Kerbooster Light: Stock Satellite Launcher

[Torquemadus]

I'm playing a 0.90 stock save on hardcore custom difficulty.

As you can imagine, things can get a bit grindy if I don't do a good job of planning missions and minimising launch costs. In previous patches, I used my Kerbooster fly-back booster family to keep launch costs under control. As my 0.90 save begins to make progress, I'm ready to start introducing Kerboosters in 0.90.

My crewed missions to Kerbin's moons are still using the expendable Zedstone booster, which can be used to throw crewed spacecraft to Kerbin's moons at a good price. Once there, they can perform landings and/or spam orbital survey contracts, earning back vastly greater amounts than they cost to launch.

Earning money from satellites is more difficult, since they usually complete only one contract before returning to Kerbin for recovery. There are some other contracts they could perform, but I have crewed survey ships stationed at Kerbin's moons that can deal with those. The satellites need a cheap launch vehicle to keep their contracts economical.

The Kerbooster is a low cost two stage to orbit (TSTO) launch vehicle. It consists of an expendable solid rocket stage, and a liquid fuelled fly-back stage. I've built much larger versions in previous patches, but this version is designed to work within the limits of my current hardcore difficulty save and the limited building upgrades I've been able to afford.

Pictured below is the Kerbooster in it's lightest configuration. The staging strategy is similar to the Zedstone, but performance is sacrificed in favour of re-useability. It uses four SRBs as a first stage and uses a similar second stage to the Zedstone.

The solids provide all of the first stage thrust. I pause briefly before igniting the second stage to give the solids time to get clear after separating.

An important feature of the Kerbooster Light is that the satellite is still counted as having undergone an uncrewed launch.

While I'm at it, I recover the cost of the launch clamps, which are still present on the launch pad as debris. There's a myth going around in KSP that funds can only be recovered from debris if it has a probe core attached. Actually, it can be recovered, but you don't see the dialogue telling you how much money you got back. If in doubt, check how much funds you had before and after recovering.

Depending on the size of the payload, my Kerboosters often have spare fuel when they reach orbit, so I often use part of their remaining fuel to perform some, or all, of the departure burn. In this case, I stopped the burn part way because I wanted to preserve a good reserve of fuel for recovery. I don't actually need all that much fuel to get back to Kerbin, but my re-entries are often off target, so I like to keep a reserve of fuel in case I need to compensate.

I usually do a few aerobraking passes first. These make it easier to perform an accurate re-entry, so that I can hopefully bring my fly-back booster down within gliding distance of the KSC.

It's always difficult to get an accurate re-entry without mods. I usually count myself to have been successful if I emerge from re-entry heating somewhere over the KSC. After all, I can easily circle around to loose height.

Next, I need to turn around and line up with the runway.

I used to position the rear wheels under the wings, but since 0.90, I've had to move the wheels to the fuselage for stability. It sucks to make it all the way back to the runway, only to end up flipped upside down.

I could get better performance if I used a probe core instead of a pilot. However, the fly-back stage is designed to glide long distances if my re-entry is inaccurate (which it often is). If I do a long glide after a night re-entry, I often run out of electricity for my reaction wheels. My fly-back stage can still land without reaction wheels, but only because the pilot doesn't run on electricity!

[MoreUmpf]

Your starting Funds are set to 0. How are you able to build even anything?

Other than that it's a nice little spaceplane to start out with

Edited January 11, 2015 by MoreUmpf

[SpaceCars]

Your starting Funds are set to 0. How are you able to build even anything?

With the advance from the first contracts that he accepts, I bet.

[MoreUmpf]

With the advance from the first contracts that he accepts, I bet.

Ah right, I missed that.