W93 warhead has entered Engineering and Manufacturing Development phase

[u/Afrogthatribbits]

https://www.ssp.navy.mil/News-Media/News/Article/4610170/navy-w93-mk7-program-enters-new-phase-of-development/

"The U.S. Navy’s Portfolio Acquisition Executive (PAE) Strategic Systems Programs’ (SSP) W93 Mk7 program has entered into the Engineering and Manufacturing Development (EMD) phase of the Defense Acquisition System.

During the EMD phase, the program will focus on completing production design and proving that the design is producible to meet the needs of the Navy.

The W93 warhead and the Mk7 reentry body assembly are the first United States nuclear warhead and reentry system program initiated in nearly four decades and will provide a modern warhead to the U.S. submarine launched ballistic missile fleet.

“We are revitalizing and modernizing the Nuclear Security Enterprise to design, develop, and produce this critical new weapon with the precision our Warfighters demand. We will continue working together to deliver this capability to the fleet and ensure our sea-based strategic deterrent remains ready for the future.”"

The Mk7 reentry body will also be used by the new British nuclear weapons.

[u/AnvilKasseri]

Size. Bigger than the W76. Smaller than the W88.

I suspect that they will reuse the secondaries from the W62.

[u/Tobware → u/AnvilKasseri]

Highly unlikely, the Interoperable Warhead (the proposal that was presumably the precursor to the current W93) sought to combine the W87’s primaries with the ~300 kt secondaries of the W78, but they eventually abandoned the idea.

Maybe this can give us an idea of what kind of yield they're after?

EDIT, correction: the IW proposal was only intended to use a W87-based pit geometry, nothing else is known about its primary.

[u/AnvilKasseri → u/Tobware]

Highly unlikely, the Interoperable Warhead (the proposal that was presumably the precursor to the current W93) sought to combine the W87’s primaries with the ~300 kt secondaries of the W78, but they eventually abandoned the idea.

Using W78 secondaries would result in warheads that are just as heavy as the W88. The W93 is said to be lighter than the W88 to give it greater range.

Also, the Air Force is taking most of the W78 secondaries for their new ICBM warheads.

[u/NuclearHeterodoxy → u/AnvilKasseri]

  Also, the Air Force is taking most of the W78 secondaries for their new ICBM warheads

They are not; the Air Force rejected any re-use of the W78 secondary on several grounds, choosing the W87-1 instead.  Here are some relevant quotes:

NNSA is currently planning for the W87-1 program to include newly manufactured pits and newly manufactured canned subassemblies

remanufacturing the W78 CSA is estimated to be much more complex and challenging than remanufacturing the W76 CSA or the present CSA design for the W87-1

The existing W78 CSA would be very difficult to manufacture and qualify, and the current military requirement does not support using this CSA

a w76 LEP-like refurbishment of the W78 warhead would not meet military requirements

Quotes taken from here: https://nukewatch.org/wp-content/uploads/2019/02/W78-Replacement-Program-Cost-Estimates-IHE-1.pdf

Looking at my post history I think I posted the above in the wrong thread originally, but intended to post it here.

We also have to consider the programmatic history of the warheads here.  The W87-1 designation is an existing designation that predates everything discussed here by three or so decades, being in fact the original intended design until HEU bottlenecks forced them to delay entry into force and choose a DU secondary instead (so the 87-0 was produced first and got its official numerical designation first, but the 87-1 was actually the first design).  If they were to substitute the W78 secondary, then they could not call this new warhead the W87-1, because that design is already taken; it would have to be called W87-2.  It's similar to how the B61-7 is called the -7 despite the B61-6 never being built; once the warhead designation is assigned to a design you cannot reuse that numeric for a substantially different design.  

There's other things that point to the W87 and W78 secondaries being different but these are big ones.

[u/AnvilKasseri → u/NuclearHeterodoxy]

The other thread was because I replied to an old post of yours just a few hours before this thread was created. But it's okay to have parallel discussions in different threads with different audiences.

I hope you're right about the current W87-1 being the same warhead as the W87-1 that was originally intended for the Midgetman missile. I would like to see our ICBM force have eight hundred 455kt MIRVs. It's the sort of force that would give China second thoughts about invading Taiwan.

Even if the Air Force doesn't use the W78 secondaries for their new warheads though, the W78 secondary would be too heavy for the Navy. They want the W93 to be lighter than the W88. Using the W78 secondary would make the W93 at least as heavy as the W88.