1.1 Proposal and Award History
ALPACA - Advanced L-band Phased Array Camera. Brigham Young University (BYU), in collaboration with Cornell University, is developing the Advanced L-band Phased Array Camera (ALPACA) that was to be a facility instrument on the Arecibo 305 m radio telescope prior to the collapse of the telescope on Dec. 1, 2020.
Figure: Collapse of the Arecibo Telescope in progress on Dec. 1, 2020. This was the original intended host for the ALPACA instrument. Image credit: National Science Foundation
The original proposal to fund ALPACA was submitted in February 2016 and was reviewed very favorably. However, NSF MSIP program officer Richard Barvainis notified us that a final decision fund would be deferred until a final disposition for the future of Areciobo Observatory was determined. The proposal was placed on hold for roughly two years until a path forward for AO was established with a 5-year transition period of declining NSF support. In June of 2018, NSF awarded funds for the development of ALPACA and the project began with the instrument targeted for Arecibo.
In late 2020, the ALPACA front end array antenna element design was complete, a mechanical design for the cryostat was underway, signal transport design and prototyping were in progress, and digital back end software was taking shape. At the time of the Arecibo collapse, the high level design of ALPACA was largely complete, and low level design and prototyping of major subsystems were well underway. After the collapse, discussions with GBO and NSF began with a view towards repurposing ALPACA for the GBT. Initial talks progressed from informal to increasingly formal over the ensuing months, leading to this PDR effort. Technical studies aimed at determining whether the ALPACA front end design and back end specifications were near optimal for the GBO were completed in late 2020 and early 2021 with positive and encouraging results.