My company builds high-speed data recorders (for examples of similar
devices see http://www.vmetro.com/real-time_recorders/real-time_recorders.htm,
http://www.wideband-sys.com/products.htm,
http://www.ics-ltd.com/info/ProductCat.cfm?ID=11). 

We play predominately in the aerospace and defense markets where
deterministic (real-time) performance, high bandwidth, and
low-latencies are all important; however we would like to expand into
other verticals.  We have been looking at the market associated with
space-based telemetry and data acquisition.  In this market typically
a ground station receives data (could be environmental telemetry data
or data relating to the applications mission such as radar, or
infrared) which is then recorded for later processing.  Companies that
sell data recorders into this space include L3, General Dynamics
(Through their purchase of Veridian), RT Logic, Apogee Labs, Heim Data
Systems and Sypris Data Systems.  The questions:

What is the data recorder opportunity (I am looking for market size in
dollars or units) for space-related applications?  For example I would
expect data recorders to be needed to record telemetry data, as well
as to record data related to satellite sensor systems (Ground mapping
RADAR, weather info, etc). Note this information may not exist
directly, but may be derivable from the annual reports of
participating companies.

What key features and capabilities are required for a data recorder to
do well in these type applications?

By the way, any interesting info you find out along the way about
potential competitors involving market share, or unique capabilities
would be useful and worth a good tip.