Mercury - Background
Project Mercury, born from America's first blueprints to put human crews in space, was also the genesis for some of the space hardware that would fly astronauts to the Moon
Mercury's 25 flights (6 manned) had just begun when the ambitious Apollo program was taking shape
President John Kennedy's pronouncement of the Apollo lunar program goals reflected NASA's earlier commitment to human exploration of space, and increased the importance of the hardware that was designed and flown under the Project Mercury
Mercury - Background
Project Mercury began as an advanced manned space flight program shared by the Department of Defense and the National Advisory Committee on Aeronautics (NACA)
Manned surveillance satellites were a tactical response to the threats of the Cold War with the Soviets and accelerated by the Space Race
Man-in-Space-Soonest was a USAF project that was converted into Project Mercury after the creation of NASA on October 1, 1958
The Space Task Group was empanelled soon after NASA was created to plan and develop America’s first manned space flight project - Mercury
Mercury - Background
The three Mercury program objectives that were adopted when the program was accepted were:
1. To place a manned spacecraft in orbital flight around the Earth
2. To investigate man's performance capabilities and his ability to function in the environment of space
3. To recover the man and the spacecraft safely
Mercury - Background
To help expedite the program and enhance the safety of the flight and operational crews, guidelines were detailed to attain the program objectives
1. Existing technology and off-the-shelf equipment should be used wherever practical
2. The simplest and most reliable approach to system design would be followed
3. An existing launch vehicle would be employed to place the spacecraft into orbit
4. A progressive and logical test program would be conducted
Mercury - Background
Cost was a concern throughout the life of the project which dictated that hardware already developed be used for the project whenever possible. To help reduce cost and accelerate the program development, the following program requirements were established:
1. The spacecraft must be fitted with a reliable launch-escape system to separate the spacecraft and its crew from the launch vehicle in case of impending failure
2. The pilot must be given the capability of manually controlling spacecraft attitude
3. The spacecraft must carry a retrorocket system capable of reliably providing the necessary impulse to bring the spacecraft out of orbit
4. A zero-lift body utilizing drag braking would be used for reentry
5. The spacecraft design must satisfy the requirements for a water landing
Mercury Capsule
Because of the extreme reentry heat, the Mercury capsule design would require effective heat rejection by reducing reentry energy through shock wave dispersion This solution was
provided by the broad, curved reentry shield
Both heat absorption and heat rejection methods were considered for heat shielding, although only the ablative heat rejection shield was implemented in the Mercury capsule
Mercury Capsule
Lower heating on suborbital trajectories allowed a simpler heat sink on the reentry shield of the capsule
A beryllium heat sink would absorb much of the energy of reentry, which would then release the heat quickly at splashdown This design was not used in
the program because of the uncertainties of the feat flow
The ablation heat shield would be more difficult to design, but would be chosen for the suborbital and orbital Mercury flights
Mercury Capsule
Mercury's structure was made up of three titanium sections in a semimonocoque design (the skin provides part of the structural strength)
The three sections made up the primary structural assembly as follows:
1. Afterbody - the small cylindrical top that housed the reentry parachutes and recovery components, and, for later vehicles, allowed the astronaut emergency egress
2. Midbody - the main conical structure consisted of a dual shell. The inner provided the primary structural strength, while the outer shell added to the structural integrity and thermal control with its beryllium and Rene (nickel alloy) thin shingles
3. Forebody - the reentry face that comprised three shells, the inner one a pressure bulkhead for the cabin, the second a heat shield support, and the outer the ablation shield composed of glass fiber and high temperature resin
Mercury Capsule
Mercury Capsule
Mercury Capsule
Mercury capsule specs
Construction Titanium shell with beryllium and nickel alloy outer
layers
Height 11.5 ft (28 feet including the launch escape system
tower)
Diameter 6.5 feet
Interior volume 60 ft3
Launch weight 4,300 lb (MA-6)
Orbit weight 3,000 lb (MA-6)
Mercury Capsule
Ensuring crew survival of a variety of expected launch accidents was looked at carefully, which led to the general conclusion that a launch abort system could offer a reliable method for crew escape and survival for most contingencies
From that assumption, the Mercury capsule escape system was created by one of America's premier but unheralded spacecraft engineers, Maxime Faget
His escape system proved to be simple, reliable, effective, and inexpensive; enough so that its basic design was used for the Apollo Command Module, and is being integrated into NASA's new Orion Crew Exploration Vehicle
Mercury Capsule + Escape Tower
Mercury Capsule
Electrical power
Electrical power for the Mercury capsule was supplied by primary and backup batteries since the missions were short duration. The battery-supplied main buses were maintained at 24 Vdc and divided into two main groups. Those were the high priority circuits for critical operations, and low priority circuits for normal operations.
Total primary and backup power was supplied by the following: Three main batteries 3,000 WHr (Watt-hours)
each Two standby/backup batteries3,000 WHr each One isolated battery 1,500 WHr
Mercury Capsule
Electrical power
Alternating current was supplied to the AC loads by inverters feeding off of the DC battery buses
AC was generated to isolate the DC buses from the noise of the capsule fan motors and to supply the AC avionics/electronics in the Automatic Stabilization and Control System (ASCS)
Mercury Capsule
Communications
Communications functions for the Mercury capsule included:
UHF and HF for capsule audio communications between astronauts and ground controllers
Biotelemetry and spacecraft telemetry to ground stations
Command signals from ground control
Recovery signals from the capsule
Radar tracking from ground and/or recovery vehicles
Mercury Capsule
STDN ground stations for the Mercury orbital flights included:
Cape Canaveral, Florida Grand Bahamas Grand Turk Bermuda Grand Canary Island Kano, Nigeria Zanzibar Muchea, Australia Woomera, Australia Canton Island Kauai Island, Hawaii Point Arguello, California Guumas, Mexico White Sands, New Mexico Corpus Christi, Texas Eglin, Florida
Mercury Capsule
Environmental Control System (ECS)
Many of the life support systems for the Mercury capsule were first-of-a-kind, although a number of components were derived from life support systems used in the hypersonic X-15 spacecraft
A duplicate life support system was designed for the Mercury capsule cabin and for the astronaut's space suit, with both offering low-pressure (5.5 psi) pure oxygen, carbon dioxide removal, and thermal control
The separate ECS components provided a redundant environment for up to two days in orbit in case of a suit failure or malfunction
Environmental Control System
Mercury Capsule
Guidance, navigation and control
Mercury's guidance, navigation and control system was also called the Stabilization Control System (SCS)
Automatic and manual components of the SCS operated outboard thrusters that were powered by hydrogen peroxide (H2O2) propellant
Thrust operation was commanded by ground control, or by an automated sequencing control from onboard computations, or by manual control inputs from the pilot-astronaut
Mercury Capsule
Capsule attitude control and navigation functions were used for all flight segments, from booster separation to reentry
The primary functional systems within the Stabilization Control System included the following:
Automatic Stabilization and Control System (ASCS) Manual Rate Stabilization and Control System
(RSCS) Reaction Control System (RCS)
Mercury Capsule
Posigrade booster
After launch, the Mercury capsule would separate from the booster and capsule adapter, and enter programmed orbit using a solid-propellant posigrade rocket
The posigrade unit consisted of three small rocket motors, although only one of the rockets was needed for separation Redundancy was also supplied in a dual-igniter
assembly in each of the three motors
Mercury Capsule
Retrograde booster
The Mercury capsule's retrograde booster was a deorbit rocket package used to slow the capsule enough for the perigee to dip far enough into the atmosphere for sufficient atmospheric drag to initiate reentry
Mercury's three retrograde rockets were housed in the same container that housed the three posigrade motors
The entire booster package was held down with three metal straps anchored to the capsule bottom with explosive bolts
The booster unit was released sixty seconds from the retrograde burn and ejected from the capsule by coil springs
Mercury Retrofire Package
Little Joe
The Little Joe program was developed to investigate the Mercury capsule flight dynamics and aerodynamic characteristics at high speeds and high altitudes, and to check the launch escape system, and the capsule parachute and drogue parachute operations
Because of the booster's low cost and its utility, Little Joe missions were extended for evaluation of the physiological effects of suborbital flight on primates
Little Joe
Little Joe specs
Thrust 1,044 kN (235,000 lb)
Length 15.2 m
Diameter 2.03 m
Weight 12,700 kg (28,000 lb)
Fuel Solid (5 motor cluster)
Burn time 37 s
Launches 8
Failures 2
Redstone
The origins of the Redstone missile began two years before "Operation Paperclip" in 1945/46 which collected the German scientists and engineers working on the V-2 missile program
Quickly and quietly the U.S. Army shipped the personnel, including Wernher von Braun and the V-2s and documentation to the U.S
Redstone Missile
Length 69' 4" Width 70" Weight, empty 16,510 lb Weight, loaded 61,345 lb Payload 6,300 lb Range 50-175 nm Altitude 34-57 nm Flight time 288-375 sec Engine Rocketdyne NAA 75-110 (S-3) Fuel & oxidizer Ethyl alcohol and liquid
oxygen (LOX) Engine thrust 78.000 lb Turbopump propellant Hydrogen peroxide Guidance Inertial Trajectory control Jet vanes and aerofin
vanes Velocity (Mach)
Cutoff 2.9-4.8 Reentry3.0-5.5 Impact 1.2-2.3
Redstone & Jupiter
Length Redstone 83' including
tower (6' structure extension) Jupiter 60'
Width Redstone 70" Jupiter 105"
Weight, loaded Redstone 66,000 lb Jupiter 108,800 lb
Range Redstone 175 nm Jupiter 1,500 nm
Altitude Redstone 57 nm Jupiter 356 nm
Redstone & Jupiter
Approximate burn time Redstone 370 sec Jupiter 390 sec
Total flight time Jupiter 1,017 sec
Engine Redstone NAA 75-110 Jupiter NAA 150-200 S-3D
Fuel & oxidizer Redstone Ethyl alcohol (and
later Hydyne) and LOX Jupiter Kerosene and LOX
Engine thrust Redstone 78,000-83,000 lb Jupiter 150,000 lb
Redstone & Jupiter C
Turbopump propellant Redstone Hydrogen
peroxide Jupiter Main engine propellants
Guidance Inertial
Trajectory control Redstone Jet vanes and aerofin
vanes Jupiter Hydraulic main engine
articulation
Reentry capsule Redstone Mercury Jupiter-C Ablation shield on
base of conical structure (used for both warhead tests and early primate flights (Able & Baker)
Redstone Engine
Redstone NAA 75-110 engine
Redstone Conversion
NASA requested eight Redstone missiles from the ABMA in preparation for alterations and improvements that would be needed to upgrade the Redstone to a man-rated launch vehicle
Major differences between the Redstone IRBM and the Mercury Redstone included systems simplification for increased reliability and decreased complexity
Other alterations included:
Structure - Lengthened 6' to provide an additional 20 seconds of thrust, total weight increased to 66,000 lb
Redstone Conversion
Engine - Increased thrust to 78,000 lb, and hydrogen peroxide turbopump improvements
Instrumentation - Control sensing unit added to provide error signals and malfunctions, telemetry added to provide readings on attitude, vibration, acceleration, temperatures, pressures, thrust level, etc.
Flight control - A simpler, more reliable unit was incorporated to increase stability and reduce drift
Abort - Instrumentation and control components added in order to identify problems in thrust levels, engine vibration, electrical failure, etc.
Atlas
Convair (Consolidated Vultee Aircraft Corporation) was contracted to design the MX-1593 version of the Air Force's earlier MX-774 missile concept
MX-774, also known as the RTV-A-2 was a supersonic ballistic missile project that was commissioned when the Army and Air Force were separated
In 1954, a contract was awarded Convair to develop, test and manufacture the Atlas missile for the Air Force
The Atlas project introduced unique new technologies, many used in later missile and launch vehicle design
Atlas
Atlas technology innovations
Light-weight structure that employed a thin-wall stainless steel monocoque tank and body structure which was kept rigid by the internal tank pressure
Gimbaled rocket engines for effective and efficient ascent guidance (originally patented by Robert Goddard)
Detachable payload/warhead section
Stage-and-a-half approach of jettisoning the booster engines during the ascent
Both booster engines and center/sustainer engine ignited at liftoff
Boosters jettisoned at engine cutoff
Onboard digital computer for advanced functional controls
Atlas
Atlas D specifications
Diameter: 10 ft 16 ft at base Length: 75 ft. 10 in (85 ft 6 in
for ICBM configuration) Weight: 260,000 lb maximum at
launch Engines:
2 Rocketdyne LR105-NA strap-on boosters @ 154,000 lb thrust
1 Rocketdyne LR89-NA-3 sustainer @ 57,000 lb thrust
2 small vernier rockets for attitude correction @ 1,000 lb thrust
Engine thrust at launch: 360,000 lb Propellants:
Fuel: RP-1 (kerosene) Oxidizer: LOX Consumption: ~1,500 lb/s
Missions
Missions - Unmanned
Little Joe
Mercury hardware test flights
Designation LJ-1 through LJ-5B
8 flights total, 2 failures
First launch - August 21, 1959
Last launch - April 28, 1961
Missions - Unmanned
Mercury-Redstone 1 (MR-1) Launched November 21, 1960 - Accidental abort
Mercury-Redstone 2 (MR-2) Launched January 31, 1961 was a successful qualification flight for the first manned Mercury-Redstone mission
Missions - Unmanned
Mercury-Atlas 3 (MA-3) Launched April 25, 1961 - Single orbit flight of capsule # 8 and the Atlas booster that was commanded to self-destruct 43 seconds into the flight because of guidance errors. The escape system did operate properly and the capsule was recovered, refurbished, and reused on the subsequent MA-4 test flight.
Mercury-Atlas 4 (MA-4) Launched September 13, 1961 – Reflight of failed MA-3
Mercury-Atlas 5 (MA-5) Launched November 29, 1961 - The three-orbit mission carried the chimpanzee Enos in the man-rating checkout for the first manned orbital mission, MA-6
Missions - Manned
Mercury-Redstone 3 - America's first astronaut in space was Alan Shepard
Launched May 5, 1961
Mercury capsule #10 named Freedom 7
Suborbital flightSuborbital flight
15 min 22 sec duration15 min 22 sec duration
Missions - Manned
Mercury-Redstone 4 - NASA's second and last suborbital manned mission
MR-4 flight launched on July 21, 1961 with Virgil (Gus) Grissom in Liberty Bell 7
Mission duration 15 min 37 sec
Missions - Manned
Mercury-Atlas 6 - America's first manned orbital flight with John Glenn at the controls
Launched February 20, 1962 on a 3 orbit mission
Flight duration 4 hr 55 min 23 sec
Used the larger Atlas booster since the velocity needed to reach orbit was 28,400 km/h (17,600 mi/h) and the Redstone could supply only 8,300 km/h (5,100 mi/h)
Missions - Manned
Mercury-Atlas 7 - America's second manned orbital mission, MA-7
Astronaut Scott Carpenter
Launched May 24, 1962, in the Aurora 7
Mission duration (3 orbits) 4 hr 56 min 5 sec
Missions - Manned
Mercury-Atlas 8 (MA-8) Mercury-Atlas 8 (MA-8) mission was designated mission was designated Sigma 7Sigma 7
Launched October 3, Launched October 3, 1962, with astronaut 1962, with astronaut Wally SchirraWally Schirra
Six-orbit engineering Six-orbit engineering test flighttest flight
Mission duration 9 hr 15 Mission duration 9 hr 15 min 13 secmin 13 sec
Missions - Manned
Mercury-Atlas 9 was NASA's final Mercury mission
MA-9 was launched May 15, 1963 with astronaut Gordon Cooper in the Faith 7 spacecraft
22 orbits with a flight duration of 1 day 10 hr 19 min 49 sec
Mercury Summary
Four years from concept to completion
25 flights 6 manned
2 suborbital 4 orbital
20 Mercury capsules constructed
Cost: estimated at $1.6 billion in 2010 dollars
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