IPN Frequently Asked Questions

We're working on filling this section with answers to all your questions about the IPN. These are just a few of the questions we're already working on...

How does IPN research relate to emerging terrestrial internet protocols?

Security: In the terrestrial Internet, security has become a high priority need. This is because of the tremendous growth in ubiquitous connectivity and electronic commerce. Users are constantly being asked to authenticate themselves with a username and password. However, sending this information over the Internet without using security protections means that they can be intercepted and captured, completely compromising security.

Terrestrial Internet security has been moving forward on three fronts: IP layer security (IPSEC), Secure Sockets Layer (SSL)/Transport Layer Security (TLS), and secure electronic mail using S/MIME or PGP. These security mechanisms, while operating at different layers of the Internet protocol suite, provide security service such as confidentiality, integrity, authentication, and non-repudiation. The Interplanetary Internet also requires security services to provide protection.

However, the IPN differs from the terrestrial Internet in that there is little bandwidth available and connectivity is not always guaranteed between IPN entities. As a result, the security mechanisms implemented in the IPN cannot assume that they can interact with their peers in an on-line, interactive fashion. Rather, they have to operate in the IPNs "pony-express" model of operation. This is quite analogous to the way in which email security operates. Email operates in a non-interactive fashion and, therefore, the security technologies developed for email are directly adaptable for use in the IPN.

How long before there is a "stable interplanetary backbone"?

Like terrestrial network backbones, an interplanetary backbone would be a set of high-capacity, high-availability links between network traffic hubs. The difference is that these network traffic hubs would in many cases be hundreds of millions of miles apart.

Obviously they wouldn't be connected by optical fiber, so we have to rethink just what we mean by "stable". Because all interplanetary data transmission will be wireless (either radio or, eventually, radiated laser light), the connections between traffic hubs could always be interrupted when planetary rotation or orbital motion takes a transmitting entity out of line-of-sight to the receiving entity.

However, NASA is already studying designs for a "Mars network" of multiple orbiting relay satellites. These satellites would be launched over a period of years, possibly starting in 2005, and the constellation would be replenished by new launches as older satellites' orbits decay. This would enable connectivity between Earth and Mars much (or even most) of the time. The frequent and relatively high-speed connectivity provided by the planned Mars network wouldn't be as "stable" from minute to minute as a terrestrial backbone.

By deploying it, though, NASA would for the first time establish a deep space infrastructure whose sole purpose is to support the communication needs of multiple missions into the indefinite future. That is, unlike the ad hoc deep space communication performed by individual exploration spacecraft, the link between the Deep Space Network on Earth and the Mars network would be "stable" from month to month and from year to year. This will probably be the first segment of the interplanetary backbone.

What missions will use the IPN?

Why use internet protocols in space?

Why are NEW protocols necessary?

Why not just use TCP/IP?

How far in the future are you looking?

When will the first instance of the IPN be launched?

Send your questions to mzukoski_at_mitre.org; while we cannot guarantee a personal response to all questions, we will try to answer them via this FAQ page!

Stay tuned!