Prometheus II-Leo Vinci
by gc1ceo
uploaded 2016-11-22
(updated 2017-12-28)
mod ship
#titan #gemini #prometheus #leo


  • Type: VAB
  • Class: ship
  • Part Count: 29
  • Mods: 2


  • Bluedog DB
  • TweakableEverything

The early successes of the Mercury program provided that astronauts could be sent into Earth’s orbit and returned safely and that necessitated a new program to focus on procedures and technologies to approach more lofty goals. It was clear that any moon landing would require multiple crew members but Mercury still partly lagged behind the Soviet program since it only allowed for a single pilot and had technological limits to what it could achieve. Once the final Mercury mission conducted it bought an end to two years of America’s early spaceflight. Project Gemini had a number of advantages over Project Mercury since there was now a cadre of experienced astronauts, technicians, and designers who all had a hand in the design of the Gemini spacecraft.

There were a total of twelve manned Gemini missions, each with two crew members, over the course of two and a half years with the longest mission lasting a full two weeks. The project start countless firsts such as America’s first space walk, successful rendezvous and docking operations necessary for future Apollo missions, and the ability to address potentially catastrophic failures such that happened with Gemini VIII. By the end of Project Gemini the American space program caught up or surpassed many of the early Soviet victories and cemented America’s journey to the moon as simply a matter of when.

A new launch vehicle was developed for Project Gemini used a modified version of the Titan II ICBM which exceeded the payload capabilities of the Atlas launcher and continued to began a whole family of launch vehicles which would be used for many decades. It was the first truly multi-stage launch vehicle to be used for American astronauts as the Redstone rocket was a single stage and Atlas was a stage-and-half launcher. It became the first American launch vehicle not developed exclusively as a manned launcher which caused a few minor problems for astronauts with some remarking the ride to space was, at times, even rougher than the Atlas or Redstone launches.

The Leo space capsule is Bluedog Design Bureau’s equivalent of the Gemini space capsule. It’s designed for a crew of two Kerbonauts and combines several Gemini spacecraft features which were initially part of different missions. It has an internal monopropellent fuel cell which allows for extended orbital missions as well as a docking port which wasn’t part of the earlier Gemini missions. The spacecraft also has its own engines unlike the earlier Hermes capsule which are meant for rendezvous and docking operations but can also be used to change orbital parameters and to de-orbit the spacecraft. I have somewhat reduced the weight of the heat shield but the remaining ablative should be more than enough for any kind of re-entry. I have also removed some of the fuel from the second stage to allow a wider margin of error while still in the upper atmosphere.

The ascent profile is rather simple but there is a lower TWR (Thrust-to-Weight Ratio) so the ascent may be a bit fuel inefficient and may require as much as 4000 DV to achieve an orbit of approximately 150km. The first stage should get the payload into the upper atmosphere, nearly to the edge of space, and afterwards the second stage will take over the rest of the ascent and orbital process. You may encounter some unexpected yawing and other flight disruptions at the beginning of the second stage and potentially also when you clear the atmosphere. I recommend just riding out the ascent and not worrying about these effects unless it has a serious effect on your trajectory. The problems should completely clear once you have completely cleared the atmosphere and the second stage is very maneuverable once in space.

The second stage should be decoupled once you reach your desired orbit although there’s no real harm in keeping it attached if you wish to further adjust your orbit. The retro-rockets attached to the second stage may not have enough power to send the second stage into a decaying orbit which for lower orbits it shouldn’t be a problem. The Leo’s monopropellent engines aren’t very powerful so you take that into account when planning any orbital maneuvers such as a rendezvous with another craft.

The re-entry procedure is currently simpler than the real-life Gemini (or the Gemini from FASA) and you simply fire your engines retrograde. The Medici service module needs to be decoupled either manually or through the hot-key since it can’t be staged. It should be decoupled just as you are beginning your re-entry and should completely burn up in the atmosphere.

Built in the VAB in KSP version 1.3.1.

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