Hermes Rocket Family

The Hermes Rocket Family is a fifth generation disposable Heavy Lift Launch Vehicle, designed specifically for KASA, using legacy Explorer-Shuttle Derived Components. The Hermes rockets is designed with interplanetary missions in mind. In particular, the Hermess are meant for the eventual manned landing on Duna.

The Hermes is one of the most versatile platforms, offering a large variety of launch options. This allows for easy customization to whatever mission parameters. Developed by VVA, Rockomax, and Kerbodyne, the Hermes is commonly compared to the Agera-Class Spaceplane.

Design History:
The Hermes Family Rockets origins start with the cancellation of the Explorer-Class Shuttles. With the cancellation, KASA lost its ability to put kerbalnauts into space and SpaceLab.

Additionally, KASA had begun a new directive to not only revisit the Mun, but also land Kerbals on Duna.

A resulting internal memo found the need for a new Kerbalnaut rated heavy lift rocket, with super heavy capabilities.

The Hermes Rocket Family was the response to the memo, whose variants would be capable of meeting different aspects of KASA’s requirements.

Developed by a coalition of VVA, Kerbodyne, and Rockomax, the Hermes is the most versatile and powerful rocket in KASA’s inventory.

Across the board, the Hermes Family has relied heavily on proven technology to help drive costs down.

Hermes I
The Hermes I was the smallest launch vehicle in the Hermes family. The Hermes I was developed to meet the initial need by KASA to have a Kerbalnaut rated rocket to allow for Kerbalnaut access to space, and SpaceLab.

The Hermes I design was essentially a modified Alpha Series Booster from the Explorer Series. Since KASA did not have a modern Capsule design, the Hermes I actually launched with the legacy Thor CSM, used in the Artemis program to Duna.

The Hermes I was only launched twice before being shelved. The Alpha booster had never been intended for the application, and the vibrations were so rough they were deemed dangerous.

Additionally, the Rockomax Trojan III Rocket has begun Kerbalnaut certification and the initial test flights were much more promising over the Hermes I.

Finally, the Orbital Vehicle X program for a Explorer replacement had selected the Kerbalnaut capable Agera-Class Spaceplane.

Hermes II
The Hermes II was developed specifically as a test bed for later iterations. The Hermes II was the first S3 size rocket of the family, something that would continue onto later versions.

The Hermes II relied super heavily on legacy Explorer-Era components. The main rocket body/tanks were based heavily on the Explorer Shuttle external tank.

Additionally, the Hermes II was powered by KS-25 “Vectors”, the same engines used on the Explorer.

Even it’s Upperstage relied on current technology, as it used the Argo III Upperstage.

The Hermes II never reached Kerbalrated flight status, as after its 7th flight it was retired in favor of the new Hermes III.

Hermes III:
The Hermes III is the smallest Hermes currently in use. The Hermes III is the base for which the later Hermess are developed from.

The Hermes III was heavily developed from the Hermes II. A result of the success of the Hermes II, the Hermes III uses a KS-25x4 “Mammoth” engine.

The “Mammoth” had been developed by Kerbodyne for commercial sale, and was based heavily related on the Explorer’s main engines, the KS-25 “Vector”.

The KS-25x4 had actually been bought by Roskosmos and already seen limited use on the Zenith II Rocket.

The Hermes III also had the options for an extended tank, along with the optional use of legacy KD-25 Kickback SRB.

The Hermes III also saw the first use of the Argo V Upperstage, but it is still occasionally launched with Argo III Upperstages.

The Argo V was specifically developed for the Hermes, and actually used evolved Mercury era technology. The Argo V uses a single KR-2L+ “Rhino”, which is ultimately a modern evolution of the RE-I2 “Skiff” used on the Mercury Upperstages.

While the Hermes III is Kerbalnaut rated, it has only flown with Kerbals once. The Hermes III has been primarily used as a Launch Vehicle for heavy payloads into LKO, GKO, and for the launch of probes and rovers into the farther solar planets such as Laythe and Eeloo.

Hermes IV
The Hermes IV is the first of the uprated Hermess. The Hermes IV was developed from the Hermes III for Mun/Minmus

missions. In particular, the Hermes IV is to serve the purpose of putting Kerbalnauts back on the surface of the Mun/Minmus, and as the launch vehicle for components of the Mun colony, and the Opportunity Mün Station.

Like the preceding Hermes III, the Hermes IV is powered by a KS-25x4 “Mammoth” engine. However, 2 additional KS-25 “Vector” engines serve to increase the overall thrust.

The Hermes IV has an extended tank, with an optional extended+ tank, which adds an even larger supplemental tank.

This extended main tank is also reinforced to allow for the use of Alpha Series boosters. These could later be swapped for Clydesdale Boosters.

Hermes V
The Hermes V is the flagship of the Hermes Rocket Family. A further developed version of the Hermes IV, the Hermes V is the superheavy Rocket that is capable of Duna missions.

The Hermes V surpasses the Hermes IV with the addition of another KS-25 Vector. This gives the Hermes V a grand total of 7 engines in the center stack.

The additional rocket forced the need for more fuel, so the Hermes V uses the same Extended+ tank used on certain variants of the Hermes IV.

The rocket body has been reinforced even more, this time to allow for the use of Trojan IIIB as Boosters.

Finally, the Hermes V makes use of the Argo V Evo. The Argo V Evo is an evolved version of the Argo V, with an extended fuel tank for greater range.

Overall, the Hermes V has an unprecedented amount of power and range.

Hermes Variants
The Hermess are offered in a wide range of  different launch configurations to allow for mission specific requirements. The variants are specified by 3 numbers following the Hermes Family member.

The first number implies what payload configuration the rocket is set up for. The number 1 is for Manned Exploration missions, while the number 2 is for cargo missions.

The second number implies what tank size the rocket is equipped with.

The number 0 implies an Alpha Series tank size, which is only used for the Hermes I.

The Number 1 is for standard tank size, used on the Hermes II, and the Hermes III.

The Number 2 is for the extended tank, which is an option on the Hermes III, and standard for the Hermes IV.

The Number 3 is for the extended+ tank, which is used as an option for Hermes IV, and standard for Hermes V.