kotidius
commented
11 months ago By using the calculations done at issue #7 we receive the total power requirements for linear movement as 80 W in flat surface and 192 W in a maximum slope of 30 degrees. The motor currently chosen has a maximum wattage of 30 W, meaning a total of 240 watts as an absolute maximum. Also we must consider that, due to the rough surface, the motors will probably be working near their limits almost all the time, as such it is not possible for the rover to be moving linearly at all times.
I would propose that half the rovers energy should be allocated to linear movement, and the rest to be reserved for other applications. With that amount (approx. on average 2.6 KWh) the rover would be able to move for 10.83 hours under the worst circumstances and the whole day under the best. Those numbers are based on the average solar intake, so when the rover is facing a sandstorm it will simply go into hibernation until it has sufficient power.
Here are the calculations and assumptions on the rover's energy requierments
The power willl be provided exclusively by solar panels.
Mars receives only 43.1% of the solar energy per squered meter compared to earth, leading to a average solar irradiance of 590 Watts/m2.
The higher-end solar panels currently used on space applications have an average efficiency of 30% and maximum output power of 400 W/m2 according to this paper published by nasa.
The solar panels used on nasa's opportunity rover, had a maximum power output (pmp) of 140W, a total area of 1.33m2 and at the start of the mission produced on average of 900 watthours per sol. Using that information we can calculate that, on average, solar panels on mars produce their pmp for 6.5 hours/sol.
The current design will host approx. 4 sq. meters of solar panels
The total energy intake will be (panel surface)(daily hours of pmp)(pmp) = 4006.54 = 10.4 KWh/sol
The number is significantly higher than opportunity's 0.9 KWh/sol but the difference comes from the fact that our array has three times the surface as well as more than 20 years of advancements into solar panel technology.
The data provided by nasa on the power characteristics of their rover reveal that after some time into their mission the total energy intake was reduced by more than 30% and by the end it had been reduced by more than 50%. Considering this it would be wise to calculate the rovers energy requirement by using half the above mentioned number. As such the rover will be expected to produce on average 5.2 KWh/sol if we continue with those characteristics.