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### ali Qazi

News -GplayFC is the only legitimate website where you can get a free $25 Google Play Store code.

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### Mahmud abdullah al

Discussion -i am 27, i want to study aeronautical engineering, it will take 5 more years to finish, so when i finish i will be 32 or 33, i am willing to sacrifice my time and effort, but is it too late? i mean one of my friend told me that, companies that hire engineers, they prefer younger people, and will it be very difficult to find job for someone who finishes his study at 33, what is your opinion about it?

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ok, i got it, thanks a lot

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### In Compliance Magazine

News -We are happy to have found this community! Check out our aerospace engineering news at the link below. We're always looking for new stories, so please let us know if there are new topics we should cover.

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### Duroair

Discussion -Duroair Air Filtration systems are straightforward to set up as shown in the video below.

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تسلم

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### Steven Swaks

Discussion -Photographer Ralph Mirebs visited an abandoned hangar near the Baikonur Cosmodrome in Kazakhstan. It houses two shuttles (shown) that were part of the ill-fated Buran shuttle programme.

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### sojon sikdar

News -Boarding aircraft is probably one of the most tedious and stressful parts of air travel, but transport designer, Urgur Ipek, of Ugur Ipek Design, Germany, believes it’s all due to the impractical shape of cabin interiors. Instead of the traditional uniform cylinder, he proposes that boarding would be much simpler...

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### Veronica Wilson

Discussion -We cordially invite you to the 3rd International Conference and Exhibition on Mechanical and Aerospace Engineering which is going to be held at San Francisco during October 05-07,2015.

https://plus.google.com/u/0/b/105761497968904457133/events/c9fi7li54mbdb9p5btok91l8dh8

https://plus.google.com/u/0/b/105761497968904457133/events/c9fi7li54mbdb9p5btok91l8dh8

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### Stephen Rider

Propulsion -Hi, I'm trying to understand interplanetary transfer orbits a bit better and I think I'm understanding the basics of how you go about solving Hohmann orbits. I have two questions:

1) What if the other end of the Hohmann is a L point? I know that you can have halo orbits around them, so I'm not understanding what values to plug in yet.

2) How do you move ahead or behind in the same orbit? I understand that it's (basically) some sort of an ellipse that comes into play as soon as you exit the sphere of influence...but I have no clue how to start solving it.

Thanks for any suggestions and I hope everyone is having a great day!

1) What if the other end of the Hohmann is a L point? I know that you can have halo orbits around them, so I'm not understanding what values to plug in yet.

2) How do you move ahead or behind in the same orbit? I understand that it's (basically) some sort of an ellipse that comes into play as soon as you exit the sphere of influence...but I have no clue how to start solving it.

Thanks for any suggestions and I hope everyone is having a great day!

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1- Most of the manoeuvres are coplanar orbits '' Including The Hohmann transfer''.

2- ''Your what (if) question: L point is one one the Lagrange points., however your question is more related to what we call the restricted three body problem, in this case we consider a system of three bodies, such as sun, earth and a space craft '' satellite for example'', or moon, earth, and the space craft. In this case the mass of the space craft is astonishingly small compared to the primary masses ( earth and moon, or sun and earth). Here we need to find the equations of the motion of the secondary mass (space craft) relative to the primary masses (sun and earth, or earth and moon), establishing the position vector of the secondary mass relative to primary masses.

2.1: Lagrange point: For the fact that the equations of the space craft have no closed form of analytical solution, so one can use them to find the location of equilibrium points, these point are the location in space where the secondary mass would have zero velocity and zero acceleration, which means the secondary mass appear permanently at rest relative to earth and moon system , or sun and earth system...So here one needs to find the equilibrium points ( also called liberation points, or Lagrange points). For example in the earth-moon system the five Lagrange points orbit the earth with the same period as the moon. Can you tell me why?

Important remarks about what we call Lagrange points,or equilibrium points:

2.2 if an equilibrium point is stable, then a small mass occupying that point will tend to return to that point if nudged out of position. The perturbation result in a small oscillation(orbit)about the equilibrium point. Thus object can be placed in a small orbit called (halo orbits) around stable equilibrium points without requiring much in the way of station keeping. On the other hand, if a body located at an unstable equilibrium point is only slightly perturbed, it will oscillate in a divergent fashion, drifting eventually completely away from that point. It turns out that Lagrange point L1, L2, and L3 on the apse line are unstable, whereas L4, and L5~~60 degrees ahead of v and behind the moon in its orbit~~ are stable. However L4, and L5 are destabilized by the sun's gravity.......

For example Solar observation spacecraft have been placed in halo orbit around L1 point of the sun-earth system. L1 lies about 1.5 *10^6 kilometers from the earth and outside the earth's magnetosphere.Example of such mission The international Sun-Earth explorer 3 (ISSE-3) launched in August 1978; the Solar and Heliocentric Observatory ( SOHO) launched in 1995, and the advanced composition explorer (ACE) launched in August 1997.

2.4: I think one needs to do some reading about Halo orbit....and the restricted three body problem, (Circular and elliptic).

2.5: I will suggest to read the following: Non-hohmann transfer with a common apse line . There are a lot interesting books.........

2- ''Your what (if) question: L point is one one the Lagrange points., however your question is more related to what we call the restricted three body problem, in this case we consider a system of three bodies, such as sun, earth and a space craft '' satellite for example'', or moon, earth, and the space craft. In this case the mass of the space craft is astonishingly small compared to the primary masses ( earth and moon, or sun and earth). Here we need to find the equations of the motion of the secondary mass (space craft) relative to the primary masses (sun and earth, or earth and moon), establishing the position vector of the secondary mass relative to primary masses.

2.1: Lagrange point: For the fact that the equations of the space craft have no closed form of analytical solution, so one can use them to find the location of equilibrium points, these point are the location in space where the secondary mass would have zero velocity and zero acceleration, which means the secondary mass appear permanently at rest relative to earth and moon system , or sun and earth system...So here one needs to find the equilibrium points ( also called liberation points, or Lagrange points). For example in the earth-moon system the five Lagrange points orbit the earth with the same period as the moon. Can you tell me why?

Important remarks about what we call Lagrange points,or equilibrium points:

2.2 if an equilibrium point is stable, then a small mass occupying that point will tend to return to that point if nudged out of position. The perturbation result in a small oscillation(orbit)about the equilibrium point. Thus object can be placed in a small orbit called (halo orbits) around stable equilibrium points without requiring much in the way of station keeping. On the other hand, if a body located at an unstable equilibrium point is only slightly perturbed, it will oscillate in a divergent fashion, drifting eventually completely away from that point. It turns out that Lagrange point L1, L2, and L3 on the apse line are unstable, whereas L4, and L5

For example Solar observation spacecraft have been placed in halo orbit around L1 point of the sun-earth system. L1 lies about 1.5 *10^6 kilometers from the earth and outside the earth's magnetosphere.Example of such mission The international Sun-Earth explorer 3 (ISSE-3) launched in August 1978; the Solar and Heliocentric Observatory ( SOHO) launched in 1995, and the advanced composition explorer (ACE) launched in August 1997.

2.4: I think one needs to do some reading about Halo orbit....and the restricted three body problem, (Circular and elliptic).

2.5: I will suggest to read the following: Non-hohmann transfer with a common apse line . There are a lot interesting books.........

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### About this community

All about Aerospace & Aeronautical Engineering Worldwide. Welcome Engineers, AvGeeks & SpaceGeeks

### In Compliance Magazine

News -Learn about the tools New Horizons is carrying for observing Pluto's atmosphere

NASA’s unmanned spacecraft New Horizons is less than two weeks away from a historic flyby of Pluto and its moons. It is the longest, farthest, and fastest space mission ever. After nine years, thre...

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+MMaurice Bendou spare time is hard to come by! Subscribe (for free) so you can catch up on the magazine whenever you find a moment. Or sign up for the newsletters if you only have time to check out a few articles each week. http://incompliancemag.com/subscribe/print-digital/

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### Robert Henderson

Propulsion -Spike application.

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2 comments

I am thinking scale back hyper sonic intake .

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### Francisco Pellecer

Discussion -Check Out The Best Engineer Funny Shirts! Make, Design Or Customize Yours, No Minimum Order!

Click The Link Below:

http://bestteeshirts.net/shop/category/Engineer-Shirts?c=1258592&ctype=0

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### vasudeva rayasam

News -I flew a Boeing 737 from Hong Kong to Macau..................................on a simulator

flight experience Singapore, just do it..!!

flight experience Singapore, just do it..!!

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Simulator this was a feat.

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### Luke Lambert

Discussion -Which is the better reconnaissance plane?

146 votes - votes visible to Public

59%

41%

Fieseler Fi 156 Storch

59%

Aeronca L-3 Grasshopper

41%

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### SunGrist Bible

Aerodynamics and Flight Mechanics -Aerodynamics with Matlab and free open software like octave, scilab, and freemat..

http://www.biblecombibleman.com/TechnicalCorner.html

http://www.biblecombibleman.com/TechnicalCorner.html

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### sojon sikdar

Discussion -After years of design studies and airline surveys, Airbus finally made the decision to go ahead with the € 8.8 billion A380 project in 1999, the final budget settling at about € 12 billion. The design strategy was carefully crafted and by being very large the A380 achieves much...

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