# Presentation: 247775

## Dave Doody
CASSINI REALTIME OPERATIONS

- CASSINI REALTIME OPERATIONS

**Basics of Interplanetary Flight**

## Basics of Interplanetary Flight

**Basics of Interplanetary Flight**

- An Introduction to the **online** tutorial:
- _[http://www.jpl.nasa.gov/basics](http://www.jpl.nasa.gov/basics)_
- ...which is a survey broad in scope, but limited in depth.
- The online tutorial’s goal is to describe the main concepts that apply to interplanetary space exploration, and how the relationships among them work.

## Today’s session

- The interplanetary environment
- Some spacecraft and their results

- With ongoing Q & A  - don’t hesitate to interrupt!

## A

- _[http://ipac.jpl.nasa.gov/web_movies/pa/ssc2004-22v2_full.mov](http://ipac.jpl.nasa.gov/web_movies/pa/ssc2004-22v2_full.mov)_

- Cartoon of a young star with protoplanetary disk
- Movie available if you want to see it rotating and evolving:

**A**

**B**

**C**

**D**

## Here’s a real protoplanetary disk

- HH-30 in Taurus, about 450 light years away.

## The results:

- A central star containing 99.85% the cloud’s mass

- Gravitation that rules everything in the area

## The results:

- A central star containing 99.85% the cloud’s mass

- Gravitation that rules everything in the area

- Pre-existing, dominating motion

## The results:

- A central star containing 99.85% the cloud’s mass

- Gravitation that rules everything in the area

- Pre-existing, dominating motion

- Radiation: heat, light, UV...

## The results:

- A central star containing 99.85% the cloud’s mass

- Gravitation that rules everything in the area

- Pre-existing, dominating motion

- Radiation: heat, light, UV...

- Extensive magnetic field
- The solar wind and coronal mass ejections

## http://sohowww.nascom.nasa.gov/hotshots

- _[http://sohowww.nascom.nasa.gov/gallery/Movies/C3_Apr01/C3_Apr01sm.mpg](http://sohowww.nascom.nasa.gov/gallery/Movies/C3_Apr01/C3_Apr01sm.mpg)_

- This movie, from the SOHO spacecraft’s LASCO instrument, blocks out the Sun’s central glare to reveal the unrelenting stream of material in the corona: solar wind and coronal mass ejections. Note the background stars moving left to right.

## Earth’s magnetic field shields us

## Why are we looking at Ed Stone’s kitchen sink?

- View the animation at    http://www.jpl.nasa.gov/basics/bsf1-1.html

## Orbits

**Orbits**

## Apoapsis

- Mt.

## Apoapsis

- Periapsis

## Apoapsis

- Periapsis

- So, you added energy up here at...

- And the effect was to increase altitude at...

- ...until the cannonball didn’t hit the ground.

## Apoapsis

- Periapsis

- The opposite is true, too: if you **add** energy at...

- You’ll increase the altitude of **Apoapsis**.

## Apoapsis

- Periapsis

## Periapsis

**PAY NO ATTENTION TO THE DIRECTION REVERSAL ON THIS PAGE**

- Apoapsis

## The Hohmann Transfer

- A Hohmann transfer is a fuel-efficient way to transfer from one circular orbit to another that is in the same plane, but at a different distance from the central body. Named for Walter Hohmann, the German scientist who published it in 1925.

- Half an elliptic orbit touches both the orbit you wish to leave (*1*) and the orbit you wish to reach (*3*).The transfer (*2*) is initiated by firing the spacecraft's engine to accelerate it to follow the elliptical orbit.

- Consider a flight from Earth to Mars. At the beginning, the spacecraft will already have velocity associated with its Earth orbit ミ this velocity will not need to be found when the spacecraft enters the transfer orbit (around the Sun). At the other end, the spacecraft will have to decelerate and allow Mars' gravity to capture it.

## The Gravity Assist Mechanical Simulator

## The Gravity Assist Mechanical Simulator

- View movie at    http://people.artcenter.edu/doody/gams

- Jane Houston Jones demonstrates a gravity assist to Saturn by stealing momentum from Jupiter. Thanks, Jane!

## Oh, and one more result...

## Oh, and one more result...

***Planets!***

***And stuff***

## Slide 25

## http://www.jpl.nasa.gov/basics/saturn

- http://www.jpl.nasa.gov/basics/saturn

- A large image of Saturn in “normal” backscattered light is also annotated on the web page.

- Annotated natural color image as Cassini observed Saturn from within its shadow, 15 September 2006

## http://www.jpl.nasa.gov/basics/saturn

## Science Instruments

-  19  -  cm aperture telescope
- (7 3/4  -  inch)
-  f/10.5 Cassegrain
-  1  -  megapixel CCD (.35° FOV)

**Cassini’s Narrow Angle Camera    (for closeups)**

## Science Instruments

**Cassini’s ****Wide Angle**** Camera**

-  5.7  -  cm aperture telescope
- (2 1/4  -  inch)
-  f/3.5 refractor
-  1  -  megapixel CCD (3.5° FOV)

## Science Instruments

**CCDs: Charge Coupled Device imaging sensors**

## Science Instruments

**And other components of the Cassini Spacecraft**

- http://www.jpl.nasa.gov/basics/cassini

## Sending image data back to Earth

## Deep Space Network - DSN

## Download & build your own DSN Station!

- http://www.jpl.nasa.gov/scalemodels

## dave.doody@jpl.nasa.gov

**for participating!**

**Thanks**