SRV Ron

There are a number of threads already on this subject. Causes range from imbalance, to aerodynamics at certain speeds, to broken struts causing twisting of add on boosters.

They behave more as a stabilizing factor while providing some lift when flying nearly parallel to the horizon for the high speed run to orbital insertion. (Dark because of the altitude and sun angle.) The turbojet section is recoverable.

While not much in lift, the fins on this turbojet design allowed me to accelerate the payload section to nearly 2,400 m/sec at over 38,000 meters at flameout. A small burn at apogee achieved orbit. The payload went to Mun orbit and return.

Simple asparagus design with skippers but a pair of Mainsail on the last set places a full orange fuel can in orbit with fuel to spare. The core stage is recoverable.

Something as simple as a broken strut can cause this; When the problem was located, this design flew with no spin or other control issues;

Test poodle and hydraulic manifold on an escape trajectory out of Kerbal. Used an all SRB rocket for the test.

SSTO with rockets is most useful for small probes to orbit although it is possible to reach Mun or Minmus with one. While a large single stage can also reach low orbit, it is more efficient if you two stage them with the payload. Turbojet engines can also be used although you don't have to use them as a aircraft. Examples below. This will do Mun orbit and return if flown carefully. At staging, you should be doing close to 2,400 m/sec at 38,000 meters, the flameout point of the turbojet. Flameout; The turbojet booster is recoverable. All rocket SSTO for a satellite; More practicable

Some payloads, the cupola as an example, are aerodynamically unstable during launch. They can cause your rocket to swap ends at certain stages of flight. Others can cause a swap if you execute an orbital turn too quickly. Example, the rocket on the left flies stable to orbit. The one on the right will swap ends early in second stage flight without the stabilizing fins.

Can make for a really bad day if your engine is taken out by an exploding spent stage. A set of sepatrons to push the spent stage out of the way can easily fix the issue of slow separation.

While the mods and aids will help you greatly in designing rockets to fulfill those missions, you are missing out on the fun and learning experience of doing it the Kerbal way. Go to the Kerbal School of Hard Knocks. Just build something and see how it works. If it doesn't work, try something else. When it does work, tweak the design to see if it will work better. Build simple. Simple smaller designs are easier to upgrade to fly better then big complex expensive ones. Example of an early career design, the first basic rocket; As is, it will reach 5,000 meters with lots of aerodynamic heating and blow up with the pod surviving upon landing. But, it will also, with proper tweaking and flying, reach well over 33,000 meters and land intact in the ocean just offshore of the launch facility for nearly 100% recovery.

Given that the possibly of paying for the research into the production of unlocked parts before they can be used, I can see the possibility of the reputation being used for the application and amount of the government grants to be used to pay for said production. The higher the reputation, the easier it will be to get those building funds.

Orange tank not needed for the LV-N. This 10 piece challenge one way design even made Voyager escape. Replace the capsule with a Stayputnik and SAS.

I have found that if a probe ends up with the fixed panels edge on, you will eventually lose all power. Just remember to reorientate the ship so at least one solar panels get fully exposed.

Start with simple rockets. If in Career Mode, unlock the Stayputnik, Oxstat solar panel and a Too Hot thermometer. Then build a low cost one way probe to land on Mun and Minmus. Then head for interplanetary for Duna and Eve. Later play with probes that can return to Kerbal before conducting manned missions. Example designs for landers. Career moon lander Enough fuel is left for return if I had a parachute on board. Career Duna, or Eve lander You can, of course, play with designs in Sandbox before accepting the challenge of the exploration contracts in career.

A note on those Explore Ike, Mun, Minmus, Duna, Eve contracts. You don't need to send a Kerbal and return him to complete those contract. Just send a probe with a Too Hot Thermometer on a one way mission along with a second one to remain in orbit for future data contracts. Send your Kerbal later to gather samples, plant a flag, and return science.

Try this test with three rockets of the exact same size. 1. Do a straight up burn at dusk until you reach Duna orbit. Note the fuel left. 2. Burn to orbit, then do an escape burn prograde to Kerban to a Duna orbit intercept. 3. Burn to orbit, then burn to Kerban escape, then burn to a Duna orbit intercept. The results; 1. Extremely inefficient. 2. Most efficient of all since little extra fuel is needed once escape has been reached using the Oberth effect to intercept the Duna orbit. However, you need to know that the intercept window is available at launch in order to get a Duna intercept. 3. Not as efficient due to more fuel is needed to intercept once you have escaped Kerbal to a solar orbit. However, it is the most common method used in the sim for interplanetary missions.

And, this bug causes extreme sideways drift with a very slow decent under drogue parachutes.

A bare bone one way Duna or Eve rocket for probe landing. You will need to use aerobraking to capture for landing. From a challenge of the 10 part two stage design; It even made Jool and Laythe Plan on that design being a one way mission as well.

In addition to coming in at as shallow an angle as possible, try to land in a valley where the atmosphere is a bit thicker. You will still need to use engines to reduce descent speed to a safe level at the last 100 meters

The hydraulic ones have usually had higher force then the other two. You pay for that in higher mass. On all side decouplers, to prevent the rotational forces, you need to have your boosters centered on them. The same goes for braces including any fuel lines which also act as braces, match them in pairs. Braces, however, may cause any decoupler to have no decoupling force at all. In such cases, separatrons may be needed to avoid explosions caused by firing the rocket after separation.a

For a turbojet rocket launching a payload into orbit, a ring of eight intakes and a careful flight profile can get you an orbital speed near 2,400 m/sec at a ceiling of over 36,000 meters.

Don't know of any plug ins. But, the Kerbal School of Hard Knocks with quick save will find that magic slingshot to aim you into an aerocapture of Kerbal saving tons of fuel.

Sandbox or Career, build simple. You can tweak the simple low cost SRB to 50% power to get better performance. Use just SRBs for the first suborbital flights. Don't try to do too much at once. Learn what each stage of flight does. The contracts and money will come in as you gain experience. Run a Sandbox game to experiment with designs, then switch to your Career game to put them into practice.

Turbojet launcher nearing ejection burnout.

While it can be a plane SSTO with Rapier, it is not necessary. Careful balancing and watching the flight profile can get you to nearly 2,400 m/sec and over 36,000 meters before burnout. A small burn with rockets and you are in orbit. The design below will place Jeb into a low Mun orbit and return. The ejection burnout. Note altitude and speed. Landing the turbo stage, however, is a pain due to a bug involving the fins and air scoops. Note the drift under drogues and long time under descent. Once the main chute opens, landing is normal.