How to Navigate a Spacecraft to Mars

EccentricAnomaly writes "JPL has an article on how to design trajectories to Mars with the porkchop plot. They use an interesting analogy between reading these plots and divining the future from animal entrails. JPL also has the most excellent Basics of Spaceflight, which is an easy to understand tutorial on how to explore deep space."

Comments

Martians...

[Mr.E (Not a pun)]

I'm from Mars.

Re:Martians...

[cmdr_shithead]

Eat shit. I'm from Dallas.

Re:Martians...

[Anonymous Coward]

And that didn't help anyone

Re:Martians...

[cmdr_shithead]

Do I have to help you, buttface?

F1r5t P1z05t!

[Trollificus]

Yeah, let's all hop in our billion dollar space ships and put this tutorial to good use.
You're a fucking retard, you fat sack of shit.

The Red Planet

[Anonymous Coward]

Here are some recent photos of The Red Planet

Re:The Red Planet

[Trollificus]

Man, you had your camera pointed the wrong way.
On the bright side though, it looks like you're one of the lucky few to capture a black hole.

Not to mention the new Sevendust album fucking rocks.

Hello

[cmdr_shithead]

This post is the first one. Also, I like cheese. I have a hat that looks like Abraham Lincoln. Please pay me now, I'm hungry. Do you want to take this outside? Huh? I have your first post HERE IN MY PANTS!!! Die /.

Hemos!

[cmdr_shithead]

When are you going to give me my dildo back?? Suck my micropenis.

9th post

[Anonymous Coward]

You all know who this post is for, don't ya!

Re:9th post

[crossbow_of_speed]

!ay t'nod ,rof si tsop siht ohw wonk lla uoY

Step one of plotting a trajectory to Mars

[kfg]

Make sure everyone is using the SAME friggin' system of units.

KFG

Re:Step one of plotting a trajectory to Mars

[cmdr_shithead]

Kiss Festering Gonads.

Re:Step one of plotting a trajectory to Mars

[npietraniec]

You sir, took the words right out of my mouth.

goatus postus

[cmdr_shithead]

roughly translated from the Latin, this means SUCK MY DICK.

Meat Muppets

[satanami69]

Well, I guess it'd put a different spin on pigs in space.

Re:Meat Muppets

[cmdr_shithead]

Hello. Please suck onto my micropenis. Thanks.

Quot at the botton of the page becauwe I am drukn!

[Trollificus]

"Since a politician never believes what he says, he is surprised when the interns will swallow the entire load without spilling a drop. Real fucking pros. -- Charles DeGaulle (aka Sevendust's new album fucking kicks ass)"

Ah, I see. . .

[kfg]

the "rocket scientists" are out in force tonight.

KFG

Re:Ah, I see. . .

[Trollificus]

S'cuse me, would you be so kind as to light my cross on your way out?

Re:Ah, I see. . .

[cmdr_shithead]

I have your rocket science ...

... HERE IN MY PANTS!! Also, eat my shit.

Re:Quot at the botton of the page becauwe I am dru

[cmdr_shithead]

I like cheese.

Oh no!

[snake_dad]

You know that the best vacation destinations always lose their attraction when people start publishing travelguides and maps and stuff... :-/

Re:Oh no!

[Trollificus]

Then I guess our trip to Alaska is out of the question?

HEY

[cmdr_shithead]

I bought a travel guide to your ASS for 5 CENTS from your MOM because I like to stay ON THE BEATEN PATH! EAT SHIT!

Poot!

[crossbow_of_speed]

[nt]

Wanderlust

[DivineOb]

It`s not the end
Not the kingdom come
It is the journey that matters, the distant wanderer
Call of the wild
In me forever and ever and ever forever
Wanderlust

Nightwish owns your sorry, nigger hating ass...

Basics of Space Flight [Hollywood version]

[Anonymous Coward]

• You need continuous thrust. Relying on Newton's 1st law to travel is for losers.
  
• Always point toward your goal. Don't do a 180 and decelerate with your main engine, no need to match speeds.
  
• Asteroid fields should look as dense as a forest, even if in reality asteroids rarely come within a mile of each other.
  
• Shadows in space aren't totally black, because then we can't see.
  
• Show stars through windows of well-lit spaceship rooms, because they're cool.
  
• A gravity assist with the Sun will help you fly much faster.
  
• Crescents of close bodies don't need to be oriented in the same way (oops, slashdot space logo?)
  

Re:Basics of Space Flight [Hollywood version]

[cmdr_shithead]

(goat (post))

Re:Basics of Space Flight [Hollywood version]

[DNS-and-BIND]

Don't forget:

• All objects in space make whooshing sounds or deep, rumbling sounds as they pass by.

Stephen King, author, dead at age 54

[Anonymous Coward]

I just heard sad news on talk radio - Horror/fiction writer Stephen King was found dead in his Maine house this morning. I'm sure we'll all miss him - even if you didn't read his books you've probably enjoyed one of his movies. Truly an American icon.

Re:Stephen King, author, dead at age 54

[Talez]

And in other news... Cesium(sp?) created by those guys at MIT was just released... Can you at least find supporting evidence (and no, those crackpots that whinge on talkback radio arent evidence) before you post something so final.

Talez

EXPLORE THIS FUKKAZ

[Anonymous Coward]

nude teen sex pics pubeless teen pussy amateur teens xxx-treme group sex virgin teensex oriental teensex lesbians and dildosex asianpornstars teen sex and blowjobs transexualdreams tittyfucks whoring teen amateurs amateur teen ass amateur teen lesbians interracially teensex skinny teens teen blow teen cum andi hairless teen crotches hot college teen pussy playful teen pussy sweet teen pie sexy young teens tender and tight young and sweet teen boobies teenie sex babes little teen lesbos little teen slutties amazing teen pussy hairy latina pussy alisons bald cunt annies shaved pussy brookes pubeless pussy sweet sexy blonde teens demi cynthia flaming red pussies brown haired babes wet brown pussy teen cum licking whores cum squirts busty blonde ladies black booty cuties black blowjob babes ebony labia lickers ebony blows asian fucked asian lesbians asian ladies big titted asians asian nurses asian virgin teens amateur asian teens bad asian teens sexy young asians tender asian teens vietnamese teens young asian cuties hardcore oriental teen sex asian teen panties japanese teen pussy cock suckin teens puffy teen pussy soapy teen titties tanlined teens brown teen pussy big titted red head play ground teens red headed cheerleader cheerleading pussy bad girl abby dark teen stockings masturbating teen. sexy teen cunt flat chested blonde teen teen in white panties big tits furry pussy pussy cheers lusty teen lesbians gaping teen hole spread teen pussy teen facials black bitch white cock blonde teen blowjobs muff munchers teen penis puffers asian american lesbians asian blonde teen lesbians asian teen lesbians blonde teen group lesbiansex masturbating lesbian teens teen lesbian sluts deep throat teens splooge teens teen cock sucking cunts teens and dildos cum fucking sluts asian teen pussy nude asian teen ass asian bondage teens asiantits - big & tiny not so innocent asian teens hot korean twat sweet asian pussy hairy asian pussy asian ass teen fux fucking cunts bitchin sex slut fuckin hardcore penetration penetrating fucks group penetration shut up and suck bitch group sex xxx more than 1 is fun blow bitches cock whores pussy whores vagina sluts teen pussy sluts lesbo teen sluts mom and friends mom gets laid mommy sucks cock cheerleading teen ass cindys teen cunt hot teen pussy hot teen slits sweet teen pussy brittanys nude cunt latina sluts sweet teen sluts teen latina cunts sexy latina teen pussy lacy latina latina ass big black boobies hot black ass masturbation shower black teen honey blonde lesbian teens blonde teen cutie cute pussy lesbian coochie lesbian house maids lesbian trio pink lesbian pussy sex on the bitch white stocking blondes asian dildo fuck and suck bald college pussy bathing suit sweetie black lingerie caramel lesbian love dark fantasy flashing mothers floppy titties loose asian pussy my sister amber nude wild latina pussy all american amateur teens black and shaved jap teensex latina hump sluts my neighbors wife oily asian teensex pink teen nipples red heads teen boobies shaved white teens skinny amateur teens tan blonde titties thick amateur slut tiny thin teen tits tiny white teen tits white teen slut white teen tits and pussy asian teen xxx asian bondage big tits and teens big titted teensex sex party hot sluts lingerie and blowjobs adoring lesbian lovers group fucks double fuck suck hardcore sex sluts anal intrusions anal sex sluts pregnant bitches lesbians latinas anal invasion hit that ass all sex cock suckin whores classic pix blow hards copulating couples cum shots hard fucks hole in one sex sex sex sex sluts muff muff oriental fuckfest lesbos muff luvin girl girl asians undressed black pussy black ass teens big tits redheads rose anna amateur fuck suck parent teacher teacher sex black white teens sweet teens school blows bondage hardcore teen ass slutty slitties titty sex

Re:EXPLORE THIS FUKKAZ

[cmdr_shithead]

goat?

Let me get this straight...

[Anonymous Coward]

The worst terrorist attack in recorded history occurred in September, and now we
're involved in a WAR against Islam and you people have the gall to be discussing navigation to Mars???? My *god*, people, GET SOME PRIORITIES!

The bodies of the thousands of innocent civilians who died (and will die) in these unprecedented events could give a good god damn about navigating to Mars (but admittedly, many might find it cool), your childish Lego models, your nerf toy guns and whining about the lack of a "fun" workplace, your Everquest/Diablo/D&D fixation, the latest Cowboy Bebop rerun, or any of the other ways you are "getting on with your life" (here's a hint: watching Cowboy Bebop in your jammies and eating a bowl of Shreddies is *not* "getting on with your life"). The souls of the victims are watching in horror as you people squander your finite, precious time on this earth playing video games!

You people disgust me!

Re:Let me get this straight...

[crossbow_of_speed]

Poot!

Re:Let me get this straight...

[MADCOWbeserk]

Easy tiger,

I'll get you your gun and send you over. Some need to remain behind, and live those lives the terrorists hate so much.

Mars sounds like a good idea, my guess is that it will be hard to get to Mars with an expired student visa.

Re:Let me get this straight...

[Hektor_Troy]

good - a job well done.

Re:Let me get this straight...

[Lars T.]

You want to talk war, and ignore the god of war, Mars? No wonder you're not getting anywhere.

I am CHEESE!

[cmdr_shithead]

JPL has an article on how to design trajectories to Mars with the porkchop plot . They use an interesting analogy between reading these plots and divining the future from animal entrails. JPL also has the most excellent Basics of Spaceflight, which is an easy to understand tutorial on how to explore deep space.

JPL has an article on how to design trajectories to Mars with the porkchop plot . They use an interesting analogy between reading these plots and divining the future from animal entrails. JPL also has the most excellent Basics of Spaceflight, which is an easy to understand tutorial on how to explore deep space.

JPL has an article on how to design trajectories to Mars with the porkchop plot . They use an interesting analogy between reading these plots and divining the future from animal entrails. JPL also has the most excellent Basics of Spaceflight, which is an easy to understand tutorial on how to explore deep space.

• JPL has an article on how to design trajectories to Mars with the porkchop plot . They use an interesting analogy between reading these plots and divining the future from animal entrails. JPL also has the most excellent Basics of Spaceflight, which is an easy to understand tutorial on how to explore deep space.

eat shit slashdot.

goat

[cmdr_shithead]

<TT>goat goat</TT>

fp!

[Anonymous Coward]

First Penis!

8====D
Boiiinng!

gravity assist finally explained

[Gunstick]

This is the best explanation of swingby manoever or gravity assist I have seen.
And generally well done.

Re:gravity assist finally explained

[esonik]

While the "Basics of Spaceflight" page is really nice, the "porkchop" page is quite lame - it wastes 5 pages to convince people that porkchop plots are nice and important tools, but when they show one of the plots on page 2 (!) they don't even explain what one can see there. So I'll try to do it myself:

• The plot is for the two 2005 Earth-to-Mars transfer opportunities, using ballistic transfer (i.e. no propulsion during the flight except for orbital departure/insertion)
  
• The horizontal axis is obviously the launch time from Earth, while the vertical axis is arrival time on Mars.
  
• The two possible "windows" to Mars for 2005 seem to be the centers of the two blue coutour plots (if we only knew what the blue "C3L" lines mean!).
  
• The red lines seem to be lines of constant travel time (labelled "TTIME"), so the lower window is for the shorter route (200 days TTIME as opposed to 400 days TTIME).
  

The remaining questions are: What are the blue lines ? (very essential as they define the "windows". Maybe arrival velocity?) What are the magenta and green lines ?

Re:gravity assist finally explained

[Parys]

> if we only knew what the blue "C3L" lines mean!

C3L is the specific energy needed at launch to enter the transfer orbit from earth orbit. It's the square of the delta-V, I believe, and its a common number used to select a launch vehicle. Given a certain mass that you want to insert into Mars orbit, a Delta rocket, for example, would only provide a certain amount of C3, and if that isn't sufficient according to the porkchop plots, it's a no-go.

The reason you have two local minimums on the plot is because one set is for a Type I orbit, traveling less than 180 degrees in the transfer orbit, and a Type II, traveling between 180 and 360 degrees.

Re:gravity assist finally explained

[Parys]

OK, another reply to same parent. This page gives a pretty good explanation of the equations and calculations for the hyperbolic escape orbit.

Was that /.'s Metatag?

[MADCOWbeserk]

Now I know how /. gets so many hits... <BR> <BR>Hey Coward, save the stupid stuff for the NYT's forum. <BR>

really?

[Nevrar]

bah... all you need is a computer called HAL - he does it all for you :)

Sounds like software development to me

[ColaMan]

Let's look at the similarities ...

It costs a shitload.

You normally have a few earlier versions that didn't perform to plan.

You need to aim at a moving target that won't be there for two years, and of course you're own platform is moving as well.

Not forgetting that if you're careless and not do your sums right , you'll crash and burn spectacularly and look like an idiot in front of the rest of the world.

The major difference is of course (drumroll , please)

In Space, no-one can hear your FUD.

Piiiiiiiigs iiiiiiiinnn spaaaccce

[ZaneMcAuley]

Set pork chops to stun

Ah, time, time...

[imipak]

It's a funny thing, I wget'ed (wgot?) that tutorial months ago... "Aha! At last a way to wile away the long gaps between new issues of TVGoHome - I'll teach myself orbital mechanics! And there it sits, unread, along with everything else I mirrored for offline reading... unread whilst I just check Slashdot one more time... (Those links probably won't work unless I'm online. Goddam these UK phone charges... )

Deep Space Tutorial

[zdzichu]

>"which is an easy to understand tutorial on how to
>explore deep space."

every scout's need?

Rocket Scientists

[Alien54]

Since we're going to start having amatuer rocket scientists traveling into space ...

It looks like JPL is helping people figure out how to get to mars on thier own. Tragically, I can see the fruit cakes now.

I imagine it won't be so bad, so long as they leave a trail of bread crumbs,p.;-)

Brave man...

[No Such Agency]

Not only did you link to your home box on Slashdot (as we know, infamous for bringing even the largest websites to their knees), but now everybody knows your IP address too. That takes guts. Of course, if you're not online all the time, you'll be of much less interest to jerkwad scr1pt k1dd13z who want to run their personal pr0n site off your HD... Cheers!

Re:Brave man...

[imipak]

heh! I didn't think of that... but, just to compound the risk - I'm pretty confident my properly secured NT4 box can take the heat. No, really, I am! OK, admittedly, I'm running low on medication, but still...

Re:Brave man...

[imipak]

Wow, lotsa hits in fact... I'm surprised!

andrew@INEGO% tail -100 access_log |grep -v
192.168.0|awk '{print $1}'|sort|uniq
127.0.0.1
130.215.233.215
160.36.81.191
192.156.13.35
192.156.13.36
213.89.4.32
216.165.42.86
216.170.210.56
61.136.15.233

And anyway, skipt |1dd135?? On Slashdot??? Surely not...

Manned by mice?

[Anonymous Coward]

I wonder if this mission will be manned by mice?

Some more...

[Anonymous Coward]

Always show stars whizzing by the windows, even if you are going at slow speeds in a straight line [Galactica Vipers]

If you are out in zero pressure, you will scream and your eyes will look like those of cartoon characters [Total Recall]

If you want, open up the hatch on your spaceship, pop your head out, and get some fresh air [Message from Space]

Mmmm ....

[gcondon]

Pork Chops!

RE: Earlier post.

[fshalor]

And this follows nasa releasing this stuff s little while ago. Are these guys (JPL and NASA) trying to get us to do their jobs for them? (By what else...sending pigs to mars! Pun intended.) Or is this just them clearing out old stuff to make way for new stuff. My bet is their magnetic tape media is getting unstable and they're too ashamed to admit it. Their sending it out to the world to let us mirror is in lots of places, under the allusion that it's actually worth something. It would be interesting though, to spend some time checking through these programs and tutorials to see if problems which led to the Challanger disater are apparent. Freynman said that the software development at JPL and NASA was tops, but he was comparing it to other parts of the organizations which were using orings for expansion joints which were designed as compression fittings. And other such problems. -=fshalor

Use Castors!

[JabberWokky]

I've always found that having a genius level set of twins, a cantankerous grandmother who writes Space Opera and a beset upon set of parents trying to raise a young child is a great way to get to mars. Sure, the bikes won't turn a profit post-tariff, but the flatcats will make serious money out in the belt.

Failing that, just standing on the ground and looking up and wishing really hard sometimes works. You get scantily clad Martian princeses that way, too!

--
Evan "going through and rereading all his Trek novels, but may take a Barsoomian vacation for a bit" E.

Orbiter Simulator.

[Anonymous Coward]

There's a great space-dynamics simulator called Orbiter.

You can really get the feel for what's involved in plotting trajectories and getting to the right orbit. It's really good.

And, it's free! (beer)

Stone family

[rossdee]

IIRC they used Hazel's figures, as hers were the median...

Would have been interesting if they had used Meade's...

Re:Stone family

[JabberWokky]

Bless you... I've been making classic SF references (hint: I don't consider "Star Wars" classic SF) for a long long time on Slashdot - it used to be recognized and replied to way back when (before the great user purge), but hasn't in *years*.

Ah, the glories of riding up on a tower of flame from your backyard, slipstick in one hand, the future ahead. It's a damn shame that we socialized space. It'll be there, though... it's been waiting for quite awhile.

--
Evan "Ad Astra Nauseum... but the Eagle has landed, tell your children when; Time won't drive us down to dust again" E.

Can you identify the variables?

[ChrisCampbell47]

On the porkchop plot, according to the legend at the top, the various curves are plots of the variables:

• C3L
• TTIME
• SEP
• Ls

Can anyone tell us what those mean? Even just a few words that we can then go google. The body of the article mentioned a few things (like time-of-day orbital plane at Mars) but didn't explicitly correlate those ideas to the variable names.

Re:Can you identify the variables?

[EccentricAnomaly]

C3L = C3 of Launch... C3 is (2*(Kinetic_energy/mass))^2 (or if you know orbit mechanics V-Infinity^2)

TTIME = Transfer Time (days)... that is, how long it take to get to Mars

SEP = Sun-Earth-Probe angle... that is, the angle on the corner of the triangle made by Sun-Earth-Probe... when this angle is too small you can't get a signal from the probe because of the noise from the Sun

Ls --- I'm not sure on this one, it seems to be some sort of Launch angle

Re:Can you identify the variables?

[ChrisCampbell47]

[other variables]

Perfect! Thanks!

Ls --- I'm not sure on this one, it seems to be some sort of Launch angle

OK, with that hint I was able to figure it out. It's Earth-Sun-Mars angle, or, effectively, how far Mars is from Earth:

1. Using a solar system simulator, I find that there is a Mars/Earth conjuction around 05-Nov-2005 (hmmm, 4 years from today) and around 25-Dec-2007 (hmmm, Christmas) -- those two dates are 2 years and 50 days apart, or 780 days.
2. During that period, these two planets will swing through 360 degrees of Earth-Sun-Mars angle.
3. Or, 180 degrees takes 390 days.
4. Now, looking at the plot, the 0 Ls mark is at about 22-Jan-2006, and the 180 Ls mark is at about 10-Feb-2007. That's 384 days.

Off by 1.5% just taking a guess and eyeballing the chart. Sounds like a confirmation to me :)

Right?