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[1.12.0 +] D.A.R.T. Range Challenge [1.0.0] [01 Nov 2021]


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DART Range

Background

What should we do if we find a dangerous asteroid on course to hit Earth? There are a number of possible deflection techniques, ranging from extreme (a nuclear blast) to benign (a heavy spacecraft uses gravity to nudge the asteroid off-course).

Somewhere in between is the kinetic impactor technique. The concept is simple: Slam one or more spacecraft into the asteroid at high speed to change its orbit and move Earth out of the crosshairs. This technique works particularly well if used far in advance, since small nudges can add up to big changes later on.

DART, NASA's Double Asteroid Redirection Test, is the first space mission to test this or any other asteroid deflection technique. DART launches between November 2021 and February 2022 and will arrive at near-Earth asteroid Didymos in September 2022. The spacecraft won't slow down, intentionally crashing into the asteroid's small moon Dimorphos. The crash should change the time it takes Dimorphos to orbit Didymos, proving the kinetic impactor technique works.

DART Range

You can now take on the challenge of achieving the DART objectives for yourself using the DART Range mod for Kerbal Space Program.

With the installation of DART Range, Didymos and Dimorphos are added to the Kerbal universe. Didymos is classified a “planet”. Like other planets and moons in KSP, you can orbit and land on Didymos, but you cannot alter its orbit. Dimorphos is classified a “part”. Like asteroids and comets in KSP, you cannot orbit or land on Dimorphos, but you can redirect its path and change its orbit. You can also grab Dimorphos using the grabber unit.

Didymos and Dimorphos are tiny targets that offer a difficult navigational challenge, but if you are able to guide a spacecraft to an impact with Dimorphos, the resulting changes are real and immediately observable. Do you have the right stuff to save Kerbalkind from a deadly asteroid impact? Take to the DART Range and find out.

Installation

Download the DART.zip file, extract the DART folder, and copy it to the GameData folder of your KSP installation. Everything needed for it to work is self-contained; there are no required dependencies. DART Range will also be avalaible to be installed via CKAN soon.

Download from GitHub

Contributors

Galileo
JadeOfMaar
OhioBob
R-T-B
Gameslinx AKA Linx
Angel-125
theRagingIrishman

License

DART Range, Parallax - All Rights Reserved
Kopernicus - GPL
SpaceObjectSpawner - GPLV3
ModularFlightIntegrator - MIT



Screenshots
DyUC8Tb.png
ByKipqB.jpg

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12 minutes ago, linuxgurugamer said:

Is this going to be in CKAN?  Either I'm too fast LOL or something is wrong, I don't see it listed in CKAN yet

Its not there yet, we just plan to have it there, we just jumped the gun a little. Any help would be greatly appreciated lol

Edited by Galileo
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I enjoyed greatly working on this.  The custom Kopernicus integrated in this plays nicely with stock Kopernicus, just for everyones information. :)

1 hour ago, linuxgurugamer said:

Is this going to be in CKAN?  Either I'm too fast LOL or something is wrong, I don't see it listed in CKAN yet

@HebaruSan Can probably help with this.

 

Note that though it is technically self-contained, ModuleManager enables a few additional features (custom experiments IIRC).

2 hours ago, leatherneck6017 said:

Wow, what a cool idea to add this to KSP. I didn't realize the game had the mechanics to make this work.

Heh, it does, but as always there are some caveats due to it being a computer simulation.

The asteroid moonlet has a tendency to drift on it's own due to floating point errors, a side effect of how the game engine works.  Not much, but it does make it a bit odd to see it's already moved slightly when you approach it.  That's really the only thing worthy of note though, it really works rather excellent!

Fun fact:  The moonlet is actually considered a "vessel" by the game!

Edited by R-T-B
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20 minutes ago, HebaruSan said:

Is it required, or can we filter it out for CKAN and depend on the standard Kopernicus? What about the custom Parallax?

@Gameslinxwill have to comment on the custom Parallax but I'd assume a conflict for starting off, as the way it looks written doesn't seem to have any kind of workarounds.  Someone maybe could test and see for us, though?

The KopernicusDART.dll overrides (via file version detection code in KSP) and replaces standard Kopernicus if it's present as KopernicusDART.dll features an extended feature set.  So no dependency or honestly even declartation needed, but it can do a "provides" if you want as it also provides standard Kopernicus features.

But yeah that dll is needed.  And yes, to anyone concerned, that KopernicusDART version has all the latest bugfixes from mainline Kopernicus.

Edited by R-T-B
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24 minutes ago, HebaruSan said:

Is it required, or can we filter it out for CKAN and depend on the standard Kopernicus? What about the custom Parallax?

An independent and custom version of Parallax is packaged with DART. It can work alongside the main Parallax without any issues, but DART doesn't depend on main Parallax being installed 

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5 minutes ago, Clonos said:

wait no don't shoot poor dimorphos

We're just DARTing it.  For veterinary work.  It goes sleepy and then we study (for SCIENCE!).

Edited by R-T-B
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5 hours ago, linuxgurugamer said:

Is this going to be in CKAN?  Either I'm too fast LOL or something is wrong, I don't see it listed in CKAN yet

5 hours ago, Galileo said:

Its not there yet, we just plan to have it there, we just jumped the gun a little. Any help would be greatly appreciated lol

3 hours ago, R-T-B said:

The KopernicusDART.dll overrides (via file version detection code in KSP) and replaces standard Kopernicus if it's present as KopernicusDART.dll features an extended feature set.

But yeah that dll is needed.  And yes, to anyone concerned, that KopernicusDART version has all the latest bugfixes from mainline Kopernicus.

3 hours ago, Gameslinx said:

An independent and custom version of Parallax is packaged with DART. It can work alongside the main Parallax without any issues, but DART doesn't depend on main Parallax being installed 

Thanks, this should be on CKAN now.

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To make the DART Range work as planned, it was necessary to implement some custom code.  Below is an explanation of these customizations so you know what to expect should you decide to take the DART Range Challenge.

Time Warp Limits

Didymos and Dimorphos are very tiny bodies, far smaller than any other planet/moon combination in the game.  This really alters one’s perception of distance and speed.  If you happen to be on a high-speed approach and using time warp, chances are you’ll fly right on past both bodies before you even see them and have a chance to slow down.

It was therefore was necessary to implement a means to drop a vessel out of time warp to prevent accidental overshoot.  This is achieved through the use of time warp limits.  A vessel traveling at high speed automatically reduces time warp as it nears its target.  But there’s more – the limits are dynamic and a function of vessel speed.  Therefore, no matter how fast the vessel is traveling, the time interval between reductions is constant.  This means you don’t have to concern yourself with reducing time warp while on approach – just sit back and watch the show unfold.

Should a vessel happen to slow to orbital velocity (which can be less than 1 m/s), the limits are moved in close to Didymos to allow high time warps from low orbit so one can get around without painfully slow wait times.

Thanks to @R-T-B for writing the time warp code.

Tidal Locking

The tiny moonlet Dimorphos is tidally locked to its parent, Didymos.  But because Dimorphos is a part and not a celestial body, implementing and maintaining this proved to be problematic.  Special code was added to force the long axis of Dimorphos to always point toward Didymos.

This tidal locking code is either on or off, and can be disabled by an impact that sufficiently alters orbit and spin.  When the tidal lock is broken, Dimorphos will freely rotate and will never again return to its tidally locked state.

The DART mod compares the difference between the rotational and orbital angular velocities to determine if tidal lock has been broken.  Whether or not an impact event will do so depends on its force, location, and angle.  An impact comparable to the real-life DART mission can break tidal lock if it hits just right.

Thanks to @Angel-125 for writing the tidal locking code.

Orbit Change Readout

So that you can immediately see the effects of an impact on the orbit of Dimorphos, a readout is provided showing the before and after orbital elements.  This readout is triggered anytime a spacecraft passes within 250 km of the target, thus near misses will also trigger the display.

As R-T-B previously explained, anytime we pass near to Dimorphos its orbit begins to drift, with or without an impact.  We believe this to be inherent to the game engine and beyond our ability to control.  The unfortunate side effect is that we’ll see a small change in orbit even when we don’t hit the target.  If Dimorphos is hit with large enough force, however, large orbital changes can be observed.

How much an orbit changes depends on how much momentum is transferred to the target, where momentum is the product of mass and velocity.  The real-life 600-kg DART spacecraft will impact Dimorphos at a speed of about 6.5 km/s, transferring momentum of 4 million kg⋅m/s.

Thanks to @R-T-B for writing the orbit change code.
 

Edited by OhioBob
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2 hours ago, HebaruSan said:

BTW you guys are crazy for releasing custom forks instead of enhancing the main plugins. Other modders are going to want those features.

Why on earth would other modders want to specifically track for an impact with an asteroid named Dimorphos?  That's the only baked in additional thing in Koperncius that isn't going into mainline at some point (and yes, there are plans that will enable mainline to replace this if need be).  The additional features are highly mission specific.

We've thought this out, I assure you.  I believe @Gameslinx has plans for Parallax mainline as well.

I do plan to port the timewarp-limiting-on-approach code, which is rather cool, to Kopernicus mainline soonish.

Edited by R-T-B
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Guest The Doodling Astronaut

:joy: I literally downloaded GPP by team Galileo a few days ago and now I have to uninstall it to download another pack by team Galileo

 

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15 minutes ago, Neebel said:

I'd love to try this out, but it would probably only work with the stock solar system, right? Because my main install is Beyond Home right now

There's a chance it will work because DART is meant to function independent of anything else installed . I'm interested to see if it does work

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5 hours ago, Gameslinx said:

There's a chance it will work because DART is meant to function independent of anything else installed . I'm interested to see if it does work

Well I guess I'll test it today then. But the rules only allow for stock solar system anyway, so I might just make another instance with CKAN

Edited by Neebel
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