JP2696648B2 - Ablator structure for spacecraft - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The disclosed technology is a self-sustained return capsule or a shell of a planetary exploration capsule that is launched into a predetermined space orbit, performs various experiments, and then reenters the atmosphere and is recovered. Belongs to the technical field of thermal protection material structure.

[0002]

2. Description of the Related Art As is well known, modern civilization greatly depends on the phenomenal development of science and technology. However, in recent years, when the working resources are considered to be finite, the rise of various industries on a global scale has recently occurred. With the accompanying pollution and environmental issues being highlighted, various industries are no longer ignoring pollution prevention and environmental harmonization issues, and the effective use of momentum resources and the development of science and technology have shifted from micro to macro. The science and technology that supports it has expanded widely from the micro to the macro fields in both theory and experiments, and has been expanding to the cosmic scale of resource exploration and macro science. There is a growing need for demonstrations.

Therefore, exploration of earth resources and environment from outer space, various gravityless experiments outside the atmosphere, various demonstrations in outer space including planetary exploration, and data analysis will be considered. Therefore, the development of spacecraft such as so-called capsules related to the launching of a rocket into the outer space, the recovery of the airframe including experimental data, the space flight, etc. has been spurred.

[0004] Various experimental data and observation data in outer space can be used by information exchange through radio communication between the spacecraft and the earth base, but are preferably obtained. The technology of collecting the collected data on the ground together with the spacecraft is extremely important together with the data collection in the outer space.

By the way, a capsule as a spacecraft such as a rocket flying from the ground to the outside of the atmosphere rises relatively slowly. However, as a spacecraft which has been observed and tested in a predetermined orbit in outer space. Capsules take the process of re-entering the atmosphere to be recovered on the ground,
In the process, in the atmosphere at altitudes of 80 km to 120 km or less, so-called aerodynamic heating for several minutes is inevitably caused by friction with air, and basically there is a risk of burning out of the capsule, so that heat protection for the outer skin is performed. Means are required.

When a planetary exploration capsule such as Venus or Jupiter enters the atmosphere of the star, it receives a high heating rate and a large dynamic pressure more than the reentry of the Earth's atmosphere. It is necessary to provide a heat-resistant protective means against the outer skin that is better than the entry into the hull.

[0007] Observational data, experimental data, and
So-called ablators are used as thermal protection materials for the outer skin in capsules for reentry into the atmosphere, etc., in which capsules containing various equipment and devices for collecting the data are self-sustained return type, and from the classic heat-resistant type structure Recently, an excellent ablator structure such as a sublimation type, a fusion type, and a carbonization type ablator 1 shown in FIG. 3 has been developed, and is being used for spacecraft such as an Apollo spacecraft and a Galileo probe (Jupiter exploration capsule). .

[0008] The matrix of the prepreg used in such an ablator is silicon-based, epoxy-based,
Phenol-based ones have been developed, but various experiments and practical data from spacecraft have shown that the temperature inside the fuselage increases due to the large heat absorption accompanying the generation of pyrolysis gas by aerodynamic heating when entering the atmosphere. From the various merits such as prevention of heat input and prevention of heat input by covering the outer surface of the ablator with a pyrolysis gas, research into promoting the practical use of the carbonized ablator 1 shown in FIG. 3 using a phenolic resin will be conducted. It is becoming.

Such an ablator is also disclosed, for example, in US Pat. No. 4,077,921.

[0010]

Thus, for example, the Apollo spacecraft has a relatively low density (about 0.5 g / c).
While using epoxy ablator of m ^3), because by the data used in low dynamic pressure conditions, large when the amount of loss used in conditions of high heating rate, Kodo圧the equivalent It is expected that the thickness of the ablator must be increased, resulting in a drastic increase in weight.

In Galileo (Jupiter exploration capsule),
Although an ablator with sufficient wear resistance under high heating rate and high dynamic pressure conditions is used, it has the drawback of high density (about 1.5 g / cm ³ ), There was a demerit that became a bottleneck in reducing the weight of the capsule as a spacecraft whose weight reduction was the highest order, including when the rocket went up.

[0012] Therefore, there is a disadvantage that various materials and equipment to be mounted are restricted, and as a result, there is a problem that it may hinder valuable data collection.

[0013]

SUMMARY OF THE INVENTION The object of the invention of this application is to provide a high-density and high-heat-inhibiting effect based on the above-mentioned prior art, and to have a great effect of suppressing the temperature rise in the machine. The technical problem to be solved is that the contradictory functions of the weight reduction effect, the heat protection function, and the surface wear and abrasion resistance function can be mutually exchanged. The ablator structure for spacecraft is not provided, which has a protective function, can reduce the weight of the spacecraft, and has flexibility in the mounting capacity of various equipment. It is assumed that.

[0014]

Means for Solving the Problems According to the above objects, the constitution of the invention of the present application, which is summarized in the above-mentioned claims, is to solve the above-mentioned problems by using a self-sustained return type capsule, a planetary exploration capsule, etc. In order to form an ablator for the outer skin of a spacecraft, a prepreg in which silica short fibers are dispersed and mixed in a predetermined manner in a phenol resin is used to form a two-layer ablator. In the process of integrally forming the ablator of the eye, phenol microballoons in the form of microspheres are mixed into the ablator of the second layer in a dispersed state with respect to the ablator of the second layer. The phenol microballoons are dispersed in an inclined form or stepwise from the dense to the sparse state from the latter to the former. The high-density ablator has a large conductivity but a small amount of surface wear. The second layer ablator has a large amount of surface wear, but has a small weight and thermal conductivity. However, due to aerodynamic heating when the spacecraft reenters the atmosphere, the amount of surface wear is sufficiently small, and due to the carbonized type, the first and second layers absorb a large amount of heat due to the thermal decomposition of the ablator, which is generated by the thermal decomposition When the gas passes through the carbonized layer, it further deprives the heat, and the second layer prevents the temperature rise inside the machine and the machine due to its excellent heat insulating effect. Heat from the outside can be prevented, the aircraft itself,
And the equipment to be mounted, and the collected data etc. can reach the ground or be collected without any trouble,
Technical measures are taken to reduce the weight of the body, to increase the degree of freedom in selecting the type and weight of materials to be mounted, to facilitate control, and to suppress cost increase.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; FIG.

The same parts as those in FIG. 3 are described using the same reference numerals.

In the illustrated embodiment, reference numeral 6 denotes an ablator which forms the center of the gist of the invention of this application. This embodiment is an embodiment used for the outer shell (mission system or the like) of a self-sustained return type capsule as a spacecraft. The thickness is, for example, 50 mm by design, and the outer first layer of the ablator 1
Is designed to be, for example, about 10 mm, the second-layer ablator 2 integrated with the first-layer ablator 1 is set to about 40 mm, and both ablators 1, 2 are made of phenol resin 5. The prepreg of the ablator 1 is integrally molded with a prepreg, and the prepreg of the ablator 1 contains a predetermined amount of the silica short fibers 4 in a uniformly dispersed state. Using the prepreg mixed in the quantitatively dispersed state, the boundary portion (there is no physical or mechanical boundary) from the second layer ablator 2 to the first layer ablator 1 is steplessly inclined or stepped. The former is dispersed from a dense state to a sparse state.

Therefore, structurally the outermost ablator 1 is a single layer ablator 1 of the conventional mode shown in FIG.
Similarly, the surface wear amount is small, the weight and the thermal conductivity are large, and the surface wear amount due to aerodynamic heating upon re-entry into the atmosphere is small.

The inner second layer of the ablator 2 is lightened by the scattered phenol microballoons 4 and, when directly heated by friction with the atmosphere, is covered with the first layer, although the surface wear is large. The risk of direct heating is low, the thermal conductivity is also reduced,
The thermal influence on the airframe and the equipment mounted in the airplane is small.

In addition, since the microballoons of the second layer are densely and sparsely dispersed from the second layer to the first layer, rapid weight reduction is not achieved from the first layer to the second layer. , The above functions are implemented slowly.

The pyrolysis by aerodynamic heating and the generation of pyrolysis gas are performed as designed, as in the conventional carbonized ablator, and the short silica fibers 4 prevent cracking and peeling, and the carbonized layer is also formed. By strengthening, the amount of surface wear can be reduced, and the function as an ablator can be sufficiently maintained.

It should be noted that the embodiment of the invention of this application is not limited to the above-mentioned embodiment, and the object of application is not limited to the self-sustained return type capsule, but also to planetary exploration capsules, other spacecrafts and rockets, etc. Applied to spacecraft,
The exact thickness dimensions of the outer first layer ablator 1 and the inner second layer ablator 2 are within the scope of design changes as appropriate.

[0023]

As described above, according to the invention of this application, after basically flying in a predetermined orbit in outer space, collecting observation data and experimental data as designed, and then re-entering the earth's atmosphere. An ablator mounted on the outer skin of a spacecraft such as a self-sustained return-type capsule that returns to the ground, or a planetary explorer that enters the atmosphere of Venus or Jupiter, etc., exposed to higher heating rates and higher dynamic pressure conditions In the ablator provided on the outer skin, the structure is a carbonized ablator of a two-layer structure, the outer first ablator is a high-density ablator with small surface wear, weight and thermal conductivity, and The second layer ablator is a low-density ablator with large surface wear but low weight and thermal conductivity.The second layer ablator is thicker than the first layer ablator to reduce the overall weight of the ablator. In addition, the outer layer ablator reduces the amount of surface wear through aerodynamic heating at the time of entry into the atmosphere, and the outer layer, and the inner layer ablator absorbs a large amount of heat due to thermal decomposition, When the gas generated by thermal decomposition passes through the carbonized layer, it further deprives the heat, the heat insulation effect of the second layer is also suppressed, and the temperature rise inside the machine is suppressed. The ablator, which prevents heat input to the fuselage, allows the spacecraft to withstand aerodynamic heating sufficiently, and reduces the weight by interposing the second layer of microballoons in a dispersed state, which is inherently contradictory Function to make use of each other's strengths, complement each other's weaknesses, collect valuable observational data and experimental data on the earth without any trouble, or safely send the planetary explorer to the planet's atmosphere. Excellent effect that is achieved.

In addition to the reduction in weight, there is also an effect that the degree of freedom in selecting the type and weight of observation and experimental equipment to be mounted is increased.

Further, since the dispersion state of the second layer of microballoons from the first layer to the first layer is reduced from honey, an excellent effect that each of the above functions is moderately achieved is exhibited.

Since the silica short fibers are dispersed in the ablator, cracks and peeling due to aerodynamic heating can be prevented, the carbonized layer can be strengthened, the amount of surface wear can be reduced, and the function of the ablator can be reduced. An excellent effect that it can be sufficiently held is exhibited.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of the invention of this application.

FIG. 2 is an enlarged sectional view of a main part of FIG.

FIG. 3 is a sectional view of a carbonized ablator according to the prior art.

[Explanation of symbols]

 6 Ablator (whole) 1st layer ablator 2 2nd layer ablator 3 Phenol micro balloon 4 Silica short fiber 5 Phenol resin

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshifumi Inatani 1748-15 Hanbara, Aiko-cho, Aiko-gun, Kanagawa Prefecture (56) References JP-A-5-286069 (JP, A)

Claims (3)

(57) [Claims] In a two-layer carbonized ablator structure in which phenol microballoons are scattered on a phenol resin and attached to the outer surface of a spacecraft, an outer first ablator and an inner second ablator are provided. the phenolic resin is integrally molded, silica fibers to both of the phenolic resin is a mixed dispersed state, is the first layer of the ablator has a high density surface wear amount is small weight and thermal conductivity of the large ablator, a second layer of the ablator weight surface wear amount large, the thermal conductivity is in a small low-density ablator, the second layer of the ablator is dispersed and mixed phenol microballoons in a predetermined, upper Symbol phenol micro balloon Thus the second layer
From the ablator to the first ablator
An ablator structure for a spacecraft characterized by being dispersed in a spacecraft. 2. The ablator structure for a spacecraft according to claim 1, wherein said dispersion is stepless. 3. The ablator structure for a spacecraft according to claim 1, wherein said dispersion is stepped.