Launch Site Survey and Planning

Planning a launch should involve specific review of safety requirements. This is not limited to HPR Launches. When you agree to conduct a launch in a school yard or sporting field, you are responsible for conducting the launch according to all applicable rules. A site survey can, for example, determine the maximum motor rating allowed to launch at a given site based on the maximum supported altitude of flight. This is dependent on the dimensions of the area, and on proximity to occupied structures and roadways.

I have had the experience of conducting Class 1 launches in several locations that were risk-averse to the point of involving the fire marshal's office in approval of the event. This is actually not a problem, as it is an opportunity to educate other professionals about rocketry. A good site survey with basic information overlaying a map image of the site will result in a bit of back and forth about the rules, likely recovery area of the rockets, and clearance to occupied structures and roadways. This makes an interesting presentation.

There are several online tools I recommend for the simplicity and fairly high accuracy of mapping. Both Google Maps and Google Earth are free and work in a browser tab. They include areal views suitable for an accurate understanding of the area. They also include measuring tools that are fairly easy to use.

As for determining the actual altitude you want to request, you have to decide how high you can fly rockets based on the limitations stated in 14 CFR 101.25 (g) as well as NFPA 1127 and the High Power Rocket Safety Code, which are now aligned. 14 CFR 101.25 (g) states that you must observe the greater of the following separation distances from any person or property that is not associated with the operations: Not less than one quarter the maximum expected altitude;

457 meters (1,500 ft.);

In other words, if you would like to request an altitude limit of 8,000 feet AGL on your application, then no person or property not associated with your launch operations can be located within one quarter (1/4) of that altitude, or 2,000 feet, from your range location. Conversely, if you measure the distance from the closest person or property not associated with your launch operations to be 3,000 feet, then the maximum altitude you can request would be 12,000 feet AGL.

Just remember that you must observe the greater of the two defined separation distances (i.e. the minimum distance from your range location to any person or property not associated with your launch operations is 1,500 feet). Requesting a 4,000 foot AGL maximum altitude does not mean your minimum separation distance is 1/4 of that. The minimum is always 1,500 feet. If the applying individual or organization would like to conduct nighttime rocketry operations at the same launch site, then another piece of information to include in Box 8 is a separate altitude range for those operations. The maximum altitude must still follow the limitations stated in 14 CFR 101.25 (g), but since nighttime operating altitudes approved are typically below those of daytime operations, no verification is really needed.

When determining a nighttime altitude, always keep in mind that the higher a rocket travels in the dark, even with the brightest illumination, it can be harder to track the entire flight profile and therefore become a serious safety concern to anyone on the ground.