Propellant Depots and Thought Bubbles


“Do not believe in anything simply because you have heard it. Do not believe in anything simply because it is spoken and rumored by many. Do not believe in anything simply because it is found written in your religious books. Do not believe in anything merely on the authority of your teachers and elders. Do not believe in traditions because they have been handed down for many generations. But after observation and analysis, when you find that anything agrees with reason and is conducive to the good and benefit of one and all, then accept it and live up to it.”
–Buddha

If you’ve been following space news recently, propellant depots are in the news again.  (If you’re not familiar with “propellant depots,” consider them as a “gas stations” in space – either in low Earth orbit or in other easily accessible locations in space.)  The latest news concerns the claim that NASA internal studies show that propellant depots provide a cheaper alternative to deep space exploration than that provided by the heavy lift options under consideration during the previous summer. I’m not going to address whether the reporting is accurate, or not (and I’m sure that comes to the disappointment of the propellant depot enthusiasts out there).  Instead, I’m going to use propellant depots to address something more fundamental that I hope has benefits beyond this particular arena – examination of my “thought bubbles.”

Let’s start with these statements.

  • I have reservations about propellant depots. 
  • Something about them doesn’t seem quite right. 

These statements reflect what is going on inside my head right now concerning propellant depots.  Does this internal dialogue represent my instincts talking to me?  In this case, I don’t think so; instead, this dialogue is representative of what Holly G. Green calls a “thought bubble.”  According to Ms. Green, a “thought bubble” is our inner voice telling us the world must be a certain way, because we are filling a void of information with our own interpretation and beliefs.

To move forward on my reservations concerning propellant depots requires the recognition that I have voids in my understanding about them.  Borrowing from the typical debate format, here are three ways to fill the voids, all of which are needed here.

Facts.  Facts are those items of knowledge or information based on real occurrences, something that actually exists, or something that is known to have existed or to have happened.  Some examples of facts: “Propellant depots in low Earth orbit do not exist today.”  “We have successfully built heavy lift launch vehicles in the past, such as Saturn V and Shuttle.”  “NASA’s top-line budget, when accounting for inflation, has remained essentially flat since 2000.”  The greatest challenge concerning facts is to consider all relevant facts in evidence, not just to “cherry pick” those that support a particular position while ignoring the others.

Value.  Discussions of value revolve around whether a thing is good or bad, worthy or unworthy, just or unjust.  The typical approach to objectifying value is to identify the benefits (real or perceived) and weigh them against the cost, using the value equation: value = benefit – cost.  Discussions around value can be challenging, such as when the benefit cannot be monetized as is often the case in public sector pursuits.  (In fact, this is one of the primary reasons why a given pursuit is done by the public sector versus the private sector.)  What one often resorts to in this case is an assumption of equivalent benefit and a comparison of costs; lower cost for equivalent benefit results in a greater value.  A comprehensive discussion of value needs to address as many realistic potential benefits as can be identified, along with an honest assessment of the likelihood of occurrence of each of those benefits.  This, in conjunction with cost estimates and cost uncertainty, form the foundation of a value conversation.

Policy/Law.  We also have a body of policy and law that must be taken into account.  In the case of space exploration, we have the top-level National Space Policy of 2010, created by the Office of Science and Technology Policy and the National Security Council, that establishes space policy for the Department of Defense, NASA and various intelligence agencies. We also have the NASA Authorization Act of 2010, passed by Congress as Public Law 111-267 with exclusive focus on NASA, that states the “will of Congress” in the form of law.

What I’ve outlined here is the approach I will take to address my thoughts bubbles concerning propellant depots.  In particular, I’ll conclude with a quick examination of the policy/law side, which appears on the surface to be the biggest obstacle to the propellant depot approach.

The National Space Policy of 2010 does not reference propellant depots explicitly, although one can make the case that propellant depots fit the definition of “supporting infrastructure” if deemed as part of a “mission-essential function.”  In my opinion, if a mission architecture was proposed and planned with propellant depots in mind, such an approach could fit conceptually within the policy.  The NASA Authorization Act of 2010 actually calls out “propellant resupply and transfer” as one of several findings identified by Congress for enabling humans to move beyond low Earth orbit.  The “Congressional language” mentioned in the report is a reference to the Space Launch System cited explicitly in the Authorization Act, and a mutually-understood position between Congress and NASA that the Space Launch System takes precedence over an architecture based on propellant depots.  Although I’ll admit the latter is conclusory, I see it following from the “Top Three Priorities for NASA” stated at the formal unveiling of the Space Launch System a few weeks ago:

  1. Commercial cargo and crew for the International Space Station;
  2. Deep space exploration with the Space Launch System and the Multi-Purpose Crew Vehicle; and
  3. Completing the James Webb Space Telescope.

I don’t see propellant depots mentioned, so they aren’t a top priority for NASA.

Yet I offer that by attacking our thought bubbles and examining the facts, value, and policy/law, we might end up in a different position in a few years with regards to propellant depots.  So for the propellant depot enthusiasts out there, continue identifying relevant facts, refining your value proposition, and keep pushing for policy and law supportive of your approach.  You just might get there.

Text Copyright © 2011, Joe Williams
Photo credit: iStockphoto/4×6

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Propellant Depots and Thought Bubbles