Class 3 Amateur Rockets

The FAA (Federal Aviation Administration) has updated in December 2008 the regulations for amateur rockets [PDF], dividing them in three classes according to the complexity of the vehicles. In order to operate a rocket of class 3, it is required to request a certificate of waiver or authorization.

Astos Solutions provides several levels of support in order to accomplish with the FAA regulations.

1. Computation of aerodynamics^*
2. Nominal trajectory^*
3. Nominal and not nominal trajectory^*
4. ASTOS Amateur Rocket Edition software^* (request a trial in the "Your Astos" section)

1. Aerodynamics

Based on the dimensions and configuration of the vehicle we can provide an accurate estimation (software tool) of the aerodynamic force and moment coefficients, reference area, reference length and center of pressure position.

2. Nominal trajectory

Astos Solutions provides the information needed for the application, the codes between brackets (e.g. a5) refers to the FAA regulation points [PDF] in paragraph 101.29 (a-b) at page 73782:

• Highest altitude reached (a5)
• Maximum possible range (b2)
• Dynamic stability characteristics for the entire flight profile (b3)
• Planned flight profile (b6)
• Nominal impact areas, including those for any spent motors and other discarded hardware, within three standard deviations of the mean impact point (b7)

See here an output example.

Included in this package the customer will receive the ASTOS test case used to simulate the trajectory as well as three month license of ASTOS in order to check the model and perform some modifications.

3. Nominal and not nominal trajectory

Nominal information as detailed above plus

• Not nominal impact points (within three standard deviations of the mean impact point) due to no stage separation and no parachute deployment
• Not nominal impact points (within three standard deviations of the mean impact point) due to no stage separation and stage 1 parachute deployment
• Not nominal impact points (within three standard deviations of the mean impact point) due to no stage separation and stage 2 parachute deployment

See here an output example.

Included in this package the customer will receive the ASTOS test case used to simulate the trajectory as well as three month license of ASTOS in order to check the model and perform some modifications.

4. Permanent ASTOS Amateur Rocket Edition license

The customer has the possibility to buy a permanent license of ASTOS Amateur Rocket Edition with the following limitations:

• Based on ASTOS 7 with reduced set of models
• No optimization feature
• Only sub-orbital flights
• No commercial activity (just educational and amateur)
• No training (only 20 hours mail/telephone support)

ASTOS has been designed to simulate and optimize various aerospace missions, see ASTOS for more details. An extended knowledge of aerospace trajectory simulation is expected by the user; that is the reason why the purchase of an ASTOS license (without a proper preparation) could not guaranty the success in the simulation of the rocket flight.
ASTOS Amateur Rocket Edition is a simplified ASTOS version with a reduced set of models in order to facilitate the use for amateur rocket simulation. A complete example is provided as starting point for the modelling of the vehicle. The support hours provided can be used to request a customized template based on the user input: this could provide the customer the required starting point to perform his own simulation.

Required Inputs

In order to compute the nominal and not nominal trajectory (see points 2. 3.), the customer has to provide us a list of inputs that define the characteristics of the vehicle. Here after the most typical data are listed:

• Specific atmosphere profiles (air density, air pressure and speed of sound versus altitude), in case these are not available a generic model can be used (US Standard 76 or MSIS).
• Specific wind profiles (wind speed and wind direction versus altitude).
• For each engine, thrust profile versus time and propellant specific impulse (Isp); in case Isp is not available mass profile versus time.
• For each component, inert mass, propellant mass.
• For each configuration (e.g. at liftoff, after booster separation, etc.)
  • Aerodynamics, in case not available we can compute them (see point 1.)
    • reference area
    • reference length
    • aerodynamic force coefficients: drag/axial and lift/normal
    • aerodynamic moment coefficients: pitch, yaw and roll
    • center of pressure position
    • fin deflections
  • Moments of inertia and center of gravity position versus time, in case not available a simple approximation will be computed by us.
• Launchpad coordinates (altitude above mean see level, latitude, longitude).
• Launch rail length, elevation and azimuth.
• Time line of events (stage separations, stage ignitions)
• Parachute areas (main and drogue) and opening triggers (altitude, time, speed, others).

Validation

The Student Mavericks Rocket Project, sponsored by Sony, resulted in a successful launch on July 23rd of the two-stage Beagle IV from Black Rock, Nevada. On www.hobbyspace.com it was reported the following: "...According to the GPS data available, a projected trajectory for apogee was over 147000 ft MSL..."

This is perfectly in line with the prediction computed with ASTOS (see figure below where the without wind simulation is shown in red and the simulation with typical Black rock wind is shown in blue). The close-up shows the max apogee altitudes: without wind at 149,000 ft and with typical wind at 146,000 ft.

Please contact us at service@astos.de in case of questions or for a specific quotation.