In the late 1960s, the Space General Division of Aerojet General Corp. designed the Kangaroo rocket. This was a meteorological sounding rocket of the "boosted dart" type, where the dart was nested inside the propellant bore of the booster rocket.
Historical Essay © Andreas Parsch
Aerojet-UTC PWN-9 Kangaroo
In the late 1960s, the Space General Division of Aerojet General Corp. designed the Kangaroo rocket. This was a meteorological sounding rocket of the "boosted dart" type, where the dart was nested inside the propellant bore of the booster rocket. This made the Kangaroo significantly shorter than the contemporary Loki-Dart type rockets (see RM-82-PWN-1, RM-88-PWN-5 and PWN-8) where the dart was mounted on top of the booster. The Kangaroo booster's diameter was to be around 10 to 15 cm (4 to 6 in). A pyrotechnic charge in the base of the dart was to push it through the motor casing after rocket burnout. The booster's nose cap was to be built of a special glass, which had a high structural strength but would shatter in tiny pieces when hit at the center point.
The U.S. Navy's Naval Surface Weapons Center at Oxnard became interested in the Kangaroo design, and in July 1968, the designation XPWN-9A was reserved for the projected sounding rocket. However, there was very little development funding available, and the Navy requested competitive bids from the industry. Aerojet's proposal was underbid by the Chemical Systems Division of UTC (United Technology Corp), and UTC got the contract although their proposal was judged inferior in the technical aspect. UTC's dart ejection design was different from Aerojet's and didn't use the special glass head cap on the booster.
The XPWN-9A booster was eventually flight-tested, but the tests were reportedly not successful (possibly because of pitch-roll coupling difficulties). In the end no operational Kangaroo sounding rockets were built.Specifications
I have no information about the physical characteristics of the XPWN-9A.Main Sources
 E-mail from Dan Meyer
 Department of Defense Missile Nomenclature Records
Status: Cancelled 1969.