Mars Rover Controlled By Java

[mitch]

Local atmospheric pressure is 7-10 torr. Earth sea level is 760
torr. How many planes do you know that cruise at 100,000 feet absent
any oxygen at all? Martian aircraft are a bad dream.

Hmm. Then the test of a Mars glider plane back in August of 2001 was
just a bad dream? ;-) Work has begun on a propellered version of the
glider cited below. Enjoy.

--mitch
----------------------------

http://amesnews.arc.nasa.gov/releases/2001/01_58AR.html

Michael Mewhinney Aug. 13, 2001
NASA Ames Research Center, Moffett Field, CA
Phone: 650-604-5026 or 604-9000
(e-mail address removed) or (e-mail address removed)


RELEASE: 01-58AR

AMES COMPLETES SUCCESSFUL TEST OF MARS AIRPLANE PROTOTYPE

Soaring gracefully down to Earth from a balloon floating 101,000 feet high
above Oregon, a NASA prototype of an airplane that someday may fly over
Mars successfully completed a high-altitude flight test this week.

Conducted at Oregon's Tillamook airport by the Kitty Hawk 3 project at NASA
Ames Research Center, Moffett Field, CA, the test was designed to validate
the aerodynamic performance of the prototype. Nicknamed "Orville" after
one of the famed Wright brothers who first flew on Dec. 17, 1903, the NASA
731 glider was dropped from a helium-filled balloon that towed it up to an
altitude of 101,000 feet - the highest ever for such a test - before
releasing it. Engineers and scientists hailed the test as a great success.

"It was a great flight and everything went really well. It appears that we
realized all of our test objectives," exclaimed a jubilant Andy Gonzales,
an Ames aerospace engineer who served as the flight test director.
Low-altitude tests of NASA 729, another prototype called "Wilbur," were
conducted last month at Ames.

"Mars has always fascinated people," said Larry Lemke, an aerospace
engineer at NASA Ames who serves as Ames' project manager for advanced Mars
mobility concepts, which include airplanes as well as other systems.
"Every time we send a mission up there, we come back with fascinating
discoveries."

According to Lemke, a Mars airplane is an idea whose time has come. "The
Mars airplane is an idea that has been around for about 25 years, and over
the past five years or so, it has been growing in popularity," he said. "I
think a Mars airplane will play a role in exploring the Red Planet."

Conventional in appearance, the Mars airplane concept developed by Ames
engineers features a long, straight wing and twin tails in the rear. The
remote-controlled glider tested in Oregon featured an approximately
four-foot-long fuselage and an eight-foot wing span.

"The flying we have successfully completed in Oregon is very similar to the
flying that we will be doing over Mars during a productive exploration
mission," Lemke said. "One unique aspect of flying a Mars mission with an
airplane is that it must be constructed in a fold-up configuration in order
to fit inside a spacecraft."

In its future configuration for Mars, the aircraft is expected to have its
own propeller propulsion system capable of operating in the Mars
atmosphere, which is comprised mostly of carbon dioxide. It will also
carry a variety of sophisticated instruments to observe and conduct science
experiments.

"The possibility of life on Mars is a very hot topic and an interesting
question, so I'm sure you will find instruments on board that are designed
to find signs of water on Mars, which is necessary for life," Lemke said.

"In addition, we would have a large array of cameras on the airplane to be
able to see large areas of the Mars terrain in very high resolution," Lemke
said. He said the cameras aboard the aircraft would be so precise, they
could see objects on Mars as small as the size of a quarter. "I think the
images will be stunning," he said. "During a Mars airplane mission, we will
be able to view the planet at very close proximity and this will convey to
the public that there is a real planet there, not just an abstract."

"Our test flight at Tillamook airport showed the airplane's flight was very
smooth and stable which makes for a good platform for science instruments,"
said Gonzales.

Ames engineers predict the next few years will be challenging, as they
prepare for a potential mission to Mars. "We will be expanding the envelope
and developing a much more complex aircraft for exploring Mars," Lemke
said. The next step will be to develop a Mars airplane model with folding
wings and later, one with a propeller propulsion system.

-- end --

Note to Broadcasters: A video file related to this news release is
scheduled for distribution via satellite on NASA Television on August 14,
2001. Because feed times and the schedule are subject to change, please
check the NASA TV video file line-up on the web at
ftp://ftp.hq.nasa.gov/pub/pao/tv-advisory/nasa-tv.txt

NASA TV is available on GE-2, transponder 9C at 85 degrees west longitude,
with vertical polarization; frequency is on 3880.0 megahertz, with audio on
6.8 megahertz. For general questions about the video file, call NASA
Headquarters, Washington, DC: Fred Brown at 202/358-0713

 

[Uncle Al]

Hmm. Then the test of a Mars glider plane back in August of 2001 was
just a bad dream? ;-) Work has begun on a propellered version of the
glider cited below. Enjoy.

AMES COMPLETES SUCCESSFUL TEST OF MARS AIRPLANE PROTOTYPE

The empirical fact is that lowland Martian air pressure is 7-10 torr.
The is equivalent to 120,000-100,000 feet terrestrial altitude. If
the silly thing will be diddling at even 1000 ft altitude Martian, the
air will be thinner. I don't care if Hillary Ramrod Clinton left a
big warm wetspot on the chute prior to deployment. Stuff doesn't fly
that high - certainly absent oxygen in the intake.

"Ye canna break the laws of physics."

The Concorde flew at 60,000 feet and gulped air like a madman. The
U-2 did 75,000 feet, breathed air, and it was a bitch to fly. The
SR-71 Blackbird could barely do 100,000 feet while at Mach 3+ with its
cockpit windshield simmering at 620 F. It drank 8000 gallons/hr of
fuel. It breathed 6 million ft^3 of air/minute.

Soaring gracefully down to Earth from a balloon floating 101,000 feet high
above Oregon, a NASA prototype of an airplane that someday may fly over
Mars successfully completed a high-altitude flight test this week.

Yeah, right. They have an airfoil that works in vacuum. What is its
payload - one NASA decal? Learn the difference between Official Truth
and real world truth.

[snip]

 

[Rupert Pigott]

[SNIP]

The empirical fact is that lowland Martian air pressure is 7-10 torr.
The is equivalent to 120,000-100,000 feet terrestrial altitude. If
the silly thing will be diddling at even 1000 ft altitude Martian, the

According to that link they've tested it at over 100,000 ft
already. Cute idea, but I figure the air-ship type option
may be more robust and easier to deploy - plus if something
momentarily breaks it's less like to fall out of the sky.

Cheers,
Rupert

 

[Andrew Thompson]

"Rupert Pigott" <[email protected]>
wrote in message | |
| [SNIP]
|
| > The empirical fact is that lowland Martian air pressure is
7-10 torr.
| > The is equivalent to 120,000-100,000 feet terrestrial
altitude. If
| > the silly thing will be diddling at even 1000 ft altitude
Martian, the
|
| According to that link they've tested it at over 100,000 ft
| already. Cute idea, but I figure the air-ship type option
| may be more robust and easier to deploy - plus if something
| momentarily breaks it's less like to fall out of the sky.

This topic was discussed recently on sci.space.tech.
One of the problems identified for heavier than..
atmosphere craft was the *runway length required
to take-off or land.

[ And to those that would jump in and suggest
keeping it aloft continuously, that is impractical
with sandstorms, ..even assuming you could squeeze
a 'little' RTG into it, and still get it off the ground. ]

Balloon, or better still, orbiter with a bloody
good telescope. No dust, no sand, no runways
to deal with and you can cover far more area.

* Well, of _course_ they would be using all
those really _long_ runways built on Mars
during WWII. ;-)

 

[Michael N. Christoff]

You know, believe it or not, Java isn't all that slow. Here are a
couple of tests comparing different languages for very simple
algorithms:

http://www.bagley.org/~doug/shootout/index2.shtml

http://osnews.com/story.php?news_id=5602

While these simple tests might not hit on some of the weaknesses of a
JIT language like Java, they do tend to indicate that the performance
for most tests isn't all that bad.


That being said, the fact remains that Java is NOT being used on Mars
today. The Java stuff the original article talked about was all
earth-based stuff. In fact, it wasn't even the thing that was getting
the data from the Mars rover, simply the component that let people
view the data after it had been received.

The code on the rover wasn't specified, but it's most likely C/C++ as
that is the primary development language for Wind River VxWorks. I'm
not even sure if that OS has Java support, though even if it did it
would be a BAD choice. Java is NOT designed with real-time operating
systems in mind.

That is correct. However, standard Java is also not a good choice for cell
phones. You need Java Micro edition (J2ME) for this. On that note, there
is much work being done on developing a version of Java for real time
systems.



l8r, Mike N. Christoff

 

[Jan Panteltje]

You know, believe it or not, Java isn't all that slow. Here are a
couple of tests comparing different languages for very simple
algorithms:

OK, but my latest test on THAT java mars rover soft ran 1.3 frames / second

from the rovers will be provided and can be loaded into the program.

http://mars.telascience.org/home/

"The Jet Propulsion Laboratory has released Maestro, a public version
of the primary software tool used by NASA scientists to operate the
Mars Exploration Rovers. Anyone can download Maestro for free from
http://mars.telascience.org/ and use it to follow along with the
rovers' progress during the mission. You can use Maestro to view
pictures from Mars in 2D and 3D and create simplified rover activity
plans. During the mission, updates will be released for Maestro
containing the latest images from Mars."

Me replying:
OK I downloaded the Linux version last night (I am in Europe),
realizing after it turned out to be a 2 1/2 hour download on a V90 modem,
that I really must be confident that lander worked this time....

Anyways it is based on java rle, the install script has some errors,
so you can not run it as the indicated executable,
but I had to run it as (I untarred it in /video/compile/maestro/ )
/video/compile/maestro/R2004_01-Public-Linux/JPL/SAP/bin/WITS
while 'SAP', that should start it (in /usr/local/bin), points to
SAP -> /video/compile/maestro/R2004_01-Public-Linux/WITS

So directory JPL/bin is missing from the softlink in /usr/local/bin
Also the install script 'forgets' to do
tar -xvf mer.tar
in
/video/compile/maestro/R2004_01-Public-Linux/JPL/SAP/WITS-db
so that you actually see some data.
Because of java (likely) the thing is slower then a dead snail glued with
superglue to a scrapped Apollo.
I followed the intro to the point where it had to move to a target, then it
froze with this message in the console:

An unexpected exception has been detected in native code outside the VM.
Unexpected Signal : 11 occurred at PC=0x400C32F7
Function=memcpy+0x27
Library=/lib/libc.so.6

Current Java thread:


****************
Another exception has been detected while we were handling last error.
Dumping information about last error:
ERROR REPORT FILE = (N/A)
PC = 0x0x400c32f7
SIGNAL = 11
FUNCTION NAME = memcpy
OFFSET = 0x27
LIBRARY NAME = /lib/libc.so.6
Please check ERROR REPORT FILE for further information, if there is any.
Good bye.

So, 1.3 frames / second before it crashed, and this system plays live video
at normal speed no problem.
But THAT code is written in asm and C.
I remember the old vrml browsers (was there al the way from the beginning).
After some of these got ported to Java it was a factor 10 slower (at least).
And NO reason in the world to do that, portability of good C code is excellent.
Java is a mistake.

 

[Jan Panteltje]

since hardware speed grows very quick, it is not a real problem!

Ridiculous
10 years behind always on asm and C

 

[Richard Heathfield]

since hardware speed grows very quick, it is not a real problem!

Past performance is no guarantee of future success. Those who live by
Moore's Law will, ultimately, die by it.

 

[Jon Leech]

Local atmospheric pressure is 7-10 torr. Earth sea level is 760
torr. How many planes do you know that cruise at 100,000 feet absent
any oxygen at all?

The AeroVironment Helios Prototype, for one:

http://www.aerovironment.com/area-aircraft/unmanned.html

Martian aircraft are a bad dream.

No more than Mars sample return or numerous other challenging but
entirely feasible tasks.

Jon
__@/

 

[Alan Balmer]

Java is the worst thing that could happen to computing since the
invention of the chuwing gum hard disk.
It is slow, slow, slow, slow, SLOW, and not to mention slow.
And on top of that it is slow.

Haven't tried it lately, have you ;-)

 

[Stefan Monnier]

Java is the worst thing that could happen to computing since the

invention of the chuwing gum hard disk.
It is slow, slow, slow, slow, SLOW, and not to mention slow.
And on top of that it is slow.

And that's why it's such an important step forward: it makes it possible for
people to realize that speed is not all that important when choosing
a programming language.

Now that we've taken this step, we can start to think about the next step:
focus on safety and correctness.


Stefan

 

[Ashlie Benjamin Hocking]

And that's why it's such an important step forward: it makes it possible for
people to realize that speed is not all that important when choosing
a programming language.

Now that we've taken this step, we can start to think about the next step:
focus on safety and correctness.

Actually, speed is very often an important aspect. The question is,
speed of what? If you spent five days writing/debugging a program in
C++ that could be written in two hours in LISP (for example), and the
program is only going to be used for a single experiment or set of
experiments, than most likely the improvement in performance that you
got by writing it in C++ is offset by the time spent writing/debugging
it. Obviously, as been said several times, it depends on what the
language is being used for. If the software is for security-critical
uses, C++ is probably a bad choice. If the software is for cracking a
particular encryption algorithm, C might be a very good choice. (Of
course, assembly might be even better!)

---------------------------------------------------------------------
| "Good and evil both increase at compound
Ben Hocking, Grad Student | interest. That is why the little
(e-mail address removed) | decisions you and I make every day are of
| such infinite importance." - C. S. Lewis
---------------------------------------------------------------------

 

[Jan Panteltje]

Haven't tried it lately, have you ;-)

Oh yes I did, but nervous Jave people start spamming my email
that I really *should not mention Java is slow*, well, read my other post
in this tread.
And THAT was written by NASA.
Penty of stuff around to show it, get real.
mmm
Solutions of Yesterday already NOW on your desktop with JAVA (snailmark).
Sorry

 

[Jan Panteltje]

And that's why it's such an important step forward: it makes it possible for
people to realize that speed is not all that important when choosing
a programming language.

Now that we've taken this step, we can start to think about the next step:
focus on safety and correctness.


Stefan

How safe is a car that cannot accelerate (when needed).
How correct is a solution that runs 10x slower then other ones.
(like web browser).
What does it give us, so you cannot program with pointers, so
you do not want to learn that, so you use java.
Popups, webcrap...
Or use 10 x power for the same final speed, efficient?
Java is as safe as the one who programs with it.
If you forget (because you think it is so safe) about any security issues,
then your eventual lack of knowledge about these issues will break
your code security.
I cannot really think of one useful application of Java except
burning it.
It is like BASIC, except slower, and less used.
Hey I am not just pestering, it is TRUE.
NOTHING is slower then java.

 

[Stefan Monnier]

How safe is a car that cannot accelerate (when needed).

How correct is a solution that runs 10x slower then other ones.
(like web browser).
What does it give us, so you cannot program with pointers, so
you do not want to learn that, so you use java.
Popups, webcrap...
Or use 10 x power for the same final speed, efficient?

Why don't you go and learn about programming languages (and their history)?


Stefan

 

[seemanta dutta]

Why mention oxygen specifically?
The solar panels mentioned would have no
problem with the complete absence of oxygen.

My dear friend, planes need atmosphere not only for combustion but
also for generating the required lift by its wings or copter blades or
whatever. A rarefied atmosphere would not be able to generate enough
lift at a decent velocity like on earth. of course by increasing the
velocity several times we can generate some lift, but that would be a
totally wasteful use of energy.

Besides to keep a copter in the air it woulf consume a great deal of
energy which could be otherwise utilised for some other purpose.

..Though a battery powered chopper would
still be little more effective than one that
uses internal combustion.

again battery power does not solve the probelm of generating enough
lift in a rarefied atmosphere.

regards,
Seemanta Dutta

 

[Michael Borgwardt]

My dear friend, planes need atmosphere not only for combustion but
also for generating the required lift by its wings or copter blades or
whatever.

So he is right: oxygen does not, specifically, matter.

A rarefied atmosphere would not be able to generate enough
lift at a decent velocity like on earth. of course by increasing the
velocity several times we can generate some lift, but that would be a
totally wasteful use of energy.

Don't forget that the necessary lift is *also* much lower on Mars
since it has only one tenth the mass!

 

[mmeron]

So he is right: oxygen does not, specifically, matter.


Don't forget that the necessary lift is *also* much lower on Mars
since it has only one tenth the mass!

Well, the gravity is not proporitonal to mass alone. It's radius is
smaller as well, so its gravity, on surface, is doen only by a factor
of 2 or so. Its atmospheric density, on the other hand, is down by
more than two orders of magnitude. So, the necessary lift is lower by
much less than the available lift.

Mati Meron | "When you argue with a fool,
(e-mail address removed) | chances are he is doing just the same"

 

[Ken Hagan]

Would it be *on-topic* to query the relevance of this to...

comp.arch
comp.distributed
comp.lang.java
comp.lang.java.programmer
comp.object
comp.programming
comp.theory
sci.physics

I'm all for serendipity and all that, and I've learned all sorts
of things from off-topic threads, but I think the OP's claim (and
hence the official subject of the thread) was shot down with the
first or second reply and we've given aircraft and Java advocacy
a good run now.

 

[Jan C. =?iso-8859-1?Q?Vorbr=FCggen?=]

Newer Java versions and graphical applications using ie. SWT perform

the same as native C/Fortran applications. In fact, the new Hotspot
optimizer in 1.4 is quite good at numerical codes too.

While that is likely true, ...

For some large
scale computations, my Java codes perform identical to Fortran codes,

Really? Even if you compile with optimization?

with the added benefits of readability and maintainability, not to
mention trivial cross-platform deployment (from my desktop to the local
supercomputer, with excellent scalability).

I consider a reasonably well-written F95 program to be very maintainable
and more portable than Java - if only for the fact that there's only one
F95 standard all compilers are written to, while there are several
incompatible (in various ways) Java "standards" around, not to mention
the different thread semantics of different implementations.

I might add that Java w/Hotspot quite often outperforms vanilla C
codes, it's only when adding lots of optimization flags to the compiler
that the performance gap closes.

For any modern compiler of a 3GL language, not compiling with (the equivalent
of) -fast is grossly negligent.

Jan