Jump to content
Sign in to follow this  
C James

Atlantis: final flight of the Shuttle

Recommended Posts

The Space Shuttle Atlantis left the Space Station for the final time today. If all goes well, in the early hours of July 21st (east coast time) she'll fire her orbital maneuvering engines for the last time, above the Indian Ocean, to begin a re-entry profile that will see her touching down just before 6am in Florida. When her wheels stop, she will never again move under her own power.


The last shuttle launch is now history. With Atlantis's landing, the Shuttle program will be over.


It has been a long history, over 30 years, since Columbia's first flight in 1981. Atlantis herself first flew in 1985. Her current flight is her 32nd, and last, return to space.


The Shuttle era is over. They can never fly again. They are aging airframes, and the decision was made to retire them. There are arguments as to whether they should have been kepty flying a while longer, but those arguments, good and bad, became moot about two years ago, when the parts supply line began being dismantled. Just one example of this is the shuttle external tank production facility in Louisiana; once it shut down, we lost the ability to make external tanks, and without them, the shuttle cannot fly. That is just one example, but there are many; most of the internal components are similarly irreplaceable.


The Shuttle was, at once, a magnificent achievement and a magnificent failure. Its primary purpose was to provide cheap, routine access to space. In this, it failed utterly. Each launch had a combined cost of over a billion dollars in today's money, and that made it far too expensive. It was also far from routine; Two shuttles, Columbia and Challenger, were destroyed, killing their crews.


The Shuttle had capabilities we are unlikely to ever see again in our lifetimes. Here are six things it could, and did do, that no proposed replacement can.


The worst is yet to come. From today and for years to come, the only way an American will reach space is by paying the Russians for a ride. Without the Russians, the US loses the most expensive object man has ever made, the Space Station. If anyone thinks that the Russians won't use this as leverage to the point of blackmail, they are in for a very rude awakening.


Nasa does have vehicles on the drawing-boards. Unfortunately, their concepts are an engineering and fiscal disaster. The current idea is a "Shuttle derived" unmanned heavy-lift launch vehicle. The problem is it was designed by a committee of politicians, literally, and the results are what one would expect; a vehicle that saves the worst (and dangerous) aspects of the shuttle program while throwing away its greatest capabilities. This vehicle is derisively called the Senate Launch System in the space industry. Essentially, take a Shuttle external tank, stretch it, and use it as the first stage core of a conventional-looking staged rocket. Tack on two or more enlarged Shuttle solid rocket boosters, and then build an upper stage. It would be powered by five space shuttle main engines, and would be a large cargo launcher. This may sound simple, but it is far from it. Everything would need redesigning, right down to the engines. The Space Shuttle Main Engines (SSME's) are the most advanced hydrogen-oxygen engines ever built, and are made to be reusable. They are also incredibly expensive to build, and we no longer have the ability to build them. With this design, they could not be recovered. The plan is to use existing shuttle engines. That sounds fine, until one realizes that we have exactly fifteen of them. So, an all-new engine would be needed, if there is ever to be a fourth flight of the Senate Launch System. (the actual proposal name is Space Launch System). The development cost would be around ten billion, and per launch costs would exceed that of Shuttle.


I grew up as a huge fan of NASA. Therefor, it pains me greatly to say this, but I do not want to see NASA design and operate a launch system, because they have proven that they cannot do so efficiently. This is not all their fault; congressional pork is a huge factor. The Shuttle program is proof of this; it was billed as cheap to operate, and was anything but. The reason is simple; the government turned the Shuttle program into a catch-all and a jobs program. Thus, it failed to deliver what it promised.


And incidentally, keeping the costs down is not the only reason I condemn NASA and congressional pork for screwing up the space program. We have seven dead astronauts, lost in the Challenger disaster, who paid with their lives for pork-barrel folly. I can prove this. Remember why Challenger was destroyed; an O-ring (a seal, between two segments of the solid rocket booster)burnthrough, on a solid rocket booster, resulted in a flame jet cutting into the booster support, causing structural failure and the booster rotating into the external tank. Now, why did the o-ring fail? Part of it was the cold; it's rubber, which looses it's elasticity in the cold, and they launched (against the warnings of the engineers) in freezing temps. The other part was design; they'd had blow-by events before, and ignored them. The fix was to redesign the seals to have double o-rings.


Posted Image

Here's the damning bit: Why, exactly, is the Shuttle SRB segmented? There are four main segments to the solid propellant, and the o-ring junctions are between each of the segments (where the cylindrical segments join together). This is a rather kludgy way to build a rocket thrust chamber (which is what the entire body of a solid rocket essentially is). Why not build it as one unit?


Because it's built in Utah, and it's too heavy to ship whole by air. That means it has to go by rail, and that means, thanks to tunnel diameters and rail curve issues, it has to be segmented, and no larger in diameter than it is. (yep, a limiting factor on a spacecraft was the diameter of 19th century railroad tunnels).


So, why build it in Utah? pork barrel Politics. Morton Thiokol's design bid was rated 4th of four by an initial review, because it was both the most problematic and most costly, but Thoikol won the bid anyway, for political reasons. And seven astronauts died.


It didn't have to be. Aerojet's bid was for a single-peice, single-pour solid rocket, larger in diameter than an SRB, which would have burned for around 20 seconds longer. It was simpler, cheaper, and safer, and would have made refurbishing the boosters after recovery cheaper and easier too. But they wanted to build it in Florida, near the launch site, for obvious practical reasons. But political and pork beat science and common sense. This is just one glaring example of how political pork and making space a jobs program has screwed the program, made it too costly to operate, and also killed people.


So, with the last flight, I remember both the triumphs and failures of the Shuttle program, and mourn also, the loss of what might have been, had the program been done right.


I believe that space is mankind's future, so I'm far from advocating an end to spaceflight. I advocate the opposite; routine access to space. To have that, you have to make it affordable. What it boils down to is reducing the price per pound to orbit. There are many ways to do this, with technology we have today. What is clear is that government is not the route; government may be many things, but a cost innovator it isn't. So, if you want low cost, you need to look elsewhere.


One place to look; satellite launch companies. They are flying payloads to orbit today, at far lower costs than government can manage. They can fly and recover a space capsule as easily as NASA can. Actually easier today, becuase at this moment, only one organization in the US is currently flying a vehicle that's made to be manned, and have put it in orbit and then returned it safely to earth. It's called the Dragon capsule, and it flew a few months ago, on a Falcon 9 rocket.

Posted Image

It's currently intended for making cargo runs to the space station (expect to see one around September), but it was designed for manned use. That capability was built in. All it needs to make it manned-capable is a life support system (easy and fast to do with off-the-shelf parts) chairs, and a control panel. If we wanted to, we could have astronauts in orbit by this time next year, after a couple of unmanned tests, because the rocket and capsule are already operational today. Would it have the capabilities of the Shuttle? No, but neither does anything NASA has in mind.


Here's the key difference; cost. The price of a Falcon 9 launch (and they do this commercially) are just under 55 million. Even if your double it for a manned launch (and no estimate I've seen is that high) you're still at under one tenth the cost of a Shuttle launch.


SpaceX's Falcon 9 and Dragon capsule aren't the only game in town, either. Sierra Nevada corp has Dreamchaser, a spaceplane that will launch on a rocket and return like a shuttle. There are others, both for launch vehichles and spacecraft.


Now, for the heavy lift cargo rocket the Senate wants NASA to build... It simply isn't needed. One reason, it's farcheaper to do it commercially. SpaceX has a design concept, the Falcon Heavy, basically three Falcon 9 first stages strapped together, with propellant crossfeed. Cost per pound to orbit? Around $1000, which is about 1/10th what anyone but SpaceX can do today. Heavy lift? It is, with a payload of 120,000 pounds (initial design, ongoing improvements may well increase that). Shuttle's payload, for comparison, is around 1/3 that to ISS orbit.

And the best part of all; this does not need a multi-billion years-long program to develop it. It'll be on the pad in just over a year, preparing for its first flight in late 2012 or early 2013. it's already being built.

Posted Image


Here's another number set; the total development cost, including engines, for the Falcon family (Falcon 1 and Falcon 9) is around 700 million, including several flight tests, plus the Dragon capsule, command module, etc.. Pushing this to Falcon Heavy will bring it in just under a billion, most likely. Compare that to NASA, who managed to spend 750 million or more on the Ares 1x launch. Just one launch, using an existing Shuttle SRB as a first stage, and a dummy upper stage. There was exactly zero hardware commonality between Ares 1X and the proposed Ares 1 launch system. NASA is also spending over 2 billion on a capsule from Boeing, that will be years in the development. And no way to launch it. (and forget the Senate Launch system; it's unmanned, and hopefully will be canceled).


I think it's time for NASA to start buying rides to orbit from commercial providers; offer a performance-based contact. Let NASA focus on what it does well; missions in space, rather than what it does very poorly; designing and operating a launch system.


So, I see the end of the Shuttle program as the end of an era. What comes next? We don't yet know. I can only hope that, this time, the choices will be wise ones.


Farewell, Atlantis, the last of the shuttles.

Posted Image


You have ridden the fire one last and final time, soon to return forever, to to the earth from whence you came.

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Create New...

Important Information

Our Privacy Policy can be found here. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue..