Why don't we place permanent satellites around other planets?Date: Fri May 30 01:19:38 1997
Posted by WILLIAM JENNINGS
Grade level: undergrad
School: UNV. OF SOUTH ALABAMA
City: PENSACOLA State/Province: FL
Area of science: Astronomy
COULDN'T WE BUILD A SATELLITE THAT WE COULD PLACE IN A FIXED ORBIT AROUND EACH OF THE PLANETS IN THE SOLAR SYSTEM, WE COULD STUDY THE ATMOSPHERE AND SURFACE OF EACH PLANET SIMILAR TO THE WAY IN WHICH WE USE THEM TO WHATCH OUR WEATER OR SPY ON OUR ENEMIES? IT WOULD SEEM TO BE A SYSTEM IN WHICH LARGE NUMBERS OF UNIV. OR OTHER GROUPS COULD COMBINE FORCES TO STUDY AND CERTAINLY PAY FOR THE PROJECT. THE COST OF BUIDING THE SATELLITES WOULD CERTAINTLY BE MUCH LESS IF WE WERE TO BUILD A GENERALIZED TYPE OR GROUP RATHER THAN ONE HIGHLY SPECIALIZED SINGLE CRASH AND BURN SATELLITE?
We already have done this! At least, for some of the planets. For example, the amazing images being returned from Jupiter right now are from the Galileo satellite, which is performing a complex gravitational dance around Jupiter and its moons. The Mars Global Surveyor is on its way to Mars (expected to reach Mars orbit in a few months) and will also be in a permanent orbit around Mars. The Cassini probe is scheduled for launch next year and will be in permanent orbit around Saturn. The Magellan probe orbited Venus for over a year and returned a huge amount of information (the last thing Magellan did was to lower its orbit so much it burned up in Venus' atmosphere-- that way, we learned about the vertical structure of the atmosphere).
It is actually very hard to get a satellite to orbit another planet. The main problem is slowing the probe down enough to get it to orbit, rather than fly by the planet (like the Voyager probes did). The Global Surveyor on its way to Mars will actually dip into Mars atmosphere to slow itself down (like the rocket did in the movie "2010"). Plus, of course, space probes are expensive ventures in the first place. But I bet that within the next 50 years we'll have had probes orbiting every planet in our solar system.
The web is loaded with information about the probes mentioned above. Do a web search with the probe name as a keyword (and also include "NASA" and the planet name to make the search faster) and you'll see lots of places to read about this.