Quick installation-removal thermal insulation blanket for space craft

The invention provides a thermal insulation blanket suitable for removable mounting on a structure such as the exterior of a reusable launch vehicle. In one embodiment, the invention include a batting layer with a rigid screen embedded within it. A cover layer is secured over the batting, and a plurality of fasteners are held by the screen in a position where they extend out from the blanket to be mounted on the exterior of the space craft. The blanket can include two layers of batting with the screen disposed therebetween. The structure would have corresponding mating fasteners on its exterior to which those extending out from the blanket cover would be joined for a secure mount. The blanket can be formed of a first and a second batting layer with the screen positioned therebetween. In a preferred embodiment, a cover would be positioned over the batting layers, and the blanket would be quilted to hold the layers and cover in close proximity. In an embodiment suitable for launch vehicle use, the materials used for the batting, cover and quilting thread would be suitable ceramic fiber materials capable of withstanding reentry heating. The screen can be fabricated of titanium, stainless steel, or other material capable of withstanding reentry temperatures. The fasteners could be any of a variety of commercially available fasteners.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to the field of thermal insulation blankets, and 
more particularly to thermal protection for spacecraft. 
2. Background Information 
Reusable space launch vehicles such as the Space Shuttle need thermal 
insulation to protect the vehicle from heat during reentry. Currently, 
flexible quilted ceramic blankets are used to cover a portion of the 
exterior of such vehicles for heat protection. The flexible blankets 
usually are on the order of a few feet in length. They are constructed of 
a ceramic fiber batting surrounded by a ceramic fabric cover material, 
which is quilted with ceramic thread to form a blanket on the order of an 
inch or two thick. These are typically mounted on the vehicle exterior by 
silicon rubber adhesive. Blankets adhered to a structure by adhesive often 
do not withstand high acoustic loads, on the order of 165 dB, for example. 
Acoustic loads of this magnitude often cause the quilting threads to 
break, and the batting to separate and puff up. This reduces the 
performance of the insulating blanket to unacceptable levels. 
The blankets often must be removed and replaced for inspection and repair. 
The process of installing and removing the blankets is time-consuming and 
expensive. Turn-around time for reusable launch vehicles will be 
increasingly critical to their success, and the time involved in removal 
and replacement of insulation blankets mounted with adhesive will be an 
obstacle to achieving goals for turn around time for future reusable 
launch vehicles. 
What is needed, then, is a means for quick installation and remove of 
flexible blankets, which requires very little skill to ensure complete and 
safe mounting, with minimal room for human error, and in a manner which 
will allow the blanket to withstand the extreme acoustic loads to which it 
will be subjected during launch. 
SUMMARY OF THE INVENTION 
The invention provides a thermal insulation blanket suitable for removable 
mounting on a structure such as the exterior of a reusable launch vehicle. 
In one embodiment, the invention includes a batting layer with a rigid 
screen embedded within it. The embedded screen arrangement can be provided 
by sandwiching the screen between two layers of batting. A cover layer is 
secured over the batting, and a plurality of fasteners are held by the 
screen in a position where they extend out from the blanket to be mounted 
on structure. The structure would have corresponding mating fasteners on 
its exterior to which those extending out from the blanket cover would be 
joined for a secure, removable mount. 
The blanket can be formed of a first and a second batting layer with the 
screen positioned therebetween. In a preferred embodiment, the cover would 
be positioned over the batting layers, and the blanket would be quilted to 
hold the layers and cover in close proximity. 
In an embodiment suitable for launch vehicle use, the materials used for 
the batting, cover and quilting thread would be suitable ceramic fiber 
materials capable of withstanding reentry heating. The screen can be 
fabricated of titanium, stainless steel, or other material capable of 
withstanding reentry temperatures. The fasteners could be any of a variety 
of commercially available fasteners.

DESCRIPTION OF A PREFERRED EMBODIMENT 
For purposes of illustration, a rectangular blanket about two feet by four 
and about an inch thick is shown, although blankets of any size or shape 
can be made in accordance with the invention. The illustrated embodiment 
is particularly suitable for launch vehicle use, although blankets 
constructed according to the invention can be made for any insulating 
application, with appropriate choice of materials. For example, blankets 
according to the present invention could be used in industrial 
applications, such as those involved with furnaces or kilns, or to 
insulate the interior of commercial aircraft. 
Referring to the Figures, an insulating blanket 10 according to a preferred 
embodiment of the invention is suitable for use as advanced flexible 
reusable surface insulation (AFRSI) on a reusable launch vehicle. For 
launch vehicle use, the materials used are chosen for high heat resistance 
and low weight. The blanket 10 preferably is made of a low density ceramic 
batting 12 of a material such as silica or alumina. Such a batting is 
available commercially, for example the batting sold under the trade name 
SAFFIL by ICI. A cover 14 made of a ceramic woven material such as that 
sold by 3M Corporation under the trade name NEXTEL 312 or NEXTEL 440 is 
disposed around the batting 12. The blanket 10 is quilted or stitched 
together with ceramic thread 16 such as NEXTEL 440 sewing thread (also 
available from 3M Corporation). In the illustrated embodiment, a square 
quilting pattern is used. 
In the preferred embodiment, a substantially rigid screen 18 is embedded 
within the batting 12. This can be accomplished by placing the screen 18 
between a first and second batting layer 20, 22 respectively. Preferably, 
the layer 20 on top of the screen 18 is thicker than the layer 22 below 
(on the side which will be in proximity to the structure to which the 
blanket will be mounted in use). The bottom batting layer 22 prevents 
abrasive contact between the screen 18 and cover 14, and prevents 
undesirable heating effects and abrasion which would be present if the 
screen were in contact with the structure or separated therefrom only by 
the cover 14. For other applications, it may be acceptable for the screen 
18 to lie on the surface of the batting, rather than being embedded or 
layered within it. For launch vehicle use, the screen material should be 
one which can perform in the temperature environment of spacecraft 
reentry, while being light weight. Titanium and stainless steel are two 
examples of acceptable materials. In a preferred embodiment, a coarse mesh 
screen of about 0.25 inch openings is acceptable. 
The screen 18 is of a size and overall dimension so as to be substantially 
co-extensive with the blanket 10. Blankets of irregular perimeter shape 
can be fashioned using the present invention. 
The screen 18 supports fasteners 24 which are held in a position where they 
extend out from the bottom of the blanket 10. Preferably, the external end 
of the fastener 24 is substantially flush with the blanket's surface. 
Preferably, the fasteners will be arranged in a rectangular array (see 
FIG. 4), at a spacing which is adequate for secure affixation to the 
structure on which the blanket is installed. The fasteners can be any of a 
wide variety of commercially available fasteners, although a fastener sold 
under the trade name RIVNUT by Rivnut Engineering Products has been found 
to be advantageous because it can be easily installed in the screen 18 
after the cover 14 has been placed on the blanket 10, since it can be 
inserted through the cover fabric. Corresponding mating fasteners 28 (see 
FIG. 5) on the structure 30 to which the blanket will be mounted, such as 
the exterior surface 30 of a reusable launch vehicle, are arranged to 
receive the fasteners 24 extending from the blanket 10. 
A blanket and structure with the mounting system of the preferred 
embodiment allows for quick installation and removal of the blanket, 
requiring little or no specialized skill. 
Although the invention has been described above with respect to certain 
specific embodiments, the scope of the invention is not limited to the 
specific embodiments disclosed. Other designs within the spirit and scope 
of the invention will be apparent to those skilled in the field after 
receiving the above teachings. The scope of the invention, therefore, is 
defined by reference to the following claims.