1. Dry scrubber using coke as the adsorbent agent, with or without precooling, followed by a bag filter

2. Dry scrubber using coke as the adsorbent agent and with or without precooling, followed by a bag filter

3. On the other hand, LACE-like precooled airbreathing designs such as the Skylon spaceplane (and ATREX) which transition to rocket thrust at rather lower speeds (Mach 5.5) do seem to give, on paper at least, an improved orbital mass fraction over pure rockets (even multistage rockets) sufficiently to hold out the possibility of full reusability with better payload fraction.