The SM-3 block IA version provides an incremental upgrade to improve reliability and maintainability at a reduced cost.

The SM-3 block IB, due in 2010, offers upgrades which include an advanced two-color infrared seeker, and a 10-thruster solid throttling divert and attitude control system (TDACS/SDACS) on the kill vehicle to give it improved capability against maneuvering ballistic missiles or warheads.
Solid TDACS is a joint Raytheon/Aerojet project, but Boeing supplies some components of the kinetic warhead.
With block IB and associated ship-based upgrades, the Navy gains the ability to defend against medium range missiles and some Intermediate Range Ballistic Missiles.

SM-3 block II will widen the missile body to 21 in and decrease the size of the maneuvering fins.
It will still fit in Mk41 vertical launch systems, and the missile will be faster and have longer range.

The SM-3 block IIA is a joint Raytheon/Mitsubishi Heavy Industries project, block IIA will add a larger diameter kill vehicle that is more maneuverable, and carries another sensor/ discrimination upgrade.
It was scheduled to debut around 2015, whereupon the Navy will have a weapon that can engage some intercontinental ballistic missiles.

Table sources, reference material:
A further SM-3 block IIB was "conceived for fielding in Europe around 2022".
In March 2013, Defense Secretary Chuck Hagel announced that the development program of the SM-3 block IIB, also known as the "next generation AEGIS missile" (NGAM), was undergoing restructuring.
Under Secretary James N. Miller was quoted saying that "We no longer intend to add them [SM-3 block IIB] to the mix, but we'll continue to have the same number of deployed interceptors in Poland that will provide coverage for all of NATO in Europe", explaining that Poland is scheduled instead for the deployment of "about 24 SM-3 IIA interceptors – same timeline, same footprint of U.S. forces to support that."
A US defense official was quoted saying that "The SM3 IIB phase four interceptors that we are now not going to pursue never existed other than on Power Points; it was a design objective."
Daniel Nexon connected the backpedaling of the administration on the block IIB development with pre-election promises made by Obama to Dmitry Medvedev.
Pentagon spokesman George E. Little denied however that Russian objections played any part in the decision.
The SM-3 block IA version provides an incremental upgrade to improve reliability and maintainability at a reduced cost.
The SM-3 block IB, due in 2010, offers upgrades which include an advanced two-color infrared seeker, and a 10-thruster solid throttling divert and attitude control system (TDACS/SDACS) on the kill vehicle to give it improved capability against maneuvering ballistic missiles or warheads. Solid TDACS is a joint Raytheon/Aerojet project, but Boeing supplies some components of the kinetic warhead. With block IB and associated ship-based upgrades, the Navy gains the ability to defend against medium range missiles and some Intermediate Range Ballistic Missiles.
SM-3 block II will widen the missile body to 21 in and decrease the size of the maneuvering fins. It will still fit in Mk41 vertical launch systems, and the missile will be faster and have longer range.
The SM-3 block IIA is a joint Raytheon/Mitsubishi Heavy Industries project, block IIA will add a larger diameter kill vehicle that is more maneuverable, and carries another sensor/ discrimination upgrade. It was scheduled to debut around 2015, whereupon the Navy will have a weapon that can engage some intercontinental ballistic missiles.
Table sources, reference material:
A further SM-3 block IIB was "conceived for fielding in Europe around 2022". In March 2013, Defense Secretary Chuck Hagel announced that the development program of the SM-3 block IIB, also known as the "next generation AEGIS missile" (NGAM), was undergoing restructuring. Under Secretary James N. Miller was quoted saying that "We no longer intend to add them [SM-3 block IIB] to the mix, but we'll continue to have the same number of deployed interceptors in Poland that will provide coverage for all of NATO in Europe", explaining that Poland is scheduled instead for the deployment of "about 24 SM-3 IIA interceptors – same timeline, same footprint of U.S. forces to support that." A US defense official was quoted saying that "The SM3 IIB phase four interceptors that we are now not going to pursue never existed other than on Power Points; it was a design objective." Daniel Nexon connected the backpedaling of the administration on the block IIB development with pre-election promises made by Obama to Dmitry Medvedev. Pentagon spokesman George E. Little denied however that Russian objections played any part in the decision.
RIM-161 Standard Missile 3