ORIONPA-1

2010

PA-1 Trajectory Overview:

 Time Event

In Seconds

1 0.00 Abort Motor (AM) and

 Attitude Control Motor (ACM) Ignition

2 6.45 AM Burnout

3 10.05 ACM Begins Vehicle Reorientation

4 15.77 End Reorientation

5 21.03 Launch Abort System (LAS) Jettison

6 22.02 Forward Bay Cover Jettison

7 24.56 Drogue Parachutes Deploy 

8 30.56 Pilot Parachutes Deploy

9 49.32 LAS Touchdown

10 52.54 Reach 33 ft/sec 

www.nasa.gov 11 96.83 Crew Module Touchdown

Pad Abort-1 is a NASA 

flight test of a system that 

could be used to rescue a 

crew and its spacecraft in 

case of emergencies at 

the launch pad.

National Aeronautics and Space Administration 
NASA’s latest flight test, called Pad Abort 1 (PA-1), will be 

conducted at the Orion Abort Flight Test Launch Complex 32E at 

the U.S. Army’s White Sands Missile Range (WSMR) near Las 

Cruces, N.M. 

Although it is a component of the agency's Constellation program 

and Orion crew exploration vehicle, the future of which is currently 

under deliberation in the U.S. Congress, the test will be conducted 

as part of NASA's ongoing mission to develop safer space vehicles 

for all human spaceflight applications. Information gathered through 

PA-1 testing will be valuable in design and development of future 

systems built for use in providing emergency egress for space crews 

and vehicles. The launch abort system, or LAS, is designed to 

activate within milliseconds in the event of an emergency on the 

launch pad or during initial ascent. It consists of three motors: the 

abort motor that fires nearly 500,000 pounds of thrust to pull the 

crew module up and away from the launch vehicle; the attitude 

control motor that exerts up to 7,000 pounds of steering force to 

reorient the vehicle's position; and the jettison motor that separates 

the crew module from the launch abort system so that parachutes 

can be deployed for a safe landing. 

Testing the LAS performance and LAS to crew module interface are 

the principal objectives of PA-1. The integrated LAS system 

performance cannot be adequately tested except in abort flight test 

conditions such as PA-1. The information gathered from the test 

also will help reduce uncertainties in the models and analysis, 

thereby removing excess conservatism and improving safety.

Some of the primary objectives are to: 

• Demonstrate ground-initiated abort;

• Demonstrate the capability of the LAS to propel the module to 

 a safe distance from a launch vehicle during a pad abort;

• Demonstrate stability and control characteristics of a crew

 module in regards to the LAS;

• Obtain LAS/crew module interface structural loads and external 

 acoustics data;

• Determine the performance of the abort, jettison and attitude 

 control motors;

• Demonstrate abort event sequencing from abort initiation 

 through LAS jettison.

Secondary objectives of the test are to:

• Demonstrate parachute assembly system event 

 sequencing;

• Demonstrate the performance of the main parachute 

 system.

This data will have wide applicability to future launch vehicles and 

will also demonstrate the performance of three new types of motors 

and innovations in their design.

1. Attitude Control Motor

The LAS employs an attitude control motor that provides precision 

control of flight buy utilizing a variable high-thrust rocket technology 

that eliminates heavy ballast, aerodynamic canards and reliance on 

static aerodynamic stability without control that were used in Apollo 

designs. The technology heritage of the attitude control motor is 

related to missile steering systems, but has never been produced at 

this large scale (the attitude control motor is 32 inches in diameter). 

The ACM development employs advanced high-temperature, 

high-pressure and high-strength composite materials technologies 

that are adaptable to future space exploration applications.

2. Jettison Motor

The jettison motor has scarfed nozzles and is configured similarly to 

the Apollo jettison motor, although it is much bigger to 

accommodate the increased mass and performance of the Orion 

LAS. Because the jettison motor is used to jettison the LAS in both 

the nominal scenario and emergency abort situations, its function 

must be extremely reliable. 

3. Abort Motor

The abort motor has advanced the state of knowledge in rapid burn 

fuels, reverse flow solid rocket motor designs, composite casing, 

and direct strike lightning protection technologies adaptable to 

future exploration applications. It uses a high strength-weight 

graphite/epoxy composite motor case and igniter. Computational 

fluid dynamics were extensively used to design a novel 

electron-beam welded 4340 steel manifold and reverse flow nozzles. 

This geometry places the abort motor plume farther from the crew 

module, eliminating the need for a tower structure used in the Apollo 

configuration. These innovations minimize mass and maximize 

payload. 

National Aeronautics and Space Administration

Lyndon B. Johnson Space Center

Houston, Texas 77058

www.nasa.gov