Skyward Experimental Rocketry - Hermes X

About Skyward

Based at the Polytechnic University of Milan in Italy, Skyward Experimental Rocketry is a student association with the ambitious goal of designing, manufacturing and launching experimental sounding rockets.

Founded in 2012, our association now brings together more than a 130 active members from different engineering faculties, working on two simultaneous projects with a renewed goal: EuRoC 2021.

The rocket that will fly in Portugal is an improved version of the one that already flew last year, properly modified to satisfy the competition's requirements.

EuRoc 

­EuRoc – European Rocketry Challenge is the first university rocketry competition in Europe. Promoted by the Portuguese Space Agency and based on the American Spaceport Cup, it challenges engineering students to design, build and launch their own vehicles reaching a 3000 m apogee accurately.

Our Rocket: Hermes_X

Our latest rocket, now in the design phase is the enhanced version of Hermes V0 and Hermes V1,  increased in volume and weight, with new characteristics to make it suitable for the competition. 

Electronics is one of the essential elements of the missile, since it performs crucial functions such as ­reading and saving data for post-mission analysis and sending the command to release the parachutes.

The "Death Stack" is the onboard computer of Hermes X, designed from scratch by our electronics team to satisfy the demanding mission’s requirements.

It is composed of four boards stacked one on top of the other, having different specific tasks.

Boards description 

Analog board 

Since the pressure is the most important information for our apogee detection algorithm and it’s also used in the aerobrakes control algorithm, the analog board mounts 3 different pressure sensors: 

• a single ended analog sensor to measure the static pressure outside the rocket 
• a differential analog sensor to measure the dynamic pressure   
• a digital sensor to measure the pressure inside the rocket.

RF-IMU board 

The 3 IMUs present in this board collect data that allows us to estimate the rocket’s attitude as well as its altitude, necessary for the correct control of the aerobrakes system. 

The data collected by the sensors is then sent to the ground station’s computer by means of an XBEE module, plugged into this board 

The rocket also stores a GPS module that is plugged into this board.

STM board 

This board is the brain of the electronic system. Its main component is the STM32F429 microcontroller, which runs all the control algorithms needed for a successful launch. 

Power board 

This board is responsible for: 

• Converting the 12 V of the LiPo battery into the 5V used by all the other boards by means of a SEPIC converter 
• Driving the servomotors used in the aerobrakes control system and in the nose cone’s expulsion system 
• Driving the system for the parachute’s deployment 

Word to PCBWay

The european competition that we are going to partecipate to is the most ambitious goal our association has ever pursued. We therefore need a manufacturer which is able to provide us the high quality needed for such a delicate application, along with a small production time that allows us to maximize the time window dedicated to our test sessions. Moreover, such a mission requires a quite relevant economic effort, which is often a problem for student associations like ours.

For these reasons we decided to consider PCBWay as our manufacturer, thanks to its possibility to provide us a high quality service while ensuring a small production time and an absolutely favourable price.