The 14.5 billion dollar willpower Rover uses the CPU of 23 years ago

NASA's perseverance successfully landed on the surface of Mars, took over the curiosity Rover and continued to explore the evidence of life on Mars.
For the $2.7 billion (about 17.5 billion yuan) willpower, it not only uses aerial crane landing technology, has nuclear power, but also carries very advanced instruments.
However, surprisingly, the core processor rad750 of willpower actually adopts the same architecture as the built-in processor of Apple IMAC G3 in 1998 - PowerPC 750.


The 14.5 billion dollar willpower Rover uses the CPU of 23 years ago? The main frequency is only 200MHz
According to the data, the dominant frequency of PowerPC 750 is only 233MHz, integrating 6 million transistors, and its performance is very limited.
Obviously, for the $2.7 billion willpower, the cost of choosing a processor is certainly not an important factor. So why not choose the processor architecture more than 20 years ago instead of more powerful processors?
The key reason is that the thickness of the Martian atmosphere is only one percent of that of the earth, and its blocking effect on radiation and charged particles is far less than that of the earth. Therefore, the more complex the processor is, the higher the probability of error of its electronic components will be.
In fact, both the willpower Rover and the curiosity Rover nine years ago use processors based on the PowerPC 750 architecture, but the rad750 processor on the willpower rover is different from the processor used by IMAC more than 20 years ago.
It is reported that the processor is manufactured by BAE Systems Using 0.25um or 0.15um process, with a chip area of 130 square mm, 10.4 million transistors and an operating frequency of 200MHz.
In addition, in order to deal with the influence of cosmic radiation, severe high and low temperature and other factors, rad750 has undergone special treatment.
The CPU itself can withstand 200000 to 1000000 rads in the temperature range of - 55 ℃ to 125 ° C.
At the same time, it also has 2GB memory and 256MB ram. It is reported that the cost of such a calculation module is as high as 200000 US dollars (about 1.3 million yuan).
The report explained that the unit price of willpower's PowerPC 750 processor is so expensive, not because of its super high performance, but because it has to cope with the unknown space environment, so it has to strengthen the anti radiation, cold resistance and other functions of the processor.
Although the architecture of this processor is still the same, it is not a mass-produced processor because of its high price due to its structure enhancement and optimization.
Although the performance of rad750 is not worth mentioning compared with the CPU on modern smart phones or PCs, compared with the rad6000 processor on spirit and opportunity, the running frequency of rad750 is increased by 10 times, and the flash memory capacity is increased by 8 times.
In addition to the willpower and curiosity rovers, rad750 is also used in the Fermi space telescope, the lunar exploration orbiter, the comet probe deep impact and the Kepler telescope.
In order to deal with the problem that willpower may have processor failure on Mars, willpower is equipped with three sets of computing modules, one for processor, one for image analysis and one for standby.
The key instruments and equipment of willpower are as follows:
The 14.5 billion dollar willpower Rover uses the CPU of 23 years ago? The main frequency is only 200MHz
1. Mastcam-z: This is a zoom panoramic camera on the mast, which can produce high-resolution panoramic and three-dimensional images; it can identify the composition of rocks on the surface of Mars, and it can also assist the rover to move. It consumes about 17.4 watts of power.
2. Supercam: This is a laser ultra distance analyzer, which can use high-definition cameras, lasers and spectrometers to analyze the composition of rocks and soil on Mars from a long distance. It consumes about 17.9 watts of power.
3. Pixl: This is an X-ray spectrometer, which can use the principle of X-ray fluorescence produced by minerals for more accurate analysis. Equipped with a macro camera, it can see very fine Martian sand. It consumes about 25 watts of power.
4. Sherloc: This is an ultraviolet spectrometer that can use ultraviolet laser to analyze minerals and organic matter. It will be the first ultraviolet Raman spectrometer on Mars. The instrument is also equipped with a high resolution color camera. The total power consumption is about 48.8 watts.
5. Moxie: we know that 95 percent of the Martian atmosphere is carbon dioxide. This instrument will carry out a very important experiment, which is to produce oxygen from carbon dioxide in Martian atmosphere by chemical reaction. With oxygen, it can not only be used by astronauts landing on Mars in the future, but also the propellant of rockets. This instrument consumes about 300 watts of power.
6. MEDA: equivalent to a mobile weather station, it can record the temperature, pressure, wind speed, wind direction, relative humidity and the size and shape of dust in the Martian atmosphere. It consumes about 17 watts of power.
7. Rimfax: This is a radar detector. This instrument uses radar to detect the geological structure under the surface of Mars. It can achieve centimeter resolution. It consumes about 5 to 10 watts of power.
8. Smart helicopter: during the Mars exploration, willpower also carried a small helicopter named ingenuity for the first time, which can survey some areas difficult for willpower to reach.
The 14.5 billion dollar willpower Rover uses the CPU of 23 years ago? The main frequency is only 200MHz
The helicopter weighs only 1.8kg, is 0.5m high and has a propeller diameter of 1.2m. It is lifted by two counter rotating propellers with a power of 350W.
Although the surface gravity of Mars is only one third of that of the earth, which is conducive to the flight of spacecraft, the air pressure of Mars is only 1% of that of the earth, and the air is very thin, so it requires the propeller to rotate faster. Small smart helicopter propeller rotation angular speed up to 2400 rpm. The horizontal speed is 10 meters per second and the climbing speed is 3 meters per second.
The helicopter is recharged by solar panels on the top, and the power is stored in lithium-ion batteries. Charging a day, about 90 seconds to fly! A color camera and a black and white camera are installed.
This helicopter can't directly contact with the earth, so it has to relay information through the willpower. Therefore, it can't fly too far away from the willpower. The farthest range is only 300 meters, and the farthest communication distance is 1 km.
In fact, the Mars helicopter project is mainly for technical verification, and has not given too many missions. The resolution of Mars helicopter is higher than that of orbiting satellite, and it is more flexible and maneuverable than Mars rover. Once the flight is successful, it will add a new way to Mars exploration in the future.