I hope it works.
This press release describes the new 500-mile range variant which compares it to the 200-mile range original variant.
JASSM is sub-sonic and since there aren't any videos of it doing nap-of-the-earth flight profiles, it is possible that it depends only on stealth to survive.
That could be challenging. First day of duck season.
Also mentioned by the USAF is its over-optimism with GPS assistance to the inertial navigation (INS) in the missile. GPS is great for the JDAM which has a short flight time (around 1 minute). If the jet dropping JDAM already has a tight INS fix (better if enhanced by a radar update), the JDAM's INS is going to hit--GPS or no.
The longer range you shoot the more updates you need. GPS degradation is mentioned by the USAF but if it is a long range shot and GPS is denied, good luck hitting much. This comment doesn't hold water:
"Even without GPS, the JASSM can find its target due to its internal sensor."
Also, if they are depending on net-enabled updates, that can be geo-located and/or denied.
What would help? Celestial navigation. The B-2 has a very accurate celestial navigation unit in its left wing. Some old Cold War ideas had an analog ones...but accuracy only needed to be good enough for nukes.
How did pre-GPS cruise missiles like ALCM off of the B-52 do it? With a terrain contour-matching guidance system (SAC SIOP=highly scripted missions) and again nukes needing less accuracy. Survivablity was based on flying nap-of-the-earth around known threats.
Bomb damage assessment (BDA) of Desert Storm targets hit with ALCM's converted from nuke to conventional warheads, with this technology of the day was mixed; and, over-hyped. Or as General Powell put it: something about bouncing rubble with million-dollar missiles; for those those that made it near the proper target.
Post-Desert Storm, ALCMs were upgraded with GPS assist.
How the JASSM acts in real combat against high-end threats will be interesting. I hope we never have to find out. Scripted range events and all that. It beats the over-sell by the F-35 Joint Strike Fighter crowd claiming high-end IADS survival which doesn't exist.
The F-35 problem is that it is too weak to take on high end-IADS and too expensive to operate for any other kind of lesser threat. Unusable for the Pacific. Current legacy aircraft that can carry JASSM have a better shot at taking care of high and low threats.
JASSM was supposed to be an "affordable" cruise missile in the $400,000 each region. What the U.S. pays for each weapon these days isn't anywhere close to that.
So, cruise missiles are it. We are out of money and any real air power advocates are retired, dead, or doing anything else.
And, I wonder, why the USAF thinks 1763 F-35 Joint Strike Fighters, still makes any sense.