Centaur AC-8 Press Kit

8/8/2019 Centaur AC-8 Press Kit

1/19

t '-

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WE) 2-41 5UW WASHINGTON, D C. 20546 WO "1-69?7SFOR RELEASEt THURSDAY P.M.MARCH 24, 1966

RELEASE NO: 66-58

PROJECT: CENTAUR (AC-8)(To be launched no earlierE than March 29, 1966)


2/19

! r

SNATIONAL AERONAUTICS AND SPACE ADMINISTRATION TE WO 2-4155E WSASA WASHINGTON, D.C. 20546 TELS. WO 3-6925FOR RELEASE: THURSDAY P.M.MARCH 24, 1966

RELEASE NO: 66-58CENTAUR DEVELOPMENT

FLIGHT SCHEDULED FORLAUNCH MARCH 29

The seventh Atlas-Centaur launch vehicle is scheduled fora development flight from Cape Kennedy no earlier that March 29.


3/19

-2-

Atlas-Centaur vehicles also have been selected to launchMariner spacecraft on Mars flybys during the 1969 launchopportunity.

The AC-8 vehicle will carry a mass model of the Surveyorspacecraft which will be injected on a simulated lunar transfertrajectory toward an "imaginary Moon" following a 25-minutecoast period in Earth orbit. The mass model will not impactthe Moon but will be placed in a highly elliptical Earth orbit,


4/19

k --

-3-MISSION DESCRIPTION

Test Objectives

The prime purpose of the AC-8 mission is to demonstratethe capability of the Centaur vehicle to place a spacecraft ina parking orbit, i.e.: restart.Centaur's hydrogen-fueled enginesfollowing a coast phase in Earth orbit and place the spacecrafton a lunar trajectory.


5/19

-4-

The liquid hydrogen must be "bottomed" in the Centaur soit is in the right position to assure that boil-off vapor(hydrogen gas) is vented rather than liquid hydrogen. Smallullage rockets exert enough thrust to maintain propellants inthe proper location.

The restart capability provides greater flexibility invehicle launch operations. Launch windows, which are limited


6/19

-5-

-- The use of high-energy propulsion systems. (The AC-2flight in 1963 was the first known successful flightusing hydrogen-oxygen propellants.)

-- Centaur's capability to place a lunar spacecraft on adirect-ascent trajectory to the Moon, well within aspacecraft's midcourse maneuver capability toinsure an accurate landing.

-- Centaur's launch-on-time capability to meet narrow lunarand planetary launch windows.


7/19

-6-Flight Plan

After liftoff, AC-8 will rise vertically for the first 15seconds, then roll from a launcher heading of 115 degrees to aflight plane azimuth of 103 degrees. During boos er engineflight, the vehicle is steered by the Atlas autopilot.

After about 140 seconds of booster flight, the boosterengines are shutdown (BECO) and jettisoned. The


8/19

vehicle is in a weightless condition.

Tw o hydrogen-peroxide ullage rockets, each with three poundsthrust, are then fired to retain the propellants in the lower

-7-As Centaur's engines are shut down and the coast phase

ofbegins, two 50pound thrusthydrogen-peroxide rockets are fired

vehicle is in a weightless condition.Two hydrogen-peroxide ullage rockets, each with three pounds


9/19

-8-The Surveyor mass model is separated from Centaur and

injected toward its target in space -- a hypothetical Moonabout 236,000 statute miles from Earth.

Following spacecraft separation, the Centaur vehicle willperform a 180-degree reorientation maneuver, using its attitudecontrol system and two 50 pound thrusters. This alters Centaur's

to perform a retromaneuver.


10/19

. 6

-9-SLAUNCH VEHICLE

(All figures approximate)

Liftoff weight: 300,000 lbs.Liftoff height: 113 feetLaunch Complex: 36-BLaunch time: daylight hours (9 a.m. - 4 p.m., EST)

Centaur Stage


11/19

-10-

The Atlas first stage is 75 feet high, including theinterstage adapter, and uses a standard MA-5 propulsion system.It consists of two booster engines and a sustainer engine,developing 387,000 pounds of thrust. Two vernier engines of1,000 pounds thrust each provide roll directional control.

The Centaur second stage including the nose fairing, is 48feet long. It is powered by two improved RL-10 hydrogen-oxygen


12/19

-11-

air friction from causing excessive boil-off of liquid hydrogenduring flight through the atmosphere. The nose fairing protectsthe payload from this same heat environment.

Several modifications have been made to the Atlas-Centaurvehicle for the AC-8 flight. All pertain to problems associatedwith two-burn missions. Major changes are:

-- Redesign of the hydrogen venting system. Since venting


13/19

-12-recirculation line is designed to avoid a similar conditionin the engines by prechilling the propellant feed lines.

-- Addition of a hydrogen tank slosh baffle assembly. Thissystem, together with the 50-pound thrusters and system mod-ifications mentioned earlier, is designed to minimize dis-turbances in the LH2 tank during weightlessness so thepropellants will be in proper location at the pump inlet fo rengine restart.


14/19

--

[,-

,;I ' '

^ -13-

. . Mass.Model ,

The 1,700-pound mass model which;AC-8 will carry aoes notresemble a Surveyor spacecraft in appearance but is ballastedto simulate Surveyor's retrorocket and solar panel/planar arrayantenna assemblies. The model also will be equipped with anS-band transponder to permit post-separation tracking.

The model is made for in-flight separation using an


15/19

-14-

Booster stage data will relate primarily to engine functionsand flight control systems, plus standard vibration, structuralbending and temperature information.

The Surveyor mass model will be instrumented to measuretemperatures around the spacecraft adapter and pressure andvibration levels at the top of the antenna assembly.

flight and portions of


16/19

-''

-15-

Additionalprecision tracking: data on Centaur andi themodel, will be- supplied by thei Smithsonian Astrophysical Obser-vatory'st worldwide- network of Baker-Nunn cameras.

CENTAURJ PROJECT. TEAM.

The; Centaur program! is under the- .overall direction" of NASA-'s


17/19

AI

Convafr Division of General Dynamics Corp., San Diego,is primie contractor for the Canttaur vehicle, including-theAtlas booster. Grant L. Hansen, vice,president, launch vehicleprograms, is responsible for the Atlas-Centaur program.(Convair also designed and built the AC-8. mass model.)

Pratt and.Whitney Aircraft Div. of United Aircraft Corp.,


18/19

a&Sco"

c

4

U5

I


19/19

9

-1213

5 AC-8 TRAJECTORYS(All figures approximate)

NOMNAL ALMUDE SURFACE RANGE, V- MMSEVENT ',____ SKE STAITUE MI STAWtE M___

Si 1 LIFTOFF. 0 0 0 02 BOOSTER oUTOFF3 AND BOOS~Rlt JETTISON 142 36 50 5600

-p

3 JETTISON INSULATION PANELS 176 57 100 62004 j IETTISON NOSE FAIRING 204 72 147 6850

s I5 SUSTAINER ENGINE CUTOFF 240 8 216 7900 fAND ATLAS SEPARATION 6 76 CENTAUR ENGINE START 248 92 237 7900

2 7 CENTAUR ENGINE CUTOFF 573 105 1240 16,5508 COAST IN EARTH ORBIT --9 CENTAUR SECOND BURN 2074 112 7960 16,55010 CENTAUR ENGINE CUTOFF 2181 121 8500 23,60011 SPACECRAFT SEPARATION 2250 137 8760 23,60012 START REORIENTATION 2255 139 8800 23,60013 START RETROTHRUST 2490 405 10,200 22,800

ORBITAL ELEMENTS: Apogee PerigeeMASS MODEL: 575,000 miles 100 miles

CENTAUR: 385,000 miles 100 miles

7. - /---------- -- - --* -- _----

Documents

Centaur AC-8 Press Kit