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Phobos-Grunt
TheChemist
post Dec 15 2005, 02:28 PM
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QUOTE (Richard Trigaux @ Dec 15 2005, 11:45 AM)
I think that if the Russians are coming to an end of their economic difficulties and come back on stage for space exploration, everybody should be happy.
*

Maybe when they 're done with their investments in the English premiership and F1, some money will be left for space exploration smile.gif
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post Dec 15 2005, 05:03 PM
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QUOTE (ljk4-1 @ Dec 15 2005, 02:25 PM)
While the Soviets never had a fully successful mission to Mars, they did have partial successes, and they did land the first spacecraft on the planet, even if they did all go bye-bye prematurely.  Of course none of them returned nearly as much data and images as the US missions.
To put it mildly, I think that's an understatement. I certainly do not want to engage in bashing the Russians -- they have some fairly top notch scientists -- but their data return via spacecraft from Mars has been much worse than "[not] nearly as much...as the US missions." I would venture a guess, without having done a bit by bit comparison, that Mars Express alone has returned more data than all Soviet/Russian Mars missions combined.
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post Dec 15 2005, 05:57 PM
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QUOTE (Richard Trigaux @ Dec 15 2005, 09:45 AM)
I think that if the Russians are coming to an end of their economic difficulties and come back on stage for space exploration, everybody should be happy.
I agree, and if/when I see hard evidence supporting this scenario, I promise to be happy. A notice in the press that some mission "seems to be on track to launch" four years from now doesn't get me too excited.
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ljk4-1
post Dec 15 2005, 08:14 PM
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QUOTE (AlexBlackwell @ Dec 15 2005, 12:03 PM)
To put it mildly, I think that's an understatement.  I certainly do not want to engage in bashing the Russians -- they have some fairly top notch scientists -- but their data return via spacecraft from Mars has been much worse than "[not] nearly as much...as the US missions."  I would venture a guess, without having done a bit by bit comparison, that Mars Express alone has returned more data than all Soviet/Russian Mars missions combined.
*


I may be wrong on this, but I remember reading that Soviet space philosophy when it came to robot deep space probes was to build them as best they could, but essentially "test" them in space. If they failed on the way, one simply pretended to the West that they never existed, learn from the mistakes if possible, and try to build a better one next time. The US view was build and test them to the max before sending them out.

This is one reason why the USSR had more launches and more failures than the US.


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tedstryk
post Dec 15 2005, 08:18 PM
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QUOTE (ljk4-1 @ Dec 15 2005, 08:14 PM)
I may be wrong on this, but I remember reading that Soviet space philosophy when it came to robot deep space probes was to build them as best they could, but essentially "test" them in space.  If they failed on the way, one simply pretended to the West that they never existed, learn from the mistakes if possible, and try to build a better one next time.  The US view was build and test them to the max before sending them out.

This is one reason why the USSR had more launches and more failures than the US.
*


That and the fact that the cover up was considered possible (even if in the end it wasn't. For example, the Mars 4-7 mission had serious computer problems, and the scientists wanted to delay, but the powers that be ordered that it go ahead, with the idea that if one of the landers managed to erp back a bit of data before its problems killled it, it would be the last chance to beat Viking. Mars-6 did return descent data, but it was very limited, and most know for an false reading from the pump for the mass spectrometer that made them think there was Argon in the atmosphere.


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RNeuhaus
post Dec 15 2005, 08:33 PM
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I think that previously Russian has failed many missions due mainly to political factors rather than technical reasons. The Soviet's leaders had made a lot of pressure and unrealistic judgment on engineers and scientists to do anything almost impossible, hurry up all things because there were a space race against the U.S. of America. to anywhere: Moon, Venus and Mars.

Then, now the view on the space is somewhat more calm than before so anybody are not in hurry to send any spacecraft to the space as a race but rather as on self pace rate in which it will guarantee a much higher mission success rate.

Hope that Russian, in that time, will manage better the space exploration programs without any kind race with any nation of Earth...rather better with more international cooperation

Rodolfo
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JonClarke
post Dec 16 2005, 12:30 AM
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QUOTE (ljk4-1 @ Dec 15 2005, 08:14 PM)
I may be wrong on this, but I remember reading that Soviet space philosophy when it came to robot deep space probes was to build them as best they could, but essentially "test" them in space.  If they failed on the way, one simply pretended to the West that they never existed, learn from the mistakes if possible, and try to build a better one next time.  The US view was build and test them to the max before sending them out.

This is one reason why the USSR had more launches and more failures than the US.
*



Don't know about the space environment test program but Moon, Mars and Venus landers were extensively tested on earth in extensive ground, drop and simulation chamber tests. It seems to have paid off with the venus landers but to with mars. Don't know why.

And yes Alex, you are a curmudgeon. I think they will pull it off. They are getting serious budget increases at last. And I don't think comparing Phobos 2 to ME is fair given that the design of ME 15 years more advanced - better compared with mariner 9 which returned lower quality and less diverse data but at lot more of it. If you are not excited by an annoucement that this mission is on track for 4 years i assume you are equaly unexcited by ML, which is also supposed to be on track for a launch 4 years from now.

Toma B: - you will find that Phobos 2 collected a lot more data than 38 pictures. There are at least 300 publications I can identify on this mission. As a sample return mission, there is no way that it can be considered a scaled down Phobos 2, given that that was did not involve sample return.

Ted: while the amount was erroneous, the interpretation of the Mars 6 lander MS data did rightly alert people to the possibility that Mars has above terrestrial proportions of Ar.

That said, the mission does scare me at bit. Hayabusa has shown how difficult small body sample return can be. I would like to see the Russians get a few more runs on the Mars board with some simple missions before trying something this ambitious. A criticism of their prevous Mars missions would be that (unlike with their lunar and venus probes) they did not iron out bugs with repeat missions but sent a succession of every more complex probes.


Jon
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Guest_AlexBlackwell_*
post Dec 16 2005, 01:52 AM
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QUOTE (JonClarke @ Dec 16 2005, 12:30 AM)
And yes Alex, you are a curmudgeon.  I think they will pull it off.  They are getting serious budget increases at last.

I sure hope you're right, Jon. Me, I've seen too many Russian "sales pitches" to be excited at this early juncture. Indeed, I've seen too many NASA "virtual slide show" missions that never left the PowerPoint file, too, and NASA has a much better track record over the past 10-15 years than the Russians!

QUOTE (JonClarke @ Dec 16 2005, 12:30 AM)
And I don't think comparing Phobos 2 to ME is fair given that the design of ME 15 years more advanced - better compared with mariner 9 which returned lower quality and less diverse data but at lot more of it.  If you are not excited by an annoucement that this mission is on track for 4 years i assume you are equaly unexcited by ML, which is also supposed to be on track for a launch 4 years from now.

Now who's making the unfair comparisons, Jon? smile.gif

At least MSL (I presume that's the mission you're referring to by "ML") has solicited and selected instruments. I'll concede, however, that that's no guarantee MSL will fly.
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edstrick
post Dec 16 2005, 06:13 AM
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The soviets and the Russians after them have had a severe problem with reliabilty in initial flights of series of spacecraft on lunar and planetary missions. After a series of sucesses and partial sucesses with the series-1 lunar missions (Luna 1 through 3, not including launch failures), they had sustained failures with the series-2 lunar series, Luna 4 through 8; before Luna 9 landed, 10-12 orbited and 13 landed.

The series 3 lunar missions started with the failure of a sample return mission (Luna 15, during Apollo 11), then succeeded with Luna 16, 2 Lunokhod rovers, 2 heavy lunar orbiters (who's science return seemed to be minimal) and 2 more successful sample returns (and 2 sample return missions that were reputedly damaged during landing attempts in the rough highlands south of Mare Crisium. On the whole, pretty successful.

Similarly, the one block-1 planetary launch and all the early series-2 planetary launches failed until Venera 4 in 1967, 5 & 6 in 69 probed the atmosphere, and finally Venera 7 landed and had a partially successful mission in 1971 (Venera 8 one opposition later was a complete success) All the series-2 Mars missions failed, though one that was launched as an engineering test after it missed the launch window to mars, Zond-3, did a successful lunar flyby. All the series-3 lander missions to Mars were failures, though the Mars 3 orbiter was a success, and the Mars 5 orbiter was a success that failed prematurely.

After failing to send missions to compete with Vikings at Mars in 75, the series-3 missions to Venus succeeded brilliantly. Venera 11 and 12 failed to turn on landed science after highly successful atmosphere descents, but 13 and 14 were full successes, 15 and 16 were successful radar orbiters (one had some problems), and Vega 1 and 2 venus landers and balloons were successful, and the Halley flyby missions were largely successful, though the imaging quality at the comet was fairly miserable (it did provide essential pathfinding targeting for Giotto).

The series-4 missions (2 Phobos missions and poor Mars 96, which was launched-to-death) failed, but the Phobos 2 mission was a substantial scientific success as a Mars orbiter before it failed during the Phobos orbit rendezvous operations. Then their budget failed.
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Toma B
post Dec 16 2005, 07:14 AM
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QUOTE (JonClarke @ Dec 16 2005, 03:30 AM)
Toma B: - you will find that Phobos 2 collected a lot more data than 38 pictures.  There are at least 300 publications I can identify on this mission.  As a sample return mission, there is no way that it can be considered a scaled down Phobos 2, given that that was did not involve sample return.
*


I have said "In the end; Phobos-1 was lost before it even reached Mars and Phobos-2 took "staggering amount of information including 38 images"...same basic design was again used on Mars-96 but it never had a chance to see Mars...."
But it wasn't data it should have colected...it was Phobos explorer and it died before almost any Phobos science was done...right?
Anyway I wish them luck with new spacecraft, first one in 10 (or so ) years...


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post Dec 16 2005, 07:50 AM
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QUOTE (RNeuhaus @ Dec 15 2005, 08:33 PM)
I think that previously Russian has failed many missions due mainly to political factors rather than technical reasons. The Soviet's leaders had made a lot of pressure and unrealistic judgment on engineers and scientists to do anything almost impossible, hurry up all things because there were a space race against the U.S. of America. to anywhere: Moon, Venus and Mars.

Then, now the view on the space is somewhat more calm than before so anybody are not in hurry to send any spacecraft to the space as a race but rather as on self pace rate in which it will guarantee a much higher mission success rate.

Hope that Russian, in that time, will manage better the space exploration programs without any kind race with any nation of Earth...rather better with more international cooperation

Rodolfo
*


I Agree with all this.
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edstrick
post Dec 16 2005, 08:17 AM
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Toma B: "....But it wasn't data it should have colected...it was Phobos explorer and it died before almost any Phobos science was done...right?...."

Wrong. The Phobos mission hopper and landers were entirely phobos dedicated, but the main mission was targeted toward both Mars and Phobos. The early part of the In-orbit phase of the mission was in an eccentric orbit doing Mars science that could not be done later (especially fields and particles science) that could not be done as well from the more circular pre-rendezvour or the nearly circular rendezvous orbit. The thermal infrared Thermoscan and Near infrared mapping spectrometer data in particular was to continue after operations at Phobos had terminated.
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RNeuhaus
post Dec 16 2005, 04:47 PM
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QUOTE (edstrick @ Dec 16 2005, 01:13 AM)
After failing to send missions to compete with Vikings at Mars in 75, the series-3 missions to Venus succeeded brilliantly.  Venera 11 and 12 failed to turn on landed science after highly successful atmosphere descents, but 13 and 14 were full successes, 15 and 16 were successful radar orbiters (one had some problems), and Vega 1 and 2 venus landers and balloons were successful, and the Halley flyby missions were largely successful, though the imaging quality at the comet was fairly miserable (it did provide essential pathfinding targeting for Giotto).

The series-4 missions (2 Phobos missions and poor Mars 96, which was launched-to-death) failed, but the Phobos 2 mission was a substantial scientific success as a Mars orbiter before it failed during the Phobos orbit rendezvous operations.  Then their budget failed.
*

It is evident that the Soviet space's technology seems to be better suited for hot environment such as for Venus than for the cold environment ones of Mars. I seems funny that Soviet's technology is better suited for hot environment and its technology was so heavy that landing to Mars makes a lot more trouble than to Venus.

I seems that the more Soviet has tried, the Venus case with 18 missions (approximately) smile.gif versus 8 missions to Mars (approximately). Long learning curve due to the Soviet leaders' pressure to accelerate the mission.

To land on Venus is easier than to Mars? Then to land on Phobos must be much easier than to Mars. As I was the witness of Hayabusa, the landing on Phobos needs a spaceship that travels very slow toward Phobos, slower than to Mars. The other obstacle, the Phobos shape is not symetrical and I am not sure if it rotates (slow or fast) or not. If it rotates, it would be even more difficult to land.

Rodolfo
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tedstryk
post Dec 16 2005, 07:30 PM
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"To land on Venus is easier than to Mars? Then to land on Phobos must be much easier than to Mars. "

Phobos is a whole other game...Venus is easier to land on than Mars in that you can exclusively use the atmosphere to break to a speed in which it is safe to land. That statement does not indicate that Venus is an easier place for a craft to operate - it is just the plunking it down that is simplified.


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edstrick
post Dec 17 2005, 05:58 AM
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Landing on Venus is "easy"... The US did it on the Zeroth try. Pioneer Venus multiprobe missions ended at impact. The large probe and one small probe went silent at impact, one small probe lasted about a second, and the third lasted some ?67? minutes before it FRIED. The small probes didn't drop their heat shields so their bottoms were kinda "armored".

The reason Mars is HARD to land on is the atmosphere. On the Moon, or Mercury (ignoring the large Delta-V velocity change to get there) all you need is throttlable rocket engines, doppler sensing radars to measure vertical and horizontal velocity and altitude, a not very smart computer, and landing legs. Terminal guidance helps in rough terrain.

On Venus, all you need is an atmosphere entry heat shield, and a parachute. If you want to still be transmitting when you land, a pressure-vessle and lots of insulation are recommended.

On Mars, you need everything you need at Venus to do atmosphere entry, and a double parachute system, supersonic drogue chute followed by a LARGE, probably supersonic main chute. That keeps you from making a small crater lined with shiny metal bits before you're well below the speed of sound.

But then, you have to switch over to an entirely separate, second landing system. Either you need a hard landing system like Pathfinder/MER, comparable to the Luna 9 and 13 systems on the Moon, or a Viking/MPL/Phoenix rocket-propulsion landing system comparable to Surveyor/Apollo/Luna-16-sample-return/Luna-17-Lunokhod. You can get by with dinky rockets or dinky fuel tanks at least, cause you are going hundreds of miles/hr when you light the engines, instead of thousands, but it's just as complicated as if there was no atmosphere.

To land on Mars is essentially twice as complicated as landing on Moon or Venus. It could be worse. Try landing on the top of Olympus Mons. You don't have time to deploy a chute. You'd have to do an atmosphere entry, slow down to something like Mach 2, and blow out plugs in the heat shield as you light engines, maybe while blowing off the backshield. Build the lander directly into the heatshield. Instead of 6 minutes of terror, you'd basically have 4. Yow!
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