Appendix 8
Block II vs. Block I Apollo Spacecraft;
Hardware, Changes, Tests
[From "Manned Space Flight Report: Block II Spacecraft" in House Committee on Science and Astronautics, Subcommittee on NASA Oversight, Investigation into Apollo 204 Accident: Hearings, 90th Cong., 1st sess, 3, no. 4, May 10, 1967, 223-35.]
Subsystems and Units Unchanged for Block II CSM
- Launch escape system
- Command module reaction control system
- Service module reaction control system engine cluster
- Fuel cell power plants and entry batteries
- Cryogenic oxygen and hydrogen storage system
- Sequential events control system
- Emergency detection system
- Spacecraft LM adapter
- Atmosphere supply system
- Primary equipment cooling loop
- Waste management system
- Crew couches
- C-band radar transponder
- Ordnance devices
- Parachutes and recovery aids
New Subsystems and Units in Block II CSM
- Docking system
- Docking tunnel and probe
Umbilical and pressurization
Rendezvous radar transponder
- Sequence controllers
- LM docking and separation events
- S-band antennas
- Flush omnidirectional
High gain
Subsystems and Units Changed in Block II CSM
Structure:
- Command module
- Docking provisions, mechanism, and hatch
Extravehicular capability
CM/SM mechanical connection
Scientific airlock available
- Service module
- Propellant tanks
Empty bay
Internal rearrangement
Structural redesign
Radiator areas
RCS mounting panels
Propulsion:
- Service module propulsion system
- Mixture ratio
Thrust chamber
Gimbal actuator
- Service module reaction control
- Propellant capacity
Monomethylhydrazine fuel
Crew support:
- Environmental control system
- Redundant cooling loop
Radiator design and area
- Spacesuit
- Apollo suit
Extravehicular capability
- Displays and controls
- Panel structure
Electroluminescent lighting
Entry monitor system
Power and communication:
- Electrical power system
- Radiator area
Distribution bus added
Cable harnessing
Pyrotechnic initiator
Wire deadfacing at separation
- Unified S-band
- Primary mode for all communications
Repackaged
Simultaneous data and tape dump or TV
Electrical redundancy
- Voice VHF
- Redundant and duplex
Guidance and control:
- Guidance and navigation
- Digital autopilot
Computer repackaged
Electronics repackaged
Navigation base support
- Stabilization and control system
- Revised interface
Electronics repackaged
Redundant attitude display
Atmospheric entry and touchdown:
- Heatshield
- Redistributed ablative thickness
Truncated apex
Umbilical location
Flush antennas
- Earth-landing system
- Steel parachute risers
Parachute attach points
Repackaged
Crew Safety Systems
- Launch escape system
- Emergency detection system
- Sequential events control system
- Earth-landing system
- Environmental control system
- Reaction control system
- Electrical power system
- Command module heatshield
- Structure system
Mission Success Systems
- Spacecraft adapter
- Waste management system
- Guidance and control system
- Stabilization and control system
- Communications system
- Displays and controls
- Service propulsion system
Subsystems with Internal Redundancy
| (Subsystem) | (Major function) |
|---|---|
| CM reaction control system | Attitude control Lift vector control |
| SM reaction control | Attitude control S-IVB/CSM separation CM/SM separation |
| Communications system | Navigation data Voice, telemetry, and tracking Recovery |
| Electrical power system | Electrical power |
| Environmental control system | Equipment cooling Cabin environmental control |
| Sequential events control system | Separation signals Earth-landing functions |
| Emergency detection system | Launch vehicle malfunction |
| Earth-landing system | Atmospheric descent Uprighting at impact |
Backup System Capabilities for Earth-Orbital Flight
| Subsystem | Major Function | Backup |
|---|---|---|
| Service propulsion system | Deorbit | SM-RCS; CM-RCS |
| Command module reaction control system | Attitude control | SM-RCS spinup before separation for ballistic reentry |
| Guidance and control system | Attitude, translation, and lift vector control Control of SPS burns | Stabilization and control system |
| Stabilization and control system | Backup attitude, translation, and SPS control | Manual |
Flight Safety Systems Changed in Block II
- Earth-landing system
- Service module reaction control system
- Electrical power system
- Environmental control system
- Command module heatshield
- Structural system
- Service propulsion system
Environmental Control System Changes for Block II before AS-204 Accident
- New radiator design:
- Increased size.
- Selective stagnation control.
- Secondary loop tubes.
- Secondary coolant loop:
- Additional pump.
- Redundant cold plate passages.
- Repackage environmental control unit (ECU):
- Coolant pumps relocated external to ECU, repackaged, and capacity increased.
- Coolant reservoir located external to ECU.
- Redesigned suit heat exchanger.
- LM pressurization capability.
- Relocate postlanding ventilation valves.
- Redesign steam duct.
- Add rendezvous radar cold plates in SM.
Proposed ECS Changes for Block II after AS-204 Accident
- Add armor plating to exposed solder joints.
- Change soldered-aluminum oxygen lines to stainless steel.
- Rapid cabin repressurization.
- Improve accessibility of selected ECS controls.
- Shields for plumbing lines.
- Optional use of air in cabin during launch.
- Emergency breathing masks.
- Add quick disconnects to environmental control unit.
- Replace selected materials.
Block I - Major Ground Test Programs
| Test Article | Test | Purpose |
|---|---|---|
| CM BP-6A | Parachute drop-testing of boilerplate CM | Flight-qualify earth recovery system by series of aircraft drop tests |
| SM-001 | SPS propulsion ground test | Demonstrate SPS performance (oxidizer-to-fuel ratio = 2), 2nd SPS-structure compatibility |
| SLA | Static structural test of spacecraft-LM adapter | Test SLA static structural load capability (ultimate) |
| CSM 004 | Static and thermal structural ground test | CM static structural load test (ultimate) CSM static structural load test (ultimate) CM thermal structural load test (reentry design) |
| CSM 007 | Varied spacecraft testing | CM and SM acoustic vibration environment test CM water-landing impact drop test Postlanding systems operational/crew compatibility tests (uprighting, postlanding ECS, postlanding communications) |
| CSM 008 | Thermal vacuum test of complete systems spacecraft | Demonstration of structural, integrated subsystems and crew compatibility under thermal vacuum environment |
White Sands Missile Range Flight Tests
| Test Article | Test | Purpose |
|---|---|---|
| BP-6 | Boilerplate - LES pad abort flight test | Demonstrate launch escape system's pad abort performance |
| BP-12 | Boilerplate - LES transonic abort flight test | Demonstrate launch escape system's transonic abort performance |
| BP-23 | Boilerplate - LES high-dynamic-pressure abort flight test | Demonstrate launch escape system's maximum-dynamic-pressure-region abort performance |
| BP-23A | Boilerplate - LES pad abort flight test | Demonstrate launch escape system's pad abort performance with Canard, BPC, and major sequencing changes |
| CSM 002 | Spacecraft structure - SM boost environment and LES tumbling abort flight | Determine actual spacecraft SM's dynamic structural response to boost dynamic loads Demonstrate launch escape system's tumbling abort performance and plume-impingement-load capability of CSM |
Block II - Major Ground-Test Programs
| Test Article | Test | Purpose |
|---|---|---|
| BP-6B | Parachute drop-testing of boilerplate CM | Flight-qualify earth recovery system by series of aircraft drop tests |
| F-2A | Fixture for SPS testing | Evaluate performance effects on SPS engine of fuel and oxidizer mixture's ratio change from 2.0 to 1.6 |
| 180 degree SM segment | Acoustic test article (SM) testing | Quality SM structure and systems to launch and boost vibration environment |
| CM 28-1 | Static and dynamic structural testing | Evaluate water impact on CM structure Docket CM/LM interface static structural tests |
| CMS 2S-2 | Static structural testing | Static-test CM and SM structures (ultimate) |
| CMS 2TV-1 | Complete systems spacecraft thermal vacuum testing | Demonstrate structural, integrated subsystems, crew compatibility, and life support in thermal vacuum environment |
Block II - Revisions of and Additions to Major Ground-Test Programs
| Test Article | Test | Purpose |
|---|---|---|
| 2TV-1 | Complete spacecraft thermal vacuum | Qualify fire related changes |
| 004A, 007A | Unified hatch qualification | Functionally qualify acoustic testing, postlanding testing |
| CSM | Acoustic vibration | Demonstrate functional and structural integrity of stacked CSM-SLA |
| Material | Materials evaluation | Continue evaluation of non- or low-flammable material |
| Boilerplate | Command module fire test | Evaluate fire propagation in flight-configuration CM interior |
| EMU articles | Extravehicular mobility unit qualification | Qualify Block II unit with materials change |
| ECU articles | Environmental control unit qualification | Qualify Block II unit with all required modifications |
| Next |