Whr Figures, From various sources Options

[Nirgal]

Great news, helvick. I think we definitively need another mission extention, something like another earth year (up to sol 1350). This would allow Opportunity to complete Victoria Crater exploration and, hopefully, Spirit will be able to climb the Mc Cool hill (but probably we need a cleaning event too!).

yes: comleting Victoria exploration and Mc Cool Summit - that would be the absolute dream of the perfect mission !


so let's just pray that the hardware will last long enough ...
<sol 1350 vision>
Oppy is dragging its broken IDD on 3 wheels accross the bottm of Victoria while Spirit finishes a one-eyed McCool Summit Panorama after having creeped to the top at a pace of 2-meters-per day
</sol 1350 vision>

[helvick]

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.

[RNeuhaus]

About Oppy news are very good and what about the news about Spirit. It is matter of crossing fingers or not? Just withstand for few days until after August 8. Will Spirit survive that time?

About Nirgal's comment, how bad will be the both girls, they will end like pirates, limping on the roads.

Rodolfo

[bigdipper]

From the August 4, 2006 mission status for sols 915-921

"Spirit is collecting about 280 watt-hours of electrical power each sol from the rover's solar array"

http://marsrovers.jpl.nasa.gov/mission/status.html

[bigdipper]

From the August 11, 2006 mission status for sols 922-928

"Spirit continues to collect about 280 watt-hours of electrical power each sol from the rover's solar array"

http://marsrovers.jpl.nasa.gov/mission/status.html

The winter solstice has passed (Aug 8, 2006).

[bigdipper]

From the August 18, 2006 mission status for sols 929-932

"Spirit is collecting about 280 watt-hours of electrical power each sol from the rover's solar array"

http://marsrovers.jpl.nasa.gov/mission/status.html

280 going once, 280 going twice, do I hear 300?

[helvick]

280 going once, 280 going twice, do I hear 300?

I think she'll be hovering around this number for at least another three weeks unless we get a cleaning event but it is very good to see that the number has not fallen below 280whr at all - that definitely confirms that dust accumulation on the panels remains very low.

[bigdipper]

Three weeks later... still at 280 whrs.


Even though spirit is not doing much, she's active beyond "wake up, beep okay, go to sleep" so there's still some power margin.

The good news is that following the 8/8 solstice the sun is up a little higher every day. Sun vs dust accumulation, sun wins - right?

I figure spirit will be out and about around the third anniversary of her landing for sure. Hopefully sooner.

[Jeff7]

I assume that there's no chance of this, as it hasn't been done yet, but I'll ask anyway:
Couldn't they use the deployment motors to change the angle of some of the panels, namely the rear flap and one of the wing arrays? Or are those motors one-time use things, or incapable of moving in an "undeploy" direction?

[djellison]

It's technically possible...but to quote Theisinger..

"I would not do that"

Better to have low power than an array stuck in an upright position, and consider the power cables that have experienced almost 1000 100 degreeC swings - they'll be brittle and potentially breakable when performing a stunt like that.

Doug

[Tom Tamlyn]

According to the latest Spirit update from JPL (9/14/2006), Spirit's solar power has finally started to tick upwards, to 287 watt-hours, from a low of 277 on sol 944 (August 29).

TTT

[helvick]

Nice to see that the power situation is slowly but surely tracking back upwards. I think we can expect a couple of months of this slow but steady rise in power provided we don't have any early storms.

Time for some updated power charts and my predictions for those who want to see when Spirit is likely to be able to make a move from here.
Right now power looks like it will rise to somewhere around 340whr/sol by the time dust becomes an issue again (~Sol 1034). That's plenty of power to remain safe and healthy while staying put but a bad early dust storm could still cause trouble and the risk of one of those rises significantly as we head into the lead into the back end of SH winter at the end of November\start of December. Even if we do have some local storms the overall power situation is unlikely to drop back to dangerously low levels again this winter, at least for any significant length of time.
It is important to point out that these charts include the ~15% benefit from Spirit's current favourable tilt and without that extra boost she will be back in trouble and will remain effectively unable to move anywhere until she gets a good cleaning. My guess is that she will need to be able to generate 400whr/sol under current conditions (with tilt) or around 340 whr/sol (without tilt) before they make a serious attempt at moving any distance. A minor change in orientation is currently on the cards but that is going to be a very delicate manoeuvre as they will want to maintain that tilt power benefit.

Chart without any cleaning events.


Were we to see similar events to last year then the peak power output would rise to around 600whr/sol from around Sol 1090 (end of Jan 2007). That would certainly make a dash for Home Plate very possible. Here's hoping.
Chart with cleaning events as per last year.

[centsworth_II]

... I think we can expect a couple of months of this slow but steady rise in power provided we don't have any early storms.

[or] ... until she gets a good cleaning.

Storm season is also cleaning season. Last season as I recall, the positive effect of cleaning events outweighed the negative impact of dust buildup. I wonder if that would generally be the case or if it was luck and there could just as easily be a season where cleaning events were no match for the dust buildup. I guess all bets would be off in a months-long global dust storm. I hope we go another season without one of those!

[helvick]

I wonder if that would generally be the case or if it was luck and there could just as easily be a season where cleaning events were no match for the dust buildup.

That could be the case but the long term average net deposition rate must be extremely low or else the entire planet would be just dust. The big problem for the rovers is that the very fine stuff sticks to the panels and that requires some event to kick free (either the "clumping" theory and\or high wind gusts). It will certainly be interesting to see if the pattern of cleaning that we've seen repeats this year and thats experimental data that Spirit can gather without doing much at all.

I guess all bets would be off in a months-long global dust storm. I hope we go another season without one of those!

Likewise. A global storm that pushed Tau up into the 3-5 range would drop Spirit's power generating capacity down to below 50 whr/sol. She might be able to sleep through it as night time temperatures could remain relatively high but I suspect that a long storm would be terminal.

[bigdipper]

"SPIRIT UPDATE: Solar Power Is on the Rise as Spirit 'Follows the Water' - sol 970-976, September 29, 2006:


Solar power levels on Spirit are slowly beginning to rise again following a winter low of 275 watt-hours on Martian day, or sol, 933 (Aug. 18, 2006). One hundred watt-hours is the amount of electricity needed to light one 100-watt bulb for one hour. This week, the rover's power levels rose to about 296 watt-hours."

--latest Spirit Update

When do we roll? 300? 400? I can hardly wait.