Launch vehicles formed a significant part of the launching mechanism of a number of satellites into space for different purposes. Since the functions were different, launch vehicles had a lot of option for customization which resulted in a huge number of variants that could be used. However, due to a number of disadvantages associated with these variations, the excessive costs being the major one, launch companies are now resorting to standard vehicles which are smaller and more efficient.
One of the major launching companies called the United Launch Alliance were the forerunners in providing vehicles with maximum customization in its Alpha and Delta models. The differences were mainly in the fairing of the payload and the number of solid fuels strapped on to it. However, it cost the company and the agency sponsoring the launch, most of which were government missions, a lot of money, making it almost unfeasible. Till around 2 years ago, the company offered as many as 44 variations in its launch vehicles.
However, because of the complexity of the designs and the need to perform complete and cumbersome tests each time a new variation was used, ULA has now brought down their number to 18. They plan to continue to do more cut downs and start with implementing it on Vulcan Centaur which is slated to release by 2021. The initial models are estimated to have two payload fairings and variations in the fuel strap-ons of 2,4 and 6. They believe the final model will settle somewhere around 4 boosters.
Another launch company called Blue Origin is taking the simplification by its neck by developing a vehicle called New Glenn that will have the same configuration for all kinds of runs. They believe it will make launches much more simple and cost effective. There will be sufficient performance margin as well, that is, there is will be excessive leftover space which can be used for other purposes.
Brett Alexander, vice president of the government sector of Blue Origin believe that the main aim of the company is to launch as many vehicles as possible, irrespective of it being half empty in order to maximize its utility.