NASA demos space Net

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

and smarter.

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

OMNI project.

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

satellite.

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

data distribution.

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.