There's much to be said for the economy of restricted-capability solutions such as a Soyuz. With that in mind, how would NASA have accomplished the range of missions that you (correctly) ascribe to the Space Shuttle? By building a separate vehicle for each need? What would that cost? By not performing the mission? Yes, that would save money. By using robotic everything? (a science fiction pipe dream if anything, that...) The Space Shuttle was expensive to build, expensive to maintain, expensive to launch... but where's the alternative if you want to carry 65,000 pounds to orbit today, and a SpaceLab tomorrow? (Well, not tomorrow... about a month from the previous launch.)
The Shuttle designers had vision and guts: no one had any experience with entering the atmosphere at what? Mach 25?, and controlling by a mixture of jets and aero surfaces. No one had any experience with a lot of Shuttle technology, but NASA managed it anyway. What did the Soviets do along those lines? They built the Shuttleski, I forget what they called their clone, and flew it once. What a shame now that we have to hitch rides in a Soyez to reach our own Space Station.
NASA's manned space flight costs were so high mainly due to the reliance on the space shuttle program for the last 30 years.
The space shuttle was by far the largest and most complex thing ever put into Earth orbit. Why? Because it was designed to be multi-purpose and reusable. It had to carry a crew of up to 8. It had to be large enough to carry the Hubble Space Telescope, ISS modules, and interplanetary probes into earth orbit. It had to serve a dual role as a military launch vehicle, carrying large military/defense satellites and operating from two launch facilities and two landing facilities. It had to be able to maneuver to different orbits to perform its multitude of missions. Numerous repairs and retro-fits were required to the same aging spacecraft over 30 years.
In contrast, the Russian Soyuz spacecraft settled into a much more focused mission: to carry a small number of men and supplies to earth orbit, typically to MIR or the ISS. Soyuz is cheap, reliable, and safe. A few cosmonauts died in the earliest versions of the Soyuz, but the Russians continually improved it, to the point where there hasn't been a fatal accident in 40 years. Upgrades and redesign can be implemented on new spacecraft, rather than retrofitted as with the shuttle. Soyuz is a government-run program and faces the same risk-reduction pressures as in NASA, but a focused mission allowed it to achiev a record as the most safe yet most cost-effective manned spacecraft ever.
The private ventures potentially will operate less expensively than NASA not mainly because they are "private", but because their missions are also much more limited in scope.
I am hopeful that private space industry and the Russians will remind NASA and all of us that more focused missions and more focused space hardware is needed for many of the routine tasks of space flight.
Obviously, submarines and space vehicles each have their own distinct risks, failure modes, critical modes, and more--each is quite risky in its own way. And there is a big difference in real-time connectivity and tracking, too, which can affect what we know about them.
"The ocean is not all that benign, Bert..."
Am well aware of that. Just making the popint that long distance space travel is far worse.
For instance, submarines are supposed to operate always with some amount of buoyancy, so that if the engines fail, they slowly float to the surface. Can a space craft do that?
I thought I was qualifying my answers carefully enough to show that we're not talking about safe vs hostile, we're talking about two different levels of hostile.
"... but I don't know how anyone gets out of a sub at 800'."
If you haven't taken on too much water, or if your air scrubbers have not been OOC for too long, or whatever mishap is not overly catastropic, you simply blow all ballast tanks. And in minutes, you're bobbing on the safe surface.
If on the other hand you are in a space vessel in orbit around Mars, and your air scrubbers fail completely, or something breaks in the ship that your tiny handful of crew cannot fix, you are SOL.
Even just a bad toothache becomes a problem in long distance space travel. On a sub, worst comes to worst, you surface the sub and evacuate the crewman via helo. No big deal.
Bert, Trident subs have listed test depths of "only" twice their length because they are 170 m long! At 800' you have pretty serious pressure and leakage considerations. Plus, these machines support their crews for months, if not years. If you ditched the armament, you'd have supplies until the crew went totally crazy. Plus, they carry their own power supplies, something that orbital craft don't do: they rely on solar power (decreasingly useful as you head out in the solar system.) No, I think Electric Boat Division of GD could do a pretty good job on a deep solar system vehicle.
Hostile environment: if the Space Station gets a 1" diameter leak, it loses half it's atmosphere in about 24 hours. No astronaut sleeps through the alarms that long. A 4" hole will bring you to half atmosphere in about 6 hours, I seem to recall. Not a good situation, but not a "we're going to die right now" sort of thing. What happens on a Trident sub if a 4" hole opens up at 800'? Anyone want to tell me?
As far as "no room for error" what does that mean? You know perfectly well that things fail, and that failures must be handled. On spacecraft, either fault tolerant design (as in pressure vessels) or fault containment techniques (redundancy) are used extensively, somethings that causes bonafide increases in cost. Subs have the same problem: failures occur, and you have to be able to do something about it besides dying or aborting the mission.
No, sorry; I think submarines hang out in at least as bad an environment as low earth orbit... the Space Station provides a get-away capsule (if you are brave enough to use it) but I don't know how anyone gets out of a sub at 800'.
If I recall correctly, the Chinese have announced plans to go to the moon and then perhaps mine for Helium3, as have the Russians.
When we were racing the Soviets to the moon in the 60's, we did it better and faster, but certainly not cheaper. Unfortunately, we don't seem to have the same deep pockets that we did back then. Or, the pockets may be deep, but they have holes and all of the money fell out.
Not just paperwork, but exacting specifications that demand a product not available on the commercial market.
This is changing, with the push for COTS, but it certainly has been the case in the past. So this very exacting toilet seat, if you want to use that hypothetical example, would only be sold in comparatively tiny quantities. And the unit cost, naturally, goes way up.
Well, first off, the only submersibles that can actually reach deep down to the ocean floor are very tiny craft, only capable of short duration missions. Nothing like what it would take to reach Mars, for example, which would be at least an 18-month journey, with no hope for a quick mission abort, as a submersible can do.
The numerous submarines we do build, believe it or not, can hardly go any deeper than twice their length. Check it out. And even they can abort their dives, if need be (unless some catastrophic accident happens).
So the two are not comparable. Manned space missions, I mean the ones beyond the space station, are really going to deal with hostile environments and no room for error.
NASA's Orion Flight Software Production Systems Manager Darrel G. Raines joins Planet Analog Editor Steve Taranovich and Embedded.com Editor Max Maxfield to talk about embedded flight software used in Orion Spacecraft, part of NASA's Mars mission. Live radio show and live chat. Get your questions ready.
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