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2011-08-29

Sugar Shot Weekly Activity Report: August 22-28, 2011‏

Craig Peterson has made significant progress in fabricating the "vacuum chamber" that will be used for testing our avionics at simulated altitude. Craig has obtained a length of 6" PVC pipe, end cap, and aluminum end plate. As well, Craig has purchased a two-stage vacuum pump capable of evacuating the chamber to the extent required. Richard has ordered a precision vacuum gauge (from Omega) which is being shipped to Craig.

Photo of PVC pipe for vacuum chamber and vacuum pump (in box):
Photo of removable aluminum end plate (stock):
(photos courtesy Craig Peterson)

Richard has been working on the design of a wooden "transport cradle" that will be used to transport the motor chambers to the workstation and to the test stand. Each fully loaded chamber will weigh an estimated 152 lbs (69 kg) and will require a minimum of 4 persons for transport.

The Sugar Shot to Space program has received a major "shot in the arm"...our primary DSS sponsor Markus Bindhammer announced that he is donating $10,000 USD for the eXSShot project! This is fantastic news that takes us one step closer to achieving our goal of reaching space using the power of "sugar". We also welcome Markus as our newest member of the SS2S team, in the role of "General Project Support". The Team Selene logo will be phased out, per Markus's request. Thank you so much, Markus, for your generosity and for your belief in our team's ability to achieve the remarkable.

Hexaphenox - Celluloid composite propellant

Celluloid is a highly flammable cellulose nitrate-based plastic. A typical formulation of celluloid contain 70 to 80 parts cellulose nitrate, nitrated to 11% nitrogen, 30 parts camphor, 0 to 14 parts dye, 1 to 5 parts ethyl alcohol, plus stabilizers and other agents to increase stability and reduce flammability. Celluloid is still common used in table tennis balls.
I had a few table tennis balls at home, so I cut one in half and took a whiff. I smelled camphor . I cut 3 balls in small pieces and desolved them in 50ml acetone, stirring the solution from time to time. It takes around 2 hours till the celluloid is completely disolved. I mixed then 5g of the thick celluloid solution with a prepared fine powdered mixture of 8.5g KClO3, 1.5g hexamine and 1g phenolphthalein and formed a snake on coated baking paper. The picture below shows the dried propellant and the celluloid solution (it is yellow because the table tennis balls were colored yellow):

2011-08-28

Potassium nitrate/sugar propellant improvement

We know that hexamine can not be oxidized with KNO3 but with the additive phenolphthalein. My simple assumption was now that phenolphthalein could improve the combustion behavior of potassium nitrate/sugar  (sucrose, sorbitol etc.) as well, so I made a quick comparison test of 2g KNO3/sucrose and 2g KNO3/sucrose (65:35 ratio) with some phenlphthalein added:


The mixture with the added phenolphthalein was easier to ignite and burned much quicker. The melting points of sucrose (185–186 °C) and sorbitol (110–112 °C) are far lower than the melting point of phenolphthalein  (260 °C), so phenolphthalein and KNO3 could be both dissolved in dry heated sugar.


Update August 29, 2011 

I just found a first source (The chemistry of fireworks by Michael S. Russell) where it is mentioned that phenolphthalein was used to enhance the burn rate of gun powder. Page 42: "...together with an organic fuel, known as phenolphthalein, which is said to enhance the burn rate."
I was not aware of this. I found the effect of phenolphthalein by myself without this knowledge.
Another source (Black Powder Manufacturing, Testing & Optimizing by Ian von Maltitz) says on page 27: "Phenolphthalein has been used as a charcoal substitute [for black powder]. Its use hasn't gone much beyond the experimental stage. This is possible because phenolphthalein is very expensive when compared to charcoal..."

Neither phenolphthalein and KNO3 nor phenolphthalein and KClO3 are combustible without a second fuel. 

2011-08-26

Hexaphenox - PVC adhesive based composite

A polyvinyl chloride (PVC) adhesive for joining PVC pipes consisting essentially of about 10 to 22 wt % PVC resin and about 2 to 25 wt % acrylic resin, a high vapor pressure solvent consisting essentially of about 10 to 50 wt % tetrahydrofuran and 0 to about 40 wt % methyl ethyl ketone, a low vapor pressure solvent consisting essentially of about 10 to 35 wt % cyclohexanone and 0 to about 35 wt % N-methyl pyrrolidone and up to about 5 wt % of at least one component selected from the group consisting of pigments, fillers, and thixotropic agents.
First experiments showed a very vigorous combustion of hexaphenox with PVC adhesive as a binder, compared to binders like polyvinyl acetate, epoxy or rosin:


After the successful test with 10g hexaphenox, 60g hexaphenox with 20g fresh PVC adhesive were mixed and casted into a 30mm ID PVC tube with a 10mm dia. round core. The casted propellant plus PVC tube had a mass of 92g. The propellant was left over night to set and came then the next morning for 2 hours at 85  °C into the baking oven to remove rests of the solvents. A mass reduction of 10.5g was observed. The propellant turned slightly brown at the end of the drying process.


Static test firing:



The mixture in the above video was not stoichiometric. A mixture of
  • 78 % w/w KClO3 
  • 8 % w/w hexamine
  • 5 % w/w phenolphthalein
  • 9 % w/w PVC adhesive (dry, whithout solvents)
is close to stoichiometric (nearly no resedues left after combustion).

Combustion of 7g nearly stoichiometric high power hexaphenox mix:


The tile was molten and cracked by the release heat. The amount of released gas was enormous.

Static test firing #2 (50g):

2011-08-25

RoverX



This is a lunar rover study I have done for the Google Lunar X Prize. RoverX is a so called wheg robot. I was inspired by the work of the Case Biorobotics Lab. I started with some sketchup drafts before I built the robot, using 2mm and 1.5mm aluminum sheet.

The wheel legs are from VEX. I've added 6mm wheel hubs to connect the wheels with the 4 gearde motors (cytron-12v-12rpm-166oz-in-spur-gearmotor).The motor driver is a Sabertooth 2x25, controlled by simplified serial.

Arm under construction:

The main board and the robot arm control board:

The PIC12F683 monitors the voltages of the two Li-Po batteries. If the voltages drop under a certain limit, a buzzer starts to sound:

Remote control, using cheap 433 MHz transmitter module:

RoverX with LADAR:

Some videos of the rover:









2011-08-24

Tardigrades in a cubesat

One of my ideas from the good old Google Lunar X Prize days: Study single-celled organisms by a microscope, implemented in a CubeSat and send live stream videos of the single-celled organisms back to Earth:


Later I wanted to use water bears (tardigrades), launched in try state and only then supplied with growth medium in low Earth orbit. The oxygen supply was planned to be done by a small oxygen container, a separate oxygen chamber with exchange membrane or unicellular algae in the growth medium by photosynthesis. Here is one of the first drafts of the 'space microscope':
And the prototype:

To find tardigrades in Shanghai was more difficult than we thought. Finally we found this lazy specimen :
video

See also NASA's O/OREOS nanosatellite. The satellite was successfully launched as a secondary payload on STP-S26 led by the Space Test Program of the United States Air Force on a Minotaur IV rocket from Kodiak Island, Alaska on November 19, 2010 - one year after I had published the idea in a Google Lunar X Prize blog.

2011-08-23

Cloud chamber for cosmic ray research

In 1948 war-built V2 rockets with nitrogen gas operated Wilson cloud chambers were used as a major tool in cosmic ray research:

From July 1948 edition of Popular Science

Reading this article, the idea was born to build a much smaller Wilson cloud chamber, operated by compressed  CO2, and launch it on a weather balloon or experimental rocket:

I built a first prototype. The PCB in the front is the HV source for electrostatic clearing field. The chamber is illuminated by a line laser. The alpha particle source is Am241.

This video shows the operation of the chamber:


I made 3-D-drawings with Google Sketchup and my friend Russell helped me to manufacture all the parts.
Unfortunately the choosen PMAA pipe cracked as soon as it got in contact with isopropyl alcohol (solvent crazing). The project is now on hold. I have to go on some day.

Simple Geiger counter to measure cosmic radiation by a rocket

The GM tube and the transformer modem are from Sparkfun. I have slightly modified the original schematic, taking the impulse from the cathode of the tube, not from the anode, and added a Schmitt trigger  and  a RC filter (R9/C4) to get a clear TTL output signal for counting the impulses with a micro controller.

Schematic (click to enlarge)

The Geiger tube has a mica window for alpha radiation.  I used americium-241 from a dismantled ionization smoke detector to test the Geiger counter. Americium-241 is a so called alpha emitter and has a half-life of 432 years. About one percent of the emitted radioactive energy of 241Am is gamma radiation.



Weight of the prototype, built on perfboard:


Hexaphenox - Epoxy composite propellant

To following illustration describes a procedure how epoxy can be used as a binder for hexaphenox:
Fresh formed hexaphenox/epoxy composite propellant:

Hexaphenox/epoxy composite propellant after the hardening process has started:

Newspaper rocket fuel

Have you read the newspaper today? What have you done with the newspaper? Thrown it in the dust bin or recylce bin? Can you imagine, newspaper can be rocket fuel and blast us to the moon or to other planets?
I had this idea, searching for a suitable binder and reinforcement of the grain for hexaphenox propellant. The binder and part of the fuel is polyvinyl acetate (white wood glue). The secondary fuel is old newspaper. The oxidizer ist KClO3. It is a kind of cellulose-reinforced plastic propellant. The video shows a test firing of 70g polyvinyl acetate/cellulose/KClO3 propellant:



 The propellant was made as following:
Some converted JPGs from the video (using Free Video to JPG Converter):
Propellant dries in the baking oven:
 Finished propellant grain:
 

Solid-steam rocket motor

I while ago (middle of May 2010) I came up with following idea:

The solid propellant heats up the alcohol or water during combustion reducing thermal loading of the nozzle and combustion chamber. Because the casing is double - walled and liquids are so difficult to compress, the combustion chamber pressure can remain very high. As pressure rises, a nozzle made from ductile material might start to deform in a manner so as to optimize the expansion depending on the altitude (aka altitude compensation). Once burnout of the solid propellant is completed, the rupture disc bursts or is burned away by the solid propellant, and super - heated steam flows through the nozzle and expands, which results in some additional thrust. Using water or alcohol preheated prior to launch can warm up the solid propellant and improve its combustion performance as well.

 I furthermore proposed a design, using copper fittings:
Rick Maschek from the SS2S team and his rocketry friends built a first prototype end of the year 2010, using hard soldered copper fittings and tubes:
A case bonded sugar/KNO3 propellant with cone shaped core was used for the static test firing. As they were afraid the motor would CATO, the nozzle was removed prior ignition:



Rick gave the motor a new name: SAM, an abbreviation for Steam Assisted Motor.

2011-08-22

Sugar Shot Weekly Activity Report: August 15-21, 2011‏

Paul Avery overcame the water leakage issues and reports that the Delay Plug has been successfully hydrostatic pressure tested to the specified 1330 psi (90 bar). This is a significant development that verifies the structural design of the Delay Plug (done by Carlos de los Santos). The result also confirms the quality of Paul's fabrication of the Delay Plug. Joel Farley also deserves a 'tip of the hat' for fabricating the high-quality mould.

Forward motor casing set up for hydrostatic testing of the Delay Plug. The hydraulic pump is also seen connected to the motor:
View of the Forward Bulkhead end of the setup:
 A cordless drill is used to power the hydraulic pump:
 
 Filling the chamber with water:
The pressure gauge indicating target pressure achieved (less a few psi leak-down):
(Photos courtesy Roger Paskell)

Paul subsequently hydro-proof tested the aft motor casing assembly to 1000 psi in order to verify its structural integrity and pressure tightness. As well, the Delay Grain was removed from the Midbulkhead and is ready to be re-cast to its full size.
Rick and Paul were at the FAR test site this past Saturday performing various tasks relating to the upcoming motor firing. The 12th and final propellant grain was cast at the site. The steel backing plate for the test stand was completed. An alternative deluge water supply system was worked out. Video showing 12th grain segment and a demonstration burning of hot propellant:


The static firing of the DSS BP motor is being tentatively scheduled for Saturday, September 10th.

Dassault Systèmes SolidWorks Corp. has generously agreed to sponsor Sugar Shot to Space by providing the following:
1. One (1) license of SolidWorks Premium software; and 
2. One (1) license of SolidWorks Simulation Premium software; and 
3. One (1) license of SolidWorks Flow Simulation software
This is an important development that will benefit the development of both DSS and ESS vehicles. In return for their sponsorship, SS2S will perform co-marketing activities such providing our 3D models to SW to create images and animations for use in marketing materials, assist DS SolidWorks in the preparation and final approval of press releases, and having members of SS2S appear at an upcoming SolidWorks World.
Conference (expenses paid by SW).  A huge thank-you goes out to Jacob Ferriera for making this happen.

DSS's primary sponsor, Markus Bindhammer, has generously donated a BoosterVision GearCam HD-DVR. for use with SS2S activities. Markus has tried out the camera in flight and is impressed with its performance. We will certainly put the camera to good use.

Sugar Shot to Space is on facebook. Check us out.

Help SS2S make it to Space. We need all the support we can muster.