> With an aerospike, you have an expensive engine that you don't want to drop (because it's perfectly efficient at every altitude) but now you have to figure out how to shed the dead mass as you go.

> Personally, I've always envisioned an aerospike working well on a Space Shuttle type vehicle- the engines are kept and the fuel tanks are discarded. I'm interested to see if aerospike development comes with a change in how we see launch vehicles in the post-shuttle era that's largely dominated by disposable or VTOL-recoverable first stages.

My immediate thought on reading that first statement was also that the space shuttle had already solved that perfectly:) Is there any caveat to just strapping on disposable fuel tanks that are jettisoned as you go? Other than needing connectors and the tiny matter of completely redesigning the overall rocket, of course;)