Hello everyone,
Work on our remote rocket engine igniter has been quite slow as we've all focused on studying for our finals. As such, our project manager, Dalton Moffitt, has written up a post about how our designs for the project came to be. I've attached PDFs of the designs below.
We'll be resuming work as the summer session of our university come into full swing in a few weeks, so look out for us then!
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Hello again! Sorry for the delay in posts, but things became rather hectic for the build team over
the last few weeks and a mix of exams, final projects, and sickness brought progress to a screeching halt.
As finals wrap up here, building will continue once more but in the meantime I thought I would share a
little more about the project.
The need for the launch box arose when we began to consider launch sites for some our larger
planned rockets. Normally the primary location that high altitude launches can be conducted from is in
Black Rock Desert, Nevada. While there are some events there that provide facilities for a launch, it is
not always guaranteed that the event schedule would properly line up with our launch schedule. Thus
arose the need to develop a safe way to launch rockets.
In the design of our launch box, we began by reading up on the National Association of Rocketry
(NAR) guidelines. NAR’s purpose is to help foster and direct the amateur high powered rocketry groups
and as part of this has laid out extensive guidelines on the safe design and construction of a launcher
device. After going through guidelines, we began to consider the capabilities that we would like our
device to have: the ability to launch multiple rockets per day, a method to ensure that the rocket motor
is properly hooked up, the ability to launch different size motors, a double safety, and finally a method
to alert any bystanders unaware of the launch and warm them to step back to avoid any potential for
singed eyebrows. Finally, we conducted research on other designs for launch controllers that assisted us
in formulating our final design.
The final design consists of two separate components that work together to ensure a safe and
successful launch. I will go through both components as well as the features they contain and how they
work together in the next few paragraphs.
The first component, the launcher, consists of the main power supply as well as well as the
actual launch circuit which will supply a high current to an ignitor placed in the motor which will ignite it.
The launch circuit will feature several different power levels that allow for the ignition of various motor
sizes. In addition, the launcher contains a circuit that is capable of trickling a small amount of current
through the launch circuit. This allows us to determine if we have a proper connection and helps ensure
that the rocket launches the first time, every time. If the motor is properly hooked up, then it will
complete this circuit which also consists of a led and buzzer that will activate if we a proper connection.
Finally, the launcher also contains a siren that will activate when all safeties are removed, alerting
everyone around that a launch attempt is imminent. This is especially important at events where
multiple groups are working in the same area and can sometimes be caught unaware of other group’s
activities.
The second component is the controller. This device, as it name it indicates, allows us to control
the launch process. Besides featuring a main power switch that activates it, it also features dual safeties
and the actual launch button. The safeties are keyed switches whose keys are given to the lead safety
officers in charge of the launch. If the keys are not inserted and turned, the controller will not be armed
and will be unable to accidentally initiate a launch. When the safeties are deactivated, an LED will light
up on the controller to alert the operator that the safety was successfully removed. Also, the controller
features the ability to remotely initiate a continuity test and report the results to further ensure a good
connection.
While utilizing two separate devices allows us to conduct launches while still remaining at a safe
distance from the rocket, it would be worthless if the devices were unable to properly communicate. A
wired connection must be used due to guidelines (if wireless, there is always the risk that the launcher
can pick up an errant signal and misinterprets it as a launch signal) so therefore we elected to forgo
microcontrollers and rely on system of transistors and relays. While it may seem redundant to use
transistors that then activate resistors, this allows us to not have to worry about the distance that we
are launching at. Transistors, which can be activated with a relatively small current, alone are not able to
handle the high level of current needed for a launch attempt (up to 6 amps).The relays on the other
hand are easily able to handle this current load but require a rather high current to be activated which
can be difficult to achieve over long distances due to the resistivity of wires. By combining the two
different components, we are able to use each component’s strength to fix the other’s weakness. This
will allow a secure and reliable connection no matter the distance separating the launcher and
controller.
The above design has been subjected to multiple rounds of analysis both by members and
mentors of Student Space Systems as well as students and professors outside of the organization and we
are confident that it will fulfill all of its constraints. We would like to thank Element14 for assisting in the
supply of parts which has allowed us to ensure that we can achieve the desired level of quality while
staying within budget. Regular updates will soon resume as the summer build team kicks into gear over
the coming weeks. Until then, live long and prosper.
| Controller2.0.pdf | |
| Launchbox2.0.pdf |
