Several different proposal submission mechanisms are used to propose observations on the various VLBI arrays itemized in Section 17.1. Appropriate links are provided in the Call for Proposals.
Proposals requesting more than 200 hours of total time on the VLBA, the HSA, or various combinations of NRAO telescopes in VLBI and non-VLBI modes, are covered under the NRAO Large Proposal Policy described at http://www.nrao.edu/admin/do/largeprop.shtml .
Some VLBA proposals may fall under the category of Rapid Response Science. This includes proposals for Known Transient Phenomena, Exploratory Time, or Targets of Opportunity. All must make use of the standard proposal formats, and proposals for Known Transient Phenomena must adhere to the normal proposal deadlines. Further details about Rapid Response Science are at http://www.vla.nrao.edu/astro/prop/rapid/ .