An Ex Rocket Man's Take On It: July 2025

Trump has vehemently resisted releasing the Epstein files, which his cult supporters believed had a client list containing many names of their political opponents. He has insulted those cult supporters who wanted those files, and he has lied egregiously about this issue (something verified) multiple times.

There may, or may not be, any sort of “client list” in those legal files. If there is, it may or may not have been compiled by Epstein or his people; it might well have been compiled by the government lawyers. There are photos documenting that Trump was once a close friend and frequent visitor to Epstein’s haunts.

One such is shown here, and it is not a fake or an AI construct, but it is a real Getty image. It shows Trump with Melania before they were married, with Epstein (deceased in jail during Trump’s first term), and Ghislane Maxwell (Epstein’s girl friend now serving a prison sentence for sex trafficking).

Why was Trump so desperate not to reveal the Epstein files? All I can say is what I believe, without a public admission or (so far) any proof. In a word, Trump is on that “client list”, however it was compiled and whoever compiled it. He is on the “client list” of a convicted sex trafficker, including the trafficking of underage girls. He did not want you to know that!

You Trump cult believers can add that character fault to all the other verified character faults this man has.

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search code 18072025, search keywords bad government, idiocy in politics

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Update 7-29-2025: my wife found this on her Facebook. It is both too funny and too true, and fits right in with the original article here. It essentially summarizes succinctly and accurately all the bluster coming from Trump's mouth about this issue.

search code 08072025; search keywords space program, spacesuit

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The following is an evaluation of oxygenation issues for space habitations and oxygen suits, without using any models for in-lung oxygen partial pressure. Only what is in the breathing gas to be inhaled is considered here! That way, the issue is not clouded with the effects of breathing gas displacement by in-lung water vapor, or by in-lung carbon dioxide, or by in-lung dead-end volume effects. Not everyone agrees on the efficacy of those models.

Shown in Figure 1 is a list of selected air pressures versus altitude from a US 1962 Standard Day atmosphere model, which is identical to the ICAO Standard Day model up to about 65,000 feet. The breathing gas to be inhaled is either Earthly air at 20.9 volume percent oxygen, or 100% oxygen in a vented face mask, with delivery at the altitude’s pressure. The corresponding oxygen partial pressures were computed and included, along with a description of the circumstances, and an indication of the duration of the exposure.

Figure 1 – Oxygenation Limits Short and Long Term

Partial pressure of oxygen is important, because it is related to the partial pressure of oxygen in-lung. The difference between in-lung partial pressure and that in the blood, is what drives the diffusion of oxygen across the lung membranes into the blood.

The duration of the exposure is very important to determining what levels of oxygen partial pressure are suitable. What I tried to identify as short-term criteria relate to the military and civil altitude requirements for going on oxygen in unpressurized airplane cockpits. Use of such oxygen can be for many hours exposure, and it makes sure the pilots are fully cognitive, up to the upper altitude limits for such vented masks.

Those upper altitude limits for vented oxygen face masks are “fuzzy”. Different people quote different values, usually close to 40,000 or 45,000 feet. Below that upper altitude “limit”, you are “good” for hours. Above it, exposure time with high cognition is limited to only minutes or even seconds. These are typically very short zoom-climb experiences, peaking at 50-some thousand feet altitude. One needs a pressure suit to stay up there.

For long-term criteria, the experiences of populations living at high elevations are very informative. There are two things known that are relevant: chronic hypoxia effects that manifest as “chronic mountain sickness”, and an increase in pregnancy and birthing difficulties above the low-elevation rates, presumably also due to chronic hypoxia. Both start above around 2500 m elevation, and get worse as elevation increases. Below 2500 m, there seem to be no detectable chronic mountain sickness symptoms, and the rates of difficulties with pregnancy and birthing seem indistinguishable from those at sea level.

Maximum oxygen partial pressures are limited by enhanced fire dangers above 21 volume percent near sea level, and seem to be “OK” up to about 0.83 atm partial pressure for several hours flight time, using the Navy criterion for going on oxygen at 5000 feet. The ultimate “fatal exposure” limit (1+ atm) derives from experiences with oxygen in diving.

All of these things are shown in the figure, and highlighted in different colors. The overall conclusions I drew from this are in a small table at the bottom of the figure. I chose partial pressure limits for long-term exposure suitable for habitations, and short-term exposure limits suitable for hours-long work shifts in pure oxygen space suits. The space suit criteria further divide into full cognition, versus mere survival (with presumed cognitive impairment if longer than a few minutes).

Turning to the space suit issue, Figure 2 shows the suit pressures in a variety of units of measure, corresponding to the oxygen partial pressure criteria already identified above, and also as corrected upward to compensate for a 10% pressure leak-down during a long shift. These would obtain, if there were no other effects to consider, but there are!

Experience also shows that breathing oxygen at low pressures causes a loss of water from the tissues in the lungs and respiratory tract. This drying-out of tissues can cause bleeding, which is a very serious problem indeed!

That same experience suggests that there is a minimum suit pressure below which there is a tissue-drying problem, and above which there is no problem. This is a bit “fuzzy”, but the value most quoted is 3.00 psia (corresponding to 0.2041 atm). This is the value to which the 10% leak-down factor needs to be applied for a higher design suit pressure, in order to avoid tissue dry-out during a long work shift, even with leakage.

The result is the final table at the bottom of the figure, showing the “min suit design” pressure, the 10% leak-down pressure for long work shifts, and the short term survival criteria with full cognition, and with impaired cognition, after only minutes.

Figure 2 – Oxygenation Issues for Pure Oxygen Space Suits

Returning to the two-gas mixture habitat atmosphere issue, we have a good minimum partial pressure criterion for very long-term exposures: near 0.15 atm, per the discussion above. However, there are three other things to worry about when setting the habitat breathing gas mixture, presumed to be oxygen and nitrogen. These are: (1) a pressure leak-down over time, to be compensated when detected, (2) the enhanced fire danger of higher percentage oxygen, but which is offset by lower total pressures, and (3) avoiding pre-breathe time, if possible, when going from the two-gas mix to the pure oxygen suit.

I picked the partial pressure of oxygen in the standard atmosphere table at 8200 feet (2500 m) as the “exact” long-term criterion. That partial pressure of 0.1551 atm is indicated in the first calculation with green highlighting, near the top of Figure 3. Just below it, I ran the compositions of air as it was known in the 1960’s, air as it is today with increased carbon dioxide, and a synthetic air (2-gas mix) at the same oxygen content as today’s air. This includes evaluations of molecular weight, gas constant, densities at 1 atm and 59 F (15 C) and also at 1 atm and “room temperature” 77 F (25 C).

From those densities and the mass fraction of oxygen, I computed the oxygen concentrations in kg/m³, at 1 atm and 77 F (25 C) as “room temperature air at sea level”. That value is 0.2738 kg/m³. That would be the max oxygen concentration allowable in the habitat breathing gas, to keep the fire danger as no more hazardous than that of “room temperature sea level air”. It is based on an overall Arrhenius reaction rate model.

I also checked the oxygen concentration of 40% hospital oxygen at sea level and room temperature, known to be a severe fire hazard. It is about twice the concentration of oxygen in ordinary air at sea level and room temperature. That is near the bottom of the figure, result highlighted in blue. One would expect those fires to propagate twice as fast.

The habitat atmosphere calculations start with design values for gas composition and total pressure, and include a leaked-down set of values. These are on the right of the figure, with much blue highlighting, and user inputs highlighted yellow. Based on prior work, I chose to investigate what I call a “rule of 43” 2-gas mix atmosphere of oxygen and nitrogen. The oxygen is 43 volume percent of the mix (leaving 57% nitrogen), and the total pressure is 43% of 1 standard atmosphere. The resulting oxygen partial pressure (0.1849 atm) exceeds the criterion 0.1551 atm, which is a lower limit, and the calculated oxygen concentration (0.2418 kg/m³) is less than the criterion value, which is an upper limit.

Just above that calculation is an estimate of the minimum suit pressure, based on the nitrogen partial pressure of 0.2451 atm, divided by the “no pre-breathe” criterion of factor 1.2. That produces a 0.2043 atm min suit pressure, which meets the “no tissue dry-out” criterion of 3 psia, and also far exceeds the cognition limits. That would be the minimum suit pressure you can use with no pre-breathe interval to blow off nitrogen: you can just don the suit and go right out of the airlock. Any higher suit pressure also qualifies.

Down in the lower right corner of the figure is the habitat leak-down analysis, set by the min partial pressure of oxygen. It says we can leak down 19% in pressure at the same oxygen percentage, and still meet all criteria for safety. Even the fire danger is OK: the oxygen concentration reduces as pressure reduces, depending as it does on density.

Figure 4 below summarizes these results in one place. The “rule of 43” habitat atmosphere allows the use of rather low-pressure space suits without any pre-breathe requirements, and provides plenty of leak-down margin, while at the same time keeping the fire spread danger similar to that in sea level room temperature air. The recommended suit pressure still meets the 3 psia tissue dry-out criterion as leaked-down 10% after a long work shift.

Figure 3 – Oxygenation Issues for Space Habitats

Figure 4 – Results for Combined Habitats and Space Suits

Final Remarks

There are other habitat 2-gas mixtures and pressures that would qualify. Not all of these produce space suit designs with min pressures as low as the one found here.

My selection of the “rule of 43” habitat atmosphere is based on previous work I did trying to meet all these criteria while getting as low a suit pressure as possible. It is also an easy specification to remember. Further, that lowered suit pressure is important for 2 very compelling reasons:

First, a higher suit pressure not only is more difficult to design, it also stiffens like a sports ball at higher pressures, greatly reducing the mobility available to its wearer.

Second, higher suit pressures pretty much rule out suit designs based on mechanical counter-pressure (MCP), since the materials and design practices for MCP are unavailable in any form that might be donned and doffed with reasonable ease at higher pressures.

References:

All these listed references are prior studies posted at http://exrocketman.blogspot.com. For rapid access, there is an archive tool on the left side of that page. All you need is the posting date and the title. Click on the year, then the month, then the title if need be (such as if other articles were posted that same month).

1-2-22 Refining Proposed Suit and Habitat Atmospheres best case and easiest-to-remember cases, plus an independent estimate of the utter min suit pressures feasible

1-1-22 Habitat Atmospheres and Long-Term Health adds a long term hypoxia criterion for the habitat in addition to short term criteria for the min-P suit

3-16-18 Suit and Habitat Atmospheres 2018

11-23-17 A Better Version of the MCP Spacesuit?

2-15-16 Suits and Atmospheres for Space

1-15-16 Astronaut Facing Drowning Points Out Need for Better Space Suit

11-17-14 Space Suit and Habitat Atmospheres

2-11-14 On-Orbit Repair and Assembly Facility

12-13-13 Mars Mission Study 2013

1-21-11 Fundamental Design Criteria for Alternative Space Suit Approaches

Monday, July 28, 2025

Education Department to be Shuttered by Trump?

Saturday, July 26, 2025

Tank Design for Easy Cryogenic Transfers in Weightlessness

Friday, July 18, 2025

Why Trump Did Not Want To Release the Epstein Files

Tuesday, July 8, 2025

Oxygenation Issues for Habitats and Space Suits

An Ex Rocket Man's Take On It

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