How big (in meters) are Class E asteroids?

[Xyphos]

I got an idea for a new asteroid wrangler and I want to test it out, but I don't know how big I should make it.

 

 

Edited May 29, 2016 by Xyphos

[The_Rocketeer]

@XyphosYou might want to add a label to the 'asteroid' in your image - it took me a minute to realise I was looking at it.

Edited May 28, 2016 by The_Rocketeer

[mjn33]

From the description in-game: "Class E Objects are proper behemoths. No less than 18m in radius, they don't just look heavy, they are in fact far more massive than it would seem." I assume that description is accurate.

[nli2work]

here's a E-Class with bunch of parts for scale. looks a bit larger than 18m, more like ~30m diameter... there's probably a large variation in sizes

https://imgur.com/a/VOE40

Edited May 28, 2016 by nli2work

[Omegagoldfish]

The minimum size is 18 meters. They could be much larger.

[Xyphos]

3 hours ago, The_Rocketeer said:

@XyphosYou might want to add a label to the 'asteroid' in your image - it took me a minute to realise I was looking at it.

done. no matter what, we always seem to miss an important detail.

2 hours ago, nli2work said:

here's a E-Class with bunch of parts for scale. looks a bit larger than 18m, more like ~30m diameter... there's probably a large variation in sizes

https://imgur.com/a/VOE40

impressive gallery, how'd you get those captions at the bottom of your screenshots?

also, the very first picture shows two Mk3 fuel fusealges almost spanning the asteroid, so three or four ought to do it, with a cone near the center for smaller 'roids. got it. thanks!

[KerbalOmmex]

But beware! E-Class asteroids can be as heavy as 4000 tonnes and be a 100 m in diameter.

[Findthepin1]

If it's 30 or so meters across, then the radius is around 15 meters. See, it says "No less than 18 meters in radius..."

So one 30 meters across is actually a really small E-class if the math checks out. Actually, that would make it smaller than the 18 meters minimum the game itself describes. Cool, an anomaly. 

Edited May 29, 2016 by Findthepin1

[Superfluous J]

I suggest you bring a ship up there just to capture the thing into an elliptical Kerbin orbit, and have some way on that capturing ship (or send up another one with such capability) to measure it. Like, say, a little detachable ship that can target a docking port on the other ship, so you can target it, go to the other side, and see how far it is.

Then, build your transport ship.

By the way that's a great idea, one I've done in the past with smaller asteroids and it works pretty well. Make sure you've got struts connecting the arms together though

[THX1138]

On 28/05/2016 at 10:52 PM, Xyphos said:

I got an idea for a new asteroid wrangler and I want to test it out, but I don't know how big I should make it.

 

 

Did this work out for you? What is the advantage to having the girders wrap around the asteroid as opposed to pointing straight out?

[Rocket In My Pocket]

I admittedly don't have a lot of experience with moving asteroids but I've always heard that pulling is better than pushing.

Perhaps someone who's done this on a regular basis can weigh in on the pros and cons of pushing vs. pulling designs.

Or perhaps I'm misunderstanding your diagram and it is a puller.

[GwynJHawke]

I don't think you'd have to wrap around the asteroid.  Straight out to the sides might work well.

With a pusher, you have to be lined up with center of mass exactly.  With pulling, you can free pivot your claw and let inertia pull the mass of the asteroid perfectly behind you.

[Just Jim]

The biggest class-E I've seen, by far, is my Emiko asteroid.  It first weighed in at well over 3,700 ton and best guess is roughly 100 meters in diameter.

[wibou7]

I am planning the same kind of misson to capture an asteroid that will come as close as 200km (!!!) from Kerbin.

I have a puller design with arms 30 meters across that worked quite well on D class asteroid but I fear it won't be enough for a class E.

Is there a mod to remotely get information from asteroid?

In any case, keep us informed with your progress. And share your designs

[LordFerret]

1 hour ago, GwynJHawke said:

With a pusher, you have to be lined up with center of mass exactly.

That's not very hard to do, especially considering all you need do is right-click the asteroid and have it display its center of mass - X marks the spot - aim for it... and the Claw can adjust for it. I've never had a problem pushing asteroids in or out of orbit. At worst, it just takes a little patience and planning in course adjustments.

[LaytheDragon]

Oh, I had a space-station with a massive claw like that wrapping around a Class C asteroid in my 0.90 career, except with 1.25 meter fuel tanks curving around it instead of girders. I remember sending a second one up to rendezvous in LKO, when the first one's massive fuel tank claw was too small to wrap around the asteroid, to allow the actual claw part to reach (more relevant, but not pics). Also, in 1.0.4, I made an dres-teroid mining space station with a larger "claw" that looked as if it was attached as the smaller claw was, but that ship was to mine dres-teroids and serve as a capable mobile space station, not as an asteroid tug (if you request, pics will be provided).

What class of asteroid are you trying to wrangle?

And you can always modify the design to be able to push or pull (create two variants) by mounting the nukes on different positions. I see an easy way to mount the engines to pull (just mount them facing the opposite direction as in the diagram, by attaching a fuel tank radially to the side of the top of the girders (around the same area you intended the engines to be), and sticking the nukes on in a puller position).

Edited July 3, 2016 by LaytheDragon

[wibou7]

Soooo...  I did it today, I captured my first class E asteroid. And gosh are those MASSIVE. Long story short, the biggest PULLER design I could come up with has arms 50 meters across and it barely fitted into the VAB...

Even then it was completely dwarfed by this class E sheer monstrosity:
(capture craft shown is a PUSHER as no puller would ever be able to fit on that beast)

This monster is at least 70 meters in diameters and weight 4513t !  For comparison, the puller is about 10m in length.
Prior to capture I had a utterly massive 9315m/s delta-v (0.21 TWR) and it shrinked to 134m/s (0.01 TWR) when I grabbed that thing (!!!!).

That 134m/s is for about 45 minutes of burn time and I need ~900m/s to get into an equatorial orbit.
That's ~5 hours of burn plus the time required to drill and refine the ore. Needless to say I am very tempted to cheat my way out of this...

 

[Astrofox]

@wibou7 Just make some burns on your way to periapsis.

Of course, you want to have burns that you can do that will lower your velocity, and make your periapsis closer to Kerbin (just above 70km). A helpful tip for completing maneuver nodes precisely is to divide the time estimated in two, and then start burning at that time.

Plus, when you start making converting the ore into fuel the mass of the asteroid decreases, and when you burn off that fuel your TWR will most likely be higher than when you started.

So, I propose the idea that you should set up a maneuver, complete it, set up another while you are refueling, and repeat until you reach your desired orbit.

It may not be the most efficient, but it will probably be more tolerable.

[wibou7]

33 minutes ago, Astrofox said:

@wibou7 Just make some burns on your way to periapsis.

Of course, you want to have burns that you can do that will lower your velocity, and make your periapsis closer to Kerbin (just above 70km). A helpful tip for completing maneuver nodes precisely is to divide the time estimated in two, and then start burning at that time.

Plus, when you start making converting the ore into fuel the mass of the asteroid decreases, and when you burn off that fuel your TWR will most likely be higher than when you started.

So, I propose the idea that you should set up a maneuver, complete it, set up another while you are refueling, and repeat until you reach your desired orbit.

It may not be the most efficient, but it will probably be more tolerable.

I think you didn't catch my point... The asteroid is in orbit, I'm talking about plane change to get it into an equatorial orbit.

Unless I get much MUCH more trust, I'd still need about FIVE HOURS of burns in total to push it by 900m/s.

Indeed, converting ore into fuel will remove some mass from the asteroid... but considering that this beast weight 4513 tons it won't make any difference . I could turn ore into fuel for weeks and still it wouldn't make much of a dent in that mass.

[Astrofox]

@wibou7 true. Although you can lower your velocity at apoapsis, then increase your velocity at periapsis to that your apoapsis is farther out, and then you do the inclination change.

It wouldn't take very long to do readjustments at that point. The burns at Pe and Ap would be fairly long, but it may just be worth the wait.

[Corona688]

On 5/28/2016 at 4:43 PM, nli2work said:

here's a E-Class with bunch of parts for scale. looks a bit larger than 18m, more like ~30m diameter... there's probably a large variation in sizes

https://imgur.com/a/VOE40

"station pusher", missed opportunity for "shover robot"

[Xyphos]

On 7/2/2016 at 7:00 AM, Rocket In My Pocket said:

perhaps I'm misunderstanding your diagram and it is a puller.

technically, it's a new third type; a pushing puller. perhaps it can be called a hybrid? (needs a new name, I know.)
the diagram is a bit inaccurate; the engines should be near the asteroid's equator, close to the center of mass.
the engines are in fact pushing the asteroid, but the position of the grapple makes it a pulling effect and since it's near the center of mass, it should generate less rotational torque.

Edited July 4, 2016 by Xyphos