Balloon (balloons) on Mars - Facts vs Fantastic vision

SpaceNut · 2024-05-20 16:51:18

Fantasy not as Yes, a helium balloon can certainly work on Mars. There have been many studies at NASA's Jet Propulsion Laboratory and NASA's Wallops Flight Facility that show feasible mission designs.

Since we have high air balloons on Earth then the ability of Mars lift effectiveness of balloon is more than 100 times less on mars.

MARSBalloon 2024

Mars, a hydrogen filled interior, a balloon density of 1250 kg/m 3 and a thickness of 0.00005 meters, a series of calculations were performed to estimate the lift potential

A mars balloon might appear like this

https://www.gaerospace.com/space-explor … -balloons/

https://www-robotics.jpl.nasa.gov/what- … -balloons/

tahanson43206 · 2024-05-20 18:13:45

For SpaceNut re #26

Thank you for finding and posting the links and images from the study of balloons for Mars flight.

I was delighted to see that the graph of lift vs radius was very close to the one that ChatGPT4o generated in Post #18.

The graphs differ in orientation, but the curves are very similar, which is not surprising to me, but I am ** glad ** to see it!

The graphs differ slightly. I compared the mass density of the envelope material, and the thickness, and they differ slightly, so it should not be surprising that the curves differ slightly.

To be specific, the density is less in the study you found, but the thickness of the envelope is greater.

I can run the ChatGPT4o Python program with the starting figures shown in the study you found, and we can compare the curves. I expect they would become even more similar, but we need to run the Python program with the new values to find out.

Both programs show that after the initial hurdle of negative lift, lift increases slowly but steadily with increased volume. The practical limit is the size of the envelope that might be manufactured by human beings alive in the Universe any time soon.

I'll post the #18 image here so our readers/members can compare them easily.

Please note that the two plots coincide at 20 meters radius by showing 200 kilograms payload.
Remember that a Newton is about 1/10th of a kilogram. Get the exact figure from Google.

Plot of Balloon Lift in Newtons vs Radius in meters

(th)

tahanson43206 · 2024-05-20 18:57:57

For SpaceNut ... I am back from running the Python program with the parameters used by the study you found. The curve looks almost identical.

I conclude that my methodology appears to stand up to at least preliminary review as compared to an independent reference.

I'll post the image and the revised program shortly.

# debugging commented or removed
# Balloon Lift vs. Radius 2024/05/20 Revised from 1390 and 000012
import numpy as np
import matplotlib.pyplot as plt
# Constants
density_mylar = 1250 # kg/m³ revised from 1390
thickness_mylar = 0.00005 # meters was (12 micrometers)
gravity_mars = 3.71 # m/s²
molar_mass_hydrogen = 0.002 # kg/mol
molar_mass_co2 = 0.044 # kg/mol
R = 8.314 # J/(mol·K)
pressure_mars = 610 # Pa
temperature_mars = 273.15 # K
density_co2 = 0.0198 # kg/m³ on Mars
newton_to_gram_force = 101.97 # Conversion factor
def calculate_volume(n_moles):
# Calculate volume of hydrogen gas
volume_hydrogen = (n_moles * R * temperature_mars) / pressure_mars
return volume_hydrogen
def calculate_radius(n_moles):
# Calculate volume of hydrogen gas
volume_hydrogen = calculate_volume(n_moles)
# Calculate radius of the balloon
radius = (3 * volume_hydrogen / (4 * np.pi)) ** (1/3)
return radius
def calculate_lift(n_moles):
# Calculate volume of hydrogen gas
volume_hydrogen = calculate_volume(n_moles)
# Calculate radius of the balloon
radius = calculate_radius(n_moles)
# Calculate mass of the Mylar envelope
surface_area = 4 * np.pi * radius**2
mass_envelope = surface_area * thickness_mylar * density_mylar
weight_envelope_mars = mass_envelope * gravity_mars
# Calculate the lift force provided by the hydrogen gas
lift_force = (volume_hydrogen * density_co2 * gravity_mars) - (n_moles * molar_mass_hydrogen * gravity_mars)
# Calculate net lift force by subtracting the weight of the envelope
net_lift_force = lift_force - weight_envelope_mars
return net_lift_force, radius, mass_envelope
# Generate data for the plot
moles_range = np.arange(1, 10000) # Start from 1 mole
# Calculate lift, radius, and mass for each mole count
lift_data = []
radius_data = []
mass_envelope_data = []
for moles in moles_range:
lift, radius, mass_envelope = calculate_lift(moles)
lift_data.append(lift)
radius_data.append(radius)
mass_envelope_data.append(mass_envelope)
# Plot the data
plt.plot(lift_data, radius_data)
plt.xlabel('Lift (N)')
plt.ylabel('Radius (m)')
plt.title('Balloon Lift vs. Radius 1250-5')
plt.grid(True)
plt.show()

Image link here:

Compare the plot using the values from the study that SpaceNut found. To my eye, they look very close.

(th)

tahanson43206 · 2024-05-20 19:40:55

For those who might wish to evaluate various materials and thicknesses for the envelopes of your balloon science package at Mars, just change the parameters for those two parameters in the python program posted above, and run the plot.

The thicker the plastic (or metal?) you are using, I would expect the more durable your envelope will be, at the price of reduced payload.

Likewise for density, which I assume may be directly related to toughness (but I don't have anything to go on except intuition).

In another topic, a member has proposed using metal for the envelope. That can be tested with the Python program .... the density can be entered and the thickness chosen, and the program appears able to reliably compute the lift vs radius.

It would certainly be helpful for readers of this topic if someone were to provide example plots for various materials to see how they perform.

The metal walled balloon that we've seen proposed would need great size to lift off, but it would (presumably) be more durable than plastic.

(th)

tahanson43206 · 2024-05-21 06:29:28

In another topic, PhotonBytes has asked a pertinent question....

How does the force of gravity change with respect to air pressure with altitude above the surface of Mars?

The decrease in the force of gravity is likely to follow a consistent pattern, while air pressure is likely to be less consistent since the atmosphere is a moving mass of gas subject to changes in illumination from the Sun and other factors.

There is an opportunity for a NewMars member to contribute factual data to this topic, to help to put the question into perspective.

My guess is that the force of gravity of Mars in the regime where the atmosphere would support balloon flight will change only slightly, while the air density will fall off rapidly with distance above the surface.

The ceiling for operation of a balloon should become clear, as the density of the atmosphere decreases with elevation.

(th)

tahanson43206 · 2024-05-21 07:00:25

As this topic is set up to hold practical information as well as factual information, I'd hoping we might have one or two members who can address the question of how to fabricate a balloon for service on Mars.

Mylar is an example of a lightweight material that can hold hydrogen reasonably well, but it comes from the manufacturer in sheets that must be assembled into a spherical or similar shape to hold the gas. The challenge for anyone wanting to make a balloon, or Earth or Mars or anywhere, is how to assemble the envelope of the balloon so it is intact over the entire surface.

We have members who have visions of metal walls for balloons on Mars. There are aluminum walled balloons available for decoration at public events, available for sale on the Internet, so it is clear that it is possible to create an inflatable balloon structure on Earth, using aluminum. That balloon is not intended for flight, but the fabrication technique used would (presumably) work for a version of such a balloon intended for flight.

If a member has the time and interest to investigate how balloons are made from sheets of material, that would be a welcome addition to this facts oriented topic.

How force is transferred from the walls of the balloon to the payload is also a question whose solution would be a welcome addition to this topic.

Fishnet enclosure is reported to be an option that would allow the envelope to have to deal only with the important job of holding hydrogen.

(th)

tahanson43206 · 2024-05-21 07:53:57

A balloon is a fragile device wherever deployed.

This topic is a good place for NewMars members to tackle the practical question of how to protect a balloon envelope from tearing due to contact with a sharp object on the ground, such as a rock on the surface of Mars, or an antenna on a Mars rover that might be in the path of a low flying balloon.

On Earth a time honored technique for increasing the reliability of a lighter than air craft is to employ large numbers of smaller balloons held inside a much larger envelope. However, we have seen that the lift capability of a balloon on Mars is constrained by the mass of the envelope, so the tendency of a balloon designer for Mars would be to increase the envelope as much as possible. However, a tear anywhere in the envelope of a large balloon would result in unplanned descent of the entire balloon.

Measures designed to prevent or restrict tearing will add mass.

This is an interesting design problem for our more adventurous members to tackle.

(th)

GW Johnson · 2024-05-21 10:57:59

I do not understand where the molar volume figures into the lift of a balloon, which is what I think I see in the Python code listing in post 28 above. More than half a century ago in high school chemistry I was taught that 1 gram mole of any gaseous substance occupied 22.4 liters of volume, but I was ALSO taught at that time that this was only a rough approximation: the actual volumes varied some, from substance to substance.

What molar volume might have to do with actual balloon volume seems rather remote, at best. Well-accepted, centuries-old geometry formulas are the way to estimate balloon volumes, which have absolutely nothing to do with chemistry in any way. Assuming spherical shape, the volume of a sphere is V = (4/3) pi R^3, and the surface area of a sphere is S = 4 pi R^2. Radius R is half the balloon's diameter, which is what most folks are used to seeing. The only approximation would be the volume of the balloon envelope material as Ve = S t, where t is its thickness. But it is a very close approximation indeed, for such thin material.

The weight on Mars of a balloon envelope depends on its size as measured by diameter. It is (mass density of material)* (Mars acceleration of gravity)*(volume of envelope material Ve). Similarly, the weight of the lifting gas contained within the balloon is Wgas = (mass density of gas)*(Mars gravity acceleration)*(volume of the balloon V). Also similarly, the weight of Mars atmosphere that could be contained within the balloon is Watm = (mass density of atm)*(gravity acceleration)*(volume of balloon V). Physics says (and has for well over a century) that the buoyancy force acting on the balloon is the Watm - Wgas weight difference of the possible contained species. A free-body diagram of all the forces acting on the balloon reveals its net load capacity to be its buoyancy force minus its envelope weight. All of these things are easily calculable versus a spread of diameters to make a plot of trends with size.

As for related physics, we are NOT assuming any excess internal inflation pressure, so the pressure inside the balloon is the same as the atmospheric pressure outside it. If in thermal equilibrium, the temperature inside the balloon is the same as the atmosphere outside; but if you are looking at the "hot air balloon" concept, heating makes it higher inside.

The only chemistry (and it's really just physics) here is using the ideal gas equation to estimate atmosphere and gas mass densities. That would be mass density = (atm pressure) (species molecular weight) / [(universal gas constant)*(absolute temperature)]. If you are worried about condensation, the universal Z chart gives you Z for the modified ideal gas equation rho = P MW Z / (R T).

That's just about as simple and straightforward as it is possible to get. Why is there debate about this?

GW

Last edited by GW Johnson (2024-05-21 11:00:54)

tahanson43206 · 2024-05-21 11:34:09

For GW Johnson!

Thanks (as always) for helping with all topics, and this one in particular.

ChatGPT4 computed a volume for a mole of hydrogen gas on Mars, at the surface, and 273 degrees Kelvin.

The figure differs from the 22.4 liters you remembered, so we need to clarify that right away.

By any chance, are you remembering the volume of a liquid? That would certainly seem to make sense.

Here is what ChatGPT4 reported:

Summary:
The volume of one mole of hydrogen gas at the mean surface pressure of Mars (610 Pa) and a temperature of 0 degrees Celsius (273.15 K) is approximately 3.72 cubic meters.

You can see the entire analysis laid out in excruciating detail in a post earlier in this topic.

I'll look for the post number and return shortly.

https://newmars.com/forums/viewtopic.ph … 54#p223254

Let's take this a step at a time. ChatGPT4 can make mistakes and when it does so, i want to know about it and make the required corrections.

As a reminder... ChatGPT4's Python program produced exactly the same graph as was produced for a study that SpaceNut found, done by an academic.

As a further reminder, a completely different AI program computed the same situation and gave exactly the same result: 3.72 cubic meters.

(th)

tahanson43206 · 2024-05-21 11:53:42

For all ... It is an honor to be able to provide communication between the human members of the NewMars forum, and one of the more advanced AI's on Planet Earth. In this exchange, I was hoping ChatGPT4 might be able to figure out where 22.4 liters might be coming from.

Here is the explanation:

Clarification on Volume of a Mole of Gas
The value of 22.4 liters:
- This is a well-known reference in chemistry.
- It represents the molar volume of an ideal gas at standard temperature and pressure (STP).
- STP is defined as a temperature of 0°C (273.15 K) and a pressure of 1 atmosphere (101.325 kPa).
To clarify the difference:
**22.4 liters**: This is the volume occupied by one mole of an ideal gas at STP (0°C and 1 atm).
**2.73 cubic meters (or 2730 liters)**: This is the volume of one mole of hydrogen gas under the conditions present on the surface of Mars, which are very different from STP. Mars has a much lower atmospheric pressure and a different temperature.
Calculations:
1. At STP (Earth):
- One mole of an ideal gas occupies 22.4 liters.
2. On Mars:
- Surface temperature on Mars: approximately -60°C to 0°C (average around -60°C or 213.15 K).
- Surface pressure on Mars: approximately 610 Pa (0.006 atm).
Using the ideal gas law, we can calculate the volume of one mole of hydrogen gas on Mars:
\[ PV = nRT \]
\[ V = \frac{nRT}{P} \]
Given:
- \( n = 1 \) mole
- \( R = 8.314 \, \text{J/(mol·K)} \)
- \( T \approx 213.15 \, \text{K} \) (assuming -60°C)
- \( P = 610 \, \text{Pa} \)
Calculating the volume:
\[ V = \frac{1 \times 8.314 \times 213.15}{610} \approx \frac{1771.9821}{610} \approx 2.905 \, \text{m}^3 \]
This aligns closely with our previous calculation of approximately 2.73 m³. The slight difference might be due to different temperature assumptions or rounding.
Summary:
**22.4 liters** is the volume at STP (Earth conditions).
**2.73 m³** (or around 2730 liters) is the volume at Mars conditions due to much lower pressure and temperature.
This large difference in volume is due to the significantly lower pressure on Mars compared to Earth's standard atmospheric pressure.

(th)

tahanson43206 · 2024-05-21 11:59:34

Occasionally ChatGPT puts latex formatting (for printers) into tt's responses. I asked it to try again, and this version seems slightly better...

Clarification on Volume of a Mole of Gas
The value of 22.4 liters:
- This is a well-known reference in chemistry.
- It represents the molar volume of an ideal gas at standard temperature and pressure (STP).
- STP is defined as a temperature of 0°C (273.15 K) and a pressure of 1 atmosphere (101.325 kPa).
To clarify the difference:
22.4 liters: This is the volume occupied by one mole of an ideal gas at STP (0°C and 1 atm).
2.73 cubic meters (or 2730 liters): This is the volume of one mole of hydrogen gas under the conditions present on the surface of Mars, which are very different from STP. Mars has a much lower atmospheric pressure and a different temperature.
Calculations:
1. At STP (Earth):
- One mole of an ideal gas occupies 22.4 liters.
2. On Mars:
- Surface temperature on Mars: approximately -60°C to 0°C (average around -60°C or 213.15 K).
- Surface pressure on Mars: approximately 610 Pa (0.006 atm).
Using the ideal gas law, we can calculate the volume of one mole of hydrogen gas on Mars:
\[ PV = nRT \]
\[ V = \frac{nRT}{P} \]
Given:
- n = 1 mole
- R = 8.314 J/(mol·K)
- T ≈ 213.15 K (assuming -60°C)
- P = 610 Pa
Calculating the volume:
V = (1 * 8.314 * 213.15) / 610 ≈ (1771.9821) / 610 ≈ 2.905 m³
This aligns closely with our previous calculation of approximately 2.73 m³. The slight difference might be due to different temperature assumptions or rounding.
Summary:
22.4 liters is the volume at STP (Earth conditions).
2.73 m³ (or around 2730 liters) is the volume at Mars conditions due to much lower pressure and temperature.
This large difference in volume is due to the significantly lower pressure on Mars compared to Earth's standard atmospheric pressure.

(th)

tahanson43206 · 2024-05-21 12:25:25

To try for consistency in this topic, I would like to suggest that everyone use the same values for temperature and atmospheric pressure:

[h3]Clarifying Hydrogen Gas Volume on Mars[/h3]
To ensure consistent comparisons, we use the following standard conditions for our calculations:
Temperature: 273 K (0°C)
Pressure: 610 Pa (surface pressure on Mars)
Calculation Steps for Hydrogen Gas Volume on Mars
Given Values:
Number of moles (n): 1
Ideal gas constant (R): 8.314 J/(mol·K)
Temperature (T): 273 K
Pressure (P): 610 Pa
Ideal Gas Law:
PV = nRT
Rearrange for Volume (V):
V = \frac{nRT}{P}
Plug in the Values:
V = \frac{1 \times 8.314 \times 273}{610}
Compute the Volume:
V \approx \frac{2271.42}{610} \approx 3.72 m^3
Summary:
At the specified conditions (273 K and 610 Pa), 1 mole of hydrogen gas on Mars occupies approximately 3.72 cubic meters.
This consistent calculation helps us compare different balloon configurations accurately under the same atmospheric conditions.

(th)

SpaceNut · 2024-05-21 17:30:41

Rounding errors as the H atom measures 1.0008 and it requires 2 such that each molecule is H2 plus you then have a ration of isotopes that are also present. Same thing happens with all measurements as we see for the most part that they are close enough.

update:
Also notice the volume is different as well.

tahanson43206 · 2024-05-21 19:58:16

For SpaceNut re #38

Your point about isotopes (ie, neutrons) present in a gas mixture is interesting.

The team preparing hydrogen for a balloon application on Mars could select molecules of Protium to maximize the lift potential of the gas.

The team would have plenty of time to prepare the hydrogen for the balloon, if we are talking about a scientific exploration package.

I just asked ChatGPT4o to estimate the difference of mass of a mixture of Hydrogen from Earth water, and pure Protium. The difference is on the order of 10 micrograms per mole, which hardly seems worth all the trouble, unless extracting the Deuterium is useful on it's own.

(th)

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#26 2024-05-20 16:51:18

Re: Balloon (balloons) on Mars - Facts vs Fantastic vision

#27 2024-05-20 18:13:45

Re: Balloon (balloons) on Mars - Facts vs Fantastic vision

#28 2024-05-20 18:57:57

Re: Balloon (balloons) on Mars - Facts vs Fantastic vision

#29 2024-05-20 19:40:55

Re: Balloon (balloons) on Mars - Facts vs Fantastic vision

#30 2024-05-21 06:29:28

Re: Balloon (balloons) on Mars - Facts vs Fantastic vision

#31 2024-05-21 07:00:25

Re: Balloon (balloons) on Mars - Facts vs Fantastic vision

#32 2024-05-21 07:53:57

Re: Balloon (balloons) on Mars - Facts vs Fantastic vision

#33 2024-05-21 10:57:59

Re: Balloon (balloons) on Mars - Facts vs Fantastic vision

#34 2024-05-21 11:34:09

Re: Balloon (balloons) on Mars - Facts vs Fantastic vision

#35 2024-05-21 11:53:42

Re: Balloon (balloons) on Mars - Facts vs Fantastic vision

Clarification on Volume of a Mole of Gas

#36 2024-05-21 11:59:34

Re: Balloon (balloons) on Mars - Facts vs Fantastic vision

Clarification on Volume of a Mole of Gas

#37 2024-05-21 12:25:25

Re: Balloon (balloons) on Mars - Facts vs Fantastic vision

#38 2024-05-21 17:30:41

Re: Balloon (balloons) on Mars - Facts vs Fantastic vision

#39 2024-05-21 19:58:16

Re: Balloon (balloons) on Mars - Facts vs Fantastic vision

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