Open.Space: An Open Source SDR Based Phased Array for Bouncing Signals off the Moon
Open.space is an upcoming open-source project aiming to unlock affordable earth-moon-earth (EME) bounce communications for the amateur radio public. To achieve this, they have designed a software-defined radio-based tiling system that allows people to easily create phased arrays.
EME (Earth–Moon–Earth) bouncing is a part of the amateur radio hobby that typically involves using (~1m - 3m diameter) high-gain dish antennas to transmit a signal toward the Moon, reflect it off the Moon’s surface, and have it received by a distant contact on Earth with similar hardware.
A phased array consists of a grid or lattice of many small antennas working together in sync. By applying tiny delays between elements and combining their signals, the array can make radio waves add up in one chosen direction and cancel in others. This lets software steer the receive/transmit beam electronically (no motors or moving parts), improving sensitivity and reducing interference. Compared to a dish antenna, it can scan and track targets much faster, form multiple beams if needed, and is compact and low-profile without physically turning. A common phased-array antenna many may have used before is a Starlink antenna.
A single open.space tile consists of a 4x4 MIMO SDR and four antennas. The SDR's frequency range covers 4.9 - 6.0 GHz, and it has 40 MHz of bandwidth via an 8-bit ADC. The tiles can be used on their own as a general SDR, for radio direction finding, as an Open-Wi-Fi router, as a 4G/5G basestation, or for drone HD links and robotics communications.
Multiple tiles can also be combined in a lattice shell to form the "Mini" starter phased array, which consists of 18 tiles. With the Mini phased array, you can achieve 60 degrees of beam steering, up to 34 dBi of gain, and 52.6 dBW of EIRP transmit power. The Mini is not large enough for EME, but upgrading to "Moon", which consists of 60 tiles, makes EME possible. "Moon" gets you 60 degrees of beam steering, up to 39.3 dBi gain, and 63.1 dBW transmit power.
This sounds expensive, but each tile is actually slated to cost only US$49-US$99. The Mini is priced at US$899 - US$1499, and the "Moon" at US$2,499 - US$4,999.
The Open.space hardware has not yet been released for sale, but the website indicates March 2026 as the expected shipping date. You can sign up to their email list on their website for updates.
