The U.S. government has been gambling with the Landsat satellite program for years, first waffling about whether to build another dedicated satellite, then banking on a dubious privatization scheme that met no one’s goals. The one thing that has not taken place is realistic planning and budgeting to avoid breaking a flow of data that has chronicled three decades of change to the Earth’s land mass.
It’s still not too late, but the government is running out of cards to play.
Unfortunately, the administration’s latest Landsat data continuity strategy appears to be crossing its fingers and hoping that the already degraded Landsat 7 spacecraft, which was launched in 1999 with a five-year design life, will hang on until the first of a new series of weather satellites outfitted with land imagers is launched around 2010.
It might work, but clearly the driving force behind this gamble is a determination by the administration that Landsat data continuity is a nice thing to have, but not a budget priority.
Landsat 7 is hobbled by a sensor glitch that makes its imagery difficult to use for some applications and worthless for others. In addition, the plan for getting the replacement sensors into space by 2010 depends on incorporating the land remote sensing mission into the National Polar-orbiting Operational Environmental Satellite System (NPOESS), an effort that has technical and operational challenges that are not yet fully understood.
Now comes word that Landsat 7 has gyroscope issues that in the worst-case scenario could bring its mission to an end by 2007. The Landsat Data Gap Study Team, created this year to find alternatives to a dedicated satellite for keeping the land-observation data stream flowing, says there is a 90 percent probability that Landsat 7 will suffer a gyro failure in 2007. One of the satellite’s three gyroscopes already has been shut down for acting up, and the failure of another could prove fatal.
NASA and the U.S. Geological Survey are working on software to head off the gyro problem. Even if they are successful — which is by no means guaranteed — Landsat 7 still has a sensor that is literally on the blink, creating gaps in the available data.
The government is in this situation because of poor planning at best, indifference at worst.
The White House’s first gaffe was mandating that NASA and the U.S. Geological Survey transfer Landsat responsibility to industry. The Land Remote Sensing Policy Act of 1992 — which obligates the government to provide a follow-on to Landsat 7 — indicated a preference for a commercial mission, but it did not mandate one, and considerable evidence had piled up since that law’s passage that privatization was a dead-end path.
After spending two years and millions of dollars on the commercial Landsat Data Continuity Mission procurement, NASA got a single, unacceptable proposal from industry. Interestingly, the Land Remote Sensing Policy Act bars the government from trying out similar commercialization schemes with weather satellites.
Another option laid out in the law is internationalizing Landsat, and NASA raised that possibility following the collapse of the commercialization bid. Given that countries like France and India have strong land remote-sensing satellite programs that with some tweaking could provide Landsat-compatible data at a relatively low cost, internationalization seemed feasible. But for whatever reason, internationalizing Landsat never really got any traction.
The White House last year settled on a plan to add a Landsat-type imager to the NPOESS sensor suite, also an attractive idea because it would effectively make Landsat an operational rather than a research mission and in theory would cost less than launching dedicated satellites.
As an adjunct to that plan, NASA was to study the feasibility of a low-cost mission to avoid any data gap that otherwise might come between Landsat 7 and the first NPOESS satellite. Given the likelihood that NPOESS will be delayed — like most satellite programs — and the technical questions regarding its ability to accommodate the Landsat mission, procuring a dedicated gap-filler satellite was absolutely the right thing to do.
But the White House scrapped the gap-filler mission sometime late last year; or at least stood by while NASA pulled the trigger. With Landsat 7’s status more precarious than ever, a gap in the environmental-change data record is not so much a question of “if” as it is “when, and for how long.”
The White House still has a chance to reverse course and reinstate the gap-filler mission. That way it could at least minimize the data gap, especially in the event that incorporating land imaging into the NPOESS mission turns out to be more complicated than expected.
