Talos

Talos (ARES-1)
Launch 1 - L1
Launch date	February 6, 2016
Launch site	LUNAR
Launch 2 - L2
Launch date	Pending
Launch site	Pending
Launch 3 - L3
Launch date	Pending
Launch site	Pending
Project Daedalus Pegasus→

Team Summary

Stanford SSI Rockets Team - Talos,
Leland Stanford Junior University
Stanford, CA
Ian Gomez
Project Manager
iangomez@stanford.edu
Saylor Brisson
Team Lead
sbrisson@stanford.edu
Cameron Ramos
Avionics Specialist and Payload Supplier
calramos@stanford.edu
Lance Plater
lplater@stanford.edu
Jim Best-Devereux
jimbestd@stanford.edu
Moiead Charawi
mcharawi@stanford.edu
Ben Goldstein
beng2019@stanford.edu

Launch Vehicle Summary

The Talos rocket will serve as a test-bed for a new avionics system, Kythera. It will be flown under the legal ownership and operation of Cameron Ramos. Under the guidance of SSI, Talos will be responsible for the design and fabrication to be conducted primarily on the Stanford University campus, and testing, to be conducted off campus.

Payload Summary

The Kythera payload included within the rocket is a modular “plug-and-play” system to be used in all future Stanford SSI rocket launches. The system included in this launch will be its first generation and test. The Talos team is not responsible for the development and creation of Kythera, but is responsible for its integration into the rocket. The SSI Avionics Team will provide the final version of Kythera flown in the Talos Rocket.

Changes Made Since PDR

Motor Retention System

Our previous motor retention system was too heavy and complicated. We choose to simplify the design while reducing the weight by creating a new version. The first CAD prototype consissted of three aluminum bulkheads (informally named “sombreros” because of their odd shape) which were connected by four threaded rods. The bottom sombrero held in the rocket to prevent it from falling due to the gravitational forces, while the top sombrero prevented the motor from shooting through the rocket. Connecting the sombreros by threaded 1/4 20 rods would have spread out the load between the sombreros, but the system was already too heavy. Furthermore, a second set of three threaded rods was needed between the bottom sombrero and middle sombrero, since having three long rods instead of six short rods would be more likely to bend. Yet, these rods, along with the sombreros, added up to 11 lbs of weight (including the rocket motor casing).

Our new retention system is simpler, less weight, and also contains more features that the first CAD prototype was missing. The motor can now be removed more easily my simplifying the construction of the bottom sombrero. Furthermore, the fins are integrated with the retention system, which serves as a secure hard point for attaching the fin tangs.

Vehicle Criteria

Mission Statement

The Talos Rocket team is seeking to develop, build, and launch a rocket that fits the constraints imposed by Tripoli, so that one member of the Talos team receives L3 certification, while all members gain relevant rocket-building experience. We also seek to test a newly developed avionics suite, Kythera, for use on future projects.

Mission Success Criteria

The mission will be considered successful if one member receives L3 certification for launch of the Talos rocket, the avionics suite performs as expected, and all members gain valuable experience.

Constraints

1. Tripoli height ceiling of 16,800ft
2. Motor impulse must be greater than 5,120 Ns
3. Motor impulse must be less than 10,240 Ns according to California Law
4. Redundant avionics, wiring, and safe arm systems
5. Vertical descent speed of 20ft/s maximum upon landing
6. Budget of $4000.

System Overview

1. Payload
   

5.5” diameter by 6” high avionics bay, weighing  6 lbs.

1. Recovery
   

Dual deployment system of drogue chute and main chute.

1. Propulsion
   

Cesaroni Pro 75 6251M1400-P motor with a total impulse of 6251 Ns

1. Structures
2. Thermal Insulation
3. Telemetry and Tracking

Propulsion System

The propulsion system consists of propellant grains held within a Cesaroni motor casing, held in place within the airframe by means of a motor retention system.

Motor Details and Performance

The rocket’s propulsion will be provided by the Cesaroni Pro 75 M1400-P. This is an M-class motor with an impulse of 6,251 Ns and burn time of 4.47 seconds. To choose a motor, we considered several factors - to what altitude it would propel our rocket, Tripoli constraints, and California law. Tripoli requires a minimum of 5,120 Ns to receive L3 certification while California law restricts the use of motors with impulse above 10,240 Ns. Tripoli also constrains maximum height of L3 rockets to 16,800 ft, but all Daedalus teams were suggested to aim to go no higher than 10,000 ft. With our current projected mass of 37 pounds (which will most likely increase), OpenRocket simulations show our rocket meeting this height requirement.

The following graph shows the thrust of the motor(lb) vs. time(s).

Motor Casing

The motor casing is intended to hold the propellant load inside its treated aluminum casing. Since treated aluminum cannot be welded, we have modified our method of fastening the motor. Additionally, in order to make a safer propulsion system, we will not be screwing any holes inside the motor casing, as this would reduce the structural integrity of the motor casing. A higher chance of structural failure within the propulsion system would increase the chance of “KATO” (Catastrophe at takeoff).

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Motor Retention System

Initially, the sombrero design consisted of three motor ring retainers attached by four threaded rods. The entire subassembly encased the motor. However, as previously discussed above this sub-assembly was very heavy and lacked several features which were critical to the function for the rocket.

Flight Characteristics

Our rocket reaches an apogee of 9,600 feet 23 seconds after launch. Its maximum velocity is 973 ft/s (0.86 mach) and maximum acceleration is 402 ft/s<math>^{2}.</math> The drogue chute deploys at apogee and the main chute deploys at 300 feet to slow the rocket to a speed of 15 ft/s.

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File:Flight profile.png

caption Flight Profile from OpenRocket

Structural System

Materials

Our rocket will be composed of a variety of materials. Our airframe will be fiberglass-wrapped phenolic. Phenolic is a a relatively strong material in itself, but has the ability to be reinforced with other, stronger materials such as carbon fiber and fiberglass. A fiberglass phenolic body tube is the high power rocket supplies manufacturer Public Missile’s recommended choice to withstand forces on high power rockets exceeding 0.85 mach. Carbon fiber was considered, but safety concerns involved with working with the material as well as higher price points made fiberglass the preferred choice. The fins will be made of fiberglass, rather than aluminum or another type of metal to comply with ITAR restrictions.

Nosecone

We will employ a 6 inch diameter fiberglass nosecone manufactured by Public Missiles Ltd (PML), chosen to be compatible with the airframe. With a 4.2:1 diameter to length ratio, the nosecone will have an exposed length of 29 inches and will make up the top portion of the rocket. Both the drogue chute and main parachute will be contained within the nose cone, attached via Kevlar shock cords. The nose cone will be friction fit into the airframe, so that pressurization from the parachute deployment system can separate it from the airframe and release the parachutes. Check recovery section for more detail.

Fins

Three fiberglass fins will be located at the aft of our airframe. Their shape will be clipped delta (a right triangle with one point clipped off to create a trapezoid), a common fin shape for hobby rocketry that minimizes drag and maximizes stability. Each fin has a span of 6.5“, sweep of 9.625”, tip chord (T.C. in diagram) of 2.625“, and root chord of 13.5”. Additionally, the fins will The bottom of the fins will be 0.5" from the bottom of the airframe to account for the thickness of the bottom centering ring of the motor retention system.

File:Fin1.png

caption Fin

Airframe

A single airframe with an inner diameter of 6.007 inches, in order to accommodate the 6-inch diameter Kythera payload, will be used as the main body of the rocket. The manufacturer is Public Missiles, virtually the only online seller of 6-inch body tubes of this material. Both the airframe and nosecone are manufactured by Public Missiles to ensure a compatible fit. The airframe is 48 inches in height, sufficient length to hold the motor and payload. It has a thickness of 0.102 inches, an outer diameter of 6.109 inches, and will weigh 52 ounces.

Avionics and Telemetry

Avionics Teensy Pinout

File:Kythera Systems Architecture.pdf

caption Kythera Systems Architecture

Storage

The recovery avionics will be housed in a 3d printed chamber with two small holes to allow wiring to travel to each igniter and to equalize pressure with surroundings. A hole in the shoulder of the nosecone above the bulkhead will give the nosecone volume the same pressure as outside the rocket.

Main Recovery System

Our main recovery system (an alTOMiter) will consist of a custom avionics board made by the SSI Avionics Team which will a barometer and altimeter to determine the moment at which the rocket reaches apogee. At this point an electronic pulse will be sent to the first igniter, which will light the pyrodex contained in the charge well located on the aft side of the bulk head separating the main chute and drogue chute. The pressure created will push the friction fit nose cone from the airframe and release the drogue chute. Then, when the avionics detect an altitude of 300 feet, they will send a second charge to an igniter at the pyrodex-filled charge well located at the tip of the nose cone. This will create pressure to push the main chute against the bulkhead and release it from the rocket.

Backup Recovery System

The backup recovery system will be a stock RAVEN flight computer that is programmed to send a charge to the igniter 1-2 seconds after the main recovery should have sent its signal.

Mission Performance Predictions

Flight Profile

Manufacturing and Assembly

Motor Retainer

Each sombrero of the motor container is composed mainly of 2 stacked rings that have an inner diameter that matches that of the motor casing and an outer diameter matching that of the airframe that will be fabricated in the PRL. This insures that it fits tightly both around the motor retainer and inside the airframe. The motor retainer is attached to the airframe by screws and is secured in place by threaded rods that connect each sombrero to the ones directly above and below it to insure stability.

Bulkheads

Our bulkheads will use various materials in accordance with their purpose. Most of our bulkheads will be 3D printed and attached to the airframe with epoxy. However, due to our unique recorvery system, a bulkhead is required in the nose to prevent the main parachute from being deployed at the same time as the drogue parachute. This bulkhead will be made of plywood to insure that it breaks when the main parachute is deplyed and attached with epoxy.

Fins

We will be ordering our fins from Public Missiles. They are made of fiberglass and will be attached using the tang that Public Missiles will cut for us. We will cut a groove into the main rocket body that the tang will slide into. After inserting the tang into the groove, the fin will be secured with epoxy running along the sides of the tang.

3D Printed Materials

We will be 3D printing the housings for both avionics packages. The nosecone avionics housing will contain a hole to allow the barometer to accurately measure the air pressure to determine altitude. The housing will be strong enough to protect the avionics from the blast that seperates the nosecone from the airframe.

Kythera’s housing will be mounted inside the airframe and will also allow access to the ambient pressure to ensure that Kythera makes accurate readings. The housing will also be help brace Kythera for impact.

The hardpoints we will use to attach our shock cords to both the nosecone and airframe will be 3D printed as well.

Systems Integration and Testing

Major Vehicle Milestone Schedule

January 16: L1 rocket Launch
This launch will be used to gain experience with the mechanical components of rockets. No avionics will be added to this rocket.
Feb 20th: L2 rocket launch
This will serve small scale test on avionics system using L1 rocket as test bay. A bulkhead created by the avionics team will be placed inside the L2 rocket to test the new flight computer.
March 19th: L3 Rocket Launch
For the L3 launch, the results of the two previous launches will be taken into consideration. The bugs, difficulties...etc encountered during the L2 and L1 launches will isolated and overcome before the L3 launch. All of the prior knowledge will be integrated into this final launch.

Risk Management

The launch of a Level 3 rocket requires compliance of the NAR High Power Rocket Safety Code:

1. Certification. I will only fly high power rockets or possess high power rocket motors that are within the scope of my user certification and required licensing.

2. Materials. I will use only lightweight materials such as paper, wood, rubber, plastic, fiberglass, or when necessary ductile metal, for the construction of my rocket.

3. Motors. I will use only certified, commercially made rocket motors, and will not tamper with these motors or use them for any purposes except those recommended by the manufacturer. I will not allow smoking, open flames, nor heat sources within 25 feet of these motors.

4. Ignition System. I will launch my rockets with an electrical launch system, and with electrical motor igniters that are installed in the motor only after my rocket is at the launch pad or in a designated prepping area. My launch system will have a safety interlock that is in series with the launch switch that is not installed until my rocket is ready for launch, and will use a launch switch that returns to the “off” position when released. The function of onboard energetics and firing circuits will be inhibited except when my rocket is in the launching position.

5. Misfires. If my rocket does not launch when I press the button of my electrical launch system, I will remove the launcher’s safety interlock or disconnect its battery, and will wait 60 seconds after the last launch attempt before allowing anyone to approach the rocket.

6. Launch Safety. I will use a 5-second countdown before launch. I will ensure that a means is available to warn participants and spectators in the event of a problem. I will ensure that no person is closer to the launch pad than allowed by the accompanying Minimum Distance Table. When arming onboard energetics and firing circuits I will ensure that no person is at the pad except safety personnel and those required for arming and disarming operations. I will check the stability of my rocket before flight and will not fly it if it cannot be determined to be stable. When conducting a simultaneous launch of more than one high power rocket I will observe the additional requirements of NFPA 1127.

7. Launcher. I will launch my rocket from a stable device that provides rigid guidance until the rocket has attained a speed that ensures a stable flight, and that is pointed to within 20 degrees of vertical. If the wind speed exceeds 5 miles per hour I will use a launcher length that permits the rocket to attain a safe velocity before separation from the launcher. I will use a blast deflector to prevent the motor’s exhaust from hitting the ground. I will ensure that dry grass is cleared around each launch pad in accordance with the accompanying Minimum Distance table, and will increase this distance by a factor of 1.5 and clear that area of all combustible material if the rocket motor being launched uses titanium sponge in the propellant.

   image

8. Size. My rocket will not contain any combination of motors that total more than 40,960 N-sec (9208 pound-seconds) of total impulse. My rocket will not weigh more at liftoff than one-third of the certified average thrust of the high power rocket motor(s) intended to be ignited at launch.

9. Flight Safety. I will not launch my rocket at targets, into clouds, near airplanes, nor on trajectories that take it directly over the heads of spectators or beyond the boundaries of the launch site, and will not put any flammable or explosive payload in my rocket. I will not launch my rockets if wind speeds exceed 20 miles per hour. I will comply with Federal Aviation Administration airspace regulations when flying, and will ensure that my rocket will not exceed any applicable altitude limit in effect at that launch site.

10. Launch Site. I will launch my rocket outdoors, in an open area where trees, power lines, occupied buildings, and persons not involved in the launch do not present a hazard, and that is at least as large on its smallest dimension as one-half of the maximum altitude to which rockets are allowed to be flown at that site or 1500 feet, whichever is greater, or 1000 feet for rockets with a combined total impulse of less than 160 N-sec, a total liftoff weight of less than 1500 grams, and a maximum expected altitude of less than 610 meters (2000 feet).

11. Launcher Location. My launcher will be 1500 feet from any occupied building or from any public highway on which traffic flow exceeds 10 vehicles per hour, not including traffic flow related to the launch. It will also be no closer than the appropriate Minimum Personnel Distance from the accompanying table from any boundary of the launch site.

12. Recovery System. I will use a recovery system such as a parachute in my rocket so that all parts of my rocket return safely and undamaged and can be flown again, and I will use only flame-resistant or fireproof recovery system wadding in my rocket.

13. Recovery Safety. I will not attempt to recover my rocket from power lines, tall trees, or other dangerous places, fly it under conditions where it is likely to recover in spectator areas or outside the launch site, nor attempt to catch it as it approaches the ground.

Safety Hazards

Safety hazards will be handled with the utmost importance for the safety of the team, other individuals in the area and the rocket/payload. During construction extra care will be given to all activities that have the potential for harm. For the launch, the NAR safety code launch protocols have been laid out to determine if we are “No Go” for a launch or not. These protocols will be followed by all members of the team.

System Functionality

To decrease the chance of a critical system failure several systems will run with redundancies built in. Hardware will have backup systems in place in the event of a failure on the part of one of the components. An example of this idea in practice is the inclusion of two sensors for altitude that will be driving the recovery system. In order to be completely confident a failure will not occur we have designed around the inclusion of a backup to drive the recovery system in the event our first altimeter fails.

Activity Plan

Timeline

As Talos is a project under Daedalus, all Daedalus deadlines apply to Talos.

1. December, 2015
   1. 5<math>^{th}</math>: Daedalus PDRs due
2. January, 2016
   1. 21<math>^{st}</math>: Talos PDR
3. February, 2016
   1. 3<math>^{rd}</math>: Revised PDR
   2. 13<math>^{th}</math>: Hardware due
   3. 20<math>^{th}</math>: Certification Launch
4. March, 2016
   1. 5<math>^{th}</math>: Daedalus L3 CDRs due
   2. 12<math>^{th}</math>: Daedalus L3 hardware due
   3. 19<math>^{th}</math>: Daedalus L3 Rocket Launch

File:Talos Timeline.pdf

caption Timeline