Apollo 5
Encyclopedia
Apollo 5 was the first unmanned flight of the Apollo Lunar Module
, which would later carry astronaut
s to the lunar surface. It lifted off on January 22, 1968 with a Saturn IB
rocket.
able rocket engine
fired in space.
The mission also performed a "fire in the hole" test (as depicted in the mission's insignia) in which the ascent stage engine would be fired while still attached to the descent stage. This was intended to simulate a landing abort during descent to the lunar surface.
As with Apollo 4
, this flight experienced long delays. The primary cause of this was the Lunar Module, which was well behind schedule. Some of the delay could be attributed to lack of experience in building a manned spacecraft to land on the Moon.
The first unmanned launch was originally planned in April 1967, requiring delivery at the Cape around September 1966. But delays kept occurring. Although the Lunar Module was fully designed, there was trouble fabricating the custom made parts. The engines were also having problems. The descent engine was not burning smoothly, and the ascent engine was having fabrication and welding difficulties.
In the end these problems were overcome, but it took several months and it was not until June 23, 1967 that the Lunar Module arrived at the Cape on board Aero Spacelines
' Super Guppy. After four months of tests and repair the Lunar Module was mated to the launch vehicle on November 19.
On December 17, 1967, a LM test failed in the Grumman ascent stage manufacturing plant. A window in LM-5 (Apollo 11's LM Eagle) shattered during its initial cabin pressurization test, designed to pressurize the cabin to 39 kilopascals (5.7 lbf/in2). Both inner and outer windows and the acrylic glass
cover of the right-hand window shattered when the pressure reached 35 kPa (5.1 lbf/in2).
On December 28, 1967 a decision was made to replace the glass windows in LM-1 with aluminum plates as a precaution against a failure in flight similar to the one that occurred on LM-5 in testing.
The launch vehicle for Apollo 5 was the Saturn IB
, a smaller rocket than the Saturn V
but capable of launching an Apollo spacecraft
into Earth orbit. The Saturn IB SA-204 used on Apollo 5 was the one originally intended for Apollo 1
. It had been undamaged in the fire at Launch Complex 34
and was reassembled at Launch Complex 37B for the Apollo 5 launch.
The windows of LM-1 were replaced before the flight with solid aluminum plates. To hasten delivery, it was decided to do without the Lunar Module's legs. Without a crew or CSM
, there was no need for a launch escape system
. As a consequence the assembled rocket was 55 metres (180.4 ft) tall, compared to the usual CSM stack height of 68 metres (223.1 ft).
On January 22, 1968, Apollo 5 lifted off just before sunset. The Saturn IB worked perfectly, inserting the second stage and LM into a 163 x 222 km orbit. The nose cone was jettisoned and after a coast of 43 minutes 52 seconds, the LM separated from its adapter, with a 167 x 222 km orbit. After two orbits, the first planned 39 second descent engine burn was started, but aborted by the onboard guidance computer after only 4 seconds. Shortly before launch there was a suspected fuel leak and a decision was made to delay arming the engine until the time of ignition.
This change had increased the time required for the propellant tanks to pressurize and thrust to build to the required level.
The ground controllers moved to an alternate plan to fire the descent engine manually two more times. They then performed the "fire in the hole" test and another ascent engine burn.
After 11 hours and 10 minutes the test was over, and control of the two stages was terminated. The stages were left in a low enough orbit that atmospheric drag would soon cause their orbits to decay and re-enter the atmosphere. The ascent stage (1968-007A) re-entered on January 24 and burned up; the descent stage (1968-007B) re-entered on February 12, falling into the Pacific several hundred kilometers southwest of Guam
.
Despite the descent engine programming error, NASA deemed the mission a success in demonstrating the LM systems, and a second unmanned flight test using LM-2 was canceled. LM-3 was cleared for the first manned LM flight, which occurred on Apollo 9
.
Apollo Lunar Module
The Apollo Lunar Module was the lander portion of the Apollo spacecraft built for the US Apollo program by Grumman to carry a crew of two from lunar orbit to the surface and back...
, which would later carry astronaut
Astronaut
An astronaut or cosmonaut is a person trained by a human spaceflight program to command, pilot, or serve as a crew member of a spacecraft....
s to the lunar surface. It lifted off on January 22, 1968 with a Saturn IB
Saturn IB
The Saturn IB was an American launch vehicle commissioned by the National Aeronautics and Space Administration for use in the Apollo program...
rocket.
Objectives
The Apollo 5 mission tested the Lunar Module in a space environment, in particular its descent and ascent engine systems, and its ability to separate the ascent and descent stages. The descent engine would become the first throttleThrottle
A throttle is the mechanism by which the flow of a fluid is managed by constriction or obstruction. An engine's power can be increased or decreased by the restriction of inlet gases , but usually decreased. The term throttle has come to refer, informally and incorrectly, to any mechanism by which...
able rocket engine
Rocket engine
A rocket engine, or simply "rocket", is a jet engineRocket Propulsion Elements; 7th edition- chapter 1 that uses only propellant mass for forming its high speed propulsive jet. Rocket engines are reaction engines and obtain thrust in accordance with Newton's third law...
fired in space.
The mission also performed a "fire in the hole" test (as depicted in the mission's insignia) in which the ascent stage engine would be fired while still attached to the descent stage. This was intended to simulate a landing abort during descent to the lunar surface.
Delays
Apollo 4
Apollo 4, , was the first unmanned test flight of the Saturn V launch vehicle, which was ultimately used by the Apollo program to send the first men to the Moon...
, this flight experienced long delays. The primary cause of this was the Lunar Module, which was well behind schedule. Some of the delay could be attributed to lack of experience in building a manned spacecraft to land on the Moon.
The first unmanned launch was originally planned in April 1967, requiring delivery at the Cape around September 1966. But delays kept occurring. Although the Lunar Module was fully designed, there was trouble fabricating the custom made parts. The engines were also having problems. The descent engine was not burning smoothly, and the ascent engine was having fabrication and welding difficulties.
In the end these problems were overcome, but it took several months and it was not until June 23, 1967 that the Lunar Module arrived at the Cape on board Aero Spacelines
Aero Spacelines
Aero Spacelines, Inc. was a United States aircraft manufacturer which made a name for itself by converting Boeing 377 Stratocruisers into the famous Guppy line of airplanes re-engineered solely for transporting over-sized cargo.- History :...
' Super Guppy. After four months of tests and repair the Lunar Module was mated to the launch vehicle on November 19.
On December 17, 1967, a LM test failed in the Grumman ascent stage manufacturing plant. A window in LM-5 (Apollo 11's LM Eagle) shattered during its initial cabin pressurization test, designed to pressurize the cabin to 39 kilopascals (5.7 lbf/in2). Both inner and outer windows and the acrylic glass
Acrylic glass
Poly is a transparent thermoplastic, often used as a light or shatter-resistant alternative to glass. It is sometimes called acrylic glass. Chemically, it is the synthetic polymer of methyl methacrylate...
cover of the right-hand window shattered when the pressure reached 35 kPa (5.1 lbf/in2).
On December 28, 1967 a decision was made to replace the glass windows in LM-1 with aluminum plates as a precaution against a failure in flight similar to the one that occurred on LM-5 in testing.
Flight
Saturn IB
The Saturn IB was an American launch vehicle commissioned by the National Aeronautics and Space Administration for use in the Apollo program...
, a smaller rocket than the Saturn V
Saturn V
The Saturn V was an American human-rated expendable rocket used by NASA's Apollo and Skylab programs from 1967 until 1973. A multistage liquid-fueled launch vehicle, NASA launched 13 Saturn Vs from the Kennedy Space Center, Florida with no loss of crew or payload...
but capable of launching an Apollo spacecraft
Apollo spacecraft
The Apollo spacecraft was composed of five combined parts designed to accomplish the American Apollo program's goal of landing astronauts on the Moon by the end of the 1960s and returning them safely to Earth...
into Earth orbit. The Saturn IB SA-204 used on Apollo 5 was the one originally intended for Apollo 1
Apollo 1
Apollo 1 was scheduled to be the first manned mission of the Apollo manned lunar landing program, with a target launch date of February 21, 1967. A cabin fire during a launch pad test on January 27 at Launch Pad 34 at Cape Canaveral killed all three crew members: Command Pilot Virgil "Gus"...
. It had been undamaged in the fire at Launch Complex 34
Cape Canaveral Air Force Station Launch Complex 34
Cape Canaveral Air Force Station Launch Complex 34 is a launch site on Cape Canaveral, Florida. LC-34 and its twin to the north, LC-37, were used by NASA as part of the Apollo Program to launch Saturn I and IB rockets from 1961 through 1968...
and was reassembled at Launch Complex 37B for the Apollo 5 launch.
The windows of LM-1 were replaced before the flight with solid aluminum plates. To hasten delivery, it was decided to do without the Lunar Module's legs. Without a crew or CSM
Apollo Command/Service Module
The Command/Service Module was one of two spacecraft, along with the Lunar Module, used for the United States Apollo program which landed astronauts on the Moon. It was built for NASA by North American Aviation...
, there was no need for a launch escape system
Launch escape system
A Launch Escape System is a top-mounted rocket connected to the crew module of a crewed spacecraft and used to quickly separate the crew module from the rest of the rocket in case of emergency. Since the escape rockets are above the crew module, an LES typically uses separate nozzles which are...
. As a consequence the assembled rocket was 55 metres (180.4 ft) tall, compared to the usual CSM stack height of 68 metres (223.1 ft).
On January 22, 1968, Apollo 5 lifted off just before sunset. The Saturn IB worked perfectly, inserting the second stage and LM into a 163 x 222 km orbit. The nose cone was jettisoned and after a coast of 43 minutes 52 seconds, the LM separated from its adapter, with a 167 x 222 km orbit. After two orbits, the first planned 39 second descent engine burn was started, but aborted by the onboard guidance computer after only 4 seconds. Shortly before launch there was a suspected fuel leak and a decision was made to delay arming the engine until the time of ignition.
This change had increased the time required for the propellant tanks to pressurize and thrust to build to the required level.
The ground controllers moved to an alternate plan to fire the descent engine manually two more times. They then performed the "fire in the hole" test and another ascent engine burn.
After 11 hours and 10 minutes the test was over, and control of the two stages was terminated. The stages were left in a low enough orbit that atmospheric drag would soon cause their orbits to decay and re-enter the atmosphere. The ascent stage (1968-007A) re-entered on January 24 and burned up; the descent stage (1968-007B) re-entered on February 12, falling into the Pacific several hundred kilometers southwest of Guam
Guam
Guam is an organized, unincorporated territory of the United States located in the western Pacific Ocean. It is one of five U.S. territories with an established civilian government. Guam is listed as one of 16 Non-Self-Governing Territories by the Special Committee on Decolonization of the United...
.
Despite the descent engine programming error, NASA deemed the mission a success in demonstrating the LM systems, and a second unmanned flight test using LM-2 was canceled. LM-3 was cleared for the first manned LM flight, which occurred on Apollo 9
Apollo 9
Apollo 9, the third manned mission in the American Apollo space program, was the first flight of the Command/Service Module with the Lunar Module...
.