What is Space travel: Definition and 116 Discussions

Space-A travel is a means by which members of United States Uniformed Services (United States Military, reservists and retirees, United States Department of Defense civilian personnel under certain circumstances), and these groups' family members, are permitted to travel on aircraft under the jurisdiction of the United States Department of Defense when excess capability allows.

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  1. C

    I Space travel question -- Does SR length contraction imply the travel time is half?

    Hello everyone, I've been learning about length contraction and started to ponder how it applies to space travel. If the Lorentz factor is 2 by traveling at .577c does that mean you would be able to get to the object in half the distance because the transformed length in your reference frame...
  2. elcaro

    Some ideas on interstellar space travel

    Science fiction is of course full of all kind of futuristic ideas about interstellar space travel and ways of propulsion, some more physically plausible then others. But within the current realm of what is physical possible, what could interstellar space travel be like? First you need a source...
  3. O

    B Can Unlimited Energy Launch Objects into Orbit Using Accelerator Technology?

    If an infinite amount of energy were available to create the lift mechanism for a space launch. What would be required to fire a 200lb object into low Earth orbit(160km) after speeding it up in a way similar to how the large hadron collider speeds up a particle. Assuming the launch vehicle...
  4. A

    Exploring the Final Frontier: Join Our Team at Robert Neal Higgins Incorporated!

    Hi Folks, Found a saved bookmark from an old science class somewhere. Should have been here working with all of you all these years, but worlds apart do much better with an exchange of art. So who would like to participate: interstellar travel; extra-dimensional movement; and temporal...
  5. I

    Using a minimized nuclear reactor for further space travel

    I have been thinking and I thought of a design that may, theoretically result in spacecraft being able to have a self sufficient energy source on board. Here’s my theory, if you have a minimized nuclear reactor (if building something like this is even possible given that the nuclear reaction...
  6. R

    How Does Space Travel Affect Natural Aging?

    Changes in the body that come from space travel resemble growing older, providing opportunities to perform aging studies on astronauts. https://www.nmn.com/news/how-does-space-travel-affect-natural-aging Any validity to this?
  7. B

    How Long Would Scifi Space Travel Really Take?

    The interesting thing about scifi space travel is that it remains hard even with scifi tech, so long you allow propellant and gravity limits to still exist. In a way it is kind of a good thing, only in that it prevents widespread easy RKV starship use. My question is how long would travel take...
  8. M

    NASA Which of these methods is the best bet for space propulsion?

    1.) Ion drive 2.) Black hole starship 3.) Fusion Rocket 4.) Fission sail https://en.m.wikipedia.org/wiki/Fission_... 5.) Halo drive https://arxiv.org/abs/1903.03423 6.) Horizon drive https://www.tsijournals.com/articles/pro... 7.) Pitch drive, Diametric drive, Disjunction drive...
  9. M

    Which of these methods of propulsion is “best” for future spaceflight?

    Summary: Which of these hypothetical propulsion methods is the best for a spacecraft during Interplanetary flight? Let’s just assume all at this point are cost-effective at the time. Consider the •Safety of the engine •The speed •The efficiency 1.) Monoatomic hydrogen propulsion 2.)...
  10. ckirmser

    Could a <1g acceleration vehicle escape Earth's gravity well

    Hello, all - A question has come back to tickle my brain. Could a vehicle with less than 1G of thrust manage to escape the Earth's gravity well? I'm thinking something like Space X's Falcon 9. As it landed, with just a little more thrust, it could go back up again, I would guess. So, if it...
  11. N

    On board a laser powered solar sail

    Can an on board laser be used to propel a solar sail spacecraft if the laser is pointed at the sails ? Would Newtons third law affect the laser and maybe prevent the ship from moving ? Thank you for answering my very ignorant questions. NineNinjas911
  12. P

    Limits to accelerate a spacecraft by spinning it in a circle

    The basic concept is to have your space probe(s) - likely nanocraft [1] on a spinning object in space which allows you to preserve the momentum you give it while accelerating it faster. Then once you are at a speed you can simply release the nanocraft in the direction you want it to go in. More...
  13. M

    Space Travel & Relativity: Is it Possible?

    I had a bit of a thought experiment the other day, does relativity mean that technically you couldn’t travel faster than the speed of light to the observer. But if you were traveling from Earth to another planet, could you technically be traveling faster than the speed of light relative to the...
  14. BTA

    Why would aliens come here? (resurrected)

    I asked myself this question today, found that exact question asked here (February 10, 2005)... and I could not say anything, not even a squeak. Well, boil that dustmote! "Why would aliens come here?" I ask and the voices in my head speak. We are far from the galactic center of an average...
  15. R

    Space Travel with balloon assist

    Near space travels with balloons. http://edition.cnn.com/2015/03/05/tech/balloons-fly-edge-of-space/index.html look at above link. balloons goes just 36 km above Earth surface. but Earth orbit is 100 km away. so my thinking is if we pump oxygen outside near helium balloon artificially when u...
  16. M

    B Could this FTL idea with a fast moving large mass be possibl

    Could this FTL idea with a fast moving large mass be possible? I have recently come up with a possible way to achieve faster-than-light (FTL) travel by using a high speed singularity or large mass. Background As everyone knows, according to relativity, under normal conditions, it is impossible...
  17. L

    The unsolved engineering of the "Space Ladder"

    Spent several hours reading about the approaches and methodology of engineering the conceptual idea of a space ladder. I had no idea it was such a relevant project still. I had a few thoughts on it though: 1. In every proposal it seems the objective was to build a "connect a here to b up...
  18. A

    So why is space travel so hurdlesome again?

    For some reason, whenever I see these documentaries on space travel, and how NASA explains its projects, they always make it sound like "OMG we'll be able to colonize space MAYBE a million years in the future, with super technology, yadda yadda" and "space travel is so difficult", but aside from...
  19. LaurelAnnyse

    Future of Space Travel: Ideas for a Fresh Take

    Yeah, pretty much what the title says. Who has cool ideas for the future of space travel?
  20. LaurelAnnyse

    Is it possible to build a single-stage spacecraft that can exit the atmosphere?

    Hey there! My name is Laurel, and I'm working on a short story with a friend about, among other thing, space travel. I've just got some questions about exiting the atmosphere in order to fly a spaceship around looking for other stuff. I don't want you to feel you have to over simplify things...
  21. Ranvir

    B Why is interstellar travel so hopelessly difficult?

    So, I have been thinking about TRAPPIST-1 and how far away that system is from us. It is 40ly away from Earth, according to our frame of reference. This is often put in a way that makes one think that even at speeds close to that of light, it will take almost 40 years to get there. The muons in...
  22. R

    Light beam propulsion without lasers?

    We now have the capability to do laser launch. The problem is the initial cost outlay for the lasers is still prohibitive to launch a sizable payload. The estimate of the payload you can launch to Earth orbit dependent on laser power is about 1 kg per megawatt. So to launch thousand kilo...
  23. gilakmesum

    Exploring the Possibility of Warp Machines for Space Travel

    Is it possible now that we can built a warp machine and put inside the spacecraft and traveling around the universe?
  24. A

    B Material for black hole travel

    So I have been watching COSMOS of late and in the 4th (I think) episode it states the possibility that other universes exist inside of black holes. I am aware of the immense strength of a black hole's gravitational pull so my question is this: Is there a material strong enough to resist it and...
  25. wolram

    Space Travel: Overcoming Cosmic Radiation Challenges

    This paper states that extended space travel would be harmful for astronauts, how would future space travel over come cosmic radiation https://www.sciencedaily.com/releases/2016/10/161010052832.htm
  26. allister109

    B Does water pressure decrease in zero gravity?

    me and my friend were talking on facebook and we couldn't think of an answer to the question, would water pressure decrease in zero G, you can see how far along we got before getting stuck in the picture belowhttps://www.physicsforums.com/attachments/105576
  27. Erenjaeger

    Age difference problem due to space travel

    Homework Statement The identical twins Speedo and Goslo join a migration from the Earth to Planet X, 19.0 ly away in a reference frame in which both planets are at rest. The twins, of the same age, depart at the same moment on different spacecraft . Speedo's spacecraft travels steadily at...
  28. Stefen

    B Da Vinci's flying machine meets solar sail?

    so the question has been previously answered as to what would happen if a fan was in the vacuum of space. but the responses I seen all ask what the fan would push on or up against. what if the fan where to push against light? solar sails are able to have a force push against them in space?
  29. J

    I Time Dilation in Hypothetical Faster-than-Light Travel

    This sounds like a homework question, but I promise you it's not (I'm not even a student). To be honest, the question is simply for my own personal curiosity, to test a theory about a video game. My question is this: If an astronaut traveled for 15 years (their time) at twice the speed of...
  30. DHF

    Writing: Input Wanted Designing a space ship and with the dust shield

    Hello everyone, I am designing a ship for my sci fi story and I need input regarding the shield. I am trying to make my story as hard sci fi as I can get away with. The story takes place a few centuries from now and details the first expedition to Alpha Centuri. The ship will have a cruising...
  31. N

    Space Travel Physics: Realistic 2D Simulation

    So, I have been designing a game that uses Lego models to create spaceships that you then maneuver on a floor and do battle with. And one of the goals of this game is to be as realistic as possible, within the limits of a 2D environment. With that in mind, I have created a system that...
  32. R

    Space Travel to Mars: Overcoming Atmosphere & Creating a Bus Stop in Space

    So off to Mars we go. But really how are we going to get there? The most expensive part of space travel is overcoming atmosphere. So you could say the biggest obstacle of space travel is Earth travel. It takes virtually no energy to cross space but it takes massive amounts to get into space...
  33. R

    About the resupply missions in "The Martian"

    Two instances were discussed in the film where unmanned cargo ships were mentioned to send up supplies to extend the time Whatney or the crew of the Hermes could survive. This brought back painful memories while watching the movie. It's such an obvious answer. In the space shuttle Columbia...
  34. mileymo

    Relative Time in Space: What Speed for 1 Day Equals 1 Day on Earth?

    What speed does a ship traveling through deep space need to travel at for 1 day on the ship to equal 1 day on earth?
  35. mileymo

    Travel to Light Speed: Acceleration & Deceleration

    How long/what distance would it take a spaceship (with a hypothetical propellant-less engine) to accelerate to near light speed, and secondly, how low long/what distance would it take to decelerate back to zero again?
  36. Z

    Is My Idea for a Small Ion-Engine Satellite Feasible and Original?

    Would it be possible to build an approximately 10x10x10 cm ion-engine to put on a cube sattelite? I am a university student, so we have a lot of tools, but not a lot of money. What do I need to consider and how much would it cost?
  37. R

    Who is RocketDr Miles and What Are His Areas of Expertise?

    Hello, I am Miles. My interests are very broad. I work in the fields of energy, communications, and space transportation, developing new systems that can hopefully solve some significant problems in these areas. My primary backgrounds are chemistry and electrical engineering, but I've...
  38. U

    Novel idea for space travel (launch track around the moon)

    What if we built an electromagnetic track around the circumference of the moon? We could then accelerate a spacecraft to a very high speed. In theory it would only be limited by the strength of the materials holding the craft to the track and the centripetal acceleration that the craft/people...
  39. Quotidian

    Earth-Like Planet orbits Sun-Like Star

    That, anyway, is the headline in today's news, regarding the interesting discovery announced by NASA overnight of the planet dubbed Kepler-452b. As I understand it, the properties of the planet are inferred from spectral analysis of its effects on the light from the star which it orbits...
  40. DHF

    Need help figuring out a possible fusion engine

    Hello, I am in the process of writing space based sci fi novella, I made a few posts last year and earlier this year regarding different aspects of the ship and crew. If anyone is interested, I wanted to concentrate on the fusion engine of the ship itself and hopefully come up with a feasible...
  41. L

    An observation about relativistic space travel....

    I suppose I am not the first to notice this, but if you are going at say, 0.999c you will have shrunk by a factor of about 20 and everything else on the craft. Suppose the spacecraft is 2000 meters long, at 0.999c it will shrink to about 100 meters long. So suppose a person 2 meters tall...
  42. P

    What would it be like to be at a Lagrange Point?

    According to this NASA factsheet (http://www.nasa.gov/pdf/664158main_sls_fs_master.pdf ) on the Space Launch System (SLS), NASA identifies missions to a Lagrange point as a possibility. From what I understand, a Lagrange point is simply a point where the gravitational fields of two massive...
  43. C

    Can you "condense" a magnetic field and use a precision magnetic "beam" for space travel?

    Hey all, So I've been writing a hard science fiction novel and need real answers from someone who understands the fields better than I ( I have no formal education outside basic high school classes in physics) The problem I have is I'm not a fan of faster than light travel but I need a way for...
  44. D

    Centrifugal Spaceship Accelerator

    Suppose we launch two ships and move them close to the Sun. They have solar collectors and can absorb a massive amount of energy thanks to their proximity to the Sun. The ships are connected by a 1000 meter long rod of titanium, and each ship's rocket is position opposite the other's, so that...
  45. K

    Special relativity question: space travel and relativity of time

    Homework Statement You are 20 years old and embark on a mission to a star system that is 200 light-years away. Your ship leaves Earth in 2013 and travels at 0.999c. You do not spend much time at the destination, just head back to Earth. What year is it when you arrive back on Earth? How old...
  46. Keith

    Question about space travel and the human body

    Hello I have a question that's been bothering me for a while now and I figured I'd post it here to see if anyone could put my mind at ease. (Sorry if I accidentally posted this in the wrong place) Given that people can only withstand a certain amount of force on their bodies (about 5 Gs)...
  47. K

    Your choice of least facepalm-able space travel mechanism

    Your choice of least "facepalm-able" space travel mechanism If I may use the "facepalm" meter of Sci-Fi hardness. Examples The film Gravity, in which only the astronauts in your audience would complain loudly about technical details such as how quickly Sandra took off her space suit, has an...
  48. H

    Copenhagen Suborbitals open source space travel

    Very interesting bunch of guys trying to get a man into suborbit as cheap as possible. Found their website and youtube videos links at the bottom. Thought I would share. They have interesting video's of engine tests as they try to design the first rocket to send a man into space...
  49. phys-if

    Time Travel, Space Travel, Speed The Earths Movement, Speed Of Light

    I'm not sure if this is the right area of the forums. If it's not. Tell me which area would be better and I'll post this there. Time Travel- Would have to be space travel... and possibly faster than light If the time traveled and the time it takes to travel took less time to travel...