What is Spacecraft: Definition and 221 Discussions

A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, planetary exploration, and transportation of humans and cargo. All spacecraft except single-stage-to-orbit vehicles cannot get into space on their own, and require a launch vehicle (carrier rocket).
On a sub-orbital spaceflight, a space vehicle enters space and then returns to the surface, without having gained sufficient energy or velocity to make a full orbit of the Earth. For orbital spaceflights, spacecraft enter closed orbits around the Earth or around other celestial bodies. Spacecraft used for human spaceflight carry people on board as crew or passengers from start or on orbit (space stations) only, whereas those used for robotic space missions operate either autonomously or telerobotically. Robotic spacecraft used to support scientific research are space probes. Robotic spacecraft that remain in orbit around a planetary body are artificial satellites. To date, only a handful of interstellar probes, such as Pioneer 10 and 11, Voyager 1 and 2, and New Horizons, are on trajectories that leave the Solar System.
Orbital spacecraft may be recoverable or not. Most are not. Recoverable spacecraft may be subdivided by method of reentry to Earth into non-winged space capsules and winged spaceplanes. Recoverable spacecraft may be reusable (can be launched again or several times, like the SpaceX Dragon and the Space Shuttle orbiters) or expendable (like the Soyuz). In recent years, we are seeing more space agencies tending towards reusable spacecraft.
Humanity has achieved space flight but only a few nations have the technology for orbital launches: Russia (RSA or "Roscosmos"), the United States (NASA), the member states of the European Space Agency (ESA), Japan (JAXA), China (CNSA), India (ISRO), Taiwan (National Chung-Shan Institute of Science and Technology, Taiwan National Space Organization (NSPO), Israel (ISA), Iran (ISA), and North Korea (NADA). In addition, several private companies have developed or are developing the technology for orbital launches, independently from government agencies. The most prominent examples of such companies are SpaceX and Blue Origin.

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  1. F

    Force of Earth's gravity on a spacecraft

    Calculate the force (in Newtons) of Earth's gravity on a spacecraft 12900 km ABOVE the Earth's surface if its mass is 1410 kg.Give 3 sig figs.Be careful with your units! Again, here I know force is mass times acceleration, so would it just be 1410 times 9.8? The thing that worries me is...
  2. B

    Calculate Speed & Induced EMF of Spacecraft

    Homework Statement A spacecraft is in a circular orbit of radius 3.1 X 10^4 km around a 1.9 X 10^30 kg pulsar. The magnetic field of the pulsar at that radial distance is 1.4 X 10^2 T directed perpendicular to the velocity of the spacecraft . The spacecraft is 0.20 km long with a radius...
  3. C

    Launch Velocity of Spacecraft at ISS: Solving for v_L

    If we launch a satellite to a circular orbit around the Earth at height 357.1 km, to find the velocity needed at launch, do we just set the energies equal?: - \frac {\mu}{2\left(r_E + h\right)} = \frac {v_L^2}{2} - \frac {\mu}{r_E} and then solve for v_L? \mu = GM, where M is the mass of the...
  4. J

    Fusion Propulsion for Spacecraft

    I found this presentation on Fusion Propulsion here: http://fti.neep.wisc.edu/presentations/jfs_jannaf_1205.pdf" The Gas Dynamic Mirror seemed the most interesting and I got a lot of Google hits on it, but here are some guys working on actual proof of concept hardware...
  5. marcus

    New spacecraft starts taking early universe data

    Planck craft launched May 14 is now in position and is operating. ESA says it began taking scientific data yesterday June 14. Going around the sun, about 1 million miles or 1.5 million km farther out than the Earth is. http://www.rssd.esa.int/index.php?project=PLANCK&page=dev_news...
  6. A

    Is It Possible to Reach the Speed of Light with a Spacecraft?

    If you had a spaceship travleing at half the speed of light then shot a bulit at half the speed of light again, would the bulit appear to go the speed of light relative to an outside obverver? (All preposed in theory, of cource.)
  7. Y

    Help Spring Avarage acceleration and Spring Constant in a Spacecraft

    Help Spring Avarage acceleration and Spring Constant in a Spacecraft ! Homework Statement In NASA’s current concept, the lander has 4 legs, each with a plate on the end that will set firmly on the surface. Each leg has a spring to act as a shock absorber and each shock will compress 30 cm...
  8. A

    I have several questions in in satellite,space research and spacecraft

    Hi all, In fact I have several questions, especially in satellite,space research and spacecraft . mainly i target by my questions to get the knowledge in electronics,communication and physics.so,i want to have an open discussion for my benefit and so others. 1-I want to know some...
  9. C

    Relativity- stars and spacecraft.

    1.a.) A star is 450 light years from earth. i) what is the minimum time a spacecraft could make a return trip to this star? ii)How fast should the spacecraft travel to make the journey in 30 astranaught years? iii) What is the distance of eart to this star as measured by the astronauts on...
  10. N

    Momentum Conservation in a Swapping Chair Scenario in a Spacecraft

    Momentum in a spacecraft , please help! Homework Statement John (90kg) and Julie (60kg) are in a spacecraft (50kg). They swap chairs, which are 4m apart, located equal distances from the Centre of Mass of the spacecraft . Questions: Why does the spacecraft NOT move after they take their...
  11. J

    Exploring the Constant Speed of Light in a Moving Spacecraft

    I know there is an answer to this somewhere, so please forgive me for not being able to see it :) When people say that light will always be measured at a constant speed, no matter where you are, what do they mean? Say we are in a spaceship which is standing still. Inside the spaceship, we...
  12. C

    Can Humans Survive in a Spacecraft to the Moon?

    someone told me that it is impossible for a human being to survive in a spacecraft while traveling to the moon due to intense radiation somewhere in space that they would have to cross. is this true or just a hoax? I am not starting a conspiracy i just want a specific scientific answer on the...
  13. L

    Spacecraft Acceleration Question

    Homework Statement On a spacecraft , two engines are turned on for 684s at a moment when the velocity of the craft has x and y components of Vox=4370 m/s and Voy = 6280 m/s. When the engines are firing, the craft undergoes a displacement that has components of x= 4.11x10^6m and y =...
  14. P

    Calculate the orbital period of a spacecraft around the moon

    1. During an Apollo lunar landing mission, the command module continued to orbit the Moon at an altitude of 100km. How long did it take to go around the Moon once? 2. T= 2(pi)(r^3/2) / root (GM) mass of moon = 7.35 X 10^22 radius of moon= 1.74 X 10^6 3. I think that is the...
  15. chemisttree

    Spacecraft discovers solar winds are weakening.

    The Ulysses spacecraft , launched in 1990 and now in a polar orbit around the sun at a distance of roughly 240 million miles, is http://www.astronomy.com/asy/default.aspx?c=a&id=7424"!(?) How does he know that? I'm going to give him a call this afternoon... Anyone notice an increase in...
  16. F

    Time dilation and the pioneer spacecraft

    I've been thinking about this for a while but never got around to asking this. This has two parts. First, I understand that time and matter are closely related and that time slows down when in proximity to more matter. So, time on the moon is faster than time on Earth and time on Jupiter is...
  17. B

    Acceleration of voyager spacecraft

    Could the anomalous acceleration of the voyager spacecraft towards the sun be explained by its surface becoming electrically charged by friction with dust particles and the interaction of the electric charges with the sun's magnetic field?
  18. T

    Spacecraft Deep Impact - Comet's mass

    Homework Statement On July 4, 2005, the NASA spacecraft Deep Impact fired a projectile onto the surface of Comet Tempel 1. This comet is about 9.0 {\rm km} across. Observations of surface debris released by the impact showed that dust with a speed as low as 1.0 {\rm m/s} was able to escape...
  19. L

    More Spacecraft Velocity Anomalies

    Number 857 #2, February 28, 2008 by Phil Schewe More Spacecraft Velocity Anomalies A new look at the trajectories for various spacecraft as they fly past the Earth finds in each case a tiny amount of surplus velocity. For craft that pursue a path mostly symmetrical with respect to the...
  20. R

    How Do You Calculate the Semi-Minor Axis for a Spacecraft's Orbit?

    Sending a spacecraft to mArs! Help! pLease! okay guys so you have to open this file to read the question accuretely.. i have done some calculations but not sure if they are correct. So just this as best as i can, fist i figure out my semi-minor axis = a by 150km +150 KM +230 km...
  21. A

    Spacecraft to jupiter question

    Ok, so this is a homework question so i assume i put it in this forum (i'm new to this). I have been going over this for the longest time and have no clue on how to solve it please help. The marduk spacecraft will be lifted to low orbit using a traditional chemical rocket Rei=5x10^5 m...
  22. K

    Spacecraft orbiting sun, change in velocity

    Homework Statement A spacecraft is initially in a circular orbit of the sun at the Earth's orbital radius. It uses a single brief rocket thrust parallel to it's velocity to put it in a new orbit with aphelion distance equal to the radius of Jupiter's orbit. What is the ratio of the...
  23. S

    What is the Weight of a Spacecraft at Various Distances from Earth?

    Homework Statement The radius of the Earth is about 6.38E3 km. A 7.38E3 N spacecraft travels away from Earth. What is the weight of the spacecraft at the following disatnaces. a)6.38E3 km b)1.31E4 km Homework Equations F=GMeMship/r^2 The Attempt at a Solution but that...
  24. C

    Gravitational question (spacecraft)

    Homework Statement An unmanned spacecraft is in a circular orbit around the moon, observing the lunar surface from an altitude of 52.0 km. To the dismay of scientists on earth, an electrical fault causes an on-board thruster to fire, decreasing the speed of the spacecraft by 27.0 m/s...
  25. M

    Spacecraft vs Alien on a spherical planet

    Here's a problem which I encountered a while ago: "There is an alien on the surface of a spherical planet. The alien can run at a top speed of u. An alien hunter is hunting the alien in his spaceship which can fly at a top speed of v. Once the hunter sees the alien, he fires, and the alien...
  26. E

    How would you observe outside events on a spacecraft?

    If you were traveling near the speed of light on a spacecraft moving away from the Earth how you would you observe events happening on the earth, at normal speed or in slow motion? I can't work this out because I know light is always gaining on you at C even if you are traveling close to the...
  27. M

    Calculate the force of gravity on a spacecraft

    1. Homework Statement Calculate the force of gravity on a spacecraft 19200 km (3 Earth radii) above the Earth's surface if its mass is 1500 kg. 2. Homework Equations Fg=[(G)(M spacecraft )(Mearth)]/r^2=ma. 3. The Attempt at a Solution...
  28. R

    Force question involving an asteroid and spacecraft

    Homework Statement This is a 5-part problem. In June 1997 the NEAR spacecraft ("Near Earth Asteroid Rendezvous"; see http://near.jhuapl.edu/), on its way to photograph the asteroid Eros, passed within D=1200 km of asteroid Mathilde at a speed of 10 km/s relative to the asteroid...
  29. B

    Time dilation spacecraft travel problem

    Problem: How fast must a spacecraft travel relative to the Earth for each day on the Earth to correspond to 2 days on the earth? My solution: proper time = 1 day = 86400 seconds time on space craft= 2 days= 172800 seconds relavant equation: t=t(0)/(sqrt(1-v^2/c^2) I would plug in...
  30. M

    UFO-Inspired Future Spacecraft: Faster Than Mach 4?

    Hi don't know if I am in the right area but i have a random question about future spacecraft and the speed they travel. the rumor of ufo's are known the be a flat sphere shape, why don't the people who design the future jets try designing the shape a little bit like a ufo instead of make the...
  31. O

    Why do you aerospace engineers have such a hard time making spacecraft?

    isnt possible to make cost efficient spacecraft by putting multiple types of rockets on a ship which can then alternate rocket engine at different levels of the atmosphere and eventually escape into space?
  32. K

    Spacecraft in circular orbit

    Homework Statement A spacecraft of mass 1000 kg is in an elliptical orbit about the earth. At point A the spacecraft is at a distance of 1.2 x 10^7 meters form the center of the Earth and its velocity ( 7.1 x 10^3 m/s) is perpendicular to the line connecting the center of the Earth to the...
  33. H

    Naked singularity can actually move the spacecraft in past?

    Naked singularity can actually move the spacecraft in past? A singularity is a place where the laws of physics break down. So if singularities can interact with the outside Universe, then anything is possible. For instance, it would be possible to send a spacecraft round such a naked...
  34. kreil

    Calculate the speed of the spacecraft

    Homework Statement A spacecraft with a proper length of 300m takes 0.75E-6s to pass an Earth observer. Calculate the speed of the spacecraft as measured by the Earth observer. The Attempt at a Solution I'm not sure how to get this, when you plug in those numbers you get 4E8m/s...
  35. B

    Pressure Variation on spacecraft

    Homework Statement Hey guys, I'm helping my girlfriend who is in a 101 physics class...ha, I've taken enough engineering physics, and I guess I can't figure this one out. I'm thinking too much into it, and can't even understand the question(what its asking). Is there a pressure...
  36. W

    Slingshots for Increased Spacecraft Speed

    I have always wondered how passing into and out of a planet's gravitational field would result in a net gain in velocity. http://pluto.jhuapl.edu/mission/whereis_nh.php" is an example: the New Horizons Jupiter/Pluto probe using Jupiter to get 9000 km/hr speed increase. It seems to me that...
  37. D

    Relativity : SpaceCraft Qns

    Homework Statement An enemy spaceship moves past the Earth with a speed of 0.8 c. The captain orders the spaceship weapons department to blast the Earth with pulsed laser photons every 10 seconds. For the observers on Earth who see the flashes, what is the time interval they measure...
  38. P

    Why Heat Shields are Necessary for Crewed Spacecraft Re-Entry

    Homework Statement Crewed spacecraft are equipped with heat shields for protection when they re-enter the Earth's atomsphere. Why is this necessary? Homework Equations none The Attempt at a Solution Because upon reentering, the speeds can get so high that the outside of the...
  39. W

    Speed of spacecraft (gravitational force)

    An unmanned spacecraft is in a circular orbit around the moon, observing the lunar surface from an altitude of 43.0 km (see Appendix F). To the dismay of scientists on earth, an electrical fault causes an on-board thruster to fire, decreasing the speed of the spacecraft by 20.0 m/s. If...
  40. DaveC426913

    Help finding a spacecraft pic

    Hi. I'm looking for a pic of a spacecraft for personal use. (Likely fictional, but I"m not above PhotoChopping.) I've googled for it, but not much luck. Looking for something manned, interplanetary, early 21st century, post-Apollo. Kind of like this...
  41. Z

    Spacecraft Voyager 2 collision

    Spacecraft Voyager 2 (of mass m and speed v relative to the Sun) approaches the planet Jupiter (of mass M and speed V relative to the Sun) as shown in Fig. 10-60. The spacecraft rounds the planet and departs in the opposite direction. What is its speed, relative to the Sun, after this...
  42. D

    How Fast is the Alien Spacecraft Flying Overhead?

    hey i just need a lil help with this question An alien spacecraft is flying overhead at a great distance as you stand in your backyard. Yyou see a bright signal light in the spaceship blink on for 190.0 ms. The commander of the spacecraft measures that the signal is on for 12.0 ms...
  43. P

    Time dilation experiments with spacecraft

    I assume this has been done, but I have not seen any papers on it. For example, with the Voyagers traveling at however-many-tens-of-thousands-of-mph with respect to us, we should be able to measure the slower tick of their internal clocks (e.g., slower signalling). Perhaps this hasn't been...
  44. D

    Spacecraft collision - angular momemtum

    Identical spacecraft s A and B each of mass m are orbiting the Earth in different orbits...they both have the same perigee and at t=0 spacecraft A hits spacecraft B from behind before impact speed of A was V[a] and B was V and both a distance R from the centre of the earth After the...
  45. C

    Spacecraft Traveling Past Space Station: Length and Radio Signal Timing

    A spacecraft (Lo = 80 m) travels past a space station at speed 0.7c. Its radio receiver is on the tip of its nose. The space station sends a radio signal the instant the tail of the spacecraft passes the space station. (a) What is the length of the spacecraft in the reference frame...
  46. A

    Spacecraft altitude and orbit problem

    A spacecraft (with its cargo, a satellite) is circling the Earth at a constant speed and an altitude of 600km. The combined mass of the craft and the satellite is 1.20×10^5 kg (kilograms). At phi = 0, the captain ejects the 1.10×10^4 kg satellite out the back. The speed of the satellite...
  47. R

    Calculating Gas Mass for Spacecraft Course Change

    Hello I can't solve this one, can anyone steer me in the right direction. A 7600-kg space probe is traveling through space at 120 m/s. Mission control determines that a change in course of 30.0° is necessary and instructs the probe to fire rockets perpendicular to its present direction of...
  48. J

    Spacecraft Attitude Control Simulation

    I'm building a spacecraft attitude control simulation and I'm looking for some references to help me build a realistic mathematical model. Could someone please help me? I'm testing an AI library I built and that is requiring a lot of research in itself. Thanks for your time! Jeff
  49. Astronuc

    Space propulsion breakthrough: new spacecraft ion engine tested

    http://www.physorg.com/news9786.html :smile:
  50. C

    Time Dilation spacecraft watches

    I have the attached equation but when I plug it, I don't get the same answer as in the back of the book... Here is the question Two observers, A on earth, B in a spacecraft whose speed is 2.0X10^8 m/s both set their watches to the same time, when the ship is abreast the earth. How...
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