NASA Phoenix Mission Ready For Mars Landing 101
Several readers relayed the press release from JPL about the upcoming landing of NASA's Phoenix Mars Lander on May 25. It's going to set down in the north polar regions and look for indications of whether conditions have ever been favorable for microbial life. "Phoenix will enter the top of the Martian atmosphere at almost 21,000 kilometers per hour... In seven minutes, the spacecraft must complete a challenging sequence of events to slow to about 8 kilometers per hour... before its three legs reach the ground. Confirmation of the landing could come as early as 7:53 p.m. EDT. 'This is not a trip to grandma's house. Putting a spacecraft safely on Mars is hard and risky,' said Ed Weiler, associate administrator for NASA's Science Mission Directorate. 'Internationally, fewer than half the attempts have succeeded.'"
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Re:Great stuff I guess but why isn't NASA doing mo (Score:2)
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Don't say
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But then I guess most partys and leaders and such gets their share of bashing no matter who they are, and Bush may be a moron extraordinaire so I guess it's appropriate and understandable.
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LEO - Low Earth Orbit
But then I found MSL, "lunar pie-in-the-sky" and MER.
What does it all mean?
IANAAS.
Good article and GREAT PICTURES of the Phoenix (Score:5, Informative)
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Re:Good article and GREAT PICTURES of the Phoenix (Score:5, Funny)
Re:Good article and GREAT PICTURES of the Phoenix (Score:5, Funny)
"The lander exploded in, according to latest estimations, about 13,000 pieces. As you may see in this depiction, some of those pieces may hit opportunity and start a chain reaction of exploding landers."
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The Mars Scorecard [anl.gov].
Mars currently leads, 20:19, though Earth is making a strong showing this decade.
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Trips to grandMars' house (Score:5, Funny)
NASA: Oh my, Mars, what big craters you have!
GrandMars: All the better to SWALLOW you with.. grrrr!
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when a shiny red planet came my way.
It was big and looked rather hard,
would my chute and jets help me retard?
To see if I could find life in the icy clay?
Good luck Pheonix
Mod parent up (Score:1)
Slow to about 8 kilometers per hour. (Score:2, Interesting)
In seven minutes, the spacecraft must complete a challenging sequence of events to slow to about 8 kilometers per hour...
Why reducing the box? Is there any reason to discard a higher speed landing?
What if they find a way of slowing down to 16kmh, they abandon the mission?
I'm not talking about considering compressing time continuum to extend those 7 minutes, but it seems there are possibilities that could still be considered, like hardening the legs, finding a softer spot to land, finding a lower landing spot to extend braking time, etc.
Re:Slow to about 8 kilometers per hour. (Score:5, Interesting)
Plus, it has to land under autonomous control, so you really have no idea how fast it actually landed or exactly where until several minutes after it has landed - so coming in a little too fast isn't a good option, neither is a stray patch of rock (there are few "soft spots" on Mars, by the way - it's mostly rock). Much better to land as gently as you can manage and do your braking manoevures in the "air" as you come down. You've got plenty of time, the physics are easier to calculate, and there's less to go wrong.
The first few hours of a new lander's life on another planet are basically checking that everything still works, even with all the gentle landings in the world, things get broken that cost MILLIONS to put them up there. 50% of the things still never make it to the planet operational, even with all the good will in the world behind it. You want to spend MULTIPLES of the cost of the entire project on making the landings more difficult, more violent and less reliable when we can't even get half of what we send onto the planet successfully?
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Because even at 8km/h you can do serious damage.
You could replace 8km/h for 4km/h in your entire reasoning and it would still stand, yet neither would address my point.
I do understand that 8km/h is not an arbitrary limit. However, stating the landing problem as "There is only one chance! They absolutely must do this or everything will fail!" seems much more oriented to make the news more exciting than because of 8km/h being the perfect speed to put the lander on Mars.
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8 km/h is the target touchdown velocity. They'll come pretty close, probably with a couple km/h of that speed, but it pr
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treble (trb'l) adj. meaning Triple
Perfectly valid English in every English dialect and has been for hundreds of years (Answers.com actually pointed me at a George Eliot quote as an example of its use). Treble sounds better in a sentence such as that one (it matches better with "double" than triple would and feels more natural for most native English-speakers) and there are certain places where we British prefer treble to tr
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to treble (third-person singular simple present trebles, present participle trebling, simple past and past participle trebled)
1. (transitive) To multiply by three; to make into three parts, layers, or thrice the amount.
2. (intransitive) To make a shrill or high-pitched noise.
3. (intransitive) To become multiplied by three or increased threefold.
From: http://en.wiktionary.org/wiki/treble [wiktionary.org]
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He must work for the government then...
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"the spacecraft must complete a challenging sequence of events"? Come on.
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Maybe that's where the name idea came from...
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not wanting to be harsh, but it doesn't sound like you've thought it through too much. try running your car into something at 16km/hr and get back to me.
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not wanting to be harsh, but it doesn't sound like you've thought it through too much. try running your car into something at 16km/hr and get back to me.
So, your way of studying the landing speed limit of an object in another planet is crashing you car into objects.
Well, now that you started with the ad hominem, let me do a follow up.
Obviously just about everyone who reads this news understands the implications of a landing at 16km/h. Please make an effort to avoid thinking anyone might be under your intellectual level; you'll fail more often than not on that one.
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Well, it seems to work for particle physicists...
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The speed will not be twice what the spacecraft can withstand... for a good reason: They run simulations with varying entry angles, entry speeds, wind speeds, etc... to figure out the highest landing speed possible, and design for that.
There is no need to harden anything if the design is soun
whose grandma ? (Score:5, Funny)
You've never met my grandma. As a kid, going there felt like a 25,000 mph trip, and there are still skidmarks from my shoes trying wildy to decelerate while my parents dragged me into the house. And about half of the times they tried taking me there, it failed too...
Re:whose grandma ? (Score:4, Funny)
Re:whose grandma ? (Score:5, Funny)
fewer than half? (Score:1)
this guy makes it sounds like more than just a handful, and I can only recall 3.
is there some vast international mars landing conspiracy that i'm unaware of?
Re:fewer than half? (Score:5, Informative)
Yes. The details are hidden away on wikipedia where you'll never find them! Some details:
Mars 2 (1971): Landed but lost contact within minutes
Mars 3 (1971): Same
Viking 1 (1974): Landed and remained operational for 6 years
Viking 2 (1974): Landed and remained operational for 3 years
Phobos 1 (1988): Lost on the way to Mars
Phobos 2 (1988): Got into orbit, took some photos, then failed
The more recent ones you probably know about. To be fair, the Phobos 1 and 2 missions were planning to land on Phobos, not Mars, so maybe they don't count.
Don't Forget the Space Race! (Score:3, Informative)
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I count only three non-American Mars landing missions, too: Russian M-71 and M-73, and Europe's Beagle 2 on Mars Express. But perhaps he was referring to the numerous international Mars orbit and flyby missions which have also failed.
See Astronautix.com [astronautix.com] for details.
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Quite a few included rovers/landers in one sort of another, and many failed. The first attempt was a Soviet probe in 1962, it didn't even leave Earth orbit properly, but it was a planned mission.
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#space on irc.freenode.net Phoenix Landing Party (Score:5, Informative)
Re:#space on irc.freenode.net Phoenix Landing Part (Score:2)
Come by for a visit folks and help us celebrate the landing, you won't be disappointed.
This is not a trip to grandma's house (Score:1, Funny)
Re: Hard and Risky??? (Score:5, Funny)
They're just learning from past mistakes.
Much like the experienced worker that estimates a month for a two hour job.
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I work in a factory, and the first time that someone uses something like a table saw, they are nervous. I is a dangerous tool and could seriously injure them if they are not careful. But most of the injuries I see cause by power tools are by people who have gotten too comfortable with them and have forgotten about the risk involved.
commonplace != safe and easy
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Safety is built on putting together good procedures that you follow every time. It is only when you get careless and remove these procedures that people get hurt... Countless industrial and aircraft accidents back this up...
This is also the reason why flying is safer than it used to be, I might add... Meaning, checklists and safety procedures is what makes things reliable and safe to use...
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Paid quite well? JPL pays slightly under industry wages, but it IS a nice place to work, and glamorous. NASA pays substantially lower (government civil service jobs.. but there are some intangible benefits that are hard to quantify, and some t
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I am not saying the job is easy, but many jobs are not. With the amount of money at stake on each mission, however, failures must to be rare, and not part of doing business. The groups in the 1960's understood this, and it is not because they had mo
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All I am saying is I am having a hard time seeing why it is so much harder than it was in the 1970's when they landed the Viking missions, and it was the first time they ever touched down on the planet. Also, did I mention that both missions were successful...
If "success" is defined as "slam something, anything, into the ground somewhere, somehow, that can still send a couple pictures back afterwards". Sure. Phoenix, of course, weighs an order of magnitude more, has to hit a landing spot chosen from science reasons (and not for "make it easy on the lander" reasons) and carries sensitive scientific instrumentation that still has to be able to do quantitative chemistry analytical work after the landing.
...and suddenly the whole thing becomes a whole lot harder
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Re: Hard and Risky??? (Score:5, Insightful)
Cut them some slack! Most of us slashdot readers have trouble getting an Apache install right the first time through. These guys are doing nearly the impossible and they don't get much of a chance to fix any mistakes.
There are like THOUSANDS of possible things that could go wrong with the landing that DON'T because the engineers did their job. If you have ever engineered anything, you know how much you have to think ahead. They sat really hard and long and tried to perfect the landing process.
But it's darned hard. Mars is really really really far away. The data transfer speed to the lander is like 16KB/s on a good day. You can't send realtime flight data and have a pilot fly the thing with a joystick (because of the latency and the bandwidth is just too limited). You just have to build smart control logic into the thing and hope for the best.
And -- what can ruin the whole thins is -- just one largish rock in the wrong place and the whole mission is a failure. Historically, only 5 out of 13 landers made it to the surface operational!
So, stop being a douche and start appreciating how hard this all is. And it isn't just NASA -- the Brits also tried and failed. It's hard. NASA is doing a great job. Let's see you send 100LBS of spacecraft millions of miles away and have it get there safely. It's pretty amazing it ever worked at all!
Oh and what "corporate committes"? Last I checked NASA was a government agency.
Stop thinking like a corporate douch and start thinking like a scientist. These guys are smarter than you or I and give them some respect.
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There is little that can be done about this practically. It's just they hope it won't happen. They chose a landing site that has few if any large rocks, and they are just hoping for the best -- but there still is a nonzero probability they w
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In short, scientists study, but all engineers are very comfortable with the idea of managed risk. It is pa
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Yes, there is more than one way to land on Mars. But those other ways cost more money. The Phoenix project wasn't designed from scratch; it was a reasonably cheap way to get some use out of the aborted Polar Lander hardware, which otherwise would have gone to waste. So they designed it as cheaply as possible consistent with a reasonably good chance of surviving the landing. If it works, great. If not, the hardware wa
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Yea, we should have this Alaskan crab fishing thing down pa
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Meaning, no job is just accepted to be risky by nature, because there really is no reason for it. As OSHA has shown time and time again, safety is always built on the procedures put in place that you follow every-time. It is these procedures that keep people safe. It is only when people get lazy, and stop follo
Argh! units units units! (Score:4, Funny)
I'm sure you have, but you know, we've been here before...
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Very good strategy on behalf of NASA, I'd say.
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In a heliocentric, sun-fixed coordinate system, the Earth (and thus the LOC) move at about 30km/s which comes to about 108000 km/h - about 5 times faster than the Phoenix lander.
Then again, nobody is trying to land the thing on Mars.
Slow transfer rate to Mars (Score:5, Interesting)
Wow, that isn't a fast transfer rate. That's about 1KB/s, 4KB/s, and 16KB/s, respectively. I guess you don't need too much more -- but still, I bet it's slower than they would like. The high resolution camera alone probably produces images that are a few megabytes in size. Let's say the images are like 4MB -- Transferring 4 MB at 1KB/s takes about an hour!
Given the slow xfer speeds and limited hardware they probably use -- I think it would be fun to be a programmer for NASA. That's one of the few applications where efficiency of communications, small memory footprint and efficient CPU usage probably still count for something.. I bet you everything they do when it comes to the software running on the lander tries to be as efficient as possible (especially communications-wise).
Also, isn't there something like an few minutes of latency for light to reach us from Mars? You can't even really do any really realtime interaction with the onboard computer on the Phoenix lander.. Imagine typing into a shell and waiting a minute for your characters to appear! Ouch! So I bet you they have to premeditate a lot of the changes they make to the software or operating environment way a head of time -- they probably just upload scripts of commands when updating the software or filesystem, etc.
I wonder how much freedom they give the people communicating with the lander. Do they triple-check every command sent to it to make sure noone does the inadvertent 'rm -fr
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Actually, this was happening quite frequently back in the dial-up days.
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This happened all the time back in '83 and '84 on a VAX 11/780 at UCSC. Come the end of the quarter, the VAXen would all be overloaded (we're talking load averages over 30, with spikes up to 70).
You'd type a command, go away and get a cup of coffee, and maybe when you got back, you'd get an acknowledgement that you actually did something.
However, in tribute to the 4.2BSD guys (original Berkeley, not Open/Net/FreeBSD), even with this insane overload, the VAX... Did... Not... Crash.
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I wonder how much freedom they give the people communicating with the lander. Do they triple-check every command sent to it to make sure noone does the inadvertent 'rm -fr /'?
Actually they've messed up a satellite this way. A detaild explanation can be found here [nasa.gov], quote "A modification to a spacecraft parameter, intended to update the High Gain Antenna's (HGA) pointing direction used for contingency operations, was mistakenly written to the incorrect spacecraft memory address in June 2006. The incorrect memory load resulted in the following unintended actions ...". It's actually pretty amazing that they've managed to reconstruct the whole sequence of events, most likely by usin
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Typing into a shell is not only slow but far to risky. Everything gets tested fo
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Several readers (Score:1, Offtopic)
Umbrella Corporation (Score:1, Offtopic)
Martian Scorecard: 50% (Score:5, Informative)
half as many (Score:3, Insightful)