Author Topic: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011  (Read 412706 times)

Offline Danderman

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #740 on: 11/11/2011 01:08 PM »
My 2 cents worth:

Since the basic Fregat stage does not have uplink capability, the designers seem to have implemented an uplink channel via the payload (where commands are relayed to the Fregat/MDU via hard wires from the payload). Unfortunately, the payload was not designed for functionality in LEO, so that commands radioed from the ground may be blocked by the Fregat stage; alternatively, the payload may be a "safe" mode, unable to communicate.

The better design approach would have been to implement a separate uplink channel on the Fregat/MDU itself, which would also be useful for LEO missions. Without this separate uplink channel, the mission was effectively killed when the Fregat/MDU failed to make its first burn.

Offline HIPAR

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #741 on: 11/11/2011 01:28 PM »
My 2 cents worth:

...

The better design approach would have been to implement a separate uplink channel on the Fregat/MDU itself, which would also be useful for LEO missions. Without this separate uplink channel, the mission was effectively killed when the Fregat/MDU failed to make its first burn.

I wouldn't have been surprised if the mission had failed landing on Phobos or during the attempt to return the soil sample.  But after 60 years of advanced rocket science, how does one get stuck in low earth orbit?

So I'd suppose rocket science will remain just that for the foreseeable future.

---  CHAS

Online ugordan

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #742 on: 11/11/2011 01:32 PM »
But after 60 years of advanced rocket science, how does one get stuck in low earth orbit?

I imagine you do it in a similar manner to the CONTOUR spacecraft, which managed to blow itself apart while trying to leave Earth orbit.

Offline orbitaldebris

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #743 on: 11/11/2011 01:37 PM »
But after 60 years of advanced rocket science, how does one get stuck in low earth orbit?

I imagine you do it in a similar manner to the CONTOUR spacecraft, which managed to blow itself apart while trying to leave Earth orbit.
But the remaining pieces DID leave earth orbit. :)

Online MarekCyzio

So do all Phobos fuel tanks have heaters to keep fuel liquid?

Offline Robotbeat

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #745 on: 11/11/2011 01:46 PM »
Poppycock.

Nobody died.

Try to keep things in perspective.

Nobody died due to the financial crisis either. Do people always have to die for something to be a disaster?

You're right. Please feel free to panic and scream in fright.
Seriously, let's man-up a little.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline input~2

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #746 on: 11/11/2011 01:47 PM »
Ted Molczan conjecture on Ph-G recent mean motion slight decrease
http://satobs.org/seesat/Nov-2011/0110.html

Online kevin-rf

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #747 on: 11/11/2011 01:54 PM »
Ted Molczan conjecture on Ph-G recent mean motion slight decrease
http://satobs.org/seesat/Nov-2011/0110.html
Interesting, he mentioned reading NSF for updates in the post. I am sure Chris is now blushing ;)
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Offline LEGO Space

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #748 on: 11/11/2011 01:56 PM »
Is it realistic to hope for the construction of a Phobos-Grunt 2 with patches to the known PG 1 bugs? Given that the entire Phobos-Grunt project cost 120 million $ so far, how high would you estmate the additional costs to be?
« Last Edit: 11/11/2011 01:58 PM by LEGO Space »

Offline mr. mark

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #749 on: 11/11/2011 01:58 PM »
Reflecting on things, this is going to look even worse if the Mars Curiosity launch gets off to a good start. It's damaging to the image of the Russian scientific community. Maybe some heads do need to roll, so to speak, to get things moving in the right direction again. But, all programs suffer losses. If this is a loss, let's hope that it's a blip on the road to a successful unmanned program.   

Offline avitek

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #750 on: 11/11/2011 02:02 PM »
I saw elsewhere a chart of departure velocities vs. launch date and Mars arrival date for 2011 launch window, but I am unable to find it now. Pls. help me with URL.

Online ugordan

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #751 on: 11/11/2011 02:08 PM »
Ted Molczan conjecture on Ph-G recent mean motion slight decrease
http://satobs.org/seesat/Nov-2011/0110.html

I'm wondering if residuals of 3-axis control thruster firings are sufficient to account for this modest altitude increase or if we're talking about a propellant leak.

Online Galactic Penguin SST

One semi-crazy idea that's being discussed by posters at the NK forum is that given the burn sequence should be triggered by energy-independent onboard clock device which was set to work in Moscow Standard Time (like all Russian spacecrafts), the time mark might come one hour late because the clock moved itself off the daylight saving hour, while it shouldn't have. If an industry standard imported RTC chip were used, this scenario may not be out of question...

This is the first year which Russia abandons DST transitions and Moscow stays permanently in UTC+4...

P.S. If this is the problem that doomed Phobos-Grunt, it wouldn't be the first time unit conversions doomed a Mars mission...
Chinese spaceflight is a cosmic riddle wrapped in a galactic mystery inside an orbital enigma... - (not) Winston Churchill

Online Galactic Penguin SST

Oh and BTW, it looks like the ground stations at Baikonur did not have the ability to send commands to Phobos-Grunt via X-band...  :o

Quote
I'm disappointed after I'm said today that the only Kub-Kontur station at Baikonur that could transmit commands to Phobos-Grunt, had been pillaged as early as in 2007. I also held a hope for IP-5 "Saturn" which they promised to outfit with Spektr-X device, but they are saying it can only serve as downlink.
It turns out, Baikonur is really unable to send any commands to the probe, and only can sweep the sky with "Daisy" antenna at IP-1.
« Last Edit: 11/11/2011 02:20 PM by Galactic Penguin SST »
Chinese spaceflight is a cosmic riddle wrapped in a galactic mystery inside an orbital enigma... - (not) Winston Churchill

Offline input~2

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #754 on: 11/11/2011 02:27 PM »
Ted Molczan conjecture on Ph-G recent mean motion slight decrease
http://satobs.org/seesat/Nov-2011/0110.html

I'm wondering if residuals of 3-axis control thruster firings are sufficient to account for this modest altitude increase or if we're talking about a propellant leak.
The altitude was slightly decreasing (mean motion increasing) until November 10 between 1831UTC and 2301UTC, it then started to slightly increase (mean motion decreasing). So, a propellant leak seems more likely.
« Last Edit: 11/11/2011 02:36 PM by input~2 »

Offline ChileVerde

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #755 on: 11/11/2011 02:27 PM »

btw. How mush Cesium was on this probe, and is packaged such that it will survive (not disperse) reentry? Are we talking the equiv. of a smoke detector, or something more sinister?

Looking around, the MIMOS II Mossbauer spectrometer appears to have 300 ci of Co-57, which, if I've got the right specific activity, corresponds to 0.037 micrograms of Co-57, or a cube 0.016 mm on a side.  I don't think we're talking about a major radiological catastrophe here.
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Offline iamlucky13

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #756 on: 11/11/2011 03:19 PM »

Quote
. Even if by the time they sort things it's too far out of plane or too low to make a proper trans-Mars injection, it would still be a functional spacecraft ....alternate mission like visiting a near earth asteroid.
if you believe in stuff like this I have a bridge I could sell you ...  ::)

I readily point out my post reflected the extreme end of optimism, but if you want to mock me, at least explain why, if they are perhaps able to recover the spacecraft but not in time to reach Mars it wouldn't be possible to even consider other missions.


btw. How mush Cesium was on this probe, and is packaged such that it will survive (not disperse) reentry? Are we talking the equiv. of a smoke detector, or something more sinister?

Looking around, the MIMOS II Mossbauer spectrometer appears to have 300 ci of Co-57, which, if I've got the right specific activity, corresponds to 0.037 micrograms of Co-57, or a cube 0.016 mm on a side.  I don't think we're talking about a major radiological catastrophe here.

MSL carries somewhere on the order of 50,000 Ci (170 million times that much)

A smoke detector holds about 1 uCi. You can also buy calibration sources of about that amount over the internet with nothing more than a credit card.

Offline Antares

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #757 on: 11/11/2011 03:20 PM »
But after 60 years of advanced rocket science, how does one get stuck in low earth orbit?

Because rockets are still built by humans.
If I like something on NSF, it's probably because I know it to be accurate.  Every once in a while, it's just something I agree with.  Facts generally receive the former.

Offline jongoff

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #758 on: 11/11/2011 03:24 PM »
But after 60 years of advanced rocket science, how does one get stuck in low earth orbit?

Because rockets are still built by humans.

Well, they're built by humans, launched, and then you have no way to fix them after they leave the ground.  It's the whole "this system has to work flawlessly the first time with no hope of mechanical repair and only slight hope of programming repair, oh and it was made by humans" thing that hurts.

~Jon

Offline Robotbeat

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #759 on: 11/11/2011 03:28 PM »
But after 60 years of advanced rocket science, how does one get stuck in low earth orbit?

Because rockets are still built by humans.

Well, they're built by humans, launched, and then you have no way to fix them after they leave the ground.  It's the whole "this system has to work flawlessly the first time with no hope of mechanical repair and only slight hope of programming repair, oh and it was made by humans" thing that hurts.

~Jon
I understand there's really no way this would ever happen in today's environment (fiscal, safety, technology, etc), but out of curiosity, what is the delta-v between this probe and ISS? They are, after all, in pretty close to the same inclination and both in LEO (though different altitudes).
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