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Rosco Bodine
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Mars lander Phoenix
In about six hours , Mars is getting a visitor.
http://phoenix.lpl.arizona.edu/
http://www.nasa.gov/mission_pages/phoenix/main/index.html
[Edited on 25-5-2008 by Rosco Bodine]
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MagicJigPipe
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I did some calculations and when the lander lands on Mars it will take 15 minutes for our radio signals to reach it which basically means it has a
response delay of 30 minutes because we are seeing images (from the craft) that happened 15 minutes ago.
So, if it were the situation where destruction of the spacecraft was 25min away, it would be screwed. I find that very fascinating.
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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JohnWW
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There is an on-board computer on the craft, which provides automatic correction for angle and velocity and orientation of approach, based on on-board
measurements of such things as velocity, altitude, position, direction of travel, and atmospheric pressure. This provides little need, if any, for a
manual override directed from Earth.
[Edited on 26-5-08 by JohnWW]
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MagicJigPipe
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I understand that, but some instructions are still needed, especially in case of emergency.
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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Rosco Bodine
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There's probably dedicated hardware logic and software running parallel to that to tweak the descent event sequence timing.
The onboard autopilot either gets it right, and the hardware does its job, or the whole plan is SOL
Martian gravity is predicted to one hundred per cent
reliably bring about the landing at some touchdown velocity. So really it is only a matter of auto-finessing
a gentle meeting of landing pads and martian surface
via an intelligent throttling of the descent engine, so
that the desired low rendezvous velocity is achieved
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Rosco Bodine
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Two minutes to entry of the Martian atmosphere
http://www.nasa.gov/multimedia/nasatv/
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Rosco Bodine
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Phoenix has soft landed on Mars.
http://phoenix.lpl.arizona.edu/
During the entry there was no blackout from atmospheric heating. Telemetry was uninterrupted during the entire descent, relayed to Earth by the Mars
Odyssey orbiter which was orbiting nearby overhead to the Phoenix lander. Odyssey is a still on station and functioning Mars orbiter from 2001.
http://mars.jpl.nasa.gov/mro/spotlight/20080523a.html
Image is Courtesy of NASA/JPL-Caltech
[Edited on 25-5-2008 by Rosco Bodine]
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JustMe
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Now just waiting for the Solar panels to unfurl (2 hour wait after touchdown), and for camera platform to rise up....
I haven't watched a "live" landing since Viking!
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Rosco Bodine
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All is well, the solar panels are deployed and pictures are coming in.
http://www.nasa.gov/multimedia/nasatv/
http://phoenix.lpl.arizona.edu/images.php?gID=0&cID=7
[Edited on 25-5-2008 by Rosco Bodine]
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chemoleo
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Very cool!
There almost seems to be some sort of regularity on the ground, hexagonal or pentagonal perhaps?
I wonder if they have landed on flood basalt - here on earth it sometimes leaves hexa/pentagonal columns, i.e. as in the Giants Causeway in Ireland,
or on many locations in Iceland.
Olympus Mons and the other Tharsis volcanoes are way more towards the equator, so I don't know if this makes sense...
So close to the pole, I wonder whether the probe will get impeded by CO2 precipitation during the Mars winter.... from what I remember it appears
during the winter and goes during the summer...
On the matter of water on Mars - check this on google Mars:
http://www.google.com/mars/#lat=28.574874&lon=-50.449218...
I really wonder what other process than water could cause such markings in the ground - this looks like canyon areas right from a plane!
Or look at this:
http://www.google.com/mars/#lat=11.135287&lon=-31.333007...
This looks like craters, that were leveled and flooded post impact - else why would their rims be leveled once intersecting with the flow valleys?
and this
http://www.google.com/mars/#lat=-8.363692&lon=-79.255371...
looks like what we see in any of earth canyons... this is infrared btw, and striations are inverted, light colours don't mean it's high but rather
illumination (and heating) by the sun.
Fascinating! I wish more human energy was spent on this rather than stupid wars, weapons and similar. Peace 
[Edited on 26-5-2008 by chemoleo]
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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JustMe
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The regularity (polygons), are believed to be evidence of the presence of a kind of permafrost (as you know water sublimes at that low pressure, and
creates these shapes).
Yes, carbon dioxide "precipitation" will cover the probe when winter comes, they expect it to be buried. Consequently the 90 day mission is REALLY a
90 day mission (unlike the rovers). Of course six months later they will send a signal to see if it did survive, but that is highly unlikely buried
under a the CO2. Batteries couldn't recharge so they will freeze along with the electronics. Still, y'never know.
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Rosco Bodine
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Well Odyssey has been patiently waiting seven years for her mate to arrive. The first mission was only half successful, as
a little metric to english measurement conversion error put the first lander into a crater at high velocity instead of a soft landing ......oops I believe it is the same one I was thinking about, where the guys with the slide
rules screwed the pooch and the soft landing turned into a spacecraft surface
impact penetration depth experiment instead. After that faux pas, then funding got cut and the mission was cancelled. But the spare probe was
reworked and launched (finally) to complete the mission, if I have the story right.
http://phoenix.lpl.arizona.edu/images/gallery/sm_140.jpg
[Edited on 25-5-2008 by Rosco Bodine]
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Sauron
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How long do you reckon before the luddite assholes in the world start websites "proving" that all this was really done on a Hollywood sound stage?
They are still saying that about Apollo 11.
I was 3.5 miles from the pad when Apollo 11 took off, that was in the press area 1.5 miles inside the danger zone. The blasts pulsed like a heartbeat,
and pushed me backwards from three and a half miles, like a hand planted in my chest. Unforgettable. I was 19 at the time.
Sic gorgeamus a los subjectatus nunc.
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Twospoons
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That must have been a hell of a sight, Sauron. I envy you.
Helicopter: "helico" -> spiral, "pter" -> with wings
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Rosco Bodine
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Water on Mars? You betcha!
This crater is 22 miles (35 km) wide and is about 1.2 miles (2 km) deep. The circular patch of bright material located at the center of the crater is
water ice that remains year round. Frost can also be seen along the rim of the crater. This unnamed impact crater is located on Vastitas Borealis, a
broad plain that covers much of Mars' far northern latitudes.
Crater Ice Pond
Photo credit: ESA
Date: 2006-08-22
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JohnWW
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| Quote: | Originally posted by JustMe
Now just waiting for the Solar panels to unfurl (2 hour wait after touchdown), and for camera platform to rise up. |
Because of the high latitude where it is on Mars, well within 25 degrees (the Martian obliquity of the ecliptic) of the north pole
which will be in darkness for much of the 6-month Martian winter, it will need more than solar power to keep it working for long. Does it have an
onboard radioisotope thermoelectric power source? (Any Martians there would certainly head south for the winter!).
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-jeffB
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| Quote: | Originally posted by JohnWW
Because of the high latitude where it is on Mars, well within 25 degrees (the Martian obliquity of the ecliptic) of the north pole which will be in
darkness for much of the 6-month Martian winter, it will need more than solar power to keep it working for long. Does it have an onboard radioisotope
thermoelectric power source? (Any Martians there would certainly head south for the winter!). |
Believe it or not, the engineers and scientists who designed the probe took this into account. The probe is indeed solar-powered; at its current latitude, the panels will produce about a kilowatt-hour per sol
(Martian "day"), if I'm remembering correctly from last night's coverage. (A quick Google search isn't turning up the exact figure.)
The probe is not intended to work through the entire winter.
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chemoleo
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THat's a fascinating picture! Here's a high resolution pic taken from a perspective.
http://phoenix.lpl.arizona.edu/images/gallery/lg_41.jpg
Resolution: 15m per pixel
The crater is 35 km wide and 2 km deep (!)
What I'm surprised about is that they so clearly and casually state it is water ice - I always thought the big debate was whether surface ice existed?
See this, H2O as seen from the north pole, detected by gammarays:
If there's one crater with ice, there must be many - why can't they land somewhere where there is a huge patch of surface ice?
Btw here's the relation of the landing to other previous probes:
[Edited on 26-5-2008 by chemoleo]
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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JustMe
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The MRO (HiRise) orbiter (I know, redundant) managed to get this picture of the Phoenix hanging from its parachute during descent! Amazing!
http://phoenix.lpl.arizona.edu/05_26_pr.php
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woelen
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JustMe, that is one of the best pics I have seen so far. This really is amazing! Human activity on another planet, which can be seen as real, not some
sci-fi thing!
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Sauron
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One of my old gang, Dr.Edward C.Ezell, now deceased, used to be the official NASA historian at the Johnson Space Center before he moved on to be
curator of the Department of Military History and National Firearms Collection at the Smithsonian (Natl Museum of American History).
I am sorry Ed didn't live to see this.
He was editor of SMALL ARMS OF THE WORLS, the standard reference bible in its field; author of SMALL ARMS TODAY, THE GREAT RIFLE CONTROVERSY (which
was his doctoral dissertation), THE BLACK RIFLE (with Blake Stevens), THE AK47 STORY, and more. For a while he had been Interarms man in Singapore.
I miss him a lot.
[Edited on 28-5-2008 by Sauron]
Sic gorgeamus a los subjectatus nunc.
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Rosco Bodine
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water ice on Mars confirmed by Phoenix
http://phoenix.lpl.arizona.edu/06_20_pr.php
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Mr. Wizard
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That's amazing.. Is the reddish tinge on the right hand side of the shadows in the hole an artifact or real? It sure looks like ice, especially on the
left side where it transitions to soil.
Watching a man step onto the surface of the moon again , or land on Mars would be very good too. What an accomplishment.
Sauron, did your friend help in looking for the missing moon shot film that showed the first moon landing, but are now missing or lost?
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Rosco Bodine
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The red tinged shadow edges are probably an imaging artifact
or a shadow edge coloration from the red skylight, I'm not certain.
Anyway it appears they have found half the makings for a pot of tea there,
so the British interest should be at least fifty per cent in this off world discovery
http://www.youtube.com/watch?v=wBzeR0uFHaY&feature=relat...
[Edited on 20-6-2008 by Rosco Bodine]
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MagicJigPipe
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What does that video have to do with anything?
I mean, she's pretty, but just a little big-boned 
IMO, I think it would be more worth everyone's time and money to look for valuable minerals on Mars instead of life. Water is valuable outside of
Earth. But now what?
We should be looking for sources of Pt, Pd, Au, Cu, Ni etc. so someday it will be profitable to mine these elements in space. All it will take for
space exploration to explode is for it to be profitable. I think if we found a good chunk of Pt or Au it would most certainly be economically viable
to invest in the technology needed for space-mining missions.
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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