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Guest_Zvezdichko_* |
Jun 24 2008, 09:27 AM
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#136
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They're referring to MetNet, actually.
http://www.unmannedspaceflight.com/index.php?showtopic=3896 - here's a thread I wrote about it. |
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Jun 24 2008, 12:44 PM
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#137
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
Good, maybe they thought better of sticking MetNet on a Volna.
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Guest_Zvezdichko_* |
Jun 24 2008, 01:09 PM
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#138
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Looks like they really want to send a Mars lander. This makes the 2009 Mars missions worrisome - all Mars landings will include yet untested technologies.
As for MetNet, it seems they will enter the amosphere in a ballistic trajectory. After that... I don't know. These landers even don't have parachutes. |
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Jun 24 2008, 01:16 PM
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#139
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
Looks like they really want to send a Mars lander. This makes the 2009 Mars missions worrisome - all Mars landings will include yet untested technologies. As for MetNet, it seems they will enter the amosphere in a ballistic trajectory. After that... I don't know. These landers even don't have parachutes. They did drop tests this spring and it went flawlessly. That is probably why they wanted to go ahead and send it. Of course, this little lander/penetrator is only a test for the MetNet mission, so it, in a sense, is the proving mission. -------------------- |
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Guest_Zvezdichko_* |
Jun 24 2008, 01:23 PM
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#140
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In my opinion drop tests are not of much value. For example, the parachute and the airbags of Beagle 2 were successfully tested (though it's a controversial subject). The systems of Deep Space 2 were also tested very successfully (I have watched a whole documentary about the tests of these penetrators). But Mars is different than the Earth. We have a thinner atmosphere, fluctuations may fool the onboard computer...
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Jun 24 2008, 01:42 PM
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#141
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
In my opinion drop tests are not of much value. For example, the parachute and the airbags of Beagle 2 were successfully tested (though it's a controversial subject). The systems of Deep Space 2 were also tested very successfully (I have watched a whole documentary about the tests of these penetrators). But Mars is different than the Earth. We have a thinner atmosphere, fluctuations may fool the onboard computer... Well, like you said earlier, MetNet doesn't have a parachute, and it doesn't have much else to do on the way down, so a computer problem is less likely. The main purpose of the drop tests is to make sure it still worked after a hard hit. Mars does have a thinner atmosphere and different conditions, which is the whole reason for the precursor mission - send one and see if it works under real conditions before they send a whole network of MetNet landers. In a sense, this precursor is an in situ test, but one that might yield a little science if it works. I do wish they had gone with the original plan to send two or three landers. I would hate to think that they had a perfectly good lander that was unlucky and hit a sharp rock (the Russians should know not to test their Mars luck, because they don't have any). -------------------- |
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Guest_Zvezdichko_* |
Jun 24 2008, 01:55 PM
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#142
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the Russians should know not to test their Mars luck, because they don't have any.
This is the best I read in your post To be honest, I'm worried because I see they still work somehow in... a Soviet manner (can't find a better word) - I mean - they insist to launch the mission in 2009 at any cost, for example. Well, sometimes it's good, because I hate delays. However, if Mars' 73 had been delayed to 1975, they would have been the first on the planet. Hope you understood me. |
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Jun 24 2008, 03:12 PM
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#143
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
You know, NASA and the Russians have the opposite problem. NASA will often scrimp on instruments, sending probes without many instruments (DAWN with no magnetometer, the MERs). The good side is that such spacecraft are reliable, the bad side is that there are measurements that scientists really wanted that they can't take. The Russians, on the other hand, seem to try to strap every last thing they can to the mission. I wish they would just launch an orbiter (maybe the much-needed SAR orbiter that never seems to make the cut) with maybe a penetrator or two. But having sent 10 Mars missions (I know there were more, but I am ignoring launch failures, since those failures have nothing to do with the complexity of the actual spacecraft) and not having one full success, one would think that they wouldn't try to jump straight in with an orbiter-drop-off Chinese orbiter-lander-Phobos landing and ascent-Phobos sample-return mission (Of the often-cited "successes," The Mars-2 orbiter was in the right orbit but couldn't sent telemetry, Mars-3 could send limited telemetry (not for long enough to send pictures at resolution better than 250-line mode) and was in an orbit that only took it near the planet every 18 days, Mars-5 failed after only 9 days with many of its science goals unfinished and with 75 percent of its film unexposed).
Of course, it has been in the pipeline for a while, and since it is the only mission (along with MetNet) that has enjoyed any serious backing until very recently, it is understandable that there are a lot of goals for it. Incidentally, a lot of the hardware is leftover from Phobos '89, so at its core, this may be the last Soviet mission. -------------------- |
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Guest_Zvezdichko_* |
Jun 24 2008, 03:25 PM
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#144
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But if we look at the subject with optimism, we have an example how a complex mission may be near to success. For example, Hayabusa - it landed twice, took off, there were engine problems + MINERVA failed to achieve a soft landing. Phobos-Grunt may be more successful than Phobos 2 (which indeed sent some data, including images).
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Jun 24 2008, 03:40 PM
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#145
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Member Group: Members Posts: 220 Joined: 13-October 05 Member No.: 528 |
I think reffering to it as "working in a Soviet manner" is a good way to put it. It often seemed that the US would achieve something in their space program that the Russians had not done, then the Russian responce was to point at something else. So, the Russians fail to make any manned lunar flights, declare that orbital stations (aka Salyut) are the true destiny of manned spaceflight, and in the meantime "did we mention our vigorous unmmanned mars exploration efforts? Heck, you Americans are only sending an orbiter (Mariner 8,9) but we are sending orbiters AND landers (Mars 2,3). " So, not only point in a different direction, but stack multiple firsts into a single mission. They would also load down a mission with lots of elements, to try to make up for a previous failure. So the Phobos missions were a failure, but the next mission includes multiple elements designed to impress everyone with the scope of the mission, and Mars 96 is born. Phobos Grunt seems to be carrying on that tradition very well. No unmanned Mars shots in 13 years, and the last even partially sucessful mission was 20 years ago. That partially sucessful mission was merely to rendesvous and drop a payload onto Phobos. Well, well, we are going to do better than that on this second try, and return a sample to Earth. Oh, and take along a Chinese satellite. Oh, hey, and take along a Mars lander. ..... We thought about taking a tourist, but decided to leave that for the next mission. |
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Jun 24 2008, 08:30 PM
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#146
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
Another thing that makes me optimistic is that the weakest link in the Soviet program was a result of bad computers, something that will likely no longer be an issue.
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Jun 25 2008, 07:19 AM
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#147
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Member Group: Members Posts: 118 Joined: 18-November 07 Member No.: 3964 |
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Guest_Zvezdichko_* |
Jun 25 2008, 11:04 AM
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#148
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I liked to see they chose Zenith, because in my opinion Proton is very unreliable.
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Jun 25 2008, 11:13 AM
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#149
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Junior Member Group: Members Posts: 66 Joined: 8-November 05 From: Australia Member No.: 547 |
Another thing that makes me optimistic is that the weakest link in the Soviet program was a result of bad computers, something that will likely no longer be an issue. I think Ted has hit the nail on the head here. Computer hardware failure (and software upload control protocols) had doomed every Soviet Mars probe since the Mars 4/5/6/7 flotilla (and maybe caused the Mars 3 orbiter to drop the datalink from its lander thus lose the 1st pics from the Martian surface...) Lets hope that this time around some bright-spark of an electronics factory manager doesnt have a brilliant cost-cutting idea like using aluminium instead of gold in IC fabrication... (shakes head, sobs quietly) |
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Jun 25 2008, 11:25 AM
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#150
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Founder Group: Chairman Posts: 14432 Joined: 8-February 04 Member No.: 1 |
I liked to see they chose Zenith, because in my opinion Proton is very unreliable. http://www.geocities.com/launchreport/reliability2008.txt If you take all Zenit variations and all Proton variations - the Zenit comes out at 81.5% success rate, the Proton 92.3% In the last 12 months, Zenit has 4 launches with one failure, Proton 3 launches with one failure. http://www.geocities.com/launchreport/stats2008.txt The Proton is not unreliable, especially when compared to Zenit. Doug |
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