How's good ESSM compare to ASTER.......?[
The article has already answered your question.
It is understood that while ESSM formed part of the original
technical and commercial baseline presented to the RMN by BAE
Systems, the customer subsequently endorsed Aster 15 as its
preferred technical option after conducting its own performance
evaluation and scenario modelling.
However, due to costs, it was dropped;
However, the increased acquisition and integration costs
associated with Aster 15 pushed the overall price of the frigate
programme significantly above the RMN's budget ceiling.
Since both the RSN and RMN wanted the Asters after the
respective peformance evaluations, it just goes to show which
missile is the preferred one.
The maximum range of the ESSMs is never officially stated but
construed at between 15 to 50km since the designers said the
maximum range has been increased by more than twice. The original
Sea-sparrow had several versions as well with different ranges with
the longest ranged one being carried by Aegis ships and most
probably due to the Aegis radar/illumunators.
And the purported maximum range of 50 km refers to RIM-162A which
are equipped on Aegis-based ships after taking the maximum range
possible given to a Sea-sparrow missile by defence enthusiasts.
Most would agree that the effective range is much shorter. In
addition, the RIM-162B/Cs are the ones which the article mentions
and found on non-Aegis based ships.
The effective
range of the Aster 15 is 30 km. That does not mean it cannnot fly
further than that at maximum range.
At any rate, you just can`t compare missiles per se. Ship on-board
systems which support the weapons matter as much. But it
says as much when the RMN wanted to get the Asters but could not
due to costs.
My guess is that the Asters and ESSMs are more or less similar at
actual effective range but the Asters are probably better at
agility and its ability at responding to saturation attacks. The
Asters are also less constrained by radar types and illuminators
which the latter does not require as compared to the ESSM. Hence,
more Asters can be launched at targets repeatedly and minimally
controlled simualtaneously in the air. The formidable can launch
and control as many 10-16 Asters at one time. (And the Formidables
carry 32 of them with the capacity to carry more with future block
upgardes which the RSN does frequently with all her ships. Check
out the Victory class corvettes and compare the specification when
she was first commisioned in the early 1990s.)
The number of ESSMs in flight, however, is dependant on the number
of illuminators(and locations on ship in some cases) to provide
end-game guidance and a good radar to guide them like the Aegis
system.
The Asters are also newer. Conversely, the ESSMs are actually
upgrades over the older Sea-sparrows.
I see this report as being similar to the report about Malaysia
being poised to buy the Super Hornets, Rooikvalks, etc. Recently,
there was a another report stating that the RMAF is poised to buy
the Super Hornets among a whole slew of similar reports over the
years. Needless to say, there is more news than the actual stuffs
coming out from up north.
We really ought to wait till they build the ships and really
commission them. ESSM is an American weapon. Let the negotiations
and approval processes (all the way to the American Congress)
begin.. 
Dont be surprised the two frigates
materialise next decade and dont be surprised they come with Asters
in the end since they found the Americans rather uncooperative or
that they come with too much strings attached. It may even come
with the old Sea-wolfs or Micas(more likely since costs matter a
lot to them).
And they have done it again. They are thinking of buying another
system. Sea-wolfs are British. ESSMs are American. They have
another system on board the Laksamana corvettes as well. It`s like
going shopping. Must taste a bit of everything. How on earth will
they tie all those equipment together where command and control and
over-all system integration is concerned ? Maybe by simple radio.
They have a long way to go where network-centric warfare is
concerned and these purchases would not help at all.