Slashdot Mirror

Now that is a heck of a nice read. I am going to have to spend some time with this.

Reminds me of Atomic Rockets.

A far out planet could be useful for gravitational assists to the outer solar system.

Pedantically speaking... An actual gravity assist from the planet itself would be worth little - certainly not enough to justify the 1,000+ year diversion (not exaggerating) required to actually take advantage of it.

Getting a gravity assist is analogous to bouncing off of the assisting body. If the body is moving quickly and in an appropriate direction, the spacecraft can pick up a lot of speed (relative to the rest of the solar system) in the process. These conditions would certainly not apply to the hypothetical planet discussed above though:

1) A planet orbiting at that altitude would have an orbital velocity no more than ~7% that of Earth - maybe much less. A gravity assist cannot boost the velocity of the spacecraft by more than the velocity of the assisting body.

2) Achieving a worthwhile gravity assist requires waiting for the orbital phase of the assisting planet and the actual destination to line up right. This could be a loooonnnnggggg wait given that the planet in question would have an orbital period between about 3,000 and 40,000 years...

Having said that, if the planet just so happened to be in roughly the right place already, it might still be worth swinging by it for two reasons:

A) If it had a large moon in a relatively low orbit that was roughly aligned with the plane of the ecliptic, that moon might provide the gravity assist which the planet itself could not.

B) The point of closest approach to the planet may be a good place for an engine burn, to take advantage of the Oberth Effect (which is distinct from a true gravity assist).

Of course - all this "orbital ballet" gravity assist stuff is only necessary because our current propulsion technology is inadequate; any realistic plan for humans to explore the outer solar system would require an upgrade.

And as far as his comments about black-body radiation from such a structure, it doesn't seem terribly unreasonable for a civilization capable of such engineering such a megastructure in the first place, to have figured out how to convert heat energy into something more usable/consumable.

Like more heat at a lower temperature?

Forget Dyson Spheres. When they reverse thermodynamics, *then* I will be impressed.

http://www.projectrho.com/publ...

Basically everything except H3 mining that TFA seems to dislike is covered at Project Rho. Except that it's written way better and talks about solutions, not problems.

Next? It has already been done:

http://www.projectrho.com/publ...

I don't see how you conclude any of those things. Why would your weapon need to be the same as your propulsion system? Few, if any, current battle vehicles are arranged like that. A propulsion system and a weapon have very different design criteria. If this is just to be lightweight, then why couldn't you use the vehicle itself as a missile?

> You'll need to be a hole in space. So you need to be small enough to avoid detection, have minimal radar return, and your thermal signature needs to match the background of space.

That's effectively impossible as the background of space is 2 K or so. There is no stealth in space. http://www.projectrho.com/publ...

I'm not saying what you're saying is wrong; it's just one of the many ways that space battles could be fought. There's no reason to think it's the only way.

from http://www.projectrho.com/publ...
quote:
I'll believe in people settling Mars at about the same time I see people setting the Gobi Desert. The Gobi Desert is about a thousand times as hospitable as Mars and five hundred times cheaper and easier to reach. Nobody ever writes "Gobi Desert Opera" because, well, it's just kind of plonkingly obvious that there's no good reason to go there and live. It's ugly, it's inhospitable and there's no way to make it pay. Mars is just the same, really. We just romanticize it because it's so hard to reach.
end quote.

Basically, the x-rays will ignite the surface of the asteroid instead. If the material in the asteroid is sub-optimal for this purpose, there have been designs of turning a nuclear bomb into a kinetic weapon that should work in this regard. Basically the bomb sits in an x-ray reflective shell, and when the bomb explodes, the x-rays bounce around the shell before the exploded bits of the bomb destroy it and exit an aperture. At the end of the aperture is a large, dense block of x-ray absorbing material. This material is vaporized by the x-rays and is all traveling in a similar direction as the x-rays were all going in that general direction. This plasma moving at relativistic speeds then slams into the target like a nuclear shot gun blast. IIRC, this design was built for using nuclear bombs against space ships and it was estimated that it could direct 95% of the energy of the bomb at the intended target.

I second that. Masterful tech writing.

This description of Orion propulsion also describes the 'Casaba-Howitzer', a one-shot Orion optimized for a narrow, fast plasma jet. Here objective is more similar to Orion than punching through armor: the most complete, reliable and (as much as possible) directed transfer of energy. The Casaba-Howitzer concept is not even in the declassified SDI flava stuff that DOE is permitted to talk about.

We all love Delta-V-expensive solutions that involve maneuvering 'beside' or 'landing on' a threat (which by definition is heading straight towards us at 10-30kps. There are no cloverleafs in space, people! :) Landing Bruce Willis is out. Doing anything gentle or slow is out. I propose these be shelved for the 'Emergency' context. Parameters are strict. The best we might achieve is some 45 or less approach angle. By this I mean the vehicle's course, the explosion can be directed broadside, as timing allows. The final sequence of events requires precise micro/nanosecond timing. We know our computers are up to it.

Are the warheads? We know how to make warheads that detonate on timing, pressure and 'contact'. But speed is relative and conditions in atmosphere is a cushy affair, a device falling at terminal velocity or missile propelled. Can we assuredly produce a weapon that can range itself accurately or trigger in vacuum, on or just before contact at ~40kps?

And there should be at least three complete missions of them en route, each lagging far enough to escape detonation effects, have enough time to analyze a failure, upload firmware, or adjust course in case we have partial success. And it would br really nice if each mission embodied more than one general approach, or the ability to reconfigure for an alternate strategy... just in case there it becomes clear after the first that the primary will not work. And even an idea that shapes force of a nuclear explosion is a massive fail if a technical snafu has it pointing the wrong direction.

The price of failure is death. And embarrassment.

The person using a laser weapon would be wearing something to protect their eyes against the specific wavelength of the laser. If they weren't, then they're too stupid to deserve to keep their eyes. As noted elsewhere though, bystanders and burns are a little harder to deal with (though, if you're picking your targets right, if you get a stray reflection back to where you're standing, it should be diffuse enough to be little more than sunlight, or perhaps very minor skin burns - seeing as we would be talking about extremely short exposure times before it toasted the reflective surface). If you happened to walk in front of the beam however...

It is interesting seeing how even with an educated audience (ok, making assumptions about /. here... ;-), there is still little understanding about the actual technical aspects and limitations of real laser technology - /. seems more informed by sci-fi than by science (not necessarily your comment, but this discussion in general). No, mirrors aren't going to work. No, we can't carry around a handgun-sized laser with current energy storage tech. Yes, it's going to cause partial blindness to anyone nearby, but no, it's not going to set everything around it on fire due to scattering.

This is a good read for anyone interested in the science side of laser weapons: Atomic Rockets - Sidearms.

http://www.projectrho.com/public_html/rocket/spacewardetect.php#id--There_Ain't_No_Stealth_In_Space
Project Rho explains that in detail.

If you cannot move faster-than-light then your engines will give you away every time.

Except for a few people, nobody cares about Mars. Only need to see what the politicos and major decision makers are working on. Also from http://www.projectrho.com/rock...
"The Gobi Desert is about a thousand times as hospitable as Mars and five hundred times cheaper and easier to reach. Nobody ever writes "Gobi Desert Opera" because, well, it's just kind of plonkingly obvious that there's no good reason to go there and live. It's ugly, it's inhospitable and there's no way to make it pay. Mars is just the same, really. We just romanticize it because it's so hard to reach."

A manned mission to Mars has always been 20 years away and been presented like this for past 50 years (like fusion energy power plants are 10 years away which been presented like this for past 60 years). After a half century, maybe a different approach? Sorry I don't see how Orion or Musk's Dragon can reach Mars (supplies, food, machine shops to repair when things break down, radiation, microgravity, etc.). Then we got advocates always promoting their "One legged stool" http://hopsblog-hop.blogspot.c... for the Next Big Initiative.

Of all the stuff I read, Dennis Wingo in his book Moon Rush discusses real driver should be industrial expansion, "Deals of this size are done all the time, and think what having access to and rights over a billion kilos of platinum would do for your corporate portfolio." Wingo also discusses background of major programs Apollo, SEI, Augustine commissions I and II, and why certain decisions were made (and why many times nothing happened after). http://www.amazon.com/gp/produ...

I never understood why Star Trek ships had to establish a "standard orbit" to begin with. They have enormous amounts of power available along with the magic warp field. So why couldn't they keep themselves suspended in one spot above a planet, regardless of gravity?

Especially since they can apparently move from one planet to the next in a system in a matter of minutes - even using 'impulse engines' - which if they were obeying standard Newtonian physics would take days at best if they accelerated at 1G all the way. Well, I suppose they could be accelerating at multi-G speeds, since they've got wacky warp drive inertial compensators, but at that point any pretense that 'impulse drive is just standard Newtonian chucking mass out the back' is long gone.

This is also equivalent to about 10^5 megatons of TNT or 2000 Tsar Bombas.

But in fact, matter-antimatter collisions of bulk objects don't work like that -- it's hard for like particles and antiparticles to meet up (between matter-is-mostly-empty and the fact that an electron is just as attracted to a proton as to a positron) so the total annihilation occurs over some considerable time, and due to the energy punched out in the initial phases, it also occurs over a considerable volume. Not saying it wouldn't be hilariously destructive, just that it's not like some kind of giga-nuke.

here you go...
see ya next month...

There is no escape. Dream all you want--write stories about it, make movies about it. But we ain't leaving.

I've been less optimistic about concepts of colonizing Mars, particularly after reading this retro future website, http://www.projectrho.com/rocket/macguffinite.php

I'll believe in people settling Mars at about the same time I see people setting the Gobi Desert. The Gobi Desert is about a thousand times as hospitable as Mars and five hundred times cheaper and easier to reach. Nobody ever writes "Gobi Desert Opera" because, well, it's just kind of plonkingly obvious that there's no good reason to go there and live. It's ugly, it's inhospitable and there's no way to make it pay. Mars is just the same, really. We just romanticize it because it's so hard to reach.

I've heard that argument before, yet the main problem with it is that you can't just go and live in the Gobi Desert because it's surrounded by nations full of people. We're in plenty of inhospitable places because there's things there, or you can do something there that you can't do anywhere else. There are tons of deserts we're very concerned with the precise owner-occupiers and behavior thereof.

The benefit of say, another planet, is largely that you can do pretty much whatever you want there because there'll be effectively no one around for a very long time. Sure, we're probably not going to colonize Mars in the near future...but that isn't to say we're not going to want to try things. Like the first steps of terraforming (though I prefer Venus as the target for that - thicker atmosphere, sunnier, more gravity).

There is no escape. Dream all you want--write stories about it, make movies about it. But we ain't leaving.

I've been less optimistic about concepts of colonizing Mars, particularly after reading this retro future website, http://www.projectrho.com/rocket/macguffinite.php

I'll believe in people settling Mars at about the same time I see people setting the Gobi Desert. The Gobi Desert is about a thousand times as hospitable as Mars and five hundred times cheaper and easier to reach. Nobody ever writes "Gobi Desert Opera" because, well, it's just kind of plonkingly obvious that there's no good reason to go there and live. It's ugly, it's inhospitable and there's no way to make it pay. Mars is just the same, really. We just romanticize it because it's so hard to reach.

The better specialized postapocalyptech for earthmoving is http://en.wikipedia.org/wiki/Ox but for more general usage the http://en.wikipedia.org/wiki/Horse design is widely preferred.

http://www.projectrho.com/public_html/rocket/stellarcolony.php#id--Growing_a_Colony--The_Economics_of_Slaves

Now there is a more nasty implication of the horse-doesn't-need-United-Steel argument. If a new colony can economically utilize horses, they can also economically utilize slaves. Or indentured servitude or debt bondage, with the hapless people theoretically capable of buying their freedom, but in reality they will perpetually owe their soul to the company store.

Let's enslave this guy

http://tech.slashdot.org/comments.pl?sid=3231995&cid=41884829

Project Rho has a convenient chart that will illustrate the infeasibility of such trajectories for all current (NERVA-like or gas-core) designs.

http://www.projectrho.com/public_html/rocket/spacewardetect.php#nostealth

The problem is that most people get their "information" from TV shows and movies that have a limited special effects budget. And a need to be exciting enough to keep the audience interested.

Any form of energy that you put out will be detectable by your opponents at ranges that give them minutes or hours or days or years of reaction time. There's no surprise there.

If you attempt to screen your energy output then you need perfect knowledge of the exact location of ALL of the the enemy sensors.

So you send out decoys. But that means that you're really building additional drives exactly like your drive. And the enemy will detect them with minutes or hours or days or years to prepare. So why not just put weapons on them and use them as part of your fleet?

http://www.projectrho.com/public_html/rocket/spacewarintro.php

Space is 3 dimensional.
Space is FUCKING HUGE!
There is no stealth in space.
There are no quick course changes in space.

Jerry Pournelle was writing SF stories using suits just like this back in the 1970s. HERE is a page describing this suit, and including a quote from Pournelle's story "Exiles To Glory".

Manned Space Stations
There actually was a pretty good MacGuffinite back in the 1950's: Manned space stations. Werner von Braun had it all figured out in Collier's magazine.
[snip]
Ironically NASA destroyed this. NASA's push for computing power led to the development of the transistor and integrated circuit. Suddenly you could make weather satellites, communication satellites, and spy satellites "manned" by a few cubic centimeters of electronics. Bye-bye MacGuffinite.

and another [space launch vehicles]

If you build it, they will come:
This approach is an expensive leap of faith, but it actually might work. The basic idea is to just assume that there is some marvelous MacGuffinite out in space. So you create a company that provides affordable surface to orbit transport service. With such services available, suddenly you'll have an entire planet full of entrepreneurs trying figure out a way to make it pay.

You don't have to figure out the MacGuffinite(s), they will. All you have to do is make a reasonable profit off the people who have figured it out (or think they have). Remember, in the California Gold Rush of 1949, it was not the miners who grew rich, instead it was the merchants who sold supplies to the miners.

Another from the site:

Politics
I recently came across an amusing variation on the "If You Build it" argument. The subject was the US transcontinental railroad, with construction starting in the 1860s. In his book Railroaded: The Transcontinentals and the Making of Modern America, author Richard White points out that there was no economic reason for building the railroad. The motivation was mostly political. Which is a plausible motive. After all, politics was the main driver behind NASA's Apollo moon program.

It seems to me we are chasing fables. There is the Pirate and the Cowboy as portrayed in the movies but what they portrayed really never existed. Now it seems who will join that group is the Spaceman.

uhmm, ya know, I read all kinds of opinions and discussion. Here are a couple that illustrates this whole "colonizing space fallacy." Maybe we will have moon bases or on Mars but anyone counter these items?

from Rocketpunk and MacGuffinite, http://www.projectrho.com/rocket/macguffinite.php

• Manned Space Stations
  There actually was a pretty good MacGuffinite back in the 1950's: Manned space stations. Werner von Braun had it all figured out in Collier's magazine. [snip]
  Ironically NASA destroyed this. NASA's push for computing power led to the development of the transistor and integrated circuit. Suddenly you could make weather satellites, communication satellites, and spy satellites "manned" by a few cubic centimeters of electronics. Bye-bye MacGuffinite.

• Colonization
  I'll believe in people settling Mars at about the same time I see people setting the Gobi Desert. The Gobi Desert is about a thousand times as hospitable as Mars and five hundred times cheaper and easier to reach. Nobody ever writes "Gobi Desert Opera" because, well, it's just kind of plonkingly obvious that there's no good reason to go there and live. It's ugly, it's inhospitable and there's no way to make it pay. Mars is just the same, really. We just romanticize it because it's so hard to reach.

• [space launch vehicles] If you build it, they will come:
  This approach is an expensive leap of faith, but it actually might work. The basic idea is to just assume that there is some marvelous MacGuffinite out in space. So you create a company that provides affordable surface to orbit transport service. With such services available, suddenly you'll have an entire planet full of entrepreneurs trying figure out a way to make it pay. You don't have to figure out the MacGuffinite(s), they will. All you have to do is make a reasonable profit off the people who have figured it out (or think they have). Remember, in the California Gold Rush of 1949, it was not the miners who grew rich, instead it was the merchants who sold supplies to the miners.

• Politics
  I recently came across an amusing variation on the "If You Build it" argument. The subject was the US transcontinental railroad, with construction starting in the 1860s. In his book Railroaded: The Transcontinentals and the Making of Modern America, author Richard White points out that there was no economic reason for building the railroad. The motivation was mostly political. Which is a plausible motive. After all, politics was the main driver behind NASA's Apollo moon program.

----------- end quotes from website -----------

http://www.projectrho.com/rocket/enginelist.php#id--Ion

It's a great site which details (with lots of math) the various problems with space travel.

Actually this would be really useful in spacecraft designs. No more need to have huge radiators vulnerable on the side of the craft, just fire the refrigeration laser.
http://www.projectrho.com/rocket/basicdesign.php#id--Heat_Radiators

Yes Slightly pleased that for my novel I did suppose that LEDs would be greater than 100% efficient ( http://www.doubleudoubleudoubleu.co.uk/2011/06/sfap-chapter-55.html ) . Okay it was not meant to be taken seriously when I wrote it, but it looks like I wasn't that far off!

Except the fusion drives on the comets would make them visible as soon as you light up the fusion drives. At least, if anyone is watching... http://www.projectrho.com/rocket/spacewardetect.php#nostealth

stealth is extremely difficult in space. space shuttle maneuvering thrusters are detectable from the asteroid belt. http://www.projectrho.com/rocket/spacewardetect.php#nostealth

not sure if this was posted before but this website tries to show how a scientifically accurate spaceship would work, with calculations. It also includes space warfare http://www.projectrho.com/rocket/crossindex.php

There ain't no stealth in space. The site has a lot more interesting things about the topic at hand.

You didn't really Google.

If you had, you'd found plenty of sites like this one (use the nav menu in the top-right corner, the navigation on the site is whack), which discuss the topic ad nauseum und link to even more sites that do even more of it.

I doubt there will be anything in the comments to this story that you couldn't find there.

http://www.projectrho.com/rocket/spacewardetect.php

It's not overly clear, but you'll want to click on the "Show Topic List" in the upper right corner.

If you want to jump directly to conventional space weapons: http://www.projectrho.com/rocket/spacewarintro.php

Lots of good data here, from reality to various levels of sci-fi.: http://www.projectrho.com/rocket/spacewarintro.php

Well, there's the bomb-pumped X-ray lasers of Project Excalibur.

Then there's the bomb-pumped particle beams of project Casaba-Howitzer, weaponized versions of the Orion Drive's nuclear "pulse units"

Also, I just found the paper I mentioned earlier on fourth-generation (pure-fusion) nuclear weapons. By the way, I suspect they would actually be an excellent choice for launching an Orion-drive starship, or even an interplanetary cruiser, as they may be clean enough for a ground launch without causing a small but noticeable global spike in cancer rates.

Antimatter triggered fission is brick-simple and relatively trivial. Antimatter triggered fusion is ... harder.

Laser-initiated fusion is possible as well, perhaps replacing all your large high power equipment with a flux compression ("bomb-pumped") generator. (This is distinct from a "bomb pumped laser", which is a term referring to an x-ray laser powered by an atomic explosion)

The pure-fusion bombs spoken of by NicknamesAreStupid are also known in a few publications as "fourth generation nuclear weapons"; all that I've read were unclassified and linked to/suggested by my sci-fi authors' resource of choice, Atomic Rockets. Some of the conclusions worth noting? Deuterium-tritium reactions are by far the easiest to ignite, and therefore the only feasible reaction for these, and release substantially all of their energy in the form of neutron radiation. The good: It couples very efficiently to metallic armor, letting you get by with a smaller bomb. The bad: While there are no fission byproducts, neutron activation of nearby materials will leave behind a glowing crater, though specific neutron energy levels suggest the total level of fallout will be smaller than a conventional nuke's ground burst. The ugly: The politics. You just fielded and used a neutron bomb. Also ugly is what happens if a tank clad in depleted uranium armor is near the target point - you may have just accidentally forced fission in thirty tons of tank armor. I don't even want to think about the explosive yield of that; if you're curious, go read about the difference between a lead tamper and a depleted uranium tamper. Start at the second paragraph of the "design" section. Let's also consider that Tsar Bomba only weighed 30 tons, including the primary and fusion stages and superstructure.

TL;DR
your ten kiloton planned clean detonation may trigger a fifty megaton, unplanned and dirty detonation.

http://www.projectrho.com/rocket/misconceptions.php
A site devoted entirely to helping with exactly that issue.

I'm a member of the stardestroyer.net forums, and there are some very sharp people on that site who would be happy to give you a hand with the technical side of things. They also have a user-fiction section just for writing stories, and some of the ones posted there are pretty damn good.

Just be polite. And make sure you have a thick skin. And do your homework first.

As for your questions, I can take a stab at them...
As for the destination, the moon and Mars are the obvious choices, but what else would make sense?
Near Earth Asteroids, Venus (reasonably habitable 50 km up: http://en.wikipedia.org/wiki/Colonization_of_Venus#Aerostat_habitats_and_floating_cities), Phobos, Deimos. Moons of Saturn might work, Titan and Enceladus being the more interesting ones.

How long would it take to get there?
http://www.projectrho.com/rocket/appmissiontable.php
Also the rest of the atomic rockets site I just linked has very good stuff for just this type of question.

What could be the goals of the mission?
There are maybe three broad categories, I'd say: political (Why did we go to the moon anyway? To rub it in the Soviet's faces.), monetary, and scientific.
Beyond that, well, you tell me, you're the writer. He3 mining on the moon? Political/Religious refugees? Life found on Mars means everyone wants to go see it? There are a lot of semi-plausible explanations. Which is all you need to start a rattling good yarn (sometimes not even then).

Any events or tasks that could punctuate an otherwise predictably boring long trip?
Micrometeroid punches a hole in the ship. Solar CME event burps a lot of radiation at the ship. The engine stops working. The AE-35 communication dish develops a fault and they can't talk to earth. The plants (the ones that provide air and feed people, you know) get sick/die. The biologist comes unglued and murders someone. I mean, this is stuff off the top of my head, man.

And there's always turnaround day for continuous acceleration ships. (The fastest way to get anywhere in space besides FTL travel is a continuous acceleration route, where you burn the engine to speed up halfway to your destination, then flip the ship over and burn the engine to slow down. Flipping the ship you have to do with the engine off, so everyone goes weightless for a few hours or a day while the ship turns end for end.) In some universes this is traditionally accompanied by a celebration or a special dinner or something, along with funny things like (say) bolting the floor furniture to the ceiling or having the most junior officer head up dinner instead of the captain.

Any possible sightseeing for beautiful VFX shots?
Space is beautiful, kid. There are always good VFX shots.

What would be the crew?
Captain, doctor, science, communications, pilot, engineering (the astute among you will notice I'm actually listing off bridge positions from the original Star Trek...)
Ok, come on, kid, I'm not going to do all your homework for you. If you can't even be bothered to look up or think up common crew positions, why bother helping those who won't help themselves?

Seriously, most of this stuff could be answered with some intelligent usage of Wikipedia and Google and a few hours of spare time. I answered this because I was bored and was familiar with it, but if you actually care, why aren't you looking this up for yourself? If you did already, say that you did, but want geek's valuable opinions. (and they'll fall all over themselves to give it).

Because right now the summary looks like you are lazy and can't be arsed to look this stuff up yourself. Do your homework, and intelligent people will be much more interested in helping you help yourself.

I was going to suggest http://www.projectrho.com/rocket/, but based on your questions, I think a better place to start would be
http://tvtropes.org/pmwiki/pmwiki.php/Main/SpaceDoesNotWorkThatWay

Here's a good place to start/

Beat me to it. Atomic Rockets is an excellent jumping off point for all the things you'll need to consider, complete with references to how real science fiction writers have dealt with these things in the past. Lots of science, math, and more science and math. Did I mention the math? It's pretty much all there.
Also, it's darn fun to read. I consider that a bonus. Don't you?

http://www.projectrho.com/rocket/
Beware - extreme nerdism and math.
Make sure you click on the "show topic list" in the upper right of the page.

Not exactly in orbital bombardment, the full title was "Mining the Moon? - Dilemmas of Space Law". One of the topics explored was the use of space for warfare

You've already checked out Atomic Rockets and Rocketpunk Manifesto, I presume?

Actually, with our current technology - and the "Gas station" is intended to work with our current technology - you use Hohman Transfer Orbits to get from planet A to planet B, i.e. you burn you engine at full power for a few minutes at the start. coast along for a very long time, and then burn them again for a few minutes to get into Orbit around your target. For unmanned missions, you may take a detour around a few other planets for gravitational assists.

What you're describing is a torchship that can perform a Brachistochrone mission, which is only really feasible with ion drives, which have neglegible acceleration.

The Gas stations mentioned in TFA are probably to be "parked" in orbit around Earth or the target planet. For a return mission, having a fuel source at the target would simplify and accelerate the trips both ways significantly

If the US Military wants to not be seen, they can do it. This is probably some object they put up their for the enemy to track. They are very good at what they do!

This is space we're talking about. And There Ain't No Stealth In Space.

There is no such thing as stealth in space.

... yet... to our knowledge...

There is no such thing as stealth in space.

If we can assume that there exists an engine that is capable of interstellar travel, e.g., matter/antimatter, then the design of Daedalus is hopelessly out of date.

The problem with designs like this is that the more fuel you need, the more structure it entails, to hold and contain all that fuel and the rocket it pushes and especially the payload. It all has to be braced against acceleration. The more structure, the more fuel needed in turn, needing even more fuel, and so on. It's not an infinite loop by any means but the numbers go up very quickly.

Long ago, Powell and Pellegrino, with their "Valkyrie" project at Brookhaven Labs, showed that if you are not launching from a deep gravity well (i.e., the surface of a planet) it is vastly more efficient to PULL your payload. The engines go up front, and pull the payload along on cables. He later used this design in one of his novels, which isn't relevant here, but the cover has an artist's rendition of the Valkyrie type of vehicle. James Cameron, in an attempt to be scientifically accurate, also used a somewhat stylized variant of the Valkyrie design for his spaceship in the movie Avatar. (Again not directly relevant, but it shows that the science behind Valkyrie has become accepted by the mainstream.)

The pull design drastically reduces the mass of infrastructure needed to build the rocket, which in turn reduces the amount of fuel needed, or alternatively allows more fuel to be carried and used on the trip.

(1) is "very easy?" I don't think you can imageine the vast amount of fuel required to perform this little trick for a journey to mars - remember that at the start, you have to accelerate all the fuel for the rest of the journey as well. According tothis Nomogramm you need a DeltaV of about 3,5Mm/s, in comparison, a conventional (Hohmam Transfer) from Earth LEO to Mars capture Orbit takes just a bit more than 5km/s. Therefore, this becomes "very easy" as soon as we heve rockets that are at least 1000 times as powerful as the ones we have now (i.e. never).

An interesting conjecture, but wouldn't anything using reaction drives light itself up quite nicely when it moved around? That is one of the conclusions over at Atomic Rockets.

More like this.