Basics of Space Flight

Editorial Page


NASA logo This document was first prepared in 1993 by Dave Doody and George Stephan of JPL's Mission Operations Section (391 as it was named back then) in association with the Section's Training Working Group. The 21st Century Edition was written by Dave Doody with Diane Fisher's editorial and technical expertise. Minor updates continue to be published every few months, or more frequently if readers report needed corrections.

If you have a question about any of the content in this document, you may send email to Dave Doody (use the above link). Dave is currently the Realtime Flight Operations Lead engineer for the Cassini/Huygens Mission.

What is JPL? The Jet Propulsion Laboratory is a Federally Funded Research and Development facility operated for NASA, the U.S. National Aeronautics and Space Administration, by Caltech, the California Institute of Technology. Here's a downloadable PDF-format brochure, called JPL-101, that describes JPL from a historical perspective.

Latest Updates

The July 27, 2015 edition includes an improved chapter on Navigation (Chapter 13), thanks to contributions and edits by Jonathon Smith, and a reference trajectory image and animation by Brent Buffington.

The Banner Images:

The banner at the top of this page is the same banner used on the site's front page, as well as the Guide, Index, Glossary, Units of Measure, Links, and Completion pages.

On this banner's left side is a photograph of the Delta-II vehicle launching the Stardust spacecraft on February 7, 1999, at 4:04:15 p.m. EST, from Cape Canaveral Air Station, Florida. The full movie from which the frame was taken is available here. (The movie contains some remarkable footage taken from aboard the launch vehicle.) The image in this banner captures the separation of solid-rocket boosters, which are seen falling away. The remainder of the banner image is cut from an image of the Flame Nebula star-forming region in Orion, from the 2MASS showcase (2 micron all-sky survey), University of Massachusetts and Caltech IPAC, Infrared Processing and Analysis Center. The image's color balance was shifted for the banner.

The banner appearing on the Section-I pages features the Sun in a SOHO EIT (Extreme ultraviolet Imaging Telescope) 304-Angstrom image. The Sun was chosen to illustrate this section because its mass, gravitation, radiation, and magnetic field dominate the environment of interplanetary space.

The Section-II banner is a section clipped, rotated, and edited, from this image taken in the Kennedy Space Center, Florida, Spacecraft Assembly Facility. The people in the image are installing the Remote Sensing Pallet (optical instruments) onto the Cassini Spacecraft not long before its launch in October 1997. Additional images from pre-launch assembly can be found here.

The Section-III banner shows the late Robert Springfield, a Cassini Mission Controller on console in the Cassini Mission Support and Services Office Flight Operations area at JPL. More on Cassini Flight Operations here.

The 21st Century Edition (February 2001)

Much of the text from the original 1993 Basics of Space Flight online version was retained during the major re-write in February 2001. It was augmented and edited to improve clarity and simplicity, with the intention of keeping focused on "what's the point here?" Additional material was added to reflect the current and planned sets of interplanetary missions, as well as some Earth-orbiting missions. The graphics were updated and reworked to enhance clarity, and some animated .gif files were added.

The world-wide-web was in its infancy when Diane Fisher first took the initiative to put The Basics of Space Flight out there. Today the web is well populated with resources, to say the least. Just about everyone, from people who create scientific instruments flying on spacecraft, to launch vehicle manufacturers, have their own website. This edition is highly connected, to take advantage of some very good external sites. Good links, and the document's animated diagrams, make it much more informative as a web document than it was in paper. Oh, and speaking of links...

Link Disclaimer: Throughout this site there are links to various other websites whose content we do not control, and for which we cannot be responsible. Nor does any link serve as an endorsement of any kind. We provide links, and try to maintain them, as a convenience only.

Broken Links?

Of course, all those links pose a problem: they are subject to breakage. We've tried to select links less likely to break, but break they will. Please let us know when you find a broken link (email Dave). Your input will be much appreciated. Other minor corrections, changes and additions will be made to the document on an irregular basis.

Efforts have been made to retain hyperlink anchor name points from the original 1993 online version to avoid breaking links from external websites, however it may not have been possible to avoid breaking some. One drawback to having preserved incoming links is that there is now a wide variation among the lengths of pages, and in the number of pages per chapter.

Treating "Data" as if it were a Singular Noun

We do realize the Latin "data" is really the plural of "datum," one single point of data. In this document, though, we're going to boldly waive the laws of grammar for this word only, and treat "data" as if it were singular. Just as with "sugar," there are lots of little bits. This approach releases us from having to wield awkward sentences to treat it as plural. In this document, data is a substance. It flows through pipelines and processors.


The 2013 update was accomplished by Jonathan Castello.

John Bercovitz of the Lawrence Berkeley National Laboratory kindly located many needed corrections on his own accord, and these were worked into the 2004 uodates. Thanks to Dr. Robert B. Giffen (BGen, USAF, retired), Professor Emeritus, USAF Academy and Chief Operating Officer of Teaching Science and Technology, Inc. for information about his book, Understanding Space, An Introduction to Astronautics, and for interest in referring students to Basics of Space Flight. A link to the book appears on the Links page. Thanks to Cassini Ace John Ibañez for troubleshooting script problems that appeared in 2004.

The major re-write "21st Century Edition" was undertaken starting in 2000 by Dave Doody and Diane Fisher, working under the auspices of the JPL Mission Execution & Automation Section (368). Diane created most of the animated images, and performed technical editing of the entire document.

Thanks to Susan Watanabe and Mary Beth Murrill of Media Relations for their reviews and advice pertaining to the 21st Century Edition. Thanks also to Susan Kurtik for funding, to Ben Toyoshima for guidance, to Gerardo Rivera and Robert Antonio for the quiz scoring engine, and to Eric Tauer for web technical advice and for delivering the nice animation handling script in a timely manner. Thanks to Bill Kurth for help with information about the heliosphere, to Jeremy Jones for reviewing navigation issues, and to Troy Goodson and Duane Roth for their illuminating input on navigation. Thanks to Steve Edberg for help with things astronomical, Laura Sakamoto, Steve Slobin, and Robert Sniffin for expertise with telecommunications and DSN topics, to Betsy Wilson for lots of help with the telemetry section, and to Trina Ray for enthusiastically reviewing Radio Science and DSN stuff. Thanks to Greg Chin, manager of the Cassini Mission Support & Services Office, who granted the author freedom to work on this edition during a busy Jupiter flyby period for the Cassini Mission to Saturn, and to continue keeping it current as the Cassini Saturn Tour progresses.

For the original 1993 version, Diane Fisher provided technical editing and illustration, and took the initiative to publish it on the fledgling world-wide web. Cozette Parker assisted with the initial hardcopy publication. Brad Compton kindly tolerated the author's preoccupation with this project during Magellan's demanding mission at Venus. Special thanks to the original reviewers Ben Toyoshima, Larry Palkovic, Carol Scott, Rob Smith, Dan Lyons, and Bob Molloy, and to field testers Kathy Golden, Steve Annan, Linda Lee, and Paul Porter for their valuable comments. Thanks to Roy Bishop (Physics Department, Acadia University, and the Royal Astronomical Society of Canada) for his independent review.

Image Credits

Clicking on an image in the document will bring up a page citing credits if any are appropriate. Some images link directly to a related website.

Honors and Kudos Received

Here's a list of awards and commendations received, along with the story about how the Basics of Space Flight document got started, and how it became popular.

From 1995 through 1997, The Planetary Society published Dave Doody's regular column, "Basics of Space Flight" which drew and embellished on the original version of this document. Some of those articles still appear in the "publications" section on The Planetary Society's website. Aspects of this material were incorporated in the 21st Century Edition.

PDF Version

With the 21st Century Edition in February 2001, emphasis shifted to use the web as the primary medium for access to the Basics of Space Flight. Users will benefit most from the online web version with its occasional corrections and updates, and its extensive links and animations.

For those who would nonetheless like to download the entire tutorial to study at leisure without being connected to the internet, we have prepared a PDF (portable document format) file which can be viewed on your portable device or computer, or printed to paper. It was generated as a snapshot of this online Web site in February 2011. You can view or print it using the free Adobe Reader. It has color illustrations, and is not formatted for the Kindle. Some devices and PDF reader versions will allow the URLs in the Chapter Endnotes to operate. There are no other interactive features or animations. A hardcopy book is also available from

Click this icon to download the 20-MB Basics of Space Flight PDF.
Updated 2011 August 10.
Acrobat Reader

JPL document number, publication clearance numbers, title, and author, are as follows (release date is shown at the top of this page):

    JPL D-20120, CL-03-0371, CL-11-1594 (PDF), and CL-15-3027 for Chapter 13, which was the first of several chapter updates that are being given separate clearances for unlimited release.

    Basics of Space Flight
    Dave Doody

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1 The Solar System
2 Reference Systems
3 Gravity & Mechanics
4 Trajectories
5 Planetary Orbits
6 Electromagnetics

7 Mission Inception
8 Experiments
9 S/C Classification
10 Telecommunications
11 Onboard Systems
12 Science Instruments
13 Navigation

14 Launch
15 Cruise
16 Encounter
17 Extended Operations
18 Deep Space Network