INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Nuclear Pulse Drive Spacecraft

Nuclear Pulse Drive Spacecraft

(OP)
Dear Engineering.com Folks;

I am a free-lance author and researcher in the theoretical field of relativistic astronautics.

I have a question regarding applications similar to that of the original Project Orion nuclear pulse driven spacecraft research.

Essentially, I am looking for the best current materials for springs that would handle a compression force ranging from about 10 EXP 9 Newtons to about 10 EXP 12 Newtons to drive a space-craft with a time averaged acceleration of about 0.1 m/(s EXP 2) to about 10 m/(s EXP 2).

I am considering cases where the ambient temperature of the spring environment is near 2.725 K such as that of the CMBR and cases where the environment of the spring is held more or less at room temperature.

Any information on compression heating of the spring material would be of help.

Alternatively, I would also appreciate guidance on the use of arrays of numerous smaller springs where an array as a whole would handle a compression force ranging from about 10 EXP 9 Newtons to about 10 EXP 12 Newtons to drive a space-craft with a time averaged acceleration of about 0.1 m/(s EXP 2) to about 10 m/(s EXP 2).

Thanks for your consideration.

Jim

RE: Nuclear Pulse Drive Spacecraft

A desired spring rate would help. 109–1012 N...Intuitively a torsion spring doesn't sound all that applicable (my intuition is not very reliable). Something like a scaled up carbon leaf spring might work. An effective material modulus between 60 GPa and 540 GPa is achievable, with strength of about 1000 MPa and 2000 MPa respectively (double that if highly stressed material could be about 180 GPa). Heating shouldn't be a great problem as long as the frequency of deformation is less than 1 Hz (I assume that the environment is worse than an in-atmosphere due to the only heat removal being radiation). You should be able to sustain stresses of about half or maybe three-quarters that quoted repeatedly with a frequency of <5 or 10 Hz (a temperature rise of about 50°C might take place—that's a guess based on experience of terrestrial testing). Carbon-polymer is happy to contain liquid hydrogen (-253°C/20 K) and an upper limit of about 200 or maybe 300°C. Not entirely sure what a lower limit of -270°C might do but there shouldn't be any nasty surprises. Satellites and deep space probes have had to handle that temperature.

RE: Nuclear Pulse Drive Spacecraft

(OP)
Dear RPstress (Aerospace);

Thanks very much for the reply.

I am about to search for info on the carbon springs you had mentioned. My best guess is that I would want to have the pulse drive at a frequency below 1 Hz as you suggested.

Also, I think I may have red-flagged my own post and/or reply by accident since I noticed the red flag icon show up after I clicked on a menu option or something by mistake.

Note that I have problems with mal-ware attacks so perhaps I may need to chance my pass-word.

Regardless, I will do some more searching on the parameters you suggested.

I ran some Fmax numbers for ASTM A228 and achieved values ranging from about 300 million N to 30 billion N but where the spring weight on Earth's surface was only about 1 percent of the max compression force.

However, sounds like the carbon material you suggested is a better one to work with.

Best Regards;

Jim

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close