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Why did the S-IV-B refer to “jettisonâ€ing its ullage?
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This is based on a recent question about S-IV-B ullage motor shutoff timing, specifically something found in the Technical Information Summary AS-501, page 15:
Ullage Jettison ~ 532.
But why "JETTISON" (not "ullage engines on or off")? What does it mean?
apollo-program terminology ullage
edited 4 hours ago
Nathan Tuggy
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asked 5 hours ago
A. P. Heiler
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up vote
2
down vote
favorite
This is based on a recent question about S-IV-B ullage motor shutoff timing, specifically something found in the Technical Information Summary AS-501, page 15:
Ullage Jettison ~ 532.
But why "JETTISON" (not "ullage engines on or off")? What does it mean?
apollo-program terminology ullage
edited 4 hours ago
Nathan Tuggy
3,58542436
asked 5 hours ago
A. P. Heiler
111
New contributor
A. P. Heiler is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
up vote
2
down vote
favorite
up vote
2
down vote
favorite
This is based on a recent question about S-IV-B ullage motor shutoff timing, specifically something found in the Technical Information Summary AS-501, page 15:
Ullage Jettison ~ 532.
But why "JETTISON" (not "ullage engines on or off")? What does it mean?
apollo-program terminology ullage
edited 4 hours ago
Nathan Tuggy
3,58542436
asked 5 hours ago
A. P. Heiler
111
New contributor
A. P. Heiler is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
This is based on a recent question about S-IV-B ullage motor shutoff timing, specifically something found in the Technical Information Summary AS-501, page 15:
Ullage Jettison ~ 532.
But why "JETTISON" (not "ullage engines on or off")? What does it mean?
apollo-program terminology ullage
apollo-program terminology ullage
edited 4 hours ago
Nathan Tuggy
3,58542436
asked 5 hours ago
A. P. Heiler
111
New contributor
A. P. Heiler is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 4 hours ago
Nathan Tuggy
3,58542436
asked 5 hours ago
A. P. Heiler
111
New contributor
A. P. Heiler is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 4 hours ago
Nathan Tuggy
3,58542436
edited 4 hours ago
Nathan Tuggy
3,58542436
edited 4 hours ago
Nathan Tuggy
3,58542436
3,58542436
asked 5 hours ago
A. P. Heiler
111
New contributor
A. P. Heiler is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 5 hours ago
A. P. Heiler
111
asked 5 hours ago
A. P. Heiler
111
111
New contributor
A. P. Heiler is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
A. P. Heiler is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
A. P. Heiler is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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1 Answer
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There are two separate systems for ullage on the S-IVB (500 series only). The first one is used for the first start of the S-IVB during launch. Some information can be found in the AS-503 Saturn V Flight Manual, pages 6-31 and 6-32:
ULLAGE ROCKET SYSTEM
To provide propellant settling and thus ensure stable flow of lox and LH2 during J-2 engine start, the S-IVB stage requires a small acceleration. This acceleration is provided by two ullage rockets.
Each ullage rocket has a single grain, five point star configuration, internal burning, polymerized solid propellant that is case bonded in a 4134 steel case. The propellant weighs approximately 58.8 pounds and burns for 3.8 seconds, developing a thrust of 3390 pounds (175,000 feet, 70 degrees F).
ULLAGE ROCKET JETTISON SYSTEM
To reduce weight, the ullage rockets and their fairings are jettisoned after J-2 engine start.
For ullage thrust after orbital insertion and before TLI the S-IVB uses two ullage thrusters that are part of the Auxiliary Propulsion System. These thrusters are not jettisoned and they draw propellant from the same source as the attitude control thrusters. From pages 6-21 and 6-22 of the document linked above:
AUXILIARY PROPULSION SYSTEM
The S-IVB auxiliary propulsion system provides three axis stage attitude control and main stage propellant control during coast flight.
Nitrogen tetroxide (N2O4) is used as an oxidizer and monomethylhydrazine (MMH) is used as fuel for these engines. The 150-pound thrust engines utilize eight control vales (four for fuel, four for oxidize) in a fail safe series parallel arrangement. The 70-pound ullage engine uses only single valves on both the fuel and oxidizer lines.
APS Operation
Two of the three 150-pound thrust engines in each module control roll and yaw, while one controls pitch. The 70-pound thrust engine in each module is used to settle the propellants in the propellant tanks. Just prior to J-2 engine restart, propellant control is accomplished by firing the 70-pound thrust engines.
answered 4 hours ago
indy91
43133
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
3
down vote
There are two separate systems for ullage on the S-IVB (500 series only). The first one is used for the first start of the S-IVB during launch. Some information can be found in the AS-503 Saturn V Flight Manual, pages 6-31 and 6-32:
ULLAGE ROCKET SYSTEM
To provide propellant settling and thus ensure stable flow of lox and LH2 during J-2 engine start, the S-IVB stage requires a small acceleration. This acceleration is provided by two ullage rockets.
Each ullage rocket has a single grain, five point star configuration, internal burning, polymerized solid propellant that is case bonded in a 4134 steel case. The propellant weighs approximately 58.8 pounds and burns for 3.8 seconds, developing a thrust of 3390 pounds (175,000 feet, 70 degrees F).
ULLAGE ROCKET JETTISON SYSTEM
To reduce weight, the ullage rockets and their fairings are jettisoned after J-2 engine start.
For ullage thrust after orbital insertion and before TLI the S-IVB uses two ullage thrusters that are part of the Auxiliary Propulsion System. These thrusters are not jettisoned and they draw propellant from the same source as the attitude control thrusters. From pages 6-21 and 6-22 of the document linked above:
AUXILIARY PROPULSION SYSTEM
The S-IVB auxiliary propulsion system provides three axis stage attitude control and main stage propellant control during coast flight.
Nitrogen tetroxide (N2O4) is used as an oxidizer and monomethylhydrazine (MMH) is used as fuel for these engines. The 150-pound thrust engines utilize eight control vales (four for fuel, four for oxidize) in a fail safe series parallel arrangement. The 70-pound ullage engine uses only single valves on both the fuel and oxidizer lines.
APS Operation
Two of the three 150-pound thrust engines in each module control roll and yaw, while one controls pitch. The 70-pound thrust engine in each module is used to settle the propellants in the propellant tanks. Just prior to J-2 engine restart, propellant control is accomplished by firing the 70-pound thrust engines.
answered 4 hours ago
indy91
43133
add a comment |Â
up vote
3
down vote
There are two separate systems for ullage on the S-IVB (500 series only). The first one is used for the first start of the S-IVB during launch. Some information can be found in the AS-503 Saturn V Flight Manual, pages 6-31 and 6-32:
ULLAGE ROCKET SYSTEM
To provide propellant settling and thus ensure stable flow of lox and LH2 during J-2 engine start, the S-IVB stage requires a small acceleration. This acceleration is provided by two ullage rockets.
Each ullage rocket has a single grain, five point star configuration, internal burning, polymerized solid propellant that is case bonded in a 4134 steel case. The propellant weighs approximately 58.8 pounds and burns for 3.8 seconds, developing a thrust of 3390 pounds (175,000 feet, 70 degrees F).
ULLAGE ROCKET JETTISON SYSTEM
To reduce weight, the ullage rockets and their fairings are jettisoned after J-2 engine start.
For ullage thrust after orbital insertion and before TLI the S-IVB uses two ullage thrusters that are part of the Auxiliary Propulsion System. These thrusters are not jettisoned and they draw propellant from the same source as the attitude control thrusters. From pages 6-21 and 6-22 of the document linked above:
AUXILIARY PROPULSION SYSTEM
The S-IVB auxiliary propulsion system provides three axis stage attitude control and main stage propellant control during coast flight.
Nitrogen tetroxide (N2O4) is used as an oxidizer and monomethylhydrazine (MMH) is used as fuel for these engines. The 150-pound thrust engines utilize eight control vales (four for fuel, four for oxidize) in a fail safe series parallel arrangement. The 70-pound ullage engine uses only single valves on both the fuel and oxidizer lines.
APS Operation
Two of the three 150-pound thrust engines in each module control roll and yaw, while one controls pitch. The 70-pound thrust engine in each module is used to settle the propellants in the propellant tanks. Just prior to J-2 engine restart, propellant control is accomplished by firing the 70-pound thrust engines.
answered 4 hours ago
indy91
43133
add a comment |Â
up vote
3
down vote
up vote
3
down vote
There are two separate systems for ullage on the S-IVB (500 series only). The first one is used for the first start of the S-IVB during launch. Some information can be found in the AS-503 Saturn V Flight Manual, pages 6-31 and 6-32:
ULLAGE ROCKET SYSTEM
To provide propellant settling and thus ensure stable flow of lox and LH2 during J-2 engine start, the S-IVB stage requires a small acceleration. This acceleration is provided by two ullage rockets.
Each ullage rocket has a single grain, five point star configuration, internal burning, polymerized solid propellant that is case bonded in a 4134 steel case. The propellant weighs approximately 58.8 pounds and burns for 3.8 seconds, developing a thrust of 3390 pounds (175,000 feet, 70 degrees F).
ULLAGE ROCKET JETTISON SYSTEM
To reduce weight, the ullage rockets and their fairings are jettisoned after J-2 engine start.
For ullage thrust after orbital insertion and before TLI the S-IVB uses two ullage thrusters that are part of the Auxiliary Propulsion System. These thrusters are not jettisoned and they draw propellant from the same source as the attitude control thrusters. From pages 6-21 and 6-22 of the document linked above:
AUXILIARY PROPULSION SYSTEM
The S-IVB auxiliary propulsion system provides three axis stage attitude control and main stage propellant control during coast flight.
Nitrogen tetroxide (N2O4) is used as an oxidizer and monomethylhydrazine (MMH) is used as fuel for these engines. The 150-pound thrust engines utilize eight control vales (four for fuel, four for oxidize) in a fail safe series parallel arrangement. The 70-pound ullage engine uses only single valves on both the fuel and oxidizer lines.
APS Operation
Two of the three 150-pound thrust engines in each module control roll and yaw, while one controls pitch. The 70-pound thrust engine in each module is used to settle the propellants in the propellant tanks. Just prior to J-2 engine restart, propellant control is accomplished by firing the 70-pound thrust engines.
answered 4 hours ago
indy91
43133
There are two separate systems for ullage on the S-IVB (500 series only). The first one is used for the first start of the S-IVB during launch. Some information can be found in the AS-503 Saturn V Flight Manual, pages 6-31 and 6-32:
ULLAGE ROCKET SYSTEM
To provide propellant settling and thus ensure stable flow of lox and LH2 during J-2 engine start, the S-IVB stage requires a small acceleration. This acceleration is provided by two ullage rockets.
Each ullage rocket has a single grain, five point star configuration, internal burning, polymerized solid propellant that is case bonded in a 4134 steel case. The propellant weighs approximately 58.8 pounds and burns for 3.8 seconds, developing a thrust of 3390 pounds (175,000 feet, 70 degrees F).
ULLAGE ROCKET JETTISON SYSTEM
To reduce weight, the ullage rockets and their fairings are jettisoned after J-2 engine start.
For ullage thrust after orbital insertion and before TLI the S-IVB uses two ullage thrusters that are part of the Auxiliary Propulsion System. These thrusters are not jettisoned and they draw propellant from the same source as the attitude control thrusters. From pages 6-21 and 6-22 of the document linked above:
AUXILIARY PROPULSION SYSTEM
The S-IVB auxiliary propulsion system provides three axis stage attitude control and main stage propellant control during coast flight.
Nitrogen tetroxide (N2O4) is used as an oxidizer and monomethylhydrazine (MMH) is used as fuel for these engines. The 150-pound thrust engines utilize eight control vales (four for fuel, four for oxidize) in a fail safe series parallel arrangement. The 70-pound ullage engine uses only single valves on both the fuel and oxidizer lines.
APS Operation
Two of the three 150-pound thrust engines in each module control roll and yaw, while one controls pitch. The 70-pound thrust engine in each module is used to settle the propellants in the propellant tanks. Just prior to J-2 engine restart, propellant control is accomplished by firing the 70-pound thrust engines.
answered 4 hours ago
indy91
43133
answered 4 hours ago
indy91
43133
answered 4 hours ago
indy91
43133
answered 4 hours ago
indy91
43133
43133
add a comment |Â
add a comment |Â
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A. P. Heiler is a new contributor. Be nice, and check out our Code of Conduct.
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