Unnamed Small Rocket Engines

*The information presented in this article is **true for my alternate history**, but either completely false, or only partly true for real life.*

This page lists a number of small unnamed rocket engines and their parameters.

### **S-IVB ullage motors (2 or 3 used):**

* Burn Time: 3.8 s
* Thrust: 15 kN

Each Thiokol Huntsville TX-280-10 ullage motor was 36.3" long, 8.3" in diameter and weighed 88.4 lb, 58.7 of which was a case-bonded solid propellant with a 5-point star grain. It produced 3,420 lbT for 3,81 seconds. The motor cases were from 4135 steel and a steel nozzle was also provided.

### **S-II ullage (4 used):**

* Burn Time: 3.7 s
* Thrust: 100 kN

The nozzles were just above the S-IC/S-II first separation plane and were canted outward 10° to reduce the moment that would result from one or more motors malfunctioning and to reduce exhaust plume impingement. With any one ullage motor inoperative, the remaining ones were capable of maintaining a minimum vehicle acceleration necessary for proper S-II engine ignition.

The RS-U-601 ullage motors were originally built by Rocketdyne in MacGregor, Texas, later by Hercules, Inc. in Wilmington, Delaware . Each 488 lb ullage motor had a 4130 steel case, phenolic exit cone with metal shell, and 337 lb of case-bonded propellant that was 82% ammonium perclorate and 18% carboxy terminated polybutadiene (CTPB) binder cast in a four-point-star grain configuration. The motor was 89" long, 12.5" in diameter, and developed 22,700 lbT for 3.7 seconds.

### **S-II retrorockets (4 used):**

* Burn Time: 1.4 s
* Thrust: 155 kN

A **retrorocket system** retarded the S-II stage affecting separation from the S-IVB stage. Two EBW firing units, two EBW detonators, two CDF manifolds, nine CDF assemblies, eight pyrogen initiators, and four Thiokol Elkton TE-M-29-4 retrorockets comprised the system. The components were connected to each other in a manner similar to that of the ullage rocket system. The retrorockets were mounted 90° apart in the aft end of S-II/S-IVB interstage between stations 2519 and 2633. The retrorockets were canted out from the vehicle centerline approximately 3° with the nozzles canted out 9.2° from the centerline.

Each retrorocket had a 380 lb gross weight and consisted of a 4130 steel case that was 9" in diameter and 90.68" long containing 268.2 lb of case-bonded, single-grain solid propellant with a tapered, five-point star configuration produceing 34,800 lbT during its 1.52 sec burn time. A steel nozzle raised the retrorocket's total length to 107"/

### **S-IC retrorockets (8 used):**

* Burn Time: 0.5 s
* Thrust: 337 kN

The forward-facing retro rocket motors were housed in the outboard F-1 aerodynamic fairings and fired through the aluminum fairing tops. The Thiokol TE-M-424-6 solid-propellant retro rocket motors each produced about 88,600 lbT for 0.667 sec and were fired just after staging in order to affect Stage 1 and Stage 2 separation before Stage 2 ignition. The retros had a diameter of 15.2", were 84.3" long and weighed 506 lb, which included a 208 lb propellant load consisting of 78% solids and 2% aluminum with the remaining 20% being a polysulfide binder. The propellant was cast with a 12-point star grain. While there were provisions for eight retro rockets, some flights omitted retro motors as a weight-saving measure.

### **NOM-MS ullage (launch) (8 used):**

* Burn Time: 3.7 s
* Thrust: 100 kN

### **MS-IC-2-NOM-MS additional retrorockets (4 used):**

* Burn Time: 1.2 s
* Thrust: 200 kN

### **NOM-MS retrorockets (Neptune) (6 used):**

* Burn Time: 1.2 s
* Thrust: 200 kN