Large thermal protection system panel

• US 20020096601A1
• Filed: 01/24/2001
• Published: 07/25/2002
• Est. Priority Date: 01/24/2001
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Tran, Tu T., Weinberg, David J., Myers, Franklin K.
• Granted Patent: US 6,505,794 B2
• Time in Patent Office: Days
• US Class Current: 244/121
• CPC Class Codes: B64G 1/14 Space shuttles reusable launch rockets B64G1/006
• CPC Class Codes: B64G 1/58 Thermal protection, e.g. heat shields
• CPC Class Codes: B64G 1/62 Systems for re-entry into the earth's atmosphere; Retarding or landing devices

Abstract

A protective panel for a reusable launch vehicle provides enhanced moisture protection, simplified maintenance, and increased temperature resistance. The protective panel includes an outer ceramic matrix composite (CMC) panel, and an insulative bag assembly coupled to the outer CMC panel for isolating the launch vehicle from elevated temperatures and moisture. A standoff attachment system attaches the outer CMC panel and the bag assembly to the primary structure of the launch vehicle. The insulative bag assembly includes a foil bag having a first opening shrink fitted to the outer CMC panel such that the first opening and the outer CMC panel form a water tight seal at temperatures below a desired temperature threshold. Fibrous insulation is contained within the foil bag for protecting the launch vehicle from elevated temperatures. The insulative bag assembly further includes a back panel coupled to a second opening of the foil bag such that the fibrous insulation is encapsulated by the back panel, the foil bag, and the outer CMC panel. The use of a CMC material for the outer panel in conjunction with the insulative bag assembly eliminates the need for waterproofing processes, and ultimately allows for more efficient reentry profiles.

Claims

1. A protective panel for a reusable launch vehicle, the protective panel comprising:

an outer ceramic matrix composite (CMC) panel for isolating the launch vehicle from elevated temperatures;

an insulative bag assembly coupled to the outer CMC panel for isolating the launch vehicle from elevated temperatures and moisture; and

a standoff attachment system for attaching the outer CMC panel and the bag assembly to a tank wall of the launch vehicle.

2. The protective panel of claim 1 wherein the insulative bag assembly includes:

a foil bag having a first opening shrink fitted to the outer CMC panel such that the first opening and the outer CMC panel form a water tight seal at temperatures below a desired temperature threshold;

fibrous insulation contained within the foil bag for further protecting the launch vehicle from elevated temperatures; and

a back panel coupled to a second opening of the foil bag such that the fibrous insulation is encapsulated by the back panel, the foil bag, and the outer CMC panel.

3. The protective panel of claim 2 wherein the desired temperature threshold is approximately 400°

F.

4. The protective panel of claim 2 wherein the back panel is corrugated such that stiffness is increased along a predetermined axis of the back panel.

5. The protective panel of claim 2 wherein the back panel includes titanium.

6. The protective panel of claim 1 wherein the outer CMC panel includes a plurality of stiffening ridges for providing stability to the outer CMC panel, one or more of the stiffening ridges defining an attachment surface for coupling the insulative bag assembly to the outer CMC panel.

7. The protective panel of claim 6 wherein the stiffening ridges include perimeter stiffeners disposed adjacent to a perimeter of the outer CMC panel.

8. The protective panel of claim 7 wherein the perimeter stiffeners are curved to improve coupling between the insulative bag assembly and the outer CMC panel.

9. The protective panel of claim 6 wherein the stiffening ridges include internal stiffeners disposed adjacent to a non-perimeter region of the outer CMC panel.

10. The protective panel of claim 1 wherein the outer CMC panel includes C/SiC.

11. The protective panel of claim 1 wherein the standoff attachment system includes:

a plurality of attachment devices fixed to the tank wall of the launch vehicle at predetermined wall locations;

a plurality of standoffs coupled to the outer CMC panel at predetermined panel locations, each standoff extending between a panel location and a corresponding wall location;

a plurality of attachment fittings fixed to the standoffs for coupling the standoffs to the attachment devices.

12. The protective panel of claim 11 wherein the standoffs are arranged in a predetermined configuration such that thermal expansion stresses in the outer CMC panel are reduced.

14. The bag assembly of claim 13 wherein the desired temperature threshold is approximately 400°

F.

15. The bag assembly of claim 13 wherein the back panel is corrugated such that stiffness is increased along a predetermined axis of the back panel.

16. The bag assembly of claim 13 wherein the back panel has a curved perimeter.

18. The method of claim 17 further including the step of heating the foil bag and the outer CMC panel to approximately 800°

F.

19. The method of claim 17 further including the steps of:

disposing fibrous insulation within the foil bag; and

coupling a back panel to a second opening of the foil bag such that the fibrous insulation is encapsulated by the back panel, the foil bag, and the outer CMC panel.

20. The method of claim 19 further including the step of attaching the outer CMC panel, the foil bag, and the back panel to a tank wall of the reusable launch vehicle with a standoff attachment system.

13. An insulative bag assembly for a reusable launch vehicle protective panel, the bag assembly comprising:

a foil bag having a first opening shrink fitted to an outer panel such that the first opening and the outer panel form a water tight seal at temperatures below a desired temperature threshold;

fibrous insulation contained within the foil bag for protecting the launch vehicle from elevated temperatures; and

a back panel coupled to a second opening of the foil bag such that the fibrous insulation is encapsulated by the back panel, the foil bag, and the outer panel.

17. A method for fabricating a reusable launch vehicle protective panel, the method comprising the steps of:

heating a foil bag and an outer ceramic matrix composite (CMC) panel to a predetermined stretching temperature, the stretching temperature defining a temperature threshold at which the foil bag expands to a circumference that is greater than a circumference of an attachment surface of the outer CMC panel;

positioning a first opening of the foil bag around the attachment surface of the outer CMC panel; and

cooling the foil bag and the outer CMC panel to a predetermined shrinking temperature, the shrinking temperature defining a temperature threshold at which the foil bag attempts to retract to a circumference that is less than the circumference of the attachment surface.