xgravler - Experimental Gravity Research with LEGO-based Robotics Onboard a Stratospheric Research Balloon

The REEL-E payload, the final implementation of the xgravler project, measures the g-forces under changing conditions in high altitude environments. For this, the payload was put into a stratospheric research balloon during a mission named H.A.L.E, organized by the University of Reno, Nevada, and sponsored by the NASA Space Grant, Energizer, LEGO and National Instruments. The balloon was launched on 29 July 2008 from the Nevada desert, close to Reno, USA, and reached an altitude of just over 99,500 ft (~30km).

Short Description

This project was realized using a LEGO Mindstorms NXT processor in combination with a three-axis accelerometer (very similar to the one used at a Nintendo Wii Remote), and some additional electronic hardware to execute experiments on micro- gravity (μg) generation in high-altitudes. The main purpose of the mission was to check the feasibility of our idea.

The implementation used two payloads, dubbed REEL and E, connected by a tether and a Bluetooth communication-link. The REEL payload drops E, during which it would experience a few moments of free-fall, and reels it back in. During the free fall the acceleration is measured and then sent back via wireless link. This experiment was repeated 24 times over the course of the balloon flight.

μg is useful for a variety of scientific research areas ranging from crystal formation, biotechnology, medical/drugs research, fluid physics research to the emerging field of nanotechnology. A follow-up mission named reel.SMRT was selected and funded by the European Space Agency (ESA) and the German Aerospace Center (DLR). In 2009 payloads flew on one of the BEXUS balloons.

Project Partners


SpaceMaster Robotics Team, Austria - Jürgen Leitner


SpaceMaster Robotics Team, Mexico - David Leal Martínez

Contact Address

SpaceMaster Robotics Team
Jürgen Leitner
Auhofstraße 18
A-3184 Türnitz
Web: http://smrt.name/