Will there be orbital "space planes" in the near future?

[spacester]

I came to a surprising conclusion when doing a little research on the hybrid engine to answer the question of emissions from it. I didn't find anything definitive.<br /><br />But if you look at the HTPB molecule, you see nothing but C and H atoms. No sulphur or other nasties.<br /><br />So no big black cloud of smoke from burning rubber.<br /><br />Burning with the nitrous, maybe you'd get same nasties with the Nitrogen atoms, but that's about it. It would seem that even with incomplete combustion there is no big issue.<br /><br />But as said, nothing definitive was found on the question. <div class="Discussion_UserSignature"> </div>

 

[halman]

By confining the second stage, or orbiter, to liquid hydrogen and liquid oxygen, upper atmosphere pollution would be limited to water. The carrier wing would burn kerosene and atmospheric oxygen, and most modern turbofanjets are extremely efficient, which means very little pollution. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>