Overview

The launch of Hermes 2 occurred at 11AM on July 6, 2019 from Friends of Amateur Rocketry in the Mojave Desert, CA. The launch operations were some of the smoothest in team history, due to great effort in rehearsals and procedures planning.

The Hermes 2 vehicle was 138.2 inches long and weighed 167.4 lbs at liftoff. For the second year in a row the FAR ignition system experienced difficulties on the first launch attempt. A quick recycle of the count and a hot-swap to FAR's wireless system yielded positive results and the motor lit successfully. A timeline of flight events is presented below. The onboard video is considered the timing master for all events.

The exact cause of the anomaly is unlikely to be conclusively determined, but we have several open fault trees which provide a path forward to resolve high-risk items prior to flying again.

Systems

Flight Performance

Altitude, velocity, acceleration, how they compare to expected values.

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• Fourier Transform of vehicle pitch and yaw rates

Comparison to pre-flight simulations

Projected Flight Performance

• Expected Apogee
• Expected burnout velocity and altitude

Propulsion

Flight Overview

May just be a link to the P9100 #2 page, but a dedicated write-up would be appreciated.

Ignition Transient

We lit the motor fast and hard this year. Good job laying the chuffing from Hermes Flight 1 to rest.

Nozzle Liberation

Estimate the centripetal acceleration that caused the nozzle to be ejected.

Estimate the time that the nozzle was liberated

Nozzle Erosion

Was the nozzle erosion we saw on this flight a factor of flight, stochasticity, or did it occur after the failure?

Recovery

Overview

Piston Actuation

Soft Goods

Why do we think we couldn't find them? When do we think they fell out of the rocket?

Avionics

Flight Overview

Away team - great

Telemetry - great

Cameras remote start - big improvement, ways to go

Lithium Polymer Battery Review

Can we get a table of all the batteries we flew and all of them that blew up here?

TeleMega GPS Lock

Discuss TeleMega GPS lock status, proposed resolutions here

Structures

Flight Overview

Fin Failure

Weather it was the impetus or symptom of the failure, Hermes 2 returned to the ground 4 fins short of a rocket.

Uncertain Fate of Nose Cone

Do we think it worked? Might it have buckled?

Paint

Should we consider better paint for next year?

LE Recovery Guard

Looks like it did an admirable job

Avionics Shield

Acrylic Bad

Payload

Flight Overview

Camera Arming Difficulties

Payload DAQ Fate Unknown

Noise on LE DAQ

Was this the p-tap? Systemic? From the board?

Operations

Flight Overview

Radio Comms

• Freaking awesome
• Ensure people know how to use them, especially people high up the chain of command
• Radio discipline, especially for the away team
• Have a 'CapCom' who narrates the launch for people not on the flight line

Transport

Gas in cars. 2 SUVs was good. Coffee shop purchases bad

Camping

How'd it go?

Recovery Operations

Running to the booster - bad, need to improve discipline after a failure

Search Line - went too far, need to plan search area before leaving

More people watching in other directions, temptation is too high just to stare down-range. We may have missed soft goods or nose cone coming down elsewhere on the range