Forty 40 Ton Mars Delivery Mechanism

tahanson43206 · 2024-02-02 07:14:48

This topic is reserved for discussion of a (possible) mechanism for delivery of 40 ton payloads to the surface of Mars from interplanetary transfer vessels on a plain Earth-Return Hohmann Orbit.

Updated 2024/02/07 to include all possible delivery mechanisms, from all possible arrival modes.

Void has reminded us that the Ballistic Capture orbit permits shipment of supplies to Mars at any time.

The tradeoffs include a longer travel time, and a higher parking orbit that is typical for scientific missions.

Updated 2024/02/22 - this topic is available for one-and-done delivery methods, or reusable designs.

Rather than create a separate topic, I'm hoping contributors will clarify which design is the focus of their post(s).

There is a third option ... A one-and-done design can be configured so that the rocket components can be unbolted from the delivery frame, and re-assembled into a rocket system capable of taking off from the surface of the body.

(th)

tahanson43206 · 2024-02-02 07:16:17

This post is reserved for details of a proposal for delivery of 40 tons of payload to the surface of Mars from a vessel on a Hohmann Earth-Return orbit.

This post by GW Johnson sets the stage for direct landing from Hohmann:
https://newmars.com/forums/viewtopic.ph … 76#p219076

(th)

tahanson43206 · 2024-02-02 09:41:09

This post reflects a session with BARD that ended up as a Google Image lookup.

I'm not sure if I can post a link to the image I'd like to show, but here is the citation quote:

Carpentier, Justin & Benallegue, Mehdi & Laumond, Jean-Paul. (2017).
On the centre of mass motion in human walking.
International Journal of Automation and Computing.
14. 1-10. 10.1007/s11633-017-1088-5.
The center of mass (CoM) is a key descriptor in the understanding and the analysis of bipedal locomotion. Some approaches are based on the premise that humans minimize the CoM vertical displacement. Other approaches express walking dynamics through the inverted pendulum model. Such approaches are contradictory in that they lead to two conflicting patterns to express the CoM motion: straight line segments for the first approaches and arcs of a circle for the second ones. In this paper, we show that CoM motion is a trade-off between both patterns.
Specifically, CoM follows a "curtate cycloid", which is the curve described by a point rigidly attached to a wheel rolling on a flat surface. We demonstrate that all the three parameters defining a curtate cycloid only depend on the height of the subjects.

It is the cycloid I would like to show in this topic.

Link to image goes here:

Notes on image: The cycloid of interest for ** this ** topic is the one at the top in the image from the work by Carpentier, Justin & others.

SpaceNut · 2024-02-03 08:16:46

I did see the trace and it's a portrayal of the curve that mars launch vehicle takes to get to mars.
The issue is the window of opportunity to launch that is about a month to 2 wide. At the beginning of the cycle the fuel to get a mass to mars is different to the amount required at its end even for the same payload.

Now payload to surface is not the payload of that unit at launch from earth as it requires much more than that to fuel the vehicle to make it possible to land it on the surface. It will also need to have more if the unit is the habitat for man not only for going, the stay on the surface but for the return as well from many consumable items.

The mass of the lander is above the levels of a dragon and will require it to be larger and would limit the quantity of crew size.

will find the information of that size landing which I know is here already in another topic.

SpaceNut · 2024-02-03 08:37:09

Mars Landing Vehicles: Descent and Ascent Propulsion Design Issues

Future human missions have suggested large 5 to 25 MT surface payloads may be
needed. Therefore, large landing vehicles with an initial mass of up to 100 MT may be required.

Surfacve power support is an important part of that payload to the surfacce as well for the design.

Human Mars Lander Design Drivers and Challenges as its more than just payload as the mass of the lander is also contributing to the landing issues.

Human Mars Lander Design for NASA’s Evolvable Mars Campaign which gets into fuel to land an much more for getting back home.

tahanson43206 · 2024-02-03 12:27:47

For SpaceNut re #5

Thank you for this helpful contribution to a topic about landing 40 tons on Mars.

This topic is set up to cover all possibilities.

Traditional ones are all we humans have available at this point, and your post helps by showing some of them.

In coming days, I am hoping we may discover an additional (non-traditional) landing method.

GW Johnson has already begin to think about the process I've suggested.

Remember, this idea is over 50 years old, and GW Johnson was barely out of high school at the time it was first published. He had a lot on his mind beside landing methods for Mars.

However, we have begun discussion of a full sized Texas style oil rig to drill two shafts a mile down on Mars. That rig is going to weigh many tons, and it will require major advances in lift and landing technology to put it into service.

Traditional chemical landing methods have a place in the planning spectrum. In fact, that is the ** only ** capability that humans have demonstrated on the Moon or Mars. The moon landings require retro-rocket propulsion by default, but Mars provides a bit of wiggle room due to the thin atmosphere.

This topic is available for members to collect links to media that helps us track developments as they occur.

In addition, there is room in this topic for some of Void's ideas (for example). These are often designed to stretch human imagination, and I have no doubt that if Void contributes to ** this ** topic, whatever he posts will be worth reading, and perhaps thinking about.

(th)

tahanson43206 · 2024-02-03 13:35:08

I asked ChatGPT4 to see what it could do with DALL-E, to show delivery of a 40 ton payload to the surface of Mars, using GW Johnson's baton in the hands of a cheer leader. Here is the prompt that Ch4 crafted, along with comments it made.

Innovative Visualization of a Cycloid Path on Mars: A Collaboration with AI
We embarked on a fascinating journey to visualize the concept of delivering a payload to the surface of Mars using a cycloid path, inspired by the motion of a baton. The challenge was to distill this complex idea into a simple yet compelling image that DALL-E could interpret and bring to life.
The result is nothing short of spectacular. The image captures a cheerleader in mid-air, running across a pristine lawn that seamlessly transitions into the reddish terrain of Mars. The cheerleader, dressed in a futuristic, Mars-themed costume, holds a long, slender baton vertically. The baton's tip, a brightly illuminated globe, gently touches the ground, leaving behind a tendril of dust that traces its cycloid path.
The artistic execution by DALL-E, guided by a carefully crafted prompt, illustrates the cheerleader's dynamic motion, with her hair flowing in the wind. The golf-course-quality lawn juxtaposed with the Martian desert and a Mars-like reddish sky creates a vivid, engaging scene. The sun, positioned behind the figure, casts appropriate shadows, adding to the realism and depth of the image.
This collaboration showcases the potential of AI in bringing complex scientific concepts to life in visually stunning ways. It's a testament to the power of creative prompt engineering and the artistic capabilities of AI.
We're delighted to share this groundbreaking work with our international community, demonstrating the innovative intersection of science, art, and technology.

The link to the image goes here:

Note on image: I asked CH4 to ask DALL-E to recreate the image with a cheer leader from another ethnic group, but while the image was created and is impressive in it's own right, it has almost nothing to do with the point, which was to show the payload landing gently on Mars. Let the record show CH4 and I made the attempt.

(th)

tahanson43206 · 2024-02-04 08:21:58

In today's work session, ChatGPT4 and I attempted to persuade DALL-E to show a payload delivery using the cycloid curve. The image that DALL-E came up with shows the instant when the payload touches the surface and is released from the line. ChatGPT4 seems to understand the context of the image. Here is CH4's presentation. I'll add a link to the image below.

Capturing a Pivotal Instant in Mars Payload Delivery: A Panoramic Visualization
In our latest collaborative effort with AI, we've visualized a significant moment in the innovative process of delivering a payload to the surface of Mars. This panoramic image is a testament to human ingenuity in space exploration, illustrating the culmination of meticulous planning and precision engineering.
The scene is divided into three distinct sections:
- The bottom third showcases Mars's rugged surface, where the payload achieves its touch down.
- The middle third captures the planet's thin atmosphere, serving as a transitional layer from space to the surface.
- The top third reveals the vast expanse of space, dotted with celestial objects, underscoring the spacecraft's remote origin.
Prior to the moment depicted, the spacecraft and payload, in a harmonious orbit around Mars, initiated a descent maneuver. The payload, stretched out in front of the spacecraft, received an impulse to begin its descent towards Mars. A fine, bright line connected them, tightening as Mars's gravity pulled the payload downward. Meanwhile, the spacecraft applied precise thrusts to moderate the payload's descent, ensuring a controlled and gentle touchdown.
At the instant captured in this illustration, the payload is released, marking the successful end of its journey. The spacecraft persists in its orbit, while the line, buoyed by the momentum of the descent, returns to orbit. This image encapsulates a complex interplay of gravity, momentum, and precise control, highlighting the ingenuity required for such an interplanetary mission.
This visualization not only conveys the technical precision but also evokes a sense of the monumental effort behind interplanetary delivery. It's designed to inspire and educate, offering a glimpse into the future of space exploration and the potential for human achievement beyond our world.

Image goes here:

The objective of this topic is to deliver 40 tons to the surface of Mars. A demonstration delivery of one kilogram would be useful.

(th)

SpaceNut · 2024-02-04 12:32:08

"baton" motion is A.G. in space the haphazard space x is not for atmospheric entry as the stage can bend due to drag and thrust.

Hohmann transfer orbit or Oberth effect, which requires the spacecraft to burn fuel in order to slow down at the target. A requirement for the spacecraft to carry fuel adds to its cost and complexity.

Ballistic capture is a low energy method for a spacecraft to achieve an orbit around a distant planet or moon with no fuel required to go into orbit. In the ideal case, the transfer is ballistic (requiring zero Delta-v) after launch. In the traditional alternative to ballistic capture, spacecraft would either use a Hohmann transfer.

Aerocapture is an orbital transfer maneuver in which a spacecraft uses aerodynamic drag force from a single pass through a planetary atmosphere to decelerate and achieve orbit insertion. Aerocapture uses a planet's or moon's atmosphere to accomplish a quick, near-propellantless orbit insertion maneuver.

Aerobraking is a spaceflight maneuver that reduces the high point of an elliptical orbit (apoapsis) by flying the vehicle through the atmosphere at the low point of the orbit (periapsis). The resulting drag slows the spacecraft. Aerobraking is used when a spacecraft requires a low orbit after arriving at a body.

Gravitational capture occurs when one object enters a stable orbit around another (typically referring to natural orbits rather than orbit insertion of a spacecraft with an orbital maneuvers).

tahanson43206 · 2024-02-07 08:57:25

In email correspondence with forum members, I came across the idea of adapting the existing Mars Hopper design for landing large payloads.

The suggestion to be reported in this post comes out of consideration of how to put a 40 ton payload safely on the ground, if it is delivered by a traditional cylindrical rocket with the payload mounted on the top.

If such a rocket lands successfully, it will be perched on it's tail, and the payload will be far in the air of Mars.

An alternative is to deliver the payload as the center mass in a cluster of four Mars Hoppers.

This configuration would allow for stable delivery of the payload directly to the surface.

After delivery, the Mars Hoppers could disconnect and become available for other duties.

The most attractive propellant for this situation is CO and O2.

While the Mars Hopper is designed for normal operation using Methane (if I recall the design correctly) I am hoping the vehicle can be fueled with CO and O2 in LMO, and in combination with three other Mars Hoppers, land the payload safely on Mars.

If this scenario is practical, it lends itself to the delivery of dry ice to LMO using a SpinLaunch system, which should be able to deliver significant quantities of dry ice to LMO in a day, assuming normal Mars solar power availability.

That dry ice could be converted to CO and O2 in LMO, cooled and delivered to landers for delivery of heavy payloads.

Update: An attempt to persuade ChatGPT4 to persuade DALL-E to create an image showing a payload landing, with assistance of four Mars Hoppers attached at four corners, was not successful. There are simply too many details to be managed. In two attempts, the basic ideas all showed up, but a lot of extranseous creative "contributions" kept the scene from showing what was needed.

Here are the two prompts that ChatGPT4 tried ... in this case, a human being might be better able to visualize the scene.

First Attempt
"A highly detailed scene on Mars, capturing the moment just before a payload, designed to look like a standard shipping container with a seared heat shield on its bottom from atmospheric entry, is about to land. The container is supported by four small, liquid-fueled rockets, each positioned at the container's corners. These rockets are equipped with three landing legs each for stability and are attached to the payload with strong metal braces. The Martian landscape in the background is barren, with red soil and distant mountains, under a light blue sky. The engineering marvel of retro-propulsion in action, with the rockets firing to slow down the descent, is vividly depicted."
Second Attempt
"Revise the scene on Mars to show the moment just before a payload, resembling a standard shipping container with a seared heat shield on its bottom, is about to land. This time, ensure only four small, liquid-fueled rockets are attached directly to the sides of the container at its corners. These rockets should be equipped with three landing legs each, designed to keep the rockets off the ground when the payload lands flat on its bottom. Remove any engines that were previously depicted around the sides of the container pointing outward. The background should still feature the barren Martian landscape with red soil and distant mountains, under a light blue sky, emphasizing the precision of retro-propulsion for a safe landing."

(th)

GW Johnson · 2024-02-07 10:20:56

A lot of these ideas presume infrastructure in place at Mars, such as surface-orbit taxis, orbital taxis between LMO and some elongated ellipse, space stations or depots, and such. That kind of infrastructure will not be in place at Mars for some time yet to come. Probably a long time.

Why not instead work on landing 40-ton payloads on Mars without any such infrastructure in place? THAT is how you support the building of such infrastructure! And THAT is what I have been thinking about.

I've got a rough-out for a 1-way/1-shot surface lander that delivers 40 tons of cargo. It's somewhere near 80 tons at entry right off a Hohmann trajectory, in a cylindrical shape entering end-on that is about 10 m dia and 20 m long. The landing burn is all it has to do, and it uses MMH-NTO storables. There are no chutes.

Now I need a transfer stage from LEO to the Hohmann transfer. That's easy as an expendable. Making it recoverable and reusable, that's hard. But I'm going to rough one out.

Just thinking out loud, food for thought.

GW

Last edited by GW Johnson (2024-02-07 10:22:17)

tahanson43206 · 2024-02-07 10:25:47

BARD was willing to take a try at showing the image I have in mind...

Here is the prompt it used:

Sure, here is the prompt I used to generate the image:
A highly detailed scene on Mars, capturing the moment just after a 40-ton payload, designed to look like a standard shipping container with a seared heat shield on its bottom from atmospheric entry, has firmly landed on the surface. The container is supported by four much larger, liquid-fueled rockets, each positioned high up at the top corners of the container. These rockets are equipped with three landing legs each for stability and are attached to the payload with strong metal braces. The Martian landscape in the background is barren, with red soil and distant mountains.
I hope this is helpful!

A link to the image goes here:

Update: GW Johnson pointed out the lack of redundancy in the image shown above. The concept could be improved by changing the count of rockets at the corners from one to two. However, the image generation software is currently unable to handle that request. I'll try again after some time passes. In the mean time, human readers can easily visualize two rockets instead of one, as well as the heat shield under the container, that the image software did not show.

(th)

SpaceNut · 2024-02-07 16:44:20

Thanks for the connex box lander. The on orbit mass based on what has land thus far is a 14 multiplier to what is the payload. The other is mean diameter of the carrier ship which is 10 m so that the usable is just about 9 for what we can transport with the height open to tuck the payload size under it.
I am currently on cellphone mode as the monitor is in need of replacing.

This image fits into the companion topic of oldfart1939 for a crew of 17 design to my posts for building blocks to deliver and reuse on mars cargo.

tahanson43206 · 2024-02-07 19:17:47

For SpaceNut re #13

Thank you for noting the shipping container as a model for the 40 ton shipment to Mars. I used the prompt that worked with BARD, and gave it to ChatGPT4 to try with DALL-E. Here is the (slightly modified) prompt used by ChatGPT4:

A highly detailed scene on Mars, capturing the moment just after a 40-ton payload, designed to look like a standard shipping container with a seared heat shield on its bottom from atmospheric entry, has firmly landed on the surface. The container is supported by four much larger, liquid-fueled rockets, each positioned at the four corners of the container. These rockets are equipped with three landing legs each for stability and are attached to the payload with strong metal braces. The Martian landscape in the background is barren, with red soil and distant mountains, under a light blue sky, emphasizing the payload and rockets firmly set in the ground after a successful landing.

The link to the image will go here.

Notes: DALL-E ** never ** does exactly what is requested. It got so much right, I decided to go with this image. The structure under the shipping container was DALL-E's invention. It implies the structure was present before the landing, which was not my intent. However, the BARD version shows the payload settled on the surface.

(th)

tahanson43206 · 2024-02-08 08:58:06

We have a robust competition under way!

GW Johnson has offered to develop a traditional Hohman Transfer direct delivery system to put 40 tons safely on Mars, using chemical rockets and a variety of suitable techniques for dealing with the challenges of that approach.

Simultaneously, I am pursuing the 50 year old Cycloid Delivery option, using 50 years worth of technology advancement to (try to) move the concept from hand waving to engineering practice.

In today's work session with ChatGPT4, we wrestled with the concept, and arrived at what appears to me to be an accommodation that says the concept could actually work at Mars. Here is CH4's summary of today's discussion:

Cycloid Payload Delivery System Concept Assessment
The Cycloid Payload Delivery System represents a novel approach to delivering payloads from orbit to the surface of planetary bodies, such as Mars. This system, characterized by its use of a 100-kilometer cable to control the descent of a 40-ton payload, leverages established physics and engineering principles, scaling them to meet the unique challenges of space-based delivery.
Key Insights:
- The system incorporates dynamic drag modulation through airfoils, allowing for precise control over the descent trajectory and enabling precise landings.
- Material science advancements are essential for developing a cable capable of withstanding the significant tensile loads and environmental stresses encountered during operation.
- The concept's scale and operational environment present unique challenges, yet they are within the realm of current engineering capabilities, pending advancements in materials and control systems.
Technical Considerations:
- Material Engineering: The development of a lightweight, high-strength cable is pivotal. Modern materials such as carbon fiber composites or ultra-high-molecular-weight polyethylene (e.g., Dyneema) could offer solutions.
- Aerodynamics and Control Systems: Advanced computing and control technologies are required to dynamically manage the drag modulation and ensure system stability and precision throughout the descent.
- Safety and Redundancy: Ensuring operational safety, particularly in manned missions or critical supply deliveries, is paramount, necessitating robust design and testing.
Conclusion:
While presenting significant challenges, particularly in scale and the operational environment, the Cycloid Payload Delivery System does not face insurmountable barriers at the conceptual stage. With further research, development, and innovative application of materials and technologies, this concept holds promise for revolutionizing payload delivery to planetary surfaces.
This assessment encourages further exploration and development of the Cycloid Payload Delivery System, emphasizing the need for detailed modeling, simulation, and prototyping to validate the concept and refine its design. The integration of advanced control systems and materials science innovations will be key to realizing this ambitious project.
We are now moving towards developing a Python program to model the system dynamics and calculate the required spacecraft thrust. This step will provide valuable insights into the feasibility and efficiency of the proposed system.
Stay tuned for updates on this exciting journey towards pioneering the future of space-based payload delivery.

The next phase is to develop a Python program to compute the thrust that would be needed at the space craft in orbit to decelerate the payload so it sets gently on the ground at the desired location.

Update: Another term that may apply to this payload delivery system is "skyhook". It appears that term may be larger in scope than the focus of this study.

(th)

GW Johnson · 2024-02-08 11:32:27

Just a question with the 4-poster rocket layout at the corners of a sort of shipping container: what happens if one rocket fails?

I've been clustering multiple engines near-centerline to handle engine-out scenarios, able to maintain thrust, but without generating a large over-turning moment.

BTW, I have a roughed-out design for the direct-entry payload that decelerates aerodynamically, then rocket-brakes to touchdown. Off Hohmann, entry is about 5.2 km/s, not too severe, so that the sides and backside can be bare metal insulated on the backside, the only real heat shield a one-shot ablative on the bottom, dropped off to fire the braking engines at about 7 km altitude (which engines use storables to avoid evaporation and boiloff). It masses about 85 tons at entry, carrying some 40 tons of dead-head cargo inside. (This is unmanned-only.)

I have a successful rough-out for the 1-shot/non-reusable transfer stage that uses LOX-LH2 for departure from LEO, then storables for the two course corrections 4.3 and 8.6 months later, the second of which adjusts the trajectory to graze the atmosphere for a 2 degree-below-local-horizontal entry that ends in a survivable altitude (7 km), even at ballistic coefficient near 850 kg/sq.m!!! Chutes only work below 100 kg/sq.m. This transfer stage also enters and breaks up, but a lot of it will hit the surface. I do not like that risk! (I don't like dropping heat shields, either. Debris impact is a serious risk for whatever/whoever is already there in the landing zone.)

Peak aerobrake kinematic gee on the lander is about 2, with about 2.5 peak kinematic gee (about 3 gees felt) during rocket braking. There is lots of propellant budget for hover and divert around obstacles. The landing pad span is about equal to the cg height, for great rough-field stability. I have yet to size the pads, for soft dry unconsolidated sand.

I do not yet have a rough-out for a recoverable, reusable transfer stage. I tried doing it with LOX-LH2 departure, then the rest with storables, but that turned out to be way beyond the knee in the dV vs Wpropellant curve at storable Isp, at around half a million tons of vehicle. The mission dV is bigger than you think: you have a departure burn at Mars to get back onto the trajectory, two course corrections, and an LEO entry burn.

I will look at all LOX-LH2 propulsion, and if that fails, at NERVA. I'd rather do this as a single stage to keep track of and recover, not two or more, for reasons of practicality. Keeping it on the Hohmann ellipse means Earth is not there when it reaches perihelion. But 3.3 years later after the initial departure, it will be. That's how long the propellants must "keep" to support an entry burn into LEO. That is probably just not feasible with LH2. Maybe LOX, maybe not.

GW

Last edited by GW Johnson (2024-02-08 11:38:15)

Calliban · 2024-02-08 15:25:04

GW, how about white fuming nitric acid and propane? Would ISP be good enough?
https://en.m.wikipedia.org/wiki/Nitric_acid

Vapour pressure of HNO3 is 6.4KPa at 20°C. So this should be space storable. The problem is it is highly corrosive. Even the best stainless steels have a finite life in concentrated HNO3. Its melting point is -42°C. So we could freeze it for long term storage and thaw it out some days before we need to activate propulsion.

Vapour pressure of propane is 850KPa at 21°C. So again, it would appear to be space storable.
https://en.m.wikipedia.org/wiki/Propane

I have a vague memory of alcohol-HNO3 being a hypergolic propellant combination. Is this the case? If so, we could use propanol-HNO3.

Last edited by Calliban (2024-02-08 15:41:41)

tahanson43206 · 2024-02-08 16:27:08

For Calliban re #17

Thanks for the hint about white fuming nitric acid ... I asked Google and this came back:

Generative AI is experimental. Learn more
Here are some guidelines for storing white fuming nitric acid:
Containers
Store in the original container, which should be kept upright and tightly closed. The container should be dry, and made of high-density polyethylene (HDPE), fluorinated plastics, or glass. Avoid storing nitric acid in metal containers, as it can corrode and create hazardous reactions.
Storage area
The storage area should be well-ventilated, well-lit, and away from direct sunlight. It should be located away from direct sunlight and sources of heat.
Location
Store in a cool, dry place. If possible, store nitric acid by itself. If not, it should be stored only with compatible oxidizing acids.
Handling
Handle only in a chemical fume hood. Wear eye protection, leather shoes, and an apron or lab coat.
labproinc.com
Handling and Storage of Nitric Acid - Chemicals and Solvents - Lab Pro Inc
Jul 27, 2023 — Recommended materials include high-density polyethylene (HDPE), fluorinated plastics (e.g., PTFE), and glass. Never store nitric acid in metal containers, as it can corrode and create hazardous reactions. Storage Area: The storage area should be well-ventilated, well-lit, and away from direct sunlight.
ehs.washington.edu
nitric acid safety | ehs
➢ Store in original container. ➢ Keep container upright and tightly closed in acid storage cabinet. ➢ Do not store at or above eye level. ➢ Storage containers must be dry, as nitric acid can react with water or steam to produce heat and toxic, corrosive, and flammable vapors.
essr.umd.edu
Nitric Acid Fact Sheet - ESSR
Nitric acid should be stored by itself, if possible. If not, it should be stored only with compatible oxidizing acids. Storage locations should be located away from direct sunlight and sources of heat. Storage location should be plastic corrosive storage cabinets or metal cabinets coated with anti-corrosion liner.
Sigma-Aldrich
White fuming nitric acid - Sigma-Aldrich
Handle only in a chemical fume hood. Keep tightly closed. Store in a cool, dry place. REFERENCES 1• Eckert, Hl; Forster, B.
Chemistry Stack Exchange
How can I safely handle a concentrated (fuming) nitric acid spill?
Nov 12, 2016 — So storage inside is a bit tricky. A real chem lab would have a vented cabinet. Personal Safety - Eye protection is not just recommended, it is mandatory. You'll also need leather shoes that are full covered, and an apron or lab coat (full sleeves / long pants).
Nitric acid is a strong oxidizing acid and can cause spontaneous fires when in contact with organic materials. It should never be stored with flammable solvents and combustibles such as Acetic Acid.
Should nitric acid be stored separately?
Why is HNO3 stored in colored bottles?
Does nitric acid degrade over time?
Ask a follow up...

What I'm wondering is whether shipping the liquid in plastic ? and transferring it to the tanks before needed might be a way to deal with the material without freezing and thawing?

I suppose glass is a reasonable alternative, but plastic might be more resistant to the rigors of space flight.

(th)

Calliban · 2024-02-08 17:19:42

Plastic lined steel tanks and propellant lines perhaps? So long as the plastic remains above glass transition temperature, it should remain ductile, without cracking.

One saving grace of HNO3 is a relatively high density of 1.51g/cm3. That beats LOX (1.14g/cm3). So propellant tanks can be more compact, which partially compensates for lower ISP. How exactly would we pump concentrated nitric acid? Exposed metal components would not live long. I cannot see it being practical to make turbopumps out of plastic. My guess is that this propellant would need to be pressure fed. That implies more structural weight. Not so bad in vacuum, where engine pressure can be lower.

GW Johnson · 2024-02-08 17:45:44

I got the reusable/recoverable transfer stage to work with LOX-LH2 main propulsion. It has a bit of NTO-MMH storables, for course corrections and ullage. The biggest risk with that approach is evaporation/boiloff losses of certainly the LH2, and maybe the LOX. If this ad not worked, I was going to try LH2 NERVA. Now I do not need to do that.

I made the main propulsion tanks into outer tanks containing 2 header tanks, to make them effectively Dewars, once the outer tank is emptied and vented to vacuum. But this stage sees about 3.5 years in space before it reaches perihelion at the same time Earth gets there, for recovery back into LEO. A tug has to go fetch it, and return it to whatever LEO station might be assembling and sending these shots.

The bottom line is this: my means to put 40 tons of dead-head cargo onto the surface of Mars is technologically feasible on paper, even with a reusable transfer stage. The whole bloody vehicle is under 300 metric tons as assembled in LEO, ready to go. It requires absolutely no infrastructure or facilities or people on Mars to start landing those payload shots!

I REPEAT: NO INFRASTRUCTURE REQUIRED AT ALL!

This is a transport means for cargo shipments direct to the Mars surface from LEO, not for sending people. I will be writing it up soon. I have already drafted a slideshow about it.

GW

Last edited by GW Johnson (2024-02-08 17:50:33)

SpaceNut · 2024-02-11 14:01:59

If you go back to the actual skycrane it has eight engines with 2 for each corner of the unit.

mars-curiosity-msl-spacecraft-and-skycrane-3d-model-obj-3ds-lwo-lw-lws.jpg

So, if we broke down a falcon 9 first stage engines for the corners and gave the ship the typical aeroshell for a Mar's landing one can achieve the goal with the tanks above the engines as throw aways with the cradle.

Once the Connex box has touched down it detaches the cable and flies away.

Connex box need a much better tire system and motors to make it mobile which is a must requirement.

tahanson43206 · 2024-02-11 14:42:05

For SpaceNut re Skycrane design...

Thanks for bringing that design back into view...

It would solve the problem that GW is facing, of how to put payload on the ground.

We haven't seen drawings of his design, so we have to wait to see what he's planning.

It would be ideal for the landing vehicle to survive to run another day.

The Skycrane was a One-and-Done design.

GW's design (as I understand it) is to be capable of reuse, but I'm not clear on that point.

If the Skycrane is built larger so that it can hold a full sized container, then the eight engines should be enough to meet GW's observation that the system is vulnerable to failure if there is only one rocket at each corner.

(th)

tahanson43206 · 2024-02-11 15:56:59

I asked Google to find discussion of Skycranes, and there was a ** lot ** to choose from...

Here is a link to an image someone created...

index.php?PHPSESSID=mg74p9h7eeudqpedtv2ci9o17q&action=dlattach;topic=48920.0;attach=1580176;image

The above link may not work. Surprise! It ** did ** work ... However, the idea shown would not work! Still! It ** is ** a vision of a skycrane.

The ** real ** NASA Skycrane supported the payload with a cable/tether. A larger version of that design could deliver 40 tons to any body.

(th)

SpaceNut · 2024-02-11 17:47:15

Actually, Mars rovers, Curiosity and Perseverance used the skycrane. The heat shield for Mars Science Laboratory, with a diameter of 4.5 meters.

The most common type has a 295-cu. ft. capacity, is about 8½ by 6 by 7 ft, and can carry 9,000 lbs.

Conex Box Dimensions: How Wide is a Shipping Container?

of course the connex box mass is counted against the payload.

Standar steel storage containers

tahanson43206 · 2024-02-14 20:54:21

Here is GW Johnson's entry in the 40 Ton Sweepstakes!

https://www.dropbox.com/scl/fi/4s1mq7e5 … 88gfs&dl=0

The paper is detailed, with plenty of diagrams and illustrations, along with text explaining the design trades.

GW's design does NOT put the payload on the soil.

This design DOES require human or Optimus type robots to unload the payload.

It has the distinct advantage of being likely to work on the first try.

(th)

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Forty 40 Ton Mars Delivery Mechanism

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