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In this Q&A with James Gosling, find out more about the role of Java in the Mi
ssion to Mars and download your own version of the Maestro application. 

Friday Jan 16, 10:00 AM PT

Q:What exactly is Java's role in the Mars Rover mission? 

A: The places where NASA scientists have used Java for this mission is all on 
the ground side right now. They have created this collaborative command and co
ntrol system called Maestro, which does this combination of data visualization
, collaboration, command and control. It lets them look at images and create 3
-D reconstructions of terrain. It allows various experimenters to look at the 
scenes and topography, browse the image databases and take part in all the par
ticipation they need to do. And to do it in a remote, distributed and collabor
ative kind of way - so they could actually have scientists at institutions all
 over the world who are not only looking at the data, but also collaboratively
 deciding on the way the mission should proceed. One of the nice things that t
he JPL guys have done is that they've made a "cleaned up for civilians" versio
n of this application available that's called Maestro. 

Q:How is the Java assisting in controlling the Rover from earth? 

A: There's a Java API called Java Advanced Imaging, that's used for the images
 captured by the panoramic camera - the one that producing images with excruci
ating detail. Those panoramas are being created by combining images from two d
ifferent cameras onboard the Rover, so with the two lenses they get two images
 - just like you've got two eyes - so you can do a stereoscopic mapping where 
your brain is able to figure out how far away things are. Because they've got 
these stereoscopic images, they can go through a process that's called stereo-
image correlation, so they can calculate for each pixel in the image how far a
way that picture element really is. 

With this information, the JPL scientists can calculate how far away each rock
 is, each picture element, for all of the millions of pixels in one of these l
arge images. So you can get the depth of the image at every point. That's what
 a stereo camera gives you. When you've got the depth information, you can the
n actually build a 3-D model, the actual model of the terrain. And then you ca
n actually map the image back onto the 3-D model. So then what you've got is a
 colored, three-dimensional model of the world around you. 

Q:Are they actually commanding the Mars Rover with Java? 

A: For the command and control system, big parts of it are this rather large J
ava application. There are a lot of parts involved in this. The Rover itself h
as a computer onboard. There's no Java in that computer now. But on the ground
-side, there are a number of parts of the whole command and control chain that
 goes out to the Rover that's done in Java. It's not like every last piece of 
every subsystem is based on the Java code. Great big pieces of it are. In part
icular, all the data visualization, user interface front-end stuff and I belie
ve a whole lot of the database stuff is. 

Q:How does the public version of the Maestro application work? 

A: If you go to the Maestro website (http://mars.telascience.org), You will fi
nd that they've got two sets of downloads. One is the Maestro application itse
lf, and the other is a first teaser set of data from Mars. There are different
 versions for different platforms. There's one for Solaris, a version for Linu
x, there's a version for Windows and more. The fact that they've got all those
 versions just shows you how portable Java is, how cross-platform it is. It's 
exactly the same program in all of those, they are just packaged differently. 


So when you download the first set of data. There's a script that walks you th
rough looking at some of the data. Using the 3-D model they have there, and us
ing your mouse, you can actually manipulate the 3-D model and you can get a vi
ew as if you're standing off to the side of the landing looking back at it. Yo
u can actually wander around the landing site. You can see the rocks. You can 
see one of the places where one of the air bags didn't deflate completely. All
 of this 3-D, walk-through visualization is using standard Java APIs like Java
 3-D API, Java Advanced Imaging API, Java networking APIs and the user interfa
ce APIs. 

Using the Maestro version they are distributing, not only do you see a 3-D mod
el of the terrain, you see a 3-D model of the Rover. You can actually drive th
e Rover on this simulated terrain. It has this "video game" aspect to it. Exce
pt that you're actually driving it on a terrain model that's real. It's real M
ars data that's constructing this terrain. It's not like playing Dune, where y
ou're going through this maze that's completely fictitious. 

Q:How has it been to work with the JPL scientists on this project? 

A: I've spent a good amount of time down there with JPL, not only interacting 
with some of them, but I'm also on one of their advisory boards. In terms of t
alent density, IQ points per square meter, it's just an amazing place. Plus, t
hey are doing things that most people would think of as science fiction. Most 
people read science fiction stories about driving dune buggies on Mars. These 
guys actually build them. They actually know how to fly between the planets. I
've spoken to some of the guys that do interplanetary navigation, and that is 
really spooky stuff. You actually have to pay attention to relativity, the fac
t that time is not a constant - the faster you go, the slower things are. They
 function in a world where relativity actually matters. They are way outside o
f Newtonian mechanics. 

JPL is a place to go to have your mind blown - partly, because they are really
 charged up about what they do. This is a crowd of people who are living a dre
am. What they are doing is so out there, so wonderful. They are doing somethin
g that is very heroic, noble, exploratory and exciting. They are the only part
 of the U.S. government that I can really get excited about. NASA has this inc
redible public outreach program, because they know that they are loved and it'
s a tremendous public service. They do lots of stuff with schools. The fact th
at they put this stripped-down version of Maestro out there is a wonderful pie
ce of public outreach. 

Q:What is it about Java that makes it so attractive to this type of applicatio
n? 

A: The answer is there's a bunch of things, not just one thing. One of the asp
ects of Java that was really important to them is that it runs on a lot of pla
tforms. If you look at JPL, they've got Solaris boxes, Linux boxes, Windows bo
xes, Apple boxes - it works on all of them. If you look at the standard availa
ble API libraries available for Sun, there's a huge toolkit of things that you
 bring to bear. There are things like the 3-D modeling APIs, the Advanced Imag
ing APIs, and all the user interface APIs and networking APIs. The JPL guys us
ed all of them. They were able to leverage all of these standard tools. 

Plus, there's been a lot of experience with Java where folks have measured thi
ngs like developer productivity. For example, if you compare how long it takes
 someone to develop a piece of software in Java versus C or C++, essentially a
ll of the measurements show it to be about twice as effective. So if it takes 
some team of engineers ten months to do something in C++, it will take them fi
ve months to do it in Java. For an outfit like JPL that does everything on a s
hoestring budget, that also means you can trim it down five months - or still 
do it in ten months, but trim it down to half as many people. 

There are also a number of aspects to Java that are all about building more re
liable applications. It is a lot easier to build things that are more reliable
 - that break less often - so you don't have to worry about blowing your machi
ne to bits. There's also a lot in Java that's all about security. So when you'
ve got something like their large databases - whose integrity is something the
y need to be careful about - security is important. So, it's a whole bunch of 
things that all swirl together. Whenever you talk to Java developers, you get 
a different answer to the "why did you do it Java" question. Although, there t
ends to be a standard set of themes. 

Q:Is this the first time that Java has been used for this type of application 
- being beamed out into space? 

A: Actually, I don't think so. I've talked to people that have been doing vari
ous things with satellite ground station control and people that control syste
ms for giant telescopes. People are doing stuff like this all over the place. 
The JPL project is what people tend to talk about because it's too damn cool f
or words. 


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Java Technology and the Mission to Mars
By Dr. James Gosling
CTO, Developer Programs
Sun Microsystems 

Monday Jan 5, 4:00 PM PT

This weekend I saw what has to be the coolest Java(TM) app ever. We talk about
 "Java everywhere," which usually means Java(TM) technology in vehicle navigat
ion, imaging, control consoles and things like that. This time "everywhere" me
ans all of that and then some, because Java technology is playing a big role i
n NASA's latest, highly successful, Rover Mission to Mars. 

On Saturday night I watched as a control room full of immensely tense geeks ex
plode with joy as they successfully landed the six-wheeled Mars Rover "Spirit"
 on the planet's surface. From there, scientists at NASA's Jet Propulsion Labo
ratories in Pasadena will get to use their powerful, Java technology-based, gr
ound side control system to maneuver Spirit on the Martian terrain in what has
 to be the most amazing network "video game" in history. 

Java 3D and Java Advanced Imaging technology are also key to the software JPL 
is using to render and interpret realtime images captured by the Rover. NASA h
as even made a stripped down version of the software that you can download so 
you can view a simulated 3D landscape and drive the Rover around in it. 

There are all kinds of reasons JPL is using Java technology for control and im
aging systems for the Rovers. NASA engineers had access to hundreds of special
ized APIs and network protocols that they needed to bring this off. They got g
reat productivity and reliability. The data they're collecting through this pr
ogram is part of a distributed, collaborative network of scientists and engine
ers, and the ability of Java technology to run on any platform enables a secur
e, reliable global dialogue within NASA's scientific community. 

Now that Java has helped us get to Mars, who knows what "Java Everywhere" will
 mean in the future?


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