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March 29, 2009

Sustainable Earth Observations and Space Exploration

by brainoids

I don’t plan to use this space often to write about work-related topics, and think it would be inappropriate to do so for anything within NASA’s current congressionally authorized mission. There are, however, a couple of “far downstream” topics I do feel strongly about, and occasionally will hit them here. So long as no one on the Hill is (yet) paying us to work them, I believe they’re fair game for a private blog.

A Game-Changing Capability

Politics-willing, within the next decade the United States will regain a strategic capability it lost nearly 40 years ago when we ended the Apollo (and Saturn) programs, namely truly heavy-lift launch capabilities. The Shuttle is an incredible launch system, but can only deliver a fraction of the mass to (low earth) orbit that the old Saturn V’s could. NASA’s Ares V “big heavy”, a key element of our Constellation Program to return to the moon, and establish a human-tended outpost there, will restore that heavy lift capability and then some.

The lunar exploration program is exciting enough in its own right, but the prospect of once again having heavy-lift capability has many forward-looking scientists fairly dialed up about the possibilities as well.

Astrophysicists are picturing, in the 2020’s-2030’s time frame, truly mammoth new observatories which literally dwarf the Hubble Space Telescope. (For those who have seen the engineering model of Hubble at the National Air and Space Museum, which towers in one exhibit hall, think that size scaled up by a factor of 3-4). For astrophysicists, it’s size (width) that matters – wider optics unlock the ability to peer deeper into the universe (and hence earlier into its evolution). Wider is heavier, and a “big heavy” Ares V launcher allows optics never-before dreamed of.

Planetary scientists see the new vehicle as bringing the outer solar system a large step closer to home. For them, the game-changing feature of Ares V is mass: the “heavy” in heavy lift allows much more complex robotic probes reaching their destinations more quickly, with more fuel/power, longer missions, and greater telemetry, not only visiting Jupiter and Saturn and their moons, but someday even bringing bits of them home to Earth to study.

Whither Earth Science?

Amidst this excitement, we might expect earth scientists to also be scrambling to invent new concepts to tap the game-changing capabilities of an Ares V. But the climate and earth science community has responded with a big yawn, barely even aware that the launch world will soon radically change. Part of this is due to the way our current science “machinery” works: the National Research Council has just finished its first Earth Science “Decadal Survey”, which lays out the new instrument and mission priorities for the 2010-2020 time frame. These include development of a long list of exciting and important – but short-duration – new missions to probe different aspects of the earth system from space. In short, the numbers have been handed out at the deli counter, and everyone is figuring out what to do while waiting their turn. The world beyond 2020 as yet holds little interest.

This disinterest is not surprising; the earth science community is challenged enough in developing instruments to explore the earth and climate system in new ways and with ever-higher precision. Cost overruns in earth science missions are, perplexingly, systematically higher than planetary or astrophysical science missions (my own suspicion is that we push then envelope of earth science instrument technology advances so aggressively that what should be the simplest, close-to-home space missions to develop end up being some of the highest risk). In such a world, heavy lift doesn’t sound very exciting, since we can barely afford the systems we launch with “conventional” rockets.

A Broken Business Model?

This, however, is precisely the problem. The current national “architecture” – or, perhaps, “business model” – for earth science and climate observations is fundamentally broken. To oversimplify: NASA develops a number of “neat new toys” which fly short-duration missions to peel back different corners of understanding of the earth system. (Make no mistake, these toys do enable critical basic science research, but ultimately they are “lab experiments”, not long-term campaigns). In an ideal world, these get “operationalized” and handed over to NOAA to develop into long term, stable, systematic measurements – the baseline against which we can measure earth system change. Continuity, stability, and quality (precision) are the most fundamental requirements for orbital observations of the earth system, if what we care about is understanding its natural and human-driven change. These requirements are precisely what we do not achieve with today’s business model – beyond the same few “core” observations we’ve measured for decades – because the “handoff” to operationalization doesn’t happen. The business model that has self-evolved (and I say “business model” intentionally, since fundamentally it is a model that “feeds” funding to the earth science industry of scientists and government labs) has placed novelty (new capability development) at the top of the requirements list, trumping continuity, stability and quality. The simple truth is there is not – and will never be – enough funding to meet all of those requirements at once in the same architecture, and while the current approach has significant forward momentum, it provides little in the way of sustainability.

The current plan for continuous, systematic measurements underscores this breakage. NASA’s core “EOS” low earth orbiting satellites (Terra, Aqua, Aura) were emplaced around 2000 and were not designed for long term missions. The “replacement” system, NPOESS, being designed by NASA, NOAA and DoD will not be ready until the middle of the next decade, again features individual satellites with fairly short lifetimes, and has development costs which are already spinning out of control. Relatively modest changes in budgets have also led to de-manifestation of critical sensors, threatening significant holes in our long-term climate baseline record. Once again: this is not a sustainable business model. Only a few brave souls are thinking about “what comes next after NPOESS”, and radical architecture changes are not currently in the trade space. The time for such thinking is now: flagship development efforts are generational, and as the “next big thing” nears its development phase, we already need to be thinking about the “next next big thing”.

Which gets, finally, to the punch-line: What could (or should) earth scientists do with a new national game-changing strategic capability (heavy lift launch)? I think the top-level answer is straightforward: tackle the greatest challenge, namely, the broken business model. The answer isn’t as sexy as huge new astrophysical telescopes, or wonderful new complexity in planetary exploration missions, it’s much more mundane: design for continuity, because continuity of earth system measurements is “what it’s all about”.

Sustainable Observations

Rather than using the huge new mass capability of an Ares V to develop wider apertures or antennas (higher resolutions, new bands), we can apply it towards longevity, and build Earth science observatory platforms and instruments which:

  1. Are “fueled up” to maintain their orbits for very long missions (apply mass towards fuel).
  2. Are refuel-able, whether through human or robotic servicing missions (apply mass towards grappling or docking systems).
  3. Are highly rad-hardened and shielded, to protect against degradation and failure of systems by the harsh space radiation environment (apply mass towards shielding).
  4. Are highly redundant, with few or no “single string” systems (apply mass towards redundancy).
  5. Are, like Hubble, upgradeable, by human or robotic servicing missions. One behemoth of a mothership would feature standardized interfaces for upgrades to core measurements, as well as “trial” measurements.
  6. It would also be very interesting to scrub the current and planned sets of Earth observations and determine how many could be achieved with “shared front end optics” followed by split back-end detectors.

To demonstrate this has value from a business/architecture perspective, we’d have to document how much of the total long term national investment in earth/climate observations using the “many short standalone missions” model goes into building what may be redundant buses (platforms), redundant optics, intercalibration and validation efforts, etc.

A side-benefit of the mothership / observatory approach is true co-location of measurements, which any earth scientist knows provides a nonlinear return on investment for the same observation. The TRMM mission is a perfect example.

The elephant in the room, of course, is “how do we avoid the NPOESS debacle” in such a model (massive cost growth and de-scoping of capabilities). I think the answer lies in holding to the postulated top-level requirements: continuity, stability and quality. This would not be a Christmas tree off of which we hang the most bleeding edge, riskiest instruments; but a generational national investment in climate measurement. Anything hung off this Christmas tree would be required to follow best practices of mission cost containment: disciplined and restrained requirements development, extended Phase A’s and Phase B’s before development, stringent requirements on component technology heritage and maturity (TRL), extended testing, etc.  The associated costs or this more ‘measured’ approach are borne by weaning ourselves from the current rush-to-fly-the-next-toy-and-maximize-the-number-of-toys architecture, with all of its redundancies and cost inefficiencies.

“Building a tank” is by no means the most inspirational pitch for leveraging a new heavy-lift launch capability towards benefits here on Earth. But perhaps there’s a highly relevant message in the subtext: as the country (and hopefully world) slowly revectors towards awareness that our Earthbound practices must begin to embrace sustainability as a fundamental design principle, we should be applying that same thinking to our space-based monitoring of the Earth itself. “Ares V for Sustainability” – sustainability of the architecture, and business, of earth observation – is a slogan I can get behind, and even get fired up about.

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