Length 7.9 m. (26 ft.); Cajun, 4.1 m. (13.5 ft.) Diameter 41.9 cm. (16.5 in.) max; Cajun, 17.1 cm. (6.75 in.) Propellant Solid Thrust Sustainer, 4364 kg. (9620 lb.) Velocity 6760 km./ hr. (4200 mi./hr.) Altitude 161 km. (100 mi.) with a 23 kg. (50 lb.) instrument package; higher with a lighter payload ARCAS [Illustration: 27. Loading ARCAS into launcher.] All-purpose Rocket for Collecting Atmospheric Sounding (ARCAS) gathers local meteorological data helpful to weather forecasters. Its 5.4-kilogram (12-pound) payload may include instruments which measure temperature, pressure, humidity, wind velocity and direction, and magnetic conditions. The single-stage ARCAS vehicle reaches an altitude of 64 kilometers (40 miles), propelled by a slow-burning solid-fuel engine which produces 141.4 kilograms (312 pounds) of thrust. When the ARCAS is boosted by a Sparrow or Sidewinder missile engine, it can reach altitudes of 182,880 meters (600,000 feet). The 32-kilogram (71-pound) ARCAS is far less expensive than the larger two-stage weather rockets it has replaced. It was developed and produced by the Atlantic Research Corporation. The ARCAS is from the Atlantic Research Corporation. Length 2.1 m. (7 ft.) Diameter 11.3 cm. (4.45 in.) Propellant Solid Thrust 159 kg. (350 lb.) Velocity 3590 km./hr. (2230 mi./hr.) Altitude 64 km. (40 mi.) with standard 5.4-kg. (12-lb.) payload; 91.7 km. (57 mi.) with a 2.3-kg. (5-lb.) instrument package Cricket [Illustration: 28. Preparing Cricket for launch.] The reusable Cricket, often called the “meteorologist’s handyman,” weighs only 2.5 kilograms (5½ pounds), 1.4 kilograms (3 pounds) of which is propellant. Recovered by parachute after each flight, Cricket costs less than $10 to refuel. The Cricket’s .34-kilogram (three-fourth pound) instrument package zooms to 975 meters (3200 feet) in only 12 seconds, gathering data on air temperature, pressure and wind direction. One of the rocket’s most noteworthy features is that it uses “cold” propellants. Compressed carbon dioxide to which acetone is added is pumped into a storage tank in the rocket at a pressure of 56.3 kilograms per square centimeter (800 pounds per square inch). Release of the pressurized mixture gives Cricket its thrust. Cricket is fired from its launcher by a separate charge of carbon dioxide in order to preserve the rocket’s fuel for flight. This rocket was developed by Texaco Experiment, Inc., for the U.S. Air Force’s Cambridge Research Laboratory. The Cricket is from Texaco, Inc.