Fuels for Space Flight

Handling Hypergolic_Fuel_for_MESSENGER spacecraftFuel for Thought.

by Robert Brand. Fools and Fuel. It is the one thing that you can’t avoid and possibly the biggest risk to spaceflight. Fuel.

ThunderStruck will start with the premise that we are going to use the safest fuels and the greenest where ever possible.

Since we are initially talking about booster capability, we are looking at solid fuels and for safety, we will also not use hypergolic fuels as they are very dangerous.

This excerpt from Wikipedia:
https://en.wikipedia.org/wiki/Hypergolic_propellant

A hypergolic propellant combination used in a rocket engine is one whose components spontaneously ignite when they come into contact with each other.

The two propellant components usually consist of a fuel and an oxidizer. Although commonly used hypergolic propellants are difficult to handle because of their extreme toxicity and/or corrosiveness, they can be stored as liquids at room temperature and hypergolic engines are easy to ignite reliably and repeatedly.

In contemporary usage, the terms “hypergol” or “hypergolic propellant” usually mean the most common such propellant combination, dinitrogen tetroxide plus hydrazine and/or its relatives monomethylhydrazine and unsymmetrical dimethylhydrazine

Our booster will have a mass of about 2500Kg to 3,000Kg with fuel and the fuel will be about 2/3rds of the mass.

Below is a list of most common space fuels in use today. Please look up any words that you don’t understand.

We will discuss the Specific Impulse and Density Impulse more in a later post.

Specific Impulse:

Wikipedia:    https://en.wikipedia.org/wiki/Specific_impulse

Specific impulse (usually abbreviated Isp) is a measure of the efficiency of rocket and jet engines. By definition, it is the total impulse (or change in momentum) delivered per unit of propellant consumed and is dimensionally equivalent to the generated thrust divided by the propellant flow rate. If mass (kilogram or slug) is used as the unit of propellant, then specific impulse has units of velocity. If weight (newton or pound) is used instead, then specific impulse has units of time (seconds). Multiplying flow rate by the standard gravity (g0) before dividing it into the thrust, converts specific impulse from the mass basis to the weight basis.

A propulsion system with a higher specific impulse uses the mass of the propellant more efficiently in creating forward thrust, and in the case of a rocket, less propellant needed for a given delta-v, per the Tsiolkovsky rocket equation. In rockets, this means the engine is more efficient at gaining altitude, distance, and velocity. This is because if an engine burns the propellant faster, the rocket has less mass for a longer period of time, which makes better use of the total force times time that was acquired from the propellant. This is much less of a consideration in jet engines that employ wings and outside air for combustion to carry payloads that are much heavier than the propellant.

Density Impulse:

https://www.quora.com/What-is-density-impulse-and-why-do-propellants-with-higher-densities-have-higher-density-impulses

Impulse density is a way of measuring the performance of different propellants regardless of their density. It’s a measure of how much force per time (impulse) you’ll get from a given volume of propellant. Higher density fuels have a higher Impulse Density because Impulse density is basically the propellants Specific Impulse multiplied by it’s density.

As comparison Lox-Butane and Lox-Methane both have a specific impulse of 365s, but the average density of Lox-Butane (at 1000psi) is 890.62kg/m3 while Lox-Methane is 823.34kg/m3. So Lox-Butane’s Impulse Density = 890.62 * 365 = 325076.3Kg-f-s/m3 and Lox-Methane = 300519.1Kg-f-s/m3.

This basically means that per Kg of Lox-Methane you’ll get the same Isp as Lox-Butane, but Lox-Butane can be stored in a smaller tank.

ROCKET PROPELLANT PERFORMANCE
Combustion chamber pressure, Pc = 68 atm (1000 PSI) … Nozzle exit pressure, Pe = 1 atm
Oxidizer Fuel Hypergolic Mixture Ratio Specific Impulse
(s, sea level)
Density Impulse
(kg-s/l, S.L.)
Liquid Oxygen Liquid Hydrogen No 5 381 124
Liquid Methane No 2.77 299 235
Ethanol + 25% water No 1.29 269 264
Kerosene No 2.29 289 294
Hydrazine No 0.74 303 321
MMH No 1.15 300 298
UDMH No 1.38 297 286
50-50 No 1.06 300 300
Liquid Fluorine Liquid Hydrogen Yes 6 400 155
Hydrazine Yes 1.82 338 432
FLOX-70 Kerosene Yes 3.8 320 385
Nitrogen Tetroxide Kerosene No 3.53 267 330
Hydrazine Yes 1.08 286 342
MMH Yes 1.73 280 325
UDMH Yes 2.1 277 316
50-50 Yes 1.59 280 326
Red-Fuming Nitric Acid (14% N2O4) Kerosene No 4.42 256 335
Hydrazine Yes 1.28 276 341
MMH Yes 2.13 269 328
UDMH Yes 2.6 266 321
50-50 Yes 1.94 270 329
Hydrogen Peroxide (85% concentration) Kerosene No 7.84 258 324
Hydrazine Yes 2.15 269 328
Nitrous Oxide HTPB (solid) No 6.48 248 290
Chlorine Pentafluoride Hydrazine Yes 2.12 297 439
Ammonium Perchlorate (solid) Aluminum + HTPB (a) No 2.12 277 474
Aluminum + PBAN (b) No 2.33 277 476

More discussion on fuels in a future post and we will explain our initial choice of booster propellant. The results of an explosion can ruin a flight or kill people. Safety is the big issue. More on that too in a later post.

aptopix india rocket fuel explosion

Calculating Maximum Speed in Free Fall

100km accelerationFree Fall Speeds

by Robert Brand and Todd Hampson

Oddly enough, there is very little information on the web for calculating the maximum speed that a craft will fall from a specific height. It is a complex calculation requiring knowledge of the shape of a craft, the size of the craft, the amount of gravitational attraction at each height, the thickness of the atmosphere and the mass of the vehicle.

Todd Hampson has done some great work in getting the information together although he has not found a simple formula for calculating atmospheric density. He has temprarily used look-up tables and that has caused some rather “jerky” graphs. He will work on embedding a formula into the equations and removing the problematic look-up tables. None the less, this is a story of our travels and thus our problems too. Eventually it will be our triumphs too, but a bumpy chart is not a major worry to me, especially as we already know the solution. Now for the fun stuff.

Calculations, Calculations and More Calculations

Getting something “just right” the first time is near impossible and this is no different. Lots of complex data and no simple formula for air density, simply because it is not linear and non anything else. Tomorrow we will add the formula into the data and smooth out the bumps.

Today let us look at the graph that is all important, but first let’s look at an version of ThunderStruck falling from 100km. We will need to do this for Phase 2 with a different craft, but let’s look at the maths.

Todd says:
– For mass of the vehicle I used 10kg.
– For the Area of the object in direction of motion (vertically downwards I am assuming for the high speed part of the fall) I calculated the cross sectional area of the cone ie: a circle using the diameter of 600mm as per the current drawings.
– For the Drag Co-efficinet there was a URL on the VUId page that pointed to an aerospace.org page discussing different drag co-coefficients. For a 3D cone the Cd is calculated using a formula that needs a half-vertex angle. From your drawings (cone depth 450mm, cone diameter 600mm) half-vertex angle is 33.7 degrees.

100km release; max speed

max speed for an aircraft released from 100km – from a sounding rocket apogee of 100km

In the graph above, the first part of the flight was a little more difficult than I thought as lots of things are changing as it falls ie: gravity, air density, drag etc but I’ve got there now.

The first model I have done is the 100km drop test. I need to clean up the data below 18000m but the show is well and truly over by then anyway, but I will get it right so the graph is correct (I need to be more accurate with the air density below 18km).

This says a lot. Thanks Todd. This shows that tourist flights to space at just over 100km altitude at apogee will reach a top speed of Mach 3 on their return – that is about 1,050m/s. Then without any further intervention, they will slow to a fall of about 50m/s near the ground. This shows that the Virgin Galactic trick of feathering the craft is all about stability and not speed. There is nothing that will prevent the craft from reaching this speed since there is not enough air to interfere with the acceleration. The “chunky” graph below shows that clearly. Please assume that the peaks to the left in the deceleration part of the graph are correct.

Acceleration from 100km fall and then deceleration

Acceleration from 100km fall and then deceleration

Free Fall Speeds

From the above, you can see the acceleration is flat and continuous until the craft reaches an altitude of 60km and the acceleration starts to slow. It crosses the zero point of a stable speed at about 47km and then begins to decelerate quite rapidly until it reaches 33km altitude. At this point the deceleration slows down and at 20km altitude the deceleration is slowing in the thick air. You may notice that the maximum deceleration is 38m/s/s and since we accelerate at nearly 10m/s/s when we jump from a platform, simply put every 10m/s/s equates (rule of thumb) to 1G. This means that any craft headed straight down will experience a maximum G force of about 4G. Nothing too harsh. Slowing from orbit is very different and we will eventually cover this in future posts about re-entry.

The first thing to notice is that we will never reach Mach 3 from a release at around 45km. We will achieve over Mach 1. There are a few things that we will need to play with to reach the desired Mach 1.5 and we will cover that in a future post as we look at the graph for a drop from 45km and another from 35km.

ThunderStruck Models Set the Scene

1/15 model from 3D Printer using Grey Stock

1/15 model from 3D Printer using Grey Stock

ThunderStruck Models Make it Clear to Everyone

by Robert Brand

This is the week the world’s press get to actually see what the Phase One test vehicle will look like. we now have 2 models nearing completion – just waiting for the paint to dry. We have a a 1/15 model and 1/6 model. The 1/15 model is printed directly from a printer in 3 parts. The 1/6 model is made from a 100mm diameter sewage pipe and wooden wings. They are not the right thickness and they are not razor sharp, but it will allow TV cameras to get up close and personal.

Bruce Boler and Jason Brand with ThunderStruck Phase One 1/6 Model

Bruce Boler and Jason Brand with ThunderStruck Phase One 1/6 Model

Unfortunately the paint is still drying and we cannot get the detail on the outside, so it will be pure white for the moment. The image to the left shows Bruce Boler and Jason Brand with the 1/6 model under construction. Bruce is the engineering genius and his model is immaculate and very strong. Now we have something to show the media when they arrive and one TV station arrives tomorrow so we are meeting the deadline.

It has been a real team effort. I have drawn the plans, Ben Hockley has printed the Nose Cone and Bruce has put it together. As I type this, the finished model is drying the last coat of paint on Bruce’s work bench.

Bruce Boler Spray Painting the Phase One model

Bruce Boler Spray Painting the Phase One model

At this time, we only have a white top coat and no trim, but it is a thing of beauty. We will not have time to add any trim before the major TV interview tomorrow at 4pm. The interview will take time to assemble and so it may not make it to air for a week or so and also they are making an animation video of he flight path. We are hoping that all of this will inspire others to either get involved or get behind what we are doing.

20150224_164828

That is me on the left. I really wanted to pick the model up, but it was covered in wet paint. The only question left for us and it is a major one: What colour should we make the aircraft. White is not a great colour if you want to see it in the skies with the naked eye, but it looks great with the right tri20150224_164901m colours and it does not conflict with any logos, names and other stick-ons.

That is Jason on the right with a wide grin. For him this is really coming together with a rush this week. Jason is still in his school uniform. A concept that will be strange to many countries. It was sports afternoon and Jason does rock climbing, so shorts and a tee-shirt. It is summer here in Sydney.

Phase One Thunderstruck 1/6 nosecone

Phase One Thunderstruck 1/6 nosecone

The nose cone on the left is the new design. A little longer and a little curved on the transition to the fuselage. I have not put the full set of measurements in the diagram, but Ben turned it into a thing of beauty with his 3D printer and it now sits on top of the large model.

Prototypes will mean change, but it will be only minor changes from this basic design. The craft will have a camera in the nosecone for the forward view for the remote control pilot. We will also add a camera into the rudder area on one side so that we can get a better view in flight of the craft. Jason will control the camera switching from his remote control unit. The new image will still be overlaid with the On Screen Display of the flight instruments. Below is the model drying for its first display on National TV tomorrow.

ThunderStruck Phase One 1/6 model

ThunderStruck Phase One 1/6 model

Apollo 11 Interview in Full

Robert Brand at a recent London Space Conference

Robert Brand at a recent London Space Conference

Apollo 11 Interview – Spaceflight Magazine

by Robert Brand

As you all know, I am heavily involved in the space sector and you may have already read that I was Interviewed in Spaceflight magazine. First, let met say again that I did NOT put the title on the page “Saving Apollo 11” Nor did I say anything so over the top. It seems the editor thought that a nice touch. It was in UK Spaceflight magazine and headlines sell magazines.

You can read the entire Apollo 11 story on-line on the link below.

My words are very tame in the interview in that regard. My friend Nick Howes from the UK also thinks I am being humble when I tell him I didn’t do much other than standard wiring. It was in the NASA Apollo 11 Sydney switching centre for the mission – switching the Honeysuckle Creek feed and the Parkes feed. As I said. editors want to sell magazines. They embellish the facts where there is an opening.

This piece was the lead story of 3 more Apollo stories – the next 3 issues will each have an interview by Nick Howes. Two of them are with astronauts Rusty Schweickart and Jack R. Lousma and the last one is with Sy Liebergot, the Comms guy for mission control during the Apollo 13 crisis. I am pleased that they thought my story was interesting enough to include it in the Apollo series. Other than the title, the interview is very accurate from my perspective.

Spaceflight-Cover-2014-12(Widget)Read the Full Story by clicking below.

http://www.bis-space.com/2014/11/06/13775/saving-apollo-11

 

Press Release 1

Jason recovering Payload Cameras gets his photo snapped

Jason recovering Payload Cameras gets his photo snapped. Robert Brand top right

Press Release 1 – 12 year old to Break the Sound Barrier

Thursday 9th Oct 2014

Release Date: IMMEDIATE

12 year old to Break the Sound Barrier

Sydney, NSW, Australia.

Jason Brand, 12 years old has commenced work on building a Remote Control Glider expected to reach Mach 1.5. He has worked with his father, well-known Space Entrepreneur, Robert Brand, on High Altitude Balloon launches since he was 9 years old. Coupled with his love of flying remote-controlled aircraft, Project ThunderStruck was born. Jason will use a massive high altitude balloon to take his glider to over 40km altitude (>25 miles) often called “the edge of space” and release it. The glider will dive through the extremely thin atmosphere and into the record books. It will be controlled from the ground via video and radio links and reach an expected top speed of around Mach 1.5 (1,800kph or 1,120mph).

Jason thought of the idea when his father was talking about a winged re-entry vehicle project that he has commenced. He was discussing the testing required at different stages of the flight and Jason realised that he could actually fly the tests for the transonic phase – the area around the breaking of the sound barrier.

Jason has been immersed in flying for many years. Since he and his father launched their first balloon when he was 9 years old. He was so inspired that he studied and passed his test to become a radio amateur operator (HAM) on his first attempt, again at age 9. 19 balloon launches later, they have maintained an unheard of 100% success in recovering their payloads. Jason flies radio controlled model aircraft, is a cadet in the Australian Air League (Riverwood Squadron) and is determined to solo at age 15. He has also be designing radio systems for long distance control and video. He will “see” from the cockpit camera via a video link and the instrumentation will be overlaid on the video. He will wear goggles and guide the aircraft through the dive, the leveling off at about 80,000 feet (24km / 15 miles) altitude. He will then fly the craft in for a landing.

Special tracking and GPS equipment will be required to verify the speed of the craft for the record books. Most GPS does not work above 60,000 ft and only special GPS systems will work near or above the speed of sound, like those used in missiles. Similarly the aircraft will carry a radar transponder that will advise other aircraft of the ThunderStruck aircraft diving at Mach 1.5. Even military aircraft do not get much over 80,000 ft and controlled airspace is below 60,000 ft. This will probably be the highest balloon and definitely the highest aircraft in the world that day.

This has never been done before and let alone by a 12 year old. It showcases STEM education (Science, Technology, Engineering and Maths) and the fabulous things that happen students are brought up to understand that most limits are there to be broken. Our motto is “New Heights and Breaking Barriers” and those include the Sound Barrier (1,233kph / 766 mph). Soon we will start our funding campaign as it will cost nearly $100,000 to make this a reality and we are looking for global support for such a spectacular event. On the day the event will be captured by cameras on the balloon, the aircraft and from the ground. These will be both live and also recorded. A live broadcast will be available on the Internet for the event scheduled for April 2015.

Website: http://projectthunderstruck.org

————————-

Contact:   Robert Brand – homepc@rbrand.com   Australia:  02 9789 2773    Int’l: +61 2 9789 2773

Photos of Jason and Robert Brand on the Project ThunderStruck webpage are available for publication as is the logo and the CAD images of the aircraft.  http://projectthunderstruck.org/media/

Jason Brand (12 y/o), creator, designer, builder and flier of ThunderStruck

  • HAM radio operator since he was 9 years old
  • First balloon launch and recovery at 9 years old
  • Member of the Australian Air League – Hornets Squadron, Riverwood, Sydney – Cadet
  • Flying Radio Controlled aircraft since 2013
  • Launched, tracked and recovered 19 High Altitude balloons and recovered 100% (all 19)
  • Attends Sydney Secondary College, Balmain Campus – Y7 in 2014
  • Is the Student Representative for Team Stellar – a Google Lunar X-Prize team headed for the moon.

 

Robert Brand: Leading Australian space entrepreneur, Senior Adviser for Team Stellar, ex-OTC staff member, amateur radio operator, Public Speaker on Innovation, Social Media and Space with a focus on Australian Space. Proud father of three amazing kids.

Worked on Apollo 11 equipment at 17 years old, supported Apollo missions, Voyager missions, Shuttle missions and ESA’s Giotto mission to Halleys Comet. Several times he was stationed at the Parkes Radio Telescope.

With his son Jason he has launched 19 high altitude balloon mission and recovered all 19 – two of them were in Croatia. He has designed a mechanism to turn a weather balloon into a zero pressure balloon during flight. Many of the balloon flight have been commercial flights for customers.

End Press Release.