1. Longhorn Rocketry Association
General Meeting No.3
09/22/2017

2. Certification Team First build tomorrow, 9/23, at 10 am in the LRC
Should take hours
PAY YOUR DUES PLZ

3. Movie Night 9/30/2017 7:15 Location to be confirmed

4. Current Events Last Week
“Space is important or something.” ‘Mad Dog’ Mattis
Current Events Last Week

5. Orbital ATK Acquired by Northrop Grumman

6. Orbital ATK Acquired by Northrop Grunman
7.8 Billion USD cash
Total value of the deal exceeds 9.2 billion (including debt assumption)
Follows Rockwell Collins acquisition by United Technologies

7. OSIRIS REx Gravity Assist

8. OSIRIS REx Gravity Assist
Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer
First US mission to return a sample from an asteroid
17,000 kilometers from the Earth’s surface during the pass at 11:53 AM Central
Will travel to Asteroid B Bennu

9. GRACE Retirement

10. GRACE Retirement Gravity Recovery and Climate Experiment
2 Spacecraft have been active since 2002
Decommissioning follows recent issues with GRACE-2 power supply issues
Replacement is GRACE-FO; launch delayed following :Russianpolitik:

11. SAC Work Days Finally getting the ball rolling Come learn things!
Today 6~8/9PM (FOOD TODAY – AIAA Cookout – 6:30 pm – Creekside Lawn)
Tomorrow 8AM~12:00N

12. Flight Systems - To Do List
Brand Spankin’
· Learn OpenRocket & RASAero (Free)
· Design a rocket to SAC 10k COTS requirements
· Read NAR Handbook
· Get laser cutter and CNC mill certified at the Maker Studio
· Learn SolidWorks
So-So
· Learn basics of ANSYS (Free)
· I’ll be releasing what I want you to simulate later in semester
· Attend a few AARG launches and talk to the veteran rocketeers
Big League Hot Shots
· Come talk to us!
A Few Notes/Suggestions
· Get to work now! (especially ASE128ers)
· We are not here to hold your hand. We are here to guide.
· What you put in is what you will get out
· In all seriousness, the interwebs is your best friend. There are tons of tutorials
· “Unless you try to do something beyond what you have already mastered, you will never grow.” -Ralph Emerson

13. Rocket Engine Power Cycles
Nicolas Diaz
LRA President & Program Manager, Propulsion Lead
09/22/2017

14. Solid Rocket Motors Pre-mixed fuel & oxidizer in solid grain form
NOT throttleable
Adjust thrust/time by changing grain geometry
Very simple (low Isp)
Ex: Cert Rockets, Fireworks, Missiles

15. Hybrid Rocket Motors/Engines
Solid fuel grain, liquid oxidizer (typically)
Adjust thrust/time by changing fuel grain geometry
(AND/OR) Adjust thrust/time by controlling ox mass flow rate to engine
Medium complexity (med Isp)
Ex: RocketMotorTwo, Taurus

16. Liquid Rocket Engines Liquid Oxidizer & Liquid Fuel Throttletable
High complexity (high Isp)
Ex: F1, SSME, etc..

17. Rocket Nozzles ↑𝐏 𝐜 ≈ ↑𝐕 𝐞 𝐹=𝑚𝑎 𝐹= 𝑚(𝑣 𝑒 − 𝑣 0 ) 𝑡
𝑎= 𝑣 𝑒 − 𝑣 0 𝑡
𝐹=𝑚𝑎
𝐹= 𝑚(𝑣 𝑒 − 𝑣 0 ) 𝑡 Vo Ve Fa FR
𝐹= 𝑚 𝑣 𝑒 + ( 𝑃 𝑒 − 𝑃 𝑎 ) 𝐴 𝑒
Pressure Thrust
↑𝐏 𝐜 ≈ ↑𝐕 𝐞

18. Rocket Engine Cycles Why do we need engine cycles?
To pressurize propellants
Minimize dry mass while increasing chamber pressure

19. Pressure Fed
Oxidizer
Fuel
High pressure gas (helium, nitrogen, etc) used to pressurize propellant tanks
Pros: Simple
Cons: Heavy Tanks (Tank Pressure > CC Pressure)
Pressurant
Scimitar Engine
*Over-simplified* =>
(Usually has regenerative cooling)

20. Gas Generator Engine Cycle
Turbine
Pump
Pump
Some fuel and some oxidizer tapped from main lines and combust in pre-burner. Pre burner then powers turbine which runs shaft to both pumps
Pros: Light Tanks, Simple(r than SC)
Cons: Open Cycle (GG exhaust lost)
Merlin 1D

21. Fuel-Rich Staged Combustion Engine Cycle
ALL fuel and some oxidizer combust in pre-burner, which runs turbine and single shaft which runs both pumps
Pros: Light Tanks, Closed Cycle (all propellant used)
Cons: Complex, Risky (turbine seal required to separate oxidizer-rich gas from the fuel turbopump or fuel-rich gas from the oxidizer turbopump)

22. Full-Flow Staged Combustion
High pressure gas (helium, nitrogen, etc) used to pressurize propellant tanks
Pros: Light Tanks, Closed Cycle (all propellant used), full gasification of both propellants
Cons: VERY Complex
Raptor Engine