When you go on a camping trip, when is it really tough? When are you really roughing it?
It is really tough if there is no supply store and no facilities at the place you are going. If you have to bring everything with you in your car then that makes it tougher.
If there is a gas station, running water and cabins for rent, then it becomes more like a rest stop on the highway.
The moon is a continent-sized place that is cold and difficult. The Moon has frozen ice. What do we do when we seriously want to research a remote continent-sized place that is cold and difficult. The example of that is Antarctica. Antarctica has McMurdo Station and dozens of other research stations.
Advanced propulsion breakthroughs are near. Spacecraft have been stuck at slow chemical rocket speeds for years and weak ion drive for decades. However, speeds over one million miles per hour before 2050 are possible. There are surprising new innovations with technically feasible projects.
NASA Institute for Advanced Concepts (NIAC) is funding two high potential concepts. New ion drives could have ten times better in terms of ISP and power levels ten thousand times higher. Antimatter propulsion and multi-megawatt ion drives are being developed.
Ganymede was shaped by pronounced periods of tectonic activity in the past, according to a new paper. It’s no longer active and its surface is more-or-less frozen in place now. But this discovery opens the door to better planning for future missions to Jupiter’s other frozen moon Europa. Unlike Ganymede, Europa is still tectonically active, and understanding past geological activity on Ganymede helps us understand present-day Europa.
Earlier this week asteroid Ryugu had a visitor. The Mobile Asteroid Surface Scout (MASCOT) landed on Ryugu on October 3rd after it was successfully deployed from the Japanese Hayabusa2 space probe. The little hopping robot’s visit was brief however, and it stopped functioning on Oct. 4th.
In April of 2016, Russian billionaire Yuri Milner announced the creation of Breakthrough Starshot. As part of his non-profit scientific organization (known as Breakthrough Initiatives), the purpose of Starshot was to design a lightsail nanocraft that would be capable of achieving speeds of up to 20% the speed of light and reaching the nearest star system – Alpha Centauri (aka. Rigel Kentaurus) – within our lifetimes.
At this speed – roughly 60,000 km/s (37,282 mps) – the probe would be able to reach Alpha Centauri in 20 years, where it could then capture images of the star and any planets orbiting it. But according to a recent article by Professor Bing Zhang, an astrophysicist from the University of Nevada, researchers could get all kinds of valuable data from Starshot and similar concepts long before they ever reached their destination.
To recap, Breakthrough Starshot seeks to leverage recent technological developments to mount an interstellar mission that will reach another star within a single generation. The spacecraft would consist of an ultra-light nanocraft and a lightsail, the latter of which would accelerated by a ground-based laser array up to speeds of hundreds of kilometers per second.
Such a system would allow the tiny spacecraft to conduct a flyby mission of Alpha Centauri in about 20 years after it is launched, which could then beam home images of possible planets and other scientific data (such as analysis of magnetic fields). Recently, Breakthrough Starshot held an “industry day” where they submitted a Request For Proposals (RFP) to potential bidders to build the laser sail.
According to Zhang, a lightsail-driven nanocraft traveling at a portion of the speed of light would also be a good way to test Einstein’s theory of Special Relativity. Simply put, this law states that the speed of light in a vacuum is constant, regardless of the inertial reference frame or motion of the source. In short, such a spacecraft would be able to take advantage of the features of Special Relativity and provide a new mode to study astronomy.
Based on Einstein’s theory, different objects in different “rest frames” would have different measures of the lengths of space and time. In this sense, an object moving at relativistic speeds would view distant astronomical objects differently as light emissions from these objects would be distorted. Whereas objects in front of the spacecraft would have the wavelength of their light shortened, objects behind it would have them lengthened.
This phenomenon, known as the “Doppler Effect”, results in light being shifted towards the blue end (“blueshift”) or the red end (“redshift”) of the spectrum for approaching and retreating objects, respectively. In 1929, astronomer Edwin Hubble used redshift measurements to determine that distant galaxies were moving away from our own, thus demonstrating that the Universe was in a state of expansion.
Because of this expansion (known as the Hubble Expansion), much of the light in the Universe is redshifted and only measurable in difficult-to-observe infrared wavelengths. But for a camera moving at relativistic speeds, according to Prof. Zhang, this redshifted light would become bluer since the motion of the camera would counteract the effects of cosmic expansion.
This effect, known as “Doppler boosting”, would cause the faint light from the early Universe to be amplified and allow distant objects to be studied in more detail. In this respect, astronomers would be able to study some of the earliest objects in the known Universe, which would offer more clues as to how it evolved over time. As Prof. Zhang explained to Universe Today via email, this would allow for some unique opportunities to test Special Relativity:
“In the rest frame of the camera, the emission of the objects in the hemisphere of the camera motion is blue-shifted. For bright objects with detailed spectral observations from the ground, one can observe them in flight. By comparing their blue-shifted flux at a specific blue-shifted frequency with the flux of the corresponding (de-blueshifted) frequency on the ground, one can precisely test the Doppler boosting prediction in Special Relativity.”
In addition, the frequency and intensity of light – and also the size of distant objects – would also change as far as the observer was concerned. In this respect, the camera would act as a lens and a wide-field camera, magnifying the amount of light it collects and letting astronomers observe more objects within the same field of view. By comparing the observations collected by the camera to those collected by a camera from the ground, astronomers could also test the probe’s Lorentz Factor.
This factor indicates how time, length, and relativistic mass change for an object while that object is moving, which is another prediction of Special Relativity. Last, but not least, Prof. Zhang indicates that probes traveling at relativistic speeds would not need to be sent to any specific destination in order to conduct these tests. As he explained:
“The concept of “relativistic astronomy” is that one does not really need to send the cameras to specific star systems. No need to aim (e.g. to Alpha Centauri system), no need to decelerate. As long as the signal can be transferred back to earth, one can learn a lot of things. Interesting targets include high-redshift galaxies, active galactic nuclei, gamma-ray bursts, and even electromagnetic counterparts of gravitational waves.”
However, there are some drawbacks to this proposal. For starters, the technology behind Starshot is all about accomplishing the dream of countless generations – i.e. reaching another star system (in this case, Alpha Centauri) – within a single generation.
And as Professor Abraham Loeb – the Frank B. Baird Jr. Professor of Science at Harvard University and the Chair and the Breakthrough Starshot Committee – told Universe Today via email, what Prof. Zhang is proposing can be accomplished by other means:
>“Indeed, there are benefits to having a camera move near the speed of light toward faint sources, such as the most distant dwarf galaxies in the early universe. But the cost of launching a camera to the required speed would be far greater than building the next generation of large telescopes which will provide us with a similar sensitivity. Similarly, the goal of testing special relativity can be accomplished at a much lower cost.”
Of course, it will be many years before a project like Starshot can be mounted, and many challenges need to be addressed in the meantime. But it is exciting to know that in meantime, scientific applications can be found for such a mission that go beyond exploration. In a few decades, when the mission begins to make the journey to Alpha Centauri, perhaps it will also be able to conduct tests on Special Relativity and other physical laws while in transit.
It’s been over forty years since the Apollo Program wrapped up and the last crewed mission to the Moon took place. But in the coming years and decades, multiple space agencies plan to conduct crewed missions to the lunar surface. These includes NASA’s desire to return to the Moon, the ESA’s proposal to create an international Moon village, and the Chinese and Russian plans to send their first astronauts to the Moon.
For this reason, a great deal of research has been dedicated to what the health effects of long-duration missions to the Moon may be – particularly the effects a lower gravity environment would have on the human body. But in a recent study, a team of pharmacologists, geneticists and geoscientists consider how being exposed to lunar dust could have a serious effect on future astronauts’ lungs.
Because it has no atmosphere, the Moon’s surface has been pounded by meteors and micrometeroes for billions of years, which have created a fine layer of surface dust known as regolith. In addition, the Moon’s surface is constantly being bombarded by charged particles from the Sun, which cause the lunar soil to become electrostatically charged and stick to clothing.
Indications that lunar dust could cause health problems first emerged during the Apollo missions. After visiting the Moon, astronauts brought lunar soil back with them into the command module as it clung to their spacesuits. After inhaling the dust, Apollo 17 astronaut Harrison Schmitt described having symptoms akin to hay fever, which including sneezing, watery eyes and a sore throat.
While the symptoms were short-lived, researchers wanted to know what the long-term effects of lunar dust could be. There have also been indications that exposure to lunar dust could be harmful based on research that has shown how breathing dust from volcanic eruptions, dust storms and coal mines can cause bronchitis, wheezing, eye irritation and scarring of lung tissue.
Previous research has also shown that dust can cause damage to cells’ DNA, which can cause mutations and eventually lead to cancer. For these reasons, Caston and her colleagues were well-motivated to see what harmful effects lunar soil could have on the human body. For the sake of their study, the team exposed human lung cells and mouse brain cells to samples of simulated lunar soil.
These simulants were created by using dust samples from Earth that resemble soil found on the Moon’s lunar highlands and volcanic plains, which were then ground to a fine powder. What they found was that up to 90% of human lung cells and mouse neurons died when exposed to the dust samples. The simulants also caused significant DNA damage to mouse neurons, and the human lung cells were so effectively damaged that it was impossible to measure any damage to the cells’ DNA.
The results show that breathing lunar dust (even in minute quantities) could pose a serious health hazard to astronauts traveling to any airless bodies in the future. This includes not only the Moon, but also Mars and other terrestrial bodies like Mercury. Until now, this health hazard has been largely overlooked by space agencies seeking to understand the long-term health risks of space travel.
“There are risks to extraterrestrial exploration, both lunar and beyond, more than just the immediate risks of space itself,” said Rachel Caston. According to Bruce Demple, a biochemist at Stony Brook University School of Medicine and senior author of the new study, their results (coupled with the experience of the Apollo astronauts) indicate that prolonged exposure to lunar dust could impair airway and lung function.
What’s worse, he also indicated that if the dust induces inflammation in the lungs, it could increase the risk of more serious diseases like cancer. “If there are trips back to the Moon that involve stays of weeks, months or even longer, it probably won’t be possible to eliminate that risk completely,” he said.
Ergo, any attempts to mitigate the risks of mounting crewed missions to the Moon, Mars, and beyond will have to take into account exposure to not only low-gravity and radiation, but also electrostatically charged soil. Aside from limiting the duration of missions and the number of EVAs, certain protective counter-measures may need to be incorporated into any plans for long-duration missions.
One possibility is to have astronauts cycle through an airlock that would also spray their suits with water or a compound designed to neutralize the charge, thus washing them clean of dust before they enter the main habitat. Otherwise, astronauts working in the International Lunar Village (or any other off-world habitat for that matter) may have to wear breathing masks the entire time they are not in a spacesuit.
The Moon and Mars will probably be the first places in the Solar System that humanity will try to live after leaving the safety and security of Earth. But those worlds are still incredibly harsh environments, with no protection from radiation, little to no atmosphere, and extreme temperatures.
Living on those worlds is going to be hard, it’s going to be dangerous. Fortunately, there are a few pockets on those worlds that’ll make it a tiny little bit easier to get a foothold in the Solar System: lava tubes.
Those dark blobs in the photo are actually open skylights, the collapsed roofs of lava tubes on the Moon. They just look like dark areas because you can’t see the bottom. How cool is that?
And now, here are similar features on the surface of Mars. Here are several examples of cave skylights across the Red Planet.
And I want to show you a really special one. Check out this photo, where you can see the cave opening, how the Martian sand is flowing down into the skylight. You can even see it piling up on the cave floor. There’s no question, this is a cavern on Mars with opening to the surface.
Lava tubes are a common here on Earth, and you can find them wherever there’s been volcanic activity. During an eruption, lava gets flowing downhill through a channel. The surface cools and crusts over, but the lava keeps on flowing, like an underground river of molten rock.
In the right conditions, the lava can keep flowing, and empty out the channel completely, leaving behind a natural tunnel that can be dozens of kilometers long. The tubes can be wide, from a single meter to up to 15 meters wide. Definitely big enough to live inside.
Both the Moon and Mars had periods of volcanism. The biggest volcano in the Solar System, Olympus Mons on Mars, is an enormous shield volcano with endless lava fields surrounding it.
The SETI Institute recently announced that they had identified a series of small pits in a crater near the Moon’s northern pole. They found them by analyzing images taken by NASA’s Lunar Reconnaissance Orbiter.
They look like skylights, and match similar features on Mars, where there is no crater rim, and just a shadowed dark feature. Further evidence is that they lie along lunar sinuous rilles, those ancient lava rivers with collapses features in a row.
At this point, there have been about 200 of these features discovered on the Moon so far, and more discovered on Mars too.
In addition to the skylights discovered by spacecraft, planetary scientists have uncovered vast pit chains on Mars, which could be collapsed lava tubes. With the amount of volcanism that occured on Mars over billions of years, there should be many features worth exploring.
Because of the lower gravity on the Moon and Mars, lava tubes should be much more extreme. On Mars, there could be lava tubes that measure hundreds of meters across, and hundreds of kilometers long. On the Moon, lava tubes could be kilometers across. Big enough to hide a city inside.
Future Moon and Mars colonists will already be facing a life underground, to hide from the surface radiation, micrometeorite bombardment, extreme temperatures and to create a usable atmosphere. These natural tunnels will save them the hard work of needing to dig the tunnel.
The natural roofs on these caverns are thought to be 10 meters or more thick, with one site estimated to have a roof that’s 45-90 meters thick. This would be more than enough to protect against solar radiation and galactic cosmic radiation.
While the surface of the Moon varies in temperature from -180 C to +100 C, the interior of a lava tube would remain a constant chilly -20 C. This would be easy enough to keep warmed up, once it was sealed off and pressurized with a breathable atmosphere.
As we’ve mentioned time and time again, the lunar dust on the Moon is dangerous stuff, irritating eyes, nasal passages and lungs. Lunar colonists would want to minimize their exposure to it at all costs. By sealing off the interior of the lava tube, they could prevent further dust from getting in. In fact, the dust is also electrically charged, and could be a hazard to electronics.
In terms of resources, the Moon has plenty. There’s aluminum everywhere in the regolith, as well as iron and titanium. But the most valuable one for humans, water, could be down there too. In the eternally shadowed craters, there could be large deposits of water collected down below that colonists could harvest.
There’s another advantage, the lava tubes on Mars could be the best places to search for life on the Red Planet. The natural protection would also keep Martian bacteria less exposed to the harsh conditions of the surface.
Future explorers could be protected inside the lava tubes at the same time that they’re in the ideal place to search for life on Mars. That’s convenient.
Of course NASA and the European Space Agency have considered human and robotic missions that could travel to the Moon or Mars and explore the interiors of lava tubes.
In 2011, a group of researchers proposed a mission design for a combined lander-rover that would map out a skylight on the Moon in incredible detail. It’s known as the Marius Hills Hole, and measures about 65 meters across.
First, the lander would descend down to the surface of the Moon near the hole, using a pulsed laser called LIDAR to map out a 50-meter region around the landing site, looking for hazards.
The spacecraft would then choose a landing site and deploy a rover that would scan the region around the skylight in extreme detail, peeking down into the lava tube when the light is right.
Following that, would come the missions to actually explore down in the tunnels. Remember how big they are, potentially hundreds of meters and even kilometers across.
You can imagine various robotic rovers and landers, but one of my favorite ideas is a snake robot developed by SINTEF in Norway. The robot uses hydraulics to move segments of its body, allowing it to move like a real snake. It could climb stairs, navigate up and down slopes, go around corners, and be able to handle the unpredictable terrain of the floor of a lavatube.
After the robots come the humans. The tricky part is getting from the surface down to the tunnel floor. Mission planners have proposed traditional rappelling and even astronauts with jetpacks who would lower themselves down into the tunnel to explore around.
The first astronauts would descend down to the floor of the lava tube bringing quadruped pack mule robots that would be able to navigate the rough terrain of the tunnel floor. Once inside, they’d set up a communications link at the crater opening, and then deploy a pressurized tent as a temporary habitat.
The astronauts would be free to travel several kilometers into the lava tube, mapping the interior, and taking samples. They could set up their tent at different points, allowing a much deeper exploration.
Of course, then hostile cave aliens would pick them off one by one, and the only way we’d know about the mission is from a series of found footage and computer logs. But I digress.
The European Space Agency has been developing tools to measure the interior of caves here on Earth, to develop the technology that could be used to explore other worlds. You’re looking at a 3D image of the interior of a cave network in Spain.
A team of researchers, including a European astronaut, used backpack-based cameras and LIDAR instruments to map out the cave to a resolution of just a few centimeters. They also tested out handheld tools to examine the cave walls, doing the same kinds of experiments future astronauts might do.
The long term goal, of course, is to set up some kind of long term colony inside lava tubes on the Moon or Mars.
What started as a temporary hiding place from the brutal environment of the Moon and Mars would become the base of operations for a future habitat and eventually the beginnings of a scientific outpost or even a full colony.
There’s no question that lava tubes are going to be one of the top priorities when we return to the Moon, and when the first astronaut sets foot on Mars. And with all the new missions in the works, from both NASA, SpaceX, the Europeans and even the Chinese, it looks like those days aren’t too far off now.