Join the Mars Society Red Eagle Student Engineering Contest January 30th Letter of Intent Deadline
The Barboza Space has a fellowship program for students that might want to participate in this Mars Engineering lander design contest. Contact: Bob Barboza at. Suprschool@aol.com
The Mars Society announced last September the Red Eagle Student Engineering Contest to design a lander capable of delivering a ten metric ton payload safely to the surface of Mars. The competition is open to student teams from around the world. Participants are free to choose any technology to accomplish the mission and need to submit design reports of no more than 50 pages by March 31, 2018.
These contest reports will be evaluated by judges and serve as the basis for a down-select to ten finalists who will be invited to present their work in person at the next International Mars Society Convention in September 2018. The first place winning team will receive a trophy and a $10,000 cash prize. Second through fifth place winners will receive trophies and prizes of $5,000, 3,000, $2000, and $1,000 respectively.
For full contest details and regulations, please click here.
All teams wishing to compete in the Red Eagle contest should submit a letter of intent by email to the Mars Society no later than January 30, 2018. Earlier submission is advantageous, however, as it will insure that you are kept informed of any changes and supplied with the answers to any questions posed by other teams. The letter should include the team name, university or universities participating, and email and postal addresses for at least two team contacts.
Pepper is a humanoid robot by French robotics company Aldebaran Robotics, which is owned by SoftBank, designed with the ability to read emotions. It was introduced in a conference on 5 June 2014, and was showcased in Softbank mobile phone stores in Japan beginning the next day. It was scheduled to be available in February 2015 at a base price of JPY 198,000 ($1,931) at Softbank Mobile stores. Pepper’s emotion comes from the ability to analyze expressions and voice tones. In Japan there is also a monthly fee of $360 that has to be paid over 3 years.
Pepper was launched in the UK in 2016 and there are currently two versions available.
The robot’s head has four microphones, two HD cameras (in the mouth and forehead), and a 3-D depth sensor (behind the eyes). There is a gyroscope in the torso and touch sensors in the head and hands. The mobile base has two sonars, six lasers, three bumper sensors, and a gyroscope.
It is able to run the existing content in the app store designed for Aldebaran’s other robot, Nao.
Pepper is not a functional robot for domestic use. Instead, Pepper is intended “to make people happy”, enhance people’s lives, facilitate relationships, have fun with people and connect people with the outside world. Pepper’s creators hope that independent developers will create new content and uses for Pepper.
Pepper is currently being used as a receptionist at several offices in the UK and is able to identify visitors with the use of facial recognition, send alerts for meeting organisers and arrange for drinks to be made. Pepper is said to be able to chat to prospective clients.
The robot has also been employed at banks and medical facilities in Japan, using applications created by Seikatsu Kakumei.
Pepper is available as a research robot for schools, colleges and universities to teach programming and conduct research into human-robot interactions. In the United Kingdom, it is available through Rapid Electronics Limited for this purpose.
Humanoid robots are now used as research tools in several scientific areas. Bob Barboza wants to train robots to care for astronauts taking the long journey to MARS.
Researchers study the human body structure and behavior (biomechanics) to build humanoid robots. On the other side, the attempt to simulate the human body leads to a better understanding of it. Human cognition is a field of study which is focused on how humans learn from sensory information in order to acquire perceptual and motor skills. This knowledge is used to develop computational models of human behavior and it has been improving over time.
It has been suggested that very advanced robotics will facilitate the enhancement of ordinary humans. See transhumanism.
Although the initial aim of humanoid research was to build better orthosis and prosthesis for human beings, knowledge has been transferred between both disciplines. A few examples are powered leg prosthesis for neuromuscularly impaired, ankle-foot orthosis, biological realistic leg prosthesis and forearm prosthesis.
Besides the research, humanoid robots are being developed to perform human tasks like personal assistance, through which they should be able to assist the sick and elderly, and dirty or dangerous jobs. Humanoids are also suitable for some procedurally-based vocations, such as reception-desk administrators and automotive manufacturing line workers. In essence, since they can use tools and operate equipment and vehicles designed for the human form, humanoids could theoretically perform any task a human being can, so long as they have the proper software. However, the complexity of doing so is immense.
They are also becoming increasingly popular as entertainers. For example, Ursula, a female robot, sings, plays music, dances and speaks to her audiences at Universal Studios. Several Disney theme park shows utilize animatronic robots that look, move and speak much like human beings. Although these robots look realistic, they have no cognition or physical autonomy. Various humanoid robots and their possible applications in daily life are featured in an independent documentary film called Plug & Pray, which was released in 2010.
A sensor is a device that measures some attribute of the world. Being one of the three primitives of robotics (besides planning and control), sensing plays an important role in robotic paradigms.
Sensors can be classified according to the physical process with which they work or according to the type of measurement information that they give as output. In this case, the second approach was used.
Proprioceptive sensors sense the position, the orientation and the speed of the humanoid’s body and joints.
In human beings the otoliths and semi-circular canals (in the inner ear) are used to maintain balance and orientation. In addition humans use their own proprioceptive sensors (e.g. touch, muscle extension, limb position) to help with their orientation. Humanoid robots use accelerometers to measure the acceleration, from which velocity can be calculated by integration; tilt sensors to measure inclination; force sensors placed in robot’s hands and feet to measure contact force with environment; position sensors, that indicate the actual position of the robot (from which the velocity can be calculated by derivation) or even speed sensors.
Arrays of tactels can be used to provide data on what has been touched. The Shadow Hand uses an array of 34 tactels arranged beneath its polyurethane skin on each finger tip. Tactile sensors also provide information about forces and torques transferred between the robot and other objects.
Vision refers to processing data from any modality which uses the electromagnetic spectrum to produce an image. In humanoid robots it is used to recognize objects and determine their properties. Vision sensors work most similarly to the eyes of human beings. Most humanoid robots use CCD cameras as vision sensors.
Sound sensors allow humanoid robots to hear speech and environmental sounds, and perform as the ears of the human being. Microphones are usually used for this task.
Actuators are the motors responsible for motion in the robot.
Humanoid robots are constructed in such a way that they mimic the human body, so they use actuators that perform like muscles and joints, though with a different structure. To achieve the same effect as human motion, humanoid robots use mainly rotary actuators. They can be either electric, pneumatic, hydraulic, piezoelectric or ultrasonic.
Hydraulic and electric actuators have a very rigid behavior and can only be made to act in a compliant manner through the use of relatively complex feedback control strategies. While electric coreless motor actuators are better suited for high speed and low load applications, hydraulic ones operate well at low speed and high load applications.
Piezoelectric actuators generate a small movement with a high force capability when voltage is applied. They can be used for ultra-precise positioning and for generating and handling high forces or pressures in static or dynamic situations.
Ultrasonic actuators are designed to produce movements in a micrometer order at ultrasonic frequencies (over 20 kHz). They are useful for controlling vibration, positioning applications and quick switching.
Pneumatic actuators operate on the basis of gascompressibility. As they are inflated, they expand along the axis, and as they deflate, they contract. If one end is fixed, the other will move in a linear trajectory. These actuators are intended for low speed and low/medium load applications. Between pneumatic actuators there are: cylinders, bellows, pneumatic engines, pneumatic stepper motors and pneumatic artificial muscles.
In planning and control, the essential difference between humanoids and other kinds of robots (like industrial ones) is that the movement of the robot has to be human-like, using legged locomotion, especially bipedgait. The ideal planning for humanoid movements during normal walking should result in minimum energy consumption, as it does in the human body. For this reason, studies on dynamics and control of these kinds of structures has become increasingly important.
The question of walking biped robots stabilization on the surface is of great importance. Maintenance of the robot’s gravity center over the center of bearing area for providing a stable position can be chosen as a goal of control.
To maintain dynamic balance during the walk, a robot needs information about contact force and its current and desired motion. The solution to this problem relies on a major concept, the Zero Moment Point (ZMP).
Another characteristic of humanoid robots is that they move, gather information (using sensors) on the “real world” and interact with it. They don’t stay still like factory manipulators and other robots that work in highly structured environments. To allow humanoids to move in complex environments, planning and control must focus on self-collision detection, path planning and obstacle avoidance.
Humanoid robots do not yet have some features of the human body. They include structures with variable flexibility, which provide safety (to the robot itself and to the people), and redundancy of movements, i.e. more degrees of freedom and therefore wide task availability. Although these characteristics are desirable to humanoid robots, they will bring more complexity and new problems to planning and control. The field of whole-body control deals with these issues and addresses the proper coordination of numerous degrees of freedom, e.g. to realize several control tasks simultaneously while following a given order of priority.
“If you are on your way to Mars and your space toilets are broken and cannot be repaired your Mars crew will die.” Bob Barboza, Jr. Astronaut Training Director
A space toilet, or zero gravity toilet, is a toilet that can be used in a weightless environment. In the absence of weight, the collection and retention of liquid and solid waste is directed by use of air flow. Since the air used to direct the waste is returned to the cabin, it is filtered beforehand to control odor and cleanse bacteria. In older systems, waste water is vented into space, and any solids are compressed and stored for removal upon landing. More modern systems expose solid waste to vacuum pressures to kill bacteria, which prevents odor problems and kills pathogens.
When humans travel into space, the absence of gravity causes fluids to distribute uniformly around their bodies. Their kidneys detect the fluid movement and a physiological reaction causes the humans to need to relieve themselves within two hours of departure from Earth. As a result, the space toilet has been the first device activated on shuttle flights, after astronauts unbuckle themselves.
Diagram of the elements of the Space Shuttle WCS
There are four basic parts in a space toilet: the liquid waste vacuum tube, the vacuum chamber, the waste storage drawers, and the solid waste collection bags. The liquid waste vacuum tube is a 2 to 3-foot (0.91 m) long rubber or plastic hose that is attached to the vacuum chamber and connected to a fan that provides suction. At the end of the tube there is a detachable urine receptacle, which come in different versions for male and female astronauts. The male urine receptacle is a plastic funnel two to three inches in width and about four inches deep. A male astronaut urinates directly into the funnel from a distance of two or three inches away. The female funnel is oval and is two inches by four inches wide at the rim. Near the funnel’s rim are small holes or slits that allow air movement to prevent excessive suction. The vacuum chamber is a cylinder about 1-foot (0.30 m) deep and six inches wide with clips on the rim where waste collection bags may be attached and a fan that provides suction. Urine is pumped into and stored in waste storage drawers. Solid waste is stored in a detachable bag made of a special fabric that lets gas (but not liquid or solid) escape, a feature that allows the fan at the back of the vacuum chamber to pull the waste into the bag. When the astronaut is finished, he or she then twists the bag and places it in a waste storage drawer. Samples of urine and solid waste are frozen and taken to Earth for testing.
Toilet device on Soyuz spacecraft
Space Shuttle Waste Collection System
Mission Specialist Claude Nicollier reviews the repair manual for the WCS on STS-46
The toilet used on the Space Shuttle is called the Waste Collection System (WCS). In addition to air flow, it also uses rotating fans to distribute solid waste for in-flight storage. Solid waste is distributed in a cylindrical container which is then exposed to vacuum to dry the waste. Liquid waste is vented to space. During STS-46, one of the fans malfunctioned, and crew member Claude Nicollier was required to perform in-flight maintenance (IFM). An earlier, complete failure, on the eight-day STS-3 test flight, forced its two-man crew (Jack Lousma and Gordon Fullerton) to use a fecal containment device (FCD) for waste elimination and disposal.
International Space Station
There are two toilets on the International Space Station, located in the Zvezda and Tranquility modules. They use a fan-driven suction system similar to the Space Shuttle WCS. Liquid waste is collected in 20-litre (5.3 US gal) containers. Solid waste is collected in individual micro-perforated bags which are stored in an aluminum container. Full containers are transferred to Progress for disposal. An additional Waste and Hygiene Compartment is part of the Tranquility module launched in 2010. In 2007, NASA purchased a Russian-made toilet similar to the one already aboard ISS rather than develop one internally.
On May 21, 2008, the gas liquid separator pump failed on the 7-year-old toilet in Zvezda, although the solid waste portion was still functioning. The crew attempted to replace various parts, but was unable to repair the malfunctioning part. In the interim, they used a manual mode for urine collection. The crew had other options: to use the toilet on the Soyuz transport module (which only has capacity for a few days of use) or to use urine-collection bags as needed. A replacement pump was sent from Russia in a diplomatic pouch so that Space Shuttle Discoverycould take it to the station as part of mission STS-124 on June 2.
While the Soyuz spacecraft had an onboard toilet facility since its introduction in 1967 (due to the additional space in the Orbital Module), all Gemini and Apollo spacecraft required astronauts to urinate in a so-called “relief tube” in which the contents were dumped into space (an example would be the urine dump scene in the movie Apollo 13), while fecal matter was collected in specially-designed bags. The facilities were so uncomfortable that, to avoid using them, astronauts ate less than half the available food on their flights. The Skylab space station, used by NASA between May 1973 and March 1974, had an onboard WCS facility which served as a prototype for the Shuttle’s WCS, but also featured an onboard shower facility. The Skylab toilet, which was designed and built by the Fairchild Republic Corp. on Long Island, was primarily a medical system to collect and return to Earth samples of urine, feces and vomit so that calcium balance in astronauts could be studied.
Even with the facilities, astronauts and cosmonauts for both launch systems employ pre-launch bowel clearing and low-residue diets to minimize the need for defecation. The Soyuz toilet has been used on a return mission from Mir.
NPP Zvezda is a Russian developer of space equipment, which includes zero-gravity toilets.
A next-generation space toilet called the Universal Waste Management System (UWMS) is being developed by NASA for Orion and other long duration missions. It is planned to be quieter, lighter, more reliable, more hygienic and more compact than previous systems. A flight test article of the UWMS is planned to be delivered and tested on the ISS in 2018.
The Barboza Space Center is exploring how to simulate the repairing of space toilets.
The Scoop on Space Poop: How Astronauts Go Potty
By Megan Gannon, News Editor |
On May 5, 1961, NASA astronaut Alan Shepard was locked into his capsule Freedom 7, ready to become the first American and second person ever in space. But before his 15-minute historic flight, Shepard would sit through five hours of delays — and he really had to go to the bathroom.
“Man, I got to pee,” he radioed launch control.
NASA officials weren’t prepared for this situation. They thought the mission would be short enough to avoid it, and lettingAlan Shepardurinate in his shiny silver spacesuit was not something they were ready to do; the astronaut was wired with medical sensors that might get wrecked if wet. But eventually, launch control had no choice but to let him to go.
“You think it’s glamorous being an astronaut? It’s a lot of hard work and a lot of indignity as well,” Mark Roberts, a tour guide at the Intrepid Sea, Air & Space Museum in New York City, said during the museum’s recent summer SpaceFest last month. [Space Toilet Technique: NASA’s How-To Guide (Video)]
After Shepard’s debacle, NASA devised better ways to take care of basic bodily functions. But space waste continued the plague the agency.
By the time astronaut Gordon Cooper launched on the lastProject Mercuryflight in 1963, NASA had created a urine collection device that astronauts could wear inside the one-person spacecraft. Cooper’s flight was not an easy one. Near the end of his 22-orbit 34-hour mission, system after system in his capsule mysteriously started failing. He had to take over manual control and pilot the craft through a risky re-entry into the atmosphere.
What went wrong? An investigation showed that his urine bag leaked and droplets got into the electronics, hobbling his automatic systems, Roberts said.
If rogue urine sounds problematic, think about the agony floating feces could inflict inside a cramped space capsule. When NASA started planning longer missions, they had to take astronauts’ bowels into consideration.
The space agency’s next project, Gemini, put two astronauts side-by-side in a spacecraft, testing out the crucial maneuvers that would bring the Apollo spaceflyers to the moon. To show that humans could survive in space for two weeks,Jim Lovelland Frank Borman spent 14 days flying in Gemini 7, the longest manned mission at the time.
“They had no toilet in there,” Roberts said. “What they had was basically a plastic bag every time they had to do a No. 2.”
Space toilets didn’t become much more sophisticated by the time the first Apollo missions launched. Astronauts like Buzz Aldrin andNeil Armstronghad fecal collection bags that stuck to their bottoms with adhesive when they had to go. And microgravity could make things messy.
“There’s a problem of separation,” Roberts said. “Whatever comes out of you doesn’t know it’s supposed to come away from you.” Each fecal collection bag came with a “finger cot” to allow the astronauts to manually move things along. Then they had to knead a germicide into their waste so that gas-expelling bacteria wouldn’t flourish inside the sealed bag and cause it to explode. [Space Quiz! The Reality of Life in Orbit]
The entire ordeal often took 45 minutes to an hour to complete in the Apollo spacecraft, Roberts said. To minimize their bowel movements, astronauts had a high-protein, low-residue diet — think steak and eggs and other foods that are don’t make a lot of waste after they are absorbed by the body.
Urinating wasn’t much easier for theApollocrews. Their urine collection device was basically a condom-like pouch attached to a hose that vented out into the vacuum of space at the turn of a valve. By the astronauts’ own accounts, it was more than a little unsettling to use the device, Roberts said.
Astronaut potty training
Today, going to the bathroom in space is much less tedious, but it still requires careful attention — and evenspace toilet training. The reusable space planes of NASA’s retired shuttle program had toilets using airflow to draw waste away from the body in place of Earth’s gravity. The International Space Station has commodes with a similar design.
“For No. 2, it’s kind of like a camp potty, where you use that to contain the solid waste and that gets burned up in the atmosphere eventually on a spacecraft,” NASA astronaut Nicole Stott told elementary students today (Aug. 29) during a video chat from NASA’s International Space Station Mission Control in Houston. “For No. 1, it’s basically a hose, we call it a urine hose, that has a vacuum on it.”
Astronauts go through “positional training” on Earth to make sure solid waste goes directly into the narrow opening of these space toilets, Roberts explained. The mock toilet has a camera at the bottom. Astronauts don’t actually go to the bathroom during training, but by watching a video screen in front of them, they can check that their alignment is spot on.
“If you get stuff around these air vents that are providing the suction in there, things can get really clogged up and you can damage a multimillion-dollar toilet fairly easily,” Roberts said.
Breaking a toilet is indeed expensive and inconvenient — not to mention unhealthy. After the sole toilet on the International Space Station had been plagued by a series of problems and breakdowns, NASA bought a second,$19 million Russian commodethat was installed in the orbiting outpost’s U.S. segment in 2008.
As for peeing, each astronaut is given his or her own funnel — made in different shapes for men and women — which attaches to a hose on the toilet. But as gravity diminishes in space, ego apparently doesn’t.
“They had three different sizes of funnels and the guys were always choosing the largest size,” Roberts said of the astronauts in the shuttle program.
Waste not, want not
In 1986, the Soviet Union built theMir space station, which had a bathroom with a toilet that vented the waste out into space. By the time space officials were retiring Mir in 2001, the space station’s solar panels had lost about 40 percent of their effectiveness, Roberts said.
“They realized that a large part of the damage to these solar panels was frozen urine floating in space at very high speeds,” Roberts told his audience.
Today on the International Space Station, a $100 billion orbiting outpost that has been staffed with rotating crews since 2000, urine gets recycled into drinking water through a filtration system.
Fecal matter, meanwhile, often gets packed up and cast off from the space station with other trash in capsules that burn up in the atmosphere, Roberts said. But with longer missions, like flights to Mars, some researchers are thinking about how to recycle feces, too. For example, some scientists propose thathuman waste could line the walls of future spacecraftto act like a radiation shield, protecting astronauts from the harmful effects of cosmic rays.
We live in interesting times with regard to human Mars exploration. I can’t remember a period in which the issue of humans-to-Mars has been so front and center, both in terms of significant progress being made with the actual Mars launch infrastructure, engineering and planning, as well as growing public discussion and excitement about the possibility of humans going to the Red Planet. Things are definitely happening, and the Mars Society is pleased to be an active leader in this historic endeavor.
Elon Musk’s vision and leadership have electrified millions of people, not only in the U.S. but around the world, letting our global community see for the first time that humans to Mars is not just a down-the-line dream, but a goal that humanity can reach in the near term.
The development of heavy lift capability to move equipment, supplies and most importantly large-scale infrastructure to the Martian surface is well underway, with a number of major aerospace companies, including SpaceX (Falcon Heavy), Boeing (SLS) and Blue Origin (New Glenn), leading the way.
From news reporting and film production to academic studies and television advertising, the notion of humans-to-Mars is making serious inroads with the world-wide consciousness. The recent blockbuster film, The Martian, had a major impact on people and provided a realistic cinematic vision of how a human mission to the Red Planet could take place. This has now been followed up by National Geographic’s impressive MARS global event series, the second season of which will soon broadcast on television and online in many languages around the world.
As the largest and most influential space advocacy group dedicated to the human exploration and settlement of the Red Planet, the Mars Society intends to take advantage of this flourishing public interest in Mars by expanding its important work, including:
Mars surface simulation research and studies in Utah and Canada, including our ongoing Mars mission simulation at the Mars Desert Research Station (MDRS), expeditions to the Flashline Mars Arctic Research Station (FMARS) and the continuing expansion of the MDRS facility.
Further development of our Rover Challenge Series, to multiple contests in many countries involving high school and university students.
The Red Eagle student engineering contest to eliminate a key tall pole for human Mars exploration by designing a lander capable of delivering 10 tons to the Martian surface.
Public outreach and educational programming, including promotion of STEM studies through several new projects.
With the involvement of our growing Mars Society advocacy network, we look forward to working with the new NASA administrator in helping shape the future of the U.S. human space program and encourage a dramatic acceleration of the nation’s drive for Mars.
People are talking about the prospects for a human mission to Mars: not just the usual suspects, but also entrepreneurs and many more who have finally realized that humanity’s future in space, beginning with a permanent human presence on Mars, is now within reach.
This needs to be organized to produce concrete results. That is why it is so important we continue to build on the work of the Mars Society in insisting that the initiation of human exploration of the Red Planet be made a true national goal – not just a dream for the future, but as a grand achievement for our time.
But we cannot do this without your help. Please join us in the fight for America’s goal to send humans to Mars. Support the Mars Society by visiting our web site to make as generous a contribution as you can. I thank you for your continuing support and involvement. Together, we can make it a prosperous new year for Mars!
I want to wish all of you a Merry Christmas and Happy Holidays for 2018. One day we hope to be sending greetings cards from Mars and beyond. You can follow our work with students at www.BarbozaSpaceCenter.WordPress.com.
When humans will settle on the moon or Mars they will have to eat there. Food may be flown in. An alternative could be to cultivate plants at the site itself, preferably in native soils. We report on the first large-scale controlled experiment to investigate the possibility of growing plants in Mars and moon soil simulants. The results show that plants are able to germinate and grow on both Martian and moon soil simulant for a period of 50 days without any addition of nutrients. Growth and flowering on Mars regolith simulant was much better than on moon regolith simulant and even slightly better than on our control nutrient poor river soil. Reflexed stonecrop (a wild plant); the crops tomato, wheat, and cress; and the green manure species field mustard performed particularly well. The latter three flowered, and cress and field mustard also produced seeds. Our results show that in principle it is possible to grow crops and other plant species in Martian and Lunar soil simulants. However, many questions remain about the simulants’ water carrying capacity and other physical characteristics and also whether the simulants are representative of the real soils.
Citation: Wamelink GWW, Frissel JY, Krijnen WHJ, Verwoert MR, Goedhart PW (2014) Can Plants Grow on Mars and the Moon: A Growth Experiment on Mars and Moon Soil Simulants. PLoS ONE 9(8): e103138. https://doi.org/10.1371/journal.pone.0103138
Editor: Alberto de la Fuente, Leibniz-Institute for Farm Animal Biology (FBN), Germany
Received: January 8, 2014; Accepted: June 25, 2014; Published: August 27, 2014
Funding: This research was supported by the Dutch Ministery of Economic Affairs. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
Lunar and Mars explorations have provided information about the mineral composition of the soils of these solar objects. In addition to rocks they contain large amounts of sand-like soils or regoliths. All essential minerals for the growth of plants appear to be present in sufficient quantities in both soils probably with the exception of reactive nitrogen. Nitrogen in reactive form (NO3, NH4) is one of the essential minerals necessary for almost all plant growth . The major source of reactive nitrogen on Earth is the mineralisation of organic matter . However organic matter is absent on both Mars and moon although they do contain carbon –. Nitrogen in reactive form (NO3, NH4) is one of the essential minerals necessary for almost all plant growth . Reactive nitrogen is part of the material in our solar system and is part of solar wind, a source of reactive nitrogen on the moon and Mars , . Reactive nitrogen may also arise as an effect of lightning or volcanic activity ,  and both processes may occur on Mars. This indicates that in principle reactive nitrogen could be present , . However, the Mars Pathfinder was not able to detect reactive nitrogen . Thus the actual presence of major quantities of reactive nitrogen remains uncertain. The major source of reactive nitrogen on Earth is the mineralisation of organic matter , which is absent on both Mars and moon. The absence of sufficient reactive nitrogen may be solved by using nitrogen fixing species. In symbioses with bacteria ,  these nitrogen fixers are able to bind nitrogen from the air and transform it into nitrates, a process which requires nitrogen in the atmosphere. However, there is no atmosphere on the moon, and on Mars it is only minimally present and contains traces of nitrogen. Metals like aluminium and chromium are also present in the extra-terrestrial soils. Aluminium is known to disturb plant growth and even lead to plant death . Another essential for plant growth is liquid water. Liquid water is not (moon) or possibly very limited present (Mars). Ice is present on both Mars and moon, and could be used after harvest –. Many plant species may be grown on water cultures, e.g. tomatoes or paprika, but not all. Therefore, local soils could be used to grow crops, at least partly.
During the Apollo project there has been no experiment with plant growth on the moon. However experiments on earth have been carried out with the brought back moon material. These experiments did not include growth of plants on moon soil. Instead plants were exposed to moon stones by rubbing them and even small amounts were added to growth medium. These experiments indicated that there were no toxic effects of moon soil on short term plant growth , for an overview see Ferl and Paul . Ferl and Paul  also provide pictures of the model plant Arabidopsis thaliana grown on a moon regolith simulant (JSC1a). Studies with moon rock simulant (anorthosite) were carried out with the model plant Tagetes patula, . These studies revealed that these plants were able to grow with and without the addition of bacteria , , and that plants were able to blossom . There have been plant growth experiments with Mars regolith simulant as well. Experiments with bacteria on Mars soil simulant revealed that growth is possible, including nitrogen fixing bacteria .
Our goal was to investigate whether or not species of the three groups wild plants, crops and nitrogen fixers (Table 1), would germinate and live long enough to go through the first stages of plant development on artificial Mars and moon regoliths. If this would be the case it is conceivable that plant growth is possible within an artificial surrounding on Mars and moon surface, although our experiment was conducted on Earth with its deviating gravity. Moreover, we assumed that plant cultivation will be carried out in closed surroundings with Earth like light and atmospheric conditions.
Mars and moon regolith simulant were purchased from Orbitec (http://www.orbitec.com). Both regoliths were manufactured by NASA (for Mars we used JSC-1A Mars regolith simulant, for Moon we used the JSC1-1A lunar regolith simulant) , . Since the Mars and moon regolith simulants are comparable to Earth soils, at least in mineral composition –, they can be mimicked by using volcanic Earth soils, as has been done by NASA , .
As a control we used coarse river Rhine soil from 10 m deep layers which is nutrient poor, and free from organic matter and seeds. Since the moon and Mars simulants had only been analysed for mineral content and particle size, we also analysed them for nutrients that are available for plant species. All three soil types were analysed for soil pH water, Organic matter content, Total N and P content (both destructive), NH4, NO2+, NO3, PO4, Al, Fe, K and Cr (all seven in CaCl2 extract). All analyses were repeated two times according to standard protocol (RvA-accreditation for test laboratories; registration number scope: 342). These soil parameters are typically used to explain species occurrence on Earth .
The analysis revealed that the moon regolith simulant is truly nutrient poor, though it contains a small amount of nitrates and ammonium. The Mars regolith simulant also contains traces of nitrates of ammonium, and also a significant amount of carbon (Table 2). The pH of all three soils is high. The pH of the moon regolith is that high that it may be problematic for many plant species, especially for crops . We applied the regoliths and the control earth sand as supplied, the sands were not sterilised, since sterilisation may alter its properties.
Species were selected from three groups: four different crops, four nitrogen fixers and six wild plants which occur naturally in the Netherlands (Table 1). Only species with relatively small seeds were chosen so that the nutrient stock in the seeds would be quickly depleted and the plant becomes totally dependent on what is available in the soils for its growth. For the wild plants we chose species that are able to grow either under nutrient poor circumstances or under a wide range of circumstances (see Table 1) based on the responses of the species to abiotic conditions , . Note that although species may have limits for growth conditions in the field they are often able to grow in monocultures under different circumstances, e.g. more nutrient rich or nutrient poor conditions, because of lack of more competitive species. To be able to monitor the first growth stages we used seeds of the species. The crop and nitrogen fixer seed were bought at the local shop (Welkoop, Wageningen), and the wild plant seeds at Cruydt Hoeck (Nijeberkoop). The latter seeds were collected in the field. Externally present bacteria on the seeds, if any, were not killed.
Experimental design and observations
Small pots were filled with 100 g moon soil simulant, 100 g Earth soil or 50 g Mars soil simulant and 25 g demineralized water was added to each pot. The mass of the simulants added was different since we wanted to fill the pots with approximately the same volume to have the same column height. A filter was placed on the bottom of each pot to prevent soil from leaking. For each soil type and plant species twenty replica pots were used. This resulted in 840 pots (3 soils×14 species×20 replicas). In each pot we positioned five seeds, giving 100 seeds per species – soil combination. The pots were placed in a glasshouse in a completely randomized block design where each block constitutes a replicate (Fig. 1). Each pot was placed in a petri dish (without cap) to hold excessive water and to prevent roots growing into other pots. The pots were placed on a large table in the glasshouse (Fig. 2).
Figure 2. Block 2 of the experiment, with randomly placed pots, 14 days after the start of the experiment.
Each block contains 42 pots. Block 12 is visible in the background. The labels in the pots show the pot number, the species (from left to right on the first row Yellow sweet clover (twice), Leopards bane, Field Mustard, Carrot and Red fescue) and the soil type (L for moon or Lunar, M for Mars and E for Earth) combined with the block number (2).
The experiment started of April 8th 2013. Temperature in the glasshouse was maintained at around 20°C. During the experimental period average temperature was 21.1±3.02°C and air humidity was 65.0±15.5% both based on 24 hour recording with a 5 minutes interval. Mean day time lasted for 16 hours. If the sunlight intensity was below 150 watt/m2 lamps yielding 80 µmol (HS2000 from Hortilux Schréder) were switched on. The pots were watered once or twice a day depending on the evaporation rate by spraying with demineralised water (about 10 litres for the whole experiment for each occasion). We used demineralized water to mimic water from Mars and moon and to prevent pollution with (for example) nutrients that are present in tap water. Ambient air was used.
Seeds were scored on germination, first leaf production, bud forming, flowering and seed setting. At the end of the experiment, 50 days after April 8th, total biomass was harvested and, after cleaning, dried in a stove for 24 hours at 70°C; After cooling down above and below ground biomass were weighed separately. For 25 experimental units the total biomass was smaller than the weighting limit. For those units a value of 0.5 mg (for plants that germinated, but could not be recovered at the end of the experiment) or 0.1 mg (for plants that died before the end of the experiment directly after germination) was assigned to the total biomass. Above and below ground biomass was set to half this value. For 21 units the above ground biomass was smaller than the weighting limit and this was also true for the below ground biomass of 25 units. In these cases the corresponding biomass was set to 0.1 mg.
Logistic regression was used to statistically analyse the number of germinated seeds in each pot, as well as the number of seeds which developed leaves, which developed flowers (including buds), and the numbers of plants which were still alive after 50 days. A pairwise likelihood ratio test, separately for each species and accounting for differences between blocks, was employed to test whether Earth, moon and Mars soil simulants give different results. When necessary, overdispersion was accounted for by inflating the binomial variance by an unknown factor and then using quasi likelihood rather than maximum likelihood .
An analysis of variance, again separately for each species and accounting for block effects, was performed on the logarithm of the total, above and below ground biomass, as well as on the ratio of the above and below ground biomass. The log transform was employed because this stabilizes the variance. Pairwise difference t-test between the soil types were carried out. Note that this is a conditional analysis since units with no biomass are excluded. This implies that no biomass is given for V. sativa sativa on the moon because none of these seeds germinated.
Common vetch, a nitrogen fixer, did not germinate on moon soil. All other plant species did germinate with different proportions on all soils (Fig. 3; background information can be found in Table S1 and S2). In general the germination percentage on Martian soil simulant is highest and lowest on the moon soil simulant (Fig. 3). On average the four crop species have the highest germination percentages, although some species (Reflexed stonecrop, Red fescue, Yellow sweet clover and Greater birds’-foot trefoil) from the other two groups have similar germination percentages. Differences in germination percentages are most likely due to seed quality. The seeds of the crops Carrot, Cress and Tomato are controlled and have a high quality. The seeds of the other species are harvested from the field and except Rye have not been improved by plant breeding. These seed lots may therefore contain less or non-viable seeds. The percentages of plants that form leaves are sometimes considerably lower than the percentages for germination, indicating that some plants stop developing or even die. Leaf forming occurred most on Martian soil simulant and least on moon soil simulant. This trend is also present for species that form flowers or seeds. Only three species reach these stages, Field mustard, Rye and Cress (the last two being crops). Field mustard (only on Mars) and Cress (on Mars and Earth) also formed seeds. For examples see photo 1–10 (File S1). Also for the percentage plants still alive after 50 days, Martian soil simulant performed best and moon soil simulant worst. Martian soil simulant also performed better than Earth soil for most species. Leopards bane, Field mustard and Common vetch had no living plants left after 50 days on moon soil.
Figure 3. Percentage germination, leave formers, plants forming flowers and plants still alive after 50 days per species.
All results are after 50 days and percentages are based on all 100 seeds per plant species-soil type combination Pairwise differences are displayed by a line which joins soil types which are significantly different at the 1% (thin line) and 0.1% (thick line) significance level. Background information can be found in Table S1 and S2.
The biomass at the end of the experiment was significantly higher for eleven out of the fourteen species on Martian soil simulant as compared to both other soils. The biomass for earth and moon soil simulant is often quite similar (Fig. 4), although for nine species the biomass increment on Earth soil was significantly higher than on moon soil simulant. Apparently, in general, plants were able to develop at the same rate on Martian and Earth soil simulants, but biomass increment was much higher on Mars simulant. This is reflected in both below and aboveground biomass, although there are differences at the species level.
Figure 4. Average biomass results per species at the end of the 50 day experiment and the resulting aboveground belowground biomass ratio.
Biomasses are given in mg dry weight on 10 log scale. The triangle indicates an outlier for Lupine (above/below 19.7). For Common vetch there is no ratio given because both above- and belowground biomass are zero. Pairwise differences are displayed by a line which joins soil types which are significantly different at the 1% (thin line) and 0.1% (thick line) significance level. Background information can be found in Table S1 and S2.
We found germination and plant growth for both moon and Mars soil simulants. Our results are in line with earlier research on Arabidopsis thaliana and Tagetes patula– on moon regolith simulant and moon rock simulant, though our results appear to be less promising. Kozyrovska et al.  had blossoming plants of T. patula, where we had only one plant of Sinapsis arvensis that formed a flower butt, but died before flowering.
On average species in Martian soil simulant performed significantly better than plants in Earth soil with respect to biomass increment. Although the Earth soil used, which was coarse and very nutrient poor, is not the best soil to grow crops on, we expected it to perform at least as well as the other two soils. However, in the warmer periods it was difficult to keep the water content in the pots high enough, despite spraying twice a day. The Mars soil simulant resembles loess-like soils from Europe and holds water better than the other two soils. Moon soil simulant dried out fastest. It therefore is essential that further research on the physical characteristics of the extra-terrestrial soils is conducted, as well as the way they could be irrigated. The larger water holding capacity of Martian soil simulant may explain its better performance and, partly, the underperformance of moon soil simulant. The high pH may also explain the lagging growth on the moon soil simulant and also on the Earth soil. Important for plant growth is not only the presence of nutrients, but also the balance between them. Both soils are rather imbalanced for nutrients; where the artificial moon soil lacks nitrates, the artificial soil lacks of phosphate. If nutrients are added in future experiments this imbalance has to be corrected as well, besides the addition of nutrients itself. The presence of a high C-elementary content in the Mars soil simulant is surprising. We also chemically analysed organic matter content in the simulant, but that resulted in obviously wrong results. The standard procedure includes backing the soil at 550°C. The problem is that part of the oxides, especially the iron oxides, evaporates as well, clearly yielding wrong results. Nevertheless a part of the origin of the Carbon content may be from organic matter. It may be a result of the way the soil is ‘harvested’ on Hawaii, leaving traces of organic carbon in the soil. Kral et al.  found traces of organic material in the JSC-1 simulant. It may also partly explain why the Mars soil was able to hold water best, as organic matter is more capable of holding water than bare sand. There is no organic matter on Mars –, as far as we now, so this would make the Mars simulant we used less suitable for experiments to investigate the potential of Mars soil, unless the experiment has as goal to test the potential of the soil after adding organic matter. In our experiment this was the reason to test the legumes. They can be used as green fertilizer and after growth mixed with the soil. Visual inspection of the Mars soil simulant did not reveal large quantities of organic matter. However, further test on the simulant is advisable.
This experiment was carried out in pots. Some of the crops on Mars or moon may be cultivated in pots, but part of the crops may possibly be cultivated in full soil (in growth chambers or under domes). Moist conditions will then be different and may give rise to different results between pots and full soil. It is therefore of interest to conduct future experiments in full soil cultivation as well.
The reason for using nitrogen fixers in our experiment is that they may possibly compensate for the lack of sufficient reactive nitrogen in artificial Martian and moon soil. At the first stage of colonisation, these species can be used to enrich the soils with nitrogen, essential for all other plants, by mixing them with the soil after their growth as is commonly done in the Netherlands in winter –. This may be done in addition to manure brought from Earth or from human faeces. All chosen nitrogen fixers may perform this function; however Common vetch did not perform very well on Martian soil simulant, which may indicate that inoculation with nitrogen fixing bacteria may be necessary. We did not inoculate the soil simulants with nitrogen fixing bacteria in this experiment, although we did not sterilise the simulants nor the seeds. The bacteria could thus be present, but we did not test that in our experiment. In future experiments we will inoculate the soils with these bacteria. The nitrogen fixers may also play a role in detoxifying soils polluted with metals .
Except for Common vetch all other plants germinated in some proportion on all three tested soils; the Mars soil simulant, the moon soil simulant and the River Rhine soil (control). Rye, cress and field mustard flowered, the latter two also formed seeds. Germination and biomass forming differed between species and soil types. The Mars soil simulant gave the highest biomass production, the moon soil simulant the lowest. On the moon soil simulant many germinated plants died or stayed very small. This may be due to the high soil pH, the moist holding capacity and or the free aluminium in the simulant. Our results show that it is in principle possible to grow plants in Martian and Lunar soil simulants although there was only one plant that formed a flower butt on moon soil simulant. Whether this extends to growing plants on Mars or the moon in full soils themselves remains an open question. More research is needed about the representativeness of the simulants, water holding capacity and other physical characteristics of the soils, whether our results extend to growing plants in full soil, the availability of reactive nitrogen on Mars and moon combined with the addition of nutrients and creating a balanced nutrient availability, and the influence of gravity, light and other conditions.
Percentages seeds which germinated, produced leaves, were flowering and were alive after 50 days. P values of pairwise difference tests, separately for each species, are given in the last three columns. P-values smaller than 0.01 are given in bold. All species soil type combinations had 20 replicas and five seeds were positioned in every pot. Note that due to the many replicas small differences are statistically significant.
Percentages seeds which germinated, produced leaves, were flowering and were alive after 50 days. P values of pairwise difference tests, separately for each species, are given in the last three columns. P-values smaller than 0.01 are given in bold. All species soil type combinations had 20 replicas and five seeds were positioned in every pot. Note that due to the many replicas small differences are statistically significant.
Number of seeds that Germinated, formed green leaves, flowered, set seeds, number of plants alive after 50 days, total biomass per pot, below ground biomass per pot and above ground biomass per pot. (see Excel file).
R.M.A. Wegman, T. Busser and M. van Adrichem helped with start of the experiment and the harvest. We thank F. van der Helm and one anonymous reviewer for their helpful comments on a previous version of this manuscript.
Conceived and designed the experiments: GWWW PWG. Performed the experiments: JYF WHJK MRV GWWW. Analyzed the data: GWWW PWG JYF. Wrote the paper: GWWW PWG JYF.
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