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OCR for page 77
4
Addressing the Need for Improved
Deep Submergence Assets
HIGHLIGHTS
This chapter
· Explores options for providing better capabilities over greater
geographic range (to support call for new ROV)
· Explores options for upgrading individual components (to
support calls for a super-ROV and an enhanced HOV)
· Explores options for improving the overall capability of the
asset pool (e.g., standard tool i nterfaces)
Research conducted in the ocean depths has important implications
not only for understanding the oceans, but also for advancing some of the
most basic and profound areas of human inquiry. In recognition of the
significant potential this research holds and the unique and challenging
requirements that work in the deep ocean represents, the National Sci-
ence Foundation (NSF), National Oceanic and Atmospheric Administra-
tion (NOAA), and U.S. Navy have made a significant commitment to pro-
vide operational support for these efforts. Maximizing the return on the
investment made in this unique and challenging scientific effort will re-
quire overcoming a number of natural and unique human obstacles. Yet,
pursuit of many high-priority science goals will be limited by both the
current capabilities and the current capacity of National Deep Submer-
77
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78
FUTURE NEEDS IN DEEP SUBMERGENCE SCIENCE
gence Facility (NDSF) assets. Continued expansion and diversification of
the pool of potential users can be accommodated only by expanding ac-
cess to needed assets. As is often the case, solutions to one set of problems
may exacerbate others; thus, this chapter attempts to explore the various
obstacles and their potential solutions in a holistic manner.
IMPROVED UTILIZATION OF EXISTING ASSETS
As discussed in Chapter 3 it appears that the scientific demand for
deep submergence assets is, at present, not being adequately met. Part of
this problem can be traced to an inadequacy in the number and capabili-
ties of existing assets. Another part, however, can be attributed to the way
in which existing assets are utilized. In particular, the current system does
not always ensure a match between the requirements of federally funded
projects and the appropriate deep submergence assets.
Modification of existing assets and construction of new assets to alle-
viate this problem would represent both a significant capital investment
and an additional demand for operating funds. Decisions to commit these
resources should be accompanied by a commitment to ensure the best use
of the nation's deep submergence assets. The management of the nation's
deep submergence assets should, therefore, be clarified and revised to
ensure the optimal use of both existing and potential assets in future sci-
entific research.
A Question of Access
Many previous studies have called for some reexamination of the
use of U.S. and foreign platforms to support deep submergence science.
However, detailed guidance beyond general calls for "increased access"
have not been put forward. Thus, some additional discussion is war-
ranted here.
As previously discussed, NDSF currently operates two vehicles: the
HOV (human-occupied vehicle) Alvin and the ROV (remotely operated
vehicle) fason II. Support for the operation of these vehicles is guaran-
teed by the three NDSF sponsoring agencies (NSF, NOAA, and the
Navy). The agencies are also major supporters of research that utilizes
NDSF assets. For example, in 2002, NSF and NOAA accounted for nearly
100 percent of the operational days of all NDSF platforms, with NSF
generally accounting for more than 70 to 80 percent annually. This ar-
rangement ensures consistent support for NDSF, while allowing some
flexibility in the burden borne by each of the three sponsoring agencies.
This, in turn, allows each agency to predict its annual contribution to
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ADDRESSING THE NEED FOR IMPROVED DEEP SUBMERGENCE ASSETS 79
NDSF funding and to develop budget mechanisms to accommodate that
contribution.
The use of NDSF assets and University-National Oceanographic Labo-
ratory System (UNOLS) vessels as surface support ships by scientists
funded through NSF is covered by the funds from the Marine Operations
Section of the NSF Division of Ocean Sciences (OCE). Proposals to NSF
requesting the use of these vehicles are submitted to a number of science
programs within OCE. No costs for the use of NDSF or other UNOLS
platforms are included in the budgets of these individual proposals. This
policy helps the evaluation process focus on the intrinsic scientific merit
of proposals that may require deep submergence assets; it also ensures
that assets that are already funded are utilized to the fullest extent pos-
sible. For the most part, vehicle use is essentially guaranteed to any project
that is funded by the science program to which it was submitted. Schedul-
ing vehicle use is facilitated in at least two ways. First, projects may be
postponed to accommodate vehicle schedules. Second, one vehicle may
be substituted for the other in projects where such substitution is possible.
In some cases, it is simply not possible to accommodate vehicle require-
ments, and proposals may be rejected or deferred on these grounds.
Conversely, proposals to NSF that request the use of non-NDSF plat-
forms must include platform operating costs in the proposal budget.
Should the proposal be funded, funding for platform use must be pro-
vided by the science program to which the proposal was submitted. Since
the additional cost for the use of these platforms (not including the cost of
support ships) can be substantial ($10,000 to $30,000 per day of use), this
additional cost is widely perceived as placing such proposals at an unfair
disadvantage compared to those requesting NDSF platforms. Even when
NDSF assets are available, a suitable UNOLS support ship may not be. In
such instances the costs on non-UNOLS vessels may represent as much as
one-third of the cost of project (RIDGE 2000, 2003~. Under the current sys-
tem, this additional cost must again be borne by the science program. The
additional cost to the scientific programs of using non-NDSF or other non-
UNOLS platforms is perceived by the scientific community as placing pro-
posals calling for their use at a significant and unfair disadvantage. To the
degree that this perception discourages scientists from more fully devel-
oping high-quality research programs that cannot be supported by the
existing pool of NDSF assets, this lack of access to suitable assets is limit-
ing the scope of deep submergence science (UNOLS, 1999~. Steps should
be taken to eliminate this effect if a meaningful expansion of deep sub-
mergence science is to be realized. Given that any action to develop addi-
tional NDSF assets will take at least two years, mechanisms for allowing
limited access to non-NDSF (and other non-UNOLS) platforms should be
explored.
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FUTURE NEEDS IN DEEP SUBMERGENCE SCIENCE
Understanding the NDSF Cost Structure
Because the NDSF is funded irrespective of vehicle use, the marginal
cost (i.e., the cost of an additional day of operation) is zero. In contrast,
the marginal cost of the use of non-NDSF assets can be substantial. From
a fiscal perspective it is therefore sensible to require, when possible, that
NDSF assets be used in favor of non-NDSF assets. In the absence of addi-
tional funds, excess demand for NDSF assets can be managed by a combi-
nation of asset substitution, scheduling, and if necessary, proposal rejec-
tion. If additional funds are available, excess demand can also be
addressed by leasing non-NDSF assets.
There appear to be situations, however, in which deep submergence
scientific goals cannot be met by NDSF assets but can be met by non-NDSF
assets. Moreover, these limitations preferentially restrict the use of NDSF
assets in certain areas of deep submergence science. For example, limita-
tions on the viewing capability of Alvin and on its ability to achieve neutral
buoyancy at multiple depths during a single dive make it less suited for
certain types of midwater research than certain non-NDSF assets. In addi-
tion, the strong pressure to revisit specific sites on an annual or biannual
basis, termed the "yo-yo" effect because Atlantis and Alvin have been pulled
back and forth through the Panama Canal to and from these sites, limits
access to Alvin in other geographical locations. For this reason, the valid
fiscal argument favoring the use of NDSF assets has the unintended conse-
quence of restricting the scope of deep submergence science.
In theory, one possible solution to this problem is to abolish the NDSF,
sell its assets, and essentially create a free market for deep submergence
scientific support. This solution, however, fails to capture the true econo-
mies of scale in the operation of deep submergence assets. On the oppo-
site extreme, a solution would be to expand NDSF to cover funding for
any deep submergence asset. This approach could reasonably be expected
to increase overall costs dramatically, because all assets would become
fixed-cost assets regardless of demand. A more reasonable solution that
expands the scope of deep submergence science while capturing econo-
mies of scale is to upgrade the capabilities of the NDSF assets so that they
can be used in all areas of deep submergence science. Although this is
clearly an important part of the solution, by itself it may be inadequate.
First, these upgrades, if they occur, will not be completed for two to three
years, and some short-term measures are needed. Perhaps more impor-
iThis, of course, assumes that all crew are salaried (no overtime) and there are no expend-
ables. Even for instances in which this assumption is invalid, the marginal cost is still mini-
mal when compared to the additional cost (beyond the fixed cost of maintaining NDSF
equipment) of leasing equipment outside.
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ADDRESSING THE NEED FOR IMPROVED DEEP SUBMERGENCE ASSETS 81
tartly, there is a danger that the existing pattern of use of NDSF assets
will simply persist. One way to address both of these problems is to pro-
vide modest but immediate funding to support the use of non-NDSF as-
sets. This funding might, but need not, reside within the NDSF, but to
avoid disparate treatment, it should not be included in the budgets of the
NSF/OCE scientific program. An additional benefit of establishing such a
fund is that it would serve as a gauge of demand for capabilities not pro-
vided by current NDSF assets. NSF/OCE should establish a small pool of
funds (on the order of 10 percent of the annual budget for NDSF) that
could be targeted specifically to support the use of non-NDSF vehicles for
high-quality, funded research when legitimate barriers to the use of NDSF
assets can be demonstrated. If, as additional assets become available, the
demand for non-NDSF vehicles declines (or never materializes), these
funds could be used to address other (non-deep submergence) marine
operational needs as determined by NSF/OCE.
DEVELOPING NEW ASSETS
Improved utilization of existing assets, although an important step,
cannot be expected to fully address the scientific demand. As is apparent
from Chapters 2 and 3, there is a need for different platforms to carry out
different missions. Given the range of capabilities needed, this study con-
cludes that the addition or enhancement to two specific platforms would
most benefit science: a deepwater ROV system and an improved HOV.
These platforms offer the most science for the current technology and,
when used in conjunction with other platforms such as deep towed ar-
rays, autonomous underwater vehicles (AUVs), ROVs, and other
submersibles, provide tremendous wide-scale and localized-scale effi-
ciency for performing scientific research. The addition of these assets
would provide the greatest opportunity to meet the demands of world-
class deep submergence science for scientific endeavors in all regions of
the world and in more than 98 percent of the ocean's volume.
Construction of a New (7,000-m) ROV Platform
The present pattern of use (see Table 3-1) of existing scientific ROVs
suggests that the greater geographic flexibility for ROVs comes when they
can be operated in a "fly away" manner. Fly-away refers to an ROV that is
not tied to a specific mother ship and can be relocated to a suitable ship of
opportunity, making it an attractive tool for scientific research in various
and diverse areas of the globe. As the portfolio of deep submergence stud-
ies diversifies in response to greater demand to conduct funded research
in various regions of the world, additional demand for an already fully
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FUTURE NEEDS IN DEEP SUBMERGENCE SCIENCE
subscribed Jason II can be expected. As discussed in Chapter 3, NSF's
Ocean Observatories Initiative (OOI) will provide a significant new capa-
bility to support deep ocean science and can be expected to have a signifi-
cant impact on UNOLS fleet and deep submergence assets (NRC, 2003a).
Although the placement of fixed observatories will relieve some demand
for NDSF assets to support time-series studies, it does not appear likely
that Jason II or Alvin will be undersubscribed in the near future. Further-
more, the demands for ROVs to support the construction and mainte-
nance of the OOI network and the scientific programs associated with it
will be significant. Assets specifically dedicated to support observatory
science cannot be assumed to be available to also support expeditionary
science. The NRC (2003a, p. 8) report concluded:
Without a commitment from NSF to augment ship and ROV capabilities to
meet these needs, the scope and success of the ocean observatory program could
be jeopardized and other types of ocean research requiring these assets could be
negatively affected. UNOLS and its Deep Submergence Science Committee
(DESSC) should develop a strategic plan that identifies the most cost-effective
options for supplying the required ship and ROV assess for observatory opera-
tion and maintenance and NSF should commit the necessary funds to acquire
these assets.
Recommendations made in this report are exclusive of and in addi-
tion to those made for support of the OOI.
Characteristics of an Improved ROV System
Several factors should be considered when developing a new ROV
system to support expeditionary science. Probably most important over-
all is that the new asset be considered as an overall system rather than
simply as a new ROV. Such an approach supports the incorporation of
several attributes that will greatly enhance its utility as well as its ability
to complement existing assets. Some of the most significant attributes in-
clude standardized tooling suites, open software and hardware architec-
tures, electric thruster systems, a variable ballast system, tether manage-
ment systems, improved handling systems, and camera and lighting
systems.
Standardized Tooling Suite. Interchange of tools, sensors, and equipment
will be greatly enhanced by adopting standard interfaces between plat-
forms. International standards such as those of the International Organi-
zation for Standards, American Petroleum Institute, and others should be
agreed upon by the community and systems designed (or retrofitted) with
standardized interfaces as a design parameter. Standard tools should be
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ADDRESSING THE NEED FOR IMPROVED DEEP SUBMERGENCE ASSETS 83
built to accommodate interchangeability and use with both ROV and HOV
platforms. It is recognized that there will be special tools for specific one-
time science missions, but standardization of interfaces will save design
time, setup time, and operations and hence allow more time and resources
to be devoted to research.
Open Software and Hardware Architecture. Open software architectures that
incorporate object-oriented application modules will support faster and
cheaper development, module reuse, shorter validation and verification
efforts, and reduced maintenance costs over the life of the program. Use
of commercial off-the-shelf (COTS) software for major infrastructure items
(e.g., operating system, networking protocol) will let specialized onboard
and offboard software systems take advantage of significant COTS soft-
ware investments and advances. Open hardware architectures that follow
commercial standards will likewise benefit from COTS product improve-
ments while minimizing the impact of vendor volatility as long as atten-
tion is paid to the development of an adequate "middleware" layer that
serves to isolate software applications from hardware components. De-
sign and deployment of open architectures will require significant effort,
but the benefits extend beyond single platform development. Benefits may
extend not only across vehicles, but also across classes of vehicles (i.e.,
HOVs, ROVs, AUVs) and locales (i.e., both on the vehicle and at the mis-
sion management stations).
Greater Horsepower. This would be required to make the ROV more ca-
pable at depth for station keeping and moving into position. Providing
greater horsepower to the ROV allows for more powerful thrusters for
overcoming current and drag from the tether or umbilical cables as well
as additional capacity for running tools, sensors, lights, hydraulic power
units, video, and so on.
Electric Thruster System. An electric thruster system allows the ROV to be
unobtrusive during operation. The Monterey Bay Aquarium Research
Institute's (MBARI's) Tiburon ROV, which has all-electric thrusters with a
hydraulic power pack for the operation of the arms and tooling skids, is
an excellent example of this technology. Existing commercial electric sys-
tems are also available (e.g., the Quest ROV system from Alstom). These
systems excel throughout the water column, whereas hydraulic systems
tend to overheat at shallower depths.
Variable Ballast Systems. To perform midwater research and delicate stud-
ies just above a mudline on the seafloor and in boundary layers, a variable
ballast system would be required. Such a system ensures greater visibility
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FUTURE NEEDS IN DEEP SUBMERGENCE SCIENCE
and more efficient use of dive time by allowing the submersible to trim at
specific depths without the use of thrusters. This minimizes sediment and
flow field disturbances and enables fine manipulation of fragile equip-
ment, samples, and experiments even along a rough seafloor. The ability
to maintain a stable altitude in the water column without thrusters and
adjusting the speed of forward movement relative to suspended particles
allow sinking particles to be followed through the water column. Sedi-
mentation rates and study of the changes in chemical microenvironments
around and within such particles can thus be measured along with sam-
pling of the particles. The ability to float within any given water mass,
moving in exactly the same speed and direction as the water mass itself,
also gives "stealth" capabilities in the bioluminescent minefield that com-
prises the midwater environment. This is imperative for studies of biolu-
minescence and the effect of light on the ecology of the midwater realm.
Measurements relating to fine-scale physical processes such as mixing
vortices and interface structure and dynamics can be done from a stable
platform through advanced dye injection techniques and accurate apprais-
als of the fine-scale distribution of plankton and other particles in the
water column or benthic boundary layer. The mapping of vertically strati-
fied fine-scale structures in the water column along a horizontal plane
and measurements of associated chemical and biological variables can also
be done only when a variable ballast system is employed.
Tether Management System (TMS). This hardware augments the variable
ballast system and allows the system to be relocated to different ships,
thereby alleviating the need for heave compensation of the power cable.
A TMS with extended (long) tethers allows the ROV to "decouple" from
the heavy and stiff armored umbilical and attenuates the effect of surface
vessel induced reactions. A long (500 to 1,000m) neutrally buoyant, small-
diameter tether reduces the drag on the ROV, allowing excursions further
from the "footprint" of the surface vessel, and reduces the influence of the
TMS for midwater- or seafloor-based work. This allows the ROV to reach
large survey or exploration areas without repositioning the surface sup-
port vessel or requiring dynamic positioning capabilities. Docking the
ROV to the TMS during launch and recovery allows for safer operations
and expands the sea state window for launch and recovery.
Improved Handling Systems. Launch and recovery of the ROV are two of
the most critical aspects of operations. Careful design of the handling sys-
tems will enable safer operations by reducing the dangers to personnel
and equipment while providing the ability to operate in higher sea states.
The system should be designed to deploy the ROV overboard with a mini-
mum number of personnel. It should allow for "latching" the ROV-TMS
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ADDRESSING THE NEED FOR IMPROVED DEEP SUBMERGENCE ASSETS 85
to the launch system during launch and recovery operations to reduce
movement of the ROV-TMS. When operating in harsh environmental con-
ditions, consideration should be given to a "cursor" system on the sup-
port vessel. A cursor system is a rail-type system that allows the ROV to
be deployed in heavy seas in a controlled manner. The ROV is controlled
and guided to a position below the sea surface where it may then be de-
ployed with less interference from the motion of the sea.
Improved Camera and Lighting Systems. Visualization of the ROY's environ-
ment is fundamental. High-definition (HD) cameras and associated
lighting systems are essential pieces of equipment. A wide-angle or side-
lighting illumination and highly light-sensitive cameras are needed for
viewing the fine internal structures of gelatinous animals and large par-
ticle aggregates. The use of HD cameras will provide operators, observ-
ers, and researchers, via onboard and real-time satellite transmission,
with greater definition of objects and the areas being viewed. Documen-
tation will be enhanced, and imagery suitable for education and public
outreach will also benefit. Multiple camera systems with overlapping
fields of view to give real-time panoramic displays of the water column
or ocean floor should also be incorporated to increase search efficiency
and imaging capabilities.
Multiple-Frequency Sonar for Biological Studies. Recent developments in
acoustic identification of marine life suggest that consideration be given
to incorporating more sophisticated sonar systems into ROVs (and HOVs)
intended to support midwater column work. Acoustic backscatter nor-
mally removed during signal processing of data collected for seafloor
mapping can actually yield insights into the distribution of marine bio-
mass in the water column. Furthermore, a fairly large database of species-
specific acoustic signatures is being developed for many finfish species.
Such techniques could greatly enhance the capabilities of ROVs conduct-
ing biological transects or other midwater column biological research.
These systems may also have utility for mapping both diffuse and plume
effluent from seeps and hydrothermal vents.
Use of Seven-function Arms. A seven-function spatially correspondent (SC)
manipulator plus a "grabber" manipulator allows experienced as well as
inexperienced scientists to control experiments that require a delicate
touch. The use of seven-function SC manipulators (the commercial indus-
try standard) will increase the ability of operators to perform precise tasks
with a minimum of effort and in less time. The use of a second heavy
grabber manipulator for placing large science packages, taking large
samples, or moving objects should be considered.
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FUTURE NEEDS IN DEEP SUBMERGENCE SCIENCE
External Data Links. The ability to "plug and play" new tools and to re-
place components quickly without breaking a pressure boundary allows
external experimental apparatus to be plugged into the ROV electronics
system without opening up the main electronics can. This is greatly facili-
tated by the use of an external data link housing and saves hours in set up
and de-mobilize time.
Improved Reliability. Reliability of commercial ROVs has improved dra-
matically over the years. Some of the design and operating philosophy
used by the commercial industry should be considered in any new design
or refurbishment of science ROVs. For example, the use wherever pos-
sible of standard "off-the-shelf" equipment such as lights, cameras, ma-
nipulators, thrusters, winches, hydraulic actuators, connectors, comput-
ers, and instruments will increase the reliability of the ROV system and
facilitate procurement of spare parts. Training of operators and techni-
cians is paramount for improved reliability, as are operating and mainte-
nance manuals, regular maintenance schedules, and adequate onboard
spare parts.
The recommended details for this 7,000m ROV platform come from a
wide body of work presented to the committee, found in the literature, or
currently in use on scientific and commercial systems. Most are readily
available off the shelf as components. The total cost of the system would
be approximately $5 million, and it could be built and ready for service
within one year of authorization.
Using the current UNOLS model, this ROV system could be mobi-
lized to the current fleet without any significant additions of hardware,
and the operational requirements would be similar to those for the cur-
rent Jason II crew. Construction of a new ROV would not only address the
current excess demand for Jason II but also significantly enhance the geo-
graphic range over which deep submergence science can be carried out.
Although this study did not have the time or resources to explore the cost
and benefits of operating the NDSF asset pool as a distributed facility,
serious consideration should be given to basing any new ROV at a second
location. Although there may be additional costs involved in having a
second facility, such an arrangement could offer greater flexibility in
cruise scheduling while minimizing any transit time required for periodic
overhaul and refit.
Developing a More Capable HOV
In 1999, the deep submergence scientific community responded to a
questionnaire circulated by Woods Hole Oceanographic Institution
(WHOI) on improved submersible capabilities. Based on these results,
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ADDRESSING THE NEED FOR IMPROVED DEEP SUBMERGENCE ASSETS 87
WHOI developed some preliminary specifications for an improved HOV
(R. Brown, Woods Hole Oceanographic Institution, Woods Hole, Mass.,
written communication, 2003~:
· Ascent or descent in two hours to 6,000m
· Improved viewport arrangement
· Increased sphere volume
· 4000-pound (in water) external science payload
· Battery capacity increase of 30 percent
· Automated position keeping in all axes
· Enhanced controls and monitoring for single-pilot control
· Pan and tilt video for each observer
Based on the preliminary requirements developed by WHOI, and aug-
mented by input received during the course of this study, it is clear that
additional improvements should be pursued in the following subsystems:
(1) development of a mercury-free trim system due to environmental con-
cerns; (2) complementary electronics and tooling fixtures that match with
new 7,000m ROVs this is critical for a cross-platform continuity of ex-
periments; (3) optional fiber-optic cable to allow expanded communica-
tion with the surface for certain applications (e.g., video feed to other sci-
entists, navigation data, surface control of cameras and equipment); (4)
target localization, fixation, and following by tracking eye movements for
video cameras onboard; and (5) a robust variable ballast system.
Based on discussions with scientists primarily interested in the sea-
floor, WHOI explored three options for developing an enhanced HOV.
Since these were used as a starting point for consideration during this
study, they are discussed here. In their simplest form they include the
following:
· Option 1: An improved 4,500m Alvin using Seacliff or components
of Seacliff
· Option 2: A 6,000m Alvin using the Lokomo hull
· Option 3: A new HOV (referred to as Alvin II in the WHOI report)
A summary of these three options as described by WHOI is presented
in Table 3-2. There are a host of variations on these three options with cost
estimates ranging from less than $1 million for a minor modification to
$13 million for a completely new Alvin. The Committee on Future Needs
in Deep Submergence Science has reviewed these options and discussed
additional variations that were not included in the WHOI reports (Table
4-1~. The committee also considered the feasibility of a full-ocean-depth
HOV. It was determined that an 11,000m HOV was not a feasible option
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FUTURE NEEDS IN DEEP SUBMERGENCE SCIENCE
believed that modification of the existing Alvin (Option 2) would not pro-
vide the best science capability for the cost, compared to a new HOV that
uses the existing Alvin sphere.
In the long run, fabricating a new titanium sphere may be high
risk, but represents less overall risk since the existing Alvin sphere
would not be destroyed. In addition, the deep submergence engineer-
ing community would have obtained valuable experience in fabricat-
ing the new titanium sphere, whether it is successful or not. The most
promising approaches for moving ahead during the time frame articu-
lated by NSF/OCE would make use of one of the two existing spheres.
The first is the third, unused sphere from the Russian Mir HOV series
(referred to as the Lokomo sphere), which has been rated to 6,000m
and has a better configuration of portholes allowing both an expanded
field of view and the maximum diameter of the sphere to be used for
human occupancy thereby somewhat relieving the cramped condi-
tions within the sphere. Given the lack of a clear and overwhelming
scientific argument for conducting HOV operations at depths greater
than 4,500m, it is not obvious that significant resources (in excess of
those needed to fully upgrade the current Alvin) should be expended
(i.e., although a deeper-diving HOV would be considered highly de-
sirable, it is not clear that it would be essential). However, viewing
and internal space configurations would benefit. Thus, constructing
an HOV capable of operating at significantly greater depths (6,000m
plus) should be undertaken only if additional design studies demon-
strate that this capability can be delivered for a relatively small in-
crease in cost and risk.
Innovative Technological Advances
Given a major investment in new assets, innovative technological
advances should be incorporated into new HOVs, ROVs, and AUVs
whenever practical to support current and future research needs of the
scientific community. Enhancements (e.g., better cameras, lights, commu-
nications, computational platforms, tool pools) should be made to expand
the platforms capabilities and useful lifetime, reducing the pressure to
build new systems in the near future. A number of promising technolo-
gies for future ocean science needs have been identified based on recom-
mendations in the following reports: UNOLS (1994, 1999) and NRC (1996,
2003a). They are discussed later, but first these reports are incorporated
into the overall context of mission management since this drives the basic
functional requirements, which in turn drive technology development and
application efforts.
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ADDRESSING THE NEED FOR IMPROVED DEEP SUBMERGENCE ASSETS 95
Mission Management
Much of HOV mission management is done manually once the initial
pre-mission planning is completed. ROVs and AUVs, however, can be
operated along a spectrum, ranging from manual tale-operation, to moder-
ate levels of automation, to high levels of autonomy. Tele-operation places
the operator "in" the loop, relying on onboard sensors to assist in posi-
tioning, rather than viewing the vehicle's position directly via a viewport.
With moderate levels of automation (e.g., an autopilot), the required con-
trol bandwidth is reduced and the operator is less intensively engaged in
inner loop control. With higher levels of automation (e.g., waypoint naviga-
tion open-loop raster scan area search behaviors) operator engagement is
sporadic monitoring overall mission progress and setting high-level
platform goals or behaviors in a supervisory control mode of interaction
(Sheridan, 2002~. Being "in" the loop, the operator can step in when or if
the onboard levels of automation cannot deal with a wide range of contin-
gencies (e.g., an unanticipated subsystem failure) to override the vehicle
automation and/or reconfigure the system to ensure mission success or,
at least, vehicle recovery. Dealing with a broad range of contingencies-
unanticipated and/or without "response scripts" requires a level of
onboard intelligent behavior that is labeled autonomy: situational aware-
ness, engagement in (some) reasoning under uncertainty, and decision
making (to generate plans) with extremely limited or no operator inter-
vention. Platform autonomy puts the operator effectively "out of" the
loop.
Technological advances, some of which are described below, estab-
lish the level of automation along a spectrum, but of equal importance are
issues concerning the manner in which the operator interacts with the
system, independent of the level of autonomy. As identified in a recent
U.S. Air Force study on unoccupied aerial vehicles, this area of human-
system integration is not merely about the operator controls and displays
(the human-computer interface, or MCI), but also about the functional in-
teractions between the human and the system performing the operations
(U.S. Air Force Scientific Advisory Board, 2003~. At low levels of automa-
tion (high levels of tale-operation), the display demands become paramount:
maintaining operator awareness particularly spatial awareness re-
quires high levels of sensory fidelity (e.g., resolution, field of view, depth
of view, illumination, color), with high demands on onboard sensors,
transmission bandwidth and latency, and displays made available to the
operator. These effectively "max out" when demands are made for virtual
tale-presence; that is, a perceptual sensation indistinguishable from direct
observation. Control demands are probably maximal as well since fast con-
trol loops have to be maintained, but these are minimal demands when
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96
FUTURE NEEDS IN DEEP SUBMERGENCE SCIENCE
compared with the imaging sensor and download requirements. Func-
tional demands are all minimized in terms of what the vehicle has to pro-
vide, since the operator is doing most of the work. This, of course, results
in maximum operator workload. With high levels of platform autonomy
at the opposite end of the spectrum, operator display or control demands
(and communications requirements) are minimal. Functional demands for
the operator are low, but this comes at the expense of extremely sophisti-
cated software architectures and algorithms underlying "intelligent vehicle
behaviors." On the basis of the previously cited Air Force study, much of
this functionality is still years away, even in the R&D arena. In the middle
of the spectrum is the potential for providing maximum flexibility across all
three areas: displays, controls, and functionality. This calls for an HCI that
lets the operator access the loop as needed, across activities that range, for
example, from intermittent supervisory control of vehicle operations to in-
tensive tale-operation of a platform effecter via task-configurable displays
and controls. Functional capabilities also must be flexible to support a vari-
able "locus of control" between the operator and the platform. Adaptive
function allocation is one approach to this problem.
Enabling Technologies
Significant gains could be made in underwater operations regardless
of the class of platform (HOV, ROV, or AUV) if more attention were paid
to upgrading non-platform-specific assets, particularly in the areas shown
in Table 4-2.
In the platform payload area, gains are possible by developing or
adapting sensors that are smaller, use less power, and are modular. Low-
TABLE 4-2 Enabling Technology Areas
General Area
Specific Need
Platform payload
Communications
Operator display or control stations
for mission management
Sensors (especially optical imaging sensors)
Actuators, tools, and effecters
Onboard processors and associated software
architectures and algorithms
Between platform and surface
Interplatform links
Displays and controls
Decision aiding and automation
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ADDRESSING THE NEED FOR IMPROVED DEEP SUBMERGENCE ASSETS 97
power miniaturized sensors would particularly benefit HOVs and AUVs
with their limited onboard power budgets, but would also reduce tether
power requirements for ROVs. Modular sensors would benefit all three
classes of platforms because development costs are spread over a larger
population of customers and reliability would be expected to increase over
time with a larger user base. This would necessitate a greater emphasis on
standardization regarding mechanical, electrical, and software interfaces,
but the upfront costs would be rapidly recovered in recurring develop-
ment and operating savings. A similar argument can be made for stan-
dardization of interfaces for actuators, tools, and effecters.
Because of the critical importance of optical imaging sensors, they are
given separate treatment in an expanded section at the end of this chap-
ter. An area that shows particular promise for advancement is that of
onboard processing and associated software architectures and algorithms. Plat-
form-independent needs clearly exist in the following areas:
· Sensor processing, data fusion, machine-based perception, and
situation awareness
· Vehicle health management, including failure detection, diagnosis,
and recovery or reconfiguration
· Communications systems management to deal with lost link con-
. .
hngenc~es
· Mission planning, replanning for known contingencies, and dy-
namic replanning for opportunistic situations
· Improved operator display or control stations (for HOVs)
· Multivehicle coordination and cooperation algorithms and decision
aids.
1 a
To support these functional areas, and reduce the cost or time of de-
veloping future systems, there exists a real need for modular open software-
hardware architectures. The current trend for advanced embedded systems
is to work within a layered architecture (see Table 4-3) that makes maxi-
mum use of COTS hardware and software, while allowing the develop-
ment and use of mission- or domain-specialized application software
modules or application packages.
In the realm of communications, problems and solutions are driven
strongly by the presence or absence of a tether rather than the type of
platform under consideration. A tethered HOV, utilizing a small-diam-
eter fiber-optic cable to transmit video and data back to the ship, could
have considerable advantages for data gathering and recording, observa-
tion (by allowing more eyes on target), access to topside information (e.g.,
digital maps), and processing power (e.g., offboard computational facili-
ties). It is meant to be unobtrusive and to augment the mission and is
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FUTURE NEEDS IN DEEP SUBMERGENCE SCIENCE
TABLE 4-3 Layered Software-Hardware Architecture
Layer
Function and Benefit
Application
Application programmer interface
(API) middleware
Operating system (OS)
Computing hardware
Platform networking layer
Provides the functionality needed for the mission
and the vehicle via modular object-oriented
components. Proper design will support
migration of components from one mission or
vehicle to another, thus reducing code
development and validation efforts
Isolates the application layer from the operating
system below it, acting like a virtual machine for
the application software
Runs the API middleware and controls the
hardware components of the computing
platforms. Use of COTS products (e.g., Linux,
MS Windows) significantly reduces costs and
enables rapid upgrading
Runs the OS layer and consists of the main board,
central processing unit (CPU), memory, input/
output ports, and so on. Use of COTS products
(e.g., Pentium CPU) significantly reduces costs
and enables rapid upgrading
Provides connectivity between computing
platforms, enabling distributed computing. Use
of COTS products (e.g., TCP/IP [Transmission
Control Protocol/Internet Protocol], Ethernet)
significantly reduces costs and ensures
interoperability
therefore an optional capability especially for dives below 3,000m, unless
a bottom station is provided, as per the exploratory full-ocean-depth
AUV-ROV hybrid proposal from NSDF. It is important to note that a small
but nontrivial proportion of the dives may lose communication with the
surface due to snapping of the single optic cable. It is a facultative hybrid
system rather than obligate. Conversely, since untethered AUVs must rely
on bandwidth-limited, fragile, and point-to-point acoustic links, they
could clearly benefit from greater investments in onboard autonomy, al-
lowing near-real-time decisions to be made locally, making low-band-
width possible while retaining high-level operator control of the
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ADDRESSING THE NEED FOR IMPROVED DEEP SUBMERGENCE ASSETS 99
platform's operations. ROVs pose an intermediate load on the communi-
cations links: because they are tethered they can support high-bandwidth
downloads of local imagery to the operator, as well as low-bandwidth
control downloads from the operator. However, they also impose a high
workload on the operator because of the necessity of keeping him or her
"in the loop."
In the operator display and control station area, significant improve-
ments can be made, both onboard and offboard. Improved displays can
be developed by accelerating the evolution from dedicated displays where
a given display is dedicated to one or a few variables, to integrated multi-
function displays where a single piece of display hardware (e.g., a liquid-
crystal display [LCD] panel) can support different display functions (e.g.,
video imagery, subsystem status). Both provide an integrated presenta-
tion of the related variables, typically via graphical means. There is a long
history of this type of display evolution in the aerospace industry, and the
HOV-ROV-AUV industry could benefit from the lessons learned there.
There is currently disagreement among users from different fields (e.g.,
biological observers vs. geological) as to whether records of observations
should even have date-time-heading-depth information burned onto the
records. This can be avoided through the use of digital watermarks.
Improved controls could also be developed in a similar fashion via an
evolution from dedicated switches and buttons to computer-based virtual
analogs. Where physical controls are still deemed necessary (e.g., a hand
controller for a remote manipulator), multifunction controls would not
only save precious space (in an HOV) but also support more integrated
operations by the pilot or operator. Again, the aerospace industry, par-
ticularly in the high-performance military cockpit, has been a pioneer in
this area, and significant benefits could accrue from taking a more holistic
approach to HCI workspace design. Finally, improved decision aids and
automation support could enhance operations and reduce operator
workload across a range of vehicles, especially legacy HOVs and ROVs.
Some promising functional areas have been noted, in the discussion of
onboard processing and software architectures or algorithms; these are
just as valid for the offboard operator or supervisor. Naturally, the same
arguments hold true here for the use of a layered software-hardware ar-
chitecture, just as they did in the earlier discussion of on-platform require-
ments. Moreover, use of the same architecture for both onboard and
offboard computing is strongly recommended, because it not only will
lead to reduced development and validation costs overall, but also will
support flexibility in assigning the "locus of control" (i.e., on-platform
versus off-platform) as missions and technical capabilities change and
evolve over time.
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100
Optical Imaging Sensors
FUTURE NEEDS IN DEEP SUBMERGENCE SCIENCE
The strongest argument for HOVs is that there is no replacement for
in situ human three-dimensional visualization and situation awareness.
Human sensing and visual data processing allows extraction of directly
relevant and needed task information. Human presence on the scene al-
lows immediate understanding of the three-dimensional global aspects of a
site and subsequent evaluation and assessment of relationships and inter-
actions. Numerous scientific discoveries would not have been possible were
it not for observations made by scientists aboard Alvin and other HOVs.
Other advantages of HOVs include: requiring a shorter time to carry out
the same exploration in a given ocean, generating excitement, providing
educational experience, and breeding creativity and energetic scientific
thinking. HOVs will continue, however, to have viewport limitations due
to vehicle design constraints, and the associated restricted field of view
(FOV) significantly reduces the advantages of human three-dimensional
visualization. Furthermore, the heavy reliance on direct operator vision for
HOV operations can lead to observations that are undocumented by con-
ventional still or video imagery. Even when such imagery is recorded, the
limited FOV of the cameras can provide instantaneous coverage over only a
small section of the scene. To address these limitations, it is critical that a
capability exists to generate high-resolution real-time panoramic imagery
of the surrounding environment. Virtual and augmented reality systems
and tale-presence are other evolving technologies that would provide tre-
mendous potential for HOV as well as ROV operations.
Panoramic Imaging. Three existing imaging technologies provide a
large field of view, ideally 360 degrees: (1) catadioptric sensors using a
combination of lenses and mirrors in carefully arranged configurations
relative to a standard camera (Nayar, 1997; Peleg et al., 2001~; (2) collec-
tion of single-line scans or image strips from a rotating camera; (3) align-
ment of images from several cameras (Nalwa, 1996; Swaminathan and
Nayar, 2000; Negahdaripour et al., 2001; Neumann et al., 2001; Firoozfam
and Negahdaripour, 2002, 2003~. A catadioptric sensor (e.g., commercially
available omnidirectional design) can be deployed in a waterproof hous-
ing but has low resolution because the total pixels of a single camera are
distributed over the panoramic view. High-resolution scanning systems
can be either slow in imaging fast dynamical events or costly with the
high-speed precise electromechanical scanning components required to
reduce motion blur. Multicamera design each camera covering a small
section of the entire view is an attractive solution for high-resolution
precision imagery at modest cost. Multiple cameras are currently avail-
able on most vehicles but are employed primarily to switch between
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ADDRESSING THE NEED FOR IMPROVED DEEP SUBMERGENCE ASSETS 101
views. Generating panoramic views requires strategic placement of an
array of CCD (charge-coupled device) cameras and sensors, synchronized
image capture, and alignment of digitized images based on photo-
mosaicing techniques. The alignment is perfect beyond a typically small
"minimum working distance" (Swaminathan and Nayar, 2000~. Such
seamless panoramas can be constructed on the vehicle in real time with
high-speed image acquisition systems and today's PC-type processors
(currently used for tele-conferencing and video surveillance [Nalwa, 1996;
McCutchen, 1997~. If the required hardware cannot be installed on the
vehicle, raw video from various cameras can be transmitted via the tether
and processed on the surface. Though not currently available off the shelf,
enabling technology based on a single fiber-optic cable to transmit mul-
tiple high-definition quality video streams can be developed. With pan-
oramic imaging technology in place, Moore's Law (the number of transis-
tors per square inch of circuit will double every year) will ensure the
ability to incorporate more and more complex operations to improve reso-
lution and process images in real time for other capabilities (e.g., track
moving fish). Finally, stereo images can be generated from a single cam-
era with mirror reflections, enabling three-dimensional panoramic visual-
ization at the rate of several frames per second (Gluckman and Nayar,
2000~. This technology can be deployed underwater with proper housing
and calibration, significantly enhancing ROV or HOV operations, as well
as supporting various NSF initiatives for education and broad outreach.
Virtual reality. Virtual or augmented reality (VR) and tale-presence
are other evolving technologies for enhanced three-dimensional views,
peripheral vision, situation awareness, and hand-eye coordination for
manipulation tasks and education in the submergence sciences. VR sys-
tems substitute real information received by human senses for artificially
generated input, creating the impression of presence in a virtual environ-
ment. With a head-mounted display and computer generation of accurate
sensory information, a user can be given the impression of being im-
mersed in the virtual environment (immersive virtual reality) in order to
navigate and manipulate objects in that world. VR systems are currently
utilized in medicine, education and training, three-dimensional scientific
visualization (biochemistry, engineering), computer-aided design, tele-
operation and tale-manipulation, military applications (flight simulators),
art (visual, musical), games, and entertainment. In non-immersive VR sys-
tems, the user views the virtual world through monitories) or projection
screens. As the user moves, the view adjusts accordingly. "Augmented
reality" is often sufficient, replacing the real world (not completely but
only in certain aspects) with elements of the virtual environment. Realiza-
tion of VR systems is supported by the combination of several technolo-
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FUTURE NEEDS IN DEEP SUBMERGENCE SCIENCE
gies such as advanced (fast) computers, advanced computer communica-
tion networks, and HCIs. Fast computer networks enable exchange of in-
formation between remote locations, specifically, between the sensor lo-
cations and the operator displays.
Tele-presence (or virtual presence) systems extend the operator's sen-
sory-motor facilities and problem-solving abilities to a remote environ-
ment. In tale-operation, the operator also has the ability to perform cer-
tain actions or manipulations at the remote site. Traditionally, these have
required powerful general-purpose computers (e.g., Silicon Graphics,
Suns) and graphical subsystems for real-time rendering and display of
virtual environments that generate the visual stimulus. Recent develop-
ments in PC hardware and software have increased CPU (central process-
ing unit), memory, and rendering capabilities considerably, allowing
many legacy applications to migrate to much cheaper and more reliable
platforms.
Distributed VR is the enabling technology for interactions within the
same virtual world of geographically distributed networked users. Each
networked computer tracks the actions of one user and creates the illu-
sion of the user's presence in the shared virtual environment. Develop-
ment of virtual or augmented reality systems for deep submergence sci-
ence should be a high-priority research initiative that will address a
number of inherent technical complexities including, but not limited to,
visual artifacts from the movement of lights with cameras; the participat-
ing medium (water), which complicates the three-dimensional reconstruc-
tion; and the need for a very large optical dynamic range that approaches
the dark-adaptation capability of the human eye to create realistic views.
CONCLUSION
Although current assets within NDSF are not adequate (in terms of
quantity, capacity, and capability) to support some of the most promising
areas of deep submergence science, several viable options exist. The most
immediate need may be addressed by expanding access to non-NDSF as-
sets by providing limited funds to support research efforts in instances
where use of NDSF assets can be demonstrated to be a nonviable option.
Given the limited capacity of the most capable non-NDSF assets, this op-
tion cannot be considered a satisfactory long-term solution. Thus, the con-
struction of a more capable ROV system as well as a more capable HOV is
recommended.
As these new assets are developed, significant effort should go into
pursuing designs that incorporate many state-of-the-art capabilities. In
short, while Jason II has proven itself to be an important and reliable
component of the NDSF, designs for the new ROV systems called for
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ADDRESSING THE NEED FOR IMPROVED DEEP SUBMERGENCE ASSETS 103
here should incorporate a wider suite of capabilities than were incorpo-
rated in the design of Jason II. This report identifies a number of promis-
ing technologies, not all of which are mature enough to be incorporated
into any ROV or HOV built in the next two to three years. Those tech-
nologies under development in marine technology, aerospace engineer-
ing, and military fields that are not yet mature enough for immediate
implementation should be followed and considered for future genera-
tions of ROVs or HOVs.
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PHOTO 2-2: A "Black Smoker" as seen beyond Alvin 's scientific apparatus for sampling
the water chemistry of these chemically rich, high temperature vents.
SOURCE: Used with permission from J. Tromp, Woods Hole Oceanographic Institution,
Woods Hole, MA, written communication, 2003.
Representative terms from entire chapter:
submergence science
