The SteelNavy.Com Message Board: Re: S/X Band radars on DDG timeline

The key to your answer is to read the details of the CGX program, which cancelled in 2011.

This link should (I so very much hope) let you download a pdf of the 2011 Congressional report on CGX:

https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.congress.gov/crs_external_products/RL/PDF/RL34179/RL34179.35.pdf&ved=2ahUKEwihjO6Oxf2VAxXUrYkEHUxIOfwQFnoECFsQAQ&usg=AOvVaw29uCm86_KNYSL49NSdYmvj

Within it is this paragraph:

"The Navy’s desire to cancel the CG(X) and instead procure Flight III DDG-51s apparently took
shape during 2009: at a June 16, 2009, hearing before the Seapower Subcommittee of the Senate
Armed Services Committee, the Navy testified that it was conducting a study on destroyer
procurement options for FY2012 and beyond that was examining design options based on either
the DDG-51 or DDG-1000 hull form.20 A January 2009 memorandum from the Department of
Defense acquisition executive had called for such a study.21 In September and November 2009, it
was reported that the Navy’s study was examining how future requirements for AAW and BMD
operations might be met by a DDG-51 or DDG-1000 hull equipped with a new radar.22 On
December 7, 2009, it was reported that the Navy wanted to cancel its planned CG(X) cruiser and
instead procure an improved version of the DDG-51.23 In addition to being concerned about the
projected high cost and immature technologies of the CG(X),24 the Navy reportedly had
concluded that it does not need a surface combatant with a version of the AMDR as large and
capable as the one envisaged for the CG(X) to adequately perform projected AAW and BMD
missions, because the Navy will be able to augment data collected by surface combatant radars
with data collected by space-based sensors. The Navy reportedly concluded that using data
collected by other sensors would permit projected AAW and BMD missions to be performed
adequately with a radar smaller enough to be fitted onto the DDG-51.25 Reports suggested that the
new smaller radar would be a scaled-down version of the AMDR originally intended for the
CG(X).26"

So, while the Zumwalt destroyer itself was canceled, consideration of the hull was still ongoing for a short period after. Until the Navy realized Flight III was possible, it was still locked into the DDG-1000 hull, and frantically studying how to get out of that. Once it found it could, Congress finally terminated the CGX program, hull and all in 2011.

Previous Message

That is a convincing explanation.

I have a question about the timeline:
On 31 July 2008, the Navy requested that the procurement of additional Zumwalts be stopped, and that construction of the Arleigh Burke class (Flight IIA Restart variant) be restarted instead.

I found that development of the SPY-6 radar began in June 2009, and that the decision to develop the Flight III variant was made in 2009/10.

That would be AFTER the Zumwalt class was restricted to two and then three ships (which caused a cost explosion also for the SPY-3 and SPY-4).

The first SPQ-9B for an Arleigh Burke class destroyer was possibly ordered in November 2013.