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Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Thu Jan 27, 2011 9:04 am
by JohnD
Hank,
My previous reply was lost when the website lost track of my identity.
Suffice it to say that it's time YOU presented some evidence.
You show the slow impact simulations; you do the calculations that allow a stone to roll in micro gravity with enough force to indent a landscape to a depth of many meters over kilometers of distance without rebounding into space; you provide evidence from elsewhere in the cosmos of events that could back up your assertions. Because so far, that is what they are, beliefs based on no evidence.

John

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Sat Feb 26, 2011 8:11 pm
by JohnD
Al,
Hank must be composing a definative rebuttal.
So while he's doing that, have a look at today's HiRise pic, "Conjoined Triplets": http://hirise.lpl.arizona.edu/
There's a link there to Conjoined twins too.

Three impact craters, so close they have common walls. And they look like a short groove, that anyone who ignores the physics of microgravity could mistake for rolling asteroid's groove.

John

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Tue Mar 08, 2011 10:15 pm
by JohnD
hank,
Thought you might be interested by a recent HiRise pic from thr martian surface.
http://hirise.lpl.arizona.edu/ESP_015900_1465

Shows stones that really have rolled across the surface, leaving a trail. Of course, that surface is at a steep angle to local gravity 'down', which is what has 'powered' this event.
You will notice that it leaves a trail of marks, that resemble craters, but are the reuslt of a stone rolling across a sandy surface, exactly as you propose for Phobos. But look closely; the initial, higher marks are further apart, as the stone is moving faster, and the marks are neither grooves nor circular craters, They show the curving irregular apperance that an irregular stone will leave as it rolls along.

None of those features are preent in the Phobos markings, which would indicate a different process to a rolling stone.

John

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Mon Oct 17, 2011 3:37 pm
by neufer
APOD Robot wrote:Image Phobos South Pole from Mars Express

Explanation: Where on this moon would you land? The moon pictured above is not Earth's moon but Phobos, the closest moon to the planet Mars. Phobos is so close to Mars that it is expected to break up and crash into the red planet within the next 100 million years. Earlier just this year, however, ESA's Mars Express mission took detailed images of the area surrounding Phobos' South Pole. Visible on the small moon's unusually dark surface are many circular craters, long chains of craters, and strange streaks. Large Stickney Crater, which looms on the far right, was also visible in the corresponding North Polar image taken last year. This and other similar images of Phobos are so detailed, resolving items even 10-meters across, that they are useful for examining proposed landing sites of the future Phobos-Grunt mission. The Russian Phobos-Grunt robotic spacecraft is scheduled to launch toward Phobos later this year and return surface samples in 2014.
.
[size=200][color=#FF0000]Phobos-Grunt[/color][/size]


Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Mon Oct 17, 2011 4:21 pm
by owlice
Hahahaha!! Oh, neufer, you know I totally want that owl (minus the graduation cap)! Never occurred to me to try to crochet an owl; maybe the pattern is online somewhere. Off to Google!

ETA: Oh, lovely! This led me to this, which led me to these patterns for owlets. Given my (appallingly huge) stash of yarn, I think I can manage to make a (*cough*) few of these to donate, and then one to keep, too. Thanks, neufer; I like this a lot.

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Mon Oct 17, 2011 4:53 pm
by Beyond
Owlice, before you donate--we want pictures, to check on the 'Crochetification' of all the cute(?) little offspring you produce.

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Mon Oct 17, 2011 5:14 pm
by owlice
Well, maybe not pictures of all of them, and don't hold your breath waiting for them, as I have to finish the scarf in progress first, and then make a few more (also to give away/donate) before I move on to other things!! But make these little owls, I will!

so many projects.... so little time.....

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Tue Oct 18, 2011 5:01 pm
by BMAONE23
If make them you will, then picture them you must
Click to view full size image
:mrgreen:

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Wed Oct 19, 2011 4:00 am
by bystander


Phobos-Grunt update; lots of new images and video!
Planetary Society Blog | Emily Lakdawalla | 2011 Oct 14

Phobos-Grunt unpacked! With Yinghuo-1 and LIFE!
Planetary Society Blog | Emily Lakdawalla | 2011 Oct 18

Phobos-Grunt: The Mission Poster
Universe Today | Ken Kremer | 2011 Oct 15

Phobos-Grunt and Yinghou-1 Arrive at Baikonur Launch Site to tight Mars Deadline
Universe Today | Ken Kremer | 2011 Oct 19

Time to throw in the owl.

Posted: Fri Dec 02, 2011 8:14 pm
by neufer

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Fri Dec 02, 2011 8:27 pm
by BMAONE23
Perhaps Russia would foot the bill to send another Shuttle up to do a snag and repair mission to the Little Grunt and send it on its way

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Fri Dec 02, 2011 8:46 pm
by Chris Peterson
BMAONE23 wrote:Perhaps Russia would foot the bill to send another Shuttle up to do a snag and repair mission to the Little Grunt and send it on its way
A single shuttle launch costs about five times the entire mission cost of Phobos-Grunt. I don't see that happening. And how do you plan a repair mission when you don't even know what's wrong? And if you could repair it, where do you send it? Mars is no longer an option.

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Fri Dec 02, 2011 10:22 pm
by BMAONE23
You send up a fresh motor set with sufficient fuel source to attach to the probe so that it can still reach Mars with fuel enough to slow it back down and thereby prevent its current fuel from harming the environment

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Fri Dec 02, 2011 11:51 pm
by Chris Peterson
BMAONE23 wrote:You send up a fresh motor set with sufficient fuel source to attach to the probe so that it can still reach Mars with fuel enough to slow it back down and thereby prevent its current fuel from harming the environment
The window to get into a trajectory that will go to Mars is already passed. Remember those Hubble servicing missions? Those were accomplished with months of practice on the ground, a rich set of specialized, custom tools, and a spacecraft that was designed from the beginning to be serviced. For all practical purposes, any servicing of Phobos-Grunt that requires replacing parts is impossible. The only practical scenario would be fitting it with some kind of backpack booster to get it into a higher orbit, so there is no immediate risk of decay. And that isn't economically feasible.

In reality, the probe is extremely unlikely to cause any problems. It doesn't contain enough fuel to pose any environmental risk, outside of the tiny area where something might come down. I'm pretty sure that any rational cost/risk assessment would conclude that doing nothing at all is the best strategy.

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Sat Dec 03, 2011 9:51 am
by JohnD
But, as I said in another thread, I bet that NASA are pointing out to the US Government that, for want of a few million dollars, they could have ridden the Shuttle to the rescue of Phobos-Grunt, and even brought the probe back. The political return would have been immeasurable.

It does sound like an alternative screenplay to "Space Cowboys", but the film worked for me!
John

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Sat Dec 03, 2011 3:05 pm
by Chris Peterson
JohnD wrote:But, as I said in another thread, I bet that NASA are pointing out to the US Government that, for want of a few million dollars, they could have ridden the Shuttle to the rescue of Phobos-Grunt, and even brought the probe back. The political return would have been immeasurable.John
Sorry, but what technology do we have (or have we had) that could rescue Phobos-Grunt for "a few million dollars"? I'm certainly not familiar with it.

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Sat Dec 03, 2011 5:48 pm
by JohnD
Sorry, hip shooting at costs. NASA estimate $1.5 TRILLION per Shuttle launch over the life of the programme, but $500 MILLION at the end when all the non-recurring costs are paid.

Only $500 million!
The UK has just spent about $1.5 Bilion to mothball the aircraft carriers we have on the stocks.
John

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Sat Dec 03, 2011 5:59 pm
by Chris Peterson
JohnD wrote:Sorry, hip shooting at costs. NASA estimate $1.5 TRILLION per Shuttle launch over the life of the programme, but $500 MILLION at the end when all the non-recurring costs are paid.
Only $500 million!
Exactly. Simple shuttle missions cost about $500 million. Complex missions like those that serviced the HST cost about $1 billion.

The entire Phobos-Grunt mission funding- development and multiple year operational costs- is (or was) about $160 million. Using a shuttle mission to recover the spacecraft, or repurpose it for something like an asteroid mission, would be economic nonsense. And that's assuming it would even be feasible to do so with a spacecraft not designed to be serviced.

The reality is that when a spacecraft fails, it is almost always cheaper and smarter to just start over. BTW, this applies to the HST as well, which never should have been serviced, just replaced occasionally.

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Sat Dec 03, 2011 10:42 pm
by JohnD
Interesting PoV, Chris, rather blows the human space flight argument away.
Bit depressing, really.
Whatever happened to the "High Frontier"?
John

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Sat Dec 03, 2011 11:30 pm
by rstevenson
It only blows the human space flight argument away if you agree with Chris that dollars are the only criteria. Human beings should be in space in a big way, now and forever more, doing things that (only at first) don't make economic sense. Suggesting otherwise is short term thinking and long term folly. Suggesting otherwise is like suggesting several hundred years ago that we shouldn't bother with all those small boats that don't really accomplish anything, we should just wait until we can build the Queen Mary before we go to see what those new lands to the west look like.

But this is an old argument that can't be won because, like most such arguments, we all come to it with our opinions fully formed.

Rob

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Sun Dec 04, 2011 2:23 am
by neufer
JohnD wrote:
Interesting PoV, Chris, rather blows the human space flight argument away.
Bit depressing, really.
Whatever happened to the "High Frontier"?
  • ________ Scientific American JUNE 1960

    "Putting a man in space is a stunt: the man can do no more
    than an instrument, in fact can do less.
    "
    So said Vannevar Bush,
    chairman of the Board of Governors of the Massachusetts Institute
    of Technology, in a statement to the House Committee on Science
    and Astronautics. "There are far more serious things to do than to
    indulge in stunts. As yet the American people do not understand the
    distinctions, and we in this country are prone to rush, for a time, at
    any new thing. I do not discard completely the value of demonstrating
    to the world our skills. Nor do I undervalue the effect on morale of
    the spectacular. But the present hullabaloo on the propaganda
    aspects of the program leaves me entirely cool.
    "
Of course, humans have become much more sophisticated in the last 50 years
so it doesn't make as much sense to do things totally robotically as it used to.

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Sun Dec 04, 2011 2:36 am
by neufer
rstevenson wrote:
It only blows the human space flight argument away if you agree with Chris that dollars are the only criteria. Human beings should be in space in a big way, now and forever more, doing things that (only at first) don't make economic sense. Suggesting otherwise is short term thinking and long term folly. Suggesting otherwise is like suggesting several hundred years ago that we shouldn't bother with all those small boats that don't really accomplish anything, we should just wait until we can build the Queen Mary before we go to see what those new lands to the west look like.
It only blows the human space flight argument away if you agree with Chris that science is the primary criteria. Robots should be in space in a big way, now and forever more, doing things that (only at first) don't make economic sense. Suggesting otherwise is short term thinking and long term folly. Suggesting otherwise is like suggesting several decades years ago that we shouldn't bother with Voyager spacecraft that don't really accomplish anything important such as having men plant flags on other planets.

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Sun Dec 04, 2011 2:37 am
by Chris Peterson
JohnD wrote:Interesting PoV, Chris, rather blows the human space flight argument away.
Bit depressing, really.
Whatever happened to the "High Frontier"?
I don't think it has anything to say about human space flight at all, except that turning astronauts into satellite repairmen isn't a very good use of resources.

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Sun Dec 04, 2011 3:21 am
by BMAONE23
As these before and after Hubble images show....The trip was worth the expense to repair the Hubble
M15 before first repair mission // and after
1991
Click to view full size image
2000
Click to view full size image

Or M100 before and after
before
Click to view full size image
after
Click to view full size image

Hubble at a glance

Definitely worth the effort and expense to repair some satellites

Re: APOD: Phobos South Pole from Mars Express (2011 Jan 24)

Posted: Sun Dec 04, 2011 3:41 am
by Chris Peterson
BMAONE23 wrote: Definitely worth the effort and expense to repair some satellites
I'd say it's worth the expense to have some satellites. What made fixing Hubble kind of stupid is that the repairs cost more than a brand new Hubble. For what we spent on repair missions we could have had several telescopes up there.