New Mars Forums

I have integrated the process of decelerating Halley's comet to hit Mercury, Venus or the Sun. Mars is not a good target for Halley's.The idea of these calculations proves that man can use comets to hit planets deliberately

Email to NASA's NIAC Ron Turner:
"Below is a conversation I had with AI about self scalping nozzle that you might be interested in because comets being made of ice means that we can create our own nozzles to increase detonation coupling efficiency. I had a deeper look at the related papers for PI defence, it looks like it could work even better if they were on a stratospheric platform that way they wont get destroyed by the incoming comet on Mars if they are thousands of km away from ground zero at a high altitude say 10km. In fact this system if done the same way on Earth on floating airships will give them higher efficiency as they are launched above the troposphere and have clearer line of sight to the target with sensors not occluded by clouds."

ChatGBT:

Me:
I was thinking that each dotonation would leave a crater and then a crater within a crater and eventually we end up with a practical nozzle so that we can eventually get close to 80% coupling

AI:
Reasoned for a second
That’s a concept sometimes referred to as a “self-sculpting nozzle.” With each successive detonation, a crater deepens and takes on a more “bell-shaped” or “nozzle-like” profile. This shape can, in theory, capture more of the bomb’s energy and direct it into vaporizing cometary material, thereby increasing the coupling efficiency.
How It Might Work
Initial Detonations:
The first few blasts are not very efficient, as a large fraction of energy escapes into space.
However, each explosion excavates a crater, exposing fresh surface area and potentially creating walls that reflect or contain a portion of the blast.
Progressive Shaping:
As the crater gets deeper and narrower, later explosions occur in a sort of “cavity.”
This geometry acts like a convergent or bell nozzle, helping to direct more of the expanding gases and energy back onto the comet’s surface rather than letting them radiate away spherically.
Higher Coupling:
With a more focused geometry, you can approach higher fractions of energy coupling—some studies speculate up to 80%—because the energy is partially contained and directed into the comet.
The repeated blasts effectively reduce losses to open space.
Challenges to Consider
Structural Stability: There’s a risk of shattering or fragmenting the comet if the blasts become too powerful or the crater becomes unstable.
Precise Placement: Each detonation must be positioned carefully so it doesn’t just punch a hole out the opposite side, losing the chance to build a self-enclosed cavity.
Material Properties: If the comet is extremely porous or loosely bound, it may not form neat crater walls; the material could just slump in or break apart.
Feasibility
While theoretically plausible, the “self-sculpting nozzle” approach is complex. In practice, engineers would have to carefully tune:
Bomb yields,
Placement depths,
Timing between detonations,
to incrementally shape the crater without destroying the comet. But as a thought experiment, it’s a fascinating way to push coupling efficiency beyond the simpler estimates of 30–50%.

For Halley's comet you need a different comet with a different trajectory.

To prevent the strike on Mars from becoming too violent it can be pulverised using this method of desteroying near Earth Asteroids
https://www.nasa.gov/general/pi-planetary-defense/

Yes I think it's worth planning a way to recover the expended "fuel tankers". Could equip them with an ion/plasma/VSMIR drive or maybe let them enter Martian Orbit but take longer to do so and they can do the aerobraking thing too but over a much longer time vs the crewed ship. Or like you said, let them return to Earth over a much longer time period. Probably just to LEO and let them get refurbished in orbit and then refueled for yet another mission. Like the first stage Heavy Booster but in orbit instead of on the surface.

Oh this is like the Martian Igloo idea that Dr Zubrin came up with and I came up with it too after him but independently without realizing the idea already existed!

https://photonbytes.com/2024/05/17/mart … ter-igloo/

I think this is definitely do-able and easier to do but you have the same problem of needing airlocks. If you have a vertical elevator/lift to take people up and down I suppose it wont put the rest of the habitat down below at risk if there are any human/mechanical failure.

UPDATE 2.0: Chat GBT corrected it self youre right it's going to be 576MPa according to my 2nd conversation with AI, and Martian Basalt compressive tolerance ranges from 100-200MPa. Martian regolith based conconcrete only has 72MPa compressive strength so need to extract the iron out of regolith to make high strength steel that is 700MPa for the bottom section of the tunnel. I am designing a steel silo made of this material that is a cylinder but thickness yet to be determined, with horizontal cross beams rotating along the height of the tunnel like stairs/helix also made of high strength steel to support the sides evenly. The design now looks just like the TV series silo with the helix stairways! Coincidence?

UPDATE: Chat GBT thinks it will be 326MPa not 600MPa. So its about 3 X the preassure Challenger Deep delt with in the deepest Ocean point on Earth (Mariana Trench) that is 110MPa. Did you factor in Martian gravity?

ORIGINAL REPLY:

Don't forget Mars has less gravity. Have you factored in Martian gravity when calculating the compressive pressure? Regardless remember we are talking about building a silo which replaces the excavated dirt and it will act to prevent the colapse with horizontal stabalization. The design of the Silo is something that needs to be discussed. So far this is just the basic idea.

On Earth we have reached 12km with a small narrow hole so if you're right it's just a matter of doubling the results in Kolar Peninsula and scaling up the diameter. I am thinking a nuclear powered massive drill bit built into the silo that can be lowered and raised electrically and have huge RPM from the nuclear reactor.

We could also consider preassurizing the tunnel with 1 bar or above to compensate for the 600MPa you quoted. Thanks for this work by the way forces me to consider this variable! 600MPa is 6,000 bars. So if we preassurize it with gas from Martian atmosphere/ice it would not be habitable while we drill until some solid re-enforcements are built around the circumference with a good pylon design.

Welcome any suggestions for the silo design! Im not a structural engineer!

Recent Update:
Latest Simulation shows more like 5-10 tons to LEO because we need the deorbit burn to return to Earth.

https://photonbytes.com/2025/01/22/500k … rporation/

Hi all, didn't realize there was a spaceplane topic. It's been a while since I was in this forum. We at The Space Plane Corporation
space-plane.org have just made a breakthrough in simulation trials. In theory we have cracked the code for single stage to orbit using a combined cycle air breathing rocket engine.

Summary
MTOW: 250 metric tons
Chassis: 60-75 tons (24-30% mass fraction)
Total Mass to LEO: 87 metric tons
Useful Payload to LEO: 12-27 metric tons

Explanation: Using an airbreathing rocket technology with scramjet and ODWE(Oblique detonation wave engine) "Schramjet/Sustained Combustion Ramjet." we had to use phugoide oscillations to our advantage by switching to minimum AOA drag profile on the downside to pick up speed and then switch to max Lift Drag Ratio AOA settings for the autopilot on the upside. To minimized massflow rate further we give the space-plane a sustained Mach3 flight with a high angle of attack because the massflow rate is minimum at mach 3. This way we pick up potential energy by gaining altitude before the above mention phugoid oscillations to pick up speed. Basicly converting potential to kinetic energy constantly but efficiently.

We got 87 tons to orbit, and on a 2nd attempt 86 tons. If the space-plane material absent of fuel and payload is 60 tons this gives it higher payload capabilities but with a mass fraction of 24% (dividing 60/250MTOW:Maximum Take Off Weight). To be more conservative we might want to make the plane heavier with more material and structural integrity, so 75 tons can be an option to boost that mass fraction to 30% but this reduces payload to 12 metric tons.

This is still a win because unlike Starship our design is single stage. No seperate bits falling off. We can take off and land on any long enough runway. And non astronauts can fly because you dont have to be super fit to survive a vertical rocket launch that might blow up at full thrust on the pad. We can provide a comfortable gradual climb from horizontal take off like a normal passenger plane. With economies to scale this will definitely be cheaper as its more efficient compared to Starship. This means that Starship's usage in future should be primarilly non human payload and only trained astronauts while we catch up to the economies of scale to even replace that market.

Video and telemetry documentation here:
https://photonbytes.com/2024/12/20/the- … simulated/

David Ong
space-plane.org
photonbytes.com

It's actually not a bad idea, here's why: Venus has a very very thick atmosphere meaning that you can float at about 20-40km. Launching from such a high altitude with a rocket means the rocket can be smaller. You can float higher up in Venus with smaller balloons.

But back to the topic of balloon on Mars. For the last 3 days I have been grinding away on spreadsheet, AI and google. Here is what I found out. We can use balloon on Mars for large payloads but they have to resemble a wide shape such as a short cylinder of a wide oblique. The reason is because we have to minimize the vertical pressure gradient that forces us to thicken the skin of the balloon as Calliban correctly pointed out. Yes we can put limits on climb rate on sphere shape airships but there is another very compelling reason to go wider with a ratio of 5 to 1 for iexample 280m height cylinder/oblique with 800m radius. The reason is we can join the top and the base with structural beams that will further reenforce the integrity like a honeycomb. And this also optimizes human condition for walking around a flat surface with maximum real estate. With 0.18mm carbon fiber skin(obviously not the bit where we walk on which will be thicker and counted as useful payload) the ballon can lift 100 tons of useful payload to the tip of Olympus Mons. 7000 tons at datum and 15,000 tons at Hellas planitia. Now the internal pressure at Hellas must be 10% higher than the external pressure for redundant structural integrity, 15% higher at datum and 25% higher at 20km(Mount Olympus).

Altitude (km)    External Pressure (Pa)    Internal Pressure (Pa)    Percentage Higher (%)    Pressure Differential (Pa)
20    40    50    25    10
0    610    702    15    92
-8    1,200    1,320    10    120

Yes I know this is a giant flying saucer, but it's only giant because it is designed for all ground levels of Mars incluing Olympus Mons. We can get away with much smaller 250m radius cylinders with about 60m height for performance below the volcano but above datum.

UPDATE: I think oblique is better or a cylinder with rounded edges. But I prefer oblique because its more aerodynamic all around. With cylinder there might be too much stress on the top or bottom because it's perfectly flat and will hit head on to airflow generating stress.

I think ID4 and V got it right!

First of all I want to thank everyone especially Calliban for getting me a head start on the design process and getting me educated on the structural aspects of a balloon which is valid.

But even after all the structural considerations please realize that Mars as less gravity as a smaller planet that actually in signficant ways compensates almost completely perhaps exceeds the advantage of balloons on Earth too.

Your most recent chart only goes up to 25 meters and shows a illustration of such a balloon size.

However if you will refer right back to the chart I sent you before you will see that with the reduce Martian gravity when you go above 160m radius you get back some significant gains. I would encourage you to extend your chart all the way to 200 meters radius and rerender your AI inspired illustration to show what the new balloon would look like at that scale. The only disadvantage with Mars is the minimum radius. Once you go pass 160m radius you can catch up to Earth abilities. Lift force too strong for balloon structural integrity? No problem, what you then do is set limits for the descend and ascent (climb rate) rate. Have a no exceed limit for climb. Then the extra mass needed for internal skeleton is much reduced and you still have your exponential gain.

Remember a larger balloons means higher altitude of lift and higher force of lift but we can control the lift force but controlling how much hydrogen is in the bags. We can carefully keep the amount of gas controlled so the balloon radius is in practice less than what it physically is.

M A R S  H A S   L E S S  G R A V I T Y = Scale Height is elongated meaning also the max altitude is much higher than that on Earth because the air density changes are likewise stretched farther out into space. Because Mar's scale height is 11km vs Earth's 8km Mars atmospheric layer is actually thicker but the air density is not. Mar's atmosphere reaches farther out into space, this is true, while Earth's atmosphere is "thinner" it's denser. This is a tricky play on symatics that you might not be normally familiar with for Mars because the of media portrayal.

Below: Factoring in balloon mass which looks like it has a linear relationship after a certain point on the cart still gives no significant problems when you go to 200m, here after subtracting balloon mass you still have 385 tons of useful payload. I would design the balloon so that both structure and cabin spaces are integrated into the balloon material for further optimizations and to strengthen the skin, more of this integration into the balloon skin would be at the bottom to keep the ship/balloon (their both the same in this scenario - look at my picture) upright. Keep more mass on the bottom.

Pros and Cons of Martian Airships:

Cons:

1. Rise and Fall of airship is going to be limited due to weak Martian Gravity which actually cancels out the problem of structural integrity brought up by Calliban. However because of limited climb speed control of the airship wont be as great vertically compared to Earth airships which can climb and fall much quicker. However we can compensate with propulsion systems such as high RPM rotors or better still ion wind systems - ionowind propulsion. This works better on Mars due to laminar nature of atmosphere.

2. Ship has to be at least 160m in radius.

Pros:

1. Mars has low gravity cancelling out the low density atmosphere problem to a significant extent.

2. Mars has large scale height of 11km vs 8km of Earth. Enabling higher possible altitudes since the drop in air density is not as fast as that on Earth as you rise.

3. Because of low Martian Gravity Structual integrity issue brought up by Calliban is less of an issue. The balloon climb rate is going to be weaker and the disadvantages outlined in part 1 of cons.

UPDATE: Also NASA is doing this, here is an updated graphics that will cheer up Calliban as now he is included in it with association with NASA
https://www.everand.com/article/5624454 … n-Airships
https://www.spaceanswers.com/futuretech … pacecraft/

Ok because you cannot scroll up this image I'll explain what was discussed with AI before the screenshot.
Basicly when you double the radius you 8 times the volume, 4 times the surface area and you 2 times the balloon material to compensate completely for the increased forces experienced. However 2 times the material mass is only a fraction of the 8 times in lifting ability. And that fraction reduces each time you double the radius!

Btw, thanks for bringing this up and not giving up trying to call me out, because of this it got me thinking about this ahead of schedule and I didn't actually know about the doubling of material as a compensation which is something I was eventually going to tackle and find out anyways but thanks for speeding up the process of me designing an interstella Airship. It will probably be saucer shaped not spherical and most of the payload will be part of the enclosing material discussed to further enhance the ability of the ship to handle stress. The flying saucer is going to have most of its mass as part of it's outer protective shell - This is a potential future post "Interstellar HAPs"