[meteorite-list] NEAR Data Expected From Eros Surface

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:41:10 2004
Message-ID: <200102180243.SAA02790_at_zagami.jpl.nasa.gov>

http://www.space.com/missionlaunches/missions/near_radio_010216.html

NEAR Data Expected From Eros Surface
By Leonard David
space.com
16 February 2001

WASHINGTON -- This is broadcast station NEAR on your space dial. Stay tuned!

Sitting atop far flung Asteroid 433 Eros, NASA's Near Earth Asteroid
Rendezvous (NEAR) Shoemaker spacecraft is gathering science data for
transmission to Earth over the weekend.

Following a successful soft landing on the giant chunk of space flotsam, the
probe's first on-the-spot measurements using a Gamma Ray Spectrometer should
be received by ground stations on February 18.

That Gamma Ray instrument -- either resting above or in the asteroid's rock
and dirt covering -- is focused on a 4-inch (10-centimeter) circle of Eros.
An abundance of several important elements, such as potassium, silicon and
iron can be measured. Using gamma rays, the device detects specific elements
in the asteroid's surface.

Mission controllers at The Johns Hopkins University Applied Physics
Laboratory (APL) in Laurel, Maryland report that commands have been sent to
NEAR Shoemaker to start science operations on the asteroid's surface. APL
both designed and is managing the asteroid surveying craft for NASA.

Data is being collected by both the Gamma Ray Spectrometer, as well as an
onboard magnetometer.

To date, no magnetic field has been found at Eros. Discovery of an intrinsic
magnetic field at Eros would be the first definitive detection of magnetism
at an asteroid. The find would have important implications about the space
rock's thermal and geologic history.

Contact!

"We're pretty sure the spacecraft has received commands. There's been a
voltage drain, indicating the Gamma Ray instrument is doing what it needs to
do," said Helen Worth, an APL spokeswoman.

The relaying of science data from the asteroid to Earth is expected around
11:23 a.m. EST (16:23 GMT) Sunday. However, it is likely to take until early
Monday to ascertain whether data received is useful, Worth told SPACE.com.

NASA gave the go-ahead for engineers and scientists to remain in radio lock
with NEAR Shoemaker after the craft gently touched down on Eros February 12.

The mission was to conclude two days later. A surprise to many, the probe
remained intact and in good working order after coming to a stop on the
asteroid's rocky surface.

NASA extended the mission for up to 10 days. There is the possibility of a
further extension, to assure that enough listening time from ground stations
is found.

Following four-year a journey of more than 2 billion miles (3.2 billion
kilometers), and a yearlong observational campaign around Eros, NEAR
Shoemaker braked itself onto the asteroid, plopping down at less than 4
miles per hour (between 1.5 and 1.8 meters per second).

If the science data direct from the asteroid is received on Earth, it will
be almost five years to the day after being launched.

"We're in contact and delighted," said Robert Farquhar, NEAR mission
director at APL. "We expect to have all the data that we need by the end of
February," he told SPACE.com.

High science on low-gain

The car-sized spacecraft had already gleaned 10 times more data during its
circling of Eros than originally planned. It completed all the mission's
science goals before Monday's landing on the boulder-strewn mini-world.

Science data is being slowly transmitted through the spacecraft's low-gain
antenna, at just 10 bytes per second.

"We don't know if the instrument's still working," said Jacob Trombka, NEAR
team leader for the X-ray Gamma Ray Spectrometer at NASA's Goddard Space
Flight Center in Greenbelt, Maryland. "The detectors are very hardy. The
thing I'm more worried about is the wiring and all the electronic
connections," he said.

"We won't know if it's working until Sunday. We're looking forward to seeing
our first data right from the surface," Trombka told SPACE.com.

Trombka said the Gamma Ray device will take a period of time to stabilize
and provide the best and most reliable science information. The detector
itself is anywhere from in the dusty covering of Eros to sitting about a 3.3
feet (1 meter) above the surface. "It doesn't make much difference," he
said.

"Within seven days to 10 days we should have a good data set," Trombka said.
"If we get data, this is going to be an extremely good test of this sensor
for future missions, particularly for rovers on Mars," he said.
Received on Sat 17 Feb 2001 09:43:58 PM PST