Anthonares

Few scientific challenges are more important than determining if life on Earth is alone in the universe. Over the last ten years we have found almost two-hundred extrasolar planets, but none that seem likely to harbor life as we know it. Such life requires (as best as we know) a solid surface, above-freezing temperatures (but not too hot), limited radiation, and an energy source. Further complicating these criteria is that all four must be maintained while biological evolution takes place, which may require hundreds of millions of years for simple life, and perhaps billions of years for intelligent life. (Images Credit: JPL, NASA)

One way to satisfy all of these requirements is to search for terrestrial planets of about an Earth mass, that receive about the same level of solar energy that Earth does, and that orbit stars that are stable over a period about as long as our sun has been. This may be the most unimaginative search for extraterrestrial life scientists could come up with, but it’s also the one that would be guaranteed to detect life here on Earth. Since we only have one sample of life’s existence, we must base a scientific search on that fact.

The Terrestrial Planet Finder (TPF) as currently envisioned by NASA is actually two separate missions, TPF-Coronograph (TPF-C) and TPF-Interferometer (TPF-I). TPF-C had been planned for launch in 2014 to be followed by TPF-I in 2020. But last Monday we got our first glimpse of the President’s FY 2007 budget requests, and because of the burgeoning costs of manned space exploration TPF has been delayed indefinitely.

The TPF missions are far too important to be delayed indefinitely, indeed they are far to important scientifically to be funded through NASA. Large ground-based observatories are funded through consortia of universities, governments, and private groups, and so too should the TPF missions. Funding, building, and operating the TPF missions outside of NASA would provide the scientific community greater insulation against the budgetary whims of the federal government and against the degenerating mission creep that is gradually undermining every NASA endeavor.

The Terrestrial Planet Finder(s)
The TPF mission was originally proposed by NASA in 1999 to great excitement in the scientific community. In May 2002, NASA selected the TPF-C and TPF-I missions for further study and development. Both missions required significant engineering and technological advances before they could be launched, so a target launch date of 2014 was set for TPF-C, and TPF-I would follow sometime later, not before 2020.

The TPF-Coronograph is a large infrared telescope with an instrument called a coronagraph that blocks out the light of a central star in order to see the much dimmer objects surrounding it. It was named for the purpose of studying the Sun’s corona which prior to its invention was possible only during solar eclipse. The coronagraph on TPF-C would be heretofore unprecedented in its precision, but mission engineers are confident that technological advances on Earth will make it feasible before 2014. The left-hand image above shows a simulation of the TPF-C output if it were looking at our solar system from a distance of 33 light-years.

The TPF-Interferometer is actually a flotilla of telescopes whose signals are precisely combined in order to cancel out the light of a central star. The right-hand image above simulates what Earth would look like to the TPF-I from 33 light-years distant. They would be precisely aligned by lasers (such as in the ground-based LIGO system, funded by the NSF) while their positions are maintained by an as-yet undecided propulsion system. The guidance and propulsions systems must achieve fantastic accuracy, meaning that the TPF-I technologies must be given more time to reach maturity than was the case with TPF-C. Still, the TPF-I mission is not exactly pie-in-the-sky technology, the European Space Agency is planning a similar mission dubbed Darwin to be launched even earlier than 2020.

For more information, visit the JPL site of the TPF missions. It contains a wealth of information including some surprisingly readable engineering reports on the technical feasibility, mission precursor science, and mission science goals.

Why Not NASA
NASA is an agency plagued by an extremely successful period in its history. All current accomplishments are compared to the Apollo glory days, and often found lacking. But it wasn’t necessarily the pluck of those young engineers or the determination of Cold-War politics that led to Apollo’s success. During the Apollo era, NASA effectively had three missions: 1) fund and conduct aeronautical research in support of human air- and space-flight, 2) conduct simple cheap robotic missions to explore the closest planets and the moon, and 3) prepare for a manned lunar mission through the simplest means possible. Compare this to NASA’s current missions which vary for each field center and include earth observation, aeronautics research, launch vehicle development, ISS construction, Shuttle maintenance, planetary exploration, planetary- and geo-sciences, astrobiological research, and probably a dozen others. Other government agencies such as the NSF and the NIH have broad objectives as well, but they are primarily funding agencies not in charge of execution and operation. Thus while the missions of those agencies are in some ways broader than NASA’s, their goals are far simpler: find, fund, and oversee successful scientific and medical research.

NASA is focusing much of its budgetary resources on manned spaceflight as it must if the Vision for Space Exploration is to succeed while it completes the ISS as well. However, this has squeezed tremendously important science missions like the TPF, the Stellar Interferometer Mission (SIM, a TPF precursor), and the Europa mission off the launch docket. Unfortunately in this time of human-induced climate change, Earth observation is suffering as well, depriving scientists and policy makers of vital information.

Meanwhile, the Large Binocular Telescope, the Large Hadron Collider at CERN, the Laser-Interferometer Gravity Observatory (LIGO), and dozens of other major physics and astronomy facilities have been completed successfully. NASA’s budget crunch hasn’t affected these facilities because, of course, they are not NASA facilities. They are managed by universities and consortia of governments and private financing. Scientists petition for time at these facilities and in some cases “buy time” through the use of grant funding from other sources. They are all scientifically important facilities, but none of them near as much as the TPF (in my opinion at least). Why, then, hasn’t the TPF been built? Because NASA is in charge of its funding.

Where Do We Go From Here?
My point in writing this entry is to raise the profile of the TPF and to help fuel the discussion about NASA reform. As I’ve previously written (here and here), NASA needs to be separated into two or three completely separate entities. Manned space exploration should be its own entity, justified on its own exploration and colonization merits (the Manned Space Exploration Administration). Robotic interplanetary space probes and Earth Observation should be another agency (The Space Probe Science Adminsitration), and NACA ought to be revived as a third daughter agency. (Image: copyright Anthony Kendall, see terms below)

Gradually, constructing, launching, and operating missions in Earth orbits or in Lagrange points should be taken over by consortia similar to those that operate ground-based facilities today. As commercial satellite companies have demonstrated, they are more than capable of managing their own facilities. NASA’s deep space expertise will necessitate the existence of an unmanned space probe agency for several decades at least, and perhaps indefinitely as we look to explore the stars. The TPF missions could be the first in step in this process. If the scientific community wants them badly enough, they have the lobbying ability (as demonstrated with Hubble and New Horizons) to get Congress to fund them. Since private consortia will not have billions extra to absorb cost overruns, TPF will be constructed and launched quickly and more efficiently than within the stifling NASA bureaucracy.

If the TPF is constructed this way it will provide a powerful example that will force the question of why NASA manages near-Earth missions at all. If science, not exploration, is their primary goal, then they should be paid for and run by scientists. Hopefully this would catalyze the division of NASA into agencies more capable of accomplishing their much-reduced missions.