EP-4735330-A1 - AEROSTAT AND METHOD OF ITS MANUFACTURE

Abstract

An aerostat having an elongate hollow body having a length defining a local axis of the body, the hollow body being suitable for receiving sufficient lighter-than-air gas, such that the aerostat can become buoyant in air, the aerostat body comprising a sequence of a plurality of joined body portions, each body portion comprising an outer skin and a hollow internal space, wherein the joins are substantially perpendicular to the local axis of the body, the joined body portions comprising two end body portions, and a plurality of internal body portions, so that the joined body portions together form the elongate hollow body; and a method of manufacturing an aerostat according to any one of the preceding claims, comprising the steps of supporting a first body portion to form a first mounted hollow body portion, supporting a second body portion to form a second mounted hollow body portion, bringing the first and second mounted body portions to come into contact such that the outer skins of the first and second body portions come into alignment, followed by joining together the outer skins of the first and second body portions, followed by repeating the process with further body portions, thereby to produce the aerostat having an elongate hollow body.

Inventors

• DAVIDSON, PETER
• HUXLEY, STEWART

Assignees

• Tethercells Limited

Dates

Publication Date

20260506

Application Date

20240627

Claims (20)

1. 1. An aerostat having an elongate hollow body having a length defining a local axis of the body, the hollow body being suitable for receiving sufficient lighter-than-air gas, such that the aerostat can become buoyant in air, the aerostat body comprising a sequence of a plurality of joined body portions, each body portion comprising an outer skin and a hollow internal space, wherein the joins are substantially perpendicular to the local axis of the body, the joined body portions comprising two end body portions, and a plurality of internal body portions, so that the joined body portions together form the elongate hollow body.
2. 2. An aerostat according to claim 1, wherein the length extends between an upper end and a lower end in use, the two end body portions providing both the upper end and lower end of the body.
3. 3. An aerostat according to claim 1 or claim 2, wherein the outer skin comprises a layer of metal foil, sandwiched with a first layer of unidirectional fibres embedded in a cured resin matrix and a second layer of unidirectional fibres embedded in a cured resin matrix, wherein the second layer of unidirectional fibres are oriented at an angle to the first layer of unidirectional fibres.
4. 4. An aerostat according to claim 3, wherein the metal foil is an outermost layer of the outer skin.
5. 5. An aerostat according to claim 3, wherein the skin comprises an outermost layer of metal foil and an innermost layer of metal foil, the metal foils sandwiching between them the cured resin and fibre layers.
6. 6. An aerostat according to any one of the preceding claims, wherein at least one pair of adjacent joined body portions butt together to form a contiguous region of skin with a joining line therebetween, wherein at least one further skin panel is placed to cover the innermost and/or the outermost facing of the joining line, the position of the at least one further skin panel providing a joining region.
7. 7. An aerostat according to claim 6, wherein the adjacent joined body portions have some or all of the layer of metal foil removed within the joining region.
8. 8. An aerostat according to claim 6 or claim 7, wherein the at least one further skin panels do not have an innermost layer of metal foil.
9. 9. An aerostat according to any one of claims 6 to 8, wherein each joining region extends for a length from the joining line that is from 5 to 150, preferably 5 to 50 times the thickness of the outer skin outside the joining line.
10. 10. An aerostat according to any one of the preceding claims, wherein at least one pair of adjacent joined body portions overlap each other to form a contiguous region of outer skin with an overlap region, wherein at least one further skin panel is placed to cover the overlap region.
11. 11. An aerostat according to claim 10, wherein one or both of the adjacent body portions has some metal foil removed in the overlap region.
12. 12. An aerostat according to claim 10 or claim 11, wherein the at least one further skin panels does not have an innermost layer of metal foil.
13. 13. An aerostat according to any one of the preceding claims, wherein each joined body panel has an outer skin thickness of from 0.1 to 5mm, preferably from 0.1 to 3 mm, more preferably 0.2mm to 2mm.
14. 14. An aerostat according to any one of the preceding claims, wherein a plurality of the internal body portions to be essentially identical.
15. 15. An aerostat according to any one of the preceding claims, wherein at least 70% of the surface area of the body portions have a minimal principal curvature of zero, and the maximum principal curvature is non-zero.
16. 16. An aerostat according to any one of the preceding claims, which comprises from 5 to 500 internal body portions.
17. 17. An aerostat according to any one of the preceding claims, wherein each internal body portion has a dimension in the direction perpendicular to the length of the body of from 30 to 4000 cm.
18. 18. An aerostat according to any one of the preceding claims, positioned at an elevated location.
19. 19. An aerostat according to any one of the preceding claims, which comprises a tether connecting the aerostat to a substantially ground level location.
20. 20. An aerostat according to any one of the preceding claims, wherein the elongate body, when the upper end is substantially vertically positioned above the lower end in use, has a horizontal cross-section at each point throughout substantially the entire length that is an aerofoil, providing a leading edge and a trailing edge extending between the upper end and lower end, and defining between them, for each horizontal cross-section, a chord line, between the leading edge and the trailing edge of the cross-section, having a chord length.

Description

Aerostat and Method of its Manufacture Technical Field The invention relates to an aerostat having an elongate hollow body having a length defining a local axis of the body, and a method of its manufacture. Background to the invention Low latency access to mobile communications and general information services is becoming vital for economic and social well-being. The Covid Pandemic has accelerated this process. New applications (for example, autonomous driving, remote medical support) and more generally the Metaverse, require reliable, low latency and high bandwidth mobile communications. Compared with satellites, aerostat-supported platforms have several advantages, primarily because the distance from a transmitter to a receiver on Earth can be much less, with geostationary satellites typically at 36,000 km altitude and around 1000 km altitude for a “Low Earth Orbit” or LEO satellite. This relative nearness of tethered aerostat platforms can result in much stronger signals relayed to Earth and avoid the expense of rocket launches as well as providing shorter development times, and allows power and backhaul connection via the tether. Recently-developed, lightweight, very large-capacity phased array antennas have the potential to transform global mobile and fixed line connectivity e.g. by delivering cellular telephone services, including linking to the internet. This is dependent upon them being positioned appropriately, and at typically between 200m and 2500m over most geographies. Suitable tethered aerostats are therefore needed to support such antennas, that are reliable in all weathers at moderate elevations, with power and fibre optic cables as well as lighting and lightning protection being part of the tether. Such aerostats need to be situated below commercial aviation traffic, but sufficiently elevated to provide links of up to 80 km range for low population densities, up to 30 km for moderate rural densities and 5 km in urban areas. Similarly, there are a range of earth observation, meteorological data collection, and astronomical data collection systems which could substantially benefit from being supported by a suitable tethered aerostat system that is reliable in all weathers at elevations at typically between 200m and 22000m. A tethered aerostat has the potential to be far cheaper than satellite systems with similar or improved functionality: power supply and fibre optic cable links can be supported by or be an integral part of the aerostat tether, avoiding the expensive and limited backhaul systems and power systems required for satellites or aircraft. Furthermore, data latency effects are important to many applications (including but not exclusively, augmented reality, autonomous driving, health care, interactive video games, video conferencing, remote control of UAVs etc.); there are significant problems with latencies offered by satellites, even low earth orbit satellites. The need for improved mobile connectivity has prompted a resurgence of interest in using alternative delivery technologies rather than ever large numbers of mobile communication masts e.g. low earth orbit satellites, stratospheric platforms and tethered aerostats. All of these solutions have issues; respectively: data capacity and latency, technology readiness level, and wind stability. Current tethered aerostat systems include tethered rigid and non-rigid airships (blimps) and hybrid balloon/kite systems. Airship-type designs are usually inclined to the horizontal to provide both aerodynamic lift as well as buoyancy. The principle of a hybrid balloon/kite system is that the balloon provides lift in low wind speed conditions and the kite provides lift in high wind speed conditions. Hybrid balloon/kite systems are usually less expensive than airships. However, for such balloon/kite systems in high wind speed conditions the horizontal drag on the balloon is high and the kite therefore needs to be large, incurring considerable drag forces to provide sufficient lift to maintain altitude. These large drag forces then require a very strong and hence, heavy, tether, which has its own associated drag that requires a still larger balloon/kite system to support it, thus reducing payload carrying capacity. Current tethered airship designs and balloon/kite systems do not survive strong winds of more than 50 knots for smaller systems and for very large systems winds of more than 70 knots or exceptionally 100 knots. For continuous operation at useful elevations of typically over 400m, high wind speeds of over 100 knots will have to be sustained. With high winds, existing systems become unstable, moving uncontrollably and are ultimately blown over. Because of these effects it has not been possible hitherto to design and build a reliable tethered aerostat system to deliver a high availability service because very high wind conditions will be encountered almost everywhere from time to time, particularly at suitable altitudes needed for