Industry concerns that the U.S. government indecision about the future of the Landsat program will lead to a long gap in the delivery of low-resolution scientific remote sensing data escalated at the end of November when the aging Landsat 5 satellite suffered a potentially crippling malfunction.
Problems with a piece of equipment on the Landsat 5 satellite could mean the end of operations for the 21-year-old remote sensing spacecraft.
According to the U.S. Geological Survey, Landsat 5 started experiencing problems with its back-up solar-array drive Nov. 26. The drive ‘s function is to keep the solar panels pointed toward the Sun. When the drive’s rotation became sporadic, it prevented the solar panels from generating enough power to charge the satellite’s batteries.
“How it could get fixed is going to be the subject of much discussion with our engineers over the next few weeks,” Jay Feuquay, coordinator of the land remote sensing program at the U.S. Geological Survey, said in an interview Nov. 28. “We’re cautiously optimistic we will be able to resume some sort of operations, but we don’t know that for sure, and we don’t know how close to full operations we’d be able to get.”
It is possible Landsat 5 will still be able to operate for more limited use, but details on how that could happen are still unclear, according to Feuquay.
“We’ll have to work around whatever the onboard systems are,” he said. “It’s really whether or not the smart guys doing our engineering are going to be able to pull one more rabbit out of their hat.”
Landsat 5 already is operating on its back-up solar-array drive. Its primary array failed in January.
Feuquay said scientists should be able to determine what Landsat 5’s future is within the next two weeks or so. In the meantime, imaging operations have been suspended for the satellite.
Landsat 5, which launched in March 1984, originally was designed with a three-year shelf life, but has been operating beyond its expected capability until now. The government’s other remote sensing satellite, Landsat 7, has its own problems, as its main sensor malfunctioned in 2003, causing it to deliver degraded data since then.
White House policy officials are still deliberating the future direction of the Landsat program. A policy decision last year would have put a Landsat imager on the National Polar-orbiting Operational Environmental Satellite System (NPOESS), but problems with NPOESS have made that alternative less likely.
The White House Office of Science and Technology Policy (OSTP) is considering whether to launch a free-flying Landsat satellite in the meantime as an alternative and gap filler. OSTP spokesman Donald Tighe did not return calls seeking comment.
Feuquay said the U.S. Geological Survey still is waiting to hear from OSTP on their final decision. He confirmed a free-flyer mission is among the alternatives being weighed.
Industry representatives who rely on Landsat data have been lobbying government officials this month and expressing concern that additional delays in making a decision about the best way to go forward with the Landsat mission will result in a data-gap where no Landsat data is being collected for an extended period of time.
Kurt Allen, president of the Management Association for Private Photogrammetric Surveyors (MAPPS), and Karen Schuckman, president of the American Society of Photogrammetry and Remote Sensing (ASPRS), sent letters to OSTP and to NASA Administrator Mike Griffin advocating a free-flyer mission in light of the cost and technical problems plaguing NPOESS.
“We believe all other alternatives have been thoroughly explored at this point, and the only way to avoid a longer, and more devastating, data gap is to utilize the ‘bridge’ mission or ‘free-flyer’ mission strategy,” they stated in their Nov. 10 letter.
MAPPS, a lobbying group that represents the private-sector geospatial-mapping community, is concerned that something needs to be done about Landsat now, because while commercial providers can provide high-resolution imagery to those who need it, there is little or no opportunity to get the kind of data Landsat provides elsewhere.
“Low-resolution imagery is not something the private sector is really in the market for producing,” Allen said in an interview.
A data gap already is happening, according to Samuel Goward, a geography professor at the University of Maryland in College Park who co-chairs the National Satellite Land Remote Sensing Data Archive Advisory Committee. The committee also sent a letter to the Department of the Interior Nov. 18 urging quick action.
“First we waited a series of years trying to do a data buy,” Goward said, referring to the fact that the U.S. government investigated the possibility of purchasing imagery from commercial providers. “Now we’ve wasted another series of years trying to go on NPOESS. Depending on who you talk to, it could take up to five years to get a procurement out the door and get a system into orbit. If we had a total failure today, we’d have at least a five-year gap, and probably longer than that. We could be looking at the better part of a decade before we get out of all this.”
Goward said he believes the government should consider adopting a small satellite approach rather than a large, free-flying satellite mission, and that technology emerging in Europe could allow this to happen as quickly as procurement of a free flyer would take, but at a lower cost.
“The real advantage to that would be the cost structure. With the current stresses on our federal budget, it would make it a lot more doable to accomplish incrementally than a traditional free-flyer,” Goward said.
Whether Landsat 5’s latest problems will speed a decision from the White House remains unclear.
“It certainly adds to the urgency that was already there,” Feuquay said. “It’s kind of difficult to say whether the fact that a 21-year-old satellite having problems makes things any more urgent. That situation was urgent 18 years ago. But it’s unfortunate given the current situation.”