Whr Figures, From various sources |
Whr Figures, From various sources |
Feb 6 2006, 03:39 PM
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#1
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Founder Group: Chairman Posts: 14433 Joined: 8-February 04 Member No.: 1 |
I've been looking at the new entries at the PDS for WHR quotes, to compile as good a list of actual quoted Whr values as I can......so if you find one, add it to this thread and I'll update this post with figures....any source as long as it's an actual figure and an actual sol.
B0515 - 418 Whrs B0522 - 462 Whrs |
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Jul 20 2006, 02:37 AM
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#2
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Senior Member Group: Moderator Posts: 2262 Joined: 9-February 04 From: Melbourne - Oz Member No.: 16 |
Helvick.
One thing that struck me last night. The amount of incident sunlight absorbed by dust on the panels must be quite inclination dependent. (Think of the size of the shadow of a dust grain, or the path length through a thin dust film as the the angle varies) Maybe this is the reason for the power falling off faster than expected? If this is the case then as we appoach the solstice the rate of change of this effect should decrease and even better, give more power than expected as spring arrives. Does this make any sense? James -------------------- |
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Jul 20 2006, 06:11 AM
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#3
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Dublin Correspondent Group: Admin Posts: 1799 Joined: 28-March 05 From: Celbridge, Ireland Member No.: 220 |
Helvick. One thing that struck me last night. The amount of incident sunlight absorbed by dust on the panels must be quite inclination dependent. (Think of the size of the shadow of a dust grain, or the path length through a thin dust film as the the angle varies) Maybe this is the reason for the power falling off faster than expected? Interesting idea - this certainly would make sense for beam insolation. The assumption that I made was that the "loss" in power due to dust could be described by a simple efficiency percentage as that seemed to be what the mission planners had thought. Now that I think about it it doesn't make a lot of sense to think it could be so simple. I think I need to try to model this to see how it might effect power throughout the day and as the Sun's altitude changes from Sol to Sol. Diffuse light (which accounts for around 30% of power generated at the moment) is definitely not affected in the same way - by definition it comes from all incident angles after all. |
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Jul 20 2006, 10:26 AM
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#4
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Member Group: Members Posts: 713 Joined: 30-March 05 Member No.: 223 |
Hi Helvick,
do you also have current dust accumulation loss rate estimates for Opportunity ? (see also my former posting above) |
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Jul 22 2006, 12:16 PM
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#5
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Dublin Correspondent Group: Admin Posts: 1799 Joined: 28-March 05 From: Celbridge, Ireland Member No.: 220 |
Hi Helvick, do you also have current dust accumulation loss rate estimates for Opportunity ? The problem with Opportunity is that there is very little data - the last update I can find that mentions power was the 400whr number at the end of May. Using the same assumptions as for Spirit above I get the following for Opportunity at the moment. Power has just about hit its lowest level for this winter (~370) and will stay around there for a while (say around Sol 925\930) and then will slowly creep up to ~420 at around Sol 1080 and then begin to decline back to 300 whr as Tau increases with SH Spring\Summer. Any cleaning events will significantly change that of course. |
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Jul 22 2006, 06:33 PM
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#6
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Member Group: Members Posts: 713 Joined: 30-March 05 Member No.: 223 |
The problem with Opportunity is that there is very little data - the last update I can find that mentions power was the 400whr number at the end of May. Using the same assumptions as for Spirit above I get the following for Opportunity at the moment. Power has just about hit its lowest level for this winter (~370) and will stay around there for a while (say around Sol 925\930) and then will slowly creep up to ~420 at around Sol 1080 and then begin to decline back to 300 whr as Tau increases with SH Spring\Summer. Any cleaning events will significantly change that of course. Thanks Helvick ! It's encouraging, that even with your conservative estimate and even without cleaning events, there seems to be sufficient power for Oppy until at least around Sol 1150 BTW.: I really love those excellent diagrams of yours |
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Jul 30 2006, 06:05 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 |
More good news on the power front, this time for Oppy - from todays JPL update:
QUOTE Over the past 50 sols the team noticed a gradual cleaning of the solar panels similar to a more-sudden cleaning event experienced one Mars-year ago in "Endurance Crater." Removal of some of the accumulated dust on the panels allows greater production of electricity from sunlight. Opportunity's solar panels are now producing just over 500 watt-hours per sol. So Oppy is in very good shape and getting better. The following chart shows that even without any further cleaning Opportunity should have enough power generating capability to last through to next winter. I think I'm going to break out the Laphroaig and have a wee dram to celebrate. Spirit hasn't been so lucky (yet) but they have confirmed that her power generating capability is not expected to fall below 275 watt hours which is very good news. |
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Jul 30 2006, 10:04 PM
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#8
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Senior Member Group: Admin Posts: 4763 Joined: 15-March 05 From: Glendale, AZ Member No.: 197 |
I think I'm going to break out the Laphroaig and have a wee dram to celebrate. I see you like to celebrate in style. -------------------- If Occam had heard my theory, things would be very different now.
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Aug 1 2006, 10:37 PM
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#9
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Dublin Correspondent Group: Admin Posts: 1799 Joined: 28-March 05 From: Celbridge, Ireland Member No.: 220 |
I see you like to celebrate in style. :-) The Islay single malts are ideal for special events - Laphroaig in particular really is a delightful mix of heaven and hell that I can only ever drink slowly and in small quantities so there's no fear of ending up with a hangover afterwords which is definitely a good thing since a Laphroaig hangover would probably be an awful thing indeed. |
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