Doesn't Opportunity's situation put paid to the notion of using solar as the power source for a settlement?
If dust storms can radically reduce insolation for weeks at a time, wouldn't that seriously endanger a base?
Are there practical back-up systems/energy storage solutions that could cover that amount of time with severely reduced PV output?
even during major dust storms solar would yield at least 20% of normal values which would be enough by far to keep essential services running.
"After the last of these images were taken, Opportunity was forced to halt imaging -- and most other operations, including regular communication with Earth -- to conserve its battery power and ride out the storm."
And even harder than you indicated. The 2007 dust storm reduced light transmission by more than 95% for a period of ~ 3 weeks above Spirit, and ~ 4 weeks above Opportunity. Shutdown. Lemmon et al. 2015, Fig. 8.At a SpaceX facility "essential services" would be more than just a system clock. Propellant plant services, for example, and unavoidably. Earth-return launch windows must be honored, irrespective of weather or season. Winter storms occur: power systems must have scale and redundancy to accommodate.
Quote from: LMT on 06/14/2018 05:00 pmAnd even harder than you indicated. The 2007 dust storm reduced light transmission by more than 95% for a period of ~ 3 weeks above Spirit, and ~ 4 weeks above Opportunity. Shutdown. Lemmon et al. 2015, Fig. 8.At a SpaceX facility "essential services" would be more than just a system clock. Propellant plant services, for example, and unavoidably. Earth-return launch windows must be honored, irrespective of weather or season. Winter storms occur: power systems must have scale and redundancy to accommodate.PV power output is not entirely linear with direct optical transmission, since there is indirect light transmission.And propellant production absolutely DOES NOT have to continue during a dust storm. That's absurd. Just size the system assuming some weeks are lost to a storm, that is only a few percent of the time between synods.
xQuote from: envy887 on 06/14/2018 06:35 pmQuote from: LMT on 06/14/2018 05:00 pmAnd even harder than you indicated. The 2007 dust storm reduced light transmission by more than 95% for a period of ~ 3 weeks above Spirit, and ~ 4 weeks above Opportunity. Shutdown. Lemmon et al. 2015, Fig. 8.At a SpaceX facility "essential services" would be more than just a system clock. Propellant plant services, for example, and unavoidably. Earth-return launch windows must be honored, irrespective of weather or season. Winter storms occur: power systems must have scale and redundancy to accommodate.PV power output is not entirely linear with direct optical transmission, since there is indirect light transmission.And propellant production absolutely DOES NOT have to continue during a dust storm. That's absurd. Just size the system assuming some weeks are lost to a storm, that is only a few percent of the time between synods.When the atmosphere transmits < 5%, nonlinear response and indirect lighting aren't helpful.You realize those 4 weeks were just the peak of the storm, yes? The storm ran for 2 months. In martian winter, off-equator PV would be essentially disabled for the entirety of the storm. Imagine 5 months of winter in Hellas Basin, with daily clear-sky PV averaging 10% of summer max. Then intersperse 3 months of storms, all causing near-complete PV shutdown for the duration.Quantifying: What challenge does that scenario present to winter propellant production for, say, 10 spacecraft? How might you structure and scale things to accomplish the loading?
Quote from: LMT on 06/14/2018 07:30 pmQuantifying: What challenge does that scenario present to winter propellant production for, say, 10 spacecraft? How might you structure and scale things to accomplish the loading?Hellas at mostly 40+ degrees south is probably further than you want to go with solar as primary, and more equatorial locations are better initially. But even there, just make it bigger, and do propellant production mainly in the summer.
Quantifying: What challenge does that scenario present to winter propellant production for, say, 10 spacecraft? How might you structure and scale things to accomplish the loading?
As part of the study, we are looking at the leading three SBSP concepts, from the USA (SPS Alpha), UK (CASSIOPeiA) and China (MR-SPS). SBSP experts John Mankins (USA) and Ian Cash (UK) – the inventors of the first two concepts – are supporting our study.
Not sure if this has been covered, but this thread seems a good place for it:https://www.fnc.co.uk/discover-frazer-nash/news/frazer-nash-exploring-viability-of-space-based-solar-power-to-help-deliver-net-zeroThe UK Government is looking for risky ventures, perhaps to try and compensate for the Brexit damage. They have now commissioned a study into Space Solar Power.This is relevant to SpaceX because if the cost of launching a solar power station is less than the cost of building the solar arrays, then it might be possible to make a business case for it. Launch cost = System Weight x Cost per unit massQuoteAs part of the study, we are looking at the leading three SBSP concepts, from the USA (SPS Alpha), UK (CASSIOPeiA) and China (MR-SPS). SBSP experts John Mankins (USA) and Ian Cash (UK) – the inventors of the first two concepts – are supporting our study.
I can't help but feel the idea will run aground somewhere on the rocks of transmission loss,
continually dropping solar panel prices
and the technical uncertainties around massive solar arrays in orbit. But we shall see. It's a neat idea but I question the practicality / economics of it.
Would it be possible to harvest static electricity generated during dust storms to offset solar loss?
Quote from: Slarty1080 on 11/21/2020 01:35 pmI can't help but feel the idea will run aground somewhere on the rocks of transmission loss, JPL found ways to phase lock cavity magetrons (something that was not believed to be possible) to make low cost high power phased array transmitters in the 1970's. Quote from: Slarty1080continually dropping solar panel prices Which only work during the day. Above 800Km daylight is 24 hours long. At GEO there would be no pointer shifting but much higher losses. Quote from: Slarty1080and the technical uncertainties around massive solar arrays in orbit. But we shall see. It's a neat idea but I question the practicality / economics of it.And yet somehow the ISS stays in orbit.
Quote from: alexterrell on 11/18/2020 07:28 amNot sure if this has been covered, but this thread seems a good place for it:https://www.fnc.co.uk/discover-frazer-nash/news/frazer-nash-exploring-viability-of-space-based-solar-power-to-help-deliver-net-zeroThe UK Government is looking for risky ventures, perhaps to try and compensate for the Brexit damage. They have now commissioned a study into Space Solar Power.This is relevant to SpaceX because if the cost of launching a solar power station is less than the cost of building the solar arrays, then it might be possible to make a business case for it. Launch cost = System Weight x Cost per unit massQuoteAs part of the study, we are looking at the leading three SBSP concepts, from the USA (SPS Alpha), UK (CASSIOPeiA) and China (MR-SPS). SBSP experts John Mankins (USA) and Ian Cash (UK) – the inventors of the first two concepts – are supporting our study.Problem with using SBSP en-masse is and always has been MMOD.Micrometeoroid impacts blast away ~100x as much mass as the original impactor, and SBSP offers a huge target (you almost couldn't design something worse for MMOD unless you launch buckets of sand or something). So even if you dodge the big chunks, your solar panels will slowly get "eroded away" by untrackable MMOD. Since each impact multiplies the amount of tiny debris, you don't need too many SBSP installations before you're substantially increasing the MMOD environment in your chosen orbit.Note that while the Kessler syndrome runaway threshold depends only on the total mass in a certain orbit, a large area satellites will be eroded away into fragments faster than a compact satellite.
Interesting. Does this then, by extrapolation, ultimately invalidate the idea of a Dyson swarm as well?
by 2025 you're launching... reactors