Chasing Moon Dreams: an exciting new material
Chasing Moon Dreams: an exciting new material
Team Phoenicia is an aspirant Google Lunar X Prize team. We have a spiral dev approach that made a new corrosive and cryogenic compatible composite.
Team Phoenicia is an aspirant Google Lunar X Prize team. We have a spiral dev approach that made a new corrosive and cryogenic compatible composite. Read more
Team Phoenicia is an aspirant Google Lunar X Prize team. We have spent the last couple years working on landers - a rocket - that could land on the moon and deliver a moderate sized rover. The first generation landers don't really need much help at this point. We have largely what we need there and will be flying shortly.
However, the first generation lander is built from aluminum and steel. It comes in at 220 lbs without fuel. Rockets live and die by their mass fraction - that is their ratio of everything other than fuel to fuel. If you can lighten the rocket's structure, the better its delta-V, change in velocity or in layman's terms, ability to go faster. We set about checking into using composites last September. It became very apparent that this was going to be tough /and/ expensive.
Cryogenic fluids, like the liquid oxygen that we are using in our rockets, are very rough on carbon composites. One of the reasons is that they are very, very cold. Carbon composites are made up of multiple layers of sheets of carbon and held together by a resin, a very fancy glue, sort of. The resin and the sheets have different thermal expansion ratios and this means that when they get very hot or very cold, the resin and the carbon fiber expand or contract at different rates. This causes the sheets to pull apart or delaminate. At very cold temperatures like that of liquid oxygen (-185 C or -301 deg F), this happens to an extreme which causes propellant tanks to fail.
To make matters worse, liquid oxygen is highly corrosive. And oxygen LOVES carbon, much to modern society's delight and horror.
With those two facts in mind, Team Phoenicia set out to create a carbon composite that would be both cryogenic temperature and corrosive compatible. It looks like we have succeeded.
After doing some ugly chemistry and a bit of the out of the box thinking, we successfully made four testing coupons, ie small samples. We then gave them a treatment that made them compatible with corrosive substances. After testing and work, we ended up with two final samples that we could use for testing. And test we did.
We spent since March testing the samples. We did thermal cycling tests mainly, where we would place the coupon in liquid nitrogen, let it cool to liquid nitrogen (LN2) temperatures for five minutes, remove the sample, let warm it to 30 C (86 F), and then take measurements. The samples were checked for cracking and expansion (which would indicate delamination). After over 80 thermal cycles, no delamination was detected. One of the samples was then sliced horizontally, for visual inspection. No delamination was detected again.
In contrast, a control sample of standard carbon fiber was also placed in LN2. After a single thermal cycle, delamination was detected, visually, through expansion, and through cracking.
What We Need Help From Kickstarter For
Now, we need to take the next step. It's /expensive/. We need to make six inch spherical tanks from our "secret sauce" carbon composite. There are multiple steps here.
1. We are making the flanges that will allow us to connect the tanks to hoses to fill, pressurize and empty the tanks. We have acquired the stainless steel we need and we will snap a couple pictures of the work in progress by our team's machinists for people to see over the next few weeks.
2. We have also mostly paid for the molds for the spheres. This was done with some professionals in the composites industry. We need to finish paying for them.
3. Then we need purchase another batch of resin.
4. Then we need to deliver the flanges to the composites guys doing the lay up and have them do the lay up. They will deliver to us 4 tanks.
5. We then treat the spherical tanks with our corrosion protection.
6. We do testing.
6a. We will start with a burst test. We will purposefully pressurize the tank until it pops from pressure. This will verify the tank has been made to specification.
6b. We will move to thermal cycling: load the tank with LN2, let it sit, and then unload it. We will be checking for delamination and cracking here.
6c. We will follow-up to then pressurized thermal cycling: the same as previous, but the tanks will be pressurized with helium up to our desired pressure while loaded with LN2.
6d. We will then put conduct a test with the tank while loaded and pressurized on a shaker table to verify that the tank can handle the expected vibrations with a rocket.
What Kickstarter Will Pay For
KS backers will be paying for...
Finishing the molds: $1,000.
The resin: $1,000.
The layup: $2,000.
The treatment, including chemicals and some lab equipment: $4,000.
Access to the shaker table: $1,000.
Why Do This?
First, this is a potentially revolutionary material. We say potentially because the tests are unfinished. However, this is one seventh the weight of aluminum for the same strength. The current tanks of the first generation lander are 28 lbs for the liquid oxygen tanks. If we redid them in this composite? 4 lbs.
So, yes, its patentable. We think. We're in the process of filing a provisional patent as we write.
That's the second reason: help the underdogs out race the big guys.
Word has leaked out from where we are doing our testing about what we are doing. We have been approached by two composites companies about getting samples. This means the clock is now ticking: once someone knows something is doable, even if they don't have access to the samples, they have a lot more resources on hand than we do. With your help, we may still beat them.
More Info On Us
Main Website: http://www.teamphoenicia.org
Youtube Channel: http://www.youtube.com/user/teamphoenicia
A Column About us in the San Jose Mercury News: http://www.mercurynews.com/mike-cassidy/ci_15177378
- (24 days)