IPB

Welcome Guest ( Log In | Register )

MSL's Power Source
Guest_exobioquest_*
post Nov 27 2005, 04:46 PM
Post #1





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 Martinís 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?
Go to the top of the page
 
+Quote Post
 
Start new topic
Replies
mike
post Nov 29 2005, 04:04 PM
Post #2


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.
Go to the top of the page
 
+Quote Post
Guest_exobioquest_*
post Nov 29 2005, 06:49 PM
Post #3





Guests






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?
Go to the top of the page
 
+Quote Post
mcaplinger
post Nov 29 2005, 07:15 PM
Post #4


Senior Member
****

Group: Members
Posts: 1293
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.
Go to the top of the page
 
+Quote Post
Guest_exobioquest_*
post Nov 29 2005, 07:38 PM
Post #5





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.
Go to the top of the page
 
+Quote Post
mcaplinger
post Nov 29 2005, 08:24 PM
Post #6


Senior Member
****

Group: Members
Posts: 1293
Joined: 13-September 05
Member No.: 497



QUOTE (exobioquest @ Nov 29 2005, 11:38 AM)
Maybe they mean 2 SRGs total, which would be 200w of power!
*


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.
Go to the top of the page
 
+Quote Post
helvick
post Nov 29 2005, 08:41 PM
Post #7


Dublin Correspondent
****

Group: Admin
Posts: 1797
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.
Go to the top of the page
 
+Quote Post
Guest_exobioquest_*
post Nov 29 2005, 08:57 PM
Post #8





Guests






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!
Go to the top of the page
 
+Quote Post
mcaplinger
post Nov 29 2005, 10:00 PM
Post #9


Senior Member
****

Group: Members
Posts: 1293
Joined: 13-September 05
Member No.: 497



QUOTE (exobioquest @ Nov 29 2005, 12:57 PM)
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!
*


Even if any of these things were true (they're not, as far as I know -- there's nothing terribly enabling about going to twice the RTG power. You still need batteries, you still don't have enough power for active thermal control of all elements so you have thermal cycling wearout, you still have mechanical wearout problems, and there is no way that MSL is ever going to drive 1 km/day under any circumstances no matter how much power it has) MSL is using the MMRTG anyway. So your drool is wasted. smile.gif


--------------------
Disclaimer: This post is based on public information only. Any opinions are my own.
Go to the top of the page
 
+Quote Post
helvick
post Nov 29 2005, 10:30 PM
Post #10


Dublin Correspondent
****

Group: Admin
Posts: 1797
Joined: 28-March 05
From: Celbridge, Ireland
Member No.: 220



QUOTE (mcaplinger @ Nov 29 2005, 11:00 PM)
and there is no way that MSL is ever going to drive 1 km/day under any circumstances no matter how much power it has)  MSL is using the MMRTG anyway.
*

That's an important point. Raw speed isn't of much use, the objective is to try to find things and that requires that MSL looks very closely at the stuff around it, not just race along for the sake of it. There might be the odd dash or two that are marginally faster than the flat out rates we've seen from Opportunity and Spirit but I suspect it will spend a lot of time making about the same rate of progress that the MER's do. And there's nothing wrong with that.
Go to the top of the page
 
+Quote Post
Guest_exobioquest_*
post Nov 29 2005, 10:49 PM
Post #11





Guests






helvick,

Sure there is nothing wrong wit MER speeds, but MSL will have:

-10X the upload speed with MRO in orbit, Even without MTO, MRO is going to provide major communication bandwidth improvements.

-A much faster processor (RAD750?) so autonav would be faster and/or more advance, might be able to command MSL to go up to a rock sample it and then go up to another sample it and so forth by sending only one set of commands and the rover does all the rest autonomously.

-Onboard sample loader: if all the instruments (except the microcam) run of samples provided by the arm to a sample loader in the rovers body, then MSL could get a sample from one rock and move on to another while its analyzing the sample it drilled up: so MSL could sample several rocks in the time it takes MER to do one!

edit: spelling/grammer
Go to the top of the page
 
+Quote Post
helvick
post Nov 29 2005, 11:10 PM
Post #12


Dublin Correspondent
****

Group: Admin
Posts: 1797
Joined: 28-March 05
From: Celbridge, Ireland
Member No.: 220



QUOTE (exobioquest @ Nov 29 2005, 11:49 PM)
Sure there is nothing wrong wit MER speeds, but MSL will have..
*

All true and those will allow it to progress faster but it will also have good reason to carefully examine what it comes across more carefully than the MER's because it can.

I'm of the opinion that the biggest speed boost will actually come from the RAD 750. It has 10x the integer performance and about 20x the fp performance of the RAD6000's on the MER's. Combined with the increased on board storage that alone should allow MSL to do safely drive much faster.

I don't think it will though, the whole point is to gather data and study it. While I love the idea of whizzing around on the surface of Mars I really think they will be taking things very easy. At least until such time as they have hit all primary mission objectives.

Then again they might land it on Meridiani and find themselves a kilometer or two from somewhere really interesting. That might warrant a quick dash across the plains at the start but otherwise I'd say she'll be taking things slow and easy.
Go to the top of the page
 
+Quote Post
RNeuhaus
post Nov 30 2005, 03:34 AM
Post #13


Senior Member
****

Group: Members
Posts: 1636
Joined: 9-May 05
From: Lima, Peru
Member No.: 385



QUOTE (helvick @ Nov 29 2005, 06:10 PM)
I'm of the opinion that the biggest speed boost will actually come from the RAD 750. It has 10x the integer performance and about 20x the fp performance of the RAD6000's on the MER's. Combined with the increased on board storage that alone should allow MSL to do safely drive much faster.
*

I think that the CPU capacity of MER along with the low bandwidth communication was the hidering factors to slow the advance of the Mars mission. The CPU capacity is a very important thing for analyzing the land obstacles before steping an advance for every around 40 seconds and then take some 15 seconds in analyzing the same task and over.

About the bandwidth of the communication of MER is no more than 128 kbits/sec that is enough to send at least 80 pictures per day (between 1kBytes to 350 kBytes each one). The MSL will take the advantage of greater bandwidth transmission capacity of MRO that might send from Mars to Earth between 1 to 3 GBytes depending upon to the distance between the Earth and Mars.

The others things that I expect the the new MSL incorporates three new instruments after taking the advantage of greater power supply capacity. These new instruments requires very few watts and they might be activated whenever they are needed.

1) Microphone to listen the environment sounds. It would be a very interesting thing and it might be a very valuable device after the camera. This is a good thing to improve the PR. Many people would get exited to listen the sounds from the other words. Very few words can be listen except to Venus, Mars, Titan, and what else more?

2) Two extra arms at both sides as an useful support to help any situation such as to shove, drill, lift MSL from emergency, scratch, hammer, or anything else on the surface. I feel deseperated that MER has no arms to touch, push (from Purgatory Sand) and neither grasp any thing from the surface. It is like a more complete geologist with eyes (ok), ears (not yet), legs (ok), smell (ok -miniTES, x-ray, spectrometer, etc.) and arms (not yet)

3) Anenometer to measure the wind speed and direction in order to help to understand better the geology (the wind also plays an important rol as an aeolian erosion).

Rodolfo
Go to the top of the page
 
+Quote Post
Guest_exobioquest_*
post Jan 15 2006, 04:57 AM
Post #14





Guests






What is this:
"NASA is considering nuclear energy for powering the Mars Science Laboratory. The rover would carry a U.S. Department of Energy radioisotope power supply that would generate electricity from the heat of plutonium's radioactive decay. This type of power supply could give the mission an operating lifespan on Mars' surface of a full martian year (687 Earth days) or more and in extreme seasonal conditions such as those at high latitudes. NASA is also considering solar power alternatives that could meet the mission's science and mobility objectives." -- MSL Home Page

What, what, what! Solar is still a option can somebody clear this up? I thought things were a little more well defined on what the power supply was going to be.
Go to the top of the page
 
+Quote Post
mcaplinger
post Jan 15 2006, 06:12 AM
Post #15


Senior Member
****

Group: Members
Posts: 1293
Joined: 13-September 05
Member No.: 497



QUOTE (exobioquest @ Jan 14 2006, 08:57 PM)
Solar is still a option can somebody clear this up?
*


You'll also note that all the images of MSL on the website appear to have the power source "airbrushed out". As far as I can tell, this is NASA PIO's way of dealing with anti-nuke sentiment.

I haven't seen any indication that the MMRTG is not the power source. Solar would require a complete redesign of the system, if it was viable at all (certainly the MER experience is that you can go for a long time on solar, but I don't think one can count on random wind cleaning events for mission success.)


--------------------
Disclaimer: This post is based on public information only. Any opinions are my own.
Go to the top of the page
 
+Quote Post

Posts in this topic
- exobioquest   MSL's Power Source   Nov 27 2005, 04:46 PM
- - helvick   QUOTE (exobioquest @ Nov 27 2005, 05:46 PM)Go...   Nov 27 2005, 06:30 PM
|- - exobioquest   QUOTE (helvick @ Nov 27 2005, 12:30 PM)The ME...   Nov 27 2005, 06:53 PM
|- - helvick   QUOTE (exobioquest @ Nov 27 2005, 07:53 PM)Th...   Nov 27 2005, 08:05 PM
|- - exobioquest   Well maybe your right about anti-nuclear nuts, I h...   Nov 27 2005, 08:38 PM
|- - helvick   QUOTE (exobioquest @ Nov 27 2005, 09:38 PM)35...   Nov 27 2005, 09:45 PM
||- - exobioquest   From what I have read SRG has survived several yea...   Nov 27 2005, 10:18 PM
|- - mchan   QUOTE (exobioquest @ Nov 27 2005, 12:38 PM)We...   Nov 29 2005, 05:46 AM
- - DEChengst   I'm quite sure MSL would survive after the bat...   Nov 27 2005, 09:14 PM
|- - exobioquest   Ya, but I don't think 100watts is enough to do...   Nov 27 2005, 09:30 PM
- - mcaplinger   QUOTE (exobioquest @ Nov 27 2005, 08:46 AM)Wi...   Nov 28 2005, 03:59 PM
|- - exobioquest   QUOTE (mcaplinger @ Nov 28 2005, 09:59 AM)Acc...   Nov 28 2005, 04:57 PM
|- - mcaplinger   QUOTE (exobioquest @ Nov 28 2005, 08:57 AM)We...   Nov 28 2005, 05:30 PM
|- - mcaplinger   QUOTE (mcaplinger @ Nov 28 2005, 09:30 AM)How...   Nov 29 2005, 05:22 AM
- - BruceMoomaw   Apparently the Stirling version simply won't b...   Nov 29 2005, 01:18 AM
|- - exobioquest   QUOTE (BruceMoomaw @ Nov 28 2005, 07:18 PM)Ap...   Nov 29 2005, 03:35 AM
- - mike   Gasoline production is a front so the military can...   Nov 29 2005, 04:04 PM
|- - exobioquest   mcaplinger, Its unlikely the mass of the SRG will...   Nov 29 2005, 06:49 PM
|- - mcaplinger   QUOTE (exobioquest @ Nov 29 2005, 10:49 AM)It...   Nov 29 2005, 07:15 PM
||- - exobioquest   mcaplinger, The SRG has 2 55w sterling engines so...   Nov 29 2005, 07:38 PM
||- - mcaplinger   QUOTE (exobioquest @ Nov 29 2005, 11:38 AM)Ma...   Nov 29 2005, 08:24 PM
||- - helvick   QUOTE (mcaplinger @ Nov 29 2005, 09:24 PM)If ...   Nov 29 2005, 08:41 PM
||- - exobioquest   I would be estactic if anything that can provide 2...   Nov 29 2005, 08:57 PM
||- - mcaplinger   QUOTE (exobioquest @ Nov 29 2005, 12:57 PM)At...   Nov 29 2005, 10:00 PM
||- - exobioquest   QUOTE (mcaplinger @ Nov 29 2005, 04:00 PM)Eve...   Nov 29 2005, 10:26 PM
|||- - mcaplinger   QUOTE (exobioquest @ Nov 29 2005, 02:26 PM)An...   Nov 30 2005, 12:34 AM
|||- - Marslauncher   QUOTE (mcaplinger @ Nov 30 2005, 12:34 AM)See...   Nov 30 2005, 12:47 AM
||- - helvick   QUOTE (mcaplinger @ Nov 29 2005, 11:00 PM)and...   Nov 29 2005, 10:30 PM
||- - exobioquest   helvick, Sure there is nothing wrong wit MER spee...   Nov 29 2005, 10:49 PM
||- - helvick   QUOTE (exobioquest @ Nov 29 2005, 11:49 PM)Su...   Nov 29 2005, 11:10 PM
||- - RNeuhaus   QUOTE (helvick @ Nov 29 2005, 06:10 PM)I...   Nov 30 2005, 03:34 AM
||- - exobioquest   What is this: "NASA is considering nuclear en...   Jan 15 2006, 04:57 AM
||- - mcaplinger   QUOTE (exobioquest @ Jan 14 2006, 08:57 PM)So...   Jan 15 2006, 06:12 AM
||- - helvick   QUOTE (mcaplinger @ Jan 15 2006, 07:12 AM)I h...   Jan 15 2006, 09:35 AM
|||- - exobioquest   Well what is the max the MERs gets? what 900-1000w...   Jan 15 2006, 06:06 PM
|||- - helvick   QUOTE (exobioquest @ Jan 15 2006, 07:06 PM)We...   Jan 15 2006, 06:57 PM
|||- - RNeuhaus   QUOTE (helvick @ Jan 15 2006, 01:57 PM)For a ...   Jan 16 2006, 03:14 AM
|||- - helvick   QUOTE (RNeuhaus @ Jan 16 2006, 04:14 AM)Not s...   Jan 16 2006, 03:26 AM
||- - RNeuhaus   QUOTE (mcaplinger @ Jan 15 2006, 01:12 AM)I h...   Jan 16 2006, 03:04 AM
|- - mchan   QUOTE (exobioquest @ Nov 29 2005, 10:49 AM)th...   Nov 30 2005, 02:43 AM
|- - exobioquest   Well if the MMRTG is set I can only hope they can ...   Nov 30 2005, 02:48 AM
- - mike   Personally I don't think any anti-RTG-type pro...   Nov 29 2005, 08:09 PM
- - BruceMoomaw   It's about to be declared the officially, firm...   Nov 30 2005, 02:29 AM
- - djellison   Yes - it's clearly just being 'polite...   Jan 15 2006, 09:09 AM
- - Analyst   Mike Griffin said at the NH press conference MSL w...   Jan 18 2006, 10:06 AM
- - pospa   DoE's Idaho National Laboratory (MMRTG supplie...   Nov 23 2011, 12:20 PM
- - monty python   Thanks pospa. I learned a lot from that.   Nov 24 2011, 10:52 AM
- - jmknapp   I saw a presentation on YouTube where it was state...   Jul 12 2012, 08:05 PM
- - djellison   MSL has a battery, just like MER. Don't thin...   Jul 12 2012, 09:19 PM
|- - jmknapp   QUOTE (djellison @ Jul 12 2012, 04:19 PM)...   Jul 13 2012, 12:09 AM
|- - djellison   QUOTE (jmknapp @ Jul 12 2012, 05:09 PM) I...   Jul 13 2012, 07:22 AM
|- - jmknapp   QUOTE (djellison @ Jul 13 2012, 03:22 AM)...   Jul 13 2012, 02:43 PM
||- - mcaplinger   QUOTE (jmknapp @ Jul 13 2012, 07:43 AM) I...   Jul 13 2012, 04:12 PM
|- - RoverDriver   QUOTE (djellison @ Jul 13 2012, 12:22 AM)...   Jul 13 2012, 09:34 PM
- - nprev   What fluid is used in the loop, Mike? An ammonia s...   Jul 13 2012, 09:26 PM
|- - mcaplinger   QUOTE (nprev @ Jul 13 2012, 02:26 PM) Wha...   Jul 13 2012, 10:02 PM
- - nprev   Ah. Thanks!   Jul 13 2012, 10:44 PM
- - MarsEngineer   The cooling loop (heat rejection subsystem or HRS)...   Jul 14 2012, 06:06 PM


Closed TopicStart new topic

 



RSS Lo-Fi Version Time is now: 26th November 2014 - 10:04 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is a project of the Planetary Society and is funded by donations from visitors and members. Help keep this forum up and running by contributing here.