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neilzero
2010-May-29, 10:48 PM
~From 'Free Mars' following is some interesting details about~ The Martian Lunar System
The discovery of "hurtling moons of Barsoom" to use Edgar Rice Burrough's colorful phrase contains a curious puzzle of literary history. The tiny moons Phobos and Deimos were discovered and named by Asaph Hall in 1877. Hall was working with the new 26 inch refracting telescope at the U.S. Naval Observatory in Washington. Beginning in August of that year Hall began a systematic search for possible Martian satellites. He found Deimos on Aug. 11 and Phobos on Aug. 18. They were named after the attendants of the God of War. Both moons are very tiny and orbit Mars quite closely which explains why they were not discovered until the late 19th Century. Deimos orbits Mars at an altitude of 23,500 km. (14,600 mi.) with a period of 30 hours and 18 minutes. Phobos, the inner moon orbits Mars at an altitude of 9400 km. (5,800 mi.) with a period of only 7 hours and 38 minutes.

The puzzle lies in the fact that Jonathan Swift (1667-1745) in his famous satire "Gulliver's' Travels" (1726) written to "vex the world" as he put it, describes Mars as having two tiny moons as Hall discovered in 1877, some 151 years later! This delightful satire certainly did vex the powers that be in the early 18th Century and is a story loved by young and old alike today. It also vexes historians to this day, how did he know? Was it just a lucky guess? Did he have access to an unusually powerful telescope during unusually good seeing conditions? We may never know. What ever the results of this puzzle, I highly recommend the original "Gulliver's' Travels" (1726), but be warned, it is not a children's story in the original like it is in some later adaptations.

Because the Martian moons orbit so close to their primary, they neatly bracket the Martian Clarke or Synchronous orbit as you can see in the map above. This fortuitous arrangement will allow resupply and shielding of a Martian Synchronous Space Station with significantly greater ease than the Terrestrial Geosynchronous equivalent being resupplied and shielded from Earth's Moon. This applies to Martian Comsats and Powersats as well. The down side of the tininess of the Martian Moons is that no Lagrange Points can be established in the Martian System.

Since the Martian Moons are actually Carbonaceous Asteroids captured from the inner Asteroid Belt millions of years ago, they are considerably richer in volatiles than the Earth's Moon. This allows them to be used as fuel depots and life support raw materials supply as well as shielding and structural materials supply for the Mars Synchronous Station, the Low Mars Orbit Station, and the Mars Colony. They would also be the primary source of carbon black for the Martian poles if large scale terraforming of Mars were ever undertaken.
~ Carbon black would work during the polar spring and
summer when the Sun is continuously up to 23 degrees above the horizon. Neil~

cjameshuff
2010-May-30, 11:22 PM
Since the Martian Moons are actually Carbonaceous Asteroids captured from the inner Asteroid Belt millions of years ago, they are considerably richer in volatiles than the Earth's Moon. This allows them to be used as fuel depots and life support raw materials supply as well as shielding and structural materials supply for the Mars Synchronous Station, the Low Mars Orbit Station, and the Mars Colony. They would also be the primary source of carbon black for the Martian poles if large scale terraforming of Mars were ever undertaken.

They are also easier to send payloads to than most asteroids or Mars itself. You can aerobrake into orbit around Mars and enter an orbit that has only a low delta-v to either Phobos or Deimos, and their small size means that there's only a small delta-v required to make a soft landing. The big downside is the long trip required. (and the variability of the Martian atmosphere...some satellites dedicated to monitoring atmospheric conditions would be a good idea)

Nowhere Man
2010-May-31, 12:35 AM
The puzzle lies in the fact that Jonathan Swift (1667-1745) in his famous satire "Gulliver's' Travels" (1726) written to "vex the world" as he put it, describes Mars as having two tiny moons as Hall discovered in 1877, some 151 years later! This delightful satire certainly did vex the powers that be in the early 18th Century and is a story loved by young and old alike today. It also vexes historians to this day, how did he know? Was it just a lucky guess? Did he have access to an unusually powerful telescope during unusually good seeing conditions?
Here's a fairly good guess: Swift was going in a geometric progression. Earth has one moon, Jupiter has four, so why not two for Mars? This was actually proposed by Kepler, and was a current popular idea. Also, since no moons had yet been discovered for Mars at the time, if they existed they had to be fairly small and close in. In fact, the real moons are closer in than Swift wrote. No need to postulate technology that did not exist at the time. If he'd had such a scope, and assuming he knew how to use it, he would have had his numbers closer to reality.

If Mars had turned out to have only one moon, or three, we wouldn't be having this discussion. Every so often, an author does get a prediction correct or partly so, purely by chance.


What ever the results of this puzzle, I highly recommend the original "Gulliver's' Travels" (1726), but be warned, it is not a children's story in the original like it is in some later adaptations.
If I may add my two cents, try to get the edition annotated by Isaac Asimov (from which I cribbed the above). The Good Doctor explains all of the bits of satire, which are making fun of institutions that for the most part are now long dead. Without such notes, unless you've some knowledge of the period, a lot of it comes across as gibberish.

Fred

Romanus
2010-May-31, 03:15 AM
^
Can only say "Ditto"; the idea that Mars must have two since Jupiter had four was already established by the time the book was written, IIRC. That they were discovered earlier is extremely unlikely; the Martian moons are tough nuts to crack (at least visually) with modern equipment far superior to anything available in the early 18th century.

Nowhere Man
2010-May-31, 03:54 AM
Back in the '60s (when I was a pre-teen) I read one of Otto Binder's UFO books. IIRC he made mention of Swift's martian moons to ask the question, "Did Swift get his information from space aliens?" :wall:

Fred

mantiss
2010-May-31, 06:46 PM
Yeah, that has bad whiffs of Von Daniken's words too :P