New Mars Forums

Why would it take two years to get to Mars? Are they planning to use ion propulsion?

Similar idea, though.

BTW, they also did it to the Apollo ALSEP stations.

Wouldn't any probe be crushed and/or melted long before it got anywhere near Jupiter's core? If so, then unless somebody invented something like the semi-magical "Unobtainium" metal used for the mole vehicle in the movie "The Core" it will probably be quite a while before any probe gets even a fraction of the way to Jupiter's core. 

Is that white ring that can be seen in the distance in the image below (from Sol 398) the Vostok "crater"?

(There are much closer images for Sol 399. For example, http://marsrovers.jpl.nasa.gov/gallery/ … R.JPG]this one.)

The point of mentioning the Teneriffe tragedy was to point out the difference in the survival rates. Despite the horrific loss of life, some people survived. However, they only survived if they happened to be a passenger on the plane moving down the runway at a few miles per hour. There were no survivors from the one careering down the runway at full belt.

You would have to expect the same thing would occur with a shuttle plummeting earthwards at hundreds of miles an hour.

Two shuttles have been lost in fatal accidents in a little over 20 years. How many models of commercial aircraft can boast that record?

As I understand it aircraft of the same model are grounded, at least in cases where investigators suspect the cause to be due to mechanical or airframe problems. (In those circumstances to allow similar craft to stay in service would be irresponsible.)

The reason such groundings does not impact as much on world air travel is that the world's air travel industry is not dependant on a single make or model of aircraft.

Imagine what would happen if the only kind of aircraft in service (at least in non-Russian airlines   were Boeing 747-400 series planes and all those planes had to be suddenly grounded due to an air tragedy...

NASA's folly was to put almost all its eggs in one shuttle-shaped basket. It had no contingency plan in place for dealing with vehicle losses. As far as I can see it still does not. In fact it is again putting all its eggs in one basket with this plan to retire the shuttles to make way for this new gee-whiz CEV, just as the arrival of the shuttle led to no more Saturn Vs being built. Sooner or later one of the CEVs is going to be lost due to an accident. That is an inevitability. It may not happen for a decade or two, but it will happen eventually. No one can guarantee 100% reliability, any more than anyone can guarantee that there will be more fatal aircraft incidents. When the tragedy happens all the remaining CEVs will probably be grounded, just like all the remaining shuttles were grounded after the Columbia accident. Imagine what is going to happen should there be, by then, human beings at a base on the moon dependant on those CEVs to deliver supplies.

No, the reality is that NASA only has three shuttles left, with no prospect of Congress funding the construction of any more. (The CEV is now seen as the great white hope for American human spaceflight.) The loss of another would leave only two left, imposing a further burden on maintaining its schedule.

As to your views about NASA (and/or Congress and/or the president) retiring the remaining shuttle post-haste should a third shuttle be lost, I take it you will also be expecting the same three-fatal-crashes policy be applied to aircraft and motor cars. If (say) three Boeing 747s over a 20 or 30 years period, or three Toyota Camrys crash over such a period, with the loss of all onboard, those models should be immediately withdrawn from sale, the skies, and the roads. To paraphrase your words, "the public would look at three lost [aircraft or motor cars], not this percentage or that percentage".

In other words, it would not matter one iota that there were hundreds of 747s and millions of Camrys in service, the vast proportion without any fatal accidents. What would matter more was the loss of those three.

If on the other hand that is not the sort of policy you would want to see applied to aircraft or motor cars, why then should anyone insist it be applied to the shuttle? (And, presumably, to the CEV when it comes into service.)

Thousands of people die on the world's roads every year. Hundreds die in plane accidents. Yet the cars stay on the roads and the planes still fly, with the crashed ones replaced and faults in the remainder fixed (often via expensive mass recalls in the case of cars).

Uh, a 20% launch failure rate would suggest that 20 out of every 100 launches ended in failure. Similarly, a 40% failure rate would mean that almost half had failed!

I rather doubt that is what you were intending to say.

With over 110 shuttle flights--that figure, BTW, is taken from http://www-pao.ksc.nasa.gov/kscpao/shut … .html]here and http://www-pao.ksc.nasa.gov/kscpao/shut … c.htm]here --the loss of two flights would put the failure rate of somewhat under 2%.

True, there are only a small number of shuttles, two out of 5 (ie not counting "Enterprise") of which (40%) have been lost. But that is not a "launch failure" of 40%! The Challenger, for instance, had 9 successful launches before it exploded in 1986. The Columbia had nearly 30.

Then I guess that must be Tennessee Valley we can see peeking over the ridge crest at the bottom of the following pair of navcam images, one from Sol 390 & the other from 392.

Who knows?

According to http://www.astrobio.net/news/modules.ph … thold=0]an expert interviewed by Astrobiology Magazine the source of Titan's methane is "still a mystery" (though he also adds that the "Huygens data are expected to reveal the secret, in time").

(Incidently, he also adds an interesting tidbit re that methane: for various reasons--eg the solar ultraviolet flux--the "lifetime of methane in Titan's atmosphere is approximately ten million years, compared to 300-600 years on Mars".)

If Hubble is so completely obsolete why are astronomers still queuing up to use it? Shouldn't those same people be queuing instead to use those shiny new (ground-based) scopes?

I don't agree with everything the author of that piece said. Parts of it sound an awful lot like sour grapes, and some of it--eg "this inept, anti-intellectual, reactionary, elitist approach to showing the taxpayers what their euros bought" and "[t]hey may superficially look like modern liberal states, but the old habits can still be found if you scrape off the camouflage. The people in charge no longer wear plate armour and mostly don't inherit their jobs, but they are still aristocrats at heart"--would probably be regarded in most places, let alone Europe, as bordering on the offensive. (Indeed, one can almost detect a hint of aristocrat-like intellectual snobbery.)

That said, he seemed to be right about the clapping (if you tune in to http://esamultimedia.esa.int/video/huyg … .wmv]press conference 2 from the http://www.esa.int/SPECIALS/Cassini-Huy … x.html]the ESA's Huygen's page-- it's 1.7 mb & you'll need Windows Media Player--it does, at one point--annoyingly--seem to go on forever, as if the assembled boffins having earnt their day in the sun wanted to bask in the glory; which to be fair was certainly well-deserved and only their due, but it sure tested the patience of those of us listening in ) and the showing of the pics.

But I guess the ESA still needs a few lessons on how to run a media event, it doubtless not having had as much experience at such things--at least all by itself--as NASA & JPL.

Some of those "white streaks", such as the ones over on the upper left of the pic below, look more like surf breaking against a shoreline.

That could, however, be merely an illusion. There hasn't been enough resolution in the images released thus far to be able to tell.

The Internet is a mixed blessing. Simply because somebody has put up a webpage on a particular topic does not necessarily mean that the information there is correct, much less up-to-date.

In fact in one respect the Internet is becoming a little too convenient. There seems to be a growing tendency among some students to feel they do not need to write anything original of their own at all. All they need do is get onto the Internet, find a paper somebody else has written on the topic their teacher has asked them to write on, then put their own name to it and hand it in as their own work.

There has, for example, recently been a major scandal about this at the University of Newcastle in Australia involving more than a dozen  post-graduate students attending an overseas campus handing in assignments largely taken from other sources yet presented by them as their own original work. See, for example, http://www.smh.com.au/articles/2004/09/ … =true]this link. (The scandal, BTW, is no longer that the students committed plagarism. It is that after a diligent lecturer found them out and gave the lot of them a mark of zero pressure was brought to bear on his superiors to overrule him and give them passes instead. Those superiors are now under investigation.)