D.3 Delta Launch and Performance History
The Delta launch-vehicle family originated in 1959 with a NASA contract to Douglas
Aircraft Company, now McDonnell Douglas Corporation.               The Delta, using
components form USAF's Thor IRBM program and USN's Vanguard launch-vehicle
program, was operational 18 months later. On May 13, 1960, the first Delta was
launched from Cape Canaveral with a 179-pound Echo-I passive communications
satellite. In the intervening years, the Delta has evolved to meet the ever-increasing
demands of its payloads - including weather, scientific, and communications satellites.
Each Delta modification corresponded to an increase in payload capacity. Table 42
shows a summary of Delta configurations since the beginning of the program. 1101

The Delta 7925, the latest vehicle in the series, is a three-stage liquid-propellant vehicle
with nine solid-propellant strap-on booster motors. For propellants, the Delta uses RP-
1 and liquid oxygen in Stage 1, and nitrogen tetroxide and aerozine 50 in Stage 2.
Stage 3 consists of a Payload Assist Module (PAM) with a solid-propellant motor. The
strap-on boosters are Hercules graphite epoxy motors (GEMs) using HTPB-type solid
propellant. At liftoff, the liquid-propellant Stage-1 engine and six of the nine GEMs are
ignited. The remaining three GEMs are ignited some 65 seconds later.
               Table 42. Summary of Delta Vehicle Configurations
 Configuration Description
 Delta          Stg. 1: Modified Thor. MB-3 Blk I engine
                Stg. 2: Vanguard AJl0-118 propulsion system
                Stg. 3: Vanguard X-248 motor
 A              Stg. 1: Erurine replaced with MB-3 Blk II
 B              Stg. 2: Tanks lengthened; higher energy oxidizer used
 C              Stg. 3: Replaced with Scout X-258 motor
                PLF: Bulbous replaced low drag
 D              Stg. 0: Added 3 Thor-developed SRMs (Castor I)
 E              Stg. 0: Castor II replaced Castor I
                Stg. 1: MB-3 Blk III replaced Blk II
                Stg. 2: Propellant tank diameters increased
                Stg. 3: Replaced with USAF-developed FW-4 motor
                PLF: Fairing enlarged to 65-inch diameter
 J              Stg. 3: TE-364-3 used
 L,M,N          Stg. 1: Tanks lengthened, RP-1 tank diameter increased
                Stg. 3: Varied: FW-4 (L), TE-364-3 (M), none (N)
 M-6, N-6       Stg. 0: Six Castor IIs employed
 900            Stg. 0: No Castor Ils employed
                Stg. 2: Replaced with Transtage AJ10-118F engine
 1604           Stg. 0: Six Castor IIs employed
                Stg. 3: Replaced with TE-364-4


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