Special Delivery: NASA's MESSENGER Sends Flyby Data to Earth Using CCSDS File Delivery Protocol Developed for Deep Space by International Team
NASA's MESSENGER team is using the CCSDS File Delivery Protocol (CFDP), a highly specialized protocol designed to overcome space operations communications challenges, to download data captured during a successful flyby of Earth last week. A team of international space data communications experts collaborating through the Consultative Committee for Space Data Systems (CCSDS) developed CFDP to reliably and efficiently downlink files from a spacecraft even in the strenuous environment of deep space.
Washington, D.C. (PRWEB) August 10, 2005 -- NASA's MESSENGER team is using
the CCSDS File Delivery Protocol (CFDP), a highly specialized protocol designed
to overcome space operations communications challenges, to download data
captured during a successful flyby of Earth last week.
A team of
international space data communications experts collaborating through the
Consultative Committee for Space Data Systems (CCSDS) developed CFDP to reliably
and efficiently downlink files from a spacecraft even in the strenuous
environment of deep space. Since the MESSENGER spacecraft's launch a year ago,
it has successfully used CFDP to enable mission communications and will use it
throughout its 7.9-billion kilometer journey to Mercury.
In using CFDP,
MESSENGER communications represents a change in the standard method of storing
science and housekeeping data on spacecraft built by the Johns Hopkins
University Applied Physics Laboratory (JHU/APL). MESSENGER is also the first
U.S. space flight mission to use CFDP in mission operations.
Prior to
MESSENGER, JHU/APL missions used a raw storage model of storing data, but new
mission and operational requirements meant that MESSENGER would have to
incorporate a file system of data storage into its spacecraft software
architecture. A reliable method of downlinking files to the ground had to be
found and CFDP was chosen by mission planners to get the job done.
CFDP
is included in the MESSENGER software architecture through a reuse of a NASA Jet
Propulsion Lab (NASA JPL) implementation on the ground and a JHU/APL “CFDP-lite”
implementation on the flight side. The NASA JPL implementation is also used on
NASA's highly successful Deep Impact mission.
“JHU/APL engineers
integrated CFDP software developed by NASA JPL into the MESSENGER mission's
ground system, which communicates with a CFDP flight software implementation
developed by JHU/APL on the spacecraft,” said Christopher Krupiarz, senior
professional staff member, JHU/APL Space Department Embedded Systems Group in
Laurel, Maryland (USA). “Being able to use an international standard like CFDP
was a key factor in getting two systems developed by two different organizations
to work for one Mercury bound spacecraft.”
CFDP is designed to function
reliably despite the long data propagation delays and frequent, lengthy
interruptions in connectivity found in deep space. It uses powerful forward
error correction coding that minimizes data loss in communication across deep
space, and also supports optional “acknowledged” modes of operation in which
data loss is automatically detected and a retransmission of the lost data is
automatically requested.
Some of the world's leading space communications
experts working within CCSDS collaborated at bi-annual working group sessions
(similar to those scheduled to take place next month in Atlanta, Georgia) to
first standardize CFDP. They defined the protocol according to space file
transfer requirements articulated by CCSDS participating space agencies,
including NASA, the European Space Agency (ESA), the British National Space
Centre (BNSC), the Centre National d'Etudes Spatiales (CNES) and the Japan
Aerospace Exploration Agency (JAXA). The protocol's ability to maintain a high
level of data transfer reliability even across interplanetary distances makes it
critical to successful communications on deep space missions like the MESSENGER
mission to Mercury and is expected to have a high level of applicability to
future Lunar exploration missions.
CFDP also benefits space flight
missions in another important way: cost savings.
CFDP allows an
instrument to record an observation in a file and transmit the file to Earth
without having to consider whether or not physical transmission is possible at
that time. Sequestering outbound data management and transmission planning
functions within CFDP can simplify flight and ground software, which reduces
mission costs - an important benefit to lower cost missions like
MESSENGER.
CCSDS will continue to foster global scale technical
cooperation to develop recommendations for space communication like CFDP that
increase interoperability, as well as reduce risk and mission operation costs.
Currently, the organization is investigating extending the use of CFDP in
emerging delay-tolerant networking technology to Interplanetary Internet
operations, and specifically to the use of CFDP in complex mission
configurations, which should further enhance the usefulness and value of CFDP to
space exploration missions in the future.
Scott Burleigh, CCSDS working
group chair and lead CFDP system engineer at NASA JPL in Pasadena, Calif.
commented, “The successes of CFDP on MESSENGER and the Deep Impact mission bring
us closer to having an automatic interplanetary communication fabric that can
support deep space science and exploration the way the Internet supports science
on Earth."
About CCSDS (http://www.CCSDS.org)
Established in 1982 by the world's
most influential space agencies, the Consultative Committee for Space Data
Systems (CCSDS) provides well-engineered international space data handling
standards that enhance government and commercial interoperability and
cross-support, while also reducing risk, project cost and development
time.
A pioneer in international cooperation in
space, the CCSDS is made up of leading space communications experts representing
28 countries, its founding member space agencies, 22 observer space agencies and
over 100 private companies. CCSDS national member space agencies include Japan,
the United Kingdom, France, Germany, Italy, Brazil, Russia, Canada and the
United States, as well as the multi-national European Space Agency.
To date, more than 300 missions to space have
chosen to fly with CCSDS protocols and the number continues to grow. For more
information on participation or to access CCSDS standards and protocols free of
charge, please visit http://www.CCSDS.org.
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Source : http://www.prweb.com/releases/2005/8/prweb270996.htm