[zargath]

Im a huge SpaceX fan, but Blueorigin's New Shepard does seem more robust. Maybe just because its a smaller and more thick rocket, but somehow by not being as spectacular it makes space travel more "normal" as we all hope it someday will become.

[ceejayoz]

> Im a huge SpaceX fan, but Blueorigin's New Shepard does seem more robust.

That's a little like comparing a F1 racer to a wheelbarrow, isn't it? Both are immensely useful for specific things, and would fail miserably if applied to the other's thing. New Shepard is cool, and I'd love to hop in it some day, but it's doing a little up-and-down suborbital hop. The two launchers have totally different purposes, and are constructed in entirely different ways as a result.

[nickik]

Also, the BE-3 engine will be very useful and seeing how stable it performs is very good. It will fly on the upper stage of New Glenn (BE-3U). There are other projects that are suspected to use the BE-3.

[nordsieck]

> more thick rocket

This is almost entirely driven by the fuel used - liquid methane is about 6.5 times more dense than liquid hydrogen.

[dotancohen]

With the super-chilled densified propellants, the Falcon 9 would be better off shorter and thicker to reduce surface area. However, the Falcon 9 must be ground-transported, which is why it has the same diameter restriction that the SST's SRBs had: 3.6 meter.

With no restriction on ground transport, the New Shepard can be as thick as engineering deems is necessary.

[nordsieck]

> Falcon 9 would be better off shorter and thicker to reduce surface area

Can you show me some references to this?

My understanding is that there is a tension between two goals.

The first goal is to maximize aerodynamic efficiency, which means minimizing frontal surface area.

The second goal is to minimize non-fuel weight, which means minimizing the surface area to volume ratio.

It's not obvious to me that the Falcon 9 would be better off shorter and wider.

[dotancohen]

> Can you show me some references to this?

Lots of people have done the calculations. Poke around the Reddit Spacex forum and NSF forums, lots of discussions there.

> The first goal is to maximize aerodynamic efficiency, which means minimizing frontal surface area.

The fairing is already wider than the first or upper stages, so increasing those stages to the fairing's width would actually improve the aerodynamics.

[grondilu]

> Blueorigin's New Shepard does seem more robust.

Well, NS was designed for re-usability from the start, while F9 had only re-usability plugged-in later as an experimental feature. SpaceX's priority was to get to orbit ASAP in order to be commercially viable.

I bet BFR will look much studier than F9.