Returning To The Moon -- Cheap And Simple

I am aware that simple is not the same as easy. Let me say that up front. But simplicity has many advantages. First, an update on the Google Lunar X-Prize. See Google's Lunar X-Prize Gets Real.

Today the organizers of the Google Lunar X Prize announced the final roster of teams competing in a $30 million race to the lunar surface. And much to their surprise, 29 teams have signed on to the mission...The terms of the contest are easy, but succeeding is hard. A private firm has to send a robot to the moon. After it gets there, the bot will travel 980 feet and transmit video, images and data back to the Earth. The prize: $30 million...The Lunar X Prize's time limit expires in 2015.

Here is the background on how to do it: Hydrogen Gas Cannons Could Launch Payloads To Orbit

Light-gas cannons work almost like you’d expect a really, really big gun to work: at one end inside of a long tube a gas, hydrogen, helium or methane, is pressurized to an extreme pressure, 15,000 PSI...Hydrogen is used because of its lightness. Since a projectile can’t go faster than what’s pushing it along inside a cannon, the lighter gas – which can travel quicker – allows for a projectile to be accelerated to incredible speeds, in excess of 13,000 miles per hour (21,000 km/hr)...a system that is capable of launching 2-pound (0.9 kg) payloads into space will be designed. The cost of this cannon, Hunter estimates, will be around $10 million and take two years to get rolling. [The 2lb capability launcher] is actually tailored to a small niche, which is the Cubesat community. It makes sense because we can “G-harden” cubesats...

Now here is the way to do it. Launch a whole collection of 2 pound payloads. Launch cost is pretty trivial, the main cost here is the infrastructure. So what you do is, launch your lunar vehicle in 2 pound chunks -- like Legos. Also launch 2 pound fuel containers. Some of the 2 pound "chunks" will be robotic "assemblers", some will be cameras to see what is going on. They will run from solar power and be controlled from Earth. The assemblers put together the vehicle that will transport the lander to the moon, and the lander -- or landers. Because see, the transport then becomes a trans Earth-Moon shuttle. It just runs a lander to the moon, drops it off, orbits the moon as needed, and returns to Earth orbit for more fuel and to pick up another lander.

See? Very simple. Now I am very aware that simple does not equal easy but this concept is very simple and will work because of its simplicity.

(1) Building the gas cannon? Simple.
(2) Launching 2 pound payloads? Simple.
(3) Doing Telerobotic Lego-like assembly in orbit? Simple.
(4) Sending vehicle to lunar orbit from Earth orbit? Simple.
(5) Landing a small robotic lander on the moon? Simple.
(6) Returning the transport vehicle to Earth orbit? Simple.
(7) Docking with the next assembled lander and refueling in orbit? Simple.

Every one of the above steps is scientifically sound (we know the math, the physics, and the chemistry). Every step is solid engineering (we have already done every one of these things in one way or another.

Cost -- dirt cheap compared to current space travel. Dirt, dirt cheap. And boy, you want to start a new industry, excite high school and college kids and get them motivated to learn science and engineering and robotics etc? Do this.

Plus -- it will be SO cheap it can be done 100% with donated money, time, and corporate advertising. Treat it like NASCAR racing for the corporate ads, involve the gamer community for the telerobotic operators, get college kids to write the code, get some deep pocket rich guys (Gates, Trump, etc.) to kick in seed money in exchange for the bragging rights -- I tell you, this is feasible.

At the very end, at the Nascar mention...I suddenly pictured a craft..floating in space...With a "Mountain Dew" Logo on the side..

Great thread!

Many people just cant grasp that hey...we did this DECADES ago. I mean, we have computer contestants on game shows, but we cant cheaply make it, and possibly colonize the moon?

sounds great when do we get started, it could be all be designed and built here over ATS, if everyone with skills set to and built small parts of what is needed it could be all posted to the various launch sites and checked for quality before loading onto the cubes, just another idea maybe...

Please forgive my pessimism, but I can't see much point in going to the moon.
I mean, last time we went (if indeed we did!:lol it cost billions, and we bought back some dust.

"We've been to the moon at billions expense, here is some dust."
Thanks. Thanks for the dust.

Even if we go there to colonize it, we will just f##k it up like we have the earth!!

Sounds like a great idea, with a $30M prize, companies have an incentive to compete, and generate spin-offs in the process. This should be the kind of thing done in other areas as well, such as alternative energy.

Regarding this "mission" specifically, the first step is the last step. If the specifications are to have a vehicle that needs to go 980 feet, and transmit video, then how light and small could such a robot be? If such a thing could be reduced to a mere 2 pounds (for example), would it be G-resistant enough at that weight, to survive a cannon? If not, then how much size and weight would it have to "grow" to harden it enough for that scenario? If several "shots" were required, then how to assemble in space? How many more shots might that add up to?

Or, perhaps old-fashioned rocket tech could be used? Or a weather balloon lift, for part of the journey?

Because there is no real "rush" to get there, once in space, perhaps even relatively tiny propulsion, along with sling-shoting perhaps, could be used to get there over a period of months, and with reduced speed, less braking would be required, less fuel, etc., once it reached the moon, perhaps gently entering the moon's gravity an an angle.

Depending upon entry speed, perhaps a simple foam inflation envelope around the lander would be enough to ensure a safe "bounce" landing, considering how small it might be, and the reduced gravity of the moon.

If the above scenario was determined to be the most cost-efficient, then that scenario would dictate a landing site that yielded the highest probability of success. Is there a long swath of terrain that had the fewest ugly rocks to collide with, as it bounced along for miles before stopping? If so, would the dust/dirt that the vehicle finds itself in when it came to rest, be able to crawl across it easier, or would it prove more difficult, than other types of dust?

Contingencies. Would it make more sense to "add" capability, based on probabilities? For example, if the best case scenario only seemed to indicate a 50% success, what could be done, added, to bring that probability up to something better than a coin-toss? In other words, if this mission was going to cost $3M, to perhaps get $30M, and it failed half the time, wouldn't it be better to spend say $5M, and be successful 85% of the time?

There are a LOT of variables in something like this, and your imagination ca run away with you. It would be "fun" to have some extra millions laying around to do something like this, assemble a team, etc.

I think though that I will get a great deal more enjoyment out of an underdog succeeding. Sure, Sir Richard Branson might beat them all to it, but wouldn't it be nice if some humble Aussie or Brazilian, living in the sticks, surprised everyone, raising a few hundred thousand in donations, and kicking all the corporate butts?

Even more fun, the video vehicle lands right next to something we're never supposed to see! And somehow, the image gets through!

Yeah, now I'm really dreaming.

JR

Originally posted by SunSword
Here is the background on how to do it: Hydrogen Gas Cannons Could Launch Payloads To Orbit

Light-gas cannons work almost like you’d expect a really, really big gun to work: at one end inside of a long tube a gas, hydrogen, helium or methane, is pressurized to an extreme pressure, 15,000 PSI...Hydrogen is used because of its lightness. Since a projectile can’t go faster than what’s pushing it along inside a cannon, the lighter gas – which can travel quicker – allows for a projectile to be accelerated to incredible speeds, in excess of 13,000 miles per hour (21,000 km/hr)...a system that is capable of launching 2-pound (0.9 kg) payloads into space will be designed. The cost of this cannon, Hunter estimates, will be around $10 million and take two years to get rolling. [The 2lb capability launcher] is actually tailored to a small niche, which is the Cubesat community. It makes sense because we can “G-harden” cubesats...

Now here is the way to do it. Launch a whole collection of 2 pound payloads. Launch cost is pretty trivial

I don't think the cost of a rocket motor for each 2 lb payload is trivial, and you haven't explained how you'd get it into orbit without the rocket motor (with the gun alone). From your source:

Critical to getting the payloads into orbit is the use of a single-stage rocket attached to the payload projectile.

The Wiki article explains a couple of reasons why you need the rocket motor even if you use the
Space gun:

In the HARP Project a U.S. Navy 16 inch (406 mm) 100 caliber gun (40 m) was used to fire a 180 kilogram slug at 3,600 meters per second, reaching an apogee of 180 kilometers, hence performing a suborbital spaceflight.

However, a space gun has never been successfully used to launch an object into orbit.

Atmospheric drag also makes it more difficult to control the trajectory of any projectile launched, subjects the projectile to extremely high forces, and causes severe energy losses that may not be easily overcome. A space gun with a "gun barrel" reaching above the lower troposphere, where the atmosphere is most densely packed, may mitigate the issue.

A space gun, by itself, is generally not capable of placing objects into stable orbit around the planet, unless the objects are able to perform course corrections after launch.

If acceptable solutions to these fundamental issues could be achieved, a space gun could offer access to space at an unprecedented low cost.

I don't see anything in your links saying that the problems mentioned of atmospheric drag and the need to have a rocket motor have acceptable solutions, in fact your source says it still needs a rocket motor.

See? Very simple. Now I am very aware that simple does not equal easy but this concept is very simple and will work because of its simplicity.

Rocket science is neither simple not easy and nobody has ever demonstrated a space gun can put an object into orbit without a rocket.

(1) Building the gas cannon? Simple.
(2) Launching 2 pound payloads? Simple.
(3) Doing Telerobotic Lego-like assembly in orbit? Simple.
Every one of the above steps is scientifically sound (we know the math, the physics, and the chemistry). Every step is solid engineering (we have already done every one of these things in one way or another.

No, we have never put an object into orbit with a space gun alone. I'm not saying it's impossible, only that neither you nor your source has demonstrated a viable concept for doing so.

But it's nice to see some creative thinking nonetheless.

When you get into the details, you might find that one of the solutions to the atmospheric drag problem is making the gun so long the barrel end is above the densest part of the atmosphere. Constructing such an extraordinarily long gun is anything but simple (ask a civil engineer about this), and I doubt you could put it on a boat like they are suggesting.

I also question whether it's simple to ruggedize something to withstand those kinds of G-forces. It might be possible but I'm not aware we have ever successfully demonstrated this...note the HARP test just fired a slug, not too much need to ruggedize that against G forces.

reply to post by Arbitrageur

Yes a projectile fired from a gun would either achieve escape velocity and never return (highly unlikely the gun would be powerful enough to do this) or the projectile would fall back to earth. If nothing else happened. However it is not necessary to use a rocket engine for "something else to happen". Essentially what you need is a "catcher's mitt". Because you are going to fire a whole bunch of these Lego-like 2 pound projectiles, it is necessary for them to be gathered into one location for assembly. Therefore you would fire them such that when the projectile is at or near apogee it would be captured.

So you have a catcher's mitt in orbit. When it is in the right position the gun fires. The projectile intersects with the mitt, the mitt catches the projectile. After each projectile is captured it is grabbed by a small robot and transferred to the assembly area. Note that some of the projectiles are fuel containers. Some of these fuel containers will be used for the earth-lunar transporter, some for the lunar landers, but some will be used by the mitt assembly itself. This is necessary for it to maintain a stable orbit since it will keep catching these 2 pound projectiles, thus altering its momentum.

The rate of firing of projectiles is thus dependent both upon how fast the gas pressures in the gun chambers can be re-pressurized AND upon the timing of the orbit of the mitt. (Not counting maintenance time for the gun.)

So you see, it IS possible for a gun to be used for a launcher, AND to not to have to require each projectile to carry its own fuel to achieve a stable orbit. Because the projectiles are not trying to achieve a stable orbit. Just to reach a certain point at a certain time at the appropriate speed. And getting slammed into the mitt is no big deal for the projectiles since they have to withstand far higher acceleration when being fired by the gun itself. So the only key is making sure the mitt is tough enough to absorb the impact and -- again, that is an engineering problem.

Originally posted by SunSword
So you see, it IS possible for a gun to be used for a launcher, AND to not to have to require each projectile to carry its own fuel to achieve a stable orbit.

OK, interesting concept, but it has a couple of issues. The "catcher's mitt" will reach a higher orbit every time something leaving Earth slams into it, right? That may not be a fatal flaw if you start out with a low enough orbit and don't fire too many things into it. But if you want the
"catcher's mitt" in a stable orbit it would need a fuel supply to make compensations in it's course for all these things projectiles striking it.

But you didn't address the atmospheric drag issue. Don't you still need a rocket engine to overcome atmospheric friction to get it to the catcher's mitt? And if you think it's possible to overcome atmospheric friction with a space gun, please provide a source since the source you provided said a rocket was needed even with the space gun.

Thanks.

Originally posted by Arbitrageur

Originally posted by SunSword
So you see, it IS possible for a gun to be used for a launcher, AND to not to have to require each projectile to carry its own fuel to achieve a stable orbit.

OK, interesting concept, but it has a couple of issues. The "catcher's mitt" will reach a higher orbit every time something leaving Earth slams into it, right? That may not be a fatal flaw if you start out with a low enough orbit and don't fire too many things into it. But if you want the
"catcher's mitt" in a stable orbit it would need a fuel supply to make compensations in it's course for all these things projectiles striking it.

But you didn't address the atmospheric drag issue. Don't you still need a rocket engine to overcome atmospheric friction to get it to the catcher's mitt? And if you think it's possible to overcome atmospheric friction with a space gun, please provide a source since the source you provided said a rocket was needed even with the space gun.

Thanks.

Yes -- that is why the catcher's mitt also uses some of the fuel cubes that are launched for its own purposes -- I mentioned that. This will enable a catcher's mitt to maintain a stable orbit.
As for atmospheric drag, the ISS orbits between 300km and 450km. Considering that the US Navy launched a 180 kilo projectile to 180km simply using a 16 gun in the early 60's, and I am talking about launching a 1 kilo projectile today with a larger longer gas gun that will achieve higher acceleration -- I do not think this is an issue.