posted 11-04-2011 05:18 AM               

This thread is intended for comments and questions regarding the Phobos-Grunt mission and the updates published under the topic: Russia's Phobos-Grunt mission to Mars' moon.

Phobos-Grunt is Russian sample return mission to Phobos, one of the moons of Mars. The Chinese Mars orbiter Yinghuo-1 will be sent together with the mission, as will the Living Interplanetary Flight Experiment funded by the Planetary Society.

Phobos-Grunt is to become the first Russian interplanetary mission since the failed Mars 96 mission. If successful it will be the first spacecraft to return a macroscopic extraterrestrial sample from a planetary body since Luna 24 in 1976.

posted 11-04-2011 05:19 AM               

Deputies asked whether it was too risky to send a hitherto untested rover on such a responsible mission and whether it would be more reasonable to delay the mission until the end of the tests.

posted 11-08-2011 12:11 PM               

quote:

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Originally posted by Lasv3:
No moving wheeled vehicle - at least that's what I understand "rover" means. A little bit confusing...

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posted 11-09-2011 05:51 PM               

"It sounds like the spacecraft has gone into a safe mode," commented British propulsion expert Alan Lawrie from Astrium UK.

"These spacecraft do that if they hit these types of problems. It's a mode whereby the spacecraft knows it cannot do itself any harm, and that gives controllers on the ground the time to get the spacecraft back into the right configuration and to do the correct manoeuvres."

posted 12-09-2011 10:56 AM               

Last night managed to turn the vehicle into a convenience store's parking lot in time to jump out and view a pass of Phobos-Grunt. It was rising brightly in the west as it passed through the Summer Triangle between Albireo and Altair.

posted 12-11-2011 01:24 PM               

Final tests uncover serious problems

On November 1, inside the MIK-31-40 assembly building, joint industrial teams had conducted tests of opening of the probe's solar panels, Roskosmos said, without much details. However only after the launch of the ill-fated mission, not unexpected stories started surfacing about numerous problems which had been uncovered during final tests in Baikonur.

As it transpired, engineers found that the polarity for the steering control of the main engine had been mistakenly switched over in the flight control software of the main BKU computer. Nobody knew how such a major problem could've been missed during supposedly thorough certification tests in Moscow. Initially, managers decided to limit corrective actions to re-soldering of respective cables. As a result, six cables had to be reconnected on a spacecraft fully loaded with toxic and explosive propellants. Similar attempts to do electric repairs on the fueled vehicle led to the mass loss of life in Baikonur in the aftermath of the infamous Nedelin disaster in 1960.

However, after these repairs, it had become clear that all control signals from multiple cables had been channeled to the same driving mechanism. This mistake could not be fixed by re-routing cables, instead requiring complex changes in the flight control software. Last updates to the programming software had to be added right at the launch site, leaving no time for a new round of tests. The incident was reported to the head of the Russian space agency, Vladimir Popovkin.

posted 01-11-2012 01:00 PM               

Looks like the USA and Canada are well positioned to be under the ascending (moving south to north) revs prior to, and descending revs following, the predicted time. Europe is well placed only for descending revs prior to. Could put on quite a show for observers in those locations, if things work out well.

posted 01-16-2012 11:39 PM               

A powerful electromagnetic emission from a U.S. radar in the Pacific could have caused the malfunctioning of the Russian Phobos-Grunt probe, the Kommersant daily said on Tuesday.

A Russian government investigation commission is considering several causes of the failure, including a short circuit or "external impact," the paper said citing an unnamed source in the Russian space industry.

"Experts do not dismiss the possibility that the probe could have accidentally come under the impact of emissions [from a U.S. radar stationed on the Marshall Islands], whose megawatt impulse triggered the malfunctioning of on-board electronics," the source said.

posted 01-18-2012 01:43 PM               

"Consider the power of the impact. I don't think the Americans have radars capable of ensuring such power at such an altitude [about 200 kilometers]," said Alexander Zakharov of the Russian Academy of Sciences Space Research Institute, where the Phobos equipment and research program were developed.

He suggested the theory was just a blind to cover up some people's mistakes.

"I simply think that is disingenuous. It is convenient to find the cause of the failure on the outside," he said, adding that "external impact hypotheses" were "far-fetched."

"The spacecraft itself should be examined first. There are problems there," he said.

The most likely culprit in the failure of the probe's propulsion unit to ignite soon after it had entered orbit on November 9 was a programming error in the flight control system. Post-failure tests (apparently simulating in-flight conditions) revealed that in 90 percent of cases, the processor of the main flight control computer onboard the spacecraft would be overloaded. It could easily lead to crashes and rebooting as more systems were being activated after the spacecraft had left the range of Russian ground control stations after reaching orbit. Among those systems were star trackers (used for attitude control in the shadow of the Earth) and a Chinese satellite. In the meantime, the power supply system onboard the spacecraft worked flawlessly.

Following the initial failure, as ground controllers apparently succeeded in activating the X-band transmitter onboard the spacecraft, new problems arose. The device would transmit a signal with a power of around 40 watts, however its own operation would consume around 200 watts. The deactivation of the transmitter was not taking place when the spacecraft was flying in the shadow of the Earth for prolonged periods of time. As a result, the probe slowly drained its recharable power batteries and then its emergency power source KhIT, leading to a complete deactivation of onboard systems on November 28, 2011.

posted 02-23-2012 12:10 PM               

Poor device selection/specification, last-minute hardware modifications, and on-pad software patches all paint a rather complex but troubling picture of program management.