MSL's Power Source |
MSL's Power Source |
Nov 23 2011, 12:20 PM
Post
#46
|
|
Member Group: Members Posts: 153 Joined: 4-May 11 From: Pardubice, CZ Member No.: 5979 |
DoE's Idaho National Laboratory (MMRTG supplier) has released some virtual tour from their manufacturing and testing activities on the MSL unit.
Similarly as James in other thread I was surprised how is the finished unit treated without any strict requirements for super-clean environment... ... at one moment I'd swear I saw shoulders of Homer Simpson holding one plutonium pellet with pincers. |
|
|
Nov 24 2011, 10:52 AM
Post
#47
|
|
Member Group: Members Posts: 184 Joined: 2-March 06 Member No.: 692 |
Thanks pospa. I learned a lot from that.
|
|
|
Jul 12 2012, 08:05 PM
Post
#48
|
|
Senior Member Group: Members Posts: 1465 Joined: 9-February 04 From: Columbus OH USA Member No.: 13 |
I saw a presentation on YouTube where it was stated that the RTG produces 2000 thermal watts and 110 electrical watts. So only 110 watts is sufficient to move a one-ton rover around? Also it was mentioned that the X-ray instrument consumes 4 kw, so I guess there's some kind of storage to handle the peak demands?
-------------------- |
|
|
Jul 12 2012, 09:19 PM
Post
#49
|
|
Founder Group: Chairman Posts: 14431 Joined: 8-February 04 Member No.: 1 |
MSL has a battery, just like MER. Don't think of the MMRTG as MSL's power source. Think of it as solar arrays that always see the sunshine. It charges the batteries and then the batteries drive all the stuff on the rover. The battery can be recharged overnight.
Peak consumption is > 110 watts - especially when heating things before driving or using the arm. Where did you see the 4kw value for the 'X-Ray instrument' ? Only thing I can find suggests that CheMin's XRay source uses about 42 watts. |
|
|
Jul 13 2012, 12:09 AM
Post
#50
|
|
Senior Member Group: Members Posts: 1465 Joined: 9-February 04 From: Columbus OH USA Member No.: 13 |
MSL has a battery, just like MER. Don't think of the MMRTG as MSL's power source. Think of it as solar arrays that always see the sunshine. It charges the batteries and then the batteries drive all the stuff on the rover. The battery can be recharged overnight. Peak consumption is > 110 watts - especially when heating things before driving or using the arm. I wonder how expensive (in watts) driving works out to be. QUOTE Where did you see the 4kw value for the 'X-Ray instrument' ? Only thing I can find suggests that CheMin's XRay source uses about 42 watts. Check out this video: http://www.youtube.com/watch?v=F3nJSqc2Uck At the 25:51 mark he refers to a "40-thousand watt X-ray beam." I did some searching around & I think he just misspoke and meant to say a 40 KeV x-ray beam. -------------------- |
|
|
Jul 13 2012, 07:22 AM
Post
#51
|
|
Founder Group: Chairman Posts: 14431 Joined: 8-February 04 Member No.: 1 |
|
|
|
Jul 13 2012, 02:43 PM
Post
#52
|
|
Senior Member Group: Members Posts: 1465 Joined: 9-February 04 From: Columbus OH USA Member No.: 13 |
Not too bad. The killer is the heating requirement to get the rover ready to drive. That's something on the order of 600 Whrs. Is that needed to heat up the joints/bearings? So I guess the ~2000 thermal watts from the RTG are not available for that? -------------------- |
|
|
Jul 13 2012, 04:12 PM
Post
#53
|
|
Senior Member Group: Members Posts: 2504 Joined: 13-September 05 Member No.: 497 |
Is that needed to heat up the joints/bearings? So I guess the ~2000 thermal watts from the RTG are not available for that? The fluid loop that's warmed by the RTG only goes inside the rover body; the actuators and other extremities have to be heated electrically. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
|
|
|
Jul 13 2012, 09:26 PM
Post
#54
|
|
Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
What fluid is used in the loop, Mike? An ammonia solution?
EDIT: Found a reference to freon, but not sure if that's for the mechanically-pumped system used during transit to Mars or the MSL surface ops system (if they indeed do use different fluids.) -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
|
|
|
Jul 13 2012, 09:34 PM
Post
#55
|
|
Member Group: Admin Posts: 976 Joined: 29-September 06 From: Pasadena, CA - USA Member No.: 1200 |
Not too bad. The killer is the heating requirement to get the rover ready to drive. That's something on the order of 600 Whrs. And that is why the available drive time unfortunately will still depend on the season. Paolo -------------------- Disclaimer: all opinions, ideas and information included here are my own,and should not be intended to represent opinion or policy of my employer.
|
|
|
Jul 13 2012, 10:02 PM
Post
#56
|
|
Senior Member Group: Members Posts: 2504 Joined: 13-September 05 Member No.: 497 |
What fluid is used in the loop, Mike? According to http://ntrs.larc.nasa.gov/search.jsp?R=201...ICAL%2BSCIENCES both the cruise and surface systems use CFC-11 (freon). -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
|
|
|
Jul 13 2012, 10:44 PM
Post
#57
|
|
Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Ah. Thanks!
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
|
|
|
Jul 14 2012, 06:06 PM
Post
#58
|
|
Junior Member Group: Members Posts: 89 Joined: 25-January 06 Member No.: 661 |
The cooling loop (heat rejection subsystem or HRS) on the rover is very similar to the one on the cruise stage that runs around the cruise stage and down into the rover. This is based on the same design we first used on Mars Pathfinder then MER for the cruise HRS. Same dual redundant pumps on all of these loops.
I really love them. Essentially they maintain the rover body near room temperature most of the time taken from heat from the hot MMRTG that would otherwise radiate out to the Mars environment. As Paolo points out though, the rover freon only controls the temperature inside the rover but not its appendages. We need old fashioned electric heaters for that. -Rob |
|
|
Lo-Fi Version | Time is now: 28th March 2024 - 10:33 AM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE 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 funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |