For VLBI, increased data rates lead to increased sensitivity of observations and, for most types of observations, are the equivalent of building a physically larger antenna, but at a fraction of the cost. For geodetic-VLBI applications (in particular the NASA/GSFC-led VLBI2010 initiative), increased data rates enable more accurate station-position determinations (few-mm global accuracy in 3 dimensions) of geodetic stations in a coordinate system defined by distant quasars. Such precise measurements, in turn, allow highly accurate determination of the Earth’s wiggles and wobbles space, which in turn can be used to study the drivers of these motions, including atmospheric and ocean-current coupling to the solid Earth and motions of mass within the Earth’s interior.
For Astrophysical applications, increased data rates permit Radio Astronomers to increase the sensitivity of radio telescopes in order to observe fainter and more distant objects within our Universe. By using many stations during VLBI observations, detailed ultra-high-resolution (tens of micro-arcseconds) images of radio sources can be made that no other observation technique at any wavelength can achieve. One of the most interesting and intriguing objects that is currently being probed is the area near the presumed black hole at the center of our Galaxy, which subtends <~40 micro-arcseconds as viewed from Earth and is extremely faint. Observations of objects such as black holes, quasars and pulsars at these resolutions allow probing of fundamental concepts such as General Relativity and Dark Energy. Representing an improvement in sensitivity of nearly a factor of three over current data-capture capabilities, the Mark6 system is a key enabler of these Radio Astronomy science goals.
The VLBI application has been of great interest to the High-speed Research and Education networking community for a number of years. VLBI is distributed by nature, and can benefit from the high-speed transfer of petabytes of Radio Astronomy data across international multi-gigabit per second networks in real-time. By combining VLBI and networking, scientists are able to create a real-time distributed instrument that is capable of pushing the boundaries of high speed networking science in many directions. From a networking infrastructure point of view, VLBI poses interesting research challenges in both the data and control planes. From the network node point of view, VLBI can greatly benefit from research in the areas of high performance, high throughput COTS-based network attached storage and processing servers. The Mark6 system will leverage and operationalize existing GSFC HECN research in these areas. It will also form a transition platform for future GSFC HECN research in this area, as well providing a basis for conducting cutting edge research in the area of high performance electronic-VLBI experiments. These are experiments that will utilize next generation wide area networks to transfer VLBI data.
The Mark6 system is a practical system that is fulfilling a clearly identified operational need for VLBI 2010 operations. In addition to this, the Mark6 is benefiting from and contributing to research in both the Radio Astronomy and High-end computer networking science domains.