Intertubes In Space
A few months back, NASA announced the successful testing of the first deep space network using a relatively new protocol (Disruption-Tolerant Networking). This was pretty cool in itself. Developing a new protocol especially one that is fault-tolerant at distances that are measured in light-minutes has to get your creative juices going.
I thought of this when I read about the Solar Dynamics Observatory finally getting a slot on an Atlas 5 launch package in October 2009. This new robot will enhance our understanding of our closest star, peering into its depths where the existing SOHO and TRACE observatories can not. The article mentions that SDO will download 1+ TB of data daily! That got me thinking about how they are going to transmit that data down to the the blue marble (and thus to the ramble at the beginning of this blog). Here is what I found on the SDO specs:
- The rapid cadence and continuous coverage required for SDO observations led to placing the satellite into an inclined geosynchronous orbit. This allows for a nearly-continuous, high-data-rate, contact with a single, dedicated, ground station.
- Nearly continuous observations of the Sun can be obtained from other orbits, such as low Earth orbit (LEO). If SDO were placed into an LEO it would be necessary to store large volumes of scientific data onboard until a downlink opportunity. The large data rate of SDO, along with the difficulties in managing a large on-board storage system, resulted in a requirement of continuous contact.
So the team is relying on an inclined geo orbit. The primary download station will be devoted dish antennas at White Sands, New Mexico. The mission is set to last for a minimum of five (5) years. 1TB per day = 90 Petabytes of data! Damn! I’d love to work on a system to mine that data!