MSL's Power Source |
MSL's Power Source |
Guest_exobioquest_* |
Nov 27 2005, 04:46 PM
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#1
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Guests |
Hi, new here.
I'm wondering if any news has come down about finalizing what MSL will run on? Will it be 2 Boeing's MMRTG (at ~100 watts?) or Lockheed Martin’s SRG (again ~100watts?), have they decided yet? Willl MSL use the RPS to trickle charge a battery or will MSL run on the RPS only? God I hope solar is not a option is anyone pushing for it? |
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Nov 29 2005, 04:04 PM
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#2
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Member Group: Members Posts: 350 Joined: 20-June 04 From: Portland, Oregon, U.S.A. Member No.: 86 |
Gasoline production is a front so the military can fuel their killing machines.
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Guest_exobioquest_* |
Nov 29 2005, 06:49 PM
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#3
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mcaplinger,
Its unlikely the mass of the SRG will be more then the MMRTG, the mass estimates are ranged now so it is possible the MMRTG will weigh less, but so far SRG usually has a range average a few kg below the MMRTG. Also your not considering all the extra weight of the radiators needed for the cruise staged to keep the MMRTG cool. Pu238 last cost ~$1400 per gram, so for the purchasing of the fuel alone (not counting the making of the GPHS) the MMRTG's fuel will cost 5.6 million while the SRG's will cost 1.4 million. Can anyone find out how much a GPHS cost to make? So just fuel cost the SRG is 4.2 million cheaper, not much but when the mission goes over budget every dollar less overbudget it goes the less likely the mission will get bumped up. mchan, those nuts and their logic its scares me so, how likely you think they will make a effective stink? |
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Nov 29 2005, 07:15 PM
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#4
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Senior Member Group: Members Posts: 2542 Joined: 13-September 05 Member No.: 497 |
QUOTE (exobioquest @ Nov 29 2005, 10:49 AM) Its unlikely the mass of the SRG will be more then the MMRTG, the mass estimates are ranged now so it is possible the MMRTG will weigh less, but so far SRG usually has a range average a few kg below the MMRTG. Also your not considering all the extra weight of the radiators needed for the cruise staged to keep the MMRTG cool. You make a fair point about the radiators, though even MPF and MER had radiator systems. I can't assess the mass estimates of the RTG systems themselves without detailed technical descriptions. However, from http://solarsystem.nasa.gov/scitech/display.cfm?ST_ID=705 "Initially, the MMRTG could have an advantage from a mass perspective, as current NASA/DOE guidelines recommend that early missions using SRGs carry at least one redundant SRG unit until its reliability has been verified [11]. This means that early missions using SRGs would need to carry a minimum of two SRG units. Thus, for early missions (where a redundant SRG would be required), the MMRTG (at <45 kg [10]) would be the lighter option for spacecraft requiring one or two RPS units." And according to the NASA FY06 budget request ( http://www.nasa.gov/pdf/107489main_FY06_1_sae.pdf ), page 2-22 "MSL - Department of Energy for Multi Mission Radioisotope Thermoelectric Generators" and page 2-14 "Radioisotope Power System (RPS): Deleted Small RPS or second generation Sterling (SRG), and RPS Power Conversion Technology (RPCT)." I think it's clear from that that MSL is planning to use the MMRTG. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Guest_exobioquest_* |
Nov 29 2005, 07:38 PM
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#5
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Guests |
mcaplinger,
The SRG has 2 55w sterling engines so when they say an extra do that mean 3 55w engines? That could not allow for easy counter piston action and cause much vibration. Maybe they mean 2 SRGs total, which would be 200w of power! That would be Fing wonderful from a mission perspective, all that extra power! That would still be 1/2 the fuel and 1/2 the heat output of the MMRTG, but the weight on the rover its self would definitely be an extra 25-40kg. I think they were talking about the second generation SRG: the ~350 watt version that was under development or something. |
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Nov 29 2005, 08:24 PM
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#6
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Senior Member Group: Members Posts: 2542 Joined: 13-September 05 Member No.: 497 |
QUOTE (exobioquest @ Nov 29 2005, 11:38 AM) The full document makes it pretty clear that yes, they mean two entire separate SRGs if you need the power from one. If you were an advocate of the SRG you might say that was an unfair imposition, but them's the rules at the moment. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Nov 29 2005, 08:41 PM
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#7
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Dublin Correspondent Group: Admin Posts: 1799 Joined: 28-March 05 From: Celbridge, Ireland Member No.: 220 |
QUOTE (mcaplinger @ Nov 29 2005, 09:24 PM) If you were an advocate of the SRG you might say that was an unfair imposition, but them's the rules at the moment. Well if I was paying hundreds of millions for a mission then I'd say that them would be reasonable rules, much as I like the SRG concept it needs to be flight proven before it's used for something as important as this. |
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Guest_exobioquest_* |
Nov 29 2005, 08:57 PM
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#8
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I would be estactic if anything that can provide 200w (4800wh) of continues power was going on the MSL, be it a MMRTG or SRG. With 2 SRG weight is the only major problem, you still have less thermal and fuel needs then the MMRTG. weight over the whole spaceship could be negated with the reduction to the thermal control system and also is the cruise stage going to need solar panals?, maybe at 100w but most likely not with 200w, that some possible weight savings. At 200w (and considering the SRGs lasts a long as claimed) MSL would most likely last for a decade or more! At 200w (and not adding lighting for night time driving) MSL could do over a km a day of driving! It could do hundreds of km over its mission! Just the idea makes me drool!
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