New Mars Forums

Solar energy is a free, it will be around for billions of years, a near inexhaustible infinite almost limitless resource, yet harnessing it is a relatively new idea.

Solar irradiance (W/m2)     Mars 586.2     Earth 1361.0     Ratio 0.431
https://nssdc.gsfc.nasa.gov/planetary/f … sfact.html

Issues of Living....fixing your solar panels?
How Bad is the Radiation on Mars?
https://www.universetoday.com/14979/mars-radiation1/
Over the course of about 18 months, the Mars Odyssey probe detected ongoing radiation levels which are 2.5 times higher than what astronauts experience on the International Space Station – 22 millirads per day, which works out to 8000 millirads (8 rads) per year. The spacecraft also detected 2 solar proton events, where radiation levels peaked at about 2,000 millirads in a day, and a few other events that got up to about 100 millirads.

Dust Storms???
On Mars an issue could arise too Much Mars Dust and Too Little Power?

NASA’s Mars Lander Cleaned Sand Off Its Solar Panels Using More Sand
https://www.extremetech.com/extreme/323 … -more-sand

Just a comment regarding Tesla. I live in a Northern Colorado community of ~ 65,000 plus more rurally in the area. There is a new dealership in town: Tesla. My only comment about the downside is the range of EVs in the Mountain West. Upside, they are quiet and don't pollute at all.

Lets  play devils advocate saying that it could launch and land never to return once it touches down something in the future.

A sea launch ups the level of launches of fuel for the starship to reload with which is on the order of 5 to 7 starships full for payload...

Sure making the fuel from the sea water may be possible but getting the BFR first stage to the oil rig platform is a problem.

A refueling in space of liquid methane and lox have never been done let alone a mating system from one starship to another starship to at makes them possible as loading of the first ones fuel then other might be a problem....

There is nothing impossible about recovering energy from ship bow waves or indeed from traffic induced air currents.  The point is not whether it is possible or not in some idealised or abstract situation.  It is more a question as to whether it is desirable compared to other options, when the energy return is compared to the energy and money that need to be invested to make it work.  Designing a vehicle based on new propulsion technology is horribly complicated.  A balanced design needs to balance capital cost, engineering complexity, ease of maintenance, reliability, down time, operating cost (both fuel and parts replacement), safety, speed, weight, comfort, aesthetics, range and so on.  Hopefully, at the end of the design process, you have a product that enough people want to buy and can afford to buy, for you to have a market that covers initial investment costs.  Plenty of good ideas have ended up going nowhere, because they failed to achieve the best balance of customer needs.  Nothing about the design process is simple.  And the fact that some idea or other may work at some level, provides no guarantee of success unless it can provide a definite lifetime performance advantage at a competitive cost, without pushing up things like operating cost, weight or reducing system reliability.  This is why no one is using wave powered ships.  It is why wind powered cargo ships belong to history (at least for the time being).  These things end up failing - either they are too slow, too unreliable, too labour intensive, etc.   Getting them to work at some functional level provides no guarantee of success.

Good video.  Remember that wind speed increases with height.  The propeller mounted on top of the vehicle is exposed to a higher wind speed than the drag sock mounted on the fuselage.  The fuselage is travelling through a turbulent boundary layer, whereas the propeller is at least partially raised above the boundary layer.  Hence, it appears that the vehicle is moving faster than the wind, which it is, if you measure the wind speed within the boundary layer close to the ground.  But not if you measure the wind speed at the height of the propeller.  The propeller is in this instance functioning as a sail.
https://en.m.wikipedia.org/wiki/Boundary_layer

The analogy to tacking is not strictly appropriate - the effect being observed here is due to increasing wind speed with height.  Though you could conceivably tack with a land sail vehicle.  The speed can in fact exceed the speed of the wind (though not dramatically), provided that excess drag and friction are both kept low.  The concept does not in any way violate the conservation of energy.  The kinetic energy gained by the vehicle is exactly equal to the kinetic energy lost by the air, plus some turbulent energy losses that will ultimately raise air temperature.  I'm not quite sure where the reference to wave power comes into this.

The problem with powering oceanic vessels with the wind (or waves) is limited speed.  Both concepts work from a purely mechanical viewpoint and indeed the former conveyed most of the world's long distance freight before the development of steam engines.  But within a few decades of the development of coal powered steam ships, wind had all but disappeared as a practical energy source for long distance freight and passenger transportation.  Why?  The same economic forces that resulted in the rapid phase out of wind, hinder is reintroduction today.  Low speed.  Practical speed for a sailing vessel is in fact only a fraction of wind speed, due to the drag acting on the hull and the limit of thrust impulse that can be applied as a fraction of buoyant forces - thrust exerts a turning force that acts to push the keel under water.

Reducing speed has a very strong negative impact on transport economics, because the fixed capital costs and operating costs of the ship, must be amortised over a smaller number of tonne-miles or passenger miles delivered annually.  Revenue is therefore proportional to average speed.  Given that profit is only a small proportion of revenue, a small decline in average speed will seriously eat into profitability.  Using wind will of course eliminate fuel costs.  But for that advantage to outweigh the increase in other operating costs and capital costs, would suggest that fuel costs would need to be high indeed for wind power to break even.

One way of mitigating this is kite power.  Wind speed increases with height, due to boundary layer effects.  A kite can therefore access wind speeds far above those experienced by ordinary sails.  We could use this to augment propulsion in diesel powered ships right now - it has been talked about since the 70s.  Also, the kite does not need to be mounted to a tall mast, so the turning moment isn't as limiting.  I'm not sure if it is practical to tack with a kite sail.

*sniffle* I want bees. I could post a picture of my favourite honey liqueur. My girlfriend likes baklava, although she can't eat tree nuts. Anaphylaxis.

I posted that a greenhouse for cocoa trees for chocolate would have a tunnel with negative pressure so breeze down the tunnel would be faster than midges could fly. That would blow midges back into the tropical greenhouse. Bees fly faster, but we could do something similar.

Google claims maximum flight speed of Western Honeybee is 32 km/h, but I can't find a reference.

The British Bee Keepers Association: How fast can honey bees fly?

The normal top speed of a worker would be about 15-20 mph (21-28 km/h), when flying to a food source, and about 12 mph (17 km/h), when returning laden down with nectar, pollen, propolis or water.

We could just use an airlock to keep bees in.

Perhaps Musk can do it before NASA?

or
Russians are coming back?

First mission of Russia’s nuclear-powered space tug to take 50 months
https://tass.com/science/1292721

According to Bloshenko, the space tug will first approach the Moon, where a spacecraft will separate from it. After that, it will head to Venus to perform a gravity assist maneuver and deliver another spacecraft. Then, it will depart towards Jupiter and one of its satellites.

https://www.defenseworld.net/news/29641 … _Launchers
Russia, China Reach ‘Oral’ Agreement on Integration of One-another’s Manned Space Launchers