New Mars Forums

Hopefully it isn't carrying protomolecule :-)

The object appears to contain nickel with far less iron than a sol comet.  CO2, but little CO or water ice.  Strange indeed.  But it did form in a different environment to the solar nebula.  Different is to be expected.  Maybe in the future we will find comets with different isotope ratios or comets full of gold or uranium?

Electricity offers the benefit of being easily transmissible.  On the demand side, electrical machinery is also very compact and allows high power density.  In factory environments, electrical machines have the advantage that changing factory layout is easy and machinery can be positioned for maximum productivity.

The disadvantages of electricity are inherent complexity in generation, transmission and use.  Electrical systems are complex, not suitable for local manufacture and typically require exotic materials and programmable controls.  Electric grids are also demand driven.  This makes them unsuitable for energy sources that have naturally intermittent supply.  Energy storage and backup power tend to be counterproductive, as both impose substantial additional capital and operational costs that makes delivered power very expensive.  This problem is clearly evident in European countries that have embraced wind and solar power.

Rolling blackouts have sometimes been suggested as solutions to these problems.  Unfortunately, this introduces problems of its own.  Firstly, businesses dependant on electrical power lose all productivity when it is cut off.  In some cases, loss of power can actually cause damage.  Secondly, when power is shut off and breakers fail open, these must be manually reset.  This is costly and time consuming.

A potential solution to these problems is to remove certain applications from dependance on the electric grid.  Hydraulic and compressed air power systems, are somewhat more cumbersome to install than electrical systems.  But they have the advantage of being simpler, similar in terms of efficiency and offering the same benefits of flexibility and power density as does electrical power.  Hydraulic systems do not need exotic materials or complexity inmthe ways that electrical systems do.  Most components can be made from steel, with limited use of polymers for seals and flexible couplings.  This makes hydraulics more suitable for local manufacturing.  It is somewhat less practical to use hydraulics to transmit power over long distances.  But for local power networks it is straightforward.  Power can be switched on and off by opening and closing valves.

In a small hydraulic network surrounding a mechanical windmill, intermittency is easier to manage.  With only a handful of different users for the power in close proximity, it is possible to switch off certain loads quickly, by closing valves.  Hydraulically powered heat pumps and air compressors can serve as dump loads that will not be active unless wind power is above certain thresholds.  Swimming pool heating, heat for cooking, warm water for district heating, cooling for large underground freezers, are all systems that can be engineered with large thermal inertia through thermal mass and insulation.  Other more direct mechanical applications, like a laundry and power to a machine shop, need power to be more reliable.  Grinding is an application that can be switched on and off, provided that aggregate productivity is maintained across a whole year.

In this way, I can see applications for mechanical windmills providing services for a town.  Intermittency is a problem that we can work around at a small scale in ways that is not practical in a large scale electric grid.  Hydraulic power transmission allows flexibility and local manufacture of machines in ways that are not possible with electricity.

Even tiny planets could support ecosystems.
https://www.sciencealert.com/even-tiny- … scientists
The findings suggest that worlds 2.7% of Earth's mass could still support habitable atmospheres.  That is a little over twice the mass of Luna.

The rotor is safely back on the ground.  I am going to begin upgrades tomorrow after work.

I have no idea how practical the idea is.  But I envisage the microprobes being mass produced by the billion.  The probes would be extremely simple, with a beta voltaic generator, powered by a long lived fission product isotope like technetium-99.  The beta voltaic generator would charge up a capacitor.  When the capacitor reaches full charge, it releases a pulse of power generating a radio ping.  It would do this maybe once every day.  Two detectors seperated at different sides of the solar system could triagulate the position of the microprobe.  Any change in frequency of the radio pulse would indicate that the probe is experiencing velocity change due to a gravitational field.  But each detector would measure the doppler effect differently, allowing both the magnitude and direction of the acceleration to be tracked in real time.  Near Earth infrared telescopes could then focus on the area, searching for the IR signature of a body.

I wonder if the probes could be printed onto sheets of polymer?  They could then be cut out like stamps.  Solar sails could be used to accelerate batches of the probes to solar escape.  A flyby of a solar system body like Jupiter could be used to scatter the probes at different velocities.

Technetium-99 is a pure beta emitter with a half-life of 211,100 years.  This sets an approximate lifetime for the probe.  This isotope makes up about 6% of fission product waste, so should be an abundant material.  If ejected from the solar system at 30km/s, 200 trillion km before it becomes defunct.  That is 21 light years.

The reverse of this option is the downdraft chimney.  For this idea, water is sprayed at the top of the tower, cooling the air, which is then denser than the air around it.  The dense air sinks down the tower, flowing through a turbine at the bottom.  The plus side it that you don't need a huge greenhouse to make this work.  This might be a good option in places with hot climate.  Potentially, seawater could be used rather than freshwater.  In places that are arid, this would add moisture to the air and could therefore create rain.  It would also create a layer of cool air close to the ground, which would reduce the need for air conditioning.

There are some states in the southern US that could benefit from this technology.  The towers could be made from thin concrete shells, rather like cooling towers.  In additional to generating power, the towers coukd be used to cool urban areas, either by venting cool air at the bottom of the tower creating a dense, ground hugging layer, or by piping cool air to specific buildings.

Individual houses could be cooled using small downdraft towers.  This could replace other types of air conditioning and could be entirely solar powered.  Alternatively, multiple houses could be clustered around a single downdraft tower, with each supplied with air via buried ducts.  A well designed system could provide cool air without any expenditure of power.

The article concerns microreactors, generating around 100kW of heat.  These reactors would be useful on Mars and have the benefit of a high level of passive safety, due to their small size and ability to lose heat radiatively.

But they have other problems.  High neutron leakage from small cores tends to drive the need for higher enrichment.  Such reactors require more fissile material per kW of power generated, which is undesirable from an economic standpoint.  Finally, there is no hope of reactors this small becoming a large scale solution under present regulatory arrangements.  The burden of management imposed by organisations like the NRC and ONR would make it very difficult for powerplants smaller than several hundred MW to remain in business.

Of course, the consequences of a nuclear accident scale with power output.  A 1000MW reactor presumably carries 1000x the fission product inventory of a 1MW reactor.  So an accident in a smaller plant will not have the same societal effects.  It may be possible to simplify regulatory arrangements on the basis of this and the high level of passive safety inherent to such a plant.

Last night we had a storm that damaged the windmill.  It actually ripped one of the spindles out of the nacelle.  Of the many ways that this machine could fail, this was one that I never expected.  I need to bring the rotor down to repair it.  That means putting scaffold back up.  Doh!

I had bought some rollers from Temu.  However, when I fitted them to the table where the rope is seen to rub, they produced a lot of noise and friction in operation.  Oil and grease didn't seem to help, so I removed them.  This evening, I installed some brass rollers from an old set of windows that my father had dismantled.  These are about 100 years old, but work better than the Chinese imports made in 2025.

I also took your advice and added an idler wheel, as the rope was too loose to grip the pulley under a strong wind.  Tomorrow the forecast for my location shows a 20mph westerly wind.  This shoukd be sufficient to power the windmill even with the trees attenuating the wind.  Once the trees are gone, the wind should be sufficient to drive the machine most days.  I could add another set of blades to the rotor to increase the torque generated in a given wind.  But I would rather not, as weight is already significant and adding blades is a lot of work.

The completed machine with rope drive attached.

I'm sure that it is possible to use the grid for backup power.  But that requires that the turbine generate electricity and that there is some means of switching between the turbine and the grid for power.  My project uses the wind to generate direct mechanical power without electricity.  This is much simpler to do and I was able to make all of the equipment from simple and mostly recycled materials in my home workshop.  Purely mechanical systems are things that most people can build for themselves, using low embodied energy materials.