Thoughts on the state of our space hardware
At the end of 2010 (the year, according to Arthur C. Clarke that we're supposed to be launching our second manned mission to Jupiter) NASA will retire the space shuttle fleet from active service after nearly 30 years of operation. At that point in time, we will lose our ability to effect on-orbit repairs beyond the vicinity of the Space Station. Originally billed as the vehicle which would democratize space travel, the space shuttle became an expensive boondoggle. Much of this was due to the fact that the shuttle's design was the product of engineering by compromise and committee, rather than the Apollo era's commitment to excellence and reliability in design. The Air Force dictated the dimensions of the cargo bay (big enough to fit all of their spy satellites.) Engineers transferred from the successful Titan-Centaur program insisted on using solid rocket boosters, over the prophetic objections of none other than Werner von Braun himself; those SRBs--or rather the failing O-rings in them, and a poor decision to launch in freezing weather--doomed the crew Challenger STS-51L. Though, that's not the whole story: according to telemetry, at least five of the crew aboard Challenger's final, fatal flight, were still alive after that explosion, one of them was conscious enough to activate Ronald McNair's emergency air pack as they fell for 2 minutes at terminal velocity down to the surface of the Atlantic. If the shuttle had an active crew escape option, like every other manned US spacecraft before it, they still might have made it. At least they'd have had a better chance.
Beyond Challenger we learned that fragmenting insulation on the liquid fuel External Tank, could fatally damage the fragile insulating tiles on the orbiter itself. Again, none of this would have been a problem if the orbiter didn't ride sidesaddle piggyback along side the External Tank. If the orbiter were mounted atop the External Tank (which would now be a booster in it's own right, with expendable engines of its own) it would not be subject to debris falling off of the launch stack, because such debris would be falling/flying away from the orbiter, not toward it.
All that said, I'm somewhat saddened that we're retiring the shuttle. Mainly, I'm saddened that what is replacing it looks more like a throwback than a step forward. The new spacecraft is called Orion (thanks, but that name was already taken, guys.) I've previously called it "the bastard love-child of the Apollo-Soyuz mission." True, Orion is bigger than Apollo, carrying a crew of six, rather than three, but it's a giant step back from the shuttle which could carry a crew of seven on long duration missions, and allow for EVA without decompressing the entire crew and flight decks of the shuttle. The more I look at it, Orion looks like the product of an agency badly burned by the disasters of Challenger and Columbia. However, unlike the Apollo-1 disaster, which caused NASA to return to the proverbial drawing board to redesign and improve the Apollo capsule, Orion is simply a step backward. In its stock configuration, it cannot accomplish the manifold on-orbit tasks that the shuttle can. It lacks an airlock, and a manipulator arm. Like Soyuz, it uses highly toxic and volatile hypergolic fuel/oxidizer mixtures. Like Soyuz, it uses solar power, rather than fuel cells, which manufacture potable water as a byproduct. In the main, Orion looks like it's actually designed for but two purposes: ferrying crew up and down from the space station, and serving as the new "Command Module" for our "return to the moon" (part of me is wondering why we're going back at this point in time.) In concert with the Altair lander, crews of six will be able to survive on the lunar surface for up to a week while they either explore the Moon, or work on building a permanent lunar outpost.
Even as a space geek, this somehow seems unimpressive to me. It's almost as if we decided that the shuttle was a complete and monumental failure (though cancelling the National Aerospace Plane also helps create this view) and suddenly veered back onto the Apollo development track. I almost want to ask, "why did we decide to build the shuttle, anyway?"
All of this leads me to a horrible thought regarding the manned Mars mission, which is supposed to be the next step, after we go back to the Moon. given the size of Orion and Altair, and the duration of Altair on the surface of an extraterrestrial planet, the mission to Mars is likely to be a highly symbolic "Flags & Footprints" (and Fail) mission, relying upon a much faster opposition class orbit, than the cheaper, more reliable and safer conjunction class orbit. The reason for this is that the conjunction class orbit takes six months to get to Mars, which isn't a problem, but your crew is locked into an 18 month stay on the surface of the planet (or at the very least in Martian orbit) until the launch window for their return journey opens for them. Obviously, such a long stay on the surface of the planet would require a great deal more supplies and consumables than Altair really can provide for. This is why I suspect that we're setting up for an expensive and mostly scientifically useless "Flags & Footprints" mission.
There is hope to save NASA from this boondoggle, but first I must digress into the Russian Soyuz design. Like many space enthusiasts, I initially had very little respect for Soyuz. It uses highly toxic hypergolic fuel, it lacks the triply-redundant systems of the Apollo capsule (which saved the day on Apollo-13). Early on, the Russians had so much trouble getting the damned thing to hold atmosphere, they just gave up and used unmanned Soyuz capsules as Zond space probes to the lunar farside. Soyuz is tiny and cramped, original designed for two cosmonauts, the Russians crammed three of them in there by the hack of not giving them bulky spacesuits. These two problems combined in the 1970s to cost three cosmonauts their lives; upon re-entry, their Soyuz started bleeding off it's atmosphere through an escape valve, due to their long stay in space aboard a Salyut space station, their muscles had weakened and atrophied, and as a result, none of them were strong enough to lift their arms to the valve and screw it closed. I won't even get into the number of early Soyuz missions that failed in various ways on re-entry and hit the earth more like bullets, than anything like a "soft landing."
Though, with typical Russian persistence, and dogged determination, the Russians have turned Soyuz into a pretty robust and capable crew capsule today. The new Soyuz capsules are roomy enough for the crew of three to wear space suits on the way up and on the way down. Improvements in avionics, life support and communication gear have made Soyuz more reliable. It also turns out that I never really understood Soyuz. I always thought that Soyuz was a rough analog to Apollo or Gemini, in which there was a crewed capsule and a service module, with the capsule being the spherical portion on the very top of the Soyuz launch stack. In fact, each Soyuz is three modules: a service module, a crew ascent/descent capsule and an orbital module, which sits on top of the crew module. Thus, unlike Gemini, Apollo and Orion, the Soyuz can support EVA maneuvers without depressurizing the crew module. Once this module has served its function of either docking to a space station or allowing EVA or experiments to be performed, it is discarded prior to re-entry. Frankly, in an understated way, this is genius!
This is also the missing part of Orion. If we're going to copy Soyuz for Orion, Orion needs the capability of launching with an Orbital Module, similar to Soyuz. Alternately, such a module could be launched separately and docked with on orbit, similar to the old Agena rockets used as docking targets in the Gemini program. In any event, such a module needs to provide the missing capabilities of the Shuttle to Orion. The ability to effect on orbit repairs via EVA. Thus, the module would need to be equipped with an airlock, EVA equipment like EVA spacesuits, MMUs, and a robotic arm, similar to the shuttle's robotic arm. If the module were made large enough, spare/repair parts like new instruments for the Hubble Space Telescope could also be loaded on board.
Though NASA already has (shelved) plans for such a spacecraft. It was called the Orbital Maneuvering Vehicle, and it was designed for most of the tasks I mention here. The OMV was basically a space tug with on orbit servicing, repair and EVA capability. It's job would have been to assemble parts of the space station in orbit, back when such designs were more grandiose than currently. OMV was ultimately killed off because the shuttle could do pretty much everything the OMV was designed to do, but without the shuttle, building and flying something like the OMV starts to make a lot more sense, particularly if the OMV has a longer service life and endurance on orbit than Orion.
There's also another piece of space hardware missing. A space station at one of the Earth/Moon Lagrangian Points (L1 makes the most sense) could be an orbiting interplanetary spaceport, offering cheap (energy-wise) access to the Moon, Mars and the rest of the solar system via use of the Interplanetary Superhighway. Unmanned missions launched into the IPS from the L1 station could be designed to eventually, or even periodically, return there for service or repair. Supplies and equipment could also be kept at the L1 station for a rescue mission to the lunar base, if necessary (or, y'know, if they unearth a large, impossibly smooth and regular black monolith in the depths of some lunar crater.)
In conclusion, as it stands now, Orion is a monumental step backwards in capability from the shuttle, but this problem can be addressed by the design and deployment of an Orion Orbital Module, the OMV (or both). In any event, an L1 station, provides capabilities not currently offered by ISS. These technologies and systems would transform the Orion program from one predicated upon the setbacks encountered in the shuttle program, to a new, robust and vigorous space hardware platform which offers all of the capabilities of the shuttle, but in an updated package.
Beyond Challenger we learned that fragmenting insulation on the liquid fuel External Tank, could fatally damage the fragile insulating tiles on the orbiter itself. Again, none of this would have been a problem if the orbiter didn't ride sidesaddle piggyback along side the External Tank. If the orbiter were mounted atop the External Tank (which would now be a booster in it's own right, with expendable engines of its own) it would not be subject to debris falling off of the launch stack, because such debris would be falling/flying away from the orbiter, not toward it.
All that said, I'm somewhat saddened that we're retiring the shuttle. Mainly, I'm saddened that what is replacing it looks more like a throwback than a step forward. The new spacecraft is called Orion (thanks, but that name was already taken, guys.) I've previously called it "the bastard love-child of the Apollo-Soyuz mission." True, Orion is bigger than Apollo, carrying a crew of six, rather than three, but it's a giant step back from the shuttle which could carry a crew of seven on long duration missions, and allow for EVA without decompressing the entire crew and flight decks of the shuttle. The more I look at it, Orion looks like the product of an agency badly burned by the disasters of Challenger and Columbia. However, unlike the Apollo-1 disaster, which caused NASA to return to the proverbial drawing board to redesign and improve the Apollo capsule, Orion is simply a step backward. In its stock configuration, it cannot accomplish the manifold on-orbit tasks that the shuttle can. It lacks an airlock, and a manipulator arm. Like Soyuz, it uses highly toxic and volatile hypergolic fuel/oxidizer mixtures. Like Soyuz, it uses solar power, rather than fuel cells, which manufacture potable water as a byproduct. In the main, Orion looks like it's actually designed for but two purposes: ferrying crew up and down from the space station, and serving as the new "Command Module" for our "return to the moon" (part of me is wondering why we're going back at this point in time.) In concert with the Altair lander, crews of six will be able to survive on the lunar surface for up to a week while they either explore the Moon, or work on building a permanent lunar outpost.
Even as a space geek, this somehow seems unimpressive to me. It's almost as if we decided that the shuttle was a complete and monumental failure (though cancelling the National Aerospace Plane also helps create this view) and suddenly veered back onto the Apollo development track. I almost want to ask, "why did we decide to build the shuttle, anyway?"
All of this leads me to a horrible thought regarding the manned Mars mission, which is supposed to be the next step, after we go back to the Moon. given the size of Orion and Altair, and the duration of Altair on the surface of an extraterrestrial planet, the mission to Mars is likely to be a highly symbolic "Flags & Footprints" (and Fail) mission, relying upon a much faster opposition class orbit, than the cheaper, more reliable and safer conjunction class orbit. The reason for this is that the conjunction class orbit takes six months to get to Mars, which isn't a problem, but your crew is locked into an 18 month stay on the surface of the planet (or at the very least in Martian orbit) until the launch window for their return journey opens for them. Obviously, such a long stay on the surface of the planet would require a great deal more supplies and consumables than Altair really can provide for. This is why I suspect that we're setting up for an expensive and mostly scientifically useless "Flags & Footprints" mission.
There is hope to save NASA from this boondoggle, but first I must digress into the Russian Soyuz design. Like many space enthusiasts, I initially had very little respect for Soyuz. It uses highly toxic hypergolic fuel, it lacks the triply-redundant systems of the Apollo capsule (which saved the day on Apollo-13). Early on, the Russians had so much trouble getting the damned thing to hold atmosphere, they just gave up and used unmanned Soyuz capsules as Zond space probes to the lunar farside. Soyuz is tiny and cramped, original designed for two cosmonauts, the Russians crammed three of them in there by the hack of not giving them bulky spacesuits. These two problems combined in the 1970s to cost three cosmonauts their lives; upon re-entry, their Soyuz started bleeding off it's atmosphere through an escape valve, due to their long stay in space aboard a Salyut space station, their muscles had weakened and atrophied, and as a result, none of them were strong enough to lift their arms to the valve and screw it closed. I won't even get into the number of early Soyuz missions that failed in various ways on re-entry and hit the earth more like bullets, than anything like a "soft landing."
Though, with typical Russian persistence, and dogged determination, the Russians have turned Soyuz into a pretty robust and capable crew capsule today. The new Soyuz capsules are roomy enough for the crew of three to wear space suits on the way up and on the way down. Improvements in avionics, life support and communication gear have made Soyuz more reliable. It also turns out that I never really understood Soyuz. I always thought that Soyuz was a rough analog to Apollo or Gemini, in which there was a crewed capsule and a service module, with the capsule being the spherical portion on the very top of the Soyuz launch stack. In fact, each Soyuz is three modules: a service module, a crew ascent/descent capsule and an orbital module, which sits on top of the crew module. Thus, unlike Gemini, Apollo and Orion, the Soyuz can support EVA maneuvers without depressurizing the crew module. Once this module has served its function of either docking to a space station or allowing EVA or experiments to be performed, it is discarded prior to re-entry. Frankly, in an understated way, this is genius!
This is also the missing part of Orion. If we're going to copy Soyuz for Orion, Orion needs the capability of launching with an Orbital Module, similar to Soyuz. Alternately, such a module could be launched separately and docked with on orbit, similar to the old Agena rockets used as docking targets in the Gemini program. In any event, such a module needs to provide the missing capabilities of the Shuttle to Orion. The ability to effect on orbit repairs via EVA. Thus, the module would need to be equipped with an airlock, EVA equipment like EVA spacesuits, MMUs, and a robotic arm, similar to the shuttle's robotic arm. If the module were made large enough, spare/repair parts like new instruments for the Hubble Space Telescope could also be loaded on board.
Though NASA already has (shelved) plans for such a spacecraft. It was called the Orbital Maneuvering Vehicle, and it was designed for most of the tasks I mention here. The OMV was basically a space tug with on orbit servicing, repair and EVA capability. It's job would have been to assemble parts of the space station in orbit, back when such designs were more grandiose than currently. OMV was ultimately killed off because the shuttle could do pretty much everything the OMV was designed to do, but without the shuttle, building and flying something like the OMV starts to make a lot more sense, particularly if the OMV has a longer service life and endurance on orbit than Orion.
There's also another piece of space hardware missing. A space station at one of the Earth/Moon Lagrangian Points (L1 makes the most sense) could be an orbiting interplanetary spaceport, offering cheap (energy-wise) access to the Moon, Mars and the rest of the solar system via use of the Interplanetary Superhighway. Unmanned missions launched into the IPS from the L1 station could be designed to eventually, or even periodically, return there for service or repair. Supplies and equipment could also be kept at the L1 station for a rescue mission to the lunar base, if necessary (or, y'know, if they unearth a large, impossibly smooth and regular black monolith in the depths of some lunar crater.)
In conclusion, as it stands now, Orion is a monumental step backwards in capability from the shuttle, but this problem can be addressed by the design and deployment of an Orion Orbital Module, the OMV (or both). In any event, an L1 station, provides capabilities not currently offered by ISS. These technologies and systems would transform the Orion program from one predicated upon the setbacks encountered in the shuttle program, to a new, robust and vigorous space hardware platform which offers all of the capabilities of the shuttle, but in an updated package.