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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