Anyone put asteroids in orbit around moonless planets?

[Galane]

Has anyone done that yet? Moho is awful lonely without a moon.

[TimberWolffe]

I wish asteroids had gravity. Put an asteroid in an orbit around an asteroid in an orbit around an asteroid in an orbit around the Mun. Hell, you could probably work it out to have a figure of 8 orbit around 2 other asteroids

[Silver_Swift]

Why don't asteroids have gravity? Would it be that CPU intensive to have an object that is both influenced by the gravity of other objects and in turn exerts its own gravity on other objects?

If that is the case would it be easier to do with the abstraction that smaller classes of objects don't effect larger classes of objects (ie. planets effects ships and asteroids, asteroids effect only ships and smaller asteroids, ships don't effect anything).

[Guest]

The asteroids are too small and light to have any noticeable gravity.

[TimberWolffe]

The asteroids are too small and light to have any noticeable gravity.

Depends on the size, really. Some asteroids IIRC are the size of Minmus

[Rune]

Why don't asteroids have gravity? Would it be that CPU intensive to have an object that is both influenced by the gravity of other objects and in turn exerts its own gravity on other objects?

If that is the case would it be easier to do with the abstraction that smaller classes of objects don't effect larger classes of objects (ie. planets effects ships and asteroids, asteroids effect only ships and smaller asteroids, ships don't effect anything).

Oh my Kod. You are walking around the edges of the n-body physics discussion! Quick, abandon thread while you can!

Now seriously, that's much more complicated than it sounds. The real n-body problem is not solvable in an exact form in RL, and the approximations are a pain in the ass and, while doable, KSP's dev team has more or lees promised they will never make it into the game. Discussed to death a bunch of times, so hardly worth bringing that up. The categories system wont work with the "single SOI, single gravity well" system, too, though that I hadn't heard before. So sorry, it's not a bad idea (plenty of people though so at least), but we won't get it.

Rune. It would complicate navigation a couple orders of magnitude, too, people forget that, no stable orbits anymore.

[KerbMav]

Hm, if every asteroid had a very small SOI ... how would "docking" with the claw work or flybys of the asteroid? I think they would work and have very little influence on the ships path - but what happens (in KSP code) if a parent body enters the SOI of its satellite?

[ratchet freak]

idea for a challenge; the mentoring program: give each body in the system a new moon

[Renegrade]

Well, some asteroid factlets are warranted here.

I've seen G-class asteroids over 1,500 tons (1e+6kg), possibly larger. They're supposedly about 30m in diameter, although I haven't measured.

Mass: 1.5e+6 kg

Radius: 15m

Density: 106.103 kg/m^3 (it would float on water. Earth is ~5500kg/m^3, water is ~1000kg/m^3, Kerbin is 58,484 kg/m^3)

Surface Gravity: 444.923 nm/s^2 (A kerbal in an EVA suit would weigh about 4.1 milligrams here)

Surface escape velocity: 3.653 mm/sec

An orbit around it at an altitude of 5m above the surface would take 936 minutes and spend about 27% of that time in it's shadow at a speed of 2.237mm/sec.

[TimberWolffe]

Well, some asteroid factlets are warranted here.

I've seen G-class asteroids over 1,500 tons (1e+6kg), possibly larger. They're supposedly about 30m in diameter, although I haven't measured.

Mass: 1.5e+6 kg

Radius: 15m

Density: 106.103 kg/m^3 (it would float on water. Earth is ~5500kg/m^3, water is ~1000kg/m^3, Kerbin is 58,484 kg/m^3)

Surface Gravity: 444.923 nm/s^2 (A kerbal in an EVA suit would weigh about 4.1 milligrams here)

Surface escape velocity: 3.653 mm/sec

An orbit around it at an altitude of 5m above the surface would take 936 minutes and spend about 27% of that time in it's shadow at a speed of 2.237mm/sec.

but it's possible tho

[Mesons]

Why don't asteroids have gravity? Would it be that CPU intensive to have an object that is both influenced by the gravity of other objects and in turn exerts its own gravity on other objects?

Yes, yes it would. Why do you think KSP uses SOIs and patched conics instead of n-body physics in the first place? The biggest issue is precision errors from the need to use a finite time step (nature does not have an upper limit on processing speed).

Oh my Kod. You are walking around the edges of the n-body physics discussion! Quick, abandon thread while you can!

Now seriously, that's much more complicated than it sounds. The real n-body problem is not solvable in an exact form in RL, and the approximations are a pain in the ass and, while doable, KSP's dev team has more or lees promised they will never make it into the game. Discussed to death a bunch of times, so hardly worth bringing that up. The categories system wont work with the "single SOI, single gravity well" system, too, though that I hadn't heard before. So sorry, it's not a bad idea (plenty of people though so at least), but we won't get it.

Unfortunately, as cool as it could be (trust me, I would like it too), I think we can all be certain KSP will never have n-body gravity.

[Galane]

idea for a challenge; the mentoring program: give each body in the system a new moon

OK, post that in the challenges forum.

[cantab]

Does Ike count?

Yes, it's in near-polar orbit. Yes, it will glow green as soon as I get round to editing the attached lights in the savefile.

[Galane]

Asteroid demolition derby. Put an asteroid in a retrograde orbit, same altitude etc as an existing space station. Have the station the active craft and wait until the asteroid collides with it.

[ratchet freak]

OK, post that in the challenges forum.

except it's more tedious than fun, there are 17 bodies you need to put a rock around,

[Galane]

How about the "Rock Around the Clock" challenge? 12 evenly spaced asteroids in synchronous Kerbin orbit.

[cantab]

Same issue tbh. Doing the same thing several times is more an exercise in patience than a real challenge.

Now anyone who can put an asteroid in Moho orbit I will salute.

[Renegrade]

but it's possible tho

Yep, in real life, you could orbit that in a number of situations. Just have to be patient, and not have too much outside interference.

Might even be able to make a planet in KSP with those parameters and orbit it, assuming underflow doesn't rear it's ugly head.

By comparison though, orbital speed at Gilly varies from 25,250 mm/sec (25.3m/sec) to about 7,690 mm/sec (7.7m/sec) between 0m and 127km altitudes.

Same issue tbh. Doing the same thing several times is more an exercise in patience than a real challenge.

Now anyone who can put an asteroid in Moho orbit I will salute.

The little ones are only 5-15t or something like that... might even be lighter than the Mk1-2 capsule... actually looksie:

			PART
			{
				name = PotatoRoid
				uid = 1009265843
				mid = 1009265843
				launchID = 0
				parent = 0
				position = 0,0,0
				rotation = 0,0,0,1
				mirror = 1,1,1
				istg = 0
				dstg = 0
				sqor = 0
				sidx = 0
				attm = 0
				srfN = None, -1
				mass = 2.526269
				temp = 14.48548
				expt = 0.1
				state = 1
				connected = True
				attached = True
				flag = 
				rTrf = PotatoRoid (Ast. GWH-018)
				modCost = 0
				EVENTS
				{
				}
				ACTIONS
				{
				}
				MODULE
				{
					name = ModuleAsteroid
					isEnabled = True
					seed = 18340724
					AsteroidName = Ast. GWH-018
					prefabBaseURL = Procedural/PA_A
					EVENTS
					{
						MakeTarget
						{
							active = True
							guiActive = True
							guiIcon = Target Center of Mass
							guiName = Target Center of Mass
							category = Target Center of Mass
							guiActiveUnfocused = True
							unfocusedRange = 500
							externalToEVAOnly = False
						}
						TakeSampleEVAEvent
						{
							active = True
							guiActive = False
							guiIcon = Take Sample
							guiName = Take Sample
							category = Take Sample
							guiActiveUnfocused = True
							unfocusedRange = 4.319753
							externalToEVAOnly = True
						}
						RenameAsteroidEvent
						{
							active = True
							guiActive = True
							guiIcon = Rename Asteroid
							guiName = Rename Asteroid
							category = Rename Asteroid
							guiActiveUnfocused = True
							unfocusedRange = 4.319753
							externalToEVAOnly = True
						}
					}
					ACTIONS
					{
					}
				}
			}

If I'm reading that, this potatoroid is almost as light as a 0.25 cupola!

Shouldn't be too hard to give potato-y moho it's own microscopic potato-y mun then..

[WWEdeadman]

Does Ike count?

/snip/

Yes, it's in near-polar orbit. Yes, it will glow green as soon as I get round to editing the attached lights in the savefile.

I guess you named it "Magic Boulder" ?

[CaptRobau]

Yes, yes it would. Why do you think KSP uses SOIs and patched conics instead of n-body physics in the first place? The biggest issue is precision errors from the need to use a finite time step (nature does not have an upper limit on processing speed).

The biggest reason is orbital decay and the effect it would have on your missions. Do a timewarp for a mission to Jool and five spacestations would deorbit in that time due to gravitational forces. That's not fun at all.

[NERVAfan]

Well, some asteroid factlets are warranted here.

I've seen G-class asteroids over 1,500 tons (1e+6kg), possibly larger. They're supposedly about 30m in diameter, although I haven't measured.

Isn't E class the biggest?

Density: 106.103 kg/m^3 (it would float on water. Earth is ~5500kg/m^3, water is ~1000kg/m^3, Kerbin is 58,484 kg/m^3)

Wow, that's light. I thought E classes were supposed to be dense?

Surface escape velocity: 3.653 mm/sec

LOL. Sneeze to escape velocity.

[Renegrade]

Isn't E class the biggest?

Uhh, right! E-class. The biggest ones. Been writing too many scripts for problems like the above, and G / g0 comes up quite a bit, so it's now my default letter hehe.

Wow, that's light. I thought E classes were supposed to be dense?

When I saw the density, I was reminded of a certain scene in the Holy Grail... "what else floats on water?" "really big asteroids!!"

They're very massive, but not particularly dense. They're supposedly 30m in diameter (15m radius; I have not measured this directly in game though), which makes them very big for 1500 tons.

LOL. Sneeze to escape velocity.

Yep! An eighth of an inch per second in Customary Units, or just under a meter every five minutes. Given that a typical walking speed is about 1388mm/sec (5km/h), you'd have to move very, very slowly to avoid hitting escape velocity...

Update: the in game description of an E-class asteroid is actually "no less than 18m in radius" so we're talking about a density of only 0.061 kg/m^3, unless someone's seen a rock heavier than 1500t.

Edited October 3, 2014 by Renegrade

[SkyRender]

I really should give Dres a little brother to keep it company at some point. And give Eeloo some space rock company too.

[Galane]

Do you have to leave something attached to an asteroid to prevent the game from deleting it?

[cantab]

Around 3000 tons is the usual limit for E-classes. There are rumours of bigger ones but they're super-rare.