NASA demos space Net
- By Paula Shaki Trimble
- May 01, 2000
NASA's faster, better, cheaper concept may get a boost from the Internet
boom. A recent demonstration using commercial off-the-shelf networking products
and standard Internet Protocol (IP) to communicate with an orbiting satellite
is the first step in designing space missions more quickly, more cheaply
On April 10, engineers from NASA's Goddard Space Flight Center, Greenbelt,
Md., used Internet ping packets — small data packets sent to a node on the
Internet with instructions to reply — to communicate with an orbiting UoSAT-12
satellite. Currently, communications with spacecraft take place using expensive
hardware and proprietary protocols.
Federal agencies such as NASA, the National Oceanic and Atmospheric
Administration, the Defense Department and the National Imagery and Mapping
Administration are just a few that could benefit by communicating with spacecraft
using the same standardized, low-cost equipment used for ground-based networking.
"Just the fact that we've established IP connectivity with a spacecraft
opens a whole world of options to spacecraft designers," said Ronald Parise,
senior scientist for Computer Sciences Corp., which is a contractor on the
project at NASA's Information Systems Center.
The project also is sponsored by NASA's Communications Technology Project
of the Space Operations Management Office.
The project, called Operating Missions as Nodes on the Internet (OMNI,
on the Internet at ipinspace.gsfc.nasa.gov), was developed to dispel myths
that IP does not work in space.
"Industry is putting billions into network research," Parise said. "Why
shouldn't we take advantage of that?"
Currently, data for most NASA missions is delivered from ground stations
to users via IP backbones, but the links between ground stations and spacecraft
require expensive specialized hardware and unique, custom protocols to package
the data, said Edward Criscuolo, senior computer scientist for CSC on the
Currently, there are two methods used for this spacecraft-to-ground
station link. With older space missions, computers on spacecraft break up
their data into small pieces, place it into frames and transmit it to the
ground station over a wireless radio frequency network. On the ground, the
frames are inserted into so-called Nascom 4800-bit blocks, converted to
IP and distributed via the Internet.
Some newer satellites package their data into CCSDS packets before transmitting
it to the ground. CCSDS is a standard format developed by the Consultative
Committee for Space Data Systems, an international standards organization.
Once received by the ground station, the CCSDS packets are inserted into
Nascom 4800-bit blocks and delivered via the Internet.
In the recent demo, the UoSAT-12 satellite sent its data to the ground
station in standard IP packets, eliminating the need to convert the data
from the proprietary formats on the ground. With this scenario, IP packets
could conceivably flow unmodified from an instrument on the satellite to
any end user, which could give scientists virtually direct access to the
Eliminating the need for intermediate data processing will save significant
mission costs, NASA and contractor officials said.
"It's cheap, it works and it solves the problem," Criscuolo said.
The technical challenges of operating space missions as nodes on the
Internet can be overcome, said James Rash, OMNI project manager for NASA.
While commercial products designed to survive the radiation in space and
support the standard protocols still need to be developed, the major obstacles
are political and cultural, he said.
The demonstration of IP connectivity was the first in a series of tests
to establish the capabilities needed to do real missions, Rash said.
Automatic spacecraft clock synchronization was demonstrated April 14
using the Network Time Protocol, which will allow a spacecraft to access
the U.S. Naval Observatory's World Wide Web site to calibrate its own clock.
Another test next month will use standard File Transfer Protocol to test
reliable file transfers. Simple Mail Transfer Protocol will be used to demonstrate
automated file store and forward tasks.
In the future, some of the most important technologies needed to support
full operational deployment of Internet protocols for future space missions
will be tested. They include mobile IP, IP security mechanisms and multicast
Advanced mission concepts, such as fleets of small satellites that are
coordinated to take images of Earth, are cost-prohibitive using custom communications
protocols, Rash said.
"Going to IP facilitates formation flying [of satellites], distributed
control and constellation management," Criscuolo said. Existing protocols
were designed for communications from the ground to the satellite and back,
not for communications between spacecraft.
Frank Bauer, chief of the Guidance, Navigation and Control Center at
Goddard, has a vested interest in OMNI's work because it will promote the
control of distributed spacecraft as well as distributed operations.
"It's important that we try to use as much of the infrastructure that's
already in place domestically in space," he said.
Eventually, those capabilities could be expanded to an Internet-like
network of spacecraft around Mars or an Interplanetary Internet.