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New Kind of Orbit Could Ease Mars Communications

kdawson posted more than 4 years ago | from the crossing-gravitational-gradients dept.

Communications 127

japan_dan writes "An interesting way to enable Earth-Mars communication when the Sun occludes the direct radio line-of-sight: ESA proposes placing a pair of continuous-thrusting relay satellites, using a solar electric propulsion system — one in front and ahead of Mars, the other behind and below — with both following non-Keplerian, so-called 'B-orbits'. This means the direction of thrust is perpendicular to the satellites' direction of flight, allowing them to 'hover' with both Earth and Mars in view. Quoting from the Q&A: 'We found that a pair of relay satellites would only have to switch on their thrusters for about 90 days out of every 2.13-year period, and this solution would only increase the one-way signal travel time by one minute, so it could be effective.'" Here is the paper describing non-Keplerian orbits (PDF).

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That's good news (4, Funny)

Lord Lode (1290856) | more than 4 years ago | (#29768887)

That's good news for the diplomatic Human / Martian relations.

Re:That's good news (1, Funny)

Chris Burke (6130) | more than 4 years ago | (#29768919)

You'd think, but the fools are assuming the extra minute of round-trip communication time isn't a problem because it doesn't seriously affect their reaction times. But they fail to understand that in the Martian language, time is a critical component of meaning! And extra minute of latency could make the difference between saying "We accept your offer of peaceful relations. We will begin transmitting cultural information immediately," and "We accept your offer of peaceful relations... Psych! We will begin bombarding you with Vanilla Ice CDs immediately, losers!"

Re:That's good news (1)

gnick (1211984) | more than 4 years ago | (#29769201)

I don't think that we should attempt communication communication with the martians at all until they contact us. From what I've read [wikipedia.org] , they can grok our meaning without much trouble (partially due to psychic abilities). However, their lack of adherence to our conservative moral platforms and religious dogma may doom our relations to tragic failure...

Or their aesthetic sense. (1)

zippthorne (748122) | more than 4 years ago | (#29769831)

An entire planet of nigh omnipotent interior decorators, and they chose "desolate, barren red rock..."

Re:Or their aesthetic sense. (2, Funny)

RKThoadan (89437) | more than 4 years ago | (#29769919)

They're interior decorators so it looks great on the inside. If they can meet up with a race of landscape designers everything will be beautiful.

Re:Or their aesthetic sense. (3, Funny)

jefu (53450) | more than 4 years ago | (#29770019)

Perhaps we need to arrange an introduction between the Martians and the Magratheans.

Re:That's good news (1)

dissy (172727) | more than 4 years ago | (#29770265)

But they fail to understand that in the Martian language, time is a critical component of meaning!

The only martins we are interested in speaking with are generally speaking English, Chinese, or Russian. So that will not be a concern.

Re:That's good news (0)

Anonymous Coward | more than 4 years ago | (#29770373)

NOOOOO NOT Vanilla Ice! That's against the Conscience Ratification Accord Protocols.

Late Breaking News from the Council (0)

Anonymous Coward | more than 4 years ago | (#29770437)

We accept your offer of peaceful relations... Psych! We will begin bombarding you with Vanilla Ice CDs immediately, losers!"

Correct, HALT! Collaborate and listen,
Council's back with a brand new invention,
Gelsacs, grab ahold of them tightly,
Speared with a harpoon, goo will flow rightly,
Will it ever stop? Glarg, no!
Pink things from Blue world, you just don't know,
Your robots are a problem the Council's resolvin',
VICTORY FOR MARS, 'round LaGrange you're revolvin'.

Mars, Mars, bitches, too cold. (too cold...)
Mars, Mars, bitches, too cold. (too cold...)

- K'Breel, Speaker for the Council of Elders and Rapper for the Council of Culture.

(When a junior music reporter said "I'mma let you finish, K'Breel, but you're merely riffing off an Earth song from 20 years ago, and the aerobraked packages of Vanilla Ice CDs were selling better than anything the Council of Culture had produced in all time - IN ALL TIME!", K'Breel had the reporter's gelsacs pressed into discs, vapor-deposited with a think layer aluminum, inscribed with lasers, and placed into a mass driver aimed back at the source of the original Earthican launch site.)

This differs from Earth how? (1, Funny)

Anonymous Coward | more than 4 years ago | (#29770475)

"So will you be pulling your troops out of our city?"
"..."
"Pull your troops out or we will be forced to liberate it ourselves."
"..."
"Are you looking for a fight?"
"Yes."
"You have it then! "
"Don't worry, we will have the troop out in no time"
"No certainly not, we will withdraw peaceably"
"Wait, what!?!"

Re:That's good news (1)

FlyingBishop (1293238) | more than 4 years ago | (#29769007)

Why the fuck would that be? Now we don't have to wait a few months to cool down before sending off an asinine reply to whatever stupid shit the Martians throw at us next. Now we can insult them with only a 11 minutes of lag. That can in no way be good for diplomatic relations.

You're a dumbass.

Re:That's good news (1)

mdm-adph (1030332) | more than 4 years ago | (#29769059)

Laugh, but just the fact that we're collectively trying to work out the problems of interplanetary communication now that we'll certainly have in the future (if we don't destroy ourselves) made my day.

Not really (0)

Anonymous Coward | more than 4 years ago | (#29769961)

I doubt Vilos Cohaagen would agree...

Re:That's good news (3, Funny)

mabhatter654 (561290) | more than 4 years ago | (#29770447)

As long as we don't go bombing their planet to look for water.... that's BAD for relations.

Re:That's good news (1)

maharb (1534501) | more than 4 years ago | (#29771333)

But if they have water then they could have plants which means there could be oil. The oil is worth bombing for, so the water is too, right?

lets wake up here (-1, Flamebait)

Gothmolly (148874) | more than 4 years ago | (#29768929)

Since there's barely anything useful on the Moon given the cost of getting it, and there's even LESS useful on Mars (again, considering the cost of getting it), is it time to scale back the already neutered-to-the-point-of-a-joke NASA program, and let either private enterprise (?) explore space, or forget it? If you can steal an asteroid, park it at a Lagrange point, then mine it for some super expensive unobtanium thats fine, but do we really need to keep spending money playing robots on the surface of Mars ?

Re:lets wake up here (1)

Saija (1114681) | more than 4 years ago | (#29769045)

Since there's barely anything useful on the Moon given the cost of getting it, and there's even LESS useful on Mars

Hmmm and what about the experience in design, contruction, operation and manteinance of ships, tools, environment and crews to get there?
how are we suppose to left this rock if don't start trying to get to the nearest, not so deadly rocks around here?
Egss in a basket on something like that i hear it's called...

Re:lets wake up here (0)

Anonymous Coward | more than 4 years ago | (#29769721)

Stop raping the English language, please.

Re:lets wake up here (-1, Flamebait)

Anonymous Coward | more than 4 years ago | (#29770805)

Shut up, nigger.

Re:lets wake up here (4, Funny)

fractalVisionz (989785) | more than 4 years ago | (#29769135)

and let either private enterprise (?) explore space

I agree, even 6 year-olds are doing it.

Re:lets wake up here (5, Insightful)

ElSupreme (1217088) | more than 4 years ago | (#29769183)

Yeah nothing that NASA has done has affected your life in the positive. Lets just wait for private enterprise to go there.
The only reason private enterprise is able to *think about* real space travel is because they are using the ~40 years of NASA knowledge and research.

http://science.howstuffworks.com/ten-nasa-inventions.htm [howstuffworks.com]
Ok so this is really basic, but also aerogel, and a laundry list of other things.

Being on Mars is really cool, and we have learned a lot about it. But as for usefulness it tells us maybe mining Mars wouldn't be that profitable (but did we know that before). But all the stuff they used to get to Mars, that shit trickels down FAST. I mean I personally believe that SSDs on the rovers are wat put them into the main stream. They lasted in a super harsh enviroment orders of magnitude longer than they were supposed to. So keep thinking all NASA produces is cool photos.

Re:lets wake up here (1, Insightful)

Anonymous Coward | more than 4 years ago | (#29769289)

You speak sense, but if you come to slashdot and piss on the sci-fi nerds' fantasies of colonizing the universe within the next hundred years, you're doomed to be buried in flames. Mostly what you'll see is people terribly excited about frontier-style colonization efforts or admitting that our current space efforts make little sense but justifying them because it's good practice for our engineers. It's too early for colonization (we're not even close) and the "good practice" justification is just nonsense, but for some reason those are the most popular arguments.

AC so that only one of us goes down in flames =)

Re:lets wake up here (4, Insightful)

mcgrew (92797) | more than 4 years ago | (#29769403)

What are you doing at a nerd site? Money is the LAST thing a nerd is thinking of when (s)he thinks of space. Space is for technological and scientific advancement. Sue, there will be money made in the future, but private enterprise operates on the next fiscal quarter.

NASA is doing ot because (duh) THERE'S NO MONEY IN SPACE EXPLORATION and money is the only reason for private enterprise to even exist.

Re:lets wake up here (1)

Zarf_is_with_you (1382411) | more than 4 years ago | (#29769779)


Sure there is money for Private Enterprise in space, if T-Mobile put the satellites for communication relay think of the ROAMing rates they could charge NASA and the Martians that might ROAM onto there network!

Don't forget Astronauts could use SideKicks to communicate!

Re:lets wake up here (1)

MozeeToby (1163751) | more than 4 years ago | (#29770977)

As a nerd who absolutely thinks about money to be made in the space industry, I have to disagree. Right now, space is about exploration and science, but the money to be made when someone figures out how to mine an asteroid is enormous. And the amount of money that can be made if you put an automated multipurpose factory on the asteroid is even more (if nothing else, you can produce more mining equipement and speed up the process). It'll only take a single successful mission of that type to bootstrap us into space in a way that isn't possible without it.

That's what people don't understand when commercial groups talk about monetizing space. You hear things about solar power plants in orbit and everybody immediately jumps into how the launch costs make it impracticle. The idea isn't to launch the solar panels up, it's to build them in situ from material mined from NEOs. We can't do that yet, but the company that has the orbital solar concepts proven out when we can stands to make billions. If we can mine rocket fuel, air, and water from an NEO in addition to metals and trace elements... the possibilities for science, business, and colonization are very exciting.

Illudium Phosdex shortage! (1)

argent (18001) | more than 4 years ago | (#29769467)

"I have sent for you, Dodgers, because we are facing a crisis. The world supply of Illudium Phosdex, the shaving cream atom, is alarmingly low. Now we have reason to believe that the only remaining source is on Planet X, somewhere in this area."

"And you want me to find Planet X, eh?"

"Can you do it, Dodgers?

"Indubitubly, sir, because there's no one knows his way around outer space like... Duck Dodgers, in the twenty-fourth and a half
century!
"

Re:lets wake up here (2, Insightful)

Dragonslicer (991472) | more than 4 years ago | (#29770723)

Since there's barely anything useful on the Moon given the cost of getting it, and there's even LESS useful on Mars

Since you know the exact chemical composition of the entirety of the moon and Mars, would you mind sharing with the rest of us?

Re:lets wake up here (0, Flamebait)

Gothmolly (148874) | more than 4 years ago | (#29771147)

yes, its 2 parts douchebag and 1 part troll. Oh wait, that's the content of your post.

Wouldn't it make more sense.... (4, Interesting)

mark-t (151149) | more than 4 years ago | (#29768961)

... to park such a device at L4 or L5, where you wouldn't require *ANY* fuel to keep it in position?

Re:Wouldn't it make more sense.... (1, Informative)

Nadaka (224565) | more than 4 years ago | (#29769057)

sure, except that you are ~doubling the distance the signal has to travel.

Re:Wouldn't it make more sense.... (1)

oldspewey (1303305) | more than 4 years ago | (#29769277)

Not when Mars is occluded by the sun it wouldn't be double.

Re:Wouldn't it make more sense.... (1)

Impy the Impiuos Imp (442658) | more than 4 years ago | (#29770737)

Which would be the whole reason, IIRC. You only need to get around the sun once in a great while; the rest of the time it's simple line-of-sight.

Still, if this is closer than L5 even during occlusion, by several minutes, it could be worth it. I assume "only" 90 days of rocket time every 2+ years (I presume an ion drive) is a decent, long-term solution for such a satellite.

Re:Wouldn't it make more sense.... (1)

oldspewey (1303305) | more than 4 years ago | (#29771109)

And by the time we have a permanent human presence on Mars that necessitates this kind of year-round communication, some interesting new propulsion options might well be on the table.

Not quite (4, Informative)

pavon (30274) | more than 4 years ago | (#29769709)

Would it?

Mars has an aphelion (maximum distance from sun) of 250 Gm, and the Earth has an aphelion of 150 Gm. So when the sun is occluding their line of sight, they are on opposite sides of the sun and are separated by at most 400 Gm. If you had a satellite in the Earth's L4 or L5 point, then this would form a 150,350,400 Gm triangle with Mars. Thus the total signal distance would be 500 Gm. This would add 100 Gm, increasing the transit time by 5.5 minutes (from 22.2 to 27.7 minutes). Not as good as the solution presented but not twice as long.

Placing these in the Earth's orbit, rather than Mars', would have the added advantage of solving the solar occlusion problem for anything we send out into the solar system, not just for things on Mars.

Re:Not quite (3, Interesting)

Nadaka (224565) | more than 4 years ago | (#29770233)

The original article was mentioning satellites following/leading mars. With the satellites in mars Lagrange points, the distance would be longer, though not entirely double.

What the hell, I'll bother to do the math this time, using your figures of 150 Gm and 25 Gm that would result in a maximum distance from earth the a mars Lagrange point at about 350 Gm, plus the 250 Gm to mars gives a distance of ~600 Gm vs the strait line of 400 Gm. so its a ~50% increase in time.

Of course I could get pedantic and claim I was talking about the difference in time. But that would be fudging to cover my my lazy ass failing to math.

Re:Not quite (1)

VernonNemitz (581327) | more than 4 years ago | (#29770651)

Well, it would be 50% longer only when they actually needed to use the Lagrange satellites for communication with Mars. Most of the time the Sun is not in the way, so most of the time communications will be straight-line between Earth and Mars. Also, I might question the need for a SHORT additional delay in this communication; barring an SF gadget like an "ansible" it's not like we will ever being remotely controlling anything on Mars in real-time, since the minimum delay is always at least about 10 minutes.

Re:Not quite (1)

kehren77 (814078) | more than 4 years ago | (#29770485)

Placing these in the Earth's orbit, rather than Mars', would have the added advantage of solving the solar occlusion problem for anything we send out into the solar system, not just for things on Mars.

Plus putting in them in Earth's orbit keeps them closer for maintenance, refueling, etc.... Would suck to have to run out to Mars every time you need to fix a solar panel or something.

Re:Not quite (2, Informative)

Rakishi (759894) | more than 4 years ago | (#29770793)

Satellites as a rule aren't maintained or refueled, they're simply shoved somewhere where their decrepit hulks can hit anything useful. Cheaper that way oddly enough.

Re:Not quite (1)

shadocat2 (1387243) | more than 4 years ago | (#29770933)

This is a much more elegant solution.

Re:Wouldn't it make more sense.... (2, Informative)

hey (83763) | more than 4 years ago | (#29769077)

I didn't know about L4 and L5 so looked it up:
http://en.wikipedia.org/wiki/Lagrangian_point [wikipedia.org]

I think any satellite requires some fuel for thrusters to correct the orbit.

Re:Wouldn't it make more sense.... (2, Informative)

Chris Burke (6130) | more than 4 years ago | (#29769245)

L4 and L5 are actually the most stable lagrange points. The satellites would end up basically orbiting the lagrange point itself.

Re:Wouldn't it make more sense.... (3, Informative)

CheshireCatCO (185193) | more than 4 years ago | (#29769267)

Minor correction: they're the *only* stable Lagrange points. (And only then if the mass ratio of the primary and secondary body is high enough.)

Re:Wouldn't it make more sense.... (2, Funny)

mcgrew (92797) | more than 4 years ago | (#29769431)

...on the house outside LaGrange
Just let me know
If you want to go
To that home out on the range
They got a lot o' nice girls there...

-ZZ Top singing about outer space

Re:Wouldn't it make more sense.... (1)

MRe_nl (306212) | more than 4 years ago | (#29769907)

Take me up to LaGrange city
Where the girls are green
And the grass is pretty
Take me home (Oh, won't you please take me home)

-Guns'n Roses singing about Martian girls and space weed.

Re:Wouldn't it make more sense.... (0)

Anonymous Coward | more than 4 years ago | (#29770225)

Suck my dick

-James T. Kirk to the Martian girls.

Re:Wouldn't it make more sense.... (1)

buchner.johannes (1139593) | more than 4 years ago | (#29769575)

Planck and Herschel circulate around L2 of Earth-Moon. It needs little (but still) fuel to correct the orbit.

L4/L5 are better ... that's where the Trojans are ;-) (L4/L5 attract matter).

But as TorKlingberg points out below, the sun will move between Mars-L4/L5 or L4/L5-Earth.
I assume you planned to use L4/L5 of Sun/Mars. TFA suggests moving out of the ecliptic plane, circulating around Mars. Maybe some oscillation/periodicity can be exploited?

Re:Wouldn't it make more sense.... (3, Informative)

CrimsonAvenger (580665) | more than 4 years ago | (#29769895)

But as TorKlingberg points out below, the sun will move between Mars-L4/L5 or L4/L5-Earth.

Doesn't matter. If the sun is between Mars-L4/5 and Earth, then Mars is visible from Earth. Likewise, if the Sun is between Earth-L4/5 and Mars, then Mars is visible from Earth.

The only case where you need these relays is if the Sun is between Mars and Earth (or close enough to a direct line to make a hash of radio communications between Mars and Earth), and in any such case, none of the L4/5 points (either Mars or Earth) will be blocked from either of the two planets.

Re:Wouldn't it make more sense.... (2, Interesting)

techno-vampire (666512) | more than 4 years ago | (#29770105)

The only case where you need these relays is if the Sun is between Mars and Earth (or close enough to a direct line to make a hash of radio communications between Mars and Earth)

The idea isn't exactly new, you know. George O. Smith wrote a series of stories about a relay station in the L4 point of Venus, The Venus Equilateral series, [wikipedia.org] back in the '40s. It was a communications hub for the entire Solar System, and a hotbed of technological innovation. Great stories, still worth reading.

Re:Wouldn't it make more sense.... (1)

buchner.johannes (1139593) | more than 4 years ago | (#29770617)

You assume two redundant communication points: One on mars, and one in L4/5.

But the point is to use only one between Earth and Mars.

Re:Wouldn't it make more sense.... (2, Informative)

TorKlingberg (599697) | more than 4 years ago | (#29769103)

Wouldn't the Lagrange points also be occulted by the sun, though not at the same time as the planet? Also the distance would be a lot longer, as Nadaka said above.

Re:Wouldn't it make more sense.... (1)

MyLongNickName (822545) | more than 4 years ago | (#29769419)

I started to right the same message, but did some research first. The l4 and L5 points are 60 degrees off of the minor body's position. Therefore when Earth-Mars is out of sight, a communication satellite at this point could be used.

Re:Wouldn't it make more sense.... (4, Informative)

DutchUncle (826473) | more than 4 years ago | (#29769771)

Yes, and that's the whole point - when the planet is blocked, the Lagrange points would be visible to use for a relay.

Look up 1940's science fiction about the Venus Equilateral Relay Station by George O. Smith http://en.wikipedia.org/wiki/Venus_Equilateral [wikipedia.org]

Re:Wouldn't it make more sense.... (2, Insightful)

jamstar7 (694492) | more than 4 years ago | (#29770803)

Maybe I'm not getting it, but ion thrusters still need reaction mass, don't they? If these sats are under thrust for 90 days every 2 & a half years, eventually they'll run dry. From what I understand about the orbital parameters, they won't be cheap (in delta-vee) to reach for refueling, either. Now, we have a helluva time just scheduling a Hubble repair mission. How much more pain in the ass is a MarsComm sat refueling mission going to be? Or are they to be throwaways & replaced when they fall out of position, bone dry?

Re:Wouldn't it make more sense.... (2, Funny)

AGMW (594303) | more than 4 years ago | (#29770497)

Wouldn't the Lagrange points also be occulted by the sun

Witch ever way you slice there'd be no spell when both Earth and the satellites were blocked by the Sun so it's a wizard idea.

Re:Wouldn't it make more sense.... (3, Insightful)

BJ_Covert_Action (1499847) | more than 4 years ago | (#29769239)

The interviewee mentions that both LaGrange point orbits, as well as a few other options, are also being considered. Reading the interview, which is part of the article, can sometimes reveal useful information like this.

Also, to be pedantic, you would still need some fuel on a LaGrange spacecraft for station-keeping purposes. Though this amount would be minimal, you can't justifiably claim that you wouldn't need *ANY* fuel.

Cheers Mate.

Re:Wouldn't it make more sense.... (2, Funny)

RivenAleem (1590553) | more than 4 years ago | (#29769451)

Peer to peer downloads of heavy metal music would push the satellite out of the Lagrange point. Another reason why its BAD to fileshare

~Your friendly RIAA rep

Re:Wouldn't it make more sense.... (2, Interesting)

BenSchuarmer (922752) | more than 4 years ago | (#29770767)

I think the issue is better coverage on Mars.

As I read it, the spacecraft would be positioned so that they each cover half Mars with no overlap or gaps.

If the spacecraft were at the Legrange points, then the near/day side of Mars would have a large area that could see both spacecraft and far/night side of Mars would have a large area couldn't see either of them.

Re:Wouldn't it make more sense.... (4, Informative)

Solandri (704621) | more than 4 years ago | (#29770889)

... to park such a device at L4 or L5, where you wouldn't require *ANY* fuel to keep it in position?

The receiver/transmitter on these satellites and space probes are very small. Generally they transmit using only a few watts, and we rely on huge antennas like in the ubiquitous dishes in the Deep Space Network to gather enough of that minuscule signal to distinguish it from background noise. Going the other way, we use the same huge antennas to blast commands to these spacecraft at anywhere between 5-500 kW. By the time the signal reaches the spacecraft, it has dissipated substantially, but its original broadcast power was high enough that the spacecraft's relatively small antenna can still collect enough of it to distinguish the signal.

Putting a repeater spacecraft at the L4 or L5 points would place them a substantial distance from Mars. Consequently the repeater would need a very large antenna and large amounts of power (though not as big/much as earth-based antennas) in order to relay signals to/from a spacecraft on Mars. The idea presented in the paper is more akin to what we do right now with the two Mars Rovers and several of our Mars orbiters. The Rovers themselves have weak antennas and can't communicate directly with Earth except at low data rates. Instead, they transmit their data to the orbiters (same antenna can achieve higher bandwidth since the distance is much less), which then relay it to Earth using their much larger and more powerful antenna.

(Introduction to channel capacity [wikipedia.org] for those who may be wondering what the relationship is between data transmission speed and signal to noise ratio.)

Who needs full-time communications (5, Funny)

Anonymous Coward | more than 4 years ago | (#29768977)

Houston> We haven't talked for a day, what's up?
Mars rover> Hey, I moved one meter!
Houston> No shit!

Re:Who needs full-time communications (5, Funny)

oldspewey (1303305) | more than 4 years ago | (#29769295)

Wow, I had the exact same conversation with my unemployed brother-in-law yesterday!

Cita tion need ed (2, Informative)

Anonymous Coward | more than 4 years ago | (#29768987)

FYI: there is no article on Wikipedia to describe a non-Keplerian orbit.

Even 2 simple diagrams describing the 2 orbits types would help.

Re:Cita tion need ed (0)

Anonymous Coward | more than 4 years ago | (#29769485)

I envoke Rule 35.

Re:Cita tion need ed (2, Insightful)

Nyeerrmm (940927) | more than 4 years ago | (#29769807)

Go write it then. You've got the journal article to work off of, which should be all the citations you need, since I think this is the definitive work on the subject right now.

Re:Cita tion need ed (0)

Anonymous Coward | more than 4 years ago | (#29769819)

Well? What are you waiting for?

Re:Cita tion need ed (0)

Anonymous Coward | more than 4 years ago | (#29770319)

To my critics:

If knew the difference between the 2 orbit types I would have posted it here (with my /. account) and on Wikipedia.

Slow News Friday? (0)

Anonymous Coward | more than 4 years ago | (#29769013)

Please post more arcane papers. For examples, I highly
recommend arXiv.org [arxiv.org] :

from the home page: Open access to 565,038 e-prints in Physics, Mathematics, Computer Science, Quantitative Biology, Quantitative Finance and Statistics.

Yours In Yaznogorsk,
K. Trout

Re:Slow News Friday? (1)

hey (83763) | more than 4 years ago | (#29769091)

Booo, that paper was arcane but interesting.

Orbital resonance, anyone? (1)

flajann (658201) | more than 4 years ago | (#29769049)

I would've thought their may be an orbital resonance solution that wouldn't require any thrusters at all. But that may require an orbital resonance between Earth and Mars, a situation that clearly doesn't exist.

Still, there may be something exotic that could be done.

Eh? (2, Funny)

wcrowe (94389) | more than 4 years ago | (#29769061)

I understand "behind and below". WTF is "in front and ahead"?

Re:Eh? (0)

Anonymous Coward | more than 4 years ago | (#29769231)

Don't imagine yourself sitting on Mars, imagine yourself as an astronomer with a telescope on Earth. Looking at Mars, there could be things orbiting it which are in front or behind it (closer or further away to an Earth-bound observer), and things ahead or behind it (on Mars' orbital track).

Re:Eh? (1)

wcrowe (94389) | more than 4 years ago | (#29769349)

Ah. I was only thinking in terms of Mars' orbital track.

Re:Eh? (2, Insightful)

AP31R0N (723649) | more than 4 years ago | (#29769697)

Yup, prolly should have been "in front and above".

Re:Eh? (0)

Anonymous Coward | more than 4 years ago | (#29769725)

it's kdawson speak for "in front and above" I believe, but I can't be certain

Bandwidth (5, Insightful)

CheshireCatCO (185193) | more than 4 years ago | (#29769297)

This is slightly tangential, but worth noting I think:

This will be handy when we can't afford to lose contact with Mars for even a few days, but there's a bigger problem lurking in inter-planetary communications: bandwidth. We don't really have enough Deep Space Network dishes (particularly, the large 70-m ones) to talk to all of our missions as much as we should. We're sacrificing data collection on billion-dollar missions on a daily basis on the grounds that we don't have enough bandwidth to get it back. When we put people or even just more missions on Mars, that'll only get worse.

Re:Bandwidth (2, Funny)

Rennt (582550) | more than 4 years ago | (#29769589)

Yeah, net neutrality goes right out the window. Spare a thought for our poor Martin pioneers. No bittorrent for you!

Re:Bandwidth (2, Funny)

NEDHead (1651195) | more than 4 years ago | (#29770595)

Wireless is always less bandwidth than wired/fiber solutions. A direct, multistrand cable is called for.

Re:Bandwidth (1)

jamstar7 (694492) | more than 4 years ago | (#29770841)

Two words: Lunar dishes.

Put the comm dishes on the Moon someplace. I'd recommend a set of 3, equally spaced around the equator of the Moon, thus, it'll always have 1 dish at least looking in the right direction.

Second thought, a heavy comm laser setup, also Moon-based.

Re:Bandwidth (1)

CheshireCatCO (185193) | more than 4 years ago | (#29771391)

Why would putting them on the Moon help?

And the problem isn't having dishes pointing in the right directions, it's having too *few* of them. For example, when Saturn and Mars are near conjunction in our sky, we have to choose whether to talk to Saturn or Mars with the 70-m dish.

Re:Bandwidth (1)

khallow (566160) | more than 4 years ago | (#29771465)

That goes to a complaint I heard recently. Namely, that the US government eagerly spends billions to develop and launch these missions, and grudgingly spends millions to maintain them. It makes sense, if you realize that the primary purpose of these missions is to funnel money to the NASA supply chain, not to do space science.

so... the most important question (0, Redundant)

circletimessquare (444983) | more than 4 years ago | (#29769313)

what kind of latency are you getting?

can you play a fps with mars crew?

can a mars rover host a MMORPG?

Immature (5, Funny)

ZinnHelden (1549931) | more than 4 years ago | (#29769331)

Sorry, I tried to read the summary but I didn't make it past 'continually-thrusting'.

B Orbit? Borbit? Borat? (0)

Anonymous Coward | more than 4 years ago | (#29769341)

This article has animations and pictures of everything but the actual type of orbit the paper talks about.

Is it so difficult to actually include such a thing, so that we can imagine it?

Note: I'm not reading the paper, that's too much effort. I'd rather get my information fed to me on a plate. Although I will take the time to write this still.

How about.... (1)

Kjella (173770) | more than 4 years ago | (#29769385)

...we let go of the harakiri you're supposed to commit if you ever go out of cell phone range? I mean, surely we can outfit an expedition that doesn't need 24/7 babysitting from mission control, It's not like Columbus had queen Isabella call him up every night to ask "Are you there yet? Food supply ok? Your blood sugar values are low, you should eat more."

Re:How about.... (2, Insightful)

DutchUncle (826473) | more than 4 years ago | (#29769851)

Totally. Why do the Shuttle crews need to get woken up over the radio? Don't they have a clock? maybe a watch? There are self-winding mechanical ones with alarms, no batteries to wear out. It seemed childish in the Apollo age when I was a kid with my own alarm clock for school; it's downright stupid now.

ANKOS... (2, Funny)

smitty777 (1612557) | more than 4 years ago | (#29769443)

A New Kind Of Science...er...Orbit. I wonder if Wolfram will try to take credit for this, too. Maybe there's an automata to describe it.

For those who don't RTFA (3, Insightful)

Brett Buck (811747) | more than 4 years ago | (#29769545)

To clarify - this sort of "orbital" motion (not really "orbital" since it actively powered) is hardly a new idea. What is relatively new is the fact that you have engines that permit you do do it without prohibitive fuel consumption. It's different from a hovering rocket-propelled lander (like the DC-X) only in scale. The key feature, not clear in the article, is that you are intentionally thrusting along the local vertical, in the direction of gravity, to modify its effects. That was possible and everybody knew about it since, well, Newton figured out gravity. What we haven't been able to do is to maintain it for more than the briefest periods due to excess fuel consumption.

        The new part here is the Hall Current thruster, which is ~factor of 10 more efficient than traditional engines. The specific impulse of these is around 1800 seconds (lb-sec of impulse per lbm of fuel- hey I didn't invent the units, I just use them...) compared to maybe 180 for a hydrazine monopropellant thruster. These are not exactly "new" either, the Russkies have been using them for decades. Only recently has the western world begun to develop them, so it's new only in that sense. So the solution they are looking at is now looking reasonably practical, although no doubt still significantly limited by the fuel consumption.

        Brett

Re:For those who don't RTFA (1)

FireFury03 (653718) | more than 4 years ago | (#29769833)

The specific impulse of these is around 1800 seconds (lb-sec of impulse per lbm of fuel- hey I didn't invent the units, I just use them...)

That unit doesn't make sense - force and mass don't cancel each other out, even if you happen to be crazy and give the units the same name: lb-force is not the same thing as lb-mass.

To put it another way:
N × s / Kg
See - no identical units to cancel.

Re:For those who don't RTFA (2, Informative)

Brett Buck (811747) | more than 4 years ago | (#29770357)

Hey, ISP is in seconds, it's an industry standard. The SI version isn't any better - kgf-sec/kg. It makes more sense when you realize it's proportional to the exhaust velocity, which is in, say, feet/second.

      Brett

Re:For those who don't RTFA (1)

FireFury03 (653718) | more than 4 years ago | (#29770439)

>Hey, ISP is in seconds, it's an industry standard.

Might be standard, but it's still crazy. Using weight instead of mass means you have to know how much gravity it was calculated for (a figure that isn't specified anywhere in the units), and means that the value given for ISP will change depending on the gravitational force you assume is in effect.

The SI version isn't any better - kgf-sec/kg.

That isn't the SI version - there is no such SI unit as "kgf". The SI unit for force is Newtons, giving you "Newton seconds per kilogram", which makes a lot more sense since there are no hidden coefficients.

Re:For those who don't RTFA (4, Insightful)

radtea (464814) | more than 4 years ago | (#29771219)

Hey, ISP is in seconds, it's an industry standard.

But it shouldn't be. N*s/kg is the correct unit for specific impulse. "Seconds" is only used by American engineers who don't understand the difference between weight and mass.

When I was a kid I was deeply interested in space, but it wasn't until years later that I understood the meaning of Isp because of the idiotic convention of designating it in seconds, rather than force*time/mass, which makes its meaning completely obvious.

If you want to turn people off an understanding of the most basic aspects of space travel, by all means go ahead and keep using seconds for Isp. But it's really time for the United States to get with the rest of the world and abandon Imperial units, although I guess as an imperial power they seem like a natural fit.

[Ok, now wondering if this'll get more "troll" or "flamebait" mods. It should probably lean toward "flamebait", as the story is true: Isp in seconds really did confuse me for years. The egregious America-bashing is, well, egregious, so probably warrants a flamebait mod. But really, what's with the Imperial units, kids?]

Re:For those who don't RTFA (1)

John Hasler (414242) | more than 4 years ago | (#29770303)

These are not exactly "new" either, the Russkies have been using them for decades. Only recently has the western world begun to develop them, so it's new only in that sense.

Not quite. SERT [wikipedia.org]

Occult vs Occlude (1)

JSBiff (87824) | more than 4 years ago | (#29769569)

Slightly off-topic, but I have a question for the word-geeks out there. Now, I know that technically "Occults", used the way it is in this context, is technically correct (in fact, as far as I can tell, this is the *original* meaning of the word, and the other meanings have developed off of the original meaning, later). However, given that most people probably associate the word "Occult" with mysticism, mightn't it have been better to describing the Sun blocking communication by using the word Occlude, instead of Occult?

Re:Occult vs Occlude (0)

Anonymous Coward | more than 4 years ago | (#29770519)

No.

Why not above? (0)

Anonymous Coward | more than 4 years ago | (#29769613)

Why won't anyone just put a relay above the sun?
Put one below it too, and one orbiting the horizontal plane and you pretty much have 360 degree coverage of the solar system, outside of being on the shadow side of planets.

Surely there is a stable point somewhere above the sun?

Re:Why not above? (4, Informative)

MRe_nl (306212) | more than 4 years ago | (#29770241)

"Surely there is a stable point somewhere above the sun?"

No.

Gravity is always pulling you down, but there are places in the solar system where gravity balances out. These are called Lagrange points and space agencies use them as stable places to put spacecraft. If you're not in one of those places, you're happily going to fall on/in-to the object or end up in some sort of orbit going around the object, but you're not going to be motionless or synced up with anything.

All stable points within our solar system (L1/L5) are on the ecliptic plane iirc.

Use Solar Propulsion instead of propellants (2, Interesting)

KJSwartz (254652) | more than 4 years ago | (#29770367)

If we're THAT CLOSE to the sun, it would be interesting to see how big a solar sail would need to be for a 364.245 day parking orbit. Use the dark side of Mercury as Network Control.

Re:Use Solar Propulsion instead of propellants (0)

Anonymous Coward | more than 4 years ago | (#29770493)

You get the idea, a solar sail could be used to attempt to balance out the forces.
The solar sail reflects the light, but also channels any matter to be collected and used in an ion drive.

But the costs of putting it together might be the limiting factor in this case.

ping (0, Offtopic)

Hognoxious (631665) | more than 4 years ago | (#29770059)

I wonder what the ping times are like?

What about a Stationary Position about the Sun? (2, Interesting)

KJSwartz (254652) | more than 4 years ago | (#29770289)

First: What is the purpose of 24 hour communications? If you need SOS messaging, signal recovery, or a simple heartbeat, use the sun as the point-of-reference.
Second: A fleet of solar communications satellites could provide a solar GPS system.
Third: These satellites could use Solar Propulsion and "hover" at a fixed distance from adjacent satellites. Solar sails could serve as a foundation for power generation (focused beam) and for data reception.

Downsides: the sun is a noisy place for communications, as well as a dirty place to park objects with large surface areas.

What about Quantum states? (1)

QJimbo (779370) | more than 4 years ago | (#29771329)

From what I've read, using quantum techniques to communicate wouldn't be faster than light, but surely that would solve any line of sight issues?

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