Bottom line: We don't have an SSTO. We do not have any real lift capability that is man-rated. People in space are what sells the program to the public. Without the political support, robotic research become 4th tier.
As for those who query about the risk - we know the risk. Would you turn down a shuttle ride, even now? The short America-Centric answer is "No guts, no glory". There's no price tag on that - our people risk their lives every time they go out.
The other long term component - we need people off planet in a viable, sustainable environment - if we don't have an off-planet colony, first nicely tailored bioplague, and humanity is toast. This Plague Day is either tomorrow, or today and we just don't know yet. The NIH had the smallpox genome on-line for years, and only pulled it off in the last few years. How many copies are out there? And we can build a virus from the DNA fragments. It's been done. If it's tweaked, then any vaccines are probably not useful. Vaccine creation times are what, 6-12 months?
If a tailored plague is too esoteric for anyone, if Yellowstone blows, humanity is also in trouble. The last major event, written about in SciAm, opines that 80,000 years ago, only a handful of survivors survived a massive climate change from volcanic effects, if I remember correctly.
We *might* see a dinosaur killer asteroid before it hits.
How likely are the last two in the next 100 years? Not terribly likely. The first one is a near certainty. We have plenty of nihilistic loons globally to make this happen.
I would have liked something a little different from the shuttle, but I vastly prefer the shuttle to nothing. It was not the best engineering answer (cheaper, dumber boosters would have been better, in my opinion, or SSTO, or other cheaper approaches). And given the loss of the ships and crews, it may not have been the best political answer. But it fired a DREAM (does anyone remember the film "The Dream Is Alive" that came out right after the Challenger explosion? If you have not seen it, GET IT.) I wanted to GO. If a thing is worth doing, it is usually not risk-free (like settling America and digging the Panama canal as mentioned by twk). (Even getting an engineering degree is not risk-free...after all, you might not find a JOB...)
I concur!! Anything new never works as advertized right away. There is a learning curve.
Also the shuttle has/had the ability to retreave space hardware. Do any of the new systems have this capability?
I still remember the first shuttle lift off when I was akid and awe that caused in me thousands of miles away watching on TV. It was such a motivational thing to witness in science. It made my nerves twitch in exitement and I held my breath as the magnificent silvery thing slid out of the huge cloud of smoke at liftoff.
I would argue that it has done it's part in our understanding of the outer space and gave valuable lessons for how humans can work in outter space. It may have burned a lot of $$ but that was not by design but in its course it certainly has made science popular and many a kid take up higher studies in science.
This is coming from a former disillusioned 10 year NASA employee, and have a drawer full or technical award to prove it:
We are now having to pay the Russians to get people into orbit, and supply our very, very, expensive Space Station
If you can put a positive spin on this situation, you are truly a master of the art!
I think the only way forward now is to launch many more unmanned probes to Mars to see how far it is from being habitable, and help us determine if there is any way to adjust. We would need this information to help prepare for a manned mission to Mars anyway.
I am saddened by a number of the comments above that belittle one of the worlds most significant achievements with political opposition and the age old saw about loss of life. Those good men who gave their lives in that endeavor and the loved ones they left behind knew full well what they entered into and did so with an attitude that I am afraid very few these days are able to understand. That attitude caused similar good men to sail due west from England for the first time, caused them to find out what was in the interior of the African continent, and caused them to dig a ditch across some pretty miserable terrain called panama. Without that willingness, bravery, boldness, or whatever you wish to label it most of the good things we take for granted these days would be missing or harder to enjoy.
The politics of today have very nearly stopped such honerable endeavors because so many diverse and devicive interests will not allow anything but their personal pet ideas go foreward. cost and danger are the common stopping issue and are also the common hallmark of the best history can show us.
We are protecting ourselves, and spending our resources on things that encourage and support those who do nothing to the extent that our very civilization has begun it's decline. We are by our politics and economics bringing progress itself to a halt.
I look back with satisfaction and forward with dispair and personally hope I can enjoy the rest of my time here before life deteriorates to far.
Those who will propose anything negative about that piece of history better be proposing something much better or butt out.