Orbiter 2014 (Beta)

While I'm still quite interested in all sorts of "space stuff," it's been a very long time since I did anything with the Orbiter space flight simulator. When I first discovered Orbiter in 2005, I was pretty excited. I was always interested in space, in flight simulators, and in physics, and Orbiter combined all those interests into one very cool piece of (free!) software. As part of the process of teaching myself how to use Orbiter, I wrote a tutorial manual called Go Play In Space, and I did a substantial update for the 2006 version of Orbiter. In late 2010, I started to work on an update for the 2010 version, but I got sidetracked by other interests and priorities, and never finished that project.

Last week I noticed a YouTube video by David Courtney called called "Orbiter 2014 Beta - A Quick Look" (David has recorded a large number of excellent tutorial videos on Orbiter 2010).  Wow, it's alive! Orbiter creator Martin Schweiger has released an early beta of a new version that includes 3D terrain (with high-res data so far for most of Earth as well as Mars and the Moon), along with various improvements in the physics engine and user interface. I read some of the discussions at the Orbiter Forum and decided to at least check it out.

The terrain for the new version must be downloaded and installed separately from the Orbiter beta itself (there are instructions and also a beta installation video by David Courtney). I installed the high-res terrain tiles for the US west coast, since I'm familiar with the Los Angeles area, which has some interesting mountain and valley terrain. I flew the default Deltaglider around for a while, and the general impression is similar to Microsoft Flight Simulator, though it's not quite as detailed.

You might question why 3D terrain is even necessary in a space flight simulator, since most of the time you are too far from any planet's surface for this to make any difference. I guess it comes down to realism, and "because you can." I have spent a lot of time with the wonderful AMSO add-on for Orbiter, simulating Apollo missions in great detail, and it is certainly cool to land in the great lunar terrain that is supplied with that add-on (check out this AMSO Apollo 17 video, complete with real mission audio - skip to 9:00 or so to see the mountainous terrain up close).

I'm happy to see Orbiter development continuing, and I hope to do something with the 2014 version. Updating Go Play In Space is a lot of work (it's a 181 page book), but it really needs a 2010-2014 update, so maybe that will happen, time and energy permitting!

More iPod Shuttle (Landing Tips)

I'm still obsessed with F-SIM Space Shuttle on the iPod Touch. Now that I'm a seasoned pro with some 10 hours (!) of flight time and at least one "good" landing (with 26 "safe" landings, 54 "hard" landings, and an embarrassing number of crash landings), here are a few things I've learned along the way. While it may seem odd that someone with such a poor record and slow learning curve has the audacity to offer landing tips to others, here's the thing: I've made these mistakes enough times to notice what they are, and if you can avoid some of them as a result, you'll be ahead of the game. This only applies to "final approach" landings. I've done a few full HAC approaches, but I still really suck at those, so too soon to give tips.

1. Read the "help" landing tutorial and watch a few Autoland demos, paying careful attention to the flight path marker (FPM) and approach cues in the HUD (the tutorial explains these with pictures). After you've landed a few times, also read the landing notes in part 2 of the help - good tips, but you'll need some experience to recognize them.
2. If you don't let the FPM get far from where it should be (and you shouldn't), the range of tilt and rotation motions you need is very small. The iPod Touch is so light, it's very easy to make motions you don't want that can really throw off your approach. I find I have to brace my elbows against my body and cradle the iPod carefully to keep it steady and in balance. And have my eyes very close to the screen.
3. Make very small adjustments, and don't ever let the FPM get far from the guidance diamond or the flare cues (small triangles).
4. Get lined up with the runway center line right away, and keep it lined up. I always try to do this but still sometimes end up off-center when I'm below 500 feet (maybe cross wind?). Sometimes I can correct this, but it's bad to have to try and I often fail. You don't see the real shuttle banking around on short final - you should be wings-level once you are below 1000 feet.
5. The FPM shows where the shuttle is heading. If you let it get above the horizon when you flare, you will gain altitude and will probably have trouble with line-up (a slow shuttle doesn't have great control authority) or a soft enough landing.
6. You seem to get more "good landing" credit for landing in the 200' touchdown zone than for being on-centerline. My one "good landing" was in the zone but somewhat off-center for 187,000 points. My best "safe" landing was 370,000 points and was well centered, but outside the landing zone.
7. If you use "tilt" for brakes (rather than manual brakes which is an option), once the nose wheel touches down, tilting forward provides more braking. But don't do it right away lest you slam the nose wheel down too hard.

The picture above is an animated GIF (might have to click on it) of an Autoland demo at KSC at night, passing through clouds (not real time - just captured frames at 0.8 sec intervals). I love that effect, when the KSC ground lights pop out as you pass through the cloud deck (very quickly and steeply, 20 degree approach, remember) . This is a great little sim. Reminds of the old days (~2000) when I used to land a simulated F/A-18 Super Hornet on a carrier at night in Jane's F/A-18 flight sim. I wasn't very good at that either, but it was also fun. I'm glad I was better at landing real Cessna 152's (when I was flying a few years ago) than I've been at landing simulated Hornets and space shuttles. Guess it helps to have your life on the line! And to be approaching at 67 knots rather than 150 to 300 knots.

Not Just for Girls

I noticed The Girls' Guide to Rocking in the gift shop at the Experience Music Project in Seattle when I was out there recently (great museum, BTW). I wasn't sure if it was serious or not, so I waited to check it out on the web before buying it "for my daughter" (wink, wink).

Turns out it's a fun book, but also quite serious, and despite the title, not just for girls. Author Jessica Hopper covers pretty much all the bases for anyone who might be thinking of picking up an instrument, writing and recording some songs, or forming a band. Topics range from how to select a guitar or drum set to how to deal with conflicts in a band, how to record demos at home, how to promote gigs, and much more. Other topics include musical instruction, lyric writing, producers, managers, touring, stage fright, and the importance of ear protection when you're exposed to amplified music. It's a great book - Hopper covers a lot of useful and practical ground in 224 pages. Most of the quotes in the book are from female musicians (not all of them "rockers"), and there is a lot of encouragement aimed at girls, but this book would be really helpful for anyone trying to get started doing music (other than classical, I suppose).

I wish I had something like this when I was trying to be serious about doing music back in my college days (I was pretty clueless). And I actually do plan to give it to my daughter now that I've read it.

Human Japanese!

"Human Japanese" is sort of a funny name (as opposed to "dog Japanese?"), but it's a great piece of software if you are interested in learning or reviewing the basics of Japanese. Back in the early 90's when I was actively learning Japanese and also playing around with HyperCard on the Mac, I tried to develop some interactive Japanese lessons for vocabulary and for learning to read and write hiragana and katakana. I didn't get very far - it's a lot of work for one person and there wasn't much system support for this sort of thing in HyperCard.

But "Human Japanese" (version 2.0) is just the sort of thing I had in mind - self-paced, interactive, friendly, and easy to use, and best of all, it now runs on the iPod Touch (and iPhone) with its amazing touch-screen interface and audio capabilities (used for ~1800 native Japanese speech samples). The program covers basic grammar and vocabulary as well as reading and writing the two phonetic syllabaries, hiragana and katakana.

I played with the free "lite" version for about 10 minutes before deciding to spend $10 on the full version, which is an amazing price for any introductory Japanese text book, let alone an interactive one with embedded audio and animations. Learning Japanese is an interesting and complex task, and I still have a lot of interest in Japanese learning methods and materials, as well as an affection for the language. I would like to retain some level of skill even though I rarely go to Japan these days (my most frequent Japanese task is checking business card translation proofs for colleagues at work who are traveling to Japan).

Based on the quizes I have tried in several chapters, I still know this basic material pretty well, but anything that gives me a reason to play with Japanese is cool, and I really like this app a lot. It's 30 MB with 40 chapters, with many exercises and quizzes, audio for all Japanese text, and a lot of explanatory English text that is actually fun to read. It quickly transitions you to reading and writing Japanese in the Japanese phonetic system rather than in "Roman letters" which is a really useful thing (for further study as well as for reading many signs and menus in Japan).

If you have an interest in Japanese study at any level, I think you would like this learning software. You could learn basic vocabulary and grammar as well how to read and write kana very quickly and easily, and it would also be good for reviewing the basics if you're a bit rusty. It's available now for Windows XP or Vista in addition to the iPhone/iPod Touch version. A browser-based version is planned for Mac/Linux users.

Europa-Callisto Joyride

In preparation for my April 14 IYA podcast, I wanted to add some graphics to my Flickr site to further illustrate the simulated Europa to Callisto journey that I "dramatize" in the podcast. The basic tools for this are Orbiter, IMFD v4.2 (not the latest version), and Andy McSorley's excellent Europa to Callisto IMFD tutorial. These are all free downloads.

IMFD is an amazing interplanetary navigation tool by Jarmo Nikkanen. Andy's tutorial was inspired in part by an earlier IMFD tutorial by Robert Denny, which also exists in video form. I prefer Andy's tutorial because it explains more about the various specialized terminology used in IMFD. I've been away from IMFD for a long time, so I had to read through Andy's tutorial completely before successfully flying from Europa to Callisto yesterday morning. This is also an excellent illustration of the "forgetting curve" since I was the proofreader and tester for that tutorial while Andy was developing it. Of course that was a couple of years ago and I can barely remember what happened last week (I think I was in Europe, not Europa).

It was not completely successful trip (I mean the Callisto one - the Europe trip went rather well). Rather than starting with Andy's tutorial starting point scenario, I took a different starting scenario and changed the date to March 14, 2084. This gave me some nice views of Io but it was not the best starting date for a time- and fuel-efficient transfer. Fortunately the Delta Glider carries a lot of fuel for its nuclear fusion (or whatever) rocket engines. The other thing was that I missed a step and ended up with a retrograde orbit (orbiting opposite the direction of rotation of Callisto, orbital inclination of 163.76 degrees in my case). This doesn't matter much when you're on a simulated joyride but IMFD allows you to precisely determine your arriving orbit if you use it properly, and I just sort of said "whatever." The picture above shows the final Callisto orbit.

Stargazers to Starships

I rediscovered a great astronomy and spaceflight educational site I had bookmarked a while ago. "Stargazers to Starships" is the work of David P. Stern, and although its web design is simple (no Flash or Javascript here), the content is great. It's logically organized and the explanations are clear and well written. Most pages also have "questions from users" section at the end (with links to answers), which is a wonderful feature. Dr. Stern also provides lesson plans based on his site, with problems for students as well as suggested questions for discussion.

The main sections are "Astronomy of Earth's Motion in Space" (including a recently added section on the solar system), "Newtonian Mechanics" (with a great optional section on spaceflight to Mars), "The Sun and Related Physics," and "Spaceflight and Spacecraft." There's even a math refresher section and a timeline.

This is a great resource for teachers or informal educators as well as for student projects.

Europa Visitor

I've been getting over an illness and haven't had much energy the last week or so, but over the last few nights, I did manage finish my 365 Days of Astronomy podcast for April 14, "Exploring Space with Your Computer" (it's due by March 14, but because of upcoming travel and other issues, I needed to get it done early). I really like how it came out. I wrote six short pieces of instrumental background music to set the mood for the different "scenes" in the podcast, and I used SONAR to record and mix the narration, special effects, and music into a small "radio play." It's almost 8 minutes long.

About half of the podcast involves Orbiter, and the opening scene (orbiting Europa) has gotten me interested in reviewing my space navigation skills, which are quite rusty. Not that anyone would know this from the podcast, but it bugs me when I can't manage a simple task like transferring from an orbit around Europa to Callisto using IMFD. The Jupiter system is great for navigation practice, by the way - it's like a mini-solar system, but instead of 6+ months to transfer from Earth orbit to Mars orbit, you can take maybe 4 days to transfer from a Europa orbit to a Callisto orbit. Of course time acceleration is used in both cases, but for Europa-to-Callisto, you can get there in a reasonable amount of real time without using extreme time acceleration that can sometimes cause problems.

Why Europa to Callisto? One reason is that there are several tutorials available for the IMFD (Interplanetary Multi-Function Display) "navigation computer" add-on. These include a couple of written tutorials for the older (but still very capable) IMFD 4 series as well as a cool video tutorial by Robert Denny for the more recent and advanced IMFD 5. That's what I'm reviewing first.

I Love ISS Too

There's a nice post today over at Universe Today, I Heart the ISS: Ten Reasons to Love the International Space Station, written by Nancy Atkinson. While it gets little respect or attention from the public at large, the ISS is one of the most incredible engineering projects in history and an impressive demonstration of international cooperation. And that's just two reasons to love it (my Orbiter shot is from STS-120 and doesn't include the new European Columbus module that was successfully installed this week).

Thanks to Orbiter, I have virtually flown to and docked with the ISS many times. Even in the simulation it's exciting to see it grow from a small dot to a giant satellite as you rendezvous and dock in your space shuttle (or in some futuristic space vehicle). If you have Orbiter (it's free), you can watch a flight recorder replay of rendezvous (called "sync" in Orbiter) and docking using the standard "Deltaglider" (DG) spacecraft rather than the shuttle. The DG's docking port is in the nose rather than on top as in the shuttle, which makes docking a little easier to master. The annotated replay is in the Tutorials folder and is called "DG-ISS Sync Dock." I recorded and annotated this replay to include with the 2006 release of Orbiter. There are detailed instructions to go with this tutorial replay in chapter 5 ("Dancing in the Dark") of my ebook Go Play In Space if you want to learn what's involved in getting to the ISS. You can also learn about Orbiter docking in videos, here and here (this shows how to dock the shuttle with the 1999 version of the ISS - it's grown a lot since then).

If you prefer your ISS information in traditional book form, I highly recommend the 2004 edition of Marianne Dyson's book Space Station Science. Like Orbiter and the ISS itself, it's not just for kids.

Interplanetary Trajectories

The MESSENGER spacecraft is closing fast on its close encounter with Mercury tomorrow (the Planetary Society has a detailed preview here, flyby simulation video here). This will be the first close approach to Mercury since Mariner 10 in 1974-75, and it will be very close - only about 200 kilometers from the surface! This is the first of three flyby encounters in 2008-2009, designed both for imaging/science and for trajectory modifications that will help MESSENGER to match Mercury's orbit and allow Mercury orbit insertion in March 2011. The 2008 passes should finally give us imagery of Mercury's entire surface (Mariner 10 was only able to photograph about half of the planet on its three flyby encounters). The planned one-year orbital phase will allow much more detailed study of this relatively unknown planet.

Launched in August 2004, MESSENGER's journey to Mercury has taken a rather indirect path, looking something like a pinball in a pinball machine in in the animated GIF above (linked from the Planetary Society web site). MESSENGER got trajectory help from several gravitational-assistance passes (Earth flyby in 2005, two Venus flyby's in 2006 and 2007, and the upcoming Mercury passes in 2008 and 2009 - here's a great diagram of the stages of the trajectory). Since Mercury is close to the sun, you might wonder why all this bouncing around is necessary, since it's pretty much "downhill" from Earth to sun-hugging Mercury, gravitationally speaking. While I don't know the specific constraints on the MESSENGER trajectory design, there are always complex trade-offs among payload (the mass available for instruments and spacecraft structures), propellant mass and usage, and timing. If you can wait longer to get there and use gravitational assistance from planets, you can carry a larger payload while needing less propellant to arrive precisely at your target at the right time and with the right velocity to do what you need to do.

This whole orbital mechanics business has interested me since high school. Aside from library books, I'm sure that the many "NASA Facts" and other documents that I got by writing to NASA played a big part. That was the Apollo era, so I was reading about free-return trajectories and orbital rendezvous and the like at a young age. At one point I thought that this might even be my career, since I was so interested in space and computers, but I took a path not unlike MESSENGER (with a music-assisted change in direction and university) and ended up in optics software instead.

Nowadays at places like JPL, interplanetary trajectory design is incredibly sophisticated. Simulation, optimization, and visualization software make it possible to meet all sorts of constraints and requirements and to perform and pre-visualize all sorts of "what ifs." If you would like to play around with this sort of stuff yourself, there is the great combination of Orbiter and IMFD (Interplanetary MFD by Jarmo Nikkanen, a wonderful planning tool that runs inside Orbiter itself, now up to version 5.1d). Gravity Simulator 2.0 is another great and free tool for playing with orbits and trajectories. You can even use JPL Horizons data to get real spacecraft data to use in your own simulations (see my earlier tutorial post on this).

Speaking of tutorials, I just found one for IMFD 5.0 that I had not seen before. It's a 20 minute narrated video tutorial by Robert Denny, and it's really cool (he has done earlier text/picture tutorials on IMFD which are still available, though they are based on an earlier version of IMFD). While this "simple tutorial" is very well done and clear, you should note a few points. One is that he assumes some basic familiarity with Orbiter and with orbital mechanics terminology. Another is that he is only showing the "MFD" instrument windows, not the full Orbiter screen. Orbiter has cockpit views, external views, and full 3D graphics, but for this tutorial, you are essentially "flying on instruments" and don't need to see that other stuff, though you would see the outside view if you were running this in Orbiter. Third is that Denny has chosen to transfer from Europa to Callisto, two moons of Jupiter. Jupiter is like a mini (but still huge!) solar system, so it's quicker and simpler in some ways to learn to do orbital transfers between moons there than between widely separated planets orbiting the sun. The same methods would apply to flying from (say) Earth orbit to Mars orbit. Even if you don't understand everything, you can see from this tutorial what a powerful tool IMFD can be, and it goes much farther than what is shown here. There are other (non-video) IMFD tutorials on Jarmo's site.

Getting Started with Orbiter

I was discussing Orbiter with a couple of people at a Thanksgiving gathering last night, and I realized I hadn't written anything about Orbiter for a while. Maybe it's time to begin at the beginning and offer some advice on getting started with Orbiter. In case you stumbled in on a random Google search or something, Orbiter is a free space flight simulator for Windows PC's. In Orbiter, you're a virtual astronaut operating various spacecraft under physically realistic space and atmospheric conditions - all simulated, of course. Although it's a simulation rather than a game, it's really fun (though challenging) to learn to achieve orbit, dock with space station, and land on the Moon, among the many missions you can fly.

How to get started? This assumes you have a Windows-based PC. Orbiter supports optional joystick controls, but most things can be done just as well with your keyboard and numeric keypad (which controls your thrusters and rocket engines).

1. Download Orbiter from one of the listed sites. The main zip file is pretty big, and there are some options like higher resolution textures (better looking planets and moons) in separate files, all explained here.

2. Use an unzipping program to extract the files and "install" Orbiter into a directory somewhere on your hard drive. There really isn't an installation procedure like most Windows programs, but when you unzip, you must make sure that "use folders" or similar is checked so the many Orbiter files will go into the correct directories or folders.

3. Run Orbiter (orbiter.exe in the installation folder) and look at the Video tab of the "Orbiter Launchpad" window. Set the screen resolution to match your PC's display, or to run in a window smaller than your full screen if you prefer (bigger is better).

4. Choose and run a scenario from the Scenario tab - a good one to try first is "Smack! Rescue" in the Tutorials folder. This is actually a flight recorder playback with on-screen notes, so you can just watch to get an idea of what Orbiter is like (there's no sound yet, that's normal). Use the right mouse button to spin the view around if you like. Press F4 to display the main menu.

5. If Orbiter seems to run OK on this test, exit or quit (click Exit on the menu, or Control-Q).

6. Download Orbiter Sound 3.5 from here and install it. This will add sound and music support to Orbiter - an essential free add-on (everything for Orbiter is free). Make sure Orbiter Sound is in the Active Modules list on the Modules tab of Orbiter Launchpad.

7. Download my free e-book (PDF) Go Play In Space and print out chapters 1, 2, and 3. These will take you through some background information and basic spacecraft operations.

8. Try other scenarios and just explore whatever interests you. Don't worry if some things seem pretty hard at first - there's a lot to learn, but you can do it if you have the interest.

You can also visit Orbit Hangar to look over some of the many available free add-ons for Orbiter, but it's best to start with the standard Deltaglider spacecraft and practice scenarios and tutorial playbacks until you get a feel for the basic operations. The Orbiter Forum is also a good place to visit to learn and to ask questions, but it's best to spend some time with Orbiter and Go Play In Space before you start to ask "how do I get to orbit?" in the forum. Hint: Fly east (90 degree heading), gain altitude to get above the thickest part of the atmosphere, and gain speed to achieve orbit. This is not easy at first, especially on Earth. It's easier to achieve orbit on the Moon or Mars so practice somewhere else first (this is the great thing about a simulator). Orbiter gives you lots of scenarios so you don't have to start at Cape Canaveral unless you want to!

Notes: There are two different versions of the space shuttle for Orbiter. The included one (Atlantis only) is great, but it has no built-in launch autopilot. The add-on shuttle fleet has more features including a launch autopilot, but it must be installed and is more complex to learn.

Note also that planet and moon surfaces in Orbiter are smooth textures, "painted on," and not 3D, though they look 3D from a distance. You can get 3D terrain for some areas of the Moon, Mars, and Earth as add-ons, but by default, surfaces are smooth and not too detailed when you are on or near the surface (except at the few surface bases that are provided, such as Cape Canaveral). This is because Orbiter is mainly a space flight simulator, not a ground or low-flight simulator.

Orbiter for Educators: Teaching is Hard!

Today I presented "Exploring Space with a Computer" at the Girls Scouts of Rhode Island SMART science/math event at Bryant University. This was the first time I had given this Orbiter-based talk in a situation with hands-on workshop possibilities, thanks to a well-equipped computer lab with 41 networked PC's. I installed Orbiter on 15 of them to support the estimated 10-15 middle-school girls per workshop (55 minute sessions, repeated four times). It was a good thing this installation was just a simple CD copy in Windows (I copied a complete home installation onto CDR for easy installation, but 3 or 4 copies instead of just two would have made the 15 installations go faster). The actual group sizes varied from 8 to 18, for a total of about 48 girls (plus adult leaders).

I kept the introductory PowerPoint and shuttle launch (playback) demo brief to allow most of the time to be hands-on with the software, and this worked pretty well. Most of the girls seemed to enjoy the activities, but I did learn some things that will help me improve such events in the future. For one thing, less is more. I had planned a solar system tour followed by a self-running planet/moon quiz using a different scenario. But it was clear that the time was better spent just exploring the first scenario, and making use of time acceleration, zooming, and panning to get a feel for the diverse appearance of the bodies of the solar system, as well as their motions. This was novel enough to hold their attention for about 15 minutes (the scenario had a lot of preset camera positions to make it easier to get around).

Another thing I should have done was make hand-outs that included step-by-step instructions for the Moon-base hover/rotate/move exercise. I had brought a few handouts (the requested copies from the organizers were lost in the shuffle of some 300 Girl Scouts and 70 presenters), and they listed a few main keyboard shortcuts and the keypad thruster controls, but not a step-by-step checklist. Duh! Many girls were too distracted by Orbiter itself to really watch my demos and listen carefully to the few essential steps I presented, and some ended up hurtling through space instead of hovering 10 meters over pad 4 at Brighton Beach Moon Base.

Two exercises (solar system tour and Moon Base Hop) were more than enough for 55 minutes, though I also had a space station docking exercise prepared! With step-by-step instructions, there might have been time for some free-form play and more questions and answers (I asked some but should have asked more, and the girls asked mostly "how do I fix this?!?"). I gave them handouts with download information to take home.

All in all a good first experiment with Orbiter in a workshop environment, but with setup from 7:45 to 10 am (plus a lot of preparation hours on Saturday afternoon and evening), and sessions from 10:30 to 3:30, I was really tired by the end of the day. I've taught many things, mostly professional training for adult engineers, plus some events for kids of various ages in optics and space. But I always forget how hard this is with kids, to stay patient and focused, and to keep it fresh. How do teachers do this day after day? Hats off to those of you who do!

Learning the Orbital Ropes

I write a lot about Orbiter, and a little bit about other software tools such as Gravity Simulator, and I've written Go Play In Space to help people get started with Orbiter (it includes quite a lot of background material too). But there's a lot of stuff that I more or less assume that people know if they're interested in space, and I have to admit that this is not always a good assumption. Fortunately we have the web, and I want to mention two sites that I have found really useful for understanding space flight and orbital mechanics.

JPL Basics of Space Flight - Quite complete, richly illustrated, essentially non-mathematical, and with brief quizes for each section to check your understanding. It's best used in the interactive mode though there is a PDF version as well.

Rocket & Space Technology by Robert A. Braeunig - Not as comprehensive but the explanations are clear and compact. There is a fair amount of high-school-algebra-level math. Also includes an excellent page clearly and simply debunking the "we never went" Moon-landing-hoax nonsense. Very nicely done.

Orbiter for Educators: Name That Moon

Next weekend I'm participating in a big educational outreach event for Girl Scouts in Rhode Island. It's called SMART (Science and Math Are Really Terrific), and I'm doing a space workshop. It's supposed to be hands-on, and it seems to be working out that I have a PC-equipped classroom so I can install multiple copies of Orbiter so the middle school girls can each have a go at playing in space (the event is at a university). Of course you never know with these things - I hope the PC's are up to the task of running Orbiter, and that I can really get the promised access to install it on them!

This means I need activities, and they have to be fun and something you can do without learning a lot about Orbiter (each workshop session is about 50 minutes). So I came up with three, a solar system tour and quiz (hoping to have some small prizes available), a "Moon hop" (hover and maneuver a Deltaglider from one pad to another at Brighton Beach on the Moon), and "final docking" with the ISS (starting from "hover" at 10 meters with slight misalignment to correct before docking). I've written brief cheat sheets for these things, and I'll also demonstrate.

For the quiz, I couldn't have them jump directly to the planets because they would then see the names directly. So I made a scenario with 13 spacecraft (Who_1 to Who_13) orbiting various bodies. You can press F3 to get the list of all the spacecraft, double click each one, and ID the planet or moon. Most are easy but there are a few tricks (like hiding a planet behind its moon at the start, requiring time acceleration to get around the moon to see the planet). I hope this is all somewhat fun and doable in 50 minutes - live testing next weekend.

Rocket Science for... um, Dummies?

The "for dummies" thing seems to be permanently with us, alas, though I supppose that's better than "for the complete idiot" (another popular book series). Rocket Science for Dummies isn't a book, it's a web tutorial on applied orbital mechanics using Orbiter. It's been around for a few years (since 2004) and is actually quite good - it's one of the things that helped me learn Orbiter back in 2005 and then inspired me to write my full-blown tutorial book, Go Play in Space.

The original version of Dummies was written by "Windlepoons" as a series of posts in a gaming forum. Last fall "Enjo" (Simon Ender) updated the tutorial for Orbiter 2006 and posted it in four parts on "Falcoleprof's" excellent orbiterschool.com educational support site. It includes some starting scenarios, good diagrams, and good explanations to help you get up and orbiting (and even docking in part 4) in almost no time.

Orbiter for Educators: Using JPL Horizons

JPL's Horizons system is a public-access database with current orbital data on many, many objects in the Solar System (both natural objects and spacecraft). Orbiter is a space flight simulator which includes a "scenario editor" that lets you interactively change the orbital data for any spacecraft in the scenario you are currently running. I was going to write an entry on how to use the web interface for Horizons to get information on (say) the Saturn-orbiting Cassini spacecraft and then transfer it to Orbiter using the Orbiter Scenario Editor. But before I could write this up, I found a better way, thanks to Tony Dunn, author of Gravity Simulator 2.0 (and also an Orbiter user).

First some general information. I won't attempt to explain Horizons itself - the FAQ and web access tutorial can do that. There are two basic types of data you can get, orbital ELEMENTS, and VECTORS (called "state vectors" in Orbiter), which we will use here. These are basically the (x,y,z) position and (Vx,Vy,Vz) velocity of the object relative to some reference body (e.g., Sun, Earth, Saturn, etc.), at a specific date and time. The date and time are encoded as a number called the "Julian Date" (JD), though Orbiter uses a modified version called (logically enough) "Modified Julian Date" (MJD). The idea is to get accurate information on an object of interest from Horizons, convert it if necessary, and enter it into Orbiter, so you can answer a question like "what does Saturn look like from Cassini right now?"

Conceptually this is quite easy (grab the date and vectors and pop them into the scenario editor), but there are a few things to learn, including the right questions to ask Horizons, and how to get the resulting data into Orbiter. Units, dates, coordinates, and reference bodies require a bit of explaining and possibly some conversions (m vs. km etc.). Nothing terrible, mind you, just a few details to keep straight.

Tony Dunn provides an easier way with his simple little utility program cfgData.exe (120 KB .exe file download) and the Horizons "batch" email interface. Download the program to any convenient directory (no installation needed) and run it. You can then enter the desired date/time and choose the object (e.g., Cassini Spacecraft, object -82 for JPL) and "center body" (e.g., Saturn barycenter, object 6 for JPL) from drop down lists of available JPL objects. Choose VECTORS, click [Create E-mail], and copy the resulting block of text to the clipboard with the button that appears. Go to your email program and create a new message. Paste the text into the body of a new email window, enter job as the subject, email to [email protected], and wait for the reply (usually very quick).

Select ALL the text of the reply and copy to the clipboard (check for error messages first - I just requested Cassini data for March 2009 and it's not available). Back in the cfgData window, click the [next > ] button (a new window appears), paste the return text into the new window, and click the [Create Data] button...

This is where it gets slightly tricky. The MJD and state vector data has to be copied and pasted into the right spot in an Orbiter scenario (.scn) file using a text editor like Notepad. It's easiest if you already have a scenario that is generally doing the right thing (like orbiting Saturn), so you only have to paste in the new MJD, RPOS, and RVEL data over the prior data, save it, then launch Orbiter and run your new scenario.

How do you get that starting scenario? If you've installed the Cassini add-on (shown above on 3-27-07) you will have a scenario (in the Grand Explorations folder) called Cassini Phoebe Flyby.scn which will have Cassini with STATUS Orbiting Saturn. Just copy the new date (MJD) and replace it in this file, copy the RPOS and RVEL lines in place of the old ones, Save As with a new name, and you're ready to run. Or take any Earth-orbiting scenario with a spacecraft (Deltaglider or whatever) with STATUS Orbiting Earth and change Earth to Saturn, paste MJD, RPOS, RVEL data, save, and run.

Note: You can also get orbital elements from Horizons for natural bodies such as asteroids and use this data in configuration files to add these objects to your Orbiter solar system. This has more steps, and you might consider using this utility to easily define minor planets in Orbiter.

Orbiter for Educators: View the Force, Luke!

Forces are fundamental in physics, and while you can feel some of them (like the force of gravity holding you in your seat), you usually can't see them. Except in Orbiter, which can display colorful vectors to show the forces that are acting on any spacecraft, updated in real time. It's pretty cool. Here's a quick way to demo this, using the flight recording of a launch of the space shuttle Atlantis. I assume you've installed Orbiter and know how to find and launch a scenario (if not, refer to the first post in this series or see Go Play In Space).

1. Start Orbiter, open the folder Playback, and double click the scenario Atlantis Launch.

2. Press [F4] to open the menu, then click Visual Helpers...

3. Click the Forces tab and check the box labeled Body force vectors. Also check the Total box so you can see the "resultant vector" (net result of all forces). Adjust the Scale and Opacity sliders as desired.

4. Press Control-I (info) to display information about the selected object (by default, the shuttle), including its mass and altitude.

As Atlantis launches and climbs to orbit, you'll see a big blue vector representing the thrust (T) , a yellow G vector (represents force of gravity, i.e., weight), a smaller red vector for drag (D), and a white "total force" vector (F). You may also see a smaller set of vectors representing the forces on the payload inside the shuttle's payload bay.

The force vectors are labeled with values in MN (mega-Newtons - 1 MN is about 225,000 pounds of force). Watch as these vectors change size and value as fuel is burned (reducing mass), the atmosphere gets thinner, and the shuttle changes orientation. Notice that thrust is greater than the sum of weight and drag, as it must be if the shuttle is to climb and accelerate. Note that drag increases for a while (due to increasing speed) and then falls off (due to thinner air at higher altitude). When the solid rocket boosters (SRB's) separate at about 2 minutes into the flight, they will have their own force vectors, and the thrust and weight values of the shuttle itself will decrease (no more SRB thrust, and mass is also reduced).

When the shuttle reaches about 153 km altitude, main engines will shut down and the external tank will separate (though the shuttle would really roll upright before separation from the ET). At this point, both the shuttle and the ET will be in orbit, and the only force visible will be "G" or weight. Is this correct? Isn't the shuttle "weightless" at this point? Not really. In orbit, the shuttle will be in free fall, pulled toward the center of the Earth by gravity but constantly "falling around" the curved Earth. With nothing to resist its motion and "push back" (like the chair that you feel pushing against you when you sit), the shuttle and its occupants will continue to fall freely and will not feel their weight. While it's often called "zero G," gravity is not zero when you are in orbit.

Orbiter for Educators: Solar System Tour

Continuing with the quick stuff you can do with Orbiter, here's how to take a quick tour of the Solar System. Although Orbiter scenarios generally include spacecraft and involve operating them (you can even switch between multiple spacecraft), you also have direct access to Orbiter's camera without bothering to fly anything. Regardless of what any spacecraft may be doing, you can use the Camera dialog box to move the camera to any planet or moon or to any surface base, spacecraft, or space station that is defined in the current scenario. Once there, you can control the field of view and zoom level of the camera, and move it around with the mouse.

Orbiter also gives you control over time - the Time Warp dialog can speed up or slow down time at will, from 0.1x (10% of real time, slow motion) to 100,000x. You can also selectively turn on various text labels so you can tell what planets, moons, stars, and surface features you are looking at. This is controlled by the Visual Helpers dialog. Here's a quick tour of the Solar System:

1. Start Orbiter and Launch a Scenario - See the January 10 post if you need advice on installing and starting Orbiter (remember to go to the Video tab to set your screen resolution before running a scenario). Although you can tour the Solar System in any scenario, the best one to use is Grand Tour which is found in the folder labeled The Solar System. This scenario has good pre-defined viewpoints for most of the planets and moons of the Solar System.

2. Open the Main Menu - Once you see the 3D view of Earth, press [F4] to display the main menu, then click Camera... to display the Camera dialog. You should also open up the Time Warp dialog so you can easily speed up time to see the rotations of the planets and moons. The Visual Helpers dialog lets you turn various labels on and off (helpful with Jupiter's moons when you are zoomed out and speeded up to see them zipping around the Jovial Giant). You can open these dialogs as needed or leave them open on the screen as Orbiter runs.

3. Tour the Planets - Play with Target and other buttons in the Camera dialog to see what they do, then click the Preset button. Double click any item in the list of presets to go to it. Try clicking the 1000x button on the Time Acceleration (Warp) panel to make the motions more apparent (you can also use the T key to speed up and R to slow down). Use the Visual Helpers dialog to turn on Planetarium mode and select various labels and grids.

That's it! You can zip around the whole Solar System in about 10 minutes, but be sure to take time to smell the roses (on Earth anyway). Use the mouse (right button) and mouse wheel to change the view and zoom. For more details and ideas for touring, see the second half of chapter 2 in Go Play In Space.

Orbiter for Educators: (Almost) No Prep

Orbiter is a freeware space flight simulator for the PC that I have written about extensively in this blog and elsewhere. Aside from being a fun way to "Go Play In Space" (the title of a free tutorial ebook I wrote about Orbiter) for people with an interest in space flight, Orbiter also can also be a useful tool for teaching about the solar system, space flight, atmospheric flight, physics, and other subjects. If you're a teacher, you might say, "Great, but when would I have time to learn this thing?" I don't know the answer to that, but the good news is that there are some cool things you can do with very little preparation beyond downloading and installing the software (~20 minutes on a good connection) and following a few instructions. These include giving a cool 3D tour of the Solar System and showing pre-recorded "flight recording" playbacks of the simulated launch and landing of the space shuttle (not just a video - you can control the "camera" and view it from inside or outside the cockpit).

This is not quite "no prep," but it's pretty easy. In later installments I will describe things you can do if you can take a little time to learn more about Orbiter. Here are the basics to get you started, which are described in more detail in Go Play In Space (this is a free 9 MB PDF download).

1. Download and install Orbiter - Go to and print the Download page of www.orbitersim.com, where you will find download and installation instructions and a list of "mirror sites" where you can get the actual files. Download the full Base package (63 MB) for Orbiter, and if possible, also download the high-resolution (L10) Earth textures (79 MB) and hi-res "Planets & Moons" (72 MB). These are not strictly necessary but they make the planets look even better (see chapter 1 of Go Play for more details).

2. Download and install Orbiter Sound - This is a separate but nearly essential "add-on" package that is easy to install and adds all sorts of sounds and even music to the otherwise silent Orbiter (sound is easily configurable). Go to Dansteph's download page, download, and run the file Orbiter Sound 3.0 (10.4 MB) to install it (see chapter 1 of Go Play for more details).

3. Start Orbiter and Choose a Playback Scenario - Double clicking the Orbiter icon displays the Launch Pad, where you can pick and run a scenario from one of many folders (go to the Video tab first to set your screen resolution). Double click the Tutorials folder and then the Atlantis Final Approach playback scenario (a very quick playback with on-screen text explanations). Once the playback starts, it will switch to different views automatically. When it first goes to an internal view, press [F8] to switch to the 3D "virtual cockpit" which looks more like the real shuttle cockpit. You can manually toggle between internal and external views with [F1].

4. Learn the Basic Operations - The main view things are that holding the right button and moving the mouse lets you move the camera around, while the mouse wheel (or PgUp/PgDn) controls camera zoom. The [F4] key displays the main menu. Choose Exit from the menu to quit (or use Control-Q).

5. Watch Atlantis Land - Orbiter is interactive - you can do everything yourself and even take over a playback at any time to fly it yourself - but playbacks are nice for talks because you only have to worry about the views. Another quick tutorial playback is Smack! Rescue (described in chapter 2 of Go Play), and Atlantis Launch, found in the Playback folder.

I'll do a "some prep" article soon to talk about touring the Solar System and taking control of an orbiting spacecraft. Later articles will talk about using add-ons to simulate historic space missions , making forces visible, and other subjects.

MiGMan in the Danger Zone

My friend Peter "MiGMan" Inglis is a multitalented guy. In addition to being a professional classical guitarist (his Whole Guitarist web site is great) and author (Guitar Playing and How It Works), he's a flight simulation expert. For years he's been channeling his knowledge and enthusiasm for this subject into an amazing web site, MiGMan's Flight Simulation Museum. If you like airplanes, you will really enjoy exploring this site.

Recently MiGMan was invited to share his flight sim expertise with a much wider audience on the ABC Australia television show Good Game, where he talked about the joys of flight simming and gave a brief "master class" on the key points of takeoffs, aerial combat, and landing. Visit the museum to learn more and to view a nice streaming video (WMV) of his flight sim segment on Good Game. Excellent stuff!

Orbiter Web: ar81 and Creative Orbitology

There are a number of creative and generous artists, software developers, teachers, and others who have contributed add-ons, scenarios, tutorials, and other things to the world-wide Orbiter community. One of the most creative and prolific is José Pablo Luna Sánchez, known as "ar81" on the Orbiter forums (3089 posts?!) and at Orbit Hangar. Pablo is a teacher who believes that young kids are smarter than you think, and he has taught many of his students to fly the Delta Glider in Orbiter (he even wrote a tutorial for this, to help others who wish to teach young kids). When he learned how to create and modify objects to improve and create planetary bases in Orbiter, he created some, and also created tutorials on how to do your own base modifications. His tutorials are always carefully organized and well written (he sometimes worries about English since it is not his first language, but his writing is excellent).

Pablo later expanded into modifying and creating add-ons, again contributing useful tutorials on such topics as using Vinka's spacecraft.dll modules. Moving beyond this, he developed something called Space Orbinomics, a space commerce game that is somehow linked to Orbiter (it looks cool but I've never tried it myself). Recently he created Mesh Wizard, a utility to help other add-on developers to visualize and work more easily with 3D "mesh" files. He has developed other utilities such as the Shuttle Fleet Launch Scenario Generator, and probably others as well. Most recently he posted an excellent tutorial (picture above) on using the free 3D modeling/animation tool Anim8or, the most common tool used by Orbiter add-on builders. He also contributed a cool "proof of concept" graphic novel using Orbiter graphics to illustate a brief adventure story.

You can find all (most?) of his Orbiter-related creations by searching for author ar81 at Orbit Hangar. Thanks to Pablo for all his contributions to the Orbiter community.

P.S. Unrelated except for the fact that I'm writing this while drinking a cappuccino at a Panera bakery/cafe in upstate New York, but Panera has free Wi-Fi at many of its US locations. Fast too.