Have issue with my rocket

[Jestersage]

So far, I am not having much luck creating a Falcon 9 + Dragon v2 clone. It is currently using 2.5m parts, so nothing from Kerbodyne except the liquid booster ( it is in the same tech-node as mainsail, and is better than orange + mainsail)

Mission profile: This is the second launch of the mission; an altair clone had been launched and is sitting at a 90k orbit, waiting for this ship.

In this launch, the ship will go to LKO before rendezvous and dock with the altair clone. It will then ride on the minmus transfer stage to minmus.

The current situation is that it does not have enough in the first/second stage to have a stable orbit.

I have a few solution:

1. Keep modifying the single core, but adjust the fuel tanks/thrusters
2. Go with falcon heavy (3 cores)
3. Give up and go with a disposable first stage, so I can significantly reduce the fuel tanks and thus mass.
4. Give up on it and just use this guy. Good design except it uses the 3.75m parts. (I use the Liquid Booster because it is in the same tech-node as mainsail)

My pastebin of my own craft is here: http://pastebin.com/AcyyGPnH

The reason why I need such an overkill ship/lander combo is because I want a functional test for the RETURN trip. dV to Minmus and back is not an issue, but the speed is, especially for direct entry. And I explicitly rule out the use of any airbraking orbit (otherwise I have a bunch of Shuttle/spaceplane/SSTO that does a better job)

Edited November 19, 2016 by Jestersage

[FancyMouse]

Consider reduce payload mass? For example the heat shield - if you don't aerobrake you probably don't need that at all, at least reduce the ablator to nearly zero if you just want to hide the ugly service bay base. Also upper stage doesn't need 4 Thuds - you don't need that TWR in space. Also you don't need that much monoprop - those inside the capsule is more than enough for docking - no need for two extra cylinder tanks in the service bay.

And I don't quite suggest making a combo like this - your extra 2.5m separator and fairing are almost the mass of the resource scanner itself. I'd launch the scanner separately in a proper 1.25m stack.

[Jestersage]

5 hours ago, FancyMouse said:

Consider reduce payload mass? For example the heat shield - if you don't aerobrake you probably don't need that at all, at least reduce the ablator to nearly zero if you just want to hide the ugly service bay base. Also upper stage doesn't need 4 Thuds - you don't need that TWR in space. Also you don't need that much monoprop - those inside the capsule is more than enough for docking - no need for two extra cylinder tanks in the service bay.

And I don't quite suggest making a combo like this - your extra 2.5m separator and fairing are almost the mass of the resource scanner itself. I'd launch the scanner separately in a proper 1.25m stack.

I thought if I enter directly from Minmus, I will have 3.2 km/s by the time I hit Kerbin according to Youtube videos (remember: direct re-entry), requiring a heatshield. I always need the extra monoprop (never managed a docking without one) But there are additional stuff hidden on the inside edge of the upper cabins and fuel tanks -- I will remove those.

As to the "combo", you are talking about the cargo in the fairing, right? TBH, I wonder what would have been contained within the trunk, if in a hyptherical situation, they use Dragon V2 instead of Orion. If they are going to carry stuff in there, I will have to put some mass in there for simulation purpose.

EDIT: I took your advice. While I kept my simulated trunk, I did managed to remove some prop tanks, and replace the 4 Thud with 12x Twitch. Managed to launch it to a 78k orbit with a lot of fuel to spare. Unable to recover the first stage due to it missing from tracking (maybe I need a mod?), but otherwise it works in theory. I may try to get that mod and gone with a smaller first stage.

Edited November 20, 2016 by Jestersage