UAS SPACE BASED SYSTEMS ON MARS
When looking at operations of UAS on Mars, we must first identify what application we are designing the system for. There are currently two operation rovers on Mars that are exploring the surface of the planet. Our company will be looking to focus on communications equipment. To talk back and forth from the earth and the surface of Mars, there has to be a bridge between the surface of both planets. Primarily this has been done to date by satellites. Communication by satellites can be good and bad at the same time. Currently, there has never been any known mission aside from the Hubble Telescope to repair or make modifications of satellites in the atmosphere. The reason for this is due to the actual altitude of the satellites. Due to the high altitude, we are unable to effectively reach the satellites for repair without attempting the utilization of remotely operated vehicles.
Looking at the fundamental problems or challenges we would face, we would need to have a renewable power source to utilize for the life of the system. Another issue would be maintaining the ability to reach the system to do maintenance or upgrade it over time. In the case of a system on Mars, it would need to have a long functional life. We are expecting technology to change as we are exploring Mars; it would greatly benefit us to have access to the UAS or bring it to the surface for upgrades. To mitigate these issues, I would like to design the aircraft like the current model of Facebook's Drone. The Facebook drone is expected to fly off batteries for long durations and recharge from the solar panels on the wings.
The challenges of a thin atmosphere on Mars is difficult to compare to the atmosphere on Earth thoroughly. Flying a drone on earth at high altitudes, we can emulate the thin atmosphere on Mars. These features allow us to test the systems to a very close degree of accuracy on Earth to make sure that it is ready for operations on Mars. One of the areas of concern is sending transmissions from the surface to a satellite and relaying back to earth. Current NASA technology called LLCD (Lunar Laser Communication Demonstration) utilizes lasers directed at the satellite and a communications ground station. "To meet these demands, NASA is moving away from their form of dial-up (radio frequency-based communication) to their version of high-speed Internet, using laser communications." (NASA, 2016) This laser communication allows for a large bandwidth for data transfer. Laser communication should be easier for Mars due to the thinner atmosphere. The renewable energy issue is also prevalent on Earth as we require satellites to utilize solar panels for power. Another problem that is similar to earth is accessing the system for maintenance or upgrades. This can be mitigated by utilizing a flying drone instead of a satellite in the atmosphere.
There won't be many differences, if any, for this system compared to Earth. Due to the similar environment and the job that it's filling, it will have almost equal similarities to earth when looking at challenges of design and problems with the system. This will allow us to have an excellent idea of the wear and tear and the actual usability of the system in a near-identical environment. One difference, however, would be the lower gravity on Mars. Lower gravity would allow for an increased payload weight compared to an earth-based system along with greater flight time due to lower power requirements to stay airborne, however, a thinner atmosphere could affect this.
Key technologies that will be needed for our communications system would be along the lines of a system that can stay aloft nearly indefinitely without intervention. "The plan is to power these drones with the sun so that they can stay aloft for months at a time. Aquila isn't yet ready for that, but Facebook says the current design can operate on the power of about three hairdryers at altitude—and about a single hairdryer at sea level." (Metz, 2016) Solar panels will be the primary renewable energy source to recharge the batteries on board. Due to the nature of the device, it would be ideal to have it positioned in the atmosphere so that it is under sunlight whenever the communications array is being used. This is due to the high electrical load that would be put on the power system whenever signals are passed between Mars and Earth. Another critical technology would be the autonomous flying of the UAS.
The software onboard would need to have an accurate location measuring to maintain specific locations. This could be a problem without a GPS type system around Mars. The software would also need to allow for complete autonomous operations of the UAS. The users may need the UAS to land by itself to receive maintenance or upgrades. Autonomous maintenance with modular systems would be the most effective if we do not have personnel on the planet.
This spaced based UAS will provide high bandwidth communications links between Mars and Earth. It will be flying in Mars' atmosphere with electrical motors while renewing its power source with solar panels. Keeping the system in the atmosphere will allow for easy maintenance and upgrades over time throughout the life of the system by allowing operators to land it. The decreased gravity on Mars would allow for a heavier payload compared to earth. It would need to be utilized in a hub and spoke type system to allow for coverage across a large distance.
References
Metz, C. (2016, July 21). Facebook's Giant Internet-Beaming Drone Finally Takes Flight. Retrieved September 08, 2016, from http://www.wired.com/2016/07/facebooks-giant-internet-beaming-drone-finally-takes-flight/
Metz, C. (2016, July 21). Figure 1: Facebook High-Altitude Drone [Digital image]. Retrieved September 8, 2016, from http://www.wired.com/2016/07/facebooks-giant-internet-beaming-drone-finally-takes-flight/
NASA. (n.d.). Lunar Laser Communications Demonstration. Retrieved September 08, 2016, from http://esc.gsfc.nasa.gov/267/271.html
Williams, M. (2016, April 06). Mars Compared to Earth - Universe Today. Retrieved September 08, 2016, from http://www.universetoday.com/22603/mars-compared-to-earth/