A Successful Failure: The Flight of Apollo Little Joe II A-003

Probably the most dangerous part of a space mission is launch which is why almost all crewed spacecraft have had launch abort options to cover all phases of ascent. In order to support abort options on the pad through the earliest parts of the flight, many crewed spacecraft have included a launch escape system (LES) consisting of an independent propulsion package to pull the crew capsule off and away from a malfunctioning launch vehicle and to safety. In six decades of crewed spaceflight, an LES was used only once for the “Soyuz T-10A” pad abort in 1983 (see “Soyuz T-10A: The First Crewed On-Pad Abort”).

The American Apollo, like the earlier Mercury spacecraft, also employed a LES but, its design and operation had to be verified through a series of ground and uncrewed flight tests to ensure that it would work as intended (especially in the early days of the Space Age before the availability of sophisticated computer simulation software). But even these test flights could go awry providing an even more severe test of a LES than intended. Perhaps the most famous of such flights from the Apollo era involved a flight of the Apollo Little Joe II designated A-003.

Testing the Apollo LES

The Apollo Launch Escape System (LES) was built by the Lockheed Propulsion Company (whose corporate parent is now part of Lockheed Martin). It consisted of a rocket motor assembly attached to the top of the Apollo Command Module (CM) by means of a truss framework with a total height of 9.9 meters and a mass of 4,200 kilograms. The main propulsion system of the LES of consisted of a solid rocket motor fitted with four nozzles that produced a nominal thrust of 650 kilonewtons for four seconds to lift the CM and LES away from the launch vehicle in case of an abort situation on the pad or during the initial phases of ascent. It also included a deployable canard system and a pitch motor rated at 18 kilonewtons to help stabilize the CM/LES during an abort and steer it out of the path of the malfunctioning launch vehicle. A smaller solid rocket motor with a pair of nozzles producing about 140 kilonewtons of thrust was used to pull the LES off of the ascending Apollo spacecraft when it was no longer needed to support abort options about three minutes after launch.

Diagram illustrating the major components of the Apollo Launch Escape System (LES). Click on image to enlarge. (NASA)

In order to test Apollo hardware under the most stressing flight conditions that it would experience during an abort situation at high altitudes and velocities, NASA contracted the production of the Little Joe II rocket. The original Little Joe was developed to perform abort tests in support of the Mercury program starting in 1959 (see “Giving Mercury Its Wings: The First Test Flights of NASA’s Mercury Program“). The Little Joe was meant to be a simple, adaptable and inexpensive launch vehicle that would employ various combinations of readily available solid rocket motors firing together or in a preplanned sequence to lift test hardware to a desired speed and altitude to exercise the LES under a range of stressing abort situations. On May 11, 1962, the Convair Division of General Dynamics got the contract to develop and build the larger Little Joe II to support the Apollo program.

Diagram showing the typical configuration of the Apollo-Little Joe II. Click on image to enlarge. (NASA)

The Little Joe II was a fin-stabilized rocket with the same 3.96-meter diameter as the Apollo CM it was to lift. With the Apollo CM, a dummy service module (SM) and flightworthy LES in place, the Apollo-Little Joe II had a total height of 26.2 meters. The internal configuration of the Little Joe II allowed up to seven Aerojet General Algol 1D solid rocket motors to be carried with each producing 465 kilonewtons of thrust for 40 seconds. Similar Algol motors were used as the first stage in NASA’s Scout all-solid launch vehicle. Up to six smaller Recruit solid motors could also be carried to provide a 1.5 second kick to aid in liftoff. By varying the number and firing sequence of all these motors, a large range of abort situations could be simulated to altitudes as great as 60.9 kilometers (although none of the Apollo abort tests would actually fly that high).

An exploded view of the Little Joe II and its major components. Click on image to enlarge. (NASA)

A typical test would have the Little Joe II lift the CM/LES combination to a desired altitude and velocity at which point the LES would pull the CM away from the rocket to perform the abort test and subsequent recovery sequence. The White Sands Missile Range (WSMR) in New Mexico was chosen as the launch site for the abort tests because of the increasingly busy schedule at Cape Kennedy hampered abort test scheduling. In addition, land recoveries were easier to perform and less expensive than water recoveries.

Diagram showing the events of a typical Apollo-Little Joe II abort test flight. Click on image to enlarge. (NASA)

Like other early test flights of the Apollo, the first abort flights with the Little Joe II did not use actual Apollo flight hardware. Instead engineers employed boilerplate models which mimic the mass, shape and dynamic properties of actual flight hardware but otherwise only carried systems and instruments needed for the tests being conducted. Their low cost and adaptability made boilerplate models ideal for the first Apollo engineering test flights.

The Apollo A-003 Flight

By early 1965, NASA had already successfully flown a pair of CM boilerplates for the first Apollo Little Joe II flights (see “The First Apollo Little Joe II Launch”) as well as three boilerplate spacecraft on orbital flights with the Saturn I which tested LES separation, among other engineering tasks (see “The First Apollo Orbital Test Flight”, “The Second Apollo Orbital Test Flight” and “The Mission of Apollo A-103/Pegasus 1”). The objectives of the third Apollo Little Joe II flight, designated A-003, was to demonstrate the LES performance at an altitude approximating the upper limit for the system’s canard subsystem used to stabilize the LES and CM after an abort.

Diagram showing the configuration of Little Joe II vehicle number 12-51-2 for the Apollo A-003 abort test. Click on image to enlarge. (General Dynamics)

In order to meet the objectives for this flight, Little Joe II vehicle number 12-51-2 was fitted with six Algol motors making it the most powerful configuration of this rocket to fly. With three of these motors ignited at launch from WSMR Launch Complex 36, this Little Joe II generated 1,395 kilonewtons of thrust at lift off. Forty seconds after launch, the remaining three Algol motors would ignite followed by the activation of the LES 89.0 seconds after launch at an altitude of 2.8 kilometers above sea level some 2.5 kilometers downrange. At this point, the craft would be travelling at Mach 3.71. The CM would reach a peak altitude of 36.6 kilometers before executing procedures for a parachute landing in the desert. With a launch mass of 67,746 kilograms, including 2,288 kilograms of ballast, 12-51-2 would be the heaviest Little Joe II launched.

BP-22 being raised into position atop of the Little Joe II on April 15, 1965. (NASA)

The payload for this mission consisted of BP-22 and its LES which had a combined mass of 12,626 kilograms. In addition to carrying the flight systems needed to support the mission, BP-22 carried a radar beacon, instrumentation to make 58 measurements and a telemetry transmitter to return the data live during the flight. Mounted atop Little Joe II 12-51-2, the total launch mass of the stack was 80,372 kilograms – the heaviest of the series. The components for this mission started arriving at WSMR in February 1965 with BP-22 added to the stack at LC-36 on April 15.

Apollo Little Joe II A-003 on its pad at LC-36 in the White Sand Missile Range before its launch on May 19, 1965 . (NASA)

After an 8¼-hour countdown with no major problems encountered, the A-003 mission was launched at an azimuth of 356° and an elevation angle of 84° at 6:01:04 MST on May 19, 1965. Although ignition of the three Algol motors and physical pull out of the umbilical once the rocket rose 10 centimeters off the pad occurred as expected, the elevon on Fin 4 of the Little Joe II rocket malfunctioned 2.5 seconds after liftoff causing the ascending craft to start an unintentional spin. As the spin rate began to increase uncontrollably, the Little Joe II started disintegrating under the increasing loads about 24.4 seconds after launch. The LES was activated automatically only 26.3 seconds after launch with the roll rate reaching a maximum 335° per second.

A montage of images showing the breakup and subsequent abort of the Apollo A-003 flight. Click on image to enlarge. (NASA)

After being successfully pulled away from its launch vehicle, the LES canard was deployed 37.3 seconds after launch stabilizing the CM before LES jettison at 40.4 seconds. The CM’s drogue chute was deployed 42.4 seconds followed by the pilot chute and full inflation of the three main parachutes at 106 seconds. After reaching a peak altitude of only 6.04 kilometers, BP-22 came down 5.55 kilometers downrange after a flight lasting only 5 minutes and 3 seconds. Despite the unplanned low altitude abort and the high roll rate that affected the performance of the LES canards (which can only operate effectively with roll rates less than 20° per second), the test flight managed to meet all of its objectives with the dynamic pressure peaking at 3.5 times greater than planned. The way was now clear for the final abort test using an actual flight worthy CM instead of a boilerplate (see “The First Launch of Apollo Flight Hardware”).

BP-22 shown after it successfully landed in the desert following the unplanned abort of A-003. (NASA)

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General References

David Baker, The Rocket: The History and Development of Rocket & Missile Technology, Crown, 1978

Neil A. Townsend, “Apollo Experience Report – Launch Escape Propulsion Subsystem”, NASA Technical Note D-7083, March 1973

“Little Joe II Test Launch Vehicle, NASA Project Apollo – Final Report Volume II Technical Summary”, General Dynamics Convair Division GDC-66-042, May 1966