My Little Pony: My Little Pony The Martian

Mission Log – Solar Day 418

It has been a while since I last wrote a diary, but I have been very busy recently, such as tracking down leaks in the mobile home, helping with pre-trip physical examinations, and many other miscellaneous preparations. So I have to lay out a lot of backstory before I can tell how I got to where I am now (i.e., returning to the living quarters after another round of Sirius 7 attempts).

The dissipation of the clouds and the clearing of the sky again really helped a lot - but as a result, the temperature inside the mobile home has also dropped significantly at night. The RTG and thermal insulation materials arranged in the living cabin can relatively alleviate the problem of insufficient heat. However, when we woke up this morning, we were huddled together, and we all clearly remember that everyone definitely did not fall asleep in this position. I can tell you for sure that getting up and putting on a spacesuit in an ice cellar-like cabin is not a great experience. But it wasn’t cold enough to cause serious discomfort yet, so we decided to endure it for now.

I have spent the past week observing the power output of my solar panels at noon. On Solar Day 410, there was still sufficient cloud coverage, and the solar panel I tested had an output of 108 watts at noon. On today's solar day 418, when the sky is completely clear with only the usual layer of pink haze, the measured power is 122 watts. This is excellent news. As long as this climate can be maintained, our charging efficiency can be maximized.

During this week, we also checked the electrical system of the mobile home from start to finish twice, and also checked the system of the No. 2 rover. The result was that we found four exposed conductors on the cable, and one wire was completely broken (obviously connected to an abandoned system); in addition, we also completely dismantled four bundles of wire bundles that had completely lost their function. . But we didn't just throw them away; the removed cables were placed in a scrap material and tool storage area at the rear of Rover 2. There are so many potential uses for these cables that I wouldn't want to just throw them away unless absolutely necessary.

In addition to this major inspection, we also double-checked that the stumps of cut cables left in the cabin were correctly de-energized and fully insulated; we have tried our best without dismantling the Pony spacecraft. We have done everything we can to protect the safety of the entire spacecraft circuit. "No dismantling" here of course refers to "no further dismantling". This thing now looks like it has been ravaged by various scavengers in a recycling bin for six months.

Then we finally got to the point where we could carry out the two tests of Sirius 10's second mission. Yesterday, after being fully charged, we set off from the residential area an hour before dawn. Before departure, we also disconnected the access cables of the solar panels on the roof of the trailer, so that only the RTG was still inputting energy into the power system during the journey. As for the other remaining devices, they are naturally consuming power all the time. We drove all the way until the battery indicator showed 850%, which meant that we consumed almost a watt-hour of power. As for the distance traveled: a total of fifty-seven and one-ninths of a kilometer, so the power consumption rate drops to watt hours per kilometer. This should be due to the power loopholes we have worked so hard to plug.

We reconnected the solar panels, rolled out the extra ones on Rover 1, and pretty much went about the same routine as before. Four days' worth of potatoes were pre-cooked before we left, so each potato meal only took about four minutes to go from frozen to ready to eat. (Another thought suddenly occurred to me; if we took the potatoes out of the saddlebags for the next day in advance every day and thawed them, this time could even be cut in half.) As for other aspects of life, our behavior is It's exactly the same as before - tinkering with the computer, chatting and reading, charging the space suit, that sort of thing. When we woke up this morning, the battery reading was less than % away from being fully charged.

Well done to the team members! The operation to protect the pirate ninja was a great success!

So this leads to the experiment to be carried out today; driving back along the original road, disconnecting the solar panels again on the way - which means that the conditions during the driving process are basically the same as before - but the difference is that this time the No. 2 rover The motor clutches of the two rear wheels are disengaged.

Let me explain the logic behind this experiment. The motor system that drives the rover wheels is designed to operate at a relatively low speed, but it can produce astonishing amounts of torque. You may remember that Rover 2 was able to drag the entire wreckage of the Pony spacecraft with its own propulsion power - a weight two and a half times its own weight. (Okay, it’s unfair to say that; in fact, it was not dragged by its own power. We also had a unicorn and a dragon on hand to help the spacecraft cross the ravine terrain. But if the flatness of the ground here and the orbit If the conditions observed above are consistent, this weight can definitely be towed. Not to mention that if the ponies used a larger wheel pair in the landing gear design, the towing speed would not be as slow as a crawl. That’s a thousand meters an hour. I’m not exaggerating; the Ares rovers are some incredibly strong monsters.)

The current thinking is that the motor's drag efficiency envelope should be smooth; that is to say, as long as the load is not zero, or it is so heavy that the motor cannot move at all, it should run near the peak efficiency, so no matter It shouldn't make any difference whether you give all the power to the same motor or distribute it evenly across four or eight motor heads. However, this is not the case at all. In fact, as long as the load endured by a motor drops below 50% of its rated load, the operating efficiency will also decline. If it's below 20%, it's basically useless.

The reason is friction. Friction constantly steals the efficiency of any kind of powered engine—bearings scraping against each other, sliding against the casing, etc., in various ways that add up. It is true that reducing the load will indeed reduce the electric energy required for dragging...but the consumption of friction is eternal, so the proportion of electric power lost in the form of friction in the total energy consumption will be rise.

Going back to what I just said, the motors in each rover wheel are not fuel-efficient. NASA's need at the time was to design a highly energy-efficient rover, but they also hoped that the final vehicle could climb over rugged and harsh terrain and carry the team back safely. After all, this was the top priority. However, the group of people with cerebral palsy who had previously made such failures as safety glass helmet visors and disposable carbon dioxide filters thought this time, "What does it mean to overdo it? It doesn't exist." So the final result is something that can almost bring England down. The island group is dragged directly across the Channel all the way to the terrible motor that borders France.

I'm exaggerating here, but the key point I want to express is that the traction capacity of the rover's drive motor is definitely too strong. It is naturally a good thing to have such strong power when starting out with a load of twenty-six tons, but once the vehicle starts moving, the energy consumption to maintain forward movement is actually very little. At this point, the apparent load drops off a cliff, and friction - further exacerbated by excessive overloading of the mobile home - quickly swallows up operating efficiency. And even if we let the computer send instructions to those motors to cut off power, it will not help, because the result is that the powered off motor will immediately become a generator, and the large amount of resistance generated will only drag down other running motors, even if it can produce A little electrical energy is far from enough to make up for the huge efficiency loss.