The case for the 20MT rocket
- Paper number
IAC-05-D2.1.09
- Author
Mr. Sandro Catanzaro, Massachussets Institute of Technology (MIT), United States
- Year
2005
- Abstract
The recently announced exploration of the moon and Mars requires an The recently announced exploration of the moon and Mars requires an unprecedented mass to be lifted to Low Earth Orbit (LEO), in the range of 300 to 1000MT per mission, aspect that could be solved either through:
- The design and construction of a new launcher with a payload in LEO in the range of 40 to 200MT, so called the Heavy Lift Vehicle
- The use of an increased launch rate of already operative Medium Expendable Launch Vehicles (MELV), such as Delta IV H, Titan 4, Ariane 5 and Proton K with a capacity to send 20 to 25 MT of payload in LEO
The analysis in this paper, based on Economic, Innovation, Policy robustness, and Technical considerations, concludes that:
- The usage of the existing MELV with a maximum capacity of 20 to 25 MT payloads in LEO and launch rates of 100 per year is a better alternative.
- Decoupling of launcher and payload through standard interfaces, (among them the payload size), will allow for a modularization and commoditization of the market. As a result the launch risk and cost will decrease, and the innovation pace at both sides of the interface (payload and launcher) will increase.
- The evolution towards larger vehicles could be assessed later based on real demand, once 20MT market has been developed.
Economic considerations Year 2003 statistics show that the commercial market demand is skewed towards vehicles of small size, with masses above 15MT on less than 20
By using a smaller vehicle with a high launch rate, the entire aerospace supply chain will be subject to a faster pace, with relatively smaller components, allowing for an increase in competition, and thus a reduction in costs as a result of faster learning curves, and mass production techniques. Furthermore, it will help increase the overall industry asset utilization ratio.
Technology Strategy and Innovation Innovation at the Aerospace Industry is slow, and increasing payload masses will make it even slower, because of the higher cost of support systems, and complexity. By increasing the rate of launches of the existing hardware the development speed of the industry will increase.
In this unique case of technology disruption, the incumbents might be tempted to build an even larger launcher, for what seems to be an underserved market, in terms of payload size. This new hardware would be disrupted by a smaller MELV launcher through the reduced risk and increased responsiveness that a high launch rate strategy enables.
Safety An increased rate of launch will decrease the risk, by allowing a faster learning curve. Besides, a smaller vehicle is less complex, thus has a lower inherent risk. The need for man-rated vehicles can be addressed through an escape rocket on a crew capsule launched by non man-rated vehicles. Smaller, non unique and easier to interface hardware and a high launch rate will allow to assemble a rescue mission in short notice, using international partners hardware and launch pads if needed.
Robustness against Policy changes By using hardware that is already developed, the Space Exploration Initiative will allow the Aerospace Industry to bid with lower uncertainty, providing faster benefits to the public. Additionally, it will allow the industry to focus on subsystems that need further development, allowing for an earlier delivery of value of the system, and as a consequence bigger support from the public.
Furthermore, by reducing the size of the average payload at risk, the time frame to recover from a launch failure will be lower, not jeopardizing the program as a whole.
Technical Considerations A mass penalty due to a less efficient payload packaging and additional mass because of hardware and fuel for docking is one reason in favor of a bigger launcher. The maximum possible penalty would be 50
Another technical reason that supported the decision for larger payload was to share the costs of unique hardware across larger payload sizes. Nowadays, control systems are less expensive, there is a high fraction of software development (with a marginal replication cost), and there is relatively low impact of the variable costs against the fixed costs of launching.
- Abstract document