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xii FOREWORD The chapter on millimeter wavelength (mm) astronomy is not just a summary of NRAO’s involvement in mm astronomy, a field which was opened up and led by the USA, but an overview of all international mm astronomy efforts. The radio astronomy millimeter field developed in a very different way compared to the meter and centimeter wavelength astronomy. In the beginning millimeter wave receivers were bolometers with no spectroscopic capability and with poor sensitivity. As a result, there was a very limited scientific case with few observable sources, so the NRAO 36 foot at Tucson was a high-risk exploratory development. But with the unexpected discoveries of a plethora of spectral lines, millimeter radio astronomy became one of the hottest topics in radio astronomy, leading eventually to the billion-dollar ALMA project.

The book includes a great sequence of stories about building big telescopes for radio astronomy. These are all linked to NRAO, but reach well beyond NRAO as a result of NRAO’s strong influence on developments in radio astronomy throughout the world.

The authors analyze in some detail the actual US funding process for a number of major proposals: 140 foot, VLA, VLBA, GBT, and ALMA. In particular, one author (KIK) was directly involved in the VLBA proposal and associated funding process. These actual situations illustrate the difference between the simplistic notions of proposal, review, and funding decision, with the real-life process. This chapter on the VLBA is not just a part of NRAO history but a great historical overview of all VLBI developments by an expert who lived through this era. VLBI experiments, especially those involving space missions, are among the most complex international projects that ever succeeded, involving different institutes, countries, and science agencies. These firsthand stories provide exceptional examples of successful scientific collaboration. Kellermann recounts his involvement in a VLBI collaboration with Russia in the peak of the Cold War.

The Sugar Grove 600 foot radio telescope, referred to by Harvard radio astronomer Edward Lilley as “a radio telescope fiasco,” is also included. It is a story about a classified defense telescope being built near the Green Bank Observatory that has not been told before.

To maintain its viability through the period of traumatic delays in the construction of the 140 Foot dish, NRAO built a simpler, inexpensive 300 Foot transit antenna. At this time this 300 Foot Radio Telescope was one of the most powerful radio telescopes in the world and became an immediate success. For the first time, NRAO had a world-class instrument that was attractive to both visitors and NRAO staff. The successful completion of the 300 Foot transit radio telescope probably saved Green Bank from a premature closing resulting from the continued debacle with the 140 Foot antenna project. From the start of 300 Foot observations, the observatory operated as the first true visitor facility for radio astronomy.

But the 300 Foot story does not stop there. In 1988, NSF planned that the 27-year-old NRAO 300 Foot transit telescope be closed in order to provide funds for operating other new astronomical facilities. But when the 300 Foot