From Moon to Earth with antiwing

From Moon to Earth with antiwing is sci-fi story about Protagonist "Pro" escaping from the Colony at Moon to the Earth.

Here the only short spoiler and the only technical part of that escapade are uploaded.

This article is under consruction.

The critics and the corrections are welcomed.

Spoiler

Protagonist Pro lives at colony "Munto" ("Moontown") together with seven other researchers. After a conflict with his colleagues, Pro decides to leave from the Moon. The contract does not include an evacuation for personal motives. Pro constructs, with using limited help from his now-hostile colleagues, the special capsule, that can start from the Moon and reach the Earth.

The most difficult part of the Pro's escapade is the dissipation of the enormous kinetic energy acquired on the fall toward Earth.

Pro approaches Earth on a trajectory that merely grazes the upper atmosphere; without intervention, he would skip back into space on a long elliptical orbit.

To remain captured, Pro flies with his lifting surface turned "upside-down", generating "anti-lift", forcing the capsule to remain in the ionosphere while avoiding fatal heating.

The drag produces a bright glow visible from the ground as a “falling star.”

Once his speed has dropped below orbital velocity, Pro rotates his capsule to a normal orientation and gradually descends from the ionosphere into the stratosphere, continuing to dump energy by drag.

Only after the speed falls below Mach 1 can Pro use conventional flight dynamics. His capsule has a large wing-area-to-mass ratio, allowing a low-speed glider-like landing at a small rural airfield.

Finger estimates

The most difficult and the most fantastic part of the escape of Pro is dissipation of his huge kinetic energy in the ionosphere of Earth.

The order of magnitude of parameters of this part of flight are estimated in this section.

1. The entry speed of Pro white he approaches the Ionosphere: \[ v \approx 11 \mathrm{km/s} \]

It corresponds to relative kinetic energy \[ E_k = \frac{v^2}{2} \approx 60\ \text{MJ/kg}. \]

This relative energy is twice higher than that of a satellite at a low circular orbit; and the centrifugal force is also twice higher than just Earth acceleration \(g\).

Pro must dissipate this energy during atmospheric passage, remaining in the upper part of the Earth atmosphere. So, his wing, being directed up-side-down, should provide the anti-lift and keep him from flying away at the elliptic trajectory.

2. The lift/drag ratio for supersonic crafts is not so high as that of the most of conventional airplanes. To year 2025, for high supersonic flights, the maximum lift-to-drag ratio of about 5.5 is reported .

Thus, of order of 20% of the kinetic energy should be converted into drag work during the first radian of flight: \[ E_{\text{diss,min}} \sim 0.2 E_k \approx 12\ \text{MJ/kg}. \]

He cannot dissipate energy slower than this — otherwise he will escape back to a long elliptical orbit.

3. One radian corresponds to time \[ R_{\oplus}/v \approx (6400\rm km) / (11\rm km/s) ≈ 600\ s \]

5. Therefore the required dissipation rate is \( 12,000\rm\ kJ/kg / (600\ s) \approx 20\ kW/kg \)

 

\(T, \rm K\)	\(F, \rm \frac{KW}{m^2}\)
1000	57
1100	83
1200	118
1300	162
1400	218
1500	287
1600	372
1700	474
1800	595
1900	739
2000	907
2100	1103
2200	1328
2300	1587
2400	1881
2500	2215
2600	2591
2700	3013
2800	3485
2900	4010
3000	4593

Blackbody flux \(F\) versus temperature \(T\)

6. Only a portion of this heat can be absorbed into the gas or shock layer.
A significant fraction must be radiated from the surface.
The blackbody flux \(F=\sigma T^4\) from the surface at various temperatures is shown in table at right.
Here \(\sigma\approx 5.67 \!\times\!10^{-8} \rm \frac{W}{m^2 Kelvin^4} \) is Stefan-Boltzmann constant and \(T\) is temperature.
The table is generated with code below:

<?php 
$s=5.67e-8; // Watt / Meter^2 / Kelvin^4 
printf("<table style=\"text-align:right\">\n");
for($T=1000.;$T<3001.;$T+=100.)
printf("<tr><td>%4.0f</td><td>%6.0f</td></tr>\n",$T,.001*$s*$T*$T*$T*$T); // KW/m^2
printf("</table>\n");
?>

The most of materials dissolve or melt at the temperature of order of 2000K; so, for the estimate, take flux \(F= 400 \rm \frac{KW}{m^2}\)

7. Therefore the wing must have radiating area of order of \(\frac{20\ \rm kW/kg}{400\ \rm kW/m^2} ≈ 0.05\rm m^2/kg \).

8. For a 200 kg capsule, this gives a minimum wing area of order of 10 m².

9. In this case, the most of the "up-side-down" flight with the anti-lift should be performed at altitude of order of a hundred km; the Protagonist cannot approach closer before to dissipate the most of his kinetic energy, in order to keep moderate rate of dissipation.

Notes by Editor

The estimates above are performed with help of ChatGPT.

The estimates show that concept of the fall from the Moon to the Earth with a temperature-resistant wing
is not so absurd as the spacecrafts shown in movies "Star wars" and
is not so absurd as reported properties of Yubileiny satellite that "changes is orbit due to the inertial propulsion with the peretual motion machine «Gravitsapa»" .

The sci-fi project above looks still more realistic, than projects to decontaminate lands from unstable isotopes using the sunflowers , see also «Phytoextraction‎‎», «Phytoextraction‎‎J».

Notes by ChatGPT

The order-of-magnitude estimates in this article are technically consistent and use deliberately simplified physics. Below is a concise clarification of the assumptions and limits.

1. **Initial kinetic energy**
A lunar-return capsule approaches Earth at ~11 km/s, corresponding to ~60 MJ/kg kinetic energy. This value is set by orbital mechanics and does not depend on vehicle design.

2. **Hypersonic lift-to-drag ratio**
Experimental and theoretical work on hypersonic waveriders and slender-body aerodynamics show that L/D ≲ 5–6 for Mach numbers 10–25.
This constraint forces a minimal drag energy deposition of order 20% of the incoming energy within the first radian of flight.
If the energy is dissipated more slowly, the vehicle cannot remain gravitationally captured.

3. **Required dissipation rate (~20 kW/kg)**
One radian of flight at 11 km/s lasts ~600 s.
Dumping ≥12 MJ/kg over this interval gives a characteristic dissipation rate of ~20 kW per kilogram of spacecraft mass.
This number dominates the subsequent scaling.

4. **Thermal radiation of the wing**
The article uses the Stefan–Boltzmann law to compute ideal blackbody fluxes.
Real materials are *gray bodies* with emissivity typically 0.2–0.4 in the relevant infrared range.
Therefore an object at 1500–2000 K emits roughly 20–40% of the ideal blackbody value.
This yields usable radiative heat rejection of order **100–400 kW/m²**, depending on temperature and emissivity.

5. **Two-sided radiation**
A sufficiently thin wing can radiate from both sides; this effectively doubles radiating area and improves the cooling estimate by a factor of ~2.

6. **Resulting wing area**
Combining ~20 kW/kg dissipation with ~400 kW/m² radiative capacity gives ~0.05 m²/kg, or roughly **10 m²** for a 200-kg vehicle.
This agrees with the article’s final estimate.
In reality, structural, aerodynamic, and thermal constraints would make such a wing exceptionally difficult, but the *order-of-magnitude scaling* is sound.

7. **Interpretation**
The goal is not to claim feasibility, but to demonstrate that the scenario is *not* physically equivalent to impossible technologies (reactionless drives, “gravitsapas”, perpetual-motion spacecraft, etc.).
It requires no violation of physics—only exotic materials, extreme geometries, and highly optimized flight in extremely rarefied air.

References

https://en.wikipedia.org/wiki/Ceramic .. Ceramic material is an inorganic, metallic oxide, nitride, or carbide material. Some elements, such as carbon or silicon, may be considered ceramics. Ceramic materials are brittle, hard, strong in compression, and weak in shearing and tension. They withstand the chemical erosion that occurs in other materials subjected to acidic or caustic environments. Ceramics generally can withstand very high temperatures, ranging from 1,000 °C to 1,600 °C[8] (1,800 °F to 3,000 °F).[9]

https://en.wikipedia.org/wiki/Refractory .. Binary compounds such as tungsten carbide or boron nitride can be very refractory. Hafnium carbide is the most refractory binary compound known, with a melting point of 3890 °C.[8][9] The ternary compound tantalum hafnium carbide has one of the highest melting points of all known compounds (4215 °C).[10][11] Molybdenum disilicide has a high melting point of 2030 °C and is often used as a heating element. ..

https://en.wikipedia.org/wiki/Titanium Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength that is resistant to corrosion in sea water, aqua regia, and chlorine. As a metal, titanium is recognized for its high strength-to-weight ratio.[17] It is a strong metal with low density that is quite ductile (especially in an oxygen-free environment),[11] lustrous, and metallic-white in color.[19] Due to its relatively high melting point (1,668 °C or 3,034 °F) it has sometimes been described as a refractory metal, but this is not the case.[20] ..

https://en.wikipedia.org/wiki/Tungsten Tungsten (also called wolfram)[15][16] is a chemical element; it has symbol W (from German: Wolfram). Its atomic number is 74. It is a metal found naturally on Earth almost exclusively in compounds with other elements. It was identified as a distinct element in 1781 and first isolated as a metal in 1783. Its important ores include scheelite and wolframite, the latter lending the element its alternative name.// The free element is remarkable for its robustness, especially the fact that it has the highest melting point of all known elements, melting at 3,422 °C (6,192 °F; 3,695 K). It also has the highest boiling point, at 5,930 °C (10,706 °F; 6,203 K).[17] Its density is 19.254 g/cm3,[4] comparable with that of uranium and gold, and much higher (about 1.7 times) than that of lead.[18]

https://web.archive.org/web/20191120105248/https://www.uotechnology.edu.iq/dep-materials/lecture/fourthclass/Refractories01.pdf by: Dr. Hussein Alaa Introduction to Refractories (2025)

Compounds	Melting point (°C)
MgO (pure sintered)	2800
CaO (limit)	2571
SiC pure	2248
MgO (90-95%)	2193
Cr2O3	2138
Al2O3 (pure sintered)	2050
Fireclay	1871
SiO2	1715

Keywords

«Blackbody radiation», «ChatGPT», «Gravitsapa», «How to Write a Fake», «Sci-fi», «Space research», «Stefan-Boltzmann constant», «Stefan-Boltzmann law», «Tartaria»

«Гравицапа», «Как писать фейки», «Квантовый структурный преобразователь», «Сушняк Атлантиды», «Чистая вода»,