Comments on: German instrument on Chang’e-4 documents dangerous radiation levels

By: Steve Richter

Steve Richter — Mon, 28 Sep 2020 19:40:38 +0000

“… I’ve always wanted to see an analysis comparing human to robotic exploration under the assumption that they are given the same budget. …”

what gets more work done, a human on a rover with space suit, oxygen, food, water, living space, instrument panel, chair – or two remotely controlled rovers, earth mover, 3d printer and power plant? Heck, half the power and space on the rover is needed for the human. And the robot stuff works for years while human can’t stay for very long.

How is modern manufacturing done if not by machine? Oil and gas exploration is done from cubicles in Houston. Commercial jet liners are automated. Even interstate trucks are soon ready to drive themselves.

Is China planning to send humans or machines to the moon?

By: Max

Max — Mon, 28 Sep 2020 19:28:15 +0000

These readings are interesting because it could be used as a baseline during solar minimum.
The minimum exposure they can expect.
But what if the astronauts are exposed to a proton storm during an active phase of the sun?
A solar explosion the equivalent of 100 billion hydrogen bombs. In 2005,
“The Jan. 20 proton storm was by some measures the biggest since 1989. It was particularly rich in high-speed protons packing more than 100 million electron volts (100 MeV) of energy. Such protons can burrow through 11 centimeters of water. A thin-skinned spacesuit would have offered little resistance”
https://www.nasa.gov/mission_pages/stereo/news/stereo_astronauts.html

“Inside earths magnetic field, the astronauts on the ISS received about one rem of radiation, equal to one series of x-ray at the doctors office.”

“On the moon, an astronaut protected by no more than a space suit would have absorbed about 50 rem of ionizing radiation. That’s enough to cause radiation sickness. “But it would not have been fatal,” he adds.
To die, you’d need to suddenly absorb 300 rem or more.”

I still maintain that the best shielding, is the same that is used around nuclear reactors. Water.
In space, the mass of spent boosters would offer additional effective shielding in a pinch. An artificial magnetic field triggered buy a surge in radiation is effective also (especially in “extensive exposure” such as a trip to Mars)

The best shielding is underground… but for the surface, a lunar rover with tinted glass similar to a welding helmet will reduce the radiation considerably and is practical.

By: Marcus

Marcus — Mon, 28 Sep 2020 14:48:20 +0000

I’ve always wanted to see an analysis comparing human to robotic exploration under the assumption that they are given the same budget. As far as I can tell, human exploration isn’t possible at the budgets we are currently allocating to robotic exploration. Also, we never really consider what we could do with robots if given the same budget required for human exploration (I guess I mean I haven’t seen that). It’s just not clear to me which would win. For fun, I’m going to speculate that for the moon it might be close, but for Mars, robots would win hands down.

I also agree that robots shouldn’t be allowed to have all the fun, and robots can never be a substitute for human settlement. :)

By: Calvin Dodge

Calvin Dodge — Sun, 27 Sep 2020 13:44:22 +0000

This doesn’t bode well for astronauts in FLOP-G. I think they would experience higher levels of radiation, since they won’t have the Moon blocking cosmic radiation on one side.

By: Vincent

Vincent — Sun, 27 Sep 2020 08:01:27 +0000

60 microsievert per hour is 6 millirem per hour, which is not a lot. At my power plant, areas with that level of radiation are routine to access, and an ordinary concrete wall brings the level to less than 1 mrem/hr. However I imagine it’s possible that high-energy cosmic rays might require thicker shielding to achieve the same effect, I’m not an expert on radiation. Regardless this level of radiation would be quite unconcerning to me to work under for hours and cumulative days and weeks per year. It seems a non issue besides requiring long-term structures to be a few feet underground, which is already a good idea to protect against micrometeorites.

By: Robert Zimmerman

Robert Zimmerman — Sun, 27 Sep 2020 06:22:58 +0000

In reply to Tom Billings. And as I always say, why should robots have all the fun?

By: Tom Billings

Tom Billings — Sun, 27 Sep 2020 05:39:53 +0000

Steve Richter asked:

“What can humans do on the Moon that remotely controlled, semi autonomous machines cannot? ”

The answer is, they can become a human settlement of the Moon.

In addition, they can use lunar resources to build the machines, that build the machines, that can make it far cheaper to build that settlement.

They can explore lava tube caves on the Moon, and come out to tell us about them. They can then build settlements inside those caves, so that they, and their machines, can have a place away from the abrasive dust of the lunar surface, and the radiation, and the rapid variation between the heat on one side of the terminator, and the cold on the other side. They can build the mirrors that can light the caves during daylight, and the power receivers to light them during the 2 months of darkness from power beamed from either the EML#1 point, or otherwise the EML#2 point.

By: LocalFluff

LocalFluff — Sun, 27 Sep 2020 00:29:36 +0000

Human space flight is probably even safer that robotic! Because of all the thousands of people who manage the robots, some will electrocute themselves or fall out of the window, or die in a car crash on the way to the office where they spend decades to do what one man on site could do in a few days.

By: LocalFluff

LocalFluff — Sun, 27 Sep 2020 00:16:29 +0000

@Steve Richter
Like Edward wrote, humans are more productive. But EXTREMELY more productive! One geologist on Mars would do in a couple of days what the curiosity rover has done in almost a decade. Insight has spent almost two years to try getting its little drill into the ground, and still hasn’t gotten to useful depth. The moonwalkers could drill 9 feet in a few minutes. Robots are almost completely useless. But for a few billion dollar and a decade, they can barely achieve a minimum result, which is valuable because it is all the science we get. At least if nothing goes wrong, because there’s no way to fix any kind of problem. Human space flight is even much more economical that robotic. A human mission to Mars would accomplish more than 100 robotic orbiters and landers.

By: Edward

Edward — Sat, 26 Sep 2020 20:40:08 +0000

Steve Richter asked: “What can humans do on the Moon that remotely controlled, semi autonomous machines cannot?

Humans are more productive. They work faster, can see more, and make better decisions on the spot.

By: Steve Richter

Steve Richter — Sat, 26 Sep 2020 17:12:18 +0000

What can humans do on the Moon that remotely controlled, semi autonomous machines cannot? Especially considering that for every human and their support gear on the space craft, many machines will not be able to make the trip. And the machines – rovers, earth movers, drillers, solar arrays, power plants, telescopes, computers, communications gear – continue to work long after the humans have returned to Earth.

By: Phill O

Phill O — Sat, 26 Sep 2020 00:13:28 +0000

The radiation data monitored over a full year would be informative.

Madrocketsci You are correct that we really do not have a good handle on how much radiation we can take. Technicians working on our Slowpoke reactor were permitted 10 times more than we were permitted.

By: Madrocketsci

Madrocketsci — Fri, 25 Sep 2020 23:09:07 +0000

We still dont have a good handle on how much radiation humans can really handle. We use linear no threshhold extrapolations from fatal acute dose accidents. If linear no threshhold were true, however, we would never heal from a sunburn. We know its ludicrously conservative, just not by how much.