I’m Gordon – a different Gordon. While Gordon is away he asked me to send over a post today. I keep my own blog and I’m also a professor at the University of Washington. I’m an experimental physicist working on the ALTAS and DZERO experiments. But I’m not going to talk about those. :-)
So – who’s been following the Apollo 8th’s 40th anniversary? NASA has put together a pretty cool web site with lots of great resources. The Apollo mission was truly one of our crowning technological achievements. And at a time like this you can’t help but look forward at the same time you look forward. And you run right into the same questions as always: can America afford space exploration? What should the program look like in the near and long-term future?
Ignoring the moral factor for the country, the science case for exploration is pretty strong in my view. There is a lot we don’t know about our own earth, about the moon, and, especially, about near-by planets. Telescopes that are out of the earth’s atmosphere have unique advantages when it comes to deep space exploration. We have a lot yet to discover about the planet we currently live on and on the solar system, galaxy, and universe we inhabit. I’m always in favor of more knowledge. Can we afford it. The USA? Certainly! I can’t think of many crises in the USA that would warrant totally canceling the space program (or any other science program for that matter). No country can survive without a balance in how it spends money – on the present as well as the near and far futures. The global warming crisis has already taught us how important it is to know where we live and how we are affecting the environment around us (no matter which side of the debate you are on!).
So what should be space program look like? I think it should look more like this:
and less like this:
The reason is bang-for-the-buck. I think it is pretty hard to deny that sending people up into space is amazingly expensive right now. You have to get them up, and you have to get them back. You have to supply life support. Escape hatches. Lots of space you might fill with equipment is people and oxygen and etc. People are amazingly good at improvising. Something goes wrong – your buggy gets stuck on a rock or similar – people can adapt. That is where they really beat out a robot. We can get an idea of something that needs to be done, and quickly come up with a plan that balances all the risk factors, the obstacles, and still achieves the goal. Heck, if on the way to accomplishing the plan something interesting distracts us – well, that is useful too – perhaps we made one of those serendipitous discoveries; whatever: we can quickly evaluate the interesting thing and decide if it is just a rock reflecting light or some form of Martian currency. Finally, because we have to bring back the humans, bringing back that discovery has very little additional cost (other than biohazard containment!).
Robots have different strengths. Many of the things I’ve listed above robots aren’t so good at. On the other hand, they can stay on a planet for months or years. Need no life support – so getting them there is a lot cheaper. We are getting good enough at creating these exploration robots that we can given them simple tasks and they can take care of themselves. Since they are there for months or years at a time, it doesn’t matter if they aren’t extraordinarily efficient, we can just have them repeat the exercise several times until they get it right. And, perhaps because we don’t have to carry all the support equipment for humans out there, we can stuff an extra scientific instrument or two on the device and get that much more information out.
The thing is – the science case is overwhelmingly in favor of the robots right now. Check out the poster-child for this – the Mars Rover Missions. 5 years of exploration and science. Less than one billion bucks. What did putting a man on the moon cost? I can’t find firm numbers – but it isn’t uncommon to see numbers like 100 billion. Now, I don’t think going back to the moon would be that expensive – it usually is cheaper the second time around. Mars, which was Bush’s stated goal, would probably be that or close to it. For that kind of cost you could littler Mars with rovers and send a few to other planets.
Maybe these commercial endeavors getting people into space cheaply will change the cost/benefit equation. If successful they may well change my opinion of things like the space station – things in low earth orbit. If you could fly the parts up there cheaply and ferry people back and forth – then it might just be another expensive government lab where micro-gravity experiments could be done (in isolation too). But getting people further out to the Moon or Mars would still be very expensive – I doubt I’d be convinced.
Besides, the more experience we have with sending objects up the better prepared we will be when the aliens arrive. ;-)
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. Here, x is the position of our wave, t is the time, and v is the speed of propagation. Again, check this; use 
, 
and 
, and remember 
if you need it.
and 
. The two solutions are identical in everything but time. That is, one solutions is a wave moving forward in time, and the other is a wave moving backward. Without loss of generality, a physicist can toss the unneeded solution away.
. Since both 
and 
are constants, that implies v is also a constant. It turns out v is almost 
, which is the speed of light. Thus, v is c, the speed of light, and hence, light is an electromagnetic disturbance.
