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Where Should Space Exploration Go From Here?
Since Congress has been steadily cutting back on support for NASA, Nick suggests this idea: "I'm sure there are many taxpayers out there like me that would love to see NASA's budget doubled. The problem is there isn't enough support to get congress to increase the budget by that amount, and I really don't want people to pay that don't care to. I propose an opt-in, one-time contribution box added to tax returns. I would require that my money be used only to advance the space program with either a shuttle replacement, an extra crew compartment for the space station, or a launch vehicle for a manned trip to Mars. Would you support a bill that would allow taxpayers to voluntarily contribute money to NASA? Are you ready to put your coin where your Dreams are?"
Although some of his arguments are not convincing or even insulting ("Did Israeli astronaut Ilan Ramon really have to be there to push a couple of buttons..."), the article makes several important points. Here's one of them:
But the space shuttle has not lived up to promises, and there are no current technologies which will get space travel to a reasonable cost. Plus, there's really a lack of a mission. I'd say the hubble and other satellites are the only worthwhile things it's done. Given finite resources, what else could we do with those billions? A fusion manhattan project? Thousands more grants to scientists? The end of oil dependence? These are all more valuable things than going to space right now. I hate to say it, but rationally I believe we're better off shuttering nasa and diverting the money to other science endeavors. And if you consider all the possible uses for the money, it becomes more attractive to shutter nasa. Think of the millions in jeapordy from AIDS, and the horrors of Africa and parts of Asia.
China is planning on becoming a lot more active in space shortly. I sort of feel this will give the US a huge incentive to give more funding to NASA, there's nothing like competition to get the money pumping in.
Ahem, I point you to the most recent story on my website you will find this link with a pretty graph
So, enough with the "cuts" talk, the budget has risen $900 million in the past 2 years and is slotted for another $470 million. If you want to debate whether this is "enough" then fine, but it had been in decline for a while before Bush RAISED it two years i a row and proposed raising it again BEFORE the Columbia re-entry.
Eve Fairbanks says I drive a hybrid!LOL
Uh, no. Nobody's figured out how to keep a scramjet lit. The Australians did it for about six seconds, which is a record for a free-flying vehicle.
Last semester my classmates and I wrote a draft for the AIAA design paper competition for a reusable, air breathing single stage to orbit "rocket" plane.
Bottom line? Unless we get a lot better fuels, or radically lighter structures, it's not going to work. That's even assuming that you can keep the scramjet lit. (which would get you a PhD, if not a Nobel prize)
X-30 is not the way. Venture Star was much closer. A shuttle-oid with Boeing's fly-back boosters might be a really good short term solution.
Why yes, I AM a rocket scientist!
Money certainly is the problem. NASA, and space exploration needs to be a higher priority than some of the garbage we pour money into. Here's some numbers -
NASA's budget for 2003 - now $15.5 billion after the Columbia tragedy
Military budget for 2003 - $396 billion
Now of course I think the military needs a massive amount of money, but they spend it like water, and on things that we do not need.
Here's an example of new weapons we are buying that are included in the 2003 budget -
the Army's RAH-66 Comanche helicopter (Boeing and the Sikorsky Aircraft Division of United Technologies, $941 million); the Air Force's F-22 Raptor (Lockheed Martin, Boeing, and the Pratt and Whitney Division of United Technologies, $5.2 billion); the Navy's F-18E/F fighter plane (Boeing, General Electric, and Northrop Grumman, $3.3 billion); Joint Strike Fighter/F-35 (Lockheed Martin and Northrop Grumman, $3.5 billion); the V-22 Osprey (Boeing Vertol and the Bell Helicopter Division of Textron, $2 billion) the DDG-51 destroyer (Bath Iron Works and the Ingalls Shipbuilding Division of Northrop Grumman, $2.7 billion); the Virginia class attack submarine (Electric Boat Division of General Dynamics and the Newport News Shipbuilding division of Northrop Grumman, $2.5 billion); the Trident II Submarine-Launched Ballistic Missile (Lockheed Martin Missiles and Space, $626 million); and the Crusader artillery system (Carlyle Group/United Defense, $475 million).
Total - $21.2 billion
These are known as "cold-war relic" programs. In fact, many of these systems were mentioned as candidates for major reductions or cancellation during the Bush campaign and during the early months of Secretary of Defense Donald Rumsfeld's defense review. In addition they have been criticized in the past by Bush advisors or independent advocates of military reform as being too heavy (the Crusader), redundant (the three new fighter plane programs), or otherwise out of step with our current situation.
If our space shuttles could bomb Iraq we would be getting new ones all the time.
Anti-social? My code is just platform-specific.
ya think? I dont think the INternet has had all that great an impact on mankind. The moon walk, however, has. Possibly not the action.. but the technology behind it..
# To p
Soles designed for moon boots are used in tennis shoes.. sports bras, portable coolers that run on your cigarette lighter, scratch and fog resistant coatings for your glasses, teflon, composite golf clubs, quartz timing technology, compact hi-yeild batteries.. these are ALL the result of NASA research for things necessary for space flight.
Digital Imaging Breast Biopsy system, and Laser Angioplasty.. also both spinoffs...
Im not saying the experimental military stuff is useless.. but damn dude.. NASA has invented or necessitated the invention of a hell of a lot of stuff we all take for granted these days!
Maeryk
http://www.thespaceplace.com/nasa/spinoffs.html
Feminine Protection? What is that? A chartreuse flame thrower?
Actually, sir, you are wrong here. Nuclear propulsion is inherently VERY, VERY, dangerous if its used in the boost phase. You have a hot, running nuclear pile. It has to have LIGHTWEIGHT SHIELDING. It has to produce an enormous amount of energy for the first few seconds during liftoff, to minimize the propellant used. If it melts down, you have hot radioactive debris everywhere. A fusion plant, even if possible, will be many decades, maybe centuries away before one with the power/weight ratio exists, if ever (think of all the lasers or magnets needed...much weight). There's an enormous difference between using a hot nuke plant to reach orbit and using a regular rocket carrying cool, freshly made fuel rods.
The costs to minimize this danger, and the liability if it fails, would make the space shuttle seem cheap.
However, there is in fact a third option you have not mentioned. A laser beamed from the ground would superheat an inert propellant block on the spaceship. Pulsed in the right timing, and it would generated a planar shockwave. No thrust nozzles or anything needed. Merely a heavy cube of propellant and the spacecraft bolted on top, as well as some sort of stabilization system. Much safer, nothing to explode, astronaut escape vehicles possible, and a far far better propellant/payload ratio (the laser would heat the propellant up at least 10 times hotter than a conventional rocket can reach). For the initial liftoff phase a short linear accelerator might be used to give the spacecraft its initial kick (and providing a safety delta V if the laser on the ground fails)
This is something that would make space travel feasible in mass. Since the main power system, and most of the complexity , is on the ground (plenty of room to have backups then) the maintainence and operation costs would be far lower. Its estimated that unmanned payloads might reach orbit for perhaps $60 a pound (just the electricity to run the laser).
It gets a little hairier than that. : )
A scramjet is a Supersonic Combusting Ramjet. Let's back up a step. A ramjet is an engine that uses shock waves, instead of fan-shaped compressors, to compress the air to mix with your jet fuel. If you don't grok why you need to compress air, go thou and Google search for a description of turbojets or any other internal combustion engine. This is going to be a long enough post as it is. : )
As the ramjet passes air through the shock wave system in its inlet, the air a) heats up and b) slows down. The speed of sound increases with temperature, and the speed of the gas goes down (from the Mach 3 to Mach 6 where ramjets can typically be operated). At some point, the air is actually subsonic. At that point, fuel is introduced and ignited. Hot air go out back of motor, airplane go forward.
Scramjet is basically the same idea, except without the slowing the air down to subsonic part. The entire combustion process happens in a supersonic airflow. While the physics of "low speed" combustion are pretty well understood, doing the same thing in a high speed flow is seriously non-trivial. In the paper we wrote, we adopted a technology called a "hyper-mixing injector" to dump fuel into the stream, and we actually let the high temperature air ignite the fuel all by itself. Keeping that fire going is, well, hard. Stick a Zippo out your sunroof. You get the idea.
Scramjets are way tricky. If you don't manage the airflow very precisely by varying the geometry of the intake section and not maneuvering the aircraft EVER, you might get a condition called an "unstart". Basically, all the nice shock waves you've been using to compress your gas glom together into a big strong shock wave perpendicular to the gas flow directon in your inlet, and basically at that point the temperature and pressure in your combustion chamber go from really really improbably high (which is good, and you've designed for that) to freakin' nutty crazy blow-up-spaceship now high, and you start collecting pieces of the thing across three states.
See recent Columbia accident for a much less violent example of what would happen. It would be far worse.
Scramjets are scary. Yeah, they might work, but they're REALLY finicky, and I don't believe our flight control systems are sufficiently advanced to fly them reliably and safely.
And forget about having a guy driving the plane. If you pitch the nose a few degrees off the trajectory, or roll the airplane at all, the shock system will change formation, and very likely you won't even know what hit you. No way to do it without computer control end-to-end.
You might have observed that the low speed for a ramjet is Mach 3. In order to have the shock waves in the inlet, you already have to be going really fast. You might be interested to know that the SR-71 used a partial ramjet cycle at its Mach 3 cruise condition. It also had a turbojet engine core to accelerate it to ramjet operating speeds.
Nuclear powered plasma would work great in an atmosphere...if you don't mind dumping a very highly radioactive plume all over Florida.
Actually, even though the specific impulse of the nuclear rockets is really good (specific impulse is a good measure of the fuel efficiency of a rocket. It tells you the number of pounds of thrust you get per pound of fuel) the peak thrust values are not very high. In other words, it'll be a good interplanetary drive, but really not ideal for launch systems (bad environmental issues aside).
Why yes, I AM a rocket scientist!
Orbital insertion? Equivalent speed is Mach 25. (of course, in orbit, there is no speed of sound, so Mach numbers don't apply, but for purposes of this discussion...)
SR-71? Mach 3. Teeny payload. However, the design we worked out used upgraded J-58 engine cores from the SR-71 to get up to scramjet operating speeds. And yes, having to fly for a long time while you accelerate is a big problem. You're burning just incredible amounts of fuel the whole time, and burning fuel to accelerate the fuel you need to burn to accelerate fuel that you need to burn to accelerate. Ad nauseam.
The other problem with air breathing rocketry is wave drag. In order to get the same thrust as a rocket, an airbreathing space craft's cross-sectional area has to be about 1.5 to 4 times as large as the rocket is to ingest enough air. Since wave drag (the primary drag force at high speeds) is very strongly dependant on cross sectional area, you swiftly get to a point of diminishing returns. Let's make up some numbers.
Rocket A thrusts at 100lbs, and weighs 10 lbs, and has (say) 10lbs of drag acting on it. That gives it an excess thrust of 80lbs to do the force=mass*acceleration thing.
Scramjet B thrusts at 100lbs, flys mostly horizontally so its weight isn't a factor (it's a lifting body), but has (say) 80lbs of drag on the airframe. So it only has a quarter of the thrust available to accelerate as our rocket, meaning it will take much longer to get to orbital insertion velocity.
In a nutshell, that is the problem with air breathing rocketry.
Why yes, I AM a rocket scientist!
Perhaps they should have priced it in terms of Shuttle missions. The shuttle has launched over 100 times, at a typical cost of about $500M per launch equals roughly $50G, so their elevator would be priced at 80 shuttle missions or under 4/5 of the money spent so far running the Shuttles.
Speaking of which: in terms of fatalities per passenger mile, they're much safer than jetliners, orders of magnitude better than your car. OTOH, you car doesn't cost billions of dollars to replace if you write it off. OT3H, I'd be really happy if I got that many miles out of any car, ever. (-:
Got time? Spend some of it coding or testing
And so it should. Listen. If some commerical launch goes wrong, do you honestly believe that any business will have the money to clean it all up? I mean if it hits a population center we're talking about some crazy cash. The government would have to bail them out, no question.
The whole notion of a corporation is 'limited liability'. The idea was concieved to encourage exploration of the New World when the loss of a ship could completely bankrupt the financial backers. That's what the 'Ltd.' stands for. Limited liability means if something goes real bad then "Super Space, Ltd." pull a Chapter 11 and the people in the crater are SOL.
Wah!
And now, to needlessly explain the stupid pun...
For the purposes of weak humor, he interprets "mass destruction" as the destruction of mass, rather than destruction of an indeterminate, massive quantity. Since anti-matter destroys mass, he suggests that Iraq must posses anti-matter if they indeed have weapons of "mass destruction".
Ironically, mass destruction is not even a word.
Wasn't teflon developed to protect tubes used to process uranium?
Why, I'm so glad you asked. Teflon was first created by mistake by a researcher studying flourocarbon variants. The goal was fluids for refrigeration systems, not teflon. After a series of tests he found a strange waxy mass in the chamber. That was teflon.
It is worth noting that this is a perfect example of the sort of free-form experimentation allowed to proceed in an unplanned direction that NASA has proven so very bad at pursuing.
Rustin
Data is the lever, rigor the fulcrum, brains the force that drives it all.
A lot of people signed in the campaign, but the government, of course, did not change anything.
Perhaps the government realized that if it did cut back on defense then ETA blew up a load of civilians, those same people would be howling for its dismissal?
The problem with anti-war types is that they are generally perceived as being anti-war for the sake of being anti-war. The same cannot be said about the pro-war camp - after all, we are at peace most of the time!
With just one year of the DoD budget, famine could be erradicated forever in this planet, and you'd have enough spare change to build another shuttle and send a mission to Mars!
The food problem is nothing to do with food production, and it's nothing to do with money. The problem is political obstacles to distribution. Right now, for example, there is famine in Zimbabwe because their dictator Mugabe finds it easier to control the country if it's starving. The famines in Somalia and Ethiopia could be ended tomorrow if the local warlords could be persuaded to stop hijacking food shipments.
This situation is particularly interesting because it catches pacifists on the horns of a dilemma: allow the people to starve, or use military intervention to feed them?
Of course now the important thing is bombing Iraq because the stupid dictator there tried to kill someone's daddy *and* has huge amounts if oil...
You do know that the USA gets 7% of its oil from Iraq and 15% from Venezuela? If the war was about oil, it wouldn't be in Iraq!
I agree very much with this approach with some modifications, and here's why.
If one were to define a long-term goal for manned spaceflight, the only reasonable answer would be "to establish a long-term, self-sustaining human presence in space". Any other goal would not make sense in light of the overwhelming cost/risk advantages of unmanned flight.
The angst that a lot of people have over the Shuttle/ISS programs is that they don't seem to connect where we are today with this end-state goal. Costs per pound are not falling, and the ISS isn't really going to tell us anything we didn't already know from Spacelab and Mir.
So what should be next? I think the really tough nut is the "self-sustaining" part. I can see two broad scenarios:
- We develop self-sustainable environments in space first, and launch costs remain high. The tough challenge is to create a self-sustaining environment with little weight/volume. There are a number of possible routes to this. One could be a Biosphere2-like program (but managed differently) to explicitly figure it out. If that doesn't work, we could wait until technology allows humans to create more space-friendly bodies for ourselves, e.g., through genetic engineering or downloading a person's neural net into a silicon-based machine.
- We get lower launch costs first, and self-sustainability develops over time. If launch costs are low we could, in addition to sending supplies, export manufacturing technology to reduce the need for supplies. Over time, self-sufficiency could be achieved.
Now I don't think any of us knows which of these is the path of least resistance, so the logical course is to bet on both.So what would I do?
One of the reasons that many of the military projects continue is that we are afraid of losing the experienced people who build these projects.
The SeaWolf submarine is an excellent expample. We don't really need the new subs but if we don't build at least a couple of them, all of the engineers and craftsmen that build them will be out of a job and more on. Some of the needed skills will be lost forever.
It seems to me that we could use the space program to help to keep the people employed and the skills up to date. Keep bright minds and talented hands busy while getting the benefits of science and exploration.
I'm sure that I am making it sound simpler than it is but we could divert some of the money that is being used for unneeded military projects and maybe get something more useful out of it while still preserving the high tech skill sets that we need.
And you forgot to mention that the first accident was preventable. An engineering coverup.
It wasn't an engineering coverup. We studied this intensively in college, and the engineers who designed the O-rings knew the temperatures at the lauch site were lower than the O-rings were tested at. In other words, the engineers weren't quite sure what would happened, but from the data they had, their inital recommendation was not to launch.
They informed NASA about this, but the adminstration was pressed to launch. The Challenger launch had been delay for months due to weather and other conditions and because it was a highly publicized launch for sending up a civilian. Eventually, enough pressure was placed for the engineers to change their recommendation and the launch went. (If one subcontractor of the Space Shuttle recommends a No Go, the entire launch is scrubbed. The subcontractors who made the O-rings were the ones holding up the launch.)
Anyway, there were many factors that lead to the disaster of the Challenger, all of which could have been avoided.
The moon may well require a closed loop system but mars does not. There is water on mars and there is an atmosphere on mars ( largely C02 ) and the two combined with a source of power can be used to maintain living conditions. Go dig around and find info explaining the whole Mars Direct Concept. I would provide some but I find most people are more convinced if they take the time to find their own sources. Guy named Zurbin and 'mars direct' used as key words should give a good start.
Privitization is not a real option yet, though I agree NASA's organization needs to be better. Mostly I think they need to be seperated from the political process which surrounds the budget. NASA and its contractors spend so much time fighting for its budget money its impossible to focus on operations. Its like having to wory every year if your salary is going to be different. It makes it extrodinarily dificult to make any long term plans. NASA needs a stable budget that it does not have to worry constanly about. The larger the goals we want met the longer term the budget consistency needs to be. Not that there dosn't need to be some oversight but there are programs which start off knowing they are multi year ventures but they are asked to justify their expense EVERY YEAR... and experimental technology exploration does not lend itself well to to the budget justification processes so any program that meets with any difficulty especially early in its process is in danger of being cut. This leads to very very very short term near sighted goals. It also makes people very conservative in what they are willing to risk.
I don't ask you to be me. I only ask you not expect me to be you.