hadley Rille landing site. Scott, a former Air Force pilot, recreated a famous demonstration often attributed to Galileo (which may or may not have actually been performed by the astronomer in Pisa in 1586) that shows how objects of different masses react the same way to gravity when dropped – that is, they fall at the same rate.

By performing the “acceleration test” in the vacuum environment of space (but where there is still an observable downward pull of gravity) the element of air resistance is negated – especially on such a low-mass and low-density object as a falcon feather – thereby creating a more “pristine” setting for the centuries-old experiment than could ever be achieved on Earth.

According to a report on the mission’s science objectives: “During the final minutes of the third extravehicular activity, a short demonstration experiment was conducted. A heavy object (a 1.32-kg aluminum geological hammer) and a light object (a 0.03-kg falcon feather) were released simultaneously from approximately the same height (approximately 1.6 m) and were allowed to fall to the surface. Within the accuracy of the simultaneous release, the objects were observed to undergo the same acceleration and strike the lunar surface simultaneously, which was a result predicted by well-established theory, but a result nonetheless reassuring considering both the number of viewers that witnessed the experiment and the fact that the homeward journey was based critically on the validity of the particular theory being tested. ” (Joe Allen, NASA SP-289, Apollo 15 Preliminary Science Report, Summary of Scientific Results, p. 2-11. Source.)

Launched on July 26, 1971, Apollo 15 was the first of the “J” missions capable of a longer stay time on the moon and greater surface mobility, thanks to the use of the Lunar Roving Vehicle (LRV).Learn more about the Apollo 15 mission here.

This is Our Best Photo of Neil Armstrong on the Moon

Panorama from Apollo 11 showing Neil Armstrong at the LM Eagle (NASA)

Panorama from Apollo 11 showing Neil Armstrong at the LM Eagle, with the US flag and Solar Wind Experiment at left. (NASA)

Everyone knows that Apollo 11 commander Neil A. Armstrong was the first human to set foot on the Moon (and if you didn’t know, that occurred on July 20, 1969 – yes, it really happened). It was a momentous, history-making event that many (like myself) consider one of the most impressive achievements of humankind. But oddly enough, even with high-resolution Hasselblad film cameras there on location, there are very few photos showing Armstrong himself on the surface of the Moon. In fact the one above, a panorama captured by fellow Apollo 11 astronaut Buzz Aldrin, really is the best image in existence of Neil on the Moon.

So…why is that?

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Pluto’s Ice Mountains Revealed in Stunning Detail

Enormous ice mountains discovered on Pluto

Enormous ice mountains discovered on Pluto. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

At 3 p.m. EDT today, July 15 2015, from the Johns Hopkins University’s Applied Physics Laboratory in Laurel, Maryland, the New Horizons team revealed to the world the first high-resolution image acquired of the surface of Pluto. This was obtained during the historic July 14 flyby with New Horizons’ “Ralph” camera, and it’s our very first close-up view of this distant world’s fascinating, beautiful, and surprisingly crater-free surface! Of course more will be coming as the days, weeks, and months pass, and many further studies will be done to determine the nature of all of the features revealed, but for now – enjoy.

This is truly an amazing time in space exploration!

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