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#420
by
anonymous1138
on 06 Aug, 2012 06:30
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1.4 kg of fuel left onboard
I heard it as 140.6 kg
It was 1.4Kg, can't be 140Kg- too much.
Jim
Yeah, I figured that number was too high. They must have mis-reported it.
I'm sure I heard 140.6kg. Remember the descent stage started out with 390kg propellant aboard so seems a good number to me, given a smooth descent without complications.
You did hear 140.6, as I did. That's right.
There is a margin, but I didn't think it was that big.
There's an update to this paper (this one is 2006), but I can't find it at the moment:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090007730_2009006430.pdf
Page 13 says the +/- 3 sigma fuel consumption should be between 284.2 kg and 312.8 kg. That should have left 77.2 kg to 105.8 kg to spare.
I updated my comment from earlier - probably not a good idea in a fast moving live thread.:
Going from memory, 4 thrusters at 800 lbs each (3200 lbs) and hydrazine Isp at ~230 gives about 14 lbs/sec (6.4 Kg/sec). So, they had about ten seconds of propellant left. Seems about right. Certainly NOT 1.4 kg.
Not sure on these numbers, but think they are close.
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#421
by
robertross
on 06 Aug, 2012 06:30
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#422
by
Kaputnik
on 06 Aug, 2012 06:30
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Where's Bolden boogying off to?
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#423
by
Robotbeat
on 06 Aug, 2012 06:31
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140kg prop remaining... So they could've landed another 100kg, right?
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#424
by
Lars_J
on 06 Aug, 2012 06:31
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Pure chaos at the moment.
Most seem to have forgotten that this is a press conference...
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#425
by
robertross
on 06 Aug, 2012 06:31
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This place is going crazy!!
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#426
by
Robotbeat
on 06 Aug, 2012 06:32
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Were there this many hi-fives for MER? Are high-fives kind of more trendy now?
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#427
by
Stardust9906
on 06 Aug, 2012 06:32
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#428
by
93143
on 06 Aug, 2012 06:32
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140kg prop remaining... So they could've landed another 100kg, right?
Wasn't that before flyaway?
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#429
by
simonbp
on 06 Aug, 2012 06:33
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Were there this many hi-fives for MER? Are high-fives kind of more trendy now?
The EDL team is much larger this time...
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#430
by
Jason1701
on 06 Aug, 2012 06:33
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140kg prop remaining... So they could've landed another 100kg, right?
Wasn't that before flyaway?
Correct.
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#431
by
Moskit
on 06 Aug, 2012 06:33
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Russian rad detector, Spanish weather sensors.
Polish uncooled infrared detectors.
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#432
by
robertross
on 06 Aug, 2012 06:33
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Were there this many hi-fives for MER? Are high-fives kind of more trendy now?
Oh let them have their moment in the spotlight...
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#433
by
Archibald
on 06 Aug, 2012 06:34
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HOLY ----
Touchdown confirmed!
Wooooohooooooooooooooo !!!! Can't believe it. It boggles the mind. Now, go for exploration, were no MER has gone before.
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#434
by
FinalFrontier
on 06 Aug, 2012 06:34
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I still cannot believe it worked, flawlessly to boot.
It looks like they can't either.
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#435
by
Robotbeat
on 06 Aug, 2012 06:34
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140kg prop remaining... So they could've landed another 100kg, right?
Wasn't that before flyaway?
It was kind of a joke. But it does kind of mean this Skycrane system (blah, maneuver, blah) should be capable of an even 1 ton.
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#436
by
robertross
on 06 Aug, 2012 06:36
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The team brough us victory today (like the Olympics)
Great inspiration for young people
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#437
by
robertross
on 06 Aug, 2012 06:37
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"What a deal. This movie cost less than $7 per American citizen"
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#438
by
alexw
on 06 Aug, 2012 06:38
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There is a margin, but I didn't think it was that big.
There's an update to this paper (this one is 2006), but I can't find it at the moment:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090007730_2009006430.pdf
Page 13 says the +/- 3 sigma fuel consumption should be between 284.2 kg and 312.8 kg. That should have left 77.2 kg to 105.8 kg to spare.
Going from memory, 4 thrusters at 800 lbs each (3200 lbs) and hydrazine Isp at ~230 gives about 14 lbs/sec (6.4 Kg/sec). So, they had about ten seconds of propellant left. Seems about right. Certainly NOT 1.4 kg.
Not sure on these numbers, but think they are close.
That's rather more thrust than the weight, no? Something like 3000 pounds-mass, but at only 40% of Earth gravity. Fuel consumption is presumably throttled back.
-Alex
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#439
by
ginahoy
on 06 Aug, 2012 06:38
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Most seem to have forgotten that this is a press conference...