In-Space Propulsion Using Modular Building Blocks v2.0

The use of modular building blocks for high-impulse in-space chemical propulsion offers several advantages over the traditional built-to-order approach. One advantage is that economies of scale can be achieved in the manufacturing, launch, and operation of the propulsion hardware. If the same building blocks can be used for diverse delta-v events, there will be some savings in the overall design and production effort. Another advantage of using multiple building blocks for propulsion is that they can be launched without a super heavy lift launch vehicle. If the propellants can be stored in space for long periods, then launch schedules will not be critical to mission success. Storing propellant on-orbit in reconfigurable building blocks allows for the rapid generation of custom propulsion stages. Finally, using building blocks is simpler than using refillable depots because it doesn't require transferring propellant in microgravity.

More information: https://docs.google.com/open?id=0B2jx-yqkRjqKM2UyZmQ5MjgtOGY1MC00N2M5LWFkODMt...

©2011 by James Doehring
Feedback appreciated. james.doehring@gmail.com

Category:

Science & Technology

Tags:

• spacecraft propulsion
• modular
• propellant depot
• propellant feed system
• storing propellant
• in-space
• low earth orbit
• space exploration
• delta-v
• moon
• mars
• nasa
• 3ds max

[jamesdoehring]

@trivvity Apart from the cost issue, depots can offer more operation flexibility than a single-design heavy lift rocket. There are many smaller rockets on the market, so if one of the them develops a problem, we can switch to another without significantly disrupting launch schedules. If we're using only one design for a massive heavy lift rocket, a mishap will ground the space program for years.

[jamesdoehring]

@trivvity Fuel and oxygen actually represents about 1% or less of the cost of a rocket launch. A lot of the cost is in paying the salaries of the people who design and manage the rockets. These costs are essentially fixed whether the rockets launch 10 times or 1000 times. It seems likely to me that smaller rockets will prove cheaper due to the economies of scale associated with a greater launch frequency.

[jamesdoehring]

@trivvity That's a great question, trivvity, but it applies to the more general debate on using a heavy lift launch vehicle vs. a number of smaller rockets. This is an empirical question that will be decided over the next few decades. The way I see it, your question can be rephrased as "Is the cost per pound of payload to orbit cheaper using one large rocket or several smaller rockets?"

[trivvity]

I am curious, however, if the extreme cost of launching fuel-tanker rockets up to re-supply the orbital fuel depot will cost more than the depot will save? In other words, to make this happen, there would be many rocket launches to carry fuel tanks up into space. Each of these rockets would burn a lot of fuel and cost a lot of money. Might this cancel out the original intent of saving money for fuel/launch costs?