Communications: radio wave antennas – Antennas – Mesh – woven – braided or multiple strip
Reexamination Certificate
2002-07-08
2004-09-14
Nguyen, Hoang V. (Department: 2821)
Communications: radio wave antennas
Antennas
Mesh, woven, braided or multiple strip
C343S912000, C343S915000
Reexamination Certificate
active
06791510
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an inflatable structure for supporting and reinforcing an object arranged in outer space, an array antenna with the inflatable structure, and a method of deploying the inflatable structure.
BACKGROUND ART
An object of an inflatable structure is to support and reinforce an object (for example, an antenna or the like) arranged in outer space. Such an inflatable structure has been researched and developed in recent years, and has been put to practical use.
An inflatable structure is formed by a sealed, bag-shape member. When the bag-shape member is folded up, a gas or the like is filled into an internal portion thereof, whereby internal pressure thus generated causes the member to reassume a tube shape, a balloon shape or other such desired shape.
In a case where the inflatable structure is of the tube shape, there are instances where the structure itself may serve as a prop or as a truss structure or other such unit member. Further, the inflatable structure can also be constructed as a square ring or as an annular ring tube, which extends in tension a membrane surface having an antenna element mounted on its inner side, to thereby support the antenna.
On the other hand, in a case where the inflatable structure is a balloon shape, the structure can also function as a part of a reflective mirror antenna, where the structure itself serves as a reflective surface.
A specific example of this type of inflatable structure will now be explained with reference to FIG.
17
.
FIG. 17
is a perspective view showing an antenna arranged in outer space, in a state supported by the inflatable structure.
As shown in
FIG. 17
, an antenna
100
is basically composed of an inflatable structure
101
, a plane antenna
102
supported by the inflatable structure
101
, and a plurality of tensioning cables
103
for supporting the plane antenna
102
with the inflatable structure
101
.
The plane antenna
102
is composed of a disc-shape membrane surface with an antenna element mounted onto it. The inflatable structure
101
is a ring tube shape and is arranged surrounding the plane antenna
102
.
Further, when the inflatable structure
101
is extended in tension, the plane antenna
102
is tensioned and extended by means of the tensioning cables
103
. Accordingly, by being pulled in each different direction along the plane surface, the plane antenna
102
is supported by the inflatable structure
101
such that it maintains its surface geometry.
In a case where a reflective mirror is to be reproduced instead of the above-mentioned flat surface structure, a lens-type reflective mirror that is extended in tension in the interior space is also constructed using the inflatable structure.
A procedure for arranging the above-mentioned antenna
100
in outer space, such as in a satellite orbit, will now be explained.
First, the plane antenna
102
and the inflatable structure
101
are both stored inside a rocket fairing in their rolled or folded states.
Then the rocket is launched, and the antenna
100
is set on its satellite orbit. In this state, a gas or a urethane foam is filled into the inflatable structure
101
to deploy (restore) the inflatable structure
101
to its ring tube shape.
In this way, the plane antenna
102
which is in the rolled or folded state is extended, and the tensioning cables
103
pull uniformly on the membrane surface periphery of the plane antenna
102
, to extend it into a flat plane without distortions.
Even when the inflatable structure described above is used with a large-scale structure to be arranged in out space, such as the antenna, the structure can be folded for example, so that the volume thereof can be reduced when it is launched using the rocket.
The above-mentioned structural characteristics are effective for putting equipment into satellite orbits when the mass (payload) that can be launched and the storage capacity of the fairing of the rocket are limited. Further, the characteristics are also effective for reducing the mass of each structure constituting an artificial satellite that will be put into satellite orbit and for reducing the cost of launching. Therefore, use of inflatable structures is being studied for a wide range of applications as a suitable structure for an antenna mounted on a satellite.
Demand to increase the size of structures arranged in outer space such as in satellite orbit has risen in recent years as space development has progressed.
For example, although the above-mentioned antenna has typically been a relatively small-scale antenna directly fixed and mounted on a low-orbit satellite, there is a demand to expand the diameter across its opening in order to increase its area gain so that it can be used as an antenna that is mounted onto a satellite that is in a stationary satellite orbit.
Further, its used is being studied for many applications, such as for high-speed data communications, radio wave observation satellites, synthetic aperture radar for remote sensing, and solar array mounting.
In order to make these applications practical, it is necessary to increase the size of the structures, including the antenna, the reflective mirror and the like. Further, regarding the antenna, there is a need to improve its area gain, side lobe level, directivity and other such electrical performance as well. Thus, a further increase in the precision level is necessary.
In order to satisfy these needs, examples of plane antennae and the like, which employ the inflatable structure, include one which is currently being developed in which the size of one side thereof exceeds 10 m. Moreover, an antenna in which the size of one side reaches several tens of meters is also being planned.
As described above, while there is a demand to increase the size of structures arranged in outer space, there is a need to reduce the mass and improve storability (compactness during storing) in light of restrictions on the payload of the launching rocket and the volume of the fairing where the structure is to be stored.
Therefore, there is a need to fulfill contradictory objects of increasing the size of the structure to be arranged in outer space and of reducing the mass of the structure and making it more compact when it is stored. Satisfying all these demands simultaneously entails technical difficulty.
In order to satisfy the demand for the reduced mass, it is necessary to employ a construction using a very strong and very elastic material, to increase the specific strength and the specific modulus of the inflatable structure.
On the other hand, when the size of the structure is increased, the overall flexibility of the structure increases, which means that even the slightest differences in the structure or in the manufacturing process result in distortions and deformations in the structure.
Further, the above-mentioned spaceborne structure must be very reliable regarding its structure and also with respect to environment. In a case where the bag-shape membrane that constitutes the inflatable structure of a tube shape is formed solely of a film, it has an advantage that it can be made lightmass and have a simple construction. However, in order to maintain the precision level of the structure, the gas pressure inside the inflatable structure must be controlled constantly.
Further, there is a danger that space debris and the like, which is also called space garbage, will cause damage to the membrane structure to cause loss of gas pressure, so that the structure cannot be maintained.
To prevent this, a curing-type resin is layered on these films, and sometimes reinforcing fibers are further layered on top of this, in order to enhance the hardness of the membrane structure. However, since these reinforcing measures increase the mass, there is a need for a structure which is both lightmass and highly reliable.
Thus, the following have been proposed as examples of structures which satisfy these various demands.
One is to increase its strength by using, as the rigidizing layer, aramid fibers or other such woven structur
Senbokuya Yumi
Tsunoda Hiroaki
Watanabe Akihito
Morrison & Foerster / LLP
Nguyen Hoang V.
Sakase Adtech Co., Ltd.
LandOfFree
Inflatable structure, array antenna with inflatable... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Inflatable structure, array antenna with inflatable..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Inflatable structure, array antenna with inflatable... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3233531