![]() "They're always a shortage of money," he says. The agency had to plan Skylab visits in 19, as well as the Apollo-Soyuz Test Project in 1975. Schuessler says NASA simply did not have the time or funds to fit in more moon landings after 1972. "Apollo was a proof that the United States was a leader in technology in space. "They'd accomplished everything they were trying to do," he says. John Schuessler, a former NASA engineer who worked on the Gemini program that came before Apollo, tells PM that the enormously successful Apollo program was ended for mundane reasons such budget decisions and NASA's research goals. The truth about why, however, isn't stranger than fiction. After Apollo 17, NASA scheduled three more missions to the Moon-18, 19 and 20-but those were subsequently grounded. The film's premise should grab the attention of conspiracy theory enthusiasts, but here's the real deal on the end of the Apollo program.įirst, yes, NASA did plan an Apollo 18. Put simply, it's The Blair Witch Project on the moon: The film claims to contain footage from NASA's archives of secret and disastrous Apollo 18 mission. This, again, is probably due to a history of violent collisions, as each impact will have brought in a large mass of rock, creating a region of denser material.Apollo 18, out in theaters on Friday, blurs the line between documentary and feature film. The gravitational data also show that the material below the lunar surface varies greatly in density. Zuber’s team found that the crust is unusually thin under all the basins created by large impacts. Because the Moon’s crust is less dense than the underlying mantle, the researchers could calculate the crust’s thickness from precise measurements of Clementine’s flight path. These variations occur because denser rock exerts a stronger gravitational pull. These materials are more abundant in the mantle than the crust.Ĭlementine’s mission scientists estimated the thickness of the crust by monitoring minute variations in the spacecraft’s orbit. ![]() Preliminary data from another of Clementine’s instruments show that the highlands inside the crater contain more iron and magnesium than highlands on other parts of the Moon. ![]() The impact may have excavated material from the lunar mantle, a layer that is thought to lie tens of kilometres beneath the Moon’s surface, says Paul Spudis of the Lunar and Planetary Institute in Houston. The extra volume of rock in the highlands is comparable to the empty space in the crater suggesting that a glancing impact might have pushed material north of the impact basin to form the highlands. The highest point on the lunar surface occurs here. The crust north of the crater may have retained another sign of the impact. This indicates that the surface cooled faster than scientists had thought. But hot rocks would have spread and flattened, and the South Pole-Aitken Crater evidently did not it has the same ratio of depth to diameter as younger craters. Researchers had thought the early lunar surface was warm and plastic. Given its great age, the depth of the giant crater came as a surprise. The researchers were able to estimate the crater’s age by counting the number of smaller craters marking its surface, which represent subsequent impacts. Zuber and her colleagues describe their findings in one of a series of reports on the mission in the 16 December issue of Science (vol 266, p 1839). It marks the impact of an object that probably measured some 200 kilometres across. “You don’t see it on a mosaic, but on a topographic map it’s striking,” says Zuber. Parts of the rim of the giant crater had in fact showed up in previous photographs of the Moon’s far side, but these images did not show clearly that the feature is a crater. The Moon is “a lot more heterogeneous and more interesting than we had thought”, says Maria Zuber of the NASA Goddard Space Flight Center in Maryland, who led one of the mission’s scientific teams. The Apollo orbiters, which scanned the surface some two decades ago, found a range of only 11 to 12 kilometres. It shows many other large basins caused by ancient impacts, and reveals that the difference in altitude between the highest and lowest points on the Moon’s surface is over 16 kilometres. Although previous spacecraft have made similar maps of the Moon’s equator, the new map is the first to give such complete coverage. This would make it the oldest feature on the lunar surface.ĭuring a 70-day visit to the Moon last spring, Clementine compiled a map of the topography of most of the lunar surface. Researchers believe that the feature, christened the South Pole-Aitken Crater, dates from a huge impact 4.3 to 3.8 billion years ago. Some 13 kilometres deep and 2500 kilometres across, it covers almost a quarter of the Moon’s circumference and is the largest and deepest crater in the Solar System. CLEMENTINE, a cut-price lunar probe run by the US, has found an extraordinary crater on the far side of the Moon.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |