24 Jan 2009 (updated 24 Jan 2009 at 19:04 UTC)
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Our work in space in 2008
A new year has started. What happened around the Cisco
router in Low Earth Orbit (CLEO) in 2008? I looked back,
and found quite a lot; I thought it might be interesting to
summarise it.
We look back on five years of our testing around CLEO in a
short retrospective paper: Investigating
operation of the Internet in orbit: Five years of
collaboration around CLEO.
The CLEO router and the UK-DMC satellite that CLEO lives on
were launched into
orbit on 27 September 2003, and passed five years on
orbit on 27 September 2008. Five years is the design
lifetime of these DMC satellites, so the router and
satellite are exceeding expected life. (We powered up CLEO
and tested it on 24 September and 22 October 2008.) UK-DMC's
similar sister satellite AlSAT-1 has already passed six
years working in orbit (launched November 2002), so we can
hope to be using CLEO and the UK-DMC satellite occasionally
as test platforms for some time to come.
The team of NASA
Glenn Research Center, Cisco Systems and
Surrey Satellite Technology
Ltd (SSTL) has gone on from focusing on testing the CLEO
router to developing and testing Internet-Protocol
(IP)-based communications from space, using the CLEO testbed
at NASA Glenn to develop code later uploaded to a computer
on the UK-DMC satellite. NASA Glenn has been working on modifications
to SSTL's Saratoga protocol for delay-tolerant
networking.
The team has provided a specification of Saratoga,
used daily to transfer remote-sensing images from space over
IP, to the Internet Engineering Task Force in
Saratoga:
A Scalable File Transfer Protocol, work in progress as
an internet-draft.
We also looked at modifying Saratoga to carry the
'Bundle Protocol' developed by the Delay-Tolerant Networking
Research Group, in
Using
Saratoga with a Bundle Agent as a Convergence Layer
for Delay-Tolerant Networking, work in progress as an
internet-draft.
We tested the Bundle Protocol from space over
Saratoga from the UK-DMC satellite, first,
revealing some problems in design and implementation, in
January 2008, and then successfully in August 2008 - and
then announced
that success in September. These tests are summarised in
a paper we've now sent to the International Journal of
Satellite Communication and Networking:
Experience
with delay-tolerant networking from orbit.
Our thoughts on the design of the Bundle Protocol itself,
based on our practical experience, are written up in a paper
to be presented in March at the IEEE Aerospace conference:
A
Bundle of Problems.
We are the
first to test this Bundle Protocol from space -
significant because the Bundle Protocol is 'blessed' as the
way NASA's future 'Interplanetary
Internet' is intended to communicate.
This led to our
tests being mentioned by Time Magazine in November 2008
when they made the "Orbital
Internet" one of their top ten inventions of 2009.
NASA's Jet Propulsion Lab has now also tested the Bundle
Protocol in space on their Deep Impact/EPOXI probe, and
announced this 'first
deep space Internet' later in November. Those tests used
their CCSDS protocols in communications to and from space,
rather than the Internet Protocol that CLEO and the DMC
satellites rely on.
Cisco is also readying its IRIS Internet Router in
Space for launch to geostationary orbit on the
Intelsat-14 satellite this year.
The success of CLEO helped make planning IRIS possible.
It's been a busy 2008. 2009 should be interesting.