Challenges for the development of Manned Deep-Diving Vehicles

In its Deepsea Challenger, James Cameron and his team, pushed forward the development of the Manned Deep-Diving Vehicles by placing this vehicle in the deepest local on Earth, at 11 kilometers on the Mariana Trench. Still, there are a large number of developments to be performed. Here is our list of challenges regarding the Manned Deep-Diving Vehicles:
• Sphere Diameter – The pressure sphere of the Deepsea Challenger had 1090 millimeters of diameter and for that reason was only able to transport only one person. One step further should be, increase the diameter of the spheres in order to carry more humans in each travel. The research of lighter alloys, but also more resistant to the compression forces must be a priority;
• Energy – It would be useful to increase the efficiency and the capacity of the vehicles to store energy, in order to increase the capacity to expend more time in deep waters. During the submersion and the emersion there are physical and chemical variables that can be used to produce energy, for instance the variation of temperature, salinity or the potential energy.
• Thrusters – The increase of the capacity to store energy will allow the possibility of implementing thrusters that can expand the area of exploration in deep-sea;
• Communications – The systems used in the deep-sea communications are not reliable and for that reason work must be done to optimize the already existing systems ;
• Safety and Reliability – The deep-sea vehicles are still not taken as reliable devices. In order to change this vision is necessary to continue the development and optimization of the existing technologies and proceed with the deep-sea exploration by increasing the number of vehicles sent to deep waters.

Which are your thought related to this? Do you find other challenges? Is the space sector helpful to provide knowledge in order to overcome some of these challenges?