4.1 Lessons learned after the Space Shuttle Columbia disaster

During the reentry phase, shock waves produced by hypersonic velocities and the frictional effect of the atmosphere began to heat Columbia's surface. The temperature varied depending on location: the orbiter's nose and leading edges of the wing experiencing temperatures greater than 1538°C [25].

The breach created during launch in the ablative protection of the left wing allowed for hot gases to penetrate the wing and to advance in the same direction inside the wing and to the fuselage (see Figure 18). This phase became known as "phase I" from "Initialization."

During the "Initialization" phase, the wing lost its aerodynamic characteristics, and the destruction process was extremely short, lasting from 13:59:37.5 GMT to 13:59:39.7 GMT (2.2 s) (see Figure 19) [25].

The "Acceleration" phase quickly followed the "phase I" which lasted for 0.07 s. The destruction continued with total dispersal of the space vehicle and burning in the atmosphere (see Figure 20). This phase can be called "phase D" from "Dispersal" and lasted for 55 s (Figure 21).

### 4.2 Space equipment for rapid disintegration during atmosphere reentry

As presented in Chapter 1, ESA's "Design for Demise" concept must be implemented in every space equipment. Following those guidelines, the present paper presents a new vision of that concept.

It is known that satellite equipment is covered by a protection box which shields

them against environmental factors such as cosmic radiation, solar wind, light (ultraviolet, visible, infrared), cosmic dust, and rarefied atmosphere. Usually, this box is a prism which has a pretty low dynamic drag, and, as a result, reaching high temperatures on the surface of the satellite is delayed; therefore the satellite disintegration is delayed during reentry. The situation is even more critical in the

Technologies for Deviation of Asteroids and Cleaning of Earth Orbit by Space Debris

DOI: http://dx.doi.org/10.5772/intechopen.86565

Figure 19.

Figure 20.

27

Initiation phase of the destruction process (phase I) [25].

Acceleration phase of the destruction process (phase A) [25].

Technologies for Deviation of Asteroids and Cleaning of Earth Orbit by Space Debris DOI: http://dx.doi.org/10.5772/intechopen.86565

Figure 19. Initiation phase of the destruction process (phase I) [25].

Figure 20. Acceleration phase of the destruction process (phase A) [25].

It is known that satellite equipment is covered by a protection box which shields them against environmental factors such as cosmic radiation, solar wind, light (ultraviolet, visible, infrared), cosmic dust, and rarefied atmosphere. Usually, this box is a prism which has a pretty low dynamic drag, and, as a result, reaching high temperatures on the surface of the satellite is delayed; therefore the satellite disintegration is delayed during reentry. The situation is even more critical in the

the wing creating an irregular hole. Air entered the left wing with high speed, quickly became very hot when stagnating, and destroyed the internal structure of

During the reentry phase, shock waves produced by hypersonic velocities and

The breach created during launch in the ablative protection of the left wing allowed for hot gases to penetrate the wing and to advance in the same direction inside the wing and to the fuselage (see Figure 18). This phase became known as

During the "Initialization" phase, the wing lost its aerodynamic characteristics, and the destruction process was extremely short, lasting from 13:59:37.5 GMT to

The "Acceleration" phase quickly followed the "phase I" which lasted for 0.07 s.

The destruction continued with total dispersal of the space vehicle and burning in the atmosphere (see Figure 20). This phase can be called "phase D" from

4.2 Space equipment for rapid disintegration during atmosphere reentry

As presented in Chapter 1, ESA's "Design for Demise" concept must be implemented in every space equipment. Following those guidelines, the present

Velocity distribution on Columbia's left wing at the beginning of the disaster (phase I) [25].

the frictional effect of the atmosphere began to heat Columbia's surface. The temperature varied depending on location: the orbiter's nose and leading edges of

4.1 Lessons learned after the Space Shuttle Columbia disaster

the wing experiencing temperatures greater than 1538°C [25].

the wing.

Figure 18.

26

"phase I" from "Initialization."

Planetology - Future Explorations

13:59:39.7 GMT (2.2 s) (see Figure 19) [25].

"Dispersal" and lasted for 55 s (Figure 21).

paper presents a new vision of that concept.

Figure 21. Total dispersal phase (phase D) [25].

case of the last stages of launching rockets which have a good aerodynamic shape in order to have a low aerodynamic drag during the ascending phase of the launch.

Figure 22.

Figure 23.

Figure 24.

29

Stagnation temperature inside the satellite box.

Articulated door design.

Example of satellite box with doors.

DOI: http://dx.doi.org/10.5772/intechopen.86565

Technologies for Deviation of Asteroids and Cleaning of Earth Orbit by Space Debris

According to the space equipment design presented in this paper, special doors must be incorporated in the external fairing of the space equipment. The holes in the fairing can have any shape (rectangular, triangular, hexagonal, circular, etc.) depending on the position of the fairing. Doors fitted on every hole must be articulated by a cylindrical articulation (i.e., to permit a rotation of the door around an axis); this allows the door to open to the interior of the box when external pressure increases and to close when the pressure inside the fairing is higher than the external pressure. The door is fixed to the fairing through brazing with low fusible metals or strong resins (Loctite, Araldite) which decompose at low temperatures (150–200 to 700°C in special cases). Both the resin and metallic alloys must be extremely resistant at low temperatures but must lose their strength when temperature reaches several hundreds of degree Celsius. In in the early stages of the reentry, the epoxy resins decompose at temperatures between 150 and 200°C, and the braze alloys are melting when the local temperature reaches 200–700°C. As a result, the doors (covers) are pushed inside the fairing, and the external air enters inside where stagnates reach extremely high temperatures. The new external geometry of the space equipment leads to an increase of aerodynamic drag and converts kinetic energy into heat, which enhances the burning process.

By placing more doors on the fairing, no matter how the space equipment rotates during reentry, at least one door is opened by the dynamic pressure, and the rest of them are closed by the same dynamic pressure. Heating inside the fairing is maximum due to air stagnation, which leads to a rapid disintegration of the space equipment.

If the covers (doors) are not articulated, they are pushed inside the equipment by the ambient pressure acting on the surface of the fairing. Being pushed inside, the doors allow the air to flow inside the fairing around the equipment, but does not stagnate; thus heating does not occur, and the aerodynamic drag is low. For this reason the heating hate will be lower than when articulated covers are used.

For an even faster disintegration of the space equipment, the satellite components are wrapped in 0.05-mm thick aluminium or magnesium foil. These lightweight foils will burn first followed shortly by the equipment. This new technology can be seen in Figures 22–27.

Applying this design will determine the space debris to be disintegrated according to Space Shuttle Columbia's tragic disintegration phases I, A, and D. Technologies for Deviation of Asteroids and Cleaning of Earth Orbit by Space Debris DOI: http://dx.doi.org/10.5772/intechopen.86565

Figure 22. Example of satellite box with doors.

case of the last stages of launching rockets which have a good aerodynamic shape in order to have a low aerodynamic drag during the ascending phase of the launch. According to the space equipment design presented in this paper, special doors must be incorporated in the external fairing of the space equipment. The holes in the fairing can have any shape (rectangular, triangular, hexagonal, circular, etc.) depending on the position of the fairing. Doors fitted on every hole must be articulated by a cylindrical articulation (i.e., to permit a rotation of the door around an axis); this allows the door to open to the interior of the box when external pressure increases and to close when the pressure inside the fairing is higher than the external pressure. The door is fixed to the fairing through brazing with low fusible metals or strong resins (Loctite, Araldite) which decompose at low temperatures (150–200 to 700°C in special cases). Both the resin and metallic alloys must be extremely resistant at low temperatures but must lose their strength when temperature reaches several hundreds of degree Celsius. In in the early stages of the reentry, the epoxy resins decompose at temperatures between 150 and 200°C, and the braze alloys are melting when the local temperature reaches 200–700°C. As a result, the doors (covers) are pushed inside the fairing, and the external air enters inside where stagnates reach extremely high temperatures. The new external geometry of the space equipment leads to an increase of aerodynamic drag and

converts kinetic energy into heat, which enhances the burning process.

equipment.

28

Figure 21.

Total dispersal phase (phase D) [25].

Planetology - Future Explorations

can be seen in Figures 22–27.

By placing more doors on the fairing, no matter how the space equipment rotates during reentry, at least one door is opened by the dynamic pressure, and the rest of them are closed by the same dynamic pressure. Heating inside the fairing is maximum due to air stagnation, which leads to a rapid disintegration of the space

If the covers (doors) are not articulated, they are pushed inside the equipment by the ambient pressure acting on the surface of the fairing. Being pushed inside, the doors allow the air to flow inside the fairing around the equipment, but does not stagnate; thus heating does not occur, and the aerodynamic drag is low. For this reason the heating hate will be lower than when articulated covers are used.

For an even faster disintegration of the space equipment, the satellite components are wrapped in 0.05-mm thick aluminium or magnesium foil. These lightweight foils will burn first followed shortly by the equipment. This new technology

Applying this design will determine the space debris to be disintegrated according to Space Shuttle Columbia's tragic disintegration phases I, A, and D.

Figure 23. Articulated door design.

Figure 24. Stagnation temperature inside the satellite box.

Figure 25. Example of fuel tank with articulated circular doors.

Figure 26. Example of last-stage rocket with articulated rectangular doors.

Author details

Constantin Sandu<sup>1</sup>

Bucharest, Romania

31

\*, Cristian-Teodor Olariu<sup>1</sup> and Radu-Constantin Sandu<sup>2</sup>

1 Romanian Research and Development Institute for Gas Turbines-COMOTI,

Technologies for Deviation of Asteroids and Cleaning of Earth Orbit by Space Debris

DOI: http://dx.doi.org/10.5772/intechopen.86565

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

2 S.C. Structural Management Solutions S.R.L., Bucharest, Romania

\*Address all correspondence to: constantin.sandu@comoti.ro

provided the original work is properly cited.

Figure 27. Example of satellite equipment wrapped in aluminium or magnesium foil.

Technologies for Deviation of Asteroids and Cleaning of Earth Orbit by Space Debris DOI: http://dx.doi.org/10.5772/intechopen.86565
