Can humans live and work on the moon? Not just visit for a few days but stay for decades? A first step in long term presence is to send plants. As seedlings, they can be as sensitive as humans to environmental conditions, sometimes even more so. They carry genetic material that can be damaged by radiation as can that of humans. They can test the lunar environment for us acting as a “canary in a coal mine”.
If we send plants and they thrive, then we probably can. Thriving plants are needed for life support (food, air, water) for colonists. And plants provide psychological comfort, as the popularity of the greenhouses in Antarctica and on the Space Station show.
Good idea, but how can we send plants to the Moon soon? Hitchhiking. Thanks to Google, there are many potential rides to the moon in the near future, with commercial spacecraft companies competing to collect the Google Lunar X-Prize in 2015.
We are constructing a small technology demonstration unit to study germination of plants in lunar gravity and radiation on the Moon. The self-contained habitat will have a mass of about 1 kg and would be a payload on a commercial lunar lander – the Moon Express lander, part of the Google Lunar X-prize competition. After landing in late 2015, water will be added to the seeds in the module and their growth will be monitored for 5-10 days and compared to Earth based controls. Seeds will include Arabidopsis, basil, and turnips. This will be the first life sciences experiment on another world and an important first step in the utilization of plants for human life support. Follow up experiments will improve the technology in the growth module and allow for more extensive plant experiments.
Points of Contact: Chris McKay Arwen Davé Bob Bowman
Science goal: Study germination of plants in lunar gravity and radiation.
ISRU Goal: (In Situ Resource Utilization) Use the natural sunlight on the Moon for plant germination.
Education goal: Create a simple version of the lunar plant growth chamber that can be reproduced in large numbers for use in K-12 education.
Opportunity: The first Moon Express lander late 2015.
Our concept: To develop a very simple sealed growth chamber that can support germination over a 5-10 day period in a spacecraft on the Moon. Filter paper with dissolved nutrients inside the container can support ~100 seeds of Arabidopsis and 10 seeds each of basil and turnips. Upon landing on the Moon a trigger would release a small reservoir of water wetting the filter paper and initiating germination of the seeds. The air in the sealed container would be adequate to for more than 5 days of growth. No additional air supply or air processing would be necessary. The seedlings would be photographed at intervals with sufficient resolution to compare with growth in Earth controls. We would use the natural sunlight on the moon as the source of illumination for plant germination as a first ISRU (in situ resource utilization) demonstration.
Science background Plant growth at Earth gravity has been well studied and there has been a lot of research on plant growth in microgravity on Shuttle and Space Station. Recently, ISS payloads have been able to simulate partial gravity (eg. Kiss et al. 2012, Planta 236, 635-645.). The surface of the Moon however is the only location in which the effects of both lunar gravity and lunar radiation on plant growth can be studied. Eventually human exploration of the Moon will require plant growth systems for life support. Germination is the first step in plant growth and thus forms the focus of this first experiment. We will also look for phototropism and circumnutation. The basic data from the experiment would be the growth rate, expressed as leaf area, over time. This would be extracted from images of the plant growth area. In addition image data would be collected to investigate both phototropism (plant motion in response to changes in position of the light source) and circumnutation (plant circular motion). The growth and movement of the plants on the Moon would be compared to similar data from Earth controls in identical growth units.
Germination Shows that minimum environmental factors for Earth-normal growth are available; sensitive to hazards, temperature, moisture and light.
Phototropism Shows that plants on the Moon responds normally to external environmental cues
Circumnutation Shows that Earth-normal endogenous growth patterns and growth rates are expressed in lunar conditions
Follow-on science: After LPX-0 demonstrates germination and initial growth in lunar gravity and radiation, we anticipate follow on experiments that expand the biological science. These include: 1) long term, over-lunar-night experiments, 2) multi-generation experiments, 3) Diverse plants.
Survival to 14 days demonstrates plants can sprout in the Moon’s radiation environment at 1/6 g. Survival to 60 days demonstrates that sexual reproduction (meiosis) can occur in a lunar environment. Survival to 180 days shows effects of radiation on dominant & recessive genetic traits. Afterwards, the experiment may run for months through multiple generations, increasing science return.