supra lunam pura omnia ac diurnae lucis plena

I don't exclusively get ramped up by American space exploration, of course, so here's a fun anniversary:

Lunokhod 1 was the first successful rover to explore another world. It arrived on the moon on Nov. 17, 1970, upon the Luna 17 lander. Driven by remote-control operators in the Soviet Union, it travelled more than 10 kilometers (6 miles) in just 10 months. By comparison, it took the Mars Opportunity rover about six years to reach the same milestone... 

The Soviet Union had pinned its hopes of a manned moon landing on the Zond rocket. However, following a series of test failures, including a deadly launch pad explosion in 1968, the Soviet Union focused on other moon programs instead. Among them was robotically landing a probe on the moon, and operating a rover remotely... 

Luna 17 launched successfully on Nov. 10, 1970, and made it to lunar orbit five days later. It soft-landed in the Sea of Rains, and Lunokhod 1, the rover it carried onboard, descended a ramp to the lunar surface.

"Lunokhod 1 was a lunar vehicle formed of a tub-like compartment with a large convex lid on eight independently powered wheels," NASA wrote in a summary of the mission. "Lunokhod was equipped with a cone-shaped antenna, a highly directional helical antenna, four television cameras, and special extendable devices to impact the lunar soil for soil density and mechanical property tests."

The rover was solar-powered by day and relied on thermal energy from a polonium-210 radioisotope heater to survive the nighttime cold, when temperatures reached minus 150 degrees Celsius (minus 238 Fahrenheit). Because the moon always has one side facing the Earth, this means that daylight on most spots on the surface lasts about two weeks. Night is also two weeks long. The rover was designed to last three lunar days. It exceeded its operational projection, lasting for eleven lunar days; operations ceased on Oct. 4, 1971, which was exactly 14 years after the Soviet Union's first satellite, Sputnik, reached Earth orbit.

Now fast forward to 2010:

A Soviet robot lost on the dusty plains of the Moon for the past 40 years has been found again, and it is returning surprisingly strong laser pulses to Earth.

"We shined a laser on Lunokhod 1's position, and we were stunned by the power of the reflection," says Tom Murphy of UC San Diego, who leads the research team that's putting the old robot back to work. "Lunokhod 1 is talking to us loudly and clearly."...

Lunokhod-1 was lost – until last month when NASA's Lunar Reconnaissance Orbiter found it again. The recovery is described in an earlier NASA press release.

On April 22, Murphy and his team sent pulses of laser light from the 3.5 meter telescope at the Apache Point Observatory in New Mexico, zeroing in on the target coordinates provided by Lunar Reconnaissance Orbiter. A laser retroreflector on Lunokhod 1 intercepted the pulses and sent a clear signal back to Earth.

"We got about 2,000 photons from Lunokhod 1 on our first try. After almost 40 years of silence, this rover a lot to say," notes Murphy.

Back in the late 1960s and early 1970s, Apollo astronauts placed three other retroflectors on the Moon to allow laser ranging of the Moon's orbit. Assisted by a fourth reflector on Lunokhod 2, a twin of Lunokhod 1 that landed in 1973, these mirrors constitute the only Apollo science experiment still operating... 

Murphy's initial reaction was disbelief: "The signal was so strong, my first thought was that our detector was acting up! I expected the rover's reflector to be degraded and dull after all this time, so I thought, 'this couldn't possibly be it.' But it was."

"This reflector is even strong enough to let us get measurements in lunar daylight – a first for this experiment!"

Silverberg continues: "The fact that Lunokhod 1's reflection is now stronger than that of its twin is a mystery. This may yield important clues as to why all of the reflectors are weaker than in the first decade after landing."

With Lunokhod 1 back in the fold, the laser ranging study can get up to full throttle for the first time.

The scientists are using laser ranging to push hard on Einstein's gravity theory "to see if we can break it," says Murphy.

Wunderbar!  Speaking of lunar rovers and American exploration:

Preparations continued for the July 1971 Apollo 15 mission, the first with expanded capabilities including a longer lunar surface stay time of three days and the use of the Lunar Roving Vehicle (LRV) to expand the range of astronauts’ geology excursions. The Grumman Aircraft Corporation delivered the two stages of the Lunar Module (LM) to KSC, with the ascent stage arriving on Nov. 6 and the descent stage 10 days later.  Workers in the MSOB began LM systems tests on Nov. 30. The Boeing Co. delivered the LRV 1-G trainer to the Marshall Space Flight Center on Nov. 17 for initial testing, following which it was delivered to the Manned Spacecraft Center, now NASA’s Johnson Space Center in Houston, on Dec. 16 for astronaut training... 

During a two-day geology field trip Nov. 19-20 to the San Gabriel Mountains in California, Scott, Irwin, Gordon, and Schmitt used cameras and sample collection equipment to practice collecting and photo documenting samples. A lengthier field trip to the islands of Hawaii and Oahu Dec. 5-12 familiarized the crew with the geology of volcanic terrain. The astronauts used the Grover as a stand-in for the LRV during both trips to execute longer traverses than could be possible by walking.

I think it's cute that they called the training item Grover (which of course remained on Earth, so you can see him in Arizona these days).  But that wasn't the sole excitement on this date: not only did LM-10 arrive at the Cape, they also conducted the Launch Vehicle (LV) Electrical Systems Test¹.  There's so much to do before launch that we don't generally see or appreciate (especially stupid hoaxers).

One final note about the post title.  Thanks to Umberto Eco, I've been having illiterate fun with Latin phrases and whatnot, so I stole from Pliny the Elder², who wrote Naturalis Historia (Natural History):

47 quippe manifestum est solem interventu lunae occultari lunamque terrae obiectu ac vices reddi, eosdem solis radios luna interpositu suo auferente terrae terraque lunae. hac subeunte repentinas obduci tenebras rursumque illius umbra sidus hebetari. neque aliud esse noctem quam terrae umbram, figuram autem umbrae similem metae ac turbini inverso, quando mucrone tantum ingruat neque lunae excedat altitudinem, quoniam nullum aliud sidus eodem modo obscuretur et talis figura semper mucrone deficiat.

48 spatio quidem consumi umbras indicio sunt volucrum praealti volatus. ergo confinium illis est aeris terminus initiumque aetheris. supra lunam pura omnia ac diurnae lucis plena. a nobis autem per noctem cernuntur sidera, ut reliqua lumina est tenebris, et propter has causas nocturno tempore deficit luna. stati autem atque menstrui non sunt utrique defectus propter obliquitatem signiferi lunaeque multivagos, ut dictum est, flexus, non semper in scripulis partium congruente siderum motu.

To put it another way:

[47] It is in fact obvious that the sun is hidden by the passage across it of the moon, and the moon by the interposition of the earth, and that they retaliate on one another, the same rays of  the sun being taken away from the earth by the moon intervening and from the moon by the earth: at the transit of the former a sudden shadow passes over the earth, and in return the shadow of the latter dims the heavenly body (the moon), and the darkness is merely the earth's shadow, but the shape of the shadow is conical, resembling a spinning-top upside down, as it impinges only with its point and does not go beyond the altitude of the moon, because no other star is obscured in the same way, and a conical figure always tapers off into a point: that shadows are made to disappear by distance is proved when birds fly to extreme heights. 

[48] Consequently the frontier between the moon and the other heavenly bodies is at the point where the air ends and the aether begins. All the space above the moon is clear and filled with continual light, but to us the stars are visible through the night in the same way as other lights in shadows. And these are the reasons why the moon wanes in the night-time; but both of her wanings are irregular and not monthly, because of the slant of the zodiac and the widely varying curves of the moon's course, as has been stated, the motion of the heavenly bodies not always tallying in minute fractional quantities.

Anywayz, RIP Pliny, I know you would've loved the Apollo 13 motto: Ex luna, scientia.

1 - At least we already know "the probability of lightning damage to the vehicle hardware is deemed negligible."

2 - Not to be confused with Pliny the Younger, from whom I stole yesterday for a very lame meta joke: maxime idoneum mitteret comes from Letter LVI to Trajan.  Again, blame Eco, and my ignorance of Latin.

PS - I experienced a little pareidolia (from the Greek, not Latin): in that LRO image of the Soviet rover, it kinda seems like the tracks make a 'G', and along with a couple craters to the East (appearing like an eye and nose) look a bit like a profile of Grover the Muppet (you didn't think the Peanuts get all the fun in space, did you?)  But perhaps that's just me.