

Any way to "hack" the Google Lunar X Prize? - ryanwaggoner

Warning: This question is likely so stupid that I'm going to wish I had posted it anonymously to avoid ridicule, but what the hell :)<p>I find the subject of space exploration and colonization fascinating, but the incredible costs for access to space seem to be a nearly-insurmountable obstacle to true progress in these areas.  I've recently become interested in the Google Lunar X Prize and started looking at the teams who are competing.  While these teams are probably going to accomplish some amazing things, I suspect they're going to do it on the back of tens of millions in funding...is that truly the only way?<p>I guess my question is something like this: is there any <i>theoretical</i> way to win something like the Lunar X Prize for $1 million?  $100k?  $10k?<p>Here are some ridiculous thoughts that I've had:<p>1. Using high-altitude balloons to cut down on launch costs.<p>2. Going small.  Very small.  Like a pound or two for the rover.  Maybe smaller.<p>3. Getting the cost low enough that you can launch multiple missions, knowing that most will fail.<p>4. Travel to the moon over a period of months...would this reduce launch difficulty?<p>I'm sure I'm probably missing the scale of the problem here, and perhaps the simple laws of physics dictate that there's no cheap solution that we know of yet.  Or is there?
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mkn
If your rovers were small enough, you might be able to make a gun-launched or
gun-assisted scheme work. If you could engineer your probe/launch vehicle to
withstand 20 Gs, for example, a linear acceleration at that level would get
you to Mach 1.2ish in 400 meters or so. You come out of the barrel cleanly in
ramjet territory and, what's better past the point where your shock wave
angles are highly dependent on Mach number. You could start out in subcritical
mode for the engine and progress through critical and supercritical, buying
hardware simplicity with some loss of efficiency. You might even be able to
shed some of the diffuser cowling in stages at the lip for a Q&D variable
geometry engine. By the tme you hit M = 5-7, you'd probably be out of the
atmosphere and would have to switch to rocket mode anyhow. Your mass fraction
for the booster stage would be pretty amazing because you'd shaved 2000-2500
m/s off your delta-V with the gun/air-breathing phase. (That matters a lot to
the rocket equation. I'll leave it as an exercise for the reader to work out
the actual benefit.)

The limiting factors here are obtaining a guidance and control system that is
small enough to fit down your (admittedly large bore) low-pressure launch gun.
Also, your gun would have to be pretty dang straight or your vehicle would
have to be wrapped in a vibration-absorbing sabot.

The benefits are: 1) Once you have the gun, you can launch as many as you
like; 2) Mass fraction as mentioned above; 3)The possibility of production-
lining launch vehicle construction.

Not that I've given this any thought.

BTW, Bruckner et. al. at the University of Washington have been working on a
ram accelerator, a type of launch gun, for years. The only thing slowing them
is funding. They omit an airbreathing stage in favor of obtaining all the
Delta-V in one shot, subjecting the payload to 700-1e3 Gs.

~~~
aaronblohowiak
Yea, building a massive electromagnetic riffle along the slope of a mountain
in a third world country to repeatedly launch vehicles into space has been on
my todo list since i first read "the moon is a harsh mistress."

~~~
JabavuAdams
Worked out great for Gerald Bull

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RKlophaus
Had the privilege of hearing a presentation by Brian Binnie, the test pilot
for Scaled Composites (<http://scaled.com>) shortly before they won Ansari
XPrize back in 2004.

His description of their team sounded like the ultimate group of hackers. And
his description of their process sounded exactly like the questions you ask
above... discarding all preconceived notions, how do we make this happen in
the cheapest, simplest way possible?

He also advised that teams adopt a mantra of "Question, don't defend." In
other words, it's more important to realize that something is wrong and get it
fixed than to assign blame or respect egos.

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ph0rque
Not a stupid question at all. I remember Cringely writing something about
hacking that particular prize, as well... I'll add a link once I find it.

~~~
ph0rque
This is the link, although you'd have to go back a couple to get the beginning
of the story:
[http://www.pbs.org/cringely/pulpit/2008/pulpit_20080530_0049...](http://www.pbs.org/cringely/pulpit/2008/pulpit_20080530_004991.html)

~~~
streety
That's a little disappointing.

It starts out well:
[http://www.pbs.org/cringely/pulpit/2007/pulpit_20070927_0030...](http://www.pbs.org/cringely/pulpit/2007/pulpit_20070927_003043.html)
[http://www.pbs.org/cringely/pulpit/2007/pulpit_20071214_0036...](http://www.pbs.org/cringely/pulpit/2007/pulpit_20071214_003618.html)
Then goes downhill: <http://spacefellowship.com/News/?p=4718> . . . and
culminating in the link your posted.

They could really do with pointing a few more links to their website:
<http://www.teamcringely.org/>

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zain
I had a crazy idea too, and I'll probably get ridiculed, but what the hell.

I think it is fairly straightforward to get something tiny to the moon. The
challenge comes in making it broadcast back to earth. For wireless
transmissions, you need considerable bulk and you add a lot of cost.

Wouldn't it be cool if, instead, it was connected to earth by a ridiculously
long insulated wire? Then you might even be able to cut down the size to well
under a pound for the rover itself (not including the fuel needed to get
there). It shouldn't have problems transmitting as long as the wire is
insulated well enough, right?

Some back-of-a-napkin calculations lead me to believe that you wouldn't need
more than 60 cubic miles to store enough wire to reach the moon (200,000 miles
long, 1 inch thick).

what do you think? flame away :)

~~~
gravitycop
_Wouldn't it be cool if, instead, it was connected to earth by a ridiculously
long insulated wire?_

<http://en.wikipedia.org/wiki/Specific_strength>

 _Another way to quote specific strength is breaking length, also known as
self support length: the maximum length of a vertical column of the material
(assuming a fixed cross-section) that could suspend its own weight when
supported only at the top. For this measurement, the definition of weight is
the force of gravity at the earth's surface applying to the entire length of
the material, not diminishing with height._

According to that article, the breaking length of steel is 26 miles, of kevlar
256 miles, and of carbon nanotube 4,716 miles.

~~~
netcan
Would that (the longer tube) take into effect the diminishing force of gravity
on each additional mile?

~~~
gravitycop
_Would that (the longer tube) take into effect the diminishing force of
gravity on each additional mile?_

No. From the description I quoted:

 _For this measurement, the definition of weight is the force of gravity at
the earth's surface applying to the entire length of the material, not
diminishing with height._

~~~
netcan
Sorry. Stupid.

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JabavuAdams
Join the a-rocket mailing list for extremely high SNR discussion:
<http://www.arocketry.net/forum.html>

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lallysingh
Well, there's also the subproblem approach: (Note, I'm completely speaking out
of my ass)

\- Launch a string of relays between orbit & the moon. They may only work once
a month, but that just means you have to have the judges there that day :-)
Each one can be a control board, radio, and solar panel. Swarm satellites, I
think they were called, only in a straightish-line.

\- Make the actual lander dead, dead, dead simple. Like forward & turn-in-
reverse RC car simple. Make it small & rugged, but put little/no control
electronics onboard. Power (unless you can beam it in from a near-moon
satellite into a battery pack -- it's fine to let the rover sit around 29
days, 23 hr, 45 min of the month, to let it charge), and receiver(s) to
control the motor(s).

\- Data transmission could be a controllable mirror, and a relay with a good
camera!

But I guess this all really depends on another question: what's the cost to
weight function? Purely linear? Is it cheaper to do two launches of weight W
instead of one launch of weight 2W, over a minimal value for W?

If a launcher for a standard size object can be the primary cost of the
system, we could launch relays and landers in swarms and leave the big money
for the launcher. 10% success rate? Launch 15 to be sure.

Also, one situated between three high-altitude balloons would look pretty
sweet.

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AndersFeder
Many interesting thoughts here. A few comments:

It is very difficult to make a launch vehicle powerful enough of your own. No
matter how you do it, you will need a good deal of propellant for lunar
transit, descent and landing. This means the launch mass is bound to be
relatively high. Also, your launch vehicle has to be capable of reaching
orbital velocity (approximately mach 22). Even the best amateur rockets, to my
knowledge, have only achieved around a fourth of this velocity, and that is
with no payload.

Ion drives aren't practical for a mission like this for a number of reasons.
For a full discussion of why, please see this article:
[http://openspacex.org/2008/10/06/escaping-the-grip-of-
mother...](http://openspacex.org/2008/10/06/escaping-the-grip-of-mother-
earth/)

If you are interested in having your ideas seriously considered, please
consider joining Team FREDNET, an open source team in the Google Lunar X
PRIZE. Most everyone are welcome: <http://www.teamfrednet.org>

------
brentpenman
What's the breakdown of costs... my intuition is that the biggest number is
from launch (especially fuel) but am I wrong?

~~~
mindviews
Yes, the launch is the real cost driver for space economics. Launch costs
alone are in the neighborhood of $10,000/kg for large American providers and
somewhat less in other providers/countries. I believe no one has come close to
the $1,000/kg mark yet.

Because launch is so expensive, people then spend a lot more money making sure
the payloads are ultra-reliable (launching a replacement is just too
expensive). Because costs are so high, there isn't enough business to really
get good economies of scale (yet...go SpaceX!) - so a lot of money goes into
design and testing of new rockets that will only see 10-100 units built.

As for launch itself, fuel is pretty cheap - turbopumps are expensive. It is
the high-precision machining of parts that ends up costing you. If you can
reuse the hardware, then you get savings for future launches and everyone is
happy.

------
dmoney
Smaller is probably better. I read something in Forbes (or maybe Fortune Small
Business) about a guy who is building small rockets capable of launching
things like science experiments and people's ashes into space. He's apparently
one of the first clients of Spaceport America.

I don't think they were capable of deploying satellites or additional stages,
but perhaps a similar design could.

Another thing to consider would be having the planetary transmitter be a
separate module from the rover, allowing a smaller rover, and a smaller
lander. The rover would then just need a less powerful radio. The more
powerful transmitter could be landed separately, or even remain in orbit.

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trapper
High altitude balloons are great fun. I am working on a rocket launch
mechanism for one in my spare time. Costs are really low.

<http://www.hobbyspace.com/NearSpace/index.html>

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JabavuAdams
Thermal protection and heat dissipation will most likely be a hard problem.

Getting a lander to survive into the lunar night is a big challenge in its own
right.

If it can't survive the night, that places other constraints on the mission.

~~~
cool-RR
Why is it hard to survive the night? Because of the coldness? Why would the
coldness be a problem? Even if the machine couldn't operate in such a low
temperature, can't it just hibernate until day?

~~~
JabavuAdams
So ... IANARS (I Am Not A Rocket Scientist) ...

The lunar night is about 2 weeks long. The night-time surface temperature is
about -230 C to -150 C.

I'm not sure how long it would take a lander to cool down at local sunset, but
it might be pretty fast. That kind of cooling can create stresses and actually
break mechanical connections or electrical components.

It's a lot warmer at about 1 m under the surface, but you have to get there
somehow.

------
cvg
What if we rethought the design of the "rover" to make it smaller and the
whole launch mass less? I don't think there's a requirement for a four or even
three wheel rover. Instead, we could use a clear double inflatable ball with
an instrument package and a motor inside. This allows for a < 10lb/5kg rover.
We could pack dozens of these in several rockets to the moon. Redundancy would
be in our favor. Kind of like moving from big-iron servers to farms.

This is my inspiration for the double inflatable ball:
<http://www.hammacher.com/publish/72182.asp>

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tiki12revolt
Employing high-altitude balloons to cut down on launch costs is potential
feasible, as traditional launches can run into the tens of thousands of
dollars (or more) per lb.

One potential problem with going small on the rover end is that the prize
stipulates that the rover must travel a prescribed distance on the lunar
surface, and going too small will make traversing distance a much greater
obstacle that it already is. Additionally, how would one power the antenna
necessary to communicate with earth (I am thinking specifically of battery
power only, and I think it would in and of itself weigh more than a pound)?

~~~
gravitycop
_Employing high-altitude balloons to cut down on launch costs is potential
feasible_

How would high-altitude balloons reduce launch costs?

~~~
stcredzero
Not by much. Most of the energy cost of a launch to Earth orbit involves
getting to orbital velocity. Getting an object that high is pretty easy by
comparison.

(Get out your physics textbook and compare the kinetic energy of something
going Mach 24 to the potential energy of something dropping 100 km.)

I'd expect a mistake like this from a high school student or a freshman. If
you're not clear about this, then you have a perhaps a bit of homework to do
before posting questions about space to a social news site that prides itself
on informed, intelligent discussion.

Perhaps start with Zubrin's _Entering Space_. Any number of books about the
space program will do as well.

~~~
wlievens
I don't think a person should "do his homework" before asking a mere thought-
provoking toy question. However naive the question, it has potential for
informed, intelligent discussion.

~~~
stcredzero
Not if you're off by an order of magnitude!

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mhb
More accessible challenges can be found here, including a tether for a space
elevator and an astronaut glove.

<http://news.ycombinator.com/item?id=442634>

------
Tichy
There has to be a way, I used to think about this, too...

Not sure if balloons get you that far, though. I think mostly you can avoid
the friction of the air to some extent, but if I remember correctly, the
altitude where you still have air to float a balloon in is only a tiny
fraction of the stationary orbit altitude.

Just a thought right now: what about nanobots? Perhaps something could be made
so tiny that it doesn't even fall down... kind of like a balloon without a
balloon. Not sure if it would still be workable without an atmosphere...

~~~
jsmcgd
Yeah unfortunately the altitude isn't really the problem. It's high speeds
that you want. The altitude just gets you away from the atmosphere which will
stop you achieving the high speeds.

~~~
Tichy
Maybe since fuel isn't so expensive it isn't such an issue anymore, but I
really like the idea of somehow powering a vehicle with solar power. The nice
thing about velocity is that without friction, you can get really fast over
time even with relatively weak acceleration. No idea whatsoever how to
accelerate a rocket with electricity alone, though... Is it even possible? I
think NASA has some models, but for long distance stuff...

~~~
jerf
Lookup "Ion Drive". If you end up on a Star Wars site, you've missed; there's
a real such thing that has flown in real space.

You can't launch on an Ion drive, though. (Even if you made it powerful
enough, that would mean irradiating the entire launch area with instantly-
lethal radiation, not a terribly social thing to do.) The way to a solar-
powered launch is that you use solar power to create the rocket fuel, which in
the simplest case is simply cracking water into H and O.

Solar panels are orders of magnitude away from being able to launch themselves
in real time. Take a solar panel, compute its mass, compute how much energy it
can generate in a day, convert that to potential energy in Earth's
gravitational field, and you'll get a sense of the maximum speed a panel could
possibly rise with perfect conversion of energy to height (which we have no
idea how to do anyhow). I haven't done the math but if you get a rise rate of
more than a few inches a second during the brightest part of the day I'd be
surprised.

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ivankirigin
You can't broadcast from something that only weighs a pound or two.

The launch is by far the most expensive part, so going multiple trips isn't
really an option.

The folks who won the Urban Grand Challenge have a great approach:
<http://astrobotictechnology.com/>
<http://www.youtube.com/user/AstroboticTechnology>

~~~
froo
This might sound strange, but instead of radio broadcasts, what about the
possibility of doing broadcasts with bursts of light utilising lasers?

I guess my thought is based off the old idea that you could intercept data off
a modem by reading its LED at some considerable distance - and just upscaling
it with more powerful tech.

<http://applied-math.org/optical_tempest.pdf>

I realise that it would be near impossible to have the Earth visually see the
transmission on a consistent basis, so what about a satellite in earth's orbit
that essentially matched the moon's orbit, creating some kind of relay
station.

~~~
jws
Or better yet, use a passive element on the moon side. There are optical
reflectors up there from moon missions that people can bounce (large) earth
based lasers off of. Imagine one of those with a single LCD film over it. You
can then selectively polarize the reflected light at virtually zero power use.
It won't be a fast bit rate, the LCD could to 100bps easily, but I wonder what
the atmospheric scattering does to the wavefront.

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markessien
If you really want to attempt this, the correct approach would be to approach
the problem from the perspective that gravity is the force you have to defeat.
Find a way to reduce this force significantly and you may find a cheap
solution.

For example, magnets defeat this force. Look for things that can work against
gravity even in the absence of air.

