Extremely Loaded Grain (HLG) Stable Rocket Motors enable prolonged vary and customised thrust profiles with the identical propellant and the identical dimension rocket motor.
Anduril and Raytheon introduced on Oct. 7, 2025 they carried out a static fireplace take a look at of the previous’s Stable Rocket Motor (SRM) that includes a Extremely Loaded Grain (HLG) configuration. Anduril described the take a look at as a “main development in propulsion expertise for air-to-air weapons,” which comes amid each a broad push in propulsion programs for missiles, and the event of long-range missiles themselves to match those fielded by Russia and China.
Whereas Anduril designed and developed the HLG-configuration motor utilizing expertise from Naval Air Weapons Station China Lake, Raytheon’s Superior Expertise Staff “offered essential technical experience and oversight all through the event, design and execution phases of the take a look at.” Neither firm specified when the take a look at passed off.
This means Raytheon certifying the scale and dimensions of the HLG SRM, beside setting the anticipated efficiency standards like burn price and thrust wanted for air-to-air missiles. Each firms had been additionally below contract with the Air Pressure Analysis Laboratory Munitions Directorate.
Notably, Raytheon, a part of RTX, is the developer and producer of AIM-9 Sidewinder and AIM-120 AMRAAM sequence of missiles.
The HLG design was developed and constructed by Anduril utilizing expertise from Naval Air Weapons Station China Lake. The design allows considerably higher volumes of energetic propellant, delivering elevated particular impulse and enhanced motor efficiency. These enhancements…
— Anduril Industries (@anduriltech) October 7, 2025
JATM, energetics and propulsion programs analysis
Lockheed Martin has been creating the AIM-260 JATM (Joint Superior Tactical Missile), whose renderings up to now have steered it’s not an air-breathing system. HLG propellant expertise falls inside the ‘energetics’ space, which permits prolonged vary and customised thrust profiles with the identical propellant and the identical dimension rocket motor.
GE Aerospace additionally just lately shed extra gentle on its hypersonic propulsion packages, with the testing of a Stable Gasoline Ramjet (SFRJ) and a dual-mode rotation-detonation combustion ramjet (DMRJ). On Might 6, Colorado-based Ursa Main additionally introduced a number of static fires exams of a 5 inch stable rocket motor in a HLG configuration.
The U.S. was discovered to have lagged in energetics starting within the Nineties, with China having surged forward, owing to each a drop in a R&D expenditure and the Pentagon’s efforts to extend the accuracy of weapons, fairly than their vary or explosive pressure.
The Energetics Expertise Middle (ETC), a nonprofit analysis group that does work for the federal government, touched upon the problem in a now eliminated 2021 Pentagon-commissioned report. “It is a case the place we might probably be overwhelmed over the top with our personal expertise,” Bob Kavetsky, head of the Energetic Expertise Middle, instructed Forbes in Mar. 2023.
The take a look at
Anduril mentioned that the design examined “allows considerably higher volumes of energetic propellant, delivering elevated particular impulse and enhanced motor efficiency,” additional including “these enhancements translate immediately into prolonged vary and higher tactical benefit.” This additionally follows Anduril commissioning its full-scale $75 million SRM manufacturing facility in Mississippi that affords “the much-needed scale, resiliency, and innovation to allied SRM manufacturing.”
— Anduril Industries (@anduriltech) August 5, 2025
Raytheon, in the meantime, mentioned that the take a look at was part of a broader “response to the rising international demand for munitions,” for which the corporate has been “working with home and worldwide companions to boost U.S.-based rocket motor manufacturing capability.”
Anduril Industries’ senior vice chairman Lt. Gen. Neil Thurgood known as designing and firing a Extremely Loaded Grain rocket motor “one of the vital technically demanding duties within the stable rocket motor trade.” The take a look at demonstrates Anduril’s “potential to ship high-performance propulsion options in a website lengthy outlined by a small set of suppliers.”
Missile propulsion and Past Visible-Vary Warfare
We’re assuming the JATM goes to be a non-air-breathing engine, in contrast to the Meteor BVRAAM, primarily based on renditions printed on air pressure price range paperwork, which didn’t present air intakes. There isn’t a info but on the missile’s seeker, navigation, steering and propulsion configuration.
A working information of missile expertise fitted to beyond-visual ranges of over 300 km, particularly with versatile kill chains that may additionally maintain the launching plane secure, tells us that the munition will need to have an energetic radar seeker programmed to activate in its terminal stage. Within the post-launch and cruise section, the missile should be able to receiving mid-course steering information from both the launching jet or an exterior supply like an AEW&C plane by a two-way information hyperlink.
Exterior steering retains the service jet secure by permitting it to maintain its radar turned off in a heavy digital warfare jamming surroundings. An AEW&C plane is even safer, working farther away from the core battlespace. As for the propulsion system, a dual-pulse rocket motor that may fireplace a second time throughout its descent in direction of the goal, following the preliminary climb after launch, maintains the missile’s pace, velocity, kinetic power and thereby permits a shorter journey time to the goal.
Medium and long-range missiles, just like the AIM-120 AMRAAM, have been recognized to make the most of this ‘lofting’ method to enhance their vary. Upon launch, it climbs up in a parabolic arc into rarified air at excessive altitudes. The shortage of air resistance and little drag permits higher kinetic power, and a wider goal scan space with an energetic seeker when it begins descending.
