Exploration or explorations

I would do this, actually:

Several methods of space exploration have been proposed.

Thanks for the your great reply.

Can you help me with a similar problem? Are they both OK (only one wireless sysytem and one cable system were used) or is there a better way to write it?

We did the experiment with both cable and wireless signal transmission systems.

We did the experiment with both a cable and a wireless signal transmission system.

Thanks

Hello, David. I would do this, but it is still not clear, perhaps. Did you use both systems in a single experiment or do one experiment with one system and another experiment with the other?

We performed the experiment with both a cable system and a wireless signal transmission system.

Hello Again

Thanks very much again for your help.

We did the experiment twice. Once with a cable system and once with wireless signal transmission system.

Does that make a difference to your suggestion?

Thanks again

David

Yes, frankly, I think it needs to be made more clear (if the accompanying text does not do so):

We performed the experiment twice, once with a cable system and once with a wireless signal transmission system.

Thanks again for your reply. You have been a great help. Your sentence clealy says what I wanted to say.

Thanks a lot

David