Transcript Cislunar for CCSDS COS - The CCSDS Collaborative Work

The CCSDS Cislunar
Communications Architecture
Keith Scott
The MITRE Corporation
CCSDS Meeting
January 2007
Agenda
• CCSDS Cislunar Space Internetworking Working Group
Scope and Charter
• Current Mission Architecture
• Future Mission Scenarios
• Networked Communications
• Terrestrial Interoperability
CCSDS Cislunar Space Internetworking
Working Group
• Chartered to produce a communications architecture for cislunar
(between the Earth and the Moon) communications
– Includes robotic Earth-observing and lunar missions
– Includes crewed Earth-orbital and lunar missions
– Where possible, should extend to comparable in-situ environments
Mars-Specific Communications
~10s RTT
Cislunar
Communications
ce s
pa tion
S
ep ica
De mun
m
Co
moon
0.38s RTT
EML1
2.5 sec. RTT
~10s RTT
Cislunar
Communications
EML2
0.43s RTT
ard
nw
u
S
SEL2
< 0.05 sec. RTT
Deimos
10 sec. RTT
Phobos
Limit of Earth-centered
Cislunar range for this
study.
10 sec. RTT
Limit of Mars
-centered Cislunar
range for this study.
ard
nw
u
S
TT
.R
ec
6s
6
.
6
SML2
Current Mission Architecture
RF
C&DH
1553
Inst
MCC
Subsys
Inst
Future Missions?
Current Relay Comms
Orbiter Deep Space Link:
• Data rate (~power x gain)
• Frequency (X, Ka)
• Range variation (25x comm performance)
Proximity Link:
• Frequency band
• Comm protocols
• Multiple Access Scheme
Adapted from Wallace Tai’s IOAG presentation, June 2004
Current Relay Comms
Orbiter Deep Space Link
Data Link
Physical
Adapted from Wallace Tai’s IOAG presentation, June 2004
Data Link
Proximity Link
Physical
Link
Data
cal
Physi
Link
a
t
a
D
cal
i
s
y
h
P
Networked Communications
•
Multi-Hop
– “Route around” obstructions
– Heterogeneous links tuned to the environment
•
Global Addressing
– Applications don’t have to worry about where the
destinations are or how to get there
•
Automated data forwarding
– Fewer commanded data movements
•
Efficient multiplexing of many applications
Application
Network
Application
Network
Network
Data Link
Data Link
Data Link
Data Link
Physical
Physical
Physical
Physical
Forwarding IP Packets
10.1.0.0/16
10.1.0.2 10.1.0.5
10.4.0.0/16
10.4.1.3
Destination
Next Hop
10.2.0.0/16
10.4.0.1
10.3.0.0/16
10.4.0.1
10.4.1.9
10.4.1.1
Destination
Next Hop
10.1.0.0/16
10.1.0.2
10.2.0.0/16
10.4.1.3
10.3.0.0/16
10.4.1.1
10.3.0.0/16
10.2.0.0/16
Routing Protocols
I can reach
10.1.0.0/16
10.1.0.0/16
10.4.0.0/16
Destination
Next Hop
10.2.0.0/16
10.4.0.1
10.3.0.0/16
10.4.0.1
I can reach
10.1.0.0/16,
10.3.0.0/16
10.2.0.0/16
I can reach
10.2.0.0/16
I can reach
10.2.0.0/16
I can reach
10.3.0.0/16
I can reach
10.1.0.0/16
10.2.0.0/16
I can reach
10.3.0.0/16
10.3.0.0/16
Mixed Architectures
• Applications should still have access
to data-link-specific services, they
just aren’t end-to-end services
Application
Network
Application
Network
Application
Network
Data Link
Data Link
Data Link
Data Link
Physical
Physical
Physical
Physical
Which Network Layer?
• Choices include
–
–
–
–
–
IP
ATM
IPX
AppleTalk
…
• Advantages of IP
– NOT connection-oriented (don’t need end-to-end signaling to set
up path)
– Wide availability of implementations / hardware
• Including small implementations suitable for flight software
– Interoperability with ground infrastructure
• Simplifies testing / verification
Other Topics in Green Book
•
•
•
•
Quality of Service
Security
Emergency Commanding
Overlay Communications
Terrestrial Data Transport
• What support is needed in the ground infrastructure to
support IP-based missions?
• Spacecraft built by AgencyA that uses IP networking
using AgencyB’s ground station
– Several options, depending on ground station capabilities and
inter-agency connectivity characteristics
• Space Link Extensions return-all-frames and return-channel-frames
services being prototyped now by NASA, ESA, JAXA
• Direct routed IP from the ground station
– What changes would this require at ground stations?
– What are the constraints on inter-agency connections (security, QoS)?
• Tunnel IP datagrams from ground station to mission operations
– What changes would this require at ground stations?
– What are the constraints on inter-agency connections (security, QoS)?
Interoperability Via SLE
G/S
AOS
S/C
SP Data
AOS
AOS
SLE
AOS
MCC
CCSDS Space Packets
SP Data
CCSDS VC
SP Data
AOS
IP SLE SLE Payload
SP Data
CCSDS VC
IP SLE SLE Payload
IP SLE SLE Payload
• Space link terminates at MCC
• SLE characteristics (latency, jitter) are considered part of the space
link characteristics
• IP datagrams, CCSDS Space Packets, … SLE doesn’t care
Interoperability Via SLE
AOS
S/C
G/S
AOS
SLE
AOS
IP
MCC
IP Packets
IP Packets
Network
IP
Data
IP
Data
SP Data
IP
AOS
CCSDS VC
AOS
IP SLE SLE Payload
SP Data
Data
IP
Data
CCSDS VC
IP SLE SLE Payload
IP SLE SLE Payload
• Space link terminates at MCC
• SLE characteristics (latency, jitter) are considered part of the space
link characteristics
• Can mix IP and Space Packets
Interoperability Via SLE
G/S
AOS
S/C
IP
Data
AOS
AOS
SLE
AOS
IP Packets
MCC
CCSDS Space Packets
IP
Network
Data
CCSDS VC
IP
IP
AOS
IP SLE SLE Payload
IP Packets
Data
IP
Data
CCSDS VC
IP SLE SLE Payload
IP SLE SLE Payload
• Space link terminates at MCC
• SLE characteristics (latency, jitter) are considered part of the space
link characteristics
• Can mix IP and Space Packets
IP Tunnel
AOS
S/C
G/S
IP
GRE
IP
IP
MCC
IP Packets
IP Packets
Network
IP
Data
IP
AOS CCSDS
Data
Channel AOS CCSDS Channel
IP GRE IP
Data
IP GRE IP
Data
IP
Data
IP
Data
• Space link terminates at Ground Station
• Forces traffic through Mission Control Center
• Different latency / jitter characteristics than SLE tunnel
Downlink Return Via IP
AOS
S/C
IP
Data
AOS
IP Packets
IP
G/S
IP Packets
MCC
IP
Network
Data
CCSDS VC
AOS
CCSDS VC
IP
Data
IP
Data
• Space link terminates at the ground station
• IP traffic delivery over the inter-agency cloud
• Implications for security / uplink stream formation
Mixed Approach
AOS
S/C
IP Packets
IP Packets
CCSDS Space Packets
G/S
AOS
SLE
AOS
MCC
CCSDS Space Packets
IP
Data
AOS
IP
Data
CCSDS VC
AOS
IP SLE SLE Payload
CCSDS VC
IP SLE SLE Payload
IP SLE SLE Payload
• The approaches above can be mixed.
IP
Network
Conclusions
• A network layer unifies possibly heterogeneous data
links
• Automated data forwarding simplifies operations over
what we do now or might do using current protocols
• An IP-based system leverages commercial technologies
and can leverage the terrestrial infrastructure
• An IP-based infrastructure can handle the range of data
types we currently envision and has shown flexibility in
the past
• The technical issues with an IP infrastructure in space
are addressable
• It’s possible to mix-and-match new routing components
alongside traditional operations in the same spacecraft
and terrestrial systems
Status
• Green book (architecture) done and about to be
submitted to CESG for review (final editing completed
last week)
• Starting first Recommendation dealing with ‘simple’ IPbased spacecraft operations
– Focus on terrestrial interoperability
Questions?