# Tag Info

33

To expand on Cort's comment. Propulsion in space is too costly and distances too great for a dogfight to happen. With modern tech, space combat is limited to more of an artillery duel between satellites that are on more or less fixed trajectories. If they start trying to move around too much they are going to just end up falling into the atmosphere or ...

20

Could the characters go to the space and colonize Mars or stay in a sustainable orbit around earth? NO, for several reasons: As of today, we are not yet capable of even sending a human to Mars, let alone keeping him/her alive there Non-military rockets are fueled with highly unstable chemicals. One doesn't simply fill their tanks and leave them parked for ...

16

The short answer is jerky and abrupt, but the longer answer is far more interesting... First of all, the preceding answers explain why fighter combat in space is really a bad idea; it's not an efficient use of propellants or fuels, and you're far better off doing what was done in naval warfare; focusing on a smaller number of larger ships with REALLY big, ...

13

Alright, this is my first answer on Stack Exchange, so let me know if I've made any grave mistakes in my analysis. These numbers are definitely back of the envelope calculations, but they do give a good picture of what's going on in your ship. TL;DR Yes, it will rotate the ship, but it's nothing that the ship's thrusters can't compensate for if your ship ...

11

There won't be any dogfights in space without the science-fiction tag. The reason is that we have been toying with lasers for a long time. The YAL-1 project was cancelled, yes, but it worked kinda well in 2014. If we are going to space, we are going to have better technology. The lack of an atmosphere will also make it much easier to hit stuff with lasers. ...

10

Could the characters use a pre assembled rocket to escape Earth and colonize Mars? At best it is very dubious, for reasons that L. Dutch already enumerated. If space travel is much easier in your setting, this might be more plausible, but it is basically impractical from a present-day or near-future point of view. the virus [has] no cure, meaning that ...

9

Yes. It can be lighter and more nimble than a multi-purpose aerospace fighter. It can also be heavier and more nimble than a multi-purpose aerospace fighter. 1 - it doesn't need flight control surfaces / airfoils or their hydraulic and electrical control systems to fly in-atmosphere. Instead it just needs strategically placed RCS thrusters and their ...

9

Maybe. It all depends. Trees rely on soil for a lot of things, and the alien soil would need to supply it and also refrain from being harmful. Not poison the tree: Some extraterrestrial soils are actively poisonous. (Mars' soil, for example, is highly oxidizing and would, untreated, almost certainly kill anything planted in it.) Retain water: Soil holds ...

8

Batteries and liquid hydrogen. Your ship uses as its engines a quartet of electric ion thrusters which fire hydrogen plasma (ionized hydrogen) at a significant fraction of the speed of light. Each thruster can rotate 360 degrees, though will not fire when pointing at the ship (that is bad for the ship and occupants). Combinations of thrusters confer ...

7

You are better off using lichens. A lichen (/ˈlaɪkən/, LEYE-ken or (USA) /ˈlɪtʃən/, LICH-en) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship. The combined lichen has properties different from those of its component organisms. They are the first organism to ...

7

In order to stay physically "accurate", a jump drive cannot create or destroy energy or momentum. This means the drive has the following limitations: Momentum conservation To comply with momentum conservation, your velocity and direction before a jump is the same as what you'll have afterwards. If you are in orbit on one planet, you better go to the right ...

6

A charged particle passing through the magnetic field has no work done to it. It’s trajectory changes but not its energy. The magnetic field won’t alter the path of neutral atoms, neutrons, or light produced by the Casaba Howitzer. And, plasma’s are a state of matter dominated by their internal electric and magnetic fields. The individual atoms of plasma ...

5

Maybe, it depends on the AI L. Dutch already pointed out everything there is to say about a lone mans chance for space colonisation. But you mentioned that he has a "life-like AI". I'll assume for the purpose of this answer that it is an artificial general intelligence (AGI) and not an artifical narrow intelligence (ANI) like we got today. The protagonist ...

5

Your plants will most likely die as they don't have the supporting ecosystem in the soil. If you look at the evolutionary timescales, land based (read as soil inhabiting) plants are first thought to have evolved on Earth around 700 million years ago, but life first formed on the planet a lot earlier; around 3.5 billion years old, probably around 1 billion ...

5

Beamed power might be of interest: since these fighters remain close to the mothership, the mothership could supply them with energy via laser or microwave beams that they converted back into electricity for use in weapons and propulsion. This would allow your fighters to be smaller and lighter because they didn't have to lug around a power source, but it ...

4

The general problem will always be supplies. Be it in earth orbit or on Mars, you will need food, water, oxygen, power. In orbit you will also need a supply of mass for keeping in orbit. The ISS for instance is not self sufficient, based on this answer. it needs resupplies about every 120 days. Now that is for a space station with more than 1 person on it, ...

4

1G for an hour is an astonishing amount of fuel for a space vehicle. It doesn't sound like much for an air breather, but space vehicles have to hold onto their own reaction mass. 9.8m/s^2 for 3600 seconds is 35km/s of delta-V, which is how rockets measure these capabilities. 35km/s is a lot. That's almost enough to escape Earth's gravity well and head ...

4

In space, everything is ballistic in nature. It would be smooth, but not graceful. Both ships would be struggling to stay within their optimum ranges, and out maneuver the tracking speed of the enemy guns. The whole thing devolves into firing mass drivers at each other from miles (and miles) away, then adjusting position, so that hopefully, the other ...

3

I would go for the Alcubierre drive. https://en.m.wikipedia.org/wiki/Alcubierre_drive The alcubierre drive circumvents many problems of FTL travel. The ship can be virtually at a standstill and experience no time dilation or other relative effects while the ship rides a sort of wave of gravity/space to its destination, and this wave does move faster than ...

3

Space is not an ocean, and there is no inherent need for "fighters". We use fighters on aircraft carriers because we are dealing with two different fluid mediums, but in space, the only advantage of a larger vehicle is more mass or volume. A "space fighter" can effectively do away with the "spacecraft" altogether. the 1980 era "Brilliant Pebble" interceptor ...

3

Simplest case: fire the projectile in radial direction. The sum momentum of the whole system has to stay equal.  \bar I_\text{ship} = m_\text{ship} \bar v_\text{projectile} \\ \bar I_\text{projectile} = m_\text{projectile} \bar v_\text{projectile} \\ \Sigma \bar I = \bar I_\text{ship} + \bar I_\text{projectile} = \text{const.} \\ m_\text{ship,t0} \bar ...

3

In the general case of current and recent human space stations: probably yes. Salyut-7 froze up after a few months without power, and the repair crew had to wear furs (because they were Russians, and so of course they had furs). In the specific case of the ISS... not sure, maybe yes. The ISS has a fairly hefty liquid cooling system with some big radiators ...

2

Use a heat pump to pump heat into an extremity until it is hot enough to radiate light. This will happen at the lowest temperature with what are called black bodies, but anything will radiate light once it reaches the Draper point. Even if it doesn't radiate light, you can still concentrate heat with a heat pump. That will effectively cool most of the ...

2

Not trees, trees are delicate sensitive things, though they may not seem it at first glance. You want weeds, dandelions, horsetail, bindweed, knotweed, grass. Plants that will grow out of a crack in concrete and call it a good home. Plants that your every effort to annihilate has knocked 6 weeks growth out of and look who's back. It'll take you a while to ...

2

Nuclear Rocket is the only solution within ~100 years... Chemical rockets do not work Chemical rockets do not work because of the rocket equation. You have to carry your own fuel, so you need a very high effective exhaust velocity. See this table, here. Thrust is based on conservation of momentum ($mv$) between you and your fuel. If your $v$ is low, you ...

2

Yes. There many reasons in other answers, but I want to point out the major one: You can travel to Mars and back (low orbit - low orbit) for the same amount of fuel as just to get to low Earth orbit, and still have some spare to get to the Moon orbit. Interplanatery transition requier much less energy, than jumping out of gravity well.

2

Basically yes. If you substantially decrease the scope of a vehicle, you typically can design it to be much better at what's still in scope. In particular, landing and taking of is a monumental challenge. Taking off takes somewhere around 8 km/s of delta-V. That is a tremendous amount of fuel, which is why rockets are so big. There's effort to try to ...

2

The AI and the rocket are both relatively easy compared to making a sustainable colony which isn't on earth. Regardless of which rock you stick it on, or even if you just put it in orbit, you are looking at building an enormous green house able to sustain a human population large enough to be genetically viable. It would be HUGE. It would also be ...

2

It's a tall order... Based on OP's description of the AI, it has no prior knowledge of space travel, engineering or how to sustain life. While I believe that this knowledge could be gained over time, it would require extensive human assistance to interpret and filter the available data. The crux of the issue is that the AI needs feedback on whether it did a ...

2

There's been a few realisic approaches to combat in space in various novels. I liked Niven's one in Protector - the assailant drops a bomb out the back of the ship, and a few days later there's an explosion as the pursuing craft hits it. But, that's not going to make for good TV! Perhaps the next best one is the approach used by Peter Hamilton, his ships ...

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