Sunday, November 30, 2014

Back to the...Past?

"What's wrong with NASA? Don't they know that a capsule is soooo 1960's? And rockets? ROCKETS?!? The Space Shuttle *looked* far more advanced...and we're going back to capsules and rockets? That just proves NASA is yesterday's news!"

I can't tell you how many times I've heard that, or something very similar to that, when talking to people about the space program. And knowing the poor state of aerospace journalism in the mainstream press, one could be forgiven for harboring such an opinion. However close external appearances may suggest, though, rest assured that it's what's inside that counts.

Let's start with the ship itself - Orion. As one can see from the image to the right, Orion bears the same 'gumdrop' shape as its Apollo predecessor, though a bit larger. Orion is nearly four feet (forty-two inches, to be exact) larger in diameter than Apollo, though a tad shorter. Don't let the visual similarities fool you into thinking that they're the same inside, too. While Apollo had 218 cubic feet of habitable space, Orion sports a comparatively roomy 692 cubic feet. Of course, both pale in comparison to the Space Shuttle's spacious 2,625 cubic feet.

"A-HA! You see, the Space Shuttle *was* superior!" Well, yes...and no. If one is simply considering interior space, then yes - the Shuttle had more. That said, the Shuttle was built to be a jack-of-all-trades...and, as the old adage goes, it was a master of none. Unmanned rockets could get materiel to orbit more cheaply (and safely) than could the Shuttle. OK, so the Shuttle could repair orbiting satellites - or bring them home if on-orbit repair wasn't practical...but was that worth the massive costs to keep the program alive?

The Shuttle was forever tied to low Earth orbit (LEO). No matter what science fiction might have one believe, the Shuttle couldn't make it to the Moon (aside: why do we say 'the Moon'? We don't say 'the Mars' or 'the Saturn'. Maybe we'll tackle this another day.), or to an asteroid, or to a comet on a collision course with Earth. LEO was its home. Both Orion, and Apollo before it, only use LEO as a stepping stone to get to its ultimate destination: deep space.

So what IS the point of the ship? Is it to provide research space? Act as a truck to tote cargo to orbit? To build a space station? No. A ship's purpose is to transport its occupants - safely - from launch...to destination...to recovery. If that's the measure of a successful ship, then the 'capsule' design has a stellar record.

While we're on the subject of safety, I don't think anyone can rationally argue that placing the organic bits as far away from the exploding bits isn't the safest place. The Shuttle's placement on the side of the 'stack' was inherently unsafe, and there was no survivable abort mode while the SRBs were still firing. Even after jettisoning the boosters, any further abort modes were tricky, at best...and fatal, at worst. There was no 'Launch Abort System' (LAS) to pull the Shuttle (or crew compartment) away from disaster - the astronauts were, for better or worse, largely along for the ride. Placing the ship at the top of the stack is SIGNIFICANTLY safer than the Shuttle's side-mounted configuration. Though any abort would still be dangerous, the crew would be far more likely to survive a 'rapid, unplanned disassembly' of the launch vehicle if their ship is at the top of the stack and has an LAS.

This is old and boring...
Why, then, is there a hue and cry about NASA's return to a capsule design? Though I can't say for sure, my gut tells me that it's because it doesn't look "cool". People expect space ships to look 'futuristic'...whatever that means. The Shuttle evoked a sense of moving forward, and even though it wasn't terribly efficient, it at least looked the part. The capsule, though, looks more like a "been there, done that" design. Well, what of it? Even though there are geometric designs that could provide a constant rolling surface, we still use the same basic design for tires and wheels that have been working well for over one hundred years. If it's not broken, why fix it?

...but this is new and cool.
Moreover, people seem to be falling all over themselves with SpaceX's Dragon capsule. Why is it wonderful when SpaceX uses a tried-and-true capsule design, yet NASA is considered moribund if they do something similar? Don't misunderstand me - I'm a HUGE fan of SpaceX...I think they're on the cusp of completely upending the traditional players in the aerospace sector - but if one is going to complain about NASA's design while heaping praise on SpaceX, then they need to go look up the definition of 'hypocrite'. 

Now, if one wants to have a discussion about costs and mission, that's a completely different animal...one that we might address in the future. Until then, thanks for visiting and please join the discussion in the comments.