Modern Naval Vessels

[weasel1962]

DF-17.

[boogieman]

DF-17.

Ah yes, I was under the impression that it was an ICBM but I was incorrect. The larger question is whether the WU-14 HGV could be used to target moving naval vessels. Could be a big problem if so.

That said it seems that the effort to develop an anti-ship HGV is still in progress, with RGPWS and HDWS also underway as potential counters. The arms race continues...

[marauder2048]

That's interesting, was not aware of that. The question then becomes one of whether SM3 has the range to catch the ASBM in its mid-course phase/before it ducks too low to be engaged. The (much) greater reach of SM3 Blk II (A&B) may be useful here.

The SM-3's "official range is ~2500km, so an ASBM would have to shed its booster, and and begin a steep descent, to stay out of range. Of course the SM-6 is an endo-atmospheric interceptor, so it could take over once a threat reentered the atmosphere.

You would take a range hit but given that the Chinese have flown almost all of their recent MRBM/IRBM/ICBMs
on depressed trajectories it seems likely they would do so in anger. There are other tradeoffs like increased
thermal load on the MaRV (if exposed) and potentially less time for the MaRV's seekers to find the carriers.

But you wouldn't have to exceed 100 km in altitude and still get out to 1600 nautical miles. That would under-fly SM-3.
But SM-6 would still be useful. I suspect it's this reason (amongst others) that's motivating SM-6 Block IB rather
than improvements to SM-3 like the Block IIB.

[weasel1962]

Test altitudes were ~60km. At that altitude, sea level radar horizon is ~1000km (550nm) which at mach 5 ingress would provide ~10 minutes reaction time (5min at mach 10). Airborne AWACS (with CEC) would double that.

No moving target capability can still be a threat e.g. docked CVNs at Japan and Guam. Guam is 1600nm from the coast of China.

[weasel1962]

For avoidance of doubt on the target sets. Apparently the last DF17 test was a few days back on June 13.

https://twitter.com/rajfortyseven/statu ... 45/photo/2

[boogieman]

Thanks for the context. Clearly the capability to kill HGVs and HCMs will be needed in due course. For now it seems we may be limited to disrupting the kill chain in other ways (e.g. soft kill, dismantling ISR apparatus). This obviously isn't ideal, as targeting ISR assets on mainland China may well elicit unwanted (cref nuclear) escalation.

[wrightwing]

For avoidance of doubt on the target sets. Apparently the last DF17 test was a few days back on June 13.

https://twitter.com/rajfortyseven/statu ... 45/photo/2

It's one thing for them to practice against stationary known targets, but I'd love to hear about tests where they had to find and engage unknown targets, that were moving and manuevering.

[marauder2048]

For avoidance of doubt on the target sets. Apparently the last DF17 test was a few days back on June 13.

https://twitter.com/rajfortyseven/statu ... 45/photo/2

It's one thing for them to practice against stationary known targets, but I'd love to hear about tests where they had to find and engage unknown targets, that was moving and manuevering.

Maybe it's one of those things where they don't demonstrate it against a moving target because
if a demo failed it would damage the credibility of the weapon.

But at the moment, the defense would have to honor the possibly that it (and the kill chain behind it)
can hit moving/maneuvering targets

[boogieman]

For avoidance of doubt on the target sets. Apparently the last DF17 test was a few days back on June 13.

https://twitter.com/rajfortyseven/statu ... 45/photo/2

It's one thing for them to practice against stationary known targets, but I'd love to hear about tests where they had to find and engage unknown targets, that was moving and manuevering.

The thing that has me curious is how they get around the disruption of onboard seekers caused by the hypersonic plasma sheath. Presumably you'd need an RF based terminal seeker to hit a moving target, but the technical challenge involved in making this work strikes me as significant. Even if you could get around it I do wonder if there would be a residual vulnerability to jamming/spoofing etc.

[marauder2048]

For avoidance of doubt on the target sets. Apparently the last DF17 test was a few days back on June 13.

https://twitter.com/rajfortyseven/statu ... 45/photo/2

It's one thing for them to practice against stationary known targets, but I'd love to hear about tests where they had to find and engage unknown targets, that was moving and manuevering.

The thing that has me curious is how they get around the disruption of onboard seekers caused by the hypersonic plasma sheath. Presumably you'd need an RF based terminal seeker to hit a moving target, but the technical challenge involved in making this work strikes me as significant. Even if you could get around it I do wonder if there would be a residual vulnerability to jamming/spoofing etc.

It's really a non-issue for typical RF seeker frequencies at typical IRBM HGV/MaRV velocities;
lower-frequency datalink and GNSS signals...maybe.

[boogieman]

It's really a non-issue for typical RF seeker frequencies at typical IRBM HGV/MaRV velocities;
lower-frequency datalink and GNSS signals...maybe.

Interesting. Where'd you hear that?

[marauder2048]

It's really a non-issue for typical RF seeker frequencies at typical IRBM HGV/MaRV velocities;
lower-frequency datalink and GNSS signals...maybe.

Interesting. Where'd you hear that?

It's really a non-issue for typical RF seeker frequencies at typical IRBM HGV/MaRV velocities;
lower-frequency datalink and GNSS signals...maybe.

Interesting. Where'd you hear that?

It's been in DOD/USG publications on the matter for many years.
And recently reiterated by Mike White, assistant director of hypersonics with the Pentagon.

When we fly a missile for sustained hypersonic flight within the atmosphere, the plasma tends to not be so much of a problem,” he says. “We see plasma effects when we have relatively blunt bodies entering from space and the velocities they’re very, very high, and the shockwaves are very, very strong, so that heats the air even more severely than what we experienced in sustained flight.”

"Time Critical Conventional Strike From Strategic Standoff" is a good reference.

[boogieman]

Awesome, thanks for the source

[boogieman]

An interesting piece on emerging tech that may be relevant to countering the HGV/HCM threat in due course:

https://assets.documentcloud.org/docume ... Guided.pdf

I had thought that EMRG or derivatives thereof might yield something useful in this space but progress seems to have stalled as best as I can tell(?). I have read comments elsewhere suggesting that railguns present significant challenges with barrel wear and the electromagnetic environment generated inside the chamber interfering with guidance systems onboard the weapon's rounds. Anyone able to shed more light on this?

[marauder2048]

An interesting piece on emerging tech that may be relevant to countering the HGV/HCM threat in due course:

https://assets.documentcloud.org/docume ... Guided.pdf

I had thought that EMRG or derivatives thereof might yield something useful in this space but progress seems to have stalled as best as I can tell(?). I have read comments elsewhere suggesting that railguns present significant challenges with barrel wear and the electromagnetic environment generated inside the chamber interfering with guidance systems onboard the weapon's rounds. Anyone able to shed more light on this?

A 32 MJ railgun with a useful rate of fire (say 10 shot per minute) will require 17 MW of ship power
and will induce a cooling load of 10 MW. There's nothing in the US fleet aside from (maybe) three Zumwalts
or the Ford class that would come close to being able to accommodate those loads.