- #1

- 59

- 0

- Thread starter skiboka33
- Start date

- #1

- 59

- 0

- #2

- 3,598

- 1,434

You can solve for the total energy of your probe in this new orbit, and you can solve for the total energy in the original orbit. From this you can solve for the energy difference between the orbits, which at perhelion will be due to kinetic energy alone. This will allow you to get the change in orbital velocity needed.

- #3

SpaceTiger

Staff Emeritus

Science Advisor

Gold Member

- 2,940

- 2

In real life, you would need phase information -- that is, you'd need to know the positions of Mars and the satellite at a particular time. The fact that the orbit has aphelion at Mars' orbit doesn't mean you'll encounter it in any reasonable amount of time. In fact, if your satellite's orbit was resonant with that of Mars, you'd likely never encounter it at all!skiboka33 said:Seems like it's not enough information to solve the problems.

You almost certainly don't need to worry about these things, however. The problem should be solvable using the information given, along with the procedure Janus described.

- #4

- 181

- 0

Last week of school, already started studying for finals, an astronomy assignment isn't exactly on my radar. Went to school this morning, oh **** I forgot to do this assignment. And this one was actually tough! Flipped it off in an hour and a half. 60% at most. Oh well. I pwn that class anyway.

Sorry this isn't a more helpful post, although the thing was due five hours ago so I guess help now wouldn't help you too much.

- #5

- 3,598

- 1,434

True, and in addition, in real life you would need to know at what position Mars will be in it's orbit in relation to its perhelion when intercept is met. Mars' orbit is eccentric enough that if you based your [itex]\Delta V[/itex] on its average distance from the Sun you could find yourself missing Mars by some 21 million km.SpaceTiger said:In real life, you would need phase information -- that is, you'd need to know the positions of Mars and the satellite at a particular time. The fact that the orbit has aphelion at Mars' orbit doesn't mean you'll encounter it in any reasonable amount of time. In fact, if your satellite's orbit was resonant with that of Mars, you'd likely never encounter it at all!

As a result, when you launch a probe from Earth, it takes the least [itex]\Delta V[/itex] to intercept Mars when you launch in the last half of February and the most if you launch in August. (this is just for intercept and doesn't take account the [itex]\Delta V[/itex] needed to match orbit with Mars once you get there.)

This leaves a few best launch "windows" where both the energy needed is the least and Mars and Earth are in the proper relative positons of their orbits for intercept.

But again, for this question, you are allowed to simplify and assume that Mars is in a circular orbit.

- #6

- 5

- 0

- Last Post

- Replies
- 6

- Views
- 5K

- Replies
- 3

- Views
- 2K

- Replies
- 6

- Views
- 3K

- Replies
- 9

- Views
- 966

- Replies
- 6

- Views
- 5K

- Replies
- 1

- Views
- 2K

- Replies
- 21

- Views
- 11K

- Replies
- 1

- Views
- 2K

- Last Post

- Replies
- 4

- Views
- 3K

- Last Post

- Replies
- 7

- Views
- 3K