Why should the roll program position the shuttle's nose to the east?











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The roll program occurred during a shuttle launch for the following reasons:



(...)
Orienting the shuttle more parallel toward the ground with the nose to the east.


But why east?










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  • 2




    Possible duplicate of How does the roll maneuver allow more mass to be lifted into orbit?
    – SF.
    Dec 4 at 13:07










  • (long story short: utilizing the speed of rotation of Earth as a part of orbital velocity. This choice of direction sheds some 200-300m/s off the delta-V required to orbit.)
    – SF.
    Dec 4 at 13:09






  • 3




    I disgree with the duplicate topic votes. That topic has some relevant information, but doesn't explain why launches were aimed to the East.
    – Hobbes
    Dec 4 at 13:53















up vote
4
down vote

favorite












The roll program occurred during a shuttle launch for the following reasons:



(...)
Orienting the shuttle more parallel toward the ground with the nose to the east.


But why east?










share|improve this question




















  • 2




    Possible duplicate of How does the roll maneuver allow more mass to be lifted into orbit?
    – SF.
    Dec 4 at 13:07










  • (long story short: utilizing the speed of rotation of Earth as a part of orbital velocity. This choice of direction sheds some 200-300m/s off the delta-V required to orbit.)
    – SF.
    Dec 4 at 13:09






  • 3




    I disgree with the duplicate topic votes. That topic has some relevant information, but doesn't explain why launches were aimed to the East.
    – Hobbes
    Dec 4 at 13:53













up vote
4
down vote

favorite









up vote
4
down vote

favorite











The roll program occurred during a shuttle launch for the following reasons:



(...)
Orienting the shuttle more parallel toward the ground with the nose to the east.


But why east?










share|improve this question















The roll program occurred during a shuttle launch for the following reasons:



(...)
Orienting the shuttle more parallel toward the ground with the nose to the east.


But why east?







launch launch-sequence






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Dec 4 at 17:45









jpaugh

1055




1055










asked Dec 4 at 12:29









Marian Paździoch

1512




1512








  • 2




    Possible duplicate of How does the roll maneuver allow more mass to be lifted into orbit?
    – SF.
    Dec 4 at 13:07










  • (long story short: utilizing the speed of rotation of Earth as a part of orbital velocity. This choice of direction sheds some 200-300m/s off the delta-V required to orbit.)
    – SF.
    Dec 4 at 13:09






  • 3




    I disgree with the duplicate topic votes. That topic has some relevant information, but doesn't explain why launches were aimed to the East.
    – Hobbes
    Dec 4 at 13:53














  • 2




    Possible duplicate of How does the roll maneuver allow more mass to be lifted into orbit?
    – SF.
    Dec 4 at 13:07










  • (long story short: utilizing the speed of rotation of Earth as a part of orbital velocity. This choice of direction sheds some 200-300m/s off the delta-V required to orbit.)
    – SF.
    Dec 4 at 13:09






  • 3




    I disgree with the duplicate topic votes. That topic has some relevant information, but doesn't explain why launches were aimed to the East.
    – Hobbes
    Dec 4 at 13:53








2




2




Possible duplicate of How does the roll maneuver allow more mass to be lifted into orbit?
– SF.
Dec 4 at 13:07




Possible duplicate of How does the roll maneuver allow more mass to be lifted into orbit?
– SF.
Dec 4 at 13:07












(long story short: utilizing the speed of rotation of Earth as a part of orbital velocity. This choice of direction sheds some 200-300m/s off the delta-V required to orbit.)
– SF.
Dec 4 at 13:09




(long story short: utilizing the speed of rotation of Earth as a part of orbital velocity. This choice of direction sheds some 200-300m/s off the delta-V required to orbit.)
– SF.
Dec 4 at 13:09




3




3




I disgree with the duplicate topic votes. That topic has some relevant information, but doesn't explain why launches were aimed to the East.
– Hobbes
Dec 4 at 13:53




I disgree with the duplicate topic votes. That topic has some relevant information, but doesn't explain why launches were aimed to the East.
– Hobbes
Dec 4 at 13:53










1 Answer
1






active

oldest

votes

















up vote
10
down vote













The phrase 'with the nose to the east' is a shorthand. The direction depended on the orbital inclination chosen for the mission.




  • Missions to the ISS have to match the 51.6° inclination of the ISS

  • the possible inclinations are limited by the launch location: from Cape Canaveral, you have to launch over water, so in a direction roughly between North-East and South.


You usually want to launch to the East (as opposed to launching to the West) because of the Earth's rotation to the East. If you launch to the East, you get part of your orbital speed (about 300 m/s on the equator) 'for free'.



The Shuttle needed to perform a roll program to get to the launch inclination: the launch pad is at a fixed angle that usually doesn't match the launch inclination, so you need to change course (preferably just after launch when your speed is low and the energy cost of the maneuver is lowest).






share|improve this answer





















  • So, this is a bit more complicated. If this was all there was to the story, you could must have a yaw program and yaw to the east. In reality, the roll program orients the stack aerodynamically with the comm antennas (on the top of the orbiter) facing down -- a "heads down" ascent. Later in the program, there were plans to do a "heads up" ascent out of Vandenberg, but it never happened.
    – Erik
    yesterday











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
10
down vote













The phrase 'with the nose to the east' is a shorthand. The direction depended on the orbital inclination chosen for the mission.




  • Missions to the ISS have to match the 51.6° inclination of the ISS

  • the possible inclinations are limited by the launch location: from Cape Canaveral, you have to launch over water, so in a direction roughly between North-East and South.


You usually want to launch to the East (as opposed to launching to the West) because of the Earth's rotation to the East. If you launch to the East, you get part of your orbital speed (about 300 m/s on the equator) 'for free'.



The Shuttle needed to perform a roll program to get to the launch inclination: the launch pad is at a fixed angle that usually doesn't match the launch inclination, so you need to change course (preferably just after launch when your speed is low and the energy cost of the maneuver is lowest).






share|improve this answer





















  • So, this is a bit more complicated. If this was all there was to the story, you could must have a yaw program and yaw to the east. In reality, the roll program orients the stack aerodynamically with the comm antennas (on the top of the orbiter) facing down -- a "heads down" ascent. Later in the program, there were plans to do a "heads up" ascent out of Vandenberg, but it never happened.
    – Erik
    yesterday















up vote
10
down vote













The phrase 'with the nose to the east' is a shorthand. The direction depended on the orbital inclination chosen for the mission.




  • Missions to the ISS have to match the 51.6° inclination of the ISS

  • the possible inclinations are limited by the launch location: from Cape Canaveral, you have to launch over water, so in a direction roughly between North-East and South.


You usually want to launch to the East (as opposed to launching to the West) because of the Earth's rotation to the East. If you launch to the East, you get part of your orbital speed (about 300 m/s on the equator) 'for free'.



The Shuttle needed to perform a roll program to get to the launch inclination: the launch pad is at a fixed angle that usually doesn't match the launch inclination, so you need to change course (preferably just after launch when your speed is low and the energy cost of the maneuver is lowest).






share|improve this answer





















  • So, this is a bit more complicated. If this was all there was to the story, you could must have a yaw program and yaw to the east. In reality, the roll program orients the stack aerodynamically with the comm antennas (on the top of the orbiter) facing down -- a "heads down" ascent. Later in the program, there were plans to do a "heads up" ascent out of Vandenberg, but it never happened.
    – Erik
    yesterday













up vote
10
down vote










up vote
10
down vote









The phrase 'with the nose to the east' is a shorthand. The direction depended on the orbital inclination chosen for the mission.




  • Missions to the ISS have to match the 51.6° inclination of the ISS

  • the possible inclinations are limited by the launch location: from Cape Canaveral, you have to launch over water, so in a direction roughly between North-East and South.


You usually want to launch to the East (as opposed to launching to the West) because of the Earth's rotation to the East. If you launch to the East, you get part of your orbital speed (about 300 m/s on the equator) 'for free'.



The Shuttle needed to perform a roll program to get to the launch inclination: the launch pad is at a fixed angle that usually doesn't match the launch inclination, so you need to change course (preferably just after launch when your speed is low and the energy cost of the maneuver is lowest).






share|improve this answer












The phrase 'with the nose to the east' is a shorthand. The direction depended on the orbital inclination chosen for the mission.




  • Missions to the ISS have to match the 51.6° inclination of the ISS

  • the possible inclinations are limited by the launch location: from Cape Canaveral, you have to launch over water, so in a direction roughly between North-East and South.


You usually want to launch to the East (as opposed to launching to the West) because of the Earth's rotation to the East. If you launch to the East, you get part of your orbital speed (about 300 m/s on the equator) 'for free'.



The Shuttle needed to perform a roll program to get to the launch inclination: the launch pad is at a fixed angle that usually doesn't match the launch inclination, so you need to change course (preferably just after launch when your speed is low and the energy cost of the maneuver is lowest).







share|improve this answer












share|improve this answer



share|improve this answer










answered Dec 4 at 14:05









Hobbes

84.7k2238383




84.7k2238383












  • So, this is a bit more complicated. If this was all there was to the story, you could must have a yaw program and yaw to the east. In reality, the roll program orients the stack aerodynamically with the comm antennas (on the top of the orbiter) facing down -- a "heads down" ascent. Later in the program, there were plans to do a "heads up" ascent out of Vandenberg, but it never happened.
    – Erik
    yesterday


















  • So, this is a bit more complicated. If this was all there was to the story, you could must have a yaw program and yaw to the east. In reality, the roll program orients the stack aerodynamically with the comm antennas (on the top of the orbiter) facing down -- a "heads down" ascent. Later in the program, there were plans to do a "heads up" ascent out of Vandenberg, but it never happened.
    – Erik
    yesterday
















So, this is a bit more complicated. If this was all there was to the story, you could must have a yaw program and yaw to the east. In reality, the roll program orients the stack aerodynamically with the comm antennas (on the top of the orbiter) facing down -- a "heads down" ascent. Later in the program, there were plans to do a "heads up" ascent out of Vandenberg, but it never happened.
– Erik
yesterday




So, this is a bit more complicated. If this was all there was to the story, you could must have a yaw program and yaw to the east. In reality, the roll program orients the stack aerodynamically with the comm antennas (on the top of the orbiter) facing down -- a "heads down" ascent. Later in the program, there were plans to do a "heads up" ascent out of Vandenberg, but it never happened.
– Erik
yesterday


















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