Apollo 13 {Command and Service Module (CSM)}
Description
Apollo 13 was intended to be the third mission to carry humans to the
surface of the Moon, but an explosion of one of the oxygen tanks and
resulting damage to other systems resulted in the mission being aborted
before the planned lunar landing could take place. The crew, commander
James A. Lovell, Jr., command module pilot John L. Swigert, Jr., and
lunar module pilot Fred W. Haise Jr., were returned safely to Earth on
17 April 1970.
Mission Profile
Apollo 13 was launched on Saturn V SA-508 on 11 April 1970 at
19:13:00 UT (02:13:00 p.m. EST) from pad 39A at Kennedy Space Center.
During second stage boost the center engine of the S-II stage cut off
132 seconds early, causing the remaining four engines to burn 34 seconds
longer than normal. The velocity after S-II burn was still lower than
planned by 68 m/sec, so the S-IVB orbital insertion burn at 19:25:40 was
9 seconds longer than planned. Translunar injection took place at
21:54:47 UT, CSM/S-IVB separation at 22:19:39 UT, and CSM-LM docking at
22:32:09 UT. The S-IVB auxilliary propulsive system burned at 01:13 UT
on 12 April for 217 seconds to put the S-IVB into a lunar impact
trajectory. (It impacted the lunar surface on 14 April at 01:09:41.0 at
2.75 S, 27.86 W with a velocity of 2.58 km/s at a 76 degrees angle from
horizontal.) A 3.4 second mid-course correction was made at 01:27 UT on
13 April.
A television broadcast was made from Apollo 13 from 02:24 UT to 02:59
UT on 14 April and a few minutes later, at 03:06:18 UT Jack Swigert
turned the fans on to stir oxygen tanks 1 and 2 in the service module.
The Accident Review Board concluded that wires which had been damaged
during pre-flight testing in oxygen tank no. 2 shorted and the teflon
insulation caught fire. The fire spread within the tank, raising the
pressure until at 3:07:53 UT on 14 April (10:07:53 EST 13 April;
55:54:53 mission elapsed time) oxygen tank no. 2 exploded, damaging
oxygen tank no. 1 and the interior of the service module and blowing off
the bay no. 4 cover. With the oxygen stores depleted, the command module
was unusable, the mission had to be aborted, and the crew transferred to
the lunar module and powered down the command module.
At 08:43 UT a mid-course maneuver (11.6 m/s delta V) was performed
using the lunar module descent propulsion system (LMDPS) to place the
spacecraft on a free-return trajectory which would take it around the
Moon and return to Earth, targeted at the Indian Ocean at 03:13 UT 18
April. After rounding the Moon another LMDPS burn at 02:40:39 UT 15
April for 263.4 seconds produced a differential velocity of 262 m/s and
shortened the estimated return time to 18:06 UT 17 April with splashdown
in the mid-Pacific. To conserve power and other consumables the lunar
module was powered down except for environmental control,
communications, and telemetry, and passive thermal control was
established. At 04:32 UT on 16 April a 15 second LMDPS burn at 10%
throttle produced a 2.3 m/s velocity decrease and raised the entry
flight path angle to -6.52 degrees. Following this the crew partially
powered up the CSM. On 17 April at 12:53 UT a 22.4 second LMDPS burn put
the flight path entry angle at -6.49 degrees.
The service module, which had been kept attached to the command
module to protect the heat shield, was jettisoned on 17 April at
13:15:06 UT and the crew took photographs of the damage. The command
module was powered up and lunar module was jettisoned at 16:43:02 UT.
Any parts of the lunar module which survived atmospheric re-entry,
including the SNAP-27 generator, planned to power the ALSEP apparatus on
the lunar surface and containing 3.9 kg of plutonium, fell into the
Pacific Ocean northeast of New Zealand. Apollo 13 splashed down in the
Pacific Ocean on 17 April 1970 at 18:07:41 UT (1:07:41 p.m. EST) after a
mission elapsed time of 142 hrs, 54 mins, 41 secs. The splashdown point
was 21 deg 38 min S, 165 deg 22 min W, SE of American Samoa and 6.5 km
(4 mi) from the recovery ship USS Iwo Jima.
The spacecraft was the second of the Apollo H-series. The purposes of
the mission were (1) to explore the hilly upland Fra Mauro region of the
moon, (2) to perform selenological inspection, survey, and sampling of
material in the Fra Mauro formation, (3) to deploy and activate an
Apollo lunar surface experiments package (ALSEP), (4) to further develop
man's capability to work in the lunar environment, and (5) to obtain
photographs of candidate lunar exploration sites. These goals were to be
carried out from a near-circular lunar orbit and on the lunar surface at
3 deg S latitude, 17 deg W longitude. Although the planned mission
objectives were not realized, a limited amount of photographic data was
obtained. Lovell was a Navy captain on his fourth spaceflight (he'd
flown previously on Gemini 7, Gemini 12, and Apollo 8), Haise and
Swigert were both civilians on their first spaceflights. The backup crew
was John Young, Charles Duke, and John Swigert (who replaced Thomas
Mattingly on the prime crew after the crew was exposed to German
measles). The Apollo 13 Command Module "Odyssey" is now at the
Kansas Cosmosphere and Space Center, Hutchinson, Kansas. It was
originally on display at the Musee de l'Air, Paris, France.
Spacecraft and Subsystems
As the name implies, the Command and Service Module (CSM) was
comprised of two distinct units: the Command Module (CM), which housed
the crew, spacecraft operations systems, and re-entry equipment, and the
Service Module (SM) which carried most of the consumables (oxygen,
water, helium, fuel cells, and fuel) and the main propulsion system. The
total length of the two modules attached was 11.0 meters with a maximum
diameter of 3.9 meters. Block II CSM's were used for all the crewed
Apollo missions. The Apollo 13 CSM mass of 28,881 kg was the launch mass
including propellants and expendables, of this the Command Module (CM
109) had a mass of 5703 kg and the Service Module (SM 109) 23,178 kg.
Telecommunications included voice, television, data, and tracking and
ranging subsystems for communications between astronauts, CM, LM, and
Earth. Voice contact was provided by an S-band uplink and downlink
system. Tracking was done through a unified S-band transponder. A high
gain steerable S-band antenna consisting of four 79-cm diameter
parabolic dishes was mounted on a folding boom at the aft end of the SM.
Two VHF scimitar antennas were also mounted on the SM. There was also a
VHF recovery beacon mounted in the CM. The CSM environmental control
system regulated cabin atmosphere, pressure, temperature, carbon
dioxide, odors, particles, and ventilation and controlled the
temperature range of the electronic equipment.
Command Module
The CM was a conical pressure vessel with a maximum diameter of 3.9 m
at its base and a height of 3.65 m. It was made of an aluminum honeycomb
sandwhich bonded between sheet aluminum alloy. The base of the CM
consisted of a heat shield made of brazed stainless steel honeycomb
filled with a phenolic epoxy resin as an ablative material and varied in
thickness from 1.8 to 6.9 cm. At the tip of the cone was a hatch and
docking assembly designed to mate with the lunar module. The CM was
divided into three compartments. The forward compartment in the nose of
the cone held the three 25.4 m diameter main parachutes, two 5 m drogue
parachutes, and pilot mortar chutes for Earth landing. The aft
compartment was situated around the base of the CM and contained
propellant tanks, reaction control engines, wiring, and plumbing. The
crew compartment comprised most of the volume of the CM, approximately
6.17 cubic meters of space. Three astronaut couches were lined up facing
forward in the center of the compartment. A large access hatch was
situated above the center couch. A short access tunnel led to the
docking hatch in the CM nose. The crew compartment held the controls,
displays, navigation equipment and other systems used by the astronauts.
The CM had five windows: one in the access hatch, one next to each
astronaut in the two outer seats, and two forward-facing rendezvous
windows. Five silver/zinc-oxide batteries provided power after the CM
and SM detached, three for re-entry and after landing and two for
vehicle separation and parachute deployment. The CM had twelve 420 N
nitrogen tetroxide/hydrazine reaction control thrusters. The CM provided
the re-entry capability at the end of the mission after separation from
the Service Module.
Service Module
The SM was a cylinder 3.9 meters in diameter and 7.6 m long which was
attached to the back of the CM. The outer skin of the SM was formed of
2.5 cm thick aluminum honeycomb panels. The interior was divided by
milled aluminum radial beams into six sections around a central
cylinder. At the back of the SM mounted in the central cylinder was a
gimbal mounted re-startable hypergolic liquid propellant 91,000 N engine
and cone shaped engine nozzle. Attitude control was provided by four
identical banks of four 450 N reaction control thrusters each spaced 90
degrees apart around the forward part of the SM. The six sections of the
SM held three 31-cell hydrogen oxygen fuel cells which provided 28
volts, two cryogenic oxygen and two cryogenic hydrogen tanks, four tanks
for the main propulsion engine, two for fuel and two for oxidizer, and
the subsystems the main propulsion unit. Two helium tanks were mounted
in the central cylinder. Electrical power system radiators were at the
top of the cylinder and environmental control radiator panels spaced
around the bottom.
Apollo Program
The Apollo program included a large number of uncrewed test missions
and 12 crewed missions: three Earth orbiting missions (Apollo 7, 9 and
Apollo-Soyuz), two lunar orbiting missions (Apollo 8 and 10), a lunar
swingby (Apollo 13), and six Moon landing missions (Apollo 11, 12, 14,
15, 16, and 17). Two astronauts from each of these six missions walked
on the Moon (Neil Armstrong, Edwin Aldrin, Charles Conrad, Alan Bean,
Alan Shepard, Edgar Mitchell, David Scott, James Irwin, John Young,
Charles Duke, Gene Cernan, and Harrison Schmitt), the only humans to
have set foot on another solar system body. Total funding for the Apollo
program was approximately $20,443,600,000.
Alternate Names
- Odyssey
- Apollo 13 CSM
- CSM-109
- 04371
Facts in Brief
Launch Date: 1970-04-11
Launch Vehicle: Saturn 5
Launch Site: Cape Canaveral, United States
Mass: 28945.0 kg
Funding Agency
- NASA-Office of Manned Space Flight (United States)
Disciplines
- Human Crew
- Planetary Science
![[Apollo CSM diagram]](http://nssdc.gsfc.nasa.gov/image/spacecraft/apollo_csm_diagram.gif)
Diagram of the Apollo CSM
