New Mars Forums

A thing that has confused me about chemical rocket engines, is do they have to do their burns in the shortest time possible to get the most desired effect?

Of course, when rising though the Earth's atmosphere maximum tolerable thrust is desirable as you want to reduce gravity losses.  For example, the wrong thing to do would be to hover above a point until the propellant are all consumed.
But the machines being lifted can tolerate only a certain level of force towards the maximum, which would be an explosion, I suspect.

So, I suspect it would be some time before the rotating detonation engine could be used to make a machine rise from the surface of the Earth, though the Earth's atmosphere.

But once in LEO, and practical vacuum in orbit, could a small engine be used to do a long, small burn to propel a ship such as the Moon or Mars?  The presumed oscillations which apparently may be part of the device might be managed if it were a small engine, relative to the mass of the machine it was mounted on, a spacecraft.

That is my guess, that it might be the lowest hanging fruit for the new engine described.

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My response to posts #2097 and #2098, even though perhaps I should not dare.

With this new system they have chain of many new things that they are working on and each one may affect the others, so no surprise that it is messy.  (I respect your assertions GW Johnson).

They have tried various things that failed and then had to try another.  They tried tumbling the stack to separate the two stages.  That did not work well.  At least they had good sense to try another.  The hot staging.  I think they may be getting it cleaned up now.

I think the Superheavy is coming along nicely now.  I am impressed anyway for how much that is worth.  If they can implement the new sideways dive method, then they can probably afford the dry mass of the device between stages, to stay attached to the Superheavy.  And if the Raptor 3's are as good as they claim, then Superheavy, could really be a gem, I think.

But Superheavy, resembles a oversized Falcon 9 1st Stage.  They changed to Methane, and use Stainless Steel.  As I understand it they have to burn less propellants to protect the Superheavy from entry stresses as the Stainless Steel may endure more abuse than the Aluminum/Lithium alloy that I believe is used for Falcon 9 1st Stage.  The great hope, not yet proven is that the Superheavy will not coke up like the Falcon 9 1st Stage.

I don't know if they are ever going to put landing legs on the Superheavy.  I guess never say never is what to say about that.  The catch tower makes me nervous, but if it works, it is very efficient as the idea is the Superheavy could eventually be restacked in a few hours/days, refilled and used again with little maintenance.

So, not all of this is proven, but I am very impressed with the Superheavy already.

And we can still understand why SpaceX is not publicly traded on the Stock Market, as if some bean counters got ahold of it at this point they would likely circle back to the past, to make quick bucks.

At this point what a circle back would look like would be model Starship after the Falcon 9 2nd Stage.  No reuse, abandon to splash in the ocean.  Drop 2 fairings on the way up, and deploy Starlink, and other payloads.

Then you could go ahead and try to build the 2nd Stage from a lighter material.

And I am not sure that eventually they may not do some of that as an option.

But really it is far better for the future if they do not chicken out, for chicken feed.  No guarantees that they can make the Starship worthwhile, but I think there are lots of chances that they can get it done.  And if they do, it will really be something.

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Yes indeed.  You might like this if you have not seen it before: https://www.youtube.com/watch?v=TNRQFKV … saacArthur  Quote:

So, a space elevator between Pluto and Charon, crossing though the barycenter.

The idea that "2017 OF201" may have a hundred or more siblings, is of great interest.  As you have pointed out the hill spheres maybe enormous.

In taking these things largely apart, quite a lot of structure could be manufactured.  One somewhat weird idea would be to extract the materials and make a giant ball of "Foam", encompassing the entire Hill sphere if that were possible.

Foam: https://www.slideshare.net/slideshow/fo … 6/24926136
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If the "Foam World" were made in the shape of a red blood cell this might help to radiate heat out.

https://www.gettyimages.com/detail/phot … /637422184
Image Quote:

So converting a whole dwarf planet to one shape like one blood cell and having an internal structure like foam, maybe cells in cells so to speak.

The hill sphere would be modified by the warping of the shape.

A cross between a torus and a disc.

In the case where the world is beyond the Heliopause, then perhaps to be able to collect interstellar gasses and dust.  A greater density may exist where the solar wind collides with the interstellar winds.

Various cells within could have features like spin gravity devices, and seas perhaps.

So, perhaps worlds that will be giant spaceships, and seek out other dwarf planets to convert, perhaps even rogue dwarf planets.

Even to travel to "Feed" on the Heliopause of other stars, to migrate though the galaxy and maybe even further.  Even the spaces between galaxies are said to have some stars.

An interesting fate for the human race and their machines, if the higher powers allow it.

If there are as many dwarf planets as may seem at this point, and if fusion does become practical, then rather than a great interest in Dyson Spheres, which seem to be of doubtful merit, this would be the path of higher civilizations, and they would be rather hard to detect wouldn't they.

So, Isaac Arthur might consider carefully interested Aliens, perhaps.  If they were interested, they could take over our robots.  In fact they would introduce us to robots, so that we would depend on the robots that they would take over.  Scarry!, but not Scarry.

Actually other than anthropology I don't think they would want to spend their time messing with us or messing us up.

But they could keep an eye on us from a distance once they introduced us to computers and robots.  We will probably be beaming information between planets and they could probably intercept it.

But they might never introduce themselves to us.

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So, I have been thinking what would be next after working with relatively simple bulk materials, and having initial donations of sophisticated materials from Earth.

Perhaps we mimic the human progression through materials.  Stone age, various metals ages, Industrial ages, and finally we seem to be entering a higher-level robotics age.

In this projection of possibility robots have already been injected well before their natural progression.  But these then are donated from Earth. 

If Mars is a child, then a child must be offered strong support to become adult enough to thrive in a very difficult situation which might offer high rewards. That is what Mars is.

Blue Origin and Metalysis offer entry into the metals ages, but solar may not keep up.  The solar that Blue Origin can create is relatively low efficiency.  On the Moon that might be worthwhile, but on Mars, a lesser solar flux exists.

So, it looks good that in the USA it appears we will encourage the production of small nuclear reactors to power data centers.

So, if the correct political, geopolitical, and technical barriers can be overcome, it seems to me that the donation of nuclear power plants of a small size, makes sense.  One thing that the population of Mars Robot/Human can offer back is science data.

So, possibly, this gets a Mars into the age of Metal production.

I may rest this line of thinking now, because I have already projected very far into the future, and the more time projection you use the more likely that your concepts will not resemble what will actually happen.

I may however return to interest in our best planet, Earth.

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I think we should keep the faith.

They are going to stop using Ullage gas to orient the ship and according to what I have read they will install gyroscopes.
They also hope to find a way to use the flaps to right the ship, even if it comes in upside down.

In an actual orbital situation, they could drain off the leaking tank so that no more spin impulse would occur.  Then the gyros could hopefully correct it's spin.  It is also hoped that the flaps could then assist in orienting the ship.

Then it would have the Header Tanks to try to get into the atmosphere with and land.

But that may leave a problem.  Will the ship be stiff enough without, pressurization of a main tank?  Well, that is an important question anyway, as the main tanks may have completely boiled off by the time a ship made it to Mars.  I don't know if the ship needs main tank pressurization to travel though the atmosphere without breaking up.

But in the case where the ship had gone orbital, and had such a mishap, it might be possible to plug the leak, and refill then ship if needed.

The Block 3 Ship will have the raptor 3 engines which are better, I hear.  Also, it may be of a longer length, so may not have the same type of stresses.  Maybe it will be better or worse.  I would not know.

If it is worse, then perhaps they will indeed need to move back to the block 1 size.

But I think it is going to be some time before these ships will be trusted for human space flight.  A number of years.  So, there is time to work the kinks out, and use it for freight.  In Lunar Operation though the criteria will be different.  It will not have to airbrake to the Earth's surface and then do a landing on a 1 g world.  So, it may be safe for humans for Lunar Missions much before safe for humans Earth or Mars.

Patience Required..................

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I am a fan of SpaceX, but I hope the Blue Origin people can do their own path to good accomplishments.  It looks like a valuable device.  I would think that if it could be propelled to Mars with an electric rocket that might make it even better.

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I consider this to be a nice item: https://www.bing.com/videos/riverview/r … 6d6c5526de  Quote:

It seems that they have a depot that will store Hydrogen and Oxygen without boiloff.

Also mentioned is sourcing Oxygen from the Moon at a favorable price, either from ice or from regolith.

It is intended to be able to deliver propellants to the Moon or Mars orbits, it seems.

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I want to work a bit more with the materials from this post: https://newmars.com/forums/viewtopic.ph … 50#p231950  Quote:

Instead of bifacial solar panels we could build a building and use the East and West walls, as mounting for solar panels.

Here is something that may have application on both Earth and Mars:

On Earth the advantages can be protection from Hail.  Also the heated air will become accessible at the bottom of the Eaves of the House.  Obviously strong wind will interfere with that when it occurs.  If you wanted to put a glaze in front of your solar panels, that would correct that problem.

On Earth a problem with this system would be that you need heliostats for both the East and West side, and they would only be of service half of the day.  But if your Heliostats can be mobile, then they can move from East to West and then West to East.

I really have been thinking about this more for Mars.

I am really looking to shelter robots.  A room temperature of -10 Degrees Centigrade may be preferable.  In the thin air this may help with cooling of motors.  I suppose there could be a minimal pressurization of the buildings which could help with cooling.

The buildings could be very long north/south, or there may be multiple instances of the East and West of each other, with the Heliostats between them.

So, my intention in this is to harvest both the electric and the solar heat.  For Mars, I am hoping that warm Mars air can be sucked in and filtered of dust and then compressed to increase the heat.  In the manner of a heat pump.

And that the collected heat, could be stored into mass, solid or containers of water.

In the event of global dust storms or high latitude winters, the robots might hibernate in a huddle around a nuclear power source.

So, most work would be done off of solar energy, but nuclear would keep the work force alive.

A Norwegian heat pump can reach 180 degrees C, so that would be a hoped-for capability.

Here is a drilling method for heat pumps that might be useful in this scheme: https://cleantechnica.com/2025/01/21/bo … lications/
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This may actually be sufficient to keep robots safe during a global dust storm of high latitude winter.  But it would be nice to have some nuclear.

The exact nature of the buildings could be different than I have shown, but the method is illustrated.

The method may be able to harvest both heat and electricity from sunlight.  Also a vertical surface, is likely to be possible to keep clean in the Martian environment.  A vertical surface may shed more heat from convective heat flow than a more horizontal situation.

I would be happy to get comments on this.

In this other topic I have made my case that robotics that are emerging should be able to build quite a lot on Mars even before humans might arrive.  https://newmars.com/forums/viewtopic.ph … 41#p232041

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Request from the just previous post:

I say yes, and grant the requested permission.  I hope the person requesting will be OK.

I expect that I will never know what post or what it was about.

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Continuing, the Starships could have their cargo compartments cut off, and kept in a relatively low Earth orbit to construct things with. 

The "Locomotive" might travel to the Moon to be of service there.  If a Starship has a dry mass of 120 tons, perhaps the Locomotive might be 60 to 80 tons dry mass.

If Oxygen begins to be produced from the regolith of the Moon, then the Ships may in part be refilled on the surface of the Moon, to allow repeated excursions to orbit and to land.

Depots, sent from LEO to orbit the Moon could supply Methane.  The ships would lift things like extra Oxygen or regolith to orbit.  Regolith might in this case be treated and refined materials.  For instance Iron Oxide.

The Locomotives would run until failure at which point they would become scrap metal.

So a stream of Oxygen may travel from the Moon to LEO in the form of Oxygen or perhaps Iron Oxide, or Aluminum Oxide.  A Stream of Methane would travel from LEO to the orbits of the Moon.

The scrap in part can be converted to propellant for Magdrive or Neumann Drive.  This will be the means to transport cargos from Low Lunar Orbit to Low and Medium Earth Orbits.

Similarly some scrap from the cargo sections of the Starship will be converted into propellant for Magdrive or Neumann Drive, to facilitate the transport of bulk mass from Low and Medium Earth orbits.

So, we would not be burning liquid fuels, except to rise from a worlds surface to an orbit and back, and except for the case of moving humans swiftly between the Earth and Moon.

Should this system have enough excess Oxygen then it might help fill ships destined for Mars.

I think it could be good.

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OK, I now can find the video, that I did not get yesterday in the last post: https://www.bing.com/videos/riverview/r … &FORM=VIRE
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From post #86, just previous:

In post #85, I did some rough calculations about the value of a Starship sent to LEO and then moved to a rendering facility for reuse/repurpose/recycle: https://newmars.com/forums/viewtopic.ph … 16#p232016

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If SpaceX were to build 1000 ships a year, and left 250 of those a year stranded in LEO, then that would be almost 21 ships per month.  Rather than to burn them in the atmosphere, lifting them higher slowly with an electric rocket tug could make sense.  So, then you would have an input of 30,000 tons of mostly metal, to such a rendering facility each year.

One thing you could do to start with is remove the cargo sections from the rest of the ship, and to repurpose each of them.  Cargo sections to be joined into space stations perhaps, or maybe large ships to travel to Mars.  The Propulsion sections could be converted to land on the Moon, and become a resource there, as it would be hard to make high quality Stainless Steel on the Moon, at least at first.

Some materials might be converted into propellant for Magdrive or Neumann Drive.  This might be used to move Stranded Starships, from LEO to a higher orbit where rendering facilities might be created. 

Also possible to look into might be power stations of some kind.

So, at some point you would need to do a calculation.  How much value does a Starship have returned to the Earth, against how much value it may provide, being rendered into beyond LEO uses.

You might choose to return a certain portion of the Starships, and leave the balance in orbit for conversion.  Obviously if they are to be used in a rendering facility to convert, you would not be likely to bother with a heat shield, or other landing parts such as Flaps and Motors.

Things like gyros, avionics, and engines might be returned to Earth in some cases.

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Here are some interesting claims: https://www.youtube.com/watch?v=FcollPP … aceXReport
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The new Block 3 will be stretched and use Raptor 3 engines, and is said to be able to lift 200 tons to LEO, fully reusable.
That system is said to be able to lift 400 tons to LEO, if the whole rocket "Thrown away".
Block 3 will have 3 instead of 4 grid fins.

The old ships 10, 11, and 12 will be outdated so are either for scrap or for destructive testing.

Block 3 will not launch on pad "A", but will launch from pad "B".

I speculate that you could lift ~300 tons to orbit, reusing the Superheavy, but leaving the Starship in orbit.

If they do get to the rate of build of 1000 Starships a year, what if 250 of those were made to not return to Earth?
That would be 100 extra tons to LEO per each of the 250.  And the ships would still be in LEO or maybe boosted up a bit higher.  So, an extra 25,000 tons to LEO.  And if the ships are 120 tons dry mass then another 30,000 tons of metal.  The ships as well if refilled might be used for an additional service.

Additional service might be construction of Space Stations, as well, or the rendering of some of the metal to propellants for Magdrive or Neumann Drive.

If refilled some of these ships might be able to fly one way to land on the Moon, to become a resource for bases there.

They also might be refilled to send massive probes to other worlds.  In that case the second use of the Starship would be finished by abandoning it to a solar orbit or around another planet, I suppose.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Another interesting idea would be a "Shortie" Starship.  Where SpaceX very much is into stretching Starships, by shrinking the tanks, and the cargo compartment the dry mass might be reduced in these cases.

Where there is interest in moving from 6 engines to 9 on the stretched Starships, could a shortie get by with 2 Sea levels, and 2 Vacuums?  That would reduce dry mass a little and also reduce engine cost a bit.

This would not be a Mini-Starship that Dr. Zubrin wants, but it might give similar service.  So, you might partner a "Shortie-Starship with a Full-Starship for a flight to Mars.  As for the Moon, a "Shortie-Starship" might be a better fit.
It might be more suitable for bringing people back from Mars as to use less propellants that have to be manufactured on Mars.

Particularly if the Shortie-Starship could be refilled in several places.  Oxygen on the surface of the Moon, and from Depots placed in useful positions in orbits of the Moon and the Earth.  The Depots might be positioned there by electric-plasma propulsions.  A Shorty would be less inclined to tip over, and also might disturb regolith or landing pads less.

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Dr. Zubrin seems to think that a ship that can deliver 30 tons of payload to the Moon or Mars, might be quite useful.  Perhaps a "Shorty-Starship" could.  What if it's dry mass were 60 tons instead of 120 tons?  40 tons?

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