32

Looks pretty darned quiet to me right now: You can find that here, along with other measures of space weather. By the way, cosmic rays and solar activity are two entirely different things. Cosmic rays originate from outside of our solar system. The flux of cosmic rays is relatively constant. As for your question about stress, indeed, I just experienced ...


22

This answers the question on how to block ions coming directly from the Sun from hitting Mars by a satellite stationed at L1. It does not cover the fact whether such a shield is effective in reducing the radiation level on Mars surface. See e.g. here for more details on radiation. First, let's have a look at the magnetic field needed. Inside a magnetic ...


18

The mass of Mars is so small, and its magnetic field so weak that it cannot hold onto carbon for a long period of time, making almost all of it to escape. (Venus and Earth are close to identical in size, Mars is much smaller) Venus does not really leak that much of its atmosphere, the only noticeable exception is that all hydrogen compounds are virtually ...


17

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 magnetosphere, charged particles are bent, and form radiation belts, for example the Van Allen belts. There, shielding is a bit more difficult. Secondly, that is ...


12

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 make up a substantial proportion of the sail's thrust. The solar wind is generally a mix of electrons, protons and alpha particles with energies of (say) 1-...


10

Yes, the ARTEMIS satellite monitors the lunar surface (a link to mission data). The lunar surface gets ionized by the plasma, cosmic rays, and coronal mass ejections from the Sun. Solar System Exploration Division, NASA Goddard Space Flight Center and Space Sciences Laboratory, University of California paper on Lunar surface charging: Magnitude and ...


9

The heat shield (TPS) is not meant to protect the spacecraft from dust impacts. The statement is not quite accurate and (from a recent search) seems to have been removed from site. As an engineer on the Parker Solar Probe team, I have been involved in the Preliminary and Critical Design Reviews for the mission which include presentations on Dust Protection ...


8

The problem is that you have to go from low-speed regime in the atmosphere (the balloon), to a high-speed regime out of the atmosphere (~7000m/s). The low forces available from a solar sail don't allow this to happen quickly enough. At an intermediate speed it is either destroyed by forces from interacting with the atmosphere or it is insufficiently ...


7

TL;DR: It wouldn't work, because you wouldn't be able to keep the comet at L1. The collinear Lagrangian points (L1, L2, and L3) are unstable; if a body were to be placed at one of these points, any perturbation - no matter how small - will move the body away from the point, at which point gravitational and/or centrifugal forces will move the body further ...


7

You need 1000km of altitude to break even between air drag and light pressure of sunlight. Below that the solar sail acts as a parachute, dragging against the remains of the atmosphere. You must reach 1000km altitude by other means. Definitely not a balloon, and not an orbital gun. Also, solar wind (protons and ions) accounts for about 0.5% of "thrust" ...


6

This looks like a good read if your really interested in the subject but the simple answer appears to be that the ionosphere of Venus is strong enough to sufficiently deflect the solar wind, without the need of a strong magnetic field. Although this doesn't completely protect the planet, Venus still looses some of it's atmosphere into space.


6

Radiation As you have rightly noted, a long cylinder pointing end on to the radiation source (probably the sun, especially during periods of high activity), can be shielded by a smaller, and thus lighter, shield. On the other hand if you need shielding facing all directions, then a sphere is a better choice. (Micro-)meteorites The spaceship is moving ...


6

I think there are a few misconceptions to clarify here: Rotating bodies can generate lift. This is known as the Magnus effect. Lift is a hydrodynamical phenomenon: Differences in flow velocity above and below a moving body translate into pressure differences which heave the body up. However in very rarified gases this mechanism stops working. This is ...


5

You have to worry about the solar wind - the charged particles that are emitted by the Sun, and which are quite effectively shielded by the Earth's magnetic field. The magnetic field of Mercury is very weak (150x weaker than Earth's), and probably wouldn't do a very good job deflecting the solar wind. See details here. It also has negligible atmosphere (low ...


5

The very idea was proposed earlier this month at the Planetary Science Vision 2050 Workshop. The talk was titled: "A Future Mars Environment for Science and Exploration", J. Green, R. Bamford, et. al. They combined heliophysics simulation tools with a Mars global climate model to do the simulation. Their abstract suggests placing a 1-2 Tesla dipole at L1 ...


5

The speed of sound in space has multiple meanings because space is not a vacuum (though the number density of Earth's magnetosphere can be ~6-12 orders of magnitude more tenuous than the best vacuums produced in labs), it is full of ionized particles, neutral and charged dust. In the interplanetary medium or IPM, there are five relevant speeds that can all ...


5

Of course it affects the probes, as the number and energy of the elementary particles increase as we get higher from the earth in general (even airplanes get higher dose of radiation than cars) and when we pass the outer layers of the earth's atmosphere in specific. Major Engineering conferences take place to discuss this issue, that's why your question is ...


5

..the heliosphere's longest span is at least 10 times as long as its shortest span Hundreds of times longer. The graphic fairly closely matches this peer-reviewed plot with actual numbers instead of eye-candy textures. The termination shock stretches "downwind" twice as far as upwind. The heliopause stretches much farther downwind, but although it's not ...


5

Research from 2017 indicates that the image may not be realistic. Recent analysis of Voyager, IBEX (Interstellar Boundary Explorer) and, somewhat surprisingly, Cassini data, seems to indicate that the heliosphere is more like a symmetric bubble. New data from NASA’s Cassini mission, combined with measurements from the two Voyager spacecraft and NASA’s ...


4

You need both a source and a sink to produce electric current by electromagnetic induction, otherwise you're really just a target at the mercy of the incoming energy discharge. So if you're going to have large static collectors in the way of high-energy electron flux of solar storms (pretty broad definition), you better have ways to use, store or convert all ...


4

What you are describing is basically a permutation of the basic concept of a magnetic sail. You need a much bigger sail to get useful thrust, but it can just be a loop of superconductor carrying a current. To see that the sail needs to be bigger, let's pick a number out of the air and suppose that your magnets could somehow "push away" 1 million ...


4

No. The interstellar medium is almost a vacuum, just like the heliosphere. In fact, this is a lower pressure than we've ever created on Earth, at 1-1000 atoms/cm3, so 1020 times lower than atmosperic pressure on Earth.


4

Some issues with this: Drag is dependent on cross-sectional area, and so is solar radiation pressure. This would mean that different spacecraft would have a different definition of space. We might get around this by designing a "standard spacecraft", but that's exactly what defining the Karman line was for in the first place. The exosphere is complicated ...


4

That is fairly obvious from the factoid you state yourself. In regions, of a celestial body, that are not shielded by an atmosphere and that are never lit by the sun, the temperatature can go down very, very low - actually close to the temperature of the Cosmic Background Radiation (2.725 K). So in permanently shadowed lunar craters the Helium-3 simply has ...


3

Since you already have a comet available near Mars, I would propose landing it it on Mars instead. Soft-landing it is only an optional feature and not a hard requirement. You will get all the volatiles (and non-volatiles as well) on Mars. Quite possible that you'll create a hydrosphere at the same time. You will make quite a strong dust storm, but Mars is ...


3

This is an interesting question to ask but unfortunately is one with: a) a complex answer requiring much study to explore the variables and b) many different regimes according to altitude and the various perturbations that apply A million years is a long time, perhaps a lot comes down to how much of an orbit disturbance is significant to you over that ...


3

Solar flares travel at about 2000 km/s. Radio travels at 300,000 km/s, so a spacecraft at L1 (1.5 million km out) like DISCOVR gives about 12 minutes of warning when the solar flare reaches it. Spacecraft like SOHO observe the sun, and these observations are used by e.g. NOAA to try and predict flares: Current methods of flare prediction are ...


3

You may be asking about a couple of different things here. 1 Events at the surface of the sun Events at the Sun itself may or may not head in the direction of the Earth, but this is step one of a prediction system. I believe there are two approaches: a) look at what happened about a month ago and predict that it will be still there when that part of ...


3

Interesting idea. It seems unlikely to me though. So without doing any research: if the bow wave was a barrier to radio, we wouldn't be able to to radio astronomy. the bow wave has a much lower density than our atmosphere, so plasma effects are going to be much weaker. More later.


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