KerbalX

Details

• Type: VAB
• Class: ship
• Part Count: 43
• Mods: 2
• KSP: 1.11.1

Mods

• Bluedog DB
• Squad (stock)

The Atlas rocket began life as the first ICBM developed by the United States in response to the development of the R-7 Semyorka and was first launched in 1957. It had a fairly short deployment life as an ICBM since it was rendered obsolete almost from the beginning and they were taken out of service by 1965. However between 1957 and 1959 it was chosen to serve as a space launch vehicle, much like the Redstone, but with the capacity to handle larger payloads including orbital manned flights.

The development of upper stages hit some early delays with the initial plans to develop the Vega upper stage being cancelled, three separate launch attempts with the Able failing, and finally it was paired with the Agena. This first generation of Atlas rockets would largely be modified Atlas-D missiles and given the designation of LV-3-A when paired with an Agena, LV-3-B for orbital manned flights, and lastly LV-3-C for the eventual Centaur upper stage.

The success of the LV-3 series’ led to its second generation which began with standardizing the launch vehicles which had been individually tailored for their payloads in the first generation. The introduction of the SLV-3 (standardized launch vehicle) reduced costs and sped up preparation of missions by requiring each mission to conform to a single Atlas standard. The later part of the second generation which was converted decommissioned Atlas E and F missiles into launch vehicles, further upgrades with Atlas G and H, and lastly a commercial version of the Atlas G/H known as the Atlas I.

The third generation Atlas II was first launched in 1991 as a USAF lifter and, among other things, eliminated the Vernier engines on the sides of the booster skirt and replaced it with a single roll control thruster on the interstage adapter. It would be developed into a commercial launcher, the Atlas IIA and lastly a version with four Castor 4A booster rockets known as the Atlas IIAS. The last third generation rocket, the Atlas IIAS was launched in 2004 before it was finally retired.

The fourth generation Atlas III, along with its larger cousin the Atlas V, began development in the 1990s as part of the USAF’s Evolved Expendable Launch Program (EELP) to continue delivering military payloads into orbit (and beyond). The Atlas III would overlap and replace the highly successful Atlas II and finally replace the classic stage-and-a-half design with a more normal staging process courtesy of twin Russian-built rocket engines. It wouldn’t have a long record as it was essentially a stop-gap measure for the larger and more powerful Atlas V. Nevertheless it had a successful history of six launches which carried the Centaur II and the newer Centaur III in both single and double engine configurations.

The Atlas III was initially paired with the Centaur II which had been previously developed for the Atlas II but also saw the first operational use of the Common Centaur (Centaur III) that would also be used on the Atlas V. The common designation comes from the fact it uses the same engines as the more recent Delta stages to help cut costs.

The Bossart III-A is an approximation of the Atlas III/III-A made by Bluedog Design Bureau and as such replaces the classic Atlas design. It is no longer the stage-and-a-half design but a more normal first stage engine and as such you no longer have to worry about jettisoning the booster skirt. It is considerably more powerful than the Bossart II as it uses a modification of the engines also used on the Bossart V.

The III/III-A designation refers to the fact it still uses the Inon II used on the Atlas II in a dual engine configuration. It operates the same as on the Bossart II and is optimized for burns in the vacuum of space.

I have re-used the 2.5 tonne heliocentric payload from the Bossart II as both vehicles are meant for similar performance. You should notice that the engines are considerably more powerful with the first stage putting the payload into space. It should burn until exhausted after which the Inon II will take over the rest of the burns.

Built in the VAB in KSP version 1.11.1.