Continuous human habitation of the Moon is the state aim of many major space-faring nations in the coming decades. Reaching that aim requires many tasks, but one of the most fundamental is feeding those humans. Shipping food consistently from Earth will likely be prohibitively expensive shortly, so DLR, Germany’s space agency, is working on an alternative. This semi-autonomous greenhouse can be used to at least partially feed the astronauts in residence on the Moon. To support that goal, a team of researchers from DLR released a paper about EVE, a robotic arm intended to help automate the operations of the first lunar greenhouse, at the IEEE Aerospace conference in March.

The EDEN Versatile End-effector (or EVE) is only possibly named as an homage to the life-seeking robot from WALL-E. But it is designed to interface with the EDEN LUNA greenhouse, a project at DLR meant to result in a fully functional greenhouse for use on the lunar surface. The advantages of such a greenhouse have been discussed in other articles, but needless to say, the EDEN LUNA is the best-supported project that will likely result in a fully functional system on the Moon when the time is right.

But as any gardener would tell you, greenhouses are a lot of work. And any time an astronaut spends on greenhouse maintenance is time they can’t spend doing other tasks, like scientific research. So, it would be extremely beneficial if there was a robot to assist with greenhouse operations, even if that robot had to be remotely controlled by an operator back on Earth.

Enter EVE, which consists of three main components. The transport rails allow the robot to move to the correct location in the greenhouse. Its robotic “arm” enables the robot to position itself effectively to complete its assigned task, and the end effector can push, pull, pick up, or perform other manual tasks. The system uses about 700W and weighs about 170 kg fully installed.

First, let’s look at the transport trails. It’s actually an off-the-shelf commercial system for use in industrial automation. The eXtended Transport System, made by Beckhoff, an industrial automation company, can be mounted in different configurations. It allows whatever is attached to it to be driven to various locations based on a series of signals that control the “mover” to which the robotic arm would be connected.

The robotic arm is based on DLR’s “This Is Not an Arm” (TINA) project. It has seven degrees of freedom, which allows for precise positioning of its end effector. Each of its three joints has around three electronic controllers for motor control, power management, and communication. It’s supported by a camera system that senses its surroundings and allows remote operators to tell where the end effector is positioned.

The Compliant Low-Cost Antagonistic Servo Hand (CLASH) is the end effector. It has two “fingers” and a “thumb” to grip soft objects using force feedback sensors in its fingertips. It can also sense pressure from other components, such as the hand’s “tendons” and thumb and figure position.

These positioning and end-effector systems can work effectively together to perform the greenhouse’s daily maintenance tasks. For now, at least, it will require a skilled operator to do so, but that operator doesn’t have to be co-located with the greenhouse on the Moon – it could be back on Earth or even on the Lunar Gateway station orbiting above the lunar surface. Continuous operation is essential, though, as the first stages of the permanent occupation of the Moon involve temporary stays, where there will be long stretches with no human inhabitants.

DLR is fully backing the development of the EDEN LUNA greenhouse and the EVE robotic arm. Later this year, EVE will be fully integrated into the greenhouse at the Institute of Space Systems in Bremen, followed by a specially designed facility for the greater LUNA project of ESA/DLR in Cologne. As of now, both EVE and EDEN LUNA seem on track to be put through their paces before officially supporting the continual human occupation of the Moon within the next decade.

Learn More:
Prince et al. – EDEN Versatile End-effector (EVE): An Autonomous Robotic System to Support Food Production on the Moon
UT – Plants Could Grow in Lunar Regolith Using Bacteria
UT – A Greenhouse on the Moon by 2014?
UT – Practical Ideas for Farming on the Moon and Mars

Lead Image:
Greenhouse concept art on the Moon.
Credit – DLR