HUMAN ARTIFACTS ON THE MOON ------------------------- John Pazmino NYSkies Astronomy Inc firstname.lastname@example.org www.nyskies.org 2009 October 9
Introduction ---------- There swelled up during 2009 August and September a renewed curiosity about the remains of human objects on the Moon. This was sparked largely by the impending deliberate impact of LCROSS in crater Cabeus A and the photos of Apollo spacecraft taken by LRO in July. When I inquired I found there was no authoritative roster of artifacts placed on the Moon! There are articles about the touchdown or crash of specific craft and many tables of the selenographic location of Apollo landers. The table I assembled here banks off of one from Wikipedia and supplemented by other sources. It is NOT a sanitized washed thru set of data. I discuss the reasons for this situation below, but for now the locations given here are well within precision to aim at with home telescopes from the ground. At a starviewing session you can explain that the scope is centered on the spot of such-&-such spaceprobe.
Lunar lat-lon ----------- It seems natural to establish on the Moon, as a globe, a system of latitude and longitude like on Earth. From the early days of selenography, maps of the Moon regularly were girded with lat-lon lines, by which to scale off the selenographic location of lunar features. It seemed simple enough once you define the poles and equator of the Moon and select a zero point for longitude on that equator. As history fell out, selenographers adopted various locations for the lunar poles and equator. This resulted in annoyingly different schemes of lat-lon. The discrepancies from author to author are slight, not enough to mislead a home astronomer, but they are dead dangerous for local navigation on the lunar surface. Matters are worse when the author does not state clearly his selenographic system, control as its called on Earth, so that a reader may make adjustment to some other control.
Surface scale ----------- Because the Moon stays about the same distance away from us in a nearly circular orbit, angular measures on the lunar ground translate into fixed angular extents as seen from Earth. The greatest deviation from the mean values is about +/-5%. On the solid ground of the Moon angular distances on it equate to linear distances in kilometers. You can relate a feature on the Moon with some Earth feature, like a county or state. Many lunar observers actually have photocopies of a county or state roadmap to match the scale of their lunar atlas for exacta mente this purpose. One surface degree spans pretty nearly 30 kilometers and subtends 16 arcseconds from Earth. This is near the resolution limit of handheld binoculars. 0.1 degree equals quite 3 kilometers or 1.6 arcsecond. This is the accuracy of the coordinates in the table below and is near the resolution limit of a small home telescope. The lunar terminator creeps over the ground at about 1/2 surface degree per hour or 15 kilometers. Over a full day, the migration is about 12 degrees or 360 kilometers. Mind well that foreshortening near the limb of the Moon compresses distances radially, in addition to overlapping the landscape features.
Longitude ------- In all selenographic schemes the lunar latitude is conceptually the same. Latitude is the angular distance from the equator to the given point, measured in degrees of arc. This is parallel to latitude on Earth, with, as example, New York sitting at latitude 40.7 degrees north of the equator, The polarity of latitude is, like on Earth, denoted by either N/S or +/-. Longitude on the other hand has many dimensions. These include, all banked off of a zero meridian in the center of the lunar disc: +/- from 0, thru 90 degree at the mean limb, to 180 at the far side central emridian. This is similar to the usual way longitude is stated on Earth. The far side meridian corresponds to the 180th meridian in the Pacific Ocean. + all around the globe thru 360 degrees. This is uncommon on Earth but is easier to use in navigational maths. The same as the other two but in the OPPOSITE direction. One author will call + to the east while an other will put + to the west. A similar confusion occurs when setting a computer astronomy program for your location on Earth. The longitude may be + for E or + for W. New York's longitude can be, depending on the instant program, +286.1 or -286.1 degrees or +73.9 or -73.9 degrees. If the author is vague about his convention, you have to test each one to see which works correctly. The wrong longitude will throw your sky map out of synch with your local time.
East and west ----------- The use of E/W can be just as miserably confusing. This comes about from the two distinct disciplines studying the Moon, astronomy and astronautics. The astronomer looks at the Moon like a disc on the celestial sphere. The directions on this disc match those on the sky. The Moon circulates by diurnal motion from east to west. She migrates thru the zodiac from west to east. Therefore, with north at the top, east is at the left and west is at the right. The astronautical method treats the Moon like a globe in space. With north up, east is to the right and west is to the left, like on an Earth globe. The situation is sketched here.
N --- / \ / \ astronomical E | lunar disc | astronomical W astronautical W | lunar globe | astronautical E \ / \ / --- S
You may read in one work that crater Grimaldi is near the eastern limb and in an other work it's near the western limb. Mare Orientale (Eastern Sea) is near either the eastern or western limb. You must know what the author means by east and west. A lesser hiccup is the inversion of the Moon from the astronomer's convention of south at the top to the astronaut's north at top. By now astronomers are fluent with both orientations. Astronomy books may have the Moon illustrations in either orientation. Computer programs for lunar astronomy generally allow the display in either polarity.
Selenometry --------- If this is not a bona fide word yet, now with lunar explorations ramping up, it should be one. It's the methods and techniques of determining the selenographic coordinates of points on the Moon. Its analog on Earth is, ahem, geometry. Traditionally we got a coordinate by banking off of nearby features of accepted location. This is like lining up various shoreline features from a boat and laying out the boat's location on a marine navigation map. It is also like the surveying of property by aligning with adjacent lands, the metes-&-bounds method. This method works when the view of the feature is more or less vertical, like in the middle of the lunar disc. When this is tried on points around the limb, severe forshortening and overlapping of landscape features makes confident measurements really tough. The Mare Orientale syndrome can set in. An other problem arose with the global view of the Moon from spacecraft. The Moon is not a globe but a triaxial figure with the long axis aiming toward Earth. Along this axis, from Earth's view, the Moon does look pretty circular and, by inference, globular. Since all of the millennia of topographic mapping experience we enjoy is based on an awfully spherical Earth, we had a lot of new learning when now confronted with a triaxial ellipsoid. A gross example we faced was for the irregular moons of other planets and for asteroids. They are no way near 'round' for any conventional lat-lon system. In the stead an ENCLOSING sphere is set around the body and its topography is radially projected outward onto it. The coordinates are taken off of the projected image of the body on this outer sphere.
Elevations -------- There is no 'sea level' on the Moon, in spite of the recent confirmation of finding some water molecules up there. Even on Earth, the 'sea level' varies from place to place due to Earth rotation. The centrifugal and Coriolis forces distort the level so there are several base elevations in use from country to country. This is why when you initialize your GPS navigator, you must select the sea level, datum as its called, to obtain correct elevations. We can ignore absolute elevations, above the appropriate sea level, because we are concerned with pieces of spacecaft on the ground. The local elevation is zero, even it the pieces sit in a deep basin or on a high mountain. In engineering on Earth, we are almost always dealing with relative elevations, except for structures actually at the sea like breakwaters or dikes. A dam crest amy be noted on its plan at elevation 237.8 meter, but this does not mean the dam is that tall from its base or from the river bed. This number is used to look after the water level behind the dam, which ideally must stay below the crest. Water spilled over the crest is lost for electric produvtion and water supply, for example. Seeing the location of a remains when the territory is in profile, around the lunar limb can be tricky. The selenographic lat-lon is no longer a point on the lunar disc but a line with radial extent. We may have to inspect the floor of a deep crater or the slope of a tall mountain along that line. With no sea level as such, selenographers adopted various datums, all happily true spheres. They are based on the idea of building a model of the Moon from clay. Start with a globe of wood and lay clay on it to sculpt the lunar topography. To avoid digging into the wood globe, the arbor as it may be called, to represent low topography, the globe is small enough to accommodate the lowest depths expected on the Moon. With the Moon a three-way ellipsoid, some parts register insanely high elevations, requiring thicker clay to model. Other areas have only shallow elevation, for representing with thin clay. The trouble is that over the years various radii and centering of this arbor sphere were used, defined from different physical concepts. Elevations from one source can be far off from those of an other. The mountain was not so badly measured. It's merely measured from a different depth under it.
Relief ---- Relative elevations, banked off of a surrounding flat area or particular landscape feature, are far easier to determine. Much of the faculty to measure relative elevation, the relief profile, comes from the lunar libration. Since we can not arbitrarily shift our viewpoint, as we can do on Earth by going to a new spot to take measurement, we exploit the natural shift of the entire landscape of the Moon thru its librations. Libration is the wobble, entirely apparent, of the lunar globe to tilt it north-south or east-west. This makes our viewpoint shift by the equal degree over the Moon and displacing topographic features in perspective. The amount of shift is 6ish degrees in any direction but that's enough to build a local relief of a small section of the Moon to amazingly good accuracy. Relief is important in case the remains are hidden by crater walls or valleys or laid out in the open on plateaus or highland.
Current efforts ------------- There are a few astronomers and space scientists engaged in locating spacecraft remains on the Moon for several reasons. One is make them targets for later landings, to document them or bring back pieces for study back on Earth. An other is to define the remains as cultural places to protect against molest from later explorations. The work is tough going due to the haphazard way coordinates were determined in the earlier years of lunar exploration. In some cases they were picked off of a full-Moon map of the Moon under a grease pen mark. In others they were the intended target point with no indication if the craft actually landed there or some remote else where point. Many spacrcraft are lost on the Moon. This happens when a probe loses signal and is no longer tracked or controlled. It could be captured by lunar gravity in a chaotic manner. At some later date its trajectory intersected the lunar ground, causing a crash.
List of human artifacts --------------------- The list here is based on one from Wikipedia with substantial additions and modifications. Be aware that this is NOT 'the official list'. On the other hand the locations are close enough to point out in a telescope. I rounded extra decimals of coordinate to 0.1 degree to recognize their overall approximation. The longitudes are in astronautical E/W mode with east toward Neper crater, on the sunward limb for an evening crescent Moon. Longitudes greater than 90 are for objects on the lunar far side. Only one, for Lunar Orbiter 3, is close enough to the limb to rotate to the front side by libration. Of all the artifacts on the Moon today the only ones still working are the passive retroflectors left by Lunokhod and Apollo. They today are in active use for monitoring the Moon's wiggles and shudders and its gradual recession from Earth. The Moon is LOWER in mass after four decades, in 2009, of human artifacts placed there! The total mass, according to Wikipedia, is about 176 tons. The Moon rocks returned by Apollo and Luna amount to only 302 kilograms. The name of the craft differs with sources. The Apollo 11 lunar module can be called Eagle. Lunokhod 1 may be Luna 17. Kaguya may be SELENE. The date for a deliberate hard or soft landing is a firm date, often widely publicized. Those for a fall may be guesstimates because the body may have already lost control and tracking. No date is given for a lost object that presumably fell to the Moon but was never observed or planed to do so. The mass, in kilograms, of the body is cited in various ways. It can be the total mass of the body that eventually lands on the Moon, including extra fuel, cargo and riders, covers and hoods that are jettisoned separately en route to the Moon. It could be the final mass, calculated from fuel burn, removed cargo, transferred crew, discarded parts. Expect this number to vary from other sources, which often aren't too clear about what they cite. Under 'Stat' I note: --------------------- 'hard' for an intentional crash. The destroyed craft may be debris scattered around the impact point 'soft' for an intentional touchdown with a working craft. It may later return to Earth with or without leaving pieces behind 'fall' for uncontrolled crash by a craft that died in service near the Moon or was abandoned after it finished its mission 'lost' for craft with unknown landing location ---------------------------------------------- The lat-lon WILL differ from source to source for the reasons noted in previous sections. The ones here are NOT 'official', but they are close enough, within the resolution of small home telescopes, to point out the sites. ------------------------------------------------------------- Object From Landed Mass Stat Lat Lon Notes ---------- ----- ----------- ------- ---- ------ ------- ----- Luna 2 USSR 1959 Sep 13 390.2 hard 29o1'N 0o0'W Ranger 4 USA 1962 Apr 26 331 hard 12.9oS 129.1oW Ranger 6 USA 1964 Feb 2 381 hard 9.4oN 21.5oE Ranger 7 USA 1964 Jul 31 365.7 hard 10.7oS 20.7oW Luna 5 USSR 1965 May 12 1474 fall 1.6oS 25o W Luna 7 USSR 1965 Oct 12 1504 fall 9.8oN 47.8oW Luna 8 USSR 1965 Dec 6 1550 fall 9.1oN 63.3oW Ranger 8 USA 1965 Feb 20 367 hard 2.7oN 24.8oE Ranger 9 USA 1965 Mar 24 367 hard 12.9oS 2.4oW Luna 9 USSR 1966 Feb 3 1580 soft 7.1oN 64.4oW Luna 10 USSR 1966 --- 1600 lost --- 1 Luna 11 USSR 1966 --- 1640 lost --- 1 Luna 12 USSR 1966 --- 1670 lost --- 1 Luna 13 USSR 1966 Dec 24 1700 soft 18.9oN 63.1oW Surveyor 1 USA 1966 Jun 2 270 soft 2.5oS 43.2oW Lunr Orb 1 USA 1966 Oct 29 386 fall 6.4oN 160.7oE Surveyor 2 USA 1966 Sep 22 292 fall 4.0oS 11.0oW Lunr Orb 2 USA 1967 Oct 11 385 fall 2.9oN 119.1oE Lunr Orb 3 USA 1967 Oct 10 386 fall 14.3oN 92.7oW Surveyor 3 USA 1967 Apr 20 281 soft 3.0oS 23.3oW 2 Lunr Orb 4 USA 1967 Oct 31 386 lost --- 1 Surveyor 4 USA 1967 Jul 17 283 fall 0.5oN 1.4oW IMP-E USA 1967 --- 104.3 lost --- 1 Lunr Orb 5 USA 1968 Jan 31 386 fall 2.8oS 83.1oW Surveyor 5 USA 1967 Sep 11 281 soft 1.4oN 23.2oE Surveyor 6 USA 1967 Nov 10 282 soft 0.5oN 1.4oW Surveyor 7 USA 1968 Jan 10 290 soft 40.9oS 11.5oW Luna 14 USSR 1968 --- 1670 lost --- 1 Ap10 Ascnt USA 1969 --- 2211 lost --- 1, 10 Luna 15 USSR 1969 Jul 20 2718 lost --- 1 Apollo 11 USA 1969 Jul 20 2034 soft 0.7 N 23.5oE Ap11 Ascnt USA 1969 --- 2184 lost --- 3, 10 Apollo 12 USA 1969 Nov 18 2211 soft 3.0oS 23.4oW Ap12 Ascnt USA 1969 Nov 20 2164 hard 3.9oS 21.2oW 10 Luna 16 USSR 1970 Sep 20 5727 soft 0.7oS 56.3oE 3 Lunokhod 1 USSR 1970 Nov 17 5600 soft 38.3oN 35.0oW 4 Ap13 SIVB USA 1970 Apr 14 13454 hard 2.8oS 27.9oW 5 Luna 18 USSR 1971 Sep 11 5600 soft 3.6oN 56.5oE 9 Luna 19 USSR 1971 --- 5600 lost --- 1 Ap14 SIVB USA 1971 Feb 4 14016 hard 8.1oS 26.0oW Apollo 14 USA 1971 Feb 5 2144 soft 3.6oS 17.5oW Ap14 Ascnt USA 1971 Feb 7 2132 hard 3.4oS 19.7oW 3, 10 Ap15 SIVB USA 1971 Jul 29 14036 hard 1.5oS 11.8oW Apollo 15 USA 1971 Jul 30 2809 soft 26.1oN 3.6oE Lunr Rover USA 1971 Jul 30 462 soft 26.1oN 3.6oE Ap15 Ascnt USA 1971 Aug 3 2132 hard 26.4oN 0.3oE 3, 10 Ap15 sat USA 1971 --- 36 lost --- 1 Luna 20 USSR 1972 Feb 21 5727 soft 3.6oN 56.5oE 4 Ap16 SIVB USA 1972 Apr 19 14002 hard 1.3oN 23.8oW Apollo 16 USA 1972 Apr 20 2765 soft 9.0oS 15.5oE Lunr Rover USA 1972 Apr 20 462 soft 9.0oS 15.5oE Ap16 Ascnt USA 1972 --- 2138 lost --- 3, 10 Ap 16 sat USA 1972 --- 36 lost --- 1 Ap17 SIVB USA 1972 Dec 10 13960 hard 4.2oS 12.3oW Apollo 17 USA 1972 Dec 11 2798 soft 20.2oN 30.8oE Lunr Rover USA 1972 Dec 11 462 soft 20.2oN 30.8oW Ap17 Ascnt USA 1972 Dec 15 2150 hard 20.0oN 30.5oE 3, 10 Lunokhod 2 USSR 1973 Jan 15 4850 soft 25.9oN 30.5oE 6 RAE-B USA 1973 --- 328 lost --- 1 Luna 22 USSR 1974 --- 4000 lost --- 1 Luna 23 USSR 1974 Nov 6 5600 soft 12o N 62o E 9 Luna 24 USSR 1976 Aug 18 5800 soft 12.8oN 62.2oE 4 Hagoromo Japan 1990 --- 12 lost --- 7 Hiten Japan 1993 Apr 10 143 hard 34.3oS 55.6oE Prospector USA 1999 Jul 31 126 hard 87.7oS 42.1oE SMART-1 ESA 2006 Sep 3 307 hard 34.4oS 46.2oW MIP India 2008 Nov 14 35 hard 89.9oS 0.0oE 8 Okina Japan 2009 Feb 12 53 fall 28.2oN 201.0oE Chang'e-1 China 2009 Mar 1 2000 hard 1.5oS 52.4oE Kaguya Japan 2009 Jun 10 1984 hard 65.5oS 80.4oE Centaur USA 2009 Oct 9 2000 hard 84.7oS 48.7oW 11 LCROSS USA 2009 Oct 9 880 hard 84.7oS 48.7oW 11 ----------------------------------------------------------- Notes --- Most of these notes accompany the Wikipedia list and are helpful for understanding some of its entries. I simplified some wording and added a few more notes. 1 - Spacecraft was in lunar orbit after mission was completed. It is assumed to decay from orbit and crash into the Moon at an unknown location. 'Lost' is not the same as a mission failure! 2 - Apollo 12 returned about 10kg of Surveyor-3's landing mass of 302kg to study the effects of long term exposure to the space environment 3 - The ascent stage of Apollo 10 was commanded to leave lunar orbit and enter solar orbit. The Apollo 11 ascent stage was left in orbit. Its orbit decayed and it crashed onto the moon at an unknown location. The Apollo 16 ascent stage failed to crash onto Moon when commanded. It decayed from orbit at a later date and crashed at an unknown location. The ascent stages of Apollo 12, 14, 15, and 17 were deliberately crashed onto the Moon. Apollo 13's complete Apollo Lunar Module reentered Earth's atmosphere after serving as a lifeboat during the aborted mission. 4 - Luna spacecraft mass is for both ascent and descent stages, though only the descent stage was left on the moon. 5 - The S-IVB impacted the lunar surface at 20:10 EST on April 14 at a speed of 259 meters per second, 137.1 kilometers from the Apollo 12 seismometer. 6 - Lander and rover weighed 1814 kg. The rest assumed to have decayed in orbit and impacted the moon. 7 - Hagoromo was injected into lunar orbit in 1990, assumed to decay from orbit and crash at an unknown location. 8 - Moon Impact Probe was crash-landed on the Shackleton crater by the Chandrayaan-1 orbiting spacecraft. 9 - Craft was damaged during landing and could not return a sample. 10 - Some sources list the crashes of the 'lunar module', which destroyed the craft. The part that crashed was the ascent stage, carrying the astronauts back to the Command Module. This, the ascent stage of the Lunar Module, was set free to fall to the Moon after its crew moved out of it. 11 - Centaur was the 2nd stage rocket of the LCROSS and LRO spaceprobes. LRO went into lunar orbit on 2009 Jun 23. Centaur was deliberately crashed into crater Cabeus to create a debris cloud. LCROSS examined the impact plume for water ice, then crashed several minutes later at nearly the same spot. Original target was Cabeus A crater, changed to Cabeus.
Apollo sites ---------- The enduring fascination of the Apollo missions generated intense desire to pinpoint exactly the landing sites of each flight. In July 2009 the new Lunar Reconnassaince Orbiter took pictures of the sites, confirming their reality. Because these were test pictures during the shakedown phase of the LRO mission, there was not yet an improvement in their selenographic locations. The initial pictures were of 'low' resolution, about 2 meters. This was good enough to identify the larger pieces of each flight and suggest smaller items. Production pictures starting in late 2009 will deliver the full detail of about 80 centimeters. The Apollo coordinates here come from NASA with its explanation. NASA has no real reason to improve these, except as a collateral benefit from the LRO data, and considers these the best available set of Apollo coordinates there is:
= = = = =
'The longitude and latitude values associated with those points depend on our evolving understanding of the shape of the Moon and have been subject to revision. In the following table, the LM coordinates listed in the second and third columns have been adapted from a table in Zimbelman's paper. These values agree with those given in the various Mission Reports issued shortly after each flight. 'The values in the fourth and fifth columns come from a 1987 paper by Davies et al as listed on the National Space Science and Data Center webpage. 'The Apollo era values were derived, in the case of Apollo 15, with reference to Rima Hadley Lunar Photomap.
= = = = =
---------------------------------------------------------- Zimbelman's coords Davies's coords Lat deg N Lon deg E Lat deg N Lon deg E ------------ --------- --------- --------- --------- Apollo 11LRRR - - +0.67337 +23.47293 Lunar Module +0.6875 +23.4333 +0.67409 +23.47298 ----------------------------------------------------------- Apollo 12 ALSEP - - -3.01084 -23.42456 Lunar Module -3.1975 -23.3856 -3.01381 -23.41930 ----------------------------------------------------------- Apollo 14 LRRR - - -3.64422 -17.47880 ALSEP - - -3.64450 -17.47753 Lunar Module -3.6733 -17.4653 -3.64544 -17.47139 ----------------------------------------------------------- Apollo 15 LRRR - - +26.13333 +3.62837 ALSEP - - +26.13407 +3.62981 Lunar Module +26.1008 +3.6527 +26.13224 +3.63400 ----------------------------------------------------------- Apollo 16 ALSEP - - -8.97577 +15.49649 Lunar Module -8.9913 +15.5144 -8.97341 +15.49859 ----------------------------------------------------------- Apollo 17 ALSEP - - +20.18935 +30.76796 Lunar Module -20.1653 +30.7658 +20.18809 +30.77475 -----------------------------------------------------------
Conclusion -------- The notion that space travel is so exact and precise a discipline is false, to be gentle about life. In what looks like so simple a task to capture the coordinates of a spacecraft sitting on the Moon there are many problems. Unless there is a compelling reason to determine 'definitive' values, it is unlikely the effort will be expended any time soon.