Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

B What can be used to propel something in space without fuel?

Tags:
  1. Aug 11, 2018 #1
    To specify, by fuel I mean fossil, nuclear, chemical and pressurized air. Want to build and design a satellite for my daughter with a camera in it (goPro) with an antenna to be able to view anytime she likes. Want to do a hexagonal approach with solar cells only for power. Want to power the gopro and a GPS locator so she will always know where it is when she wants to find it. Just trying to figure a way to move it so camera can be moved to different directions without using two different 360 degree cameras.
     
  2. jcsd
  3. Aug 11, 2018 #2

    phinds

    User Avatar
    Gold Member

    How do you plan on getting it into space in the first place? Are you asking how to do THAT without any such fuels or just how to maneuver it? Are you familiar with Newton's laws?
     
  4. Aug 11, 2018 #3

    Bandersnatch

    User Avatar
    Science Advisor

    You just want to rotate the camera so that it points in different directions? Then use reaction wheels.

    If I may ask, how do you intend to get the satellite into orbit?
     
  5. Aug 11, 2018 #4
    Getting it to space is going to be the last thing to work on. My focus is on sustainability and manueverability while up there. After working the project on this level I will be working on a way to communicate with it via smartphone to view camera and locate it while it's up there. In my opinion I have work out the electronic and electric side of it before working out getting it there. If it doesn't work then there is no reason to fire it up there. My goal is to have something that is small enough to hold in a hand.

    I am familiar with Newtons Law's.

    I hve never heard of reaction wheels. Definitely will research those.
     
  6. Aug 11, 2018 #5

    anorlunda

    Staff: Mentor

    Just to clarify your use of the word propel. To aim a camera means rotation, not propulsion. Reactions wheels can help you rotate, but not to propel the satellite to another orbit or to the moon.

    Communications to the ground may be more difficult than rotation. A satellite can't use WIFI, or Bluetooth, or cell phone towers.
     
  7. Aug 11, 2018 #6

    CWatters

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    I would start by researching what people send up under balloons. That's been done many times.
     
  8. Aug 11, 2018 #7

    berkeman

    User Avatar

    Staff: Mentor

  9. Aug 11, 2018 #8

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    There's no shame in doing what nearly everyone does and hitch a ride on a commercial rocket launch. That would cost around $5,000 per kg for a Low Earth Orbit. A google search would confirm that ballpark figure.
    It's not clear whether this is a 'thought' project or a practical 'part project' but there are aspects of such a project that you could make for your daughter. You can explain to her than there are no satellite projects that are undertaken entirely by a single organisation but that you would be limiting your part in the project to stuff that you can actually achieve.
    You could make a working model that uses readily available PV panels and a home brewed comms system, working on legal amateur frequencies. One problem that will soon reveal itself will be the misbehaviour of ordinary PC systems. You won't be able to 'turn it off and on again' when it starts to play up so you would need to look into 'fault tolerant systems' that recognise when they are going wrong and fix the problem themselves. All satellite systems need to be fault tolerant. The simpler the better.
     
  10. Aug 11, 2018 #9

    Vanadium 50

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor
    2017 Award

    Not a good idea. You need to understand the constraints about getting it into space during the design phase. Otherwise it's highly unlikely that what you design will be flyable.
     
  11. Aug 11, 2018 #10

    phinds

    User Avatar
    Gold Member

    SERIOUSLY ??? Vanadium is practicing understatement today. Unless you know exactly how you are going to get into space and what the constraints are your device likely won't get there and likely won't work, and at best likely won't continue to work, if it does get there.
     
  12. Aug 11, 2018 #11

    ZapperZ

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    How long do you think your camera will last before it is unusable due to radiation damage?

    Zz.
     
  13. Aug 11, 2018 #12

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    I really don't think we should be treating this as a serious proposition - just a valuable bit of whimsy that can teach a young student about the problems of space flight.
     
  14. Aug 11, 2018 #13

    davenn

    User Avatar
    Science Advisor
    Gold Member
    2017 Award


    ohhh and I'm pretty sure your will find that GPS doesn't work for space based locations. It isn't for finding orbital location

    For finding locations of orbiting objects, it's orbital parameters of the satellite need to be known and their ever changing values kept track of
     
  15. Aug 11, 2018 #14

    davenn

    User Avatar
    Science Advisor
    Gold Member
    2017 Award


    but he sounds so very serious :wink:
     
  16. Aug 11, 2018 #15

    berkeman

    User Avatar

    Staff: Mentor

    I'm calling troll until @Andrew broome sends me a message to convince me otherwise. What a waste of time. Thanks to everybody for trying to help out if he were sincere in his posts.

    Thread locked.
     
  17. Aug 17, 2018 #16

    PeterDonis

    Staff: Mentor

    Just as a correction since this thread is still visible: the GPS system itself is perfectly capable of being used to obtain position fixes in space. See, for example, this page from NASA's website:

    https://www.nasa.gov/directorates/heo/scan/communications/policy/GPS_Utilization.html

    Many ground-based receivers won't report altitude and won't work properly at altitudes too far from mean sea level, but that's a limitation of the receivers, not of GPS.
     
  18. Aug 17, 2018 #17

    anorlunda

    Staff: Mentor

    Yes, but isn't the problem that the transmitters are not omnidirectional, they are aimed down at the surface.
     
  19. Aug 17, 2018 #18

    PeterDonis

    Staff: Mentor

    Yes, you're right, they are, which means you need more sophisticated and sensitive receivers at higher altitudes. This page describes potential usage out to geosynchronous orbit:

    http://insidegnss.com/navigating-in-space/

    The article also notes that for orbits lower than 3000 km altitude, GPS works basically the same as for ground-based usage; that's already enough to cover a lot of satellite orbits.

    Another issue I had in mind that limits the altitudes at which many ground-based receivers can work is that the algorithm for finding a GPS fix does not give a single unique location; there are usually at least two possible solutions. But if you know your receiver is within some fairly narrow range of altitudes, that rules out all but one solution, which simplifies the receiver's code.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook