Title: Intersatellite Communications: Considerations for Distributed Observing Systems and Mission Operatio
1Intersatellite CommunicationsConsiderations for
Distributed Observing Systems and Mission
Operations
- 4th International Symposium Reducing the Cost of
Spacecraft Ground Systems and Operations - 7th Annual Workshop Reducing the Cost of Space
Operations - Johns Hopkins University, Applied Physics
Laboratory - April 2427, 2001
- Stephen J. Talabac
- Commerce One
2Agenda
- The Drivers for Interspacecraft Communications
- Space Mission Architectures Present and Future
- Distributed Observing Systems Overview and
Mission Taxonomy - Interspacecraft Communications Architectures and
Topologies - Information that can be Exchanged
- Potential Uses and Benefits
- Potential Impacts to Mission Operations
- Some Thoughts and Candidate Recommendations
3What are the Drivers for Interspacecraft
Communications?
- NASA Near- mid- and long-term strategic plans
(2000-2025 timeframe) - HQ, Earth Science Enterprise, Space Science
Enterprise - Innovative Science Observing Concepts
- Formation Flying Missions
- Collaborative Earth- and Space-Science
Observations - Autonomous Event Recognition, Reconfiguration,
and Response - Sensor Webs
- Evolving Technologies
- MEMS microelectronics
- Electron beam lithography systems will contribute
to the development of nanospacecraft components
with extremely small mass - The challenge nanospacecraft transmitter/receiver
mass vs. on-board communications infrastructure
and power for effective RF or optical link
closure - RF, optical, and digital communications
technologies - Communications protocols standards
- Mature terrestrial protocols Network (IP, IPv6),
Transport (UDP, TCP), Application (FTP) - NASA space communications protocols CCSDS suite,
CCSDS Proximity-1, SCPS
4and a key necessity Reduce Mission Ops Costs!
- A critical impact of distributed spacecraft
missions - NASA cannot afford a linear increase in the
number of spacecraft to translate into a linear
increase in mission operations personnel ground
system costs! - Ultimate goal? - Ground system mission
operations staff for a single S/C mission is the
same as future distributed S/C mission
5NASA Strategic Plan
- Long-term plans 2012 - 2025
- Long-term benefits of the ESE program will
include 10-day weather and pollution forecasts,
5-day volcanic eruption advance warnings, 15- to
20-month El Niño forecasts, and 10-year
predictions of the regional impact of climate
change. To obtain the observations needed for
this level of prediction, NASA envisions an
intelligent network of multiple observation types
and vantage points using new technologies such as
tiny, inexpensive microsatellites and
nanosatellites. These systems will be
reconfigurable and autonomous, with overlapping
measurements for calibration and validation.
ESEs technology investment strategy over the
next 5 to 10 years focuses on the instrument,
spacecraft, and information technologies needed
to make this future possible.
6Earth Science Enterprise Strategic PlanNear-term
(2000-2005)
- NASA is pursuing architecture improvements that
include - intelligent platform and sensor control
- better space/ground communications
- linking multiple data sets to view the Earth as a
system - increasing the number of data providers and data
users in Government and the private sector. - Implement satellite formation flying to improve
science return - New Millennium Program to validate revolutionary
technologies in space.
7Earth Science Enterprise Strategic PlanMid-term
(2006-2011)
- Conduct research to achieve 7- to 10-day weather
forecasts. - Quantify the global fresh water cycle, variation
in terrestrial and marine ecosystems, and forest
and ocean carbon stocks. - Assimilate ocean surface winds, tropospheric
winds, and precipitation into climate and weather
forecasting models. - Employ distributed computing and data mining
techniques for Earth system modeling - Implement autonomous satellite control and
advanced instruments - Demonstrate a new generation of small instruments.
8Earth Science Enterprise Strategic PlanLong-term
(2012-2025)
- Conduct research to achieve 10- to 14-day weather
and pollution forecasts, 10-year climate
forecasts, 15- to 20-month El Niño forecasts, and
12-month rain rate. - Assess sea-level rise and effects and predict
regional impacts of decadal climate change. - Deploy cooperative satellite constellations,
advanced instruments, and intelligent sensor webs - Migrate selected observations from geosynchronous
and Low-Earth Orbits to libration points (L1 and
L2). - Design instruments for new scientific challenges
deploy and develop a collaborative synthetic
environment to facilitate understanding and
enable remote use of models and results. - Collaborate in an international global observing
and information system improve operational
systems with new technology.
9Space Science Enterprise Strategic Plan
- Many future mission concepts require
constellations of platforms that act as a single
mission spacecraft for coordinated observations
or in situ measurements, or act as a single
virtual instrument (e.g., interferometry or
distributed optical systems). Major areas for
work in distributed spacecraft control are
advanced autonomous guidance, navigation, and
control architectures formation initialization
and maintenance fault detection and recovery
and intersatellite communications. - Very advanced space systems will be
self-reliant, self-commanding, and even
inquisitive. These intelligent space systems must
be able to plan and conduct measurements based
on current or historical observations or inputs
recognize phenomena of interest and concentrate
activities accordingly and monitor and maintain
desired status or configuration over long periods
of time without frequent communication with
ground.
10Space Science Enterprise Strategic PlanNear-term
(2000-2005)
- Study the dynamics of the Suns atmosphere and
interior, research the interactions between the
solar wind and Earths magnetosphere, and view
solar coronal mass ejections in 3-D - Obtain images of the Earths magnetosphere during
geomagnetic storms, search for evidence of water
on Mars, and characterize the number and orbits
of Near Earth Objects. - Test two independent spacecraft flying as an
optical interferometer, and demonstrate flying
three subminiature spacecraft as a single system.
11Space Science Enterprise Strategic PlanMid-term
(2006-2011)
- Understand the detailed physics of our
magnetosphere, study physics of the outer Solar
atmosphere by flying through it, analyze detailed
structure of the magnetosphere using a
constellation with many microsatellites. - Expand understanding of space weather using
solar, radiation belt, and ionospheric mappers. - Infuse revolutionary technologies into
operational missions. Includes autonomous
robotics and sample return gossamer apertures
for imaging and spectroscopy by great
observatories, constellations of cooperating
nanosatellites, bioinformatics, and advanced
propulsion and optical communication systems for
ultra-deep space probes.
12Space Science Enterprise Strategic PlanLong-term
(2012-2025)
- Develop an integrated understanding of space
weather by deploying a network of spacecraft
throughout the Earth-Sun system. - Clarify the larger context for life in our solar
system with missions to Europa, Titan, or other
sites of potential prebiotic chemistry
13Space Mission Architecture - Today
Bent pipe communications
Science Processing Center
Science Processing Center
Graphic Credit NASA/GSFC 2000 Survey of
Distributed Spacecraft Technologies and
Architectures for NASAs Earth Science Enterprise
in the 2010-2025 Timeframe
14Space Mission Architecture - Today
- Classic stovepipe science data collection and
mission operations - Single or separate spacecraft missions with
little or no dynamic planning for opportunistic
science observations - No real time collaborative information sharing
between sensors, spacecraft, or investigators - Bent pipe interspacecraft communications
- via TDRSS in support of command uplinks,
telemetry downlinks
15Space Mission Architecture A Future Sensor Web
- Graphic Credit NASA/GSFC 2000 Survey of
Distributed Spacecraft Technologies and
Architectures for NASAs Earth Science Enterprise
in the 2010-2025 Timeframe
16Space Mission Architecture - Tomorrow
- High degree of synergy between a diverse suite of
platforms - Space-based
- Atmospheric (e.g., aircraft, balloons)
- Land (e.g., river gauges)
- Sea (e.g., buoys)
- Automated science data collection and mission
operations - On-board spectral signature detection algorithms
- Multiple spacecraft and platforms perform dynamic
planning for targets of opportunity - Real time collaborative information sharing
between sensors, spacecraft, or investigators - Interspacecraft communications becomes an
intrinsic characteristic of space platforms
17The Future Space Mission Paradigm
- The long held paradigm of deploying and operating
single spacecraft missions will be changed by the
deployment and operation of Distributed Observing
Systems. - Constellations
- Formation Flyers
- Sensor Webs
- Interspacecraft communications can offer benefits
to mission operations, however it will also
impose other challenges that must be identified,
understood, and resolved. - The increase in the numbers of spacecraft to be
monitored and controlled cannot result in a
corresponding linear increase in mission
operations costs.
18Distributed Observing Platform Concepts
STEREO stereo views of the Sun
Constellation-X the search for black holes
ST5 Nanosat Constellation Trailblazer
19A Distributed Observing System Vocabulary
- What is the terminology being used today?
- What implications do these terms have relative to
our perceptions and assumptions about what
interspacecraft communications mechanisms are
needed and why they are needed? - and the vocabulary, and the list of adjectives,
appears to be growing rapidly!
20A Distributed Spacecraft Mission
Vocabulary1There are a lot of terms out there !
- Spacecraft Aggregations
- spacecraft constellations
- homogeneous constellations
- heterogeneous constellations
- reconfigurable constellations
- string of pearls constellation
- spacecraft confederations
- clusters
- loose clusters
- swarms
- Formation Flying Vocabulary
- formation flyers
- accretionary formations
- active formations
- tight formations
- loose formations
- precision formation flying
- tandem flyers
- cooperative maneuvering
- mother ships
- drones
Note (1) List compiled and organized by Stephen
Talabac (Commerce One) and Tony Barrett (NASA/JPL)
21A Distributed Spacecraft Mission Vocabularyand
there are even more terms!
- Mission Vocabulary
- coincident mapping
- collaborative missions
- collaborative sensor webs
- cooperative missions
- distributed spacecraft
- multispacecraft missions
- multimission platforms
- scout sensors
- sensor webs
- virtual instruments
- virtual missions
- virtual platforms
- virtual webs
- Autonomy Vocabulary
- autonomy
- intelligent distributed spacecraft
- remote agent
- semi-autonomy
22Some Candidate Definitions
- Note The following examples are not necessarily
widely accepted or adopted definitions. Hopefully
they will serve to show how these terms are being
used, and what potential implications they may
have on the considerations for interspacecraft
communications and mission operations. - Therefore... dont assume that your definition
and assumed intrinsic mission characteristics are
necessarily the same as what the other person may
have in mind for the same vocabulary word.
23Constellation
- A space mission that has been formulated to
consist of two or more spacecraft and placed on
orbit for the purpose of making observations to
achieve a common science objective and where one
spacecraft alone is insufficient to meet this
objective. - Multispectral observing
- Same phenomena, multiple observation points
- Very large effective aperture observatories
- Magnetospheric mapping (i.e., multispatial,
concurrent observations) - Leonardo mission - multiple, reconfigurable
laboratories on-orbit - Stereo or long baseline interferometer
observations - Geometric (e.g., tetrahedral formation for
electromagnetic fields) - Often implies implementation of particular Earth
orbit (i.e., Walker) - Often employed by the low earth orbiting (LEO)
global communications and geolocation missions
(e.g., Orbcomm, Teledesic, GPS). - Typical interspacecraft communications topology
in-plane and adjacent plane
24Constellation ExampleTeledesic
- Boeing, Motorola and LM for launch services
- Private investors Bill Gates, Saudi Prince
Alwaleed Bin Talal - Global, broadband Internet-in-the-Sky
w/fiber-like QoS - 288 low-Earth-orbit Ka-band satellites
- 12 planes 24 spacecraft per plane at 1,375 km
altitude - Inter-satellite communication links with S/C in
the same and adjacent orbital planes. - Non-hierarchical mesh, or "geodesic," network
tolerant of faults and local congestion - Planned service beginning 2003
- D/L at 64 Mbps U/L at 2 Mbps.
25Constellation ExampleGlobal Star
- International consortium of telecom providers
- Voice, data, fax, messaging and other telecom
services - Orbital characteristics
- 48 spacecraft 8 planes, 6 S/C per plane 4 spare
S/C - 1,414 km, 520 inclination - coverage 700N to 700S
latitude - Communication between user and S/C via gateway
- No S/C-to-S/C communications
Graphic Globalstar
26ConstellationsHomogeneous or Heterogeneous?
- Homogeneous Constellation
- Constellations whose member spacecraft employ
identical bus, payload, and operational
characteristics. - The spacecraft are, in essence, clones of one
another and may be mass produced. - Not meant to imply that they are all placed
on-orbit all at the same time. - Heterogeneous Constellation
- Constellations whose member spacecraft employ
different bus, payload, and perhaps operational
characteristics. - Implications for interspacecraft communications
- Communications protocol standards to promote
heterogeneous spacecraft network interoperability
27Reconfigurable Constellation
- A distributed spacecraft observing system that
possesses the ability to change one or more
intrinsic characteristics while on orbit. - Example Leonardo ESE laboratory in space
- Some of these characteristics may include any or
all of the following - Orbit
- Attitude
- Relative spacing
- Coordination of observations with other
spacecraft - Cluster size
- Virtual laboratory instrument suite to be used
for conducting an observation - Implications for interspacecraft communications
- Adaptable/reconfigurable/multiple communications
protocols - RF range to achieve link closure, line-of-sight,
orbital relationships - Pointing control, knowledge of whereabouts of
other spacecraft
28Formation Flyer
- Two or more spacecraft that conduct a science
mission such that the relative distances and 3D
spatial relationships (i.e., distances, angular
relationships, relative velocities between all
spacecraft) are preserved for the respective
orbits of all spacecraft that comprise the
formation. - Formation flyer configurations may be desired or
required to meet certain science objectives. - Interferometry
- Large Effective Apertures
- Measure Electromagnetic Field Vectors
- Implications for interspacecraft communications
- Pointing vs. omnidirectional signal propagation
- Multicast or broadcast protocols
- Reliable data transfer protocol critical for
formation control - Half vs. full duplex links to meet mission
operations scenarios
29Additional Formation Flyer terms
- Tight and Loose Formations
- Subjective descriptions of the degree precision
and accuracy needed to be maintained between the
spacecraft that comprise the formation - Precision Formation Flying
- A subjective term referring to the required
preciseness required of a particular formation - There do not appear to be any particular set of
objective metrology standards as what exactly
constitutes precise - Tandem Flyers
- Two or more spacecraft that follow one another in
the same orbital plane. - Accretionary Formation
- A distributed spacecraft mission whose individual
S/C members are added to the mission over time.
30An Accretionary FormationThe EOS AM-Train
- A formation that comes into being or evolves
into a constellation as additional spacecraft are
placed on orbit - No preconceived plan to create constellation from
the outset - The EOS AM Train Landsat-7, EO-1, Terra, SAC-C
- The EOS PM Train Aqua, Aura, Cloudsat,
Picasso-CENA
31Formation Flyer Large Effective Aperture
ObservatoryConstellation-X
- Next Generation X-ray Observatory
- 4 identical spacecraft
- Two coaligned telescope systems per spacecraft
- Yields large effective X-ray collecting area
- 3 year mission design 5 years desired
- Orbit outer Lagrangian point L2
- Avoids earth thermal interference and X-ray
source occultations
Graphic NASA/GSFC
32Formation FlyerLaser Interferometer Space
Antenna (LISA)
- Mission
- Observe gravitational waves from galactic and
extra-galactic binary systems - 3 S/C flying 5 million km apart in the shape of
an equilateral triangle. - Lasers in each spacecraft will be used to measure
changes in the 5 million km optical path lengths
with a precision of 20 picometers. - Core technologies
- Inertial Sensors
- Micronewton Thrusters
- Laser Interferometry
- Planned launch 2008
33Mission Architecture NomenclatureMotherships and
Drones
- Mothership
- Presupposes a specific constellation architecture
where a particular spacecraft serves as the
central focal point for the constellation
communication, and/or as general coordinator of
all constellation activities. - It may or may not initiate commands or act on
drone telemetry data (engineering HS or
instrument payload data) - It may serve as
- a way station for store-and-forward or
bent-pipe communications to/from Earth - a centralized computational engine and large
capacity mass store for the mission - Drone
- Presupposes a specific constellation architecture
where particular spacecraft serve as the arms
and legs of a constellation - Makes and reports observations and status to the
mothership - Accepts and acts on mothership commands
- Mothership routes telemetry data to Earth and
accepts commands from Earth
34A Taxonomy of Constellation Orbits
- Constellation orbits
- Will be a key driver relative to how
interspacecraft communications may be conducted. - Orbits and S/C configurations within orbits will
impact the ground segment and mission operations
support. - Based upon JPL study
- Multiple Mission Platform Taxonomy A. Barrett
JPL/CIT, Jan. 30, 2001
35LEO Aggregations
Constellation
String of Pearls
Cluster
36Elliptical Orbit Aggregations
Constellation
String of Pearls
Cluster
37Lissajous Orbits
L2
1.5 million km
1.5 million km
Sun-Earth Line
L1
38Interspacecraft Communications TopologiesConstell
ations
Adjacent planes
39Interspacecraft Communications TopologiesClusters
40Interspacecraft Communications TopologiesString
of Pearls
41Architectural Implications for Interspacecraft
Communications
- Constellations
- Knowledge of the whereabouts of member
spacecraft within their orbits is reasonably well
constrained. - Spacecraft immediately ahead of or behind
another in the same orbital plane - Phasing relationships between spacecraft in
adjacent planes - Homogeneous Constellations
- Communications infrastructure is inherently the
same - Simplifies communications architecture since
theres only one solution set implemented for the
protocol stack (e.g., ISO/OSI 7 layer model
components) - Heterogeneous Constellations
- Drives need for standard communications protocol
stacks - Facilitate interoperability between S/C and
ground segment - Reduce mission implementation and ops costs
- Mitigate implementation risk
42Architectural Implications for Interspacecraft
Communications
- Formation Fliers
- Knowledge of relationship between S/C that
comprise the formation may simplify
communications architecture - Point-to-point
- Broadcast
- Proximity
- May permit low power communications especially
important for low mass nanospacecraft - Accretionary Formations
- Since they are not a priori known to come into
being, standards are a must for communications
protocol layers 1-4, 7 if these S/C might
eventually communicate among one another
43Information that Needs to be Exchanged
- Spacecraft and Instrument HS Telemetry Data
- Characterized by relatively low data rates, low
volumes - Spacecraft operational status messages
- S/C orbit and attitude information
- Instrument(s) mode(s) of operation
- Instrument Pointing information
- Spacecraft Instrument Data
- Can be characterized by relatively high volumes
and high data rates - Typically unidirectional
- Collaborative missions may require bi-directional
science data exchange - May be used to facilitate distributed space-based
computing - On-board spectral (signal) signature processing
- Event recognition software
- Event response software
- Duty cycle will depend upon mission needs
44Information that May be Exchanged
- Ancillary information
- Most likely characterized by low rate, low volume
- Interspacecraft range and range-rate
- Status messages that facilitate or help to
coordinate science observations, on-board
processing status, etc. - Science instrument calibration coefficients/tables
- Rate of data exchange and duty cycle of link
utilization will depend upon individual mission
needs
45Mission Needs Ops Concepts will Drive Protocol
Issues
- Differences between space terrestrial
communications environments - Spatial relationship between two communicating
S/C is continually changing - In and out of RF range
- In and out of line-of-sight
- Changing pointing angles
- Available (on-board) communications transmitter
power to close the link - Directional (RF,Optical) less transmit power
pointing knowledge required - Omnidirectional more transmit power required
broadcast can create duplicate packets in network - Handling lost packets
- Terrestrial networks assume congestion slow down
packet traffic to compensate - Space networks assume noisy link re-transmit
packet as soon as practicable - Propagation delays can be (but are not
necessarily) longer
46Mission Needs Ops Concepts will Drive Protocol
Issues
- IP, UDP/TCP, FTP
- Mature, robust, open layered protocol
architecture - In wide commercial use for terrestrial
applications - Promotes interoperability between space and
terrestrial networks - Widespread use promotes lower ground system
implementation costs - Mitigates implementation risk and shortens
implementation schedule - Familiarity (terminology, concepts, usage) with
user community - Out-of-the box implementation of TCP slow-start
algorithm may not be suitable to every space
mission - CCSDS
- Mature and in wide use for NASA space missions
- Interoperability with other foreign space- and
ground- networks - Well adapted to noisy space communications
environment - SCPS and Proximity-1 emerging to address current
protocol deficiencies vis-a-vis terrestrial
protocols use in future constellation
communications.
47Interspacecraft Comms Potential
Uses/BenefitsFor S/C presently not within view
of a ground station
- Route all uplinks to the S/C that is within view
of ground station - Ground station antenna and support equipment
- S/C contact activity planning scheduling
independent of ground station - GEO-like nearly-continuous contacts may be
possible with any S/C - An increase of the uplink data rate may be
required to serve multiple S/C - Multiple S/C yield aggregate downlink data rates
that may necessitate wider bandwidth (i.e.,
higher data rate) to the ground - Uplink route commands to one, some, all
spacecraft - Routine, emergency
- Receive HS engineering telemetry
- Routine, emergency out-of-limits
- Receive science instrument data
- Potential bandwidth problem if high rate, high
volume
48Interspacecraft Comms Potential Uses/Benefits
For S/C presently within view of a ground station
- Formation flying or cluster missions
- Contact with just one S/C in the cluster may
eliminate multiple, successive uplink contacts
for each S/C in cluster - Uplink one set of commands to mothership which
serves as a router-in-space for all drone
spacecraft
49Interspacecraft Comms Potential Uses/Benefits
- Independent of ground station view
- Unplanned science events, opportunistic science
- Automated identification (e.g., autonomous
spectral/signal detection) - Autonomous mission reconfiguration
- Notify or cue other spacecraft to conduct
coordinated observations - Event notification to mission operations
- Especially when S/C is not in view of ground
station for long times (e.g., highly elliptical
orbits) - Anomaly identification and resolution
50Mission Operations Present and Future
- The present
- Mission operation are simple (e.g., SMEX, survey
missions) to challenging (e.g., HST, AM-train)
depending upon mission design and ops concept - The future
- Challenging even for relatively simple (e.g.,
survey) mission designs - Multiple S/C for each mission
- More complex mission observation planning
scenarios - Potentially increased time to plan ground station
contacts and create command loads - Increased impact on ground station resources
(e.g., antennas) - Shorter duration between contacts for formation
flyers or clusters - Larger aggregate return link data volumes
51Potential Impacts to Mission Operations
- If interspacecraft communications requires
pointing and if it is not performed autonomously
on-orbit - Plan and schedule contact times and pointing
angles for communicating S/C - Additional mission ops responsibility and ground
resources to plan, schedule, and upload
communications activity commands and data - Times when S/C can communicate
- On-board resources required
- Pointing information
- Monitoring system performance, especially when
things go wrong - Additional engineering HS telemetry data
relative to comms subsystems to monitor and
interpret - Transmitter/receiver status
- On-board data buffer utilization (e.g.,
packets/files sent/received) - Communications traffic volume, duty cycle
- Communications error rates
- Reconfigure the communications network between
spacecraft to facilitate work-arounds,
degradations, failures
52Potential Impacts to Mission Operations
- Data routing to the ground from a S/C not in view
of a ground station - Are ground equipment resources available?
- Antennas and front-end electronics
- Front-end processors
- Ground data storage
- Communications networks
- Planning science observations becomes
intrinsically more complex and more than one
observation scenario may be available due to
multiple S/C. - Need robust science observation activity
planning, scheduling, resource utilization, and
conflict resolution tools - Simulators may be used to better identify and
evaluate several alternative what if scenarios - Rule-based assistants may evaluate and
recommend optimal performance criteria depending
upon mission complexity - On-board recorder management becomes more complex
53Potential Impacts to Mission Operations
- Commanding
- Increases in complexity if the mission permits
commands to be routed to S/C other than those in
view of the ground station. - Protocols such as IP (and IPv6 with multicasting)
could be beneficial if suited to mission
parameters - Telemetry monitoring
- If routed through the constellation, telemetry
data may be available nearly continuously from
all S/C not just during those periods when a
pass occurs. - Impacts ground system resource utilization and
mission ops personnel utilization. - Today after loss-of-signal, ground resources are
often released, and reconfigured. Mission ops
personnel perform other functions when no S/C
contact is in progress. - Tomorrow But what if spacecraft contacts were
effectively continuous from multiple spacecraft?
54Potential Impacts to Mission Operations
- Navigation planning
- Tight formations will likely require high
fidelity simulations to ensure collision
avoidance and to test various what if
navigation alternatives.
55Conclusions and Candidate Recommendations
- Alternative mission architectures, as well as
functional and performance objectives for
distributed space observing systems require a
variety of interspacecraft communications
solutions - Regardless of the details, mission operations
ground resources and especially mission
operations staff workload will be impacted
without the luxury of increased mission
operations budgets - Greater on-board autonomy and more effective
ground-based automation will be beneficial and
contribute to alleviate the impact to mission
operations - Simulation software will be highly desirable by
helping to identify alternative mission scenarios
and to objectively and quantitatively assess
specific impacts upon science missions in the
design and operational phases - Introduce advanced concepts into control centers
and ground systems - Goal-oriented commanding
- Mothership may serve as central relay for drones
- Automated TTC and mission operations systems
(e.g., expert or rule-based systems)