Saturday, November 21, 2009

Ten Questions for HSF Committee - Question 9

Should we reach the end of the Flexible Path as quickly as possible, or should we make the most of each step along that path?

The Augustine report describes the Flexible Path as an incrementally more ambitious and difficult series of deep space missions. The wording of the Flexible Path description seems to indicate that, while exploration capabilities increase gradually on this path, there is little infrastructure built up from mission to mission, and little long-term use of the various deep space destinations. In a sense the deep space missions could be considered "one-offs" that eventually allow us to reach the surface of Mars. For example, the report says

In every flight, the Flexible Path voyages would visit places where humans have never been before, with each mission extending farther than the previous one ...

Clearly, if each mission extends farther than the previous one, we are not lingering at the various destinations.

The report describes several missions to near-Earth objects, but each near-Earth object is a unique destination. The other destinations don't seem to imply or require repeated visits. It is suggested that the Earth-Moon L1 point destination might involve a fuel depot, but no other space infrastructure is implied in the Flexible Path.

I would suggest that the Flexible Path be modified to potentially revisit earlier destinations as appropriate for
  • building space infrastructure such as small habitats or stations, depots, servicing nodes, and assembly areas to enable exploration and resource use

  • additional science benefits such as improved data gathering following analysis of data from earlier Flexible Path missions

  • incremental improvement of engineering and science capabilities at each destination, such as additional observatory servicing capabilities, additional telerobotics missions, and improved science instruments

  • making later exploration steps safer, easier, and more productive through carefully repeated testing of exploration systems at each Flexible Path step and build-up of exploration-enabling space infrastructure

  • more thorough extraction of resources at NEOs if the early NEO ISRU demos show promise

  • enabling commerce and purchasing commercial services at the various destinations
The Flexible Path should specifically spell out options for gradually passing over responsibility for earlier destinations to commercial space without having the space agency completely losing interest in those earlier destinations.

In a limited budget, the adjustment I've described would come at a price. Our journey along the Flexible Path would be slower. That's not a trivial price. However, a slower journey is probably justified if it results in getting more benefits out of each step.


Paul Spudis said...

The problem with "Flexible Path" as outlined in Augustine is that it is merely another form of the existing (Apollo) paradigm -- stunt PR missions to somewhere, followed by abandonment and the next stunt. Dumping lunar outpost does not solve the agency's fundamental problem but rather exacerbates it -- more and greater space thrills and "firsts," followed by public ennui and a new lobbying campaign for the next "step" beyond LEO.

This mode of business leaves no legacy infrastructure and develops no resources. We continue to launch everything from Earth and continue to be mass- and power-limited and thus, capability limited.

Ray said...

Dr. Spudis:

I think there is some value in the Flexible Path as described in the report, with "each mission extending farther than the previous one". Each mission would by that definition allow us to pursue longer missions, which we will eventually need to do. Each mission will also do valuable science and engineering jobs. However, I would much rather see a variant of Flexible Path, if that's the path that will be chosen, that

- develops infrastructure as appropriate at various deep space destinations (eg: lunar orbit, GEO, Lagrange points) that would be used repeatedly later as we build capabilities

- develops resources at those destinations as appropriate (eg: NEOs, Mars Moons, lunar surface starting with robots)

- develops capabilities at those destinations as appropriate (eg: refueling, servicing, assembly, reusable in-space spacecraft, tugs, and landers)

- passes capabilities and responsibilities as appropriate to commercial space as NASA goes outward

If that doubles or triples our time going down the Flexible Path, then so be it.

I also think the years leading up to human exploration missions should be a time of vigorous robotic exploration and testing in areas like lunar resources, ISRU demos, and site preparation, leading at some point to the Augustine report's Flexible Path off-ramp for astronauts on the Moon. Depending on how the early lunar resource trials go, this could lead to a lunar outpost with a commercial emphasis. Again, if all of that lunar robotic work slows down the Flexible Path somewhat, I think it's a price worth paying.

I'm not against an approach like the Flexible Path; in fact I think it has quite a few merits. However, I do think the raw idea from the report should be shifted somewhat to make the most of the steps along the way - including the lunar surface. I don't have a huge preference for initial destinations; I'm more concerned about the "how" than the "where". In my opinion, the "program of record" shows Moon First can be a disaster, but the type of Moon First approach you've written about would have great prospects of returning considerable value at many levels. Flexible Path could probably also be done well ... or not so well.

Paul Spudis said...

Hi Ray,

I am in agreement with you that FP could offer many benefits for creating real space faring capability, including L-point staging and fuel depots. My point is that NASA as an entity has demonstrated itself incapable of implementing Flexible Path in such a manner as you have outlined. As you well know, with the VSE, they were given specific programmatic direction not only to go to the Moon, but to learn how to use its resources to live on another world and create new space faring capability. Instead, they offered up a re-packaged version of Apollo, complete with expendable spacecraft and no legacy infrastructure. How likely do you think it that they would suddenly abandon the Apollo template for an incremental, cumulative approach?

The problem is not the destination, it's the mindset of the program implementation. And that has not changed and will not change, whether your destination is the Moon or an asteroid. FP as implemented by NASA will still involve big rockets, huge programs, and throw-away assets. You want proof? Two examples: ESAS and Augustine.