Space Experts!

Apr 12, 2021
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Hello!

Just to quickly ask, I am looking for those with expert/professional knowledge about astronomy, and anything space-incorporated in general. This is to act as a guide/reference/expert source to aid in a Sci-Fi book I am currently writing; whilst I like to think I have good basic knowledge, enough to tackle a Sci-Fi genre, I naturally want to ensure I don't wrongly interpret any facts or information I have found myself, and that the inner/more specific details I am hoping to cover, are accurately done so! I know all too well, the scolding many can get when they get it wrong!

Of course, there are fantasy/cosmic horror elements involved, so certain criteria aren't needed to be an absolutely accurate representation, but the closest I can get to what it would be, and utilising what we realistically expect in the future to be a possibility are of a high priority!

So, if you fall into this category, have expert/professional knowledge, and want to be involved with the creation of a new large Sci-Fi/Cosmic Horror series, please contact me for more information!

Thank you!
 

COLGeek

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Apr 3, 2020
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You should post questions in the appropriate section of the forum (as close as possible, anyway) to solicit input. Just be clear on your intent.

We have some folks who frequent the site that can get VERY technical. Just something to be aware of.

Good luck.
 
Apr 12, 2021
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Thank you! Indeed; I believe I'll be here fairly often; lots of big questions I imagine having! Just thinking of a less cumbersome way to manage this particular situation, and have it in more of a chat format!
 
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Thank you! Indeed; I believe I'll be here fairly often; lots of big questions I imagine having! Just thinking of a less cumbersome way to manage this particular situation, and have it in more of a chat format!
Your questions will likely generate more interest and response than you might expect. We enjoy answering questions because it "sharpens our steel".

The recent article about a new movie involving a ship traveling 86 light years -- of the 4700 known, none are there -- to another planet almost was enough for me to post a list of things too often that are portrayed wrong in movies, especially very cool relativistic effects. But I decided that my efforts would just be a waste of time. I tried to get the Sunshine folks to get the Sun's color right, but to no avail even though they had a physicist help them. :(
 

Catastrophe

Approaching asteroid? Is this THE one?
Feb 18, 2020
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No. I actually meant that the asteroid belt is shown as closely packed lumps of stone that have to be dodged.

I think there was a Stargate, when they had to shoot their way through the edge of the belt because their shields were down. Actually asterods are widely spaced. I think possibly microasteroids (aka dust ;) ) might be more plentiful. Probably difficult to check from here.

Cat :)
 
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No. I actually meant that the asteroid belt is shown as closely packed lumps of stone that have to be dodged.
Ah, yes. There is good reason why space probes sail directly through the asteroid belt. :) It's not impossible to hit one, but the odds are so much against it that it's worth not having to pay extra to fly "up and over".

Of course, seeing a small asteroid all by itself in an movie production would be pointless for them, so another faux hazard comes our way.
 

Catastrophe

Approaching asteroid? Is this THE one?
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"Asteroids range in size from Vesta—the largest at about 329 miles (530 kilometers) in diameter - to bodies that are less than 33 feet (10 meters) across."

Then you have microasteroids and space dust. Remember kinetic energy is 1/2 m v^2 .
and some of these velocities can be quite large. "Their average orbital velocities range between 17 and 25 km/s (38,029 to 55,925 mph)." That is in Asteroid Belt. (Quora).

So there may still be some hazard from smaller bodies, or at least some extra strength to be built into space vehicles.

Cat :)
 
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I had no luck in finding an article about the odds of passing safely through the belt, so I crunched some numbers that may give an indication what the odds of hitting something traveling through the asteroid belt might be...

Odds (probability, actually) of hitting an object (as small as 1 cm in dia.) is roughly 1 in 23,000.

This uses a radial distance of 2.88 AU (middle of belt) and an inclination angle of 25 deg. (to get height). The combined cross-sectional area of the total number of asteroids, per the power law, down to 1 cm, using bins as illustrated, divided by the cross-sectional area of the belt gives the result above.

The graph below is based on a Harvard study (I misplaced the link) but it is a simple power law equation. I extrapolated down to 1 cm in diameter as illustrated.

The equation I used is N = 1E6 / 10^(2*logD). D is the diameter in km. So 3 is the log value of 1000km giving a count of N = 1. A dia. of 1 cm, therefore, is a log value of -5, giving 1E16 tiny meteoroids.

 
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Catastrophe

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pdf (iop.org)

Statistical Asteroid Model (Main Belt). Don't be fooled by short URL.

THE STATISTICAL ASTEROID MODEL. I. THE MAIN-BELT POPULATION FOR DIAMETERS GREATER THAN 1 KILOMETER Edward F. Tedesco Space Science Center, University of New Hampshire, Durham, NH 03824; ed.tedesco@unh.edu and Alberto Cellino and Vincenzo Zappala´ INAF - Osservatorio Astronomico di Torino, 10025 Pino Torinese, Torino, Italy; cellino@to.astro.it, zappala@to.astro.it Received 2002 July 10; accepted 2005 January 31

We describe the creation of a model of the main asteroid belt whose purpose is to describe the main-belt asteroid size frequency distribution and simulate the number of main-belt asteroids and their fluxes at visual through midinfrared (0.3–70 m) wavelengths in any area of sky for an arbitrary date. This model is based on a population of 1:9 ; 106 asteroids obtained from the complete known asteroid sample, plus extrapolation of the size-frequency distributions of 15 asteroid dynamical families and three background populations, to a diameter limit of 1 km. The model is compared with data and other models, example applications are given, planned refinements and extensions to the model are presented, and some implications of the resulting size frequency distribution are discussed. Key words: infrared: solar system — minor planets, asteroids — solar system: general

Cat :)
 
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Thanks, I think that matches the Harvard result fairly closely, but it seems to be for 1km sizes and larger.

I have the assumption that something as small as cm could be quite destructive to any mission. The speeds through the belt will only get faster with innovations, thus impact energies will become even more problematic.

The road building industry will often choose a 3/8" rock vs. a 1/2" rock to greatly reduce windshield damage for cars traveling, say, < 60 mph. It also makes the ride a little smoother, as another major benefit and less oil is needed, saving money. But it is also weaker in structure, so a shorter life is expected. That small difference in size affects hundreds of millions of dollars over the life of roadways (seal coat roadways, not hot mix).

I would not want to be driving a car with either one of those rocks if it hit my windshield at, say, 30,000 mph! Since KE increases as the square of velocity, it's even more concerning.

It would be interesting to see how much impact small meteoroids could do at various spacecraft velocities.
 
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Catastrophe

Approaching asteroid? Is this THE one?
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Helio, glad that helped.
Re: "It would be interesting to see how much impact small meteoroids could do at various spacecraft velocities."
That is exactly my point!

Cat :)
 

Catastrophe

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Quote
Micrometeoroids pose a significant threat to space exploration. The average velocity of micrometeoroids relative to a spacecraft in orbit is 10 kilometers per second (22,500 mph). Resistance to micrometeoroid impact is a significant design challenge for spacecraft and space suit designers (See Thermal Micrometeoroid Garment). While the tiny sizes of most micrometeoroids limits the damage incurred, the high velocity impacts will constantly degrade the outer casing of spacecraft in a manner analogous to sandblasting. Long term exposure can threaten the functionality of spacecraft systems.[12]
Quote

Micrometeoroid Wiki

Cat :)
 

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