...Phoenix Launch...The Search for Life on Mars begins in 24 days !!!

The rovers and other observers have been a search
primarily for signs of water on Mars for obvious
reasons. But the rovers lacked the equipment
for tests of life. Phoenix takes the next step.


Phoenix Mar Mission Home
http://phoenix.lpl.arizona.edu/


"The Phoenix lander is going to an area of Mars where water
is believed to exist in the form of ice just below the surface.
This water ice is probably spread fairly uniformly throughout
the northern plains so the lander should be able to uncover
ice wherever it lands."
http://phoenix.lpl.arizona.edu/faq.php


"On the deck, miniature ovens and a mass spectrometer, built
by the University of Arizona and University of Texas-Dallas, will
provide chemical analysis of trace matter. A chemistry
lab-in-a-box, assembled by JPL, will characterize the soil
and ice chemistry. Imaging systems, designed by the University
of Arizona, University of Neuchatel (Switzerland) (providing an
atomic force microscope), Max Planck Institute (Germany) and
Malin Space Science Systems, will provide an unprecedented
view of Mars-spanning 12 powers of 10 in scale.
The Canadian Space Agency will deliver a meteorological station,
marking the first significant involvement of Canada in a mission
to Mars."
http://phoenix.lpl.arizona.edu/mission.php


Science Objectives

Objective 2: Search for Evidence of Habitable Zone and Assess
the Biological Potential of the Ice-Soil Boundary

"Recent discoveries have shown that life can exist in the most
extreme conditions. Indeed, it is possible that bacterial spores
can lie dormant in bitterly cold, dry, and airless conditions for
millions of years and become activated once conditions become
favorable. Such dormant microbial colonies may exist in the
Martian arctic, where due to the periodic wobbling of the
planet, liquid water may exist for brief periods about
every 100,000 years making the soil environment habitable."

"Phoenix will assess the habitability of the Martian northern
environment by using sophisticated chemical experiments to
assess the soil's composition of life giving elements such as
carbon, nitrogen, phosphorus, and hydrogen. Identified by
chemical analysis, Phoenix will also look at reduction-oxidation
(redox) molecular pairs that may determine whether the potential
chemical energy of the soil can sustain life, as well as other
soil properties critical to determine habitability such as pH
and saltiness."

"Despite having the proper ingredients to sustain life, the Martian
soil may also contain hazards that prevent biological growth, such
as powerful oxidants that break apart organic molecules. Powerful
oxidants that can break apart organic molecules are expected
in dry environments bathed in UV light, such as the surface of Mars.
But a few inches below the surface, the soil could protect organisms
from the harmful solar radiation. Phoenix will dig deep enough into
the soil to analyze the soil environment potentially protected from
UV looking for organic signatures and potential habitability."
http://phoenix.lpl.arizona.edu/science03.php


And two great videos at this site.

Scroll down and watch the rough cut entry, descent
and landing video. The landing looks rather risky eh?

And just below that video is a wonderful collection of
various water features on Mars, comparing valley networks
deltas, channels, oxbows etc between earth and mars.
http://phoenix.lpl.arizona.edu/videos.php


s

In article ,
Jonathan wrote:
Scroll down and watch the rough cut entry, descent
and landing video. The landing looks rather risky eh?

And if the video isn't enough to make you nervous, consider that the
lander chassis is essentially a duplicate of that of the late lamented
Mars Polar Lander.

(There was a second lander under construction, with a different payload
but the same chassis design, meant for launch in 2001. It was grounded
after MPL was lost, and then canceled altogether. The chassis was one of
the assets made available to the competitors in the first Mars Scout
competition, which Phoenix won.)

There's a reason why the lander is called Phoenix, and it's not because
the Principal Investigator is from U of Arizona... :-)
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

Henry Spencer wrote:


There's a reason why the lander is called Phoenix, and it's not because
the Principal Investigator is from U of Arizona... :-)

UofA has a pathological hatred for the Phoenix area, especially Tempe.
They are bitter for the many times Sparky has kicked Wilbur's butt.

Hop

(Henry Spencer) wrote:

In article ,
Jonathan wrote:
Scroll down and watch the rough cut entry, descent
and landing video. The landing looks rather risky eh?

replying to Johnathan.

Not particulary, no. Mind you, there isn't actually an 'unrisky' way
to land on another planet. (And before you bring it up, no - airbags
are risky too.)

And if the video isn't enough to make you nervous, consider that the
lander chassis is essentially a duplicate of that of the late lamented
Mars Polar Lander.

Why would that make you nervous? The failure of MPL wasn't a design
error so far as we know.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

It would make Me feel better if We had images of the crash site. It
has been search for but never imaged. Pictures might help in the
investigation of the cause of the failure. The fault tree
investigation showed it to be the early engine shut down. I would hope
that that does not happen again. This will be the first attempt at
life science since the failed Beagle mission. That too was a shame to
have lost.

Carl

On Jul 10, 9:18 am, surfduke wrote:
It would make Me feel better if We had images of the crash site. It
has been search for but never imaged. Pictures might help in the
investigation of the cause of the failure. The fault tree
investigation showed it to be the early engine shut down. I would hope
that that does not happen again. This will be the first attempt at
life science since the failed Beagle mission. That too was a shame to
have lost.

Carl

AW&ST had a good article within the past couple of weeks about
Phoenix. Regarding the old chassis, one of the project people
discussed how the Better Quicker Cheaper mantra led to the skipping of
testing. That testing has been on Phoenix, and not surprisingly, they
found stuff that could have resulted in the vehicle having a bad day,
that they subsequently fixed. The article also discussed that they
have retargeted the vehicle once already due to imagery that said the
landing area first selected was too rough.

Find the article . . . there is an awesome picture of water being run
under high pressure being run through the landing rocket system to
find leaks. I was surprised that water was used . . . and amazed at
the efflux from the 12 engine nozzles.

Take care . . .

John

In article .com,
John wrote:
...Regarding the old chassis, one of the project people
discussed how the Better Quicker Cheaper mantra led to the skipping of
testing.

Note, however, that according to people who were the

"All customary and prudent steps were executed in the development
process... After examination of the contributing factors, there is no
evidence that [faster/better/cheaper] concepts caused the MPL failure."

A test that would have detected the touchdown-sensor problem *was done*.
It had to be interrupted in the middle due to another problem, and they
decided to pick up from where it left off, rather than starting over from
the beginning. The picking up from where it left off, alas, didn't quite
reinitialize things to the exact previous state, and so the problem was
missed.

(Ref: Euler et al, "The failures of the Mars Climate Orbiter and Mars
Polar Lander: a perspective from the people involved", Advances in the
Astronautical Sciences 107 (Guidance & Control Conference 2001).)

Similar testing mistakes have killed slower/worse/costlier megaprojects;
Galileo, one of the slowest and costliest planetary-probe projects ever,
made several such mistakes, although by good luck none was fatal. There
is no rational reason to blame the MPL loss on faster/better/cheaper
(unlike the loss of MCO, which pretty definitely *was* due to the
compressed schedule and shortage of manpower).
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

Derek Lyons wrote:
Why would that make you nervous? The failure of MPL wasn't a design
error so far as we know.

Yes it was; the sensors on the vehicle interpreted the vibration of
landing gear extension as touchdown, and shut down the landing rockets
while it was still quite a ways in the air.
That at least needs to be fixed.

Pat

"Pat Flannery" wrote in message
...


Derek Lyons wrote:
Why would that make you nervous? The failure of MPL wasn't a design
error so far as we know.

Yes it was; the sensors on the vehicle interpreted the vibration of
landing gear extension as touchdown, and shut down the landing rockets
while it was still quite a ways in the air.
That at least needs to be fixed.



The timeline for this landing shows the legs being
extended at 12km, some 2 minutes before the
engines start firing. Maybe that's the fix.
http://uplink.space.com/attachments//693625-mars.jpg


This article says the MPL engines shut off at about
130 feet when the legs were extended.
http://www.space.com/missionlaunches...mpl_clues.html


Just after the crash Lockheed lamely tried to blame
it on Nasa, saying they sent the thing into a huge
canyon and it tumbled down the walls. What a
bunch of back-stabbers.
http://www.space.com/scienceastronom...sh_000106.html


After reading the above article, I don't trust much that
Lockheed says. They seem like a bunch of finger
pointers that'll jump at the first cause that gets them
off the hook.

Then Lockheed had an outside firm look for any software bug
that might have caused its failure. And the contractor said
they found it in only 12 hours.
http://www.t-vec.com/clients/nasa1.php

According to Wikipedia there's a second possible cause.

"Another possible reason for failure was inadequate preheating of
catalysis beds for the pulsing rocket thrusters: hydrazine fuel
decomposes on the beds to make hot gases that throttle out
the rocket nozzles; cold catalyst beds caused misfiring
and instability in crash review tests."
http://en.wikipedia.org/wiki/Mars_Polar_Lander


And here we get some better answers.

"The panel found that NASA conducted a pre-launch test
of the landing rockets but that the sensors did not
generate the touchdown signals as was intended.

It traced the lack of signal to faulty wiring of the sensors.
After the sensors were rewired, NASA did not repeat
the testing that would have unmasked the software
problem."

"Young's panel concluded a 30 percent underfunding
of the Polar Lander mission prompted NASA to cut
back on personnel as well as the ground testing that
would have uncovered the design flaws and lack of
communications gear. "
http://www.chron.com/content/interac...er/000329.html


Hey, this is getting better by the minute~

James Oberg of UPI accused NASA of knowing about a flaw
in advance and covering it up. Members of the review team responded
with terms like... "bunk," "complete nonsense," and "wacko," to
describe their reactions to UPI's charge.
http://marsweb.jpl.nasa.gov/msp98/news/news69.html


I think they protest too much!


So now, the accusation is that the cold temperature testing
showed a flaw, so they covered up that data. The response
isn't all that comforting.


Finding 1: MPL's braking thrusters did not fail acceptance
testing due to low temperatures.The situation described
in the UPI article could not have occurred because
no low-temperature acceptance or qualification
tests were conducted
http://www.hq.nasa.gov/office/oig/hq...sments/MPL.pdf


What tests? Sheez!

I wonder which shredder those cold temperature
tests ended up in? Oh well, as long as Phoenix
makes it ok all will be forgiven.



s









Pat

In article ,
Pat Flannery wrote:
Why would that make you nervous? The failure of MPL wasn't a design
error so far as we know.

Yes it was; the sensors on the vehicle interpreted the vibration of
landing gear extension as touchdown, and shut down the landing rockets
while it was still quite a ways in the air.

Correction: the misinterpretation was in the control software, not in the
sensors. The software quite correctly wasn't paying attention to the
touchdown sensors at all at leg deployment time. Unfortunately, the
transient false touchdown indications set "touchdown detected" flags, and
nothing cleared those flags before the final-descent code started paying
attention to them. (During the one full-descent-sequence test, nothing
untoward happened during leg deployment... but the test had to be
interrupted before the final-descent phase started, and the procedure
used to restart the test had the unfortunate side effect of clearing
the touchdown-detected flags.)

The problem with the sensors showing transient false touchdown indications
during leg deployment actually *was known*, incidentally, just not to the
software people. They hadn't been close enough to the hardware work to
hear about the problem, and the specs they'd received for handling those
sensors didn't say anything about transient rejection or data filtering.
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