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. J

    B Can Unequal Masses in a Tethered Spacecraft Simulate Gravity Effectively?

    In discussions about simulating gravity in a spaceship by the use of tethered masses revolving around a common centre, the assumption appears to be that these masses must be equal. Would instabilities occur were this not the case? Or would the problem go away simply by placing the hub at an...
  2. Victor Aires

    Designing a Thermal Protection System for Spacecraft: Where to Begin?

    Hello, I want to learn how to design a spacecraft's thermal protection system. But I don't know where to start. Someone can help me?
  3. D

    B Energy production that converts Hydrogen to Iron?

    Suppose a craft derived its energy from fusion— converting Hydrogen into Iron… If it started with a kilo of Hydrogen, how much mass of Iron would it have at the end and how much energy would be extracted?
  4. D

    I Spacecraft With Solar Mass Energy Equivalent Kinetic Energy

    Suppose in a different star system, a space shuttle sized spacecraft acquired a solar mass energy equivalent amount of kinetic energy, then passed through our solar system. While it was passing through the solar system would the craft’s gravitational effects be more similar to the space shuttle...
  5. K

    Engineering Calculate angle between spacecraft & Sun vectors

    Hi, so I have no clue how to solve this problem but I started off by rewriting the issue as a dot product to find the angle. So; cos(θ)= RSC⋅RSun / ∣RSC∣⋅∣RSun∣ Where Rsc = space crafts position vector. Rsun is the Suns position vector. ∣RSC∣ is the length of the spacecrafts position...
  6. klwong

    I Moving Spacecraft propellent less?

    Assuming there are four robot inside a stationary spacecraft (mass 2 ton) , robot A has an electric gun that can shoot iron balls weighing 1kg at a speed of 8m/s. These balls collide with red balls at a 45-degree angle in a two-dimensional elastic collision. Each ball has a mass of 1kg. The red...
  7. osaplabs_sja

    A Can any thin materials protect a Mars spacecraft from gamma rays?

    Astronauts heading towards Mars (and hopefully return) will need protection against the harmful effects of gamma rays in space for this long trip. Apparently, much shorter trips have not caused enough bodily harm to be of much concern. However, a 6-month or longer trip might be a real problem. I...
  8. davenn

    Stargazing ATLAS observations of the DART spacecraft impact at Didymos

    Astronomers with the ATLAS project also chronicled the event. Short for Asteroid Terrestrial-impact Last Alert System, ATLAS is an asteroid impact early warning system based in Hawaii and funded by NASA. “ATLAS observations of the DART spacecraft at Didymos” exclaimed ATLAS in a tweet. A...
  9. BarChen

    Become a Propulsion Engineer - Learn to Work with Rockets & Spacecraft

    Hi guys, I'm about to start my degree in a few months and I know what field I want to major in but I don't know what track I should take. In the future I want to work with rockets and spacecraft engines, I want to help develop the new generation. Correct me if I'm wrong but it's called a...
  10. T

    I Voyager Spacecraft beginning to Power Down

    An interesting article on some of the history of, and discoveries by, the 44+ year old Voyager spacecraft s. The bean counters originally planned a 4 year mission for Voyagers 1&2. However, the scientists and engineers involved saw a golden opportunity that wouldn't repeat for another 176...
  11. kolleamm

    B Mini spacecraft to Alpha Centauri

    The idea for the mission is that if we built a spacecraft small enough, we could push it with laser(s) to Alpha Centuri within a resonable amount of time, and once there it could send us back images of the star/planets. My question is, would a tiny spacecraft even able to transmit the data...
  12. S

    Conservation of momentum of spacecraft and asteroid

    By "DART will have a relative speed of 6250 ms-1 when it collides with the asteroid", I assume it is the relative speed of the DART with respect to the asteroid. Using that assumption, I can answer question (a) For question (b), I don't understand the solution from the teacher. He did it like...
  13. J

    Detection of spacecraft at large distances

    According to NASA the Space Shuttle required 12 GW to get it off the launch pad. So if a hypothetical rocket at the Second Lagrange Point (where the JWT is heading for right now) was producing the same amount of watts, all other things being equal, how far away in space could this output be...
  14. LCSphysicist

    Special relativity and simultaneity: Spacecraft and Target

    I made an exercise whose question is like that: A spacecraft moves with speed v at the axis x. There are two target at the axis x, in which the distance between them is L at the ground frame. Suppose that the spacecraft shoot the target simultaneously when it passes by the target. A|so...
  15. A

    I Questions about the Voyager spacecraft

    Is there a possibility of a celestial body colliding with the Voyager spacecraft ? Is there an alternative to the Voyager that runs faster and faster? For example, at a speed of 100 kilometers per second
  16. anorlunda

    Lucy spacecraft and James Webb space telescope

    Apparently, one of the solar arrays on the Lucy spacecraft failed to fully deploy. https://scitechdaily.com/nasas-lucy-stable-in-cruise-mode-problematic-solar-array-is-75-to-95-deployed/ The fault may not be fatal. They may have enough solar power to complete the mission. At the same time...
  17. alan123hk

    Interstellar Spacecraft Voyager 1

    The interstellar spacecraft Voyager 1 was launched in 1977 and left the solar system to reach the endless interstellar space in 2012. It is now 2021. Voyager 1 has been sailing in space for 44 years. Why does it still have energy to send electromagnetic signals back to the earth? What does...
  18. TonyCross

    Spacecraft - Interplanetary Designs

    Hi, Does anyone by any chance have a link to a blueprint-design for an interplanetary spacecraft , either existing or planned. My reason for asking is I am simulating various aspects of the propulsion and reaction control systems. I would like to use an existing design to model then experiment...
  19. S

    My arXiv preprint on a crewed interstellar spacecraft

    Hi everybody, I would like to share with you a crewed interstellar spacecraft which I have designed and called Solar One. It employs a combination of 3 propulsion methods: nuclear fusion, beam-powered propulsion , and photon propulsion. Basically, several compact fusion reactors power a...
  20. E

    Can Sci-Fi Spacecraft Achieve Stable Orbit with Plasma Technology?

    Hi. I'm not expert in physics. Recently I have written an article how a spacecraft will remain in orbit forever. However need review if there is any mistake using formulas or the term escape velocity. Here is it, Layman question: So what will happen if we use sci-fi spacecraft to takeoff...
  21. MUZE

    Airship on Earth but a reentry glider on Mars

    Could a hybrid airship like spacecraft ever so slowly shed speed using Mars' atmosphere while remaining low orbit while buoyant enough to serve as a glider?
  22. Like Tony Stark

    Angular Momentum Conservation in Spacecraft Orbits

    Tell me if I'm right: A) Angular momentum is conserved because there are no external torques. Linear momentum isn't conserved because gravity is acting on the spacecraft . Mechanical energy isn't conserved because it has to change between different orbits. B) Parabolic orbit...
  23. T

    B New Storms on Jupiter, by Juno spacecraft

    https://www.space.com/nasa-juno-dodges-death-jupiter-polar-storm.html Includes a video.
  24. B

    Fastest Nonmanned Spacecraft Possible?

    So what I am really asking is... what is the highest acceleration missile we could make for space that would not crush itself under it's own weight? Assume any engine thrust level is truly possible, we are only limited by material constraints that would crush the missile under the weight of...
  25. DanielGutierrez

    Finding out how the different spacecrafts were made

    Homework Statement: Actually I'm in my last year of Material Engineer, and I have been asked to choose a topic for studying the evolution of the materials involved. With some emphasis on surface. Homework Equations: --- Hey everyone, I'm in my last year of Material Engineer, and I have been...
  26. jisbon

    Calculate the time for a spacecraft to arrive at Mars (No Kepler's law)

    So I've seen many similar questions like this on the internet, but they all involve using Kepler's law, which is not in my syllabus in my case. However, they do give me the mass of the Sun. which I assume involves gravitational force/field/circular motion? The question also gave me a hint that I...
  27. trurle

    Braking spacecraft in a snow-filled tank?

    Reading recently a Russian MOD aerospace journal, i stumbled upon (pretty unrealistic) scheme to hard-land payloads (metal ingots) on moon. It involve catching 1.7 km/s slugs with the pipe filled by regolith or water, and even more hardcore option of digging up the payloads embedded in the...
  28. G

    What are the likely first forms of relativistic spacecraft propulsion?

    I've been interested in relativistic spacecraft since news of the Breakthrough Starshot project announcement a few years ago. Breakthrough Starshot's method of laser propulsion still has many technical hurdles needed to be crossed. So I'm wondering what you guys think the first forms of...
  29. D

    An astronaut is piloting her spacecraft

    Find acceleration vi=20.0 m/s[E] vf= 0 t= 12 s a= ? 0 =20+ a(12) 0-20 = a(12) -20/12=a -1.7m/s2 [E]= a textbook says it's 1.7m/s [W] Is it because when velocity decreases, it increases west (opposite direction)? Is -1.7m [E] same as 1.7m [W]??
  30. solarcat

    Calculating Work for Launching a Spacecraft to a Great Distance from Earth

    Homework Statement Say you're launching a spacecraft of mass m from the surface of the Earth (mass Me and radius re) to a low height h (h is much smaller than r, so h is essentially negligible). How much work is required to move the spaceship from its low orbit to a great distance from earth...
  31. MasterJgon

    Flying saucer. Picture, project of a spacecraft

    Principle, scheme, images of a flying saucer. Reusable spaceship of the future. Spaceship with a solar sail.
  32. Halit

    Artificial gravity in a spacecraft

    Homework Statement https://i.hizliresim.com/Bzp05M.jpg " spacecraft " Now you're in other space.No gravity at all.You 're going to make your own artifical gravity R = 100m Quest 1-) With which angular velocity, g is equal to 10 (g = 10) 2-)Can you walk from b to a? Why is that 3-)Can you...
  33. Andreza Carvalho

    NASA NASA Parker Solar spacecraft question

    How will the NASA spacecraft resist when approaching the Sun?
  34. H

    I Cooling the Parker Solar Probe

    This probe is designed to fly closer than 4 million miles from the sun's 'surface'. Is it possible in principle to cool the spacecraft 's inner facing surface by transferring heat to a cooler part and then radiating it into space from the far surface? I don't think it is equipped with such tech...
  35. 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...
  36. T

    Characteristic equation in terms of the Laplace operator

    Homework Statement The stability of a spinning body may be explored by using equation (3.40), with no torque components present. It will be assumed here that the spin is about the z -axis and has a rate ωZ = S. Homework Equations $$I_{xx}\dot{ω} - (I_{yy}-I_{zz})Sω_y = 0$$ $$I_{yy}\dot{y} -...
  37. A

    Could a spacecraft refuel from the atmosphere?

    https://phys.org/news/2018-03-world-first-air-breathing-electric-thruster.html If it dipped into the atmosphere temporarily on an elliptical orbit, could the air gathered be stored for a long flight? Then maybe get more fuel from another planet's atmosphere or moon for the return trip?
  38. kolleamm

    B Launch Spacecraft to Near c Speeds: Is it Possible?

    Is it possible to spin a tiny spacecraft to near c speeds, and then have it eject from the object it's spinning on into space? I came with this idea after seeing the Starshot project that involved lasers and thought there might be a better way. What are your thoughts on this? Thanks
  39. I

    Finding the relativistic speed of a spacecraft

    Homework Statement If a spacecraft is traveling to a star which is located at a distance of 1 lightyear and it would take the spacecraft 1 year to reach the star in its own frame, how fast would the spacecraft actually fly? Also, how long would the journey take for an observer on Earth...
  40. Y

    Gravitational problem, spacecraft orbital period

    Homework Statement I need help getting started with this problem At what altitude above the surface of the Moon must a lunar module orbit in order to complete each orbit in 1 h 49 min 39 s? Homework Equations g= Gm/r^2 ? The Attempt at a Solution Not quite sure how to start or anything , any...
  41. wolram

    Anomalous accelerations in spacecraft flybys of the Earth

    The suggestion is a fifth force to counter these anomalies is this generally excepted? arXiv:1711.02875 [pdf, ps, other] Anomalous accelerations in spacecraft flybys of the Earth L. Acedo Comments: 41 pages, 11 figures (Accepted for publication in Astrophysics and Space Science) Subjects...
  42. H

    Designing a Spacecraft any tips?

    I've been working on this passion project for a couple of years now and was wondering if you guys have any tips all I can say right now is.Its lunar capable,going to carry 8-10 crew and 2 landers or cargo,reusable,and easily modifiable for Earth orbit operations.
  43. A

    Courses Want to do spacecraft propulsion R&D but love astrophysics

    I've always been fascinated with space and space travel and want to see humanity advance in that area. I've always thought the best way for me to contribute is to work in research and development for propulsion systems (which I'm interested in), however, my main passion in physics is...
  44. A

    Work, Gravitational Potential and Kinetic Energy, Spacecraft

    Hi guys. I'm new to this forum so I'm not sure if I'm posting this in the right place or correctly, but I was totally stumped on a Physics 12 question as I was studying for my exam. The question is: An explorer spacecraft is descending towards Mars using a rocket engine for braking. The...
  45. R

    I In gravitational assistance, does the mass matter?

    The spacecraft "Helios 2" (with 100 kg of mass) used the Sun to get a speed of 250.000 km/h using gravitational assistance, I want to know if the mass of the spacecraft influences the result of the speed. I mean, if the spacecraft mass 10.000 tons, the speed would be less of more?
  46. H

    Velocity of a spacecraft at relativistic speed

    Homework Statement The closest star system is about 4.3 light years away from Earth. A spacetug is able to move a cargo ship at a constant force of g=9.8N/kg times the mass of the cargo ship for many years. Starting from rest, speed up the cargo ship until you're halfway to the nearest stars...
  47. Jeremy Thomson

    Spacecraft reactor sheilding and heat radiators

    I've been watching "The Expanse" and considered, if the spaceships are some sort of fusion powered drive, why aren't they covered in radiator panels to reject all the heat from the reactor/drive system? How many square meters of radiator panels would a 20MW (thermal) fission reactor require? An...
  48. Noakhailla Hola

    Spacecraft splitting into two near a planet

    Homework Statement I am doing a MATLAB simulation for a spacecraft that splits into two near a planet, and one part enters the planet's orbit while the other part avoids the orbit. I am a bit unsure about the physics of the split. Since there is a net force due to gravity, I guess momentum is...
  49. Leyzorek

    Does Friction Affect Momentum in a Spring-Driven Spacecraft?

    Homework Statement Spacecraft, with vacuum inside, in free-fall, contains a small mass captured against a fully-compressed compression spring against one wall of the craft. Release the spring and mass. Mass is accelerated by recovering spring (elastic potential energy turning to kinetic)...
  50. D

    I Particle/planetary simulation with spacecraft

    I am building a spacecraft simulator in a realistic planetary environment. At the moment it uses very simple Newtonian equations of motion. Each object has displacement, velocity and acceleration vectors. Each time the computer does a loop: 0.1 seconds pass and in each loop each object...