I'm assuming that it's not going to be much different in size than JASSM-ER, & I think that's a pretty safe assumption. If it's going to carry a decent sized warhead at least 500 nautical miles (the officially stated range), it has to be a similar size. It still beats NSM though and comes with a much bigger warhead. It doesn't appear thought to outrange some of the opposing systems out there which was one of the objectives at program inception.
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LM has pretty much disabused the perception that since LRASM is based on JASSM-ER it will have a similar range range. Here's an excerpt from an article in Air Force Magazine that I came across on another forum. All the additional sensors and electronics have necessitated a reduced fuel load.
AirSea Battle Weapon?
AirSea Battle Weapon?: Lockheed Martin hopes to get on contract with the Navy in 2014 for a derivative of its Joint Air-to-Surface Standoff Missile and JASSM-Extended Range system called the Long-Range Anti-Ship Missile, according to Dick Tate, the company's program manager for the new weapon. Developed as a DARPA project, LRASM has "the same mold line" and thus about the same stealth as the JASSM-ER, but replaces some of that weapon's internal fuel with avionics that permit man-in-the-loop "multimode" terminal guidance, said Tate last week at AFA's Air Warfare Symposium in Orlando, Fla. The sensors are designed to give the weapon capability against moving sea targets or mobile land targets. The JASSM-ER can go more than 500 miles, but
LRASM would have close to the baseline JASSM's range of more than 200 miles, said Tate. LRASM has a 1000-pound warhead and is meant for launch from aircraft like F/A-18E/Fs or B-1Bs, or from shipboard vertical launch system tubes with an ASROC rocket boosting it. Lockheed Martin said it successfully tested the system pushing through a VLS tube cover and the nose-mounted apertures were unaffected. The company also has conducted captive carriage flight testing of the LRASM sensor suite. The weapon would have about 85 percent commonality with JASSM-ER and would be built on the same production line in Alabama, according to the company.