Horizon 5 blasts off! This should be a eventful mission… the first EVA (extra-vehicular-activity)… actually stepping out of the Horizon pod into space! After reaching a very stable 100k orbit (and ensuring the engine throttle is in the LOCKED position), Jebediah steps out!
“Wow! Kerbin looks so… small!” What a historic mission! Time to come home though… Jebediah sets down in the ocean west of KSC. One of these days they’ll land on target!
Construction starts on 3 – yes, THREE Horizon-A rockets! Horizon 5 will tenatively be piloted by Jeb, Horizon 6 by Mitster, and Horizon 7 by Val!
Mitster takes off in the X-2! The flight is a success, and is a good practice run for Mitster – he checks out and is ready for piloting a real rocket! His place on an upcoming Horizon mission is guaranteed now!
The X-1 carries Mitster up, then down! The test is a success. “Wow! What a ride! I can’t wait to test out the new X-2!” Mitster excitedly says.
Designs are finalized for the X-2 Experimental Training Rocket. This craft uses the same RT-20 boosters from the Horizon Rockets, as well as the Horizon Command Pod, but features larger wings for more stable flight.
The X-2 is designed to reach orbital altitudes to simulate launches, and for pilots to practice re-entry and splash down! Mitster will be its first pilot… once he’s done training in the X-1 that is!
It’s Val’s turn! Horizon 4 takes off from KSC! 
The final orbit is a very clean 80k. Nice work!
That’s quite the view!
Uh oh! As some scientists had warned, the science pods on the side of the reentry capsule were exposed to excessive heat, and exploded as Val entered the atmosphere. “That loud bang was quite the scare! Not something you want to hear as you see fire out the window!” 
Val and the Horizon 4 pod set down nicely in the desert, and recovery teams head out to rescue her. Not a perfect mission, but a success!
Meanwhile construction of an X-1 begins to use in training. Engineers also begin designing an X-2, as a more capable short range training rocket. Mitster is excited to try out both!
The new Horizon-A rockets are ready and Jeb and Val are itching to try them! The first is named Horizon-3 and if everything goes well, it will be the first craft to orbit Kerbin! 
The first two stages fire, and take Horizon 3 into a good apoapsis of 86k!
At apoapsis the LV-900 fires, and Jeb pilots the craft into a nice stable orbit (somewhat sloppy though, without the assistance of computers!) 
Mission Control radar tracking confirms it: orbit achieved! What a day! Jeb completes one full orbit of Kerbin, then aims for what looks like KSC! 
Jeb ejects the orbital section. “What a shame! It was a good ship!” he says.
Jeb splashes down west of the KSC peninsula. “Ah! So wet! I’m ready to get rescued guys!!”
After days and days of experiments and simulations, KSEA’s best and brightest think they have a good design… the Horizon-A rocket, which has even MORE solid boosters. Thankfully, the upgraded launch platform should be able to withstand the awesome explosive power of the rocket’s engines! Construction begins on two of the rockets, tentatively to be named Horizon 3 and 4. Jebediah will take the first one up, followed by Valentina!
If things go well planning can begin on even bigger missions!
Meanwhile, another new pilot has been found that just might have the right stuff! Mitster is welcomed to the team!
Engineers begin major upgrades on the Space Center launch facility. Meanwhile, scientists begin testing larger and more powerful rockets and components. Clearly to get to orbit we’re going to need a bigger rocket!
It’s not clear yet if this is the end for the Horizon missions, or if the existing launch vehicle design can be upgraded somehow!
The newly built Horizon 2 is launched! This time rookie pilot Valentina will be in command. The goal is still orbit!
It’s getting toasty! Before firing the next stage Val had to let the craft coast a short time to avoid overheating.
Horizon 2 reaches a new record altitude… 82km! Sadly the Horizon just doesn’t seem to have the power to get much beyond the initial apoaspsis. 
Val sets down safely, and the Horizon 2 pod is recovered. KSEA engineers start working out how to get past this obstacle!
Kerbal States | Kerbin Space Exploration Administration 