I asked this before but I couldn't find the thread. What is an acceptable power to weight ratio for a fission reactor for a spacecraft? If possibly we had a fusion reactor for a spacecraft, what might its power to weight ratio be?
I asked this before but I couldn't find the thread. What is an acceptable power to weight ratio for a fission reactor for a spacecraft? If possibly we had a fusion reactor for a spacecraft, what might its power to weight ratio be?
What has flown has been pretty terrible, around 200-600 kg/kW for SNAP-10 and some of the old Soviet designs. The SP-100 was supposed to be about 50 kg/KW. All of those have been very low efficiency, however, and there are credible designs for maybe 1 kg/kW.
As for fusion, no one knows, and anyone saying differently is selling something.
I was wondering about power generation on Mars itself. Could a small wind turbine be used on Mars to generate electricity in conjunction with solar?
I work in the Wind industry and it just occurred to me. Since Mars has winds it might be possible. But the thin atmosphere and pressure may negate it. I just don't have enough information to even do a mini analysis.
Aeroman
I was wondering about power generation on Mars itself. Could a small wind turbine be used on Mars to generate electricity in conjunction with solar?
I work in the Wind industry and it just occurred to me. Since Mars has winds it might be possible. But the thin atmosphere and pressure may negate it. I just don't have enough information to even do a mini analysis.
Aeroman
Mar's atmospheric pressure ranges from 30 - 1100 pascals with a mean surface pressure of ~600 pascals, while earths pressure at sea level is about 101 kPa (or 101,000 pascals).
Solar is a better option. Not enough air mass to really push a wind turbine around.
Take a glance at the significant differences:
http://en.wikipedia.org/wiki/Atmosphere_of_Marshttp://en.wikipedia.org/wiki/Atmospheric_pressure
I was wondering about power generation on Mars itself. Could a small wind turbine be used on Mars to generate electricity in conjunction with solar?
I work in the Wind industry and it just occurred to me. Since Mars has winds it might be possible. But the thin atmosphere and pressure may negate it. I just don't have enough information to even do a mini analysis.
Aeroman
I was curious about this question as well, and found this paper on the subject:
Performance and Feasibility Analysis of a Wind Turbine Power System for Use on MarsNASA/TM-1999-209390 September 1999, 10 pages
Abstract
A wind turbine power system for future missions to the Martian surface was studied for performance and feasibility. A C++ program was developed from existing FORTRAN code to analyze the power capabilities of wind turbines under different environments and design philosophies. Power output, efficiency, torque, thrust, and other performance criteria could be computed given design geometries, atmospheric conditions, and airfoil behavior. After reviewing performance of such a wind turbine, a conceptual system design was modeled to evaluate feasibility. More analysis code was developed to study and optimize the overall structural design. Findings of this preliminary study show that turbine power output on Mars could be as high as several hundred kilowatts. The optimized conceptual design examined here would have a power output of 104 kW, total mass of 1910 kg, and specific power of 54.6 W/kg.Interestingly this is what it has to say about the comparison of Earth and Mars:
"The atmosphere of Mars is very different from that on Earth. The pressure and density of Mars's atmosphere is about one percent that of Earth's atmosphere. However, wind speeds can be up to five times faster on Mars than on Earth. These two phenomena counteract each other when affecting power output, as can be seen by Eq. 1. The net effect is that power output on Mars is roughly comparable to that on Earth.
Unfortunately, wind speeds capable of providing this high level of energy exist only at around 7 to 10 km altitude in the Martian atmosphere ..."Equation 1 P = ½ ηρAV
3η - turbine efficiency
ρ - air density
A - frontal area of turbine
V - wind speed
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19990081125_1999123906.pdf