Hey Dwight do you mind, if you can, listing some of the proposed features and capabilities of the future JDRADM missile? Thanks...

If they can fit those in the Raptor's weapons bay (which is almost certainly a requirement), no radar system would be safe!

I do not think that will be a challenge. The F-22's weapon bays hold three AMRAAMs each in a staggered fashion such that the fins of the missiles overlap those of the adjacent missiles. The AMRAAM is 7" in diameter with a 12.5" (actually 12.45") box section including fins. This means that the bays has room for ordnances at least 32" (2.75+7+2.75+7+2.75+7+2.75) across in total plus adequate clearances between multiple weapons.

More interesting will be a scenario where they end up increasing the diameter of the JDRADM beyond that of the AMRAAM They can do it as long as the box section of the new missile does not exceed about 10.6". With folding fins (ala ESSM) you can put three 10" missiles in the bay, each up to about 3.8 m long. A 10" JDRADM will have significantly increased range over the AMRAAM even without air breathing propulsion or radical lightening. It will also allow for a larger warhead yield which may be desirable if the missile is going to engage ground targets like SAM radars and the like. A 10" missile will be in the 600~700 lbs class (the ESSM is 620 lbs and it is only 10" 2/3 of the way with a 8" front section; the PAC-3 ERINT is a 10-incher which is 700 lbs but 5.2 m long). The F-22 will need a new ejector not the LAU-142/A. An F-35 will also require a beefier new ejector in the door position if it wants to carry it, the #4/8 "so called" A2G stations will have no problems however and it may in fact be easier to put two of 10" folding fin missiles on that position as no staggering is needed.

I wonder if they have considered just using ESSM as a starting point for JDRADM? Raytheon appears to be doing a significant portion of the work needed to mate the AMRAAM seeker to ESSM as part of the SL-AMRAAM-ER project. And as you've said, an ESSM should fit in the same space as an AMRAAM in the F-22's bays.

It would be a significantly heavier solution. This would prevent it from carriage on some AAM-only stations on various aircraft.

Not ideal definitely, but might be far less costly than designing a new missile largely from scratch. It would also give you a lot more room for the warhead and ARM sensor (especially if you went to 10" diameter all the way).

I wonder if they have considered just using ESSM as a starting point for JDRADM? Raytheon appears to be doing a significant portion of the work needed to mate the AMRAAM seeker to ESSM as part of the SL-AMRAAM-ER project.

It goes from zero speed, zero altitude to Mach 4.2 in under 10 seconds with a range of 50km from a surface launch.

where did you get this info?

The ESSM is a SAM. It is by definition launched from a zero-zero conidition.

Given that its #1 role is as an AShM interceptor, at 10 seconds it'll be at roughly 6~10km from the ship. It will make sense for the missile to reach its maximum velocity before that. All-boost motors also tend to expend their grain in <10 seconds.

Astronautix gave it's performance is given as Mach 4+ with a range of 27+ nm, citing the following sources:-

"World Naval Weapons Systems, 1997/98", Naval Institute Press, 1997
"Vision... Presence... Power, A Program Guide to The U.S. Navy", 2000 Edition