Transcript Computing for Space Science - Current practice and future challenges

Computing for Space Science –
Current practice and future challenges
Peter Allan
Head, Space Data Division
Overview
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Brief overview of work of SSTD
Software, data, archives
Systems in space
Challenges for the future
Work of SSTD
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Astronomy and Earth Observation
Design studies
Design, build and test instruments
Launch instruments (e.g GERB on Wednesday)
Science Operations
Communicate with spacecraft
Develop data processing systems
Process, archive and disseminate data
Long term data curation
Telescope pointing
GERB
Calibration Monitor
Scan Mirror
Quartz Filter
Front End
Electronics
Earth
View
Telescope
Fold mirror
and detector
Internal blackbody
18g
Launches
RAL Ground Station
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RAL antennae 12m plus 2.4m
Chilbolton 25m
Jodrell Bank 76m
NASA DSN
– several hundred 10m-class
antennae ?
Ground Stations
• Equipment controlled by
standard PC
• Standard protocols are the
key
– Developed by CCSDS
• Like IP, but tuned for use in
space
– Must handle long round trip
times (many mins to hours)
– Must handle disjoint
connections
– Power is always at a premium
Science Operations
Operations on Cluster
Double Star
Mars Express
General Computing
• Windows and Linux on desktop
– A few Sun and HP workstations
• Linux, Solaris and Tru64 on science servers
• Windows servers for office system and
technical tools (e.g. CAD)
Data Centres and Archives
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British Atmospheric Data Centre
NERC Earth Observation Data Centre
Cluster/Doublestar
UK Solar System Data Centre
– Solar data
– Data on Ionosphere
– Space plasma data
Software Engineering
• ISO 9001
• Apply the “appropriate level” of rigour
• Use appropriate methods
– Iterative development
– Science code  industrial strength app
– Develop formal requirements
• Workshops on improving processes
– Use of standard tools?
– Departmental CVS repository?
Operating Systems for Space
• Operating systems for space
– H/W is previous generation
– No disk drives
– Tapes replaced with solid state memory
– Still use assembler for some applications
– Starting to use unix-like systems
– Web server in space
Data Analysis and Visualisation
• Languages
– Fortran, C,
C++, Java,
Perl, Python
• IDL
– ENVI
Data Processing and Analysis
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Starlink
GGSPS
AstroGrid
NERC data grid
Starlink
• Software for processing
astronomical data for
nearly all wavelengths
• Integrated data
processing tools
• Library for writing new
tools
• Uniform data format
• Fortran  (+C) 
Java
• Lasted for 26 years
GGSPS
• GERB Ground Segment Processing System
• Multi-national data processing system
– Germany  RAL  Belgium  RAL  Users
• Written in C++ (mostly not OO)
Satellite rotation period = 0.6 s
282 steps for full Earth disc = 169.2 s
2 channels: Total
Total+quartz filter (SW)
256 detector pixels
Average three scans in
each channel to improve
S/N
Total repeat time =
169.2*6 ~ 15 min.
Between each Earth scan,
internal BB measurement taken
for calibration
282 steps
At correct viewing geometry,
calibration monitor records
scattered solar light as a
relative measure over time
Future Challenges
• Autonomy
– Rovers on Mars
– On board analysis of satellite imagery
• Interplanetary Internet
• Integrating Grid computing into daily work
Interplanetary Internet
• Spread communications infrastructure
throughout solar system
• E-mail [email protected]
• Need the right protocols
– Long round trip times!
Grid Computing
• AstroGrid
• NERC Data Grid
• Both about improving access to data
– Search, merge, analyse
• Hooked into international data sources
– IVOA
Grid Computing
• Examples from AstroGrid
– Improving access to data
– “What if” questions answered in minutes,
not months
– Enabling rapid response to sudden bursts
Optical Data Archive
X-ray Data Archive
Processing
Pipeline
Astronomy from the Desktop
multi-l
views of a
Supernova
Remnant
Shocks seen in the Xray
Heavy elements
seen in the
Dust seen in the IR
Relativistic electrons
seen in the radio
Needles in a haystack
- faint moving object is a cool white dwarf
- may be solution to the dark matter problem
- but hard to find : one in a million
- even harder across multiple archives
Hambly et al 2001
yesterday
web
page
CGI
request
SQL
front
end
browser
html
DB
engine
data
application
anything
today
SQL
SOAP/XML request
standard formats
SOAP/XML data
web
service
DB
engine
native
data
web
service
tomorrow
job
standard
semantics
results
Registry
Workflow
GLUE
Certification
VO Space
grid connected
application
anything
web
service
web
service
web
service
web
service
web
service
Image from
ESO
SWIFT satellite
observes gamma
ray burst
Gamma Ray Bursts
Interaction with
observatory pipelines
Localise GRB alert
in minutes – as
fade
rapidly.
Cross reference multiλ
data – ID pre-cursor
and or environment
Image + IRIS data
Large computational
photometric redshift
calcs on multi-λ
> gives distance
Collate data from
multiple telescopes
over months meta data issues
Compare against SN
light curves – bump
shows eveidence
for a SN in the GRB
(Price et al, 2002)
Reprocessing of
ionospheric STP data
change coords
from earth to
D. Ducros, ESA
Questions ?
yesterday
web
page
CGI
request
SQL
front
end
browser
html
DB
engine
data
application
anything
today
SQL
SOAP/XML request
standard formats
SOAP/XML data
web
service
DB
engine
native
data
web
service
tomorrow
job
standard
semantics
results
Registry
Workflow
GLUE
Certification
VO Space
grid connected
application
anything
web
service
web
service
web
service
web
service
web
service