Apollo 13 (AS-508): Houston, We Have A Problem. Essay, Research Paper

Apollo 13 (AS-508): Houston, we have a problem.

The Apollo 13 mission was launched at 2:13 p.m. EST, April 11, 1970 from

launch complex 39A at Kennedy Space Center. The space vehicle crew consisted of

James A. Lovell, Jr. commander, John L. Swigert, Jr., command module pilot and

Fred W. Haise, Jr. lunar module pilot.

The Apollo 13 Mission was planned as a lunar landing mission but was

aborted en route to the moon after about 56 hours of flight due to loss of

service module cryogenic oxygen and consequent loss of capability to generate

electrical power, to provide oxygen and to produce water.

Spacecraft systems performance was nominal until the fans in cryogenic

oxygen tank 2 were turned on at 55:53:18 ground elapsed time (GET). About 2

seconds after energizing the fan circuit, a short was indicated in the current

from fuel cell 3, which was supplying power to cryogenic oxygen tank 2 fans.

Within several additional seconds, two other shorted conditions occurred.

Electrical shorts in the fan circuit ignited the wire insulation, causing

temperature and pressure to increase within cryogenic oxygen tank 2. When

pressure reached the cryogenic oxygen tank 2 relief valve full-flow conditions

of 1008 psi, the pressure began decreasing for about 9 seconds, at which time

the relief valve probably reseated, causing the pressure to rise again

momentarily. About a quarter of a second later, a vibration disturbance was

noted on the command module accelerometers.

The next series of events occurred within a fraction of a second between

the accelerometer disturbances and the data loss. A tank line burst, because of

heat, in the vacuum jacket pressurizing the annulus and, in turn, causing the

blow-out plug on the vacuum jacket to rupture. Some mechanism in bay 4 combined

with the oxygen buildup in that bay to cause a rapid pressure rise which

resulted in separation of the outer panel. The panel struck one of the dishes of

the high-gain antenna. The panel separation shock closed the fuel cell 1 and 3

oxygen reactant shut-off valves and several propellant and helium isolation

valves in the reaction control system. Data were lost for about 1.8 seconds as

the high-gain antenna switched from narrow beam to wide beam, because of the

antenna being hit and damaged.

As a result of these occurrences, the CM was powered down and the LM was

configured to supply the necessary power and other consumables.

The CSM was powered down at approximately 58:40 GET. The surge tank and

repressurization package were isolated with approximately 860 psi residual

pressure (approx. 6.5 lbs of oxygen total). The primary water glycol system was

left with radiators bypassed.

All LM systems performed satisfactorily in providing the necessary power

and environmental control to the spacecraft. The requirement for lithium

hydroxide to remove carbon dioxide from the spacecraft atmosphere was met by a

combination of the CM and LM cartridges since the LM cartridges alone would not

satisfy the total requirement. The crew, with direction from Mission Control,

built an adapter for the CM cartridges to accept LM hoses.

The service module was jettisoned at approximately 138 hours GET, and

the crew observed and photographed the bay-4 area where the cryogenic tank

anomaly had occurred. At this time, the crew remarked that the outer skin

covering for bay-4 had been severely damaged, with a large portion missing.

The LM was jettisoned about 1 hour before entry, which was performed

nominally using primary guidance and navigation system.