Next week, data-collecting sessions by the DSN are slated for Feb. 26 and Feb. 28.
"Well get DSN tracks this coming Monday and Wednesday, and thatll be it," said Robert Farquhar, NEAR mission director at The Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland.
APL built and is managing the NEAR Shoemaker mission for NASA. The DSN is operated for NASA by the Jet Propulsion Laboratory in Pasadena, California.
"We basically got a 14-day extension of the mission" from NASA, Farquhar said. "This is the end. Its time to shut it down," he said.
Eros misidentified?
By obtaining more DSN time, a gamma ray device on the probe should be able to return a more complete data set, said Jacob Trombka, team leader for NEAR Shoemakers X-ray/
instrument at NASAs Goddard Space Flight Center in Greenbelt, Maryland."After everything has been adjusted, were starting to see the signals from the instrument that weve been wanting. Its looking very good," Trombka told SPACE.com. "Who would have thought of this?" he said.
What the NEAR Shoemaker data might be saying is that Eros may have been mis-classified by scientists, Trombka said. Eros has been previously identified as an S-type asteroid, composed of metallic iron mixed with iron and magnesium silicates.
"You always have to have a few mysteries. Its trying to tell us something. Weve got to learn how to listen," said Trombka.
"If it was all obvious, we would not have gone there. Its going to take a lot of sweat, maybe over the rest of the year" to sort through all the data, Trombka said.
Magnetic mystery
Joining Trombka in pondering exactly what Eros is telling scientists is Mario Acuna, the science team leader for the magnetometer at Goddard.
The magnetometer, now switched off, operated for three days on the asteroids surface.
"This is a very non-magnetic object. And thats where the real head scratching comes in. We look at the meteorites, which are supposedly related to asteroids. But each time we look, we see all these differences. This is a different body all together. Thats where the fundamental issues are: How can a body like this be so non-magnetic?" Acuna told SPACE.com.
Acuna said that having additional magnetometer data would be ideal. But turning the instrument on is more a resource issue than a hardware issue.
"We are pretty strapped to the wall with respect to resources and trading off against other science objectives. Its a question of science versus resources," Acuna said.
Eros has turned out to be a body with very low residual magnetism, Acuna said.
"As usual, things are not what you expect. We expected a body with a fairly strong magnetic field based on inferences from other asteroids. All its telling us is that our assumptions were wrong. Weve got to go back and rewrite the book essentially. But thats the nature of science. Thats exactly how we move forward -- by being surprised each time we look somewhere," Acuna said.
DSN radio play
Getting the extra time from the Deep Space Network has been going fairly smoothly, said Gary Moore, DSN telecommunications planner at APL.
The radio link between Earth and NEAR Shoemaker has been via the DSN tracking dish at Goldstone, California, Moore said. "Its been a very pleasant surprise that we actually had enough signal to work with to get data back on Earth," he said.
But the time for listening to NEAR Shoemaker closes off next week.
"Weve achieved our objectives at that point. If we get the data down, it should be very good data," Moore said. "Weve been very fortunate and its been a big boost to the science of the mission that we are able to get data down from the surface," he said.
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