Odyssey Arriving at Mars Tonight 195
moloader writes: "Odyssey will arrive at Mars on October 24, 2001, 0230 Universal Time (October 23, 7:30pm PDT/ 10:30pm EDT). As it nears its closest point to the planet over the northern hemisphere, the spacecraft will fire its 640-newton main engine for approximately 19.7 minutes to allow itself to be captured into an elliptical, or looping, orbit about 20 hours long. Go Mars!"
Orbit (Score:4, Informative)
If all works well, that's what'll make this mission a success - the aerobraking technique means significantly lower fuel requirements, which makes for a lighter and thus less expensive mission.
Let's hope everything works right this time!
About the dust storm (Score:2, Informative)
Re:Looping orbits? (Score:3, Informative)
All orbits (about a single body) are conic sections, not necessarily ellipses. Given just barely enough energy to escape the body results in a parabolic orbit, and having excess energy results in a hyperbolic one. If the orbit is 'captured,' it has an elliptical shape.
I agree though, that 'looping' and 'elliptical' shouldnt be used as synonyms.
Re:Be careful (Score:5, Informative)
Actually, we don't, that's one of the things this probe has been sent to determine. There is an ambiguous but intriguing body of evidence that liquid water may once have flowed on Mars' surface, but what water remains is yet to be determined.
We have known for some considerable time that Mars has a very thin atmosphere composed primarily of carbon dioxide. It is less than 1% as thick as Earth's atmosphere.
Your chain of reasoning is getting increasingly tenuous.
Odyssey is an orbiter, not a lander. It will never come in contact with the planet. Even if the worst happens, like it did with Mars Climate Orbiter in 1999, the thin Martian atmosphere is still thick enough to ensure that nothing uncharred reaches the surface. All landers are thoroughly sterilized before leaving Earth.
Life cares about water (Score:2, Informative)
Learning where the water is is a necessary prerequisite to finding what life may still exist. If there is life still there, it will be close to water. Water is easier to find that scant traces of life. Therefore, find the H2O, and you actually have a chance of finding something else.
NASA sent only two probes to Mars in the 70's, Viking 1 & 2. It has firm plans to send at least one probe every two years until at least the end of the decade. Considering the budget they operate within, I think they're doing a damn good job.
What it's doing there (Score:5, Informative)
High Res Spectrometers
This baby has two spectrometers, one in infrared for working out the mineral composition of the surface to a resolution of 100 metres [nasa.gov], and one in gamma rays, for working out how much hydrogen there is near the surface [nasa.gov], and consequently how much rocket fuel they can make in different places if/when they land.
Comms satellite It acts as a relay between the surface and the Earth, so any new probes (like the twin rovers due to take off next year) wont have to carry big dishes and radios.
All this and more on the website [nasa.gov].
Re:Far out (literaly!) (Score:2, Informative)
In order to get anywhere we need to approach the speed of light or even exceed it (or better yet, make the whole thing about space/time irrelevant, but that is sci-fi for the time being)
You ain't just whistling Dixie when you say it's science fiction. The fastest propulsion system proposed that we're fairly sure would work is Orion, which uses a chain of mini atomic bombs to get to 10% of c. Don't even think about trying to build it with todays technology. Anything else is currently just fantasy.
We don't need to get close to the speed of light for travel within the inner Solar System. If NASA felt that public opinion would tolerate it, they could use nuclear rockets, in which an atomic reactor was used to accelerate the fuel. That is the technology, which we could start building today, that will make travel to and from Mars feasible. We are not, in my opinion, going to get to Mars with conventional rockets.
Since you're going to site... (Score:2, Informative)
specially the mars global surveior's one, with cool hi-res pics of the "martian face". the link is here:
http://mars.jpl.nasa.gov/mgs/msss/camera/images/m
more than just NASA in the history of space.... (Score:2, Informative)
"They are the only organization that's consistently flying commercial payloads to the orbit. "
Hmmm, I think the guys at ESA may beg to differ. I think the guys on the Space Station are probably grateful that a place a wee distance from the USA called the Baikonur Cosmodrome, Kazakhstan exists and regularly sends up Soyuz taxis. I reckon there's more than just NASA in the history of space.... (not to belittle their great work, but have some perspective, eh?)
BTW is it only the Americans who use imperial rather than metric units, or are there other countries who also use a non-metric measuring system?
Problems are less severe than you paint them. (Score:5, Informative)
Getting to another star system would require near-C travel, but getting to other planets certainly doesn't. Chemical rockets can get just about anywhere in the inner solar system in a couple of years, and anywhere in the outer solar system within about five years.
Use an ion drive, and you can get just about anywhere within 1-2 years.
Sure, you won't be commuting to Mars for the weekend, but this is certainly good enough for colonization and trade. Think back to the old days of wooden ships on Earth.
Second humans are really not meant to be put in space. We need to adapt, and we need to adapt in a serious way. Most of our body is made up of this little molecule H2O, and we need lots of it to survive. Water is not easy to get in space! Food is another problem. Another is that the human bonestructure degenerates in space.
Humans aren't going to change their basic structure. We can, however, build contained environments that can support us.
Water isn't a problem. We already have water-reclamation systems that are perfectly efficient (we just don't use them because they're expensive). Your ship is air- and water-tight - you won't lose any mass to space.
If you have a big enough ship, food isn't a problem - grow it the old-fashioned way. Or stockpile a year's worth of army rations (this will take mass, but not an unmanageable amount of mass; it's just probably cheaper to grow food).
Gravity similarly isn't a problem. You can either live with bone degeneration, or you can connect two ship parts with a long cable and spin them to get a wonderful simulation of gravity and avoid all zero-g related health problems.
In summary, I don't think we need any new magical technology for in-system space travel. We have pretty much everything we need already.
Re:Looping orbits? (Score:3, Informative)
All orbits are elliptical, anyway.
Actually, orbits are only elliptical around isolated, spherically symmetric objects in Newtonian gravity. Planets are neither isolated, nor spherically symmetric, and gravity is not Newtonian :-) In the real universe, planets are approximately oblate spheroids with "small" surface ripples, like mountains, valleys, etc, which result in radial variations that make individual orbits look like "wavy ellipses" (which is actually a major source of systematic error in the GPS system that needs to be regularly corrected); further, the non-Newtonian nature of gravity (read General Relativity) causes orbits, even around perfectly symmetrical objects, to not close into ellipses, but to precess with time. And there are all sorts of other effects that you need to worry about (other planets, the sun, atmospheric drag, etc. etc. etc.) that further modify the orbit of spacecraft, guaranteeing that they're orbits won't actually look anything like ellipses on all but an "average basis" over a few orbital periods.