Calculating Specific Mechanical Energy in a spacecraft

In summary, the conversation is about a student struggling with their math skills and seeking help with a specific question regarding the specific mechanical energy of an orbit with a semimajor axis of 42,160km. The student attempted to use a formula but got a different answer than the one provided in the book. They are asking for assistance in finding the error in their formula.
  • #1
spacemike1
5
0

Homework Statement



My math is horrible and I'm in an orbital mechanics class which I'm way over my head...my question is...

"What is the specific mechanical energy, e, of an orbit with a semimajor axis of 42,160km"


Homework Equations



I used a formula that took

-3.986x10^5 / 2x 42160

to get the SME.


The Attempt at a Solution



The book says I should get -4.73 km^2/s^2

I get -3.36 x 10^10 ...I'm way off

Can you help me what I'm doing wrong in my formula?
 
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  • #2
I worked on this and found a formula in the book to solve this. I used

a= -u/2e
 

FAQ: Calculating Specific Mechanical Energy in a spacecraft

What is specific mechanical energy in a spacecraft?

Specific mechanical energy in a spacecraft is a measure of the total energy of the spacecraft per unit mass. It takes into account both the kinetic energy and the potential energy of the spacecraft in its current position and velocity.

Why is it important to calculate specific mechanical energy in a spacecraft?

Calculating specific mechanical energy is important because it helps engineers and scientists understand the energy requirements and limitations of a spacecraft. It also allows for efficient and precise trajectory planning and control.

How is specific mechanical energy calculated in a spacecraft?

The specific mechanical energy of a spacecraft can be calculated by adding the kinetic energy (1/2 x mass x velocity^2) and the potential energy (mass x gravitational constant x height) of the spacecraft, divided by its mass.

What units are used to measure specific mechanical energy in a spacecraft?

Specific mechanical energy is typically measured in units of Joules per kilogram (J/kg) in the International System of Units (SI).

Can specific mechanical energy in a spacecraft change during a mission?

Yes, specific mechanical energy in a spacecraft can change during a mission due to factors such as changes in speed, altitude, or gravitational fields. This is why it is important to continuously monitor and calculate the specific mechanical energy to ensure the spacecraft is functioning as intended.

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