Near Earth Application of Delay/Disruption Tolerant Networking in Operational Networks

There are many scenarios in spacecraft communications where the need for DTN is evident.  Some of these include, but not limited to (1) Intermittent Connectivity (2) long or variable delay (3) asymmetric data rates (4) high communication error rates.  .  A combination of DTN and another technology called User Initiated Services (UIS) would move NASA networks toward this overtly seamless communication scheme seen in the cell phone industry and internet communication and ensure NASA leadership in that futuristic, but yet common approach. 

The return on investment is clearly evident with the use of DTN in the NASA communication networks. 

Current missions and future missions have increased the cost burden of ground communication links by pushing for near error free links.  These “error-free” links are needed in the absence of automated confirmation of data delivery from the spacecraft.  After a pass, if it is determined by the Mission Operations Center (MOC) or Science Operations Center (SOC) that not all the data was received, a command will be sent to the spacecraft on the next pass to retransmit the entire data set.  Clearly not the most efficient way of transporting data.  This would almost be equivalent to sending the same email multiple times a day because there is no way to be sure it would actually arrive at its destination.  Millions of dollars (at Goddard alone) are spent to provide significant overhead into communication links to reduce the likelihood of retransmissions.  An operational DTN implementation could greatly reduce this cost by automating confirmation of data delivery, where retransmission occur in realtime and can even be directed from a remote location (e.g. SOC or MOC).