73
votes
Accepted
Why don't we shield existing CPUs from radiation instead of designing new ones?
Because shielding against radiation is heavy, and weight is the enemy of getting things into space.
CPUs are quite sensitive to radiation, and some types of radiation (cosmic rays) are not only quite ...
- 3,382
68
votes
How did Apollo missions solve the cosmic radiation problem?
While cosmic radiation is a problem, it's the same as with radiation on Earth: the risk is cumulative. The levels were low enough that missions of 1-2 weeks at this level did not pose a big health ...
- 123k
66
votes
Accepted
Why can't we use the same radiation shielding in Mars that we used when going to the moon?
Radiation exposure is a cumulative risk. The more radiation you receive, the more likely you are to develop cancers.
The Apollo missions took no more than two weeks to complete; the astronauts ...
- 164k
66
votes
Why can't we use the same radiation shielding in Mars that we used when going to the moon?
In addition to what Russell Borogove says about cumulative risk you're operating under a false assumption--that there was shielding on the Apollo capsules.
Not only did the Apollo capsules not have ...
- 11.2k
60
votes
Accepted
Can we power things (like cars or similar rovers) on earth in the same way Perseverance generates power?
RTG technology has been applied on Earth, many times, although not for transportation - they don't produce much power for their weight so any RTG powered vehicle would be very slow. Some pacemakers ...
- 19.2k
54
votes
How did Apollo missions solve the cosmic radiation problem?
They didn't, which is why the Apollo astronauts saw blinding flashes inside their eyes during the mission and then had a much higher probability of suffering from cataracts later in life.
The flashes ...
- 821
50
votes
How did the Apollo guidance computers deal with radiation?
TL;DR: It was so busy getting stuff done, it didn't care.
Being old, slow, massive and inefficient (by any modern standards, not by those in 1965) is a huge benefit when it comes to radiation hardness....
- 14.3k
48
votes
How did Apollo missions solve the cosmic radiation problem?
Apollo solved the cosmic radiation problem in a counter-intuitive manner: by minimizing shielding.
Most cosmic rays are very-high-energy atomic nuclei; the rest are very-high-energy protons. When ...
- 12.4k
38
votes
Accepted
How was it possible for the Apollo 11 to film and take pictures with such radiation?
The radiation dosage for a year on the moon is between 110 mSv and 380 mSv. On Earth, that dosage is 2.4 mSv, or higher, depending on where you are exactly. Bottom line, the few days in Lunar orbit ...
- 120k
29
votes
Can we power things (like cars or similar rovers) on earth in the same way Perseverance generates power?
RTGs are expensive to produce, can be politically inconvenient to use, and in the form of a plutonium-bearing device, represent a potential nuclear proliferation hazard (though all RTGs might be used ...
- 7,404
27
votes
Accepted
How does steel deteriorate in translunar space?
The spectral data came from the surface of the material only a few atoms thick which is exposed to hard vacuum. The solar wind has ions of many materials. It is mostly hydrogen, which as an ion is ...
26
votes
Accepted
How much UV radiation will Mars inhabitants receive?
tl;dr: The UV index is primarily concerned with the level of UV-A that can cause sunburn and, potentially, skin cancer. The actual UV-A flux at Mars is not dramatically different from that at Earth (...
- 2,601
25
votes
If colonists burrowed far enough under the ice on Ganymede or Europa, would the ice provide adequate protection for them from Jupiter's radiation?
Yes, it absolutely would! The radiation on Europa is about 5.4 Sv (540 rem) of radiation per day. Looking at this guide, and assuming you want to meet OSHA standards of 5 rem per year, you would need ...
- 120k
24
votes
Accepted
Does Curiosity pose a radiation hazard for would be colonists?
At first glance, the RTG does not pose a risk.
It is powered by Pu-238, which is primarily an alpha emitter throughout its decay chain. Alpha particles can be stopped by a sheet of paper. An ...
- 123k
21
votes
How was it possible for the Apollo 11 to film and take pictures with such radiation?
Radiation can affect film - but bear in mind the radiation around Chernobyl was, truly, extremely high. The radiation in our region of space is not as extreme.
Also bear in mind that the earlier ...
- 5,168
21
votes
Accepted
Can we survive Van Allen belt radiation?
A satellite shielded by 3 mm of aluminium in an elliptic orbit (200 by 20,000 miles (320 by 32,190 km)) passing the radiation belts will receive about 2,500 rem (25 Sv) per year (for comparison, a ...
- 1,010
19
votes
Accepted
Did the Apollo missions fly "over the top" of the Van Allen radiation belts?
Not exactly "over the top" (still through the outer portion of the belts), but yes, it appears so, according to this source.
There are simplified trajectory plots shown in the link.
Also this source
...
- 6,262
18
votes
Accepted
Do astronauts only perform spacewalks while the ISS is on the night side of the Earth?
No. Most International Space Station (ISS) spacewalks last in the order of several hours, often up to 8 hours during more difficult and time-consuming repairs and installations, and some nearly 9 ...
- 76.1k
18
votes
How was it possible for the Apollo 11 to film and take pictures with such radiation?
NASA studied the effects of radiation on film. Bright spots are just one of the possible results. Other effects include an increase in the amount of noise, and a decrease in contrast and color ...
- 123k
18
votes
How does steel deteriorate in translunar space?
Light interacts with fresh metal surfaces in only the first few atomic layers. What makes metals "metals" is the very high electron density, and we can think of that electron "plasma&...
- 149k
18
votes
Accepted
What makes Insight's RAD750 processor so radiation resistant? (compared to 1998 iMac's PowerPC 750)
(Sorry that I am not an insider, but I did spend a half-day working on this answer.)
Various versions of the iMac G3 used the PowerPC 750, 750CX, and 750CXe. The RAD750 comes in two versions: "...
- 47.3k
17
votes
Accepted
Would a nuclear propelled spaceship still need a storm shelter?
The basic idea here is to turn to have the shield you have towards the Sun. That does actually work, because the radiation from the Sun is directed, with a few exceptions: First, inside a planetary ...
17
votes
Accepted
How does ISS protect astronauts from Coronal Mass Ejections?
The two specific modules are protected by two mechanisms:
TeSS Polyethylene radiation protection tiles and bricks
Water storage bags attached to the walls making a "water wall"
High densities of ...
- 6,143
16
votes
How big is the risk/potential damage from radiation on a Mars trip?
If you just stay here on Earth, you have an 18% chance of dying of cancer. Let's first consider a one-way trip, ignoring solar flares and radiation after you land. So just consider the cosmic rays, ...
- 58.2k
16
votes
Accepted
Could ozone be used in a biodome on Mars?
If we have $O_2$ lighted with UV, we have actually many reactions working together:
$O_2 + \gamma \rightarrow 2O$
$O_2 + O \rightarrow O_3$
$O_3 + \gamma \rightarrow O_2 + O$
$O + O_3 \rightarrow 2 ...
- 3,258
15
votes
How did the first US manned Moon mission suits block radiation?
The Van Allen belt radiation was primarily shielded by the hull of the spacecraft, not the space suits. The electrons were mostly absorbed by the aluminium. Of the protons, however, some would ...
- 1,686
14
votes
What materials provide the best protection from cosmic radiation?
With respect to potential travel in our own solar system there are two general types of radiation that have our concern!
The first type of radiation is solar radiation, which mostly consists of low- ...
- 494
14
votes
Can we survive Van Allen belt radiation?
No, it is not impossible. 9 Apollo missions sent humans through the Van Allen belts, and the astronauts survived just fine.
The radiation levels in the Van Allen belts are high, about 1000 times ...
- 120k
14
votes
Why don't we shield existing CPUs from radiation instead of designing new ones?
You actually ask a really good question. And the answer is, we do both, depending on the needs.
NASA tends to go for the ultra-reliable, and radiation tolerant components are more reliable, thus it ...
- 120k
13
votes
Accepted
Influence of solar wind and radiation pressure on a sail
According to wikipedia, solar wind pressure at 1AU is about 1-6 nN/m2. Solar light pressure on the other hand is apparently 4.54-9.08 μN/m2. It therefore seems unlikely that solar wind pressure will ...
- 7,404
Only top scored, non community-wiki answers of a minimum length are eligible