Occupied Command Seat Drag

[Tarmenius]

So, I've been playing around with placing Command Seats on my spaceplanes for space tourism and crew replenishment. To fill the role, I chose an SSTO designed to reach a 100 x 100 km orbit with a comfortable fuel margin. Surprisingly, the Command Seats themselves didn't have as much of an effect on flight characteristics as I expected them to and the craft needed no major modifications to accommodate them.

So, I loaded up some passengers for the first flight to my station and could barely reach orbit at all. I had to use RCS thrust to bridge the last 60 m/s or so just for a 100 x 71 km orbit. This leads me to wonder: just how much drag do the Kerbals add to the craft? It must be something rather significant, as simply adding the drag from six normal parts would not result in such a drastic decline in performance.

Does anyone have the exact numbers, or at least a close approximation?

[Deadweasel]

Don't know that it's actual drag, so much as weight. The kerbals bring additional pounds when they're on-board now. Especially Bob, that fat doughnut-hogging schemer.

[Tarmenius]

Well, I suppose it's time to slap a few Command Seats on a rocket and see how much dv I lose when the crew move from the Pod to the Seat. Or maybe the crafts mass will change in the Knowledge Base and make my life a little easier

[Edit] Sure enough, the mass did change in the Knowledge Base. According to my calculations, each Kerbal has a mass of around 0.09 tons when placed in a Command Seat. However, the six I placed on my SSTO only add 0.54 tons, which doesn't sound like it should make as much of an impact as it did. I guess I'll have to do some more playing around to find out for sure.

Edited June 10, 2013 by Tarmenius

[Deadweasel]

Well, I suppose it's time to slap a few Command Seats on a rocket and see how much dv I lose when the crew move from the Pod to the Seat. Or maybe the crafts mass will change in the Knowledge Base and make my life a little easier

Okay, I lied (I think). I thought the Kerbals imparted mass regardless of their position on/in a craft, but it seems I was wrong.

Banshee III and crew

Ship information (including total mass)

And again, after unloading the crew

Hmmmm....

Elner: "What's with the tears?"

Mac: "He called me FAAAAAAT!"

Elner: "Well, apparently we don't weigh anything, so knock it off already."

Mac: "But I don't WANNA weigh nothing! WAAAAAHHH!!"

[Tarmenius]

Yeah, it seems that the only time they impart mass is specifically when they're in a Command Seat. And now that I've given it more thought, 0.09 tons is slightly more than an Avionics Package, and having six extra of those would certainly be noticeable. Looks like I have to reduce the passenger list a bit. Or use a more powerful SSTO...

Either way, thanks for the input. It's appreciated. And by the way, which mod are those slick-looking parts from?

[bsalis]

So they weigh 90Kg when seated... Even though they are only 1m tall!

But weigh nothing in a pod or cockpit?

Methinks for gaming simplicity they should weigh nothing.

[Brotoro]

90 kg is pretty heavy for a kerbal. What are they carrying in thise backpacks anyway?

Oooohh, yes... The snacks.

[The Destroyer]

Either way, thanks for the input. It's appreciated. And by the way, which mod are those slick-looking parts from?

B9 Aerospace. Get it, its SUPERAWESOME for large carriers and airplanes. Or massive awesome looking rockets.

[DisarmingBaton5]

Take all the snacks out and make them SKINNY!

[Deadweasel]

B9 Aerospace. Get it, its SUPERAWESOME for large carriers and airplanes. Or massive awesome looking rockets.

Heh, yeah as stated it's the B9 Aerospace pack.

http://kerbalspaceprogram.com/0-19-1-b9-aerospace-pack-release-2/

[Tarmenius]

Heh, yeah as stated it's the B9 Aerospace pack.

Thanks, that will have to be the next mod I try.

Methinks for gaming simplicity they should weigh nothing.

Agreed. When I first noticed the drop in performance, I considered mass as the culprit, but then I thought "No, they don't add mass to Command Pods, why would they add mass to Command Seats?" Which is why I figured it must be a drag issue. I have since added that info to the Command Seat part description so I'll remember to account for it.

Kerbals should either always add their mass to whatever part they occupy, or never add their mass. Both ways can make sense, its just a matter of consistency.

Edited June 11, 2013 by Tarmenius

[Henri von Braun]

I agree with Brotoro and bsalis. 0.09 tons or 90 kg is pretty heavy. Fat Kerbals, we never ever see them eating. How unfair.

By the way, how do you think they would eat like? Would it go *barf barf gobble gobble* or * nibble nibble* ? I don't know, and this could be added in the game ( just for giggles, you know ).

[Deadweasel]

I agree with Brotoro and bsalis. 0.09 tons or 90 kg is pretty heavy. Fat Kerbals, we never ever see them eating. How unfair.

By the way, how do you think they would eat like? Would it go *barf barf gobble gobble* or * nibble nibble* ? I don't know, and this could be added in the game ( just for giggles, you know ).

Look at the size of those mouths! Pretty sure watching a kerbal eat would call to mind imagery of tossing out an entire meal at one time into a trash can.

[sgt_flyer]

bah, everything has a higher density on kerbin (even Kerbals )

[rryy]

Most of their mass would probably come from the RCS and the EVA pack, as well as the "life support", helmet, and of course the snacks. I would guess that without all of those "necessary" equipment, a Kerbal would only have a mass of about 30 kg.

Using that to solve your problem, just have them go up without any life support!

[Sapphire]

Can we send Kerbals to space wearing only underpants? Preferably white boxers covered in hearts.

[Tarmenius]

Look at the size of those mouths! Pretty sure watching a kerbal eat would call to mind imagery of tossing out an entire meal at one time into a trash can.

Or Garfield and a lasagna...

After giving it some thought, I like the idea of even the Command Pods increasing in total mass depending on how many Kerbals are inside. Astronaut weight is a necessary consideration when planning a real-life mission, so why shouldn't we as well? As long as the game mechanics make it simple to visualize, there shouldn't be a problem.

On a side note, how do I change the title of the thread to "Kerbal Mass in Command Seats"? Or is that something a mod would need to do?

Edited June 11, 2013 by Tarmenius