NASA, Congress Reach Accord On Commercial Crew Program

New Sheperd in all regards hits me as pure naivete. For example, using HTP as an oxidizer. I'm well familiar with the logic here. "Oh, sure, it's got less ISP than LOX, but it's SIMPLER! And ISP isn't everything! We'll go simple and cheap, and get a simple, cheap craft!"

And that logic is wrong.

First off, the lesser issue: ISP may not be everything, but it's huge. The scaling factor for having bad ISP is pretty massive, and your other costs will add up quickly as your craft balloons, everything from your transport costs to your launch liability. People who just discount it like that do a big disservice to themselves.

But the bigger issue: HTP is *not* simpler than LOX. It's a giant pain in the arse. It's explosive, which requires that you have sterile, defect-free tanks and systems with very specific materials requirements and purity constantly maintained. Its explosivity can be greatly reduced by the presence of stabilizers, but therein lies the other problem: the more stable you make it, the less reactive it becomes, and if you're using any sort of catalyst pack (which themselves are full of problems), you tend to clog it. Peroxide vapors from even stabilized HTP are explosive. Stored HTP can become less stable over time, and leaks can be catastrophic (as many people, perhaps most famously in recent years the crew of the Kursk, have learned). Heat can set it off. It's difficult and dangerous to concentrate in terms of oxidizer production. It's illegal to ship in tanker trucks due to its hazardous nature. Etc.

People think about household H2O2 solutions and just picture a more powerful version of that. That is not what HTP is like. The Germans and later the US went with HTP a lot early in their rocketry programs. The fact that its usage became greatly curtailed over time should speak volumes.

Basically, HTP is just reinventing a bad wheel. There's one little explored fuel combination that I'd like to see more focus on, personally: LOX/Propane. Propane is of course widely available, cheap, and easy to transport. It's higher ISP than RP1 (LOX/RP1 being a common propellant combination), but the downside when you first look at it in a table is it's much lower density. BUT, at the same temperature as your LOX - aka, they can share a common bulkhead without insulative separation, reducing system mass -- it's actually quite dense. LOX/Propane is also easier to vaporize and ignite.

brandon marshall iditarod nfl free agents 2012 encyclopedia brittanica nfl free agency jonbenet ramsey jason campbell