Scott Adams Thread (Garfield Cartoonist)

[freebeard]

After happily speculating beyond the facts on other subjects, Episode 1985 concludes with him asking his audience to educate him about a robot chip fab plant on Mars. ...as you do.

I think the best place for a fab plant for Martian robot's brainz would be in Lunar orbit.

[redpoint5]

Agreed, though I suspect there are some processes where a little artificial G would help, but perhaps I'm just too used to thinking in terms of having to contend with weight. I'm thinking of the inspection tools that measure particles, or topography (flatness, thickness, etc). You set a wafer on something, and it's weight holds it on a stable and known surface to be scanned. Vacuum is quite a clean environment to process material though. Easy to keep hot things hot, too. The crucible melt wouldn't require noble gasses to displace oxygen, and the crucible itself wouldn't need to be designed to absorb oxygen and therefore have a very limited duty cycle before being discarded. I could probably think of avantages for nearly every step of the process where a vacuum, and perhaps weightlessness might be advantageous.

Reaching orbital velocity from the moon only requires about 2,200 MPH acceleration. Not too difficult, especially when there's no atmosphere to contend with. You can linearly accelerate a cube of materials to orbital velocity without much trouble or expense.

To really build things economically at scale, we either need to largely eliminate chemical rockets as the primary means of getting material off the earth, or mine materials in space. The energy expenditure of mining and redirecting the material to where you want it has to be less than the energy potential extracted in the process. If we're still burning hydrogen and oxygen for thrust, then the mining effort has to extract more than what's needed to move those materials to where we want them, as an example.

Ion engines seem to be the most feasible technology at the moment, but they aren't very powerful, and they wear out.

[freebeard]

I suspect there are some processes where a little artificial G would help,

Centripetal/centrifugal sorting to the rescue. Tell some AI chatbot to merge a space program and an acorn.

en.wikipedia.org/wiki/Stoke_Space are showing a solution for a reuseable upper stage capsule that uses a cryogenic fuel tank for a heat shield and an aerospike to land on. No grid fines, just a ring of thirty rockets.

The company operates a rocket test facility on a 2.3-acre spread near Moses Lake [WA]’s airport.[5] Their reusable second-stage design eliminates the brittle ceramic tiles that have required detailed inspections and lengthy refurbishments on other space vehicles.[6]

They have as much startup capital as SpaceX started with. One single, tested motor used redundantly on both first and second stages.

Edit: Here's this...

We are Stoke Space

[Piotrsko]

You only need to accelerate to orbital velocity if need to leave the surface in a relative hurry. Think space elevator. You DO need to dissipate the energy you acquired getting there which is why things have those heat shields. unless you can reenter really slow and take a very long time comming down.

The first stage of spacex rockets don't have much heat sheildings, and they don't reach orbital velocity

[redpoint5]

Space elevator solves all problems because no fuel is required to be lifted into space, and the energy can be recovered coming back down via regenerative braking.

I just don't think it's feasible in this universe, or at least not this planet. Perhaps a planet with no weather that spins faster and has lower gravity.

[freebeard]

Space elevator concept is compromised on any body with an atmosphere. Ever plucked a guitar string?

On the Moon, OTOH, the payload might reach escape velotcity by the top of the elevator.

[redpoint5]

Originally Posted by freebeard

Space elevator concept is compromised on any body with an atmosphere. Ever plucked a guitar string?

On the Moon, OTOH, the payload might reach escape velotcity by the top of the elevator.

That's what I was getting at when I said "perhaps no weather".

[Piotrsko]

Concept used for clarification example people, jeez....did I mention putting any kind of conductor that long into a magnetic field? Or centripedal forces?

[freebeard]

Concept used for clarification example people

Or centripedal forces?

Gravity?

The Moon would be a good candidate. No atmosphere or magnetic field.

[redpoint5]

Originally Posted by freebeard

The Moon would be a good candidate. No atmosphere or magnetic field.

My dream is to pedal a bicycle at 150 MPH on the moon, given the right gearing.