Greg Myers
					Borehole Research Group
					Lamont-Doherty Earth Obervatory
					Columbia University

	Beginning with Leg 166, LDEO has routinely utilized high speed
satellite equipment to transmit log data from the JOIDES Resolution to
shorebased processing centers. Transmitting log data for rapid
processing has proven highly successful in enhancing the accuracy of
shipboard log data analysis, reporting and increased data quality
control. The data including Triple combo, FMS/Sonic, VSP and
Geochemical log data are corrected for depth, borehole condition and
environmental effects then returned to the ship for use by the
shipboard scientists. The data are routinely turned around in a five
to six day period.  This inear real timei response has been
facilitated through the deployment of VSAT (very small aperture
terminal) satellite equipment capable of realized transmission rates
up to 180Kbps or 180,000 baud. VSAT equipment has been leased from
Schlumberger Offshore on a per month trial basis with special testing
requirements. Because of the incipient nature of the stabilization
technology, certain prototypical VSAT components were not fully tested
in a heaving maritime environment prior to deployment. Therefore, as
part of our leasing arrangement with Schlumberger, LDEO provides a
platform from which test the unit and ultimately generate feedback
relating to the systems performance and reliability. Since its
installation on Leg 166, the unit has provided not only a stable data
link to our shorebased processing centers but also stable voice, fax
and world wide web browsing capabilities.

	VSAT equipment consists of a stabilized antennae mount and
antennae currently resident on the helipad. Below deck equipment is
integrated into the Maxis 500 data acquisition system making
installation and operation extremely simple. Two antennae dishes and
radios are available as the ship moves between various satellite
coverage regions. A 1.2 meter satellite dish is utilized when in the
Ku band foot print, typically located within 100 miles of the
continental United States. When out of the Ku Band foot print, a
larger 2.4 meter dish and more powerful radio are installed to capture
the less focused energy of the C-Band thus extending the effective
coverage area of the system. Presently, the VSAT system coverage
regions include the waters adjacent to North America and the majority
of the Atlantic including Africa. Satellite coverage, however, is not
available in important ocean regions where drilling operations are
scheduled over the next several years.

	Limitations of the VSAT system including coverage areas,
excessive antennae size and prototypical equipment approaching the end
of its service life with no spares parts or service, has warranted the
investigation of other high speed data transmission alternatives. An
attractive option currently under consideration is an Inmarsat B
terminal capable of data transmission rates up to 56 K/bs or 56K
baud. High speed data, voice and fax capabilities are all standard
options with Inmarsat B units purchased off the shelf. Satellite
coverage areas and technical support are global except in the regions
above 70 degrees north and 70 degrees south latitude. To determine the
suitability of an Inmarsat B system for the wireline logging
operations aboard the JOIDES Resolution, LDEO has made a unit
manufactured by ABB Nera available for testing during Legs 170, 171A
and 171B. All hardware and software of the borrowed unit were
installed in San Diego prior the beginning of Leg 170. The
installation was a joint effort between LDEO, Woods Hole Oceanographic
Institution, TAMU and SEDCO. Antennae and below deck equipment
locations were determined jointly with the antennae being mounted on
top of the DP shack and all below deck equipment mounted in the radio
room. Prior to the shipis departure, the system was thoroughly tested
to insure trouble free operation for the upcoming legs. The unit is
presently undergoing a period of intense evaluation.

	Until Recently, LDEO has been engaging in high speed satellite
communications apart from SEDCO and TAMU. As the VSAT testing comes to
a close LDEO is wasting no time in exploring other options with its
ODP partners. A joint satellite communication arrangement between,
TAMU, SEDCO and LDEO is the ultimate goal of the present Inmarsat B
testing initiative. Now, as the shipboard Inmarsat B system is proving
its ability to send log data quickly and inexpensively, it is clear
that both SEDCO and TAMU are likely to benefit from the systemis great
flexibility and cost effectiveness for sending email and other large
data sets.  Testing by both SEDCO and TAMU has been greatly encouraged
during the four month period of evaluation so that all involved
parties will be in position to provide input when deciding what system
would be best suited for the Ocean Drilling Program as a whole.