Potential contamination carried by space vehicles is a major concern to the public and private space industry. Satellites and space craft components are manufactured in clear rooms to prevent the possibility of biological contamination of astronomical bodies. However, recently a new type of contamination was discovered. SpaceX cargo flights to the International Space Station (ISS) are apparently contaminating the outside of Station with gases carried from Earth to orbit.
In early 2017, a SpaceX Falcon 9 rocket carried a Dragon capsule to rendezvous with the ISS. One of the pieces of equipment in the supply capsule was the SAGE III. This device was designed to measure ozone molecules and aerosols in the atmosphere of the Earth. SAGEs I and II had already documented the growth of holes in the Earths ozone layer and the shrinking of the holes after the elimination of the use of Freon.
SAGE III is extremely sensitive. One of the concerns with such sensitivity is that environmental contamination could affect its readings. To combat this, the device contains contamination sensors. Following the delivery of the SAGE III to the ISS and its installation, the subsequent arrivals of Dragon supply capsules triggered these contamination sensors. These Dragon capsules were outgassing something that was affecting the function of the SAGE III.
New pieces of equipment can outgas molecules that have migrated from the interior of the equipment to their surfaces. This can result in a greasy film forming in the neighborhood of the equipment. In the case of the ISS, molecules delivered by the Dragon capsules were adhering to the SAGE III.
This same problem was discovered when components of the Hubble Space Telescope were returned to Earth. The contamination outgassed from the body of the Hubble degraded the ability of the instruments to detect ultraviolet light which was critical to the Hubble mission.
While NASA has dealt with such contamination for decades, the situation with the Dragon capsules is new. NASA is outsourcing more and more work to private space companies. It is critical for the success of such joint ventures to work that NASA be able to depend on private space contractors to deal properly with their own sources of contamination.
Contamination detection on the SAGE III is carried out by eight “thermoelectric quartz crystal microbalances” that each contain two crystals. Each crystal oscillates at a frequency that is related to the mass of the sensor. If any of the crystals gain mass from such sources as the Dragon capsules, its frequency is altered.
When the SAGE III arrived at the ISS, each pair of crystals in the microbalances oscillated at exactly the same frequency. One of the two crystals is exposed to space and the other is protected by a container. If the exposed crystal gains mass, this changes its frequency, so the two crystals are no longer in synchronization. This results in a signal being generated that there is contamination in the environment. There are other highly sensitive sensors on the SAGE III that could be affected by contamination. Subsequent arrivals of Dragon capsules caused the microbalances to register up to seventy times the allowed level of contaminants.
At first it was suspected that solar panels on the Dragon capsules were outgassing but this was tested and eliminated as a contamination source. Now it is suspected that the body of the Dragon capsule is the source. Altogether, seven sensitive areas or instruments on the ISS may be in dangers from the contamination.
NASA and SpaceX are working on identifying the source of the outgassing from the Dragon capsules. One independent analyst believes that the source of the outgassing is the paint on the outside of the Dragon capsules. One family of paints used on spacecraft such as the Dragon capsules is known to breakdown and outgas if it is contaminated and then exposed to ultraviolet light which is plentily in space.
NASA is reluctant to share information on the problem and actions taken to prevent such outgassing in the future. Reporters questions have been gone unanswered and documents about the problem have been removed from public access. It would be better for all involved if NASA was more open about this problem.
Potential contamination carried by space vehicles is a major concern to the public and private space industry. Satellites and space craft components are manufactured in clear rooms to prevent the possibility of biological contamination of astronomical bodies. However, recently a new type of contamination was discovered. SpaceX cargo flights to the International Space Station (ISS) are apparently contaminating the outside of Station with gases carried from Earth to orbit.
There has been a lot of discussion in the media lately with respect to whether we should create a colony on the Moon first or send missions to explore and colonize Mars first. We have billionaires such as Elon Musk who are dedicated to getting human beings to Mars. National space programs have sent a lot of robot probes to Mars with a U.S. probe landing just a few days ago. However, recent announcements of space-faring nation suggest that the Moon will be getting a lot of attention that Mars in the near future.
Jim Bridenstine is the NASA Administrator. He says that the U.S. will have a continuous manned presence on the Moon within ten years. This lunar presence will help lay the groundwork for future missions to Mars. In a recent interview, he said, “Right now we’re building a space station, we call it ‘Gateway,’ that’s going to be in orbit around the moon — think of it as a reusable command module where we can have human presence in orbit around the moon. From there we want reusable landers that go back and forth to the surface of the moon. We think we can achieve this in about 10 years, the idea being prove the capability, retire the risk, prove the human physiology and then go on to Mars.”
In his interview with the Rising TV show, he revealed details of NASA’s plan to collaborate with nine U.S. commercial space firm to travel to the Moon. He said that he hopes that the creation of a commercial marketplace called the Commercial Lunar Payload Services Program (CLIPS) will help stimulate innovation in the exploration and exploitation of space. One of the goals of CLIPS is to develop technology that can be used to create the continuous presence on the Moon mentioned above.
Bridenstine also said in the interview, “At the end of the day, what we’re doing is we’re going to buy services where we’re going to have multiple companies competing on cost and innovation to deliver payloads to the surface of the moon — right now we’re just talking about scientific instruments, not large payloads, but building the capability that then feeds forward to larger landers that would include humans.”
U.S. President Donald Trump has issued the Space Policy Directive which calls for a manned return to the Moon. Bridenstine says that the importance of the Trump policy directive lies its support for building a sustainable and continuing presences on the Moon in the next ten years.
The Moon is much closer to the Earth than Mars. The Moon is always on the same side of the Sun as the Earth while the distance to Mars makes huge changes as the planets whirl about the Sun. The Earth and Mars are only aligned on the same side of the Sun every twenty-six months. This means that current planning for Mars missions will have to allow for astronauts to spend two years on Mars after they land before they can return to Earth.
Bridenstine says, “The moon represents a proving ground, it’s the way we can reduce risk, we can prove technology, we can prove human physiology, we can develop the capabilities to utilize the resources of the moon to survive on the surface of the moon and then we take all of those capabilities and we replicate them at Mars. This week we landed on the surface of Mars. It’s the eighth time in the history of humanity that anyone has landed on the surface of Mars softly with a mission that’s capable of carrying forward.”
NASA is considering selling seats on the launch vehicles that will be used to ferry passengers to the International Space Station (ISS). NASA would like to have additional sources of funding beyond that provided by the U.S. government for government missions.
Russia has already sent rich individuals into Earth orbit for millions of dollars per flight. There are several private companies which have expressed the intent to take tourists into space. NASA has only allowed a few civilian to ride the old Space Shuttles into space. One of those occasions ended in tragedy when a teacher named Christa McAuliffe was killed in the explosion of the Space Shuttle Challenger in 1986.
Two months ago, the NASA Administrator Jim Bridenstine announced that he was creating a NASA advisory council with the purpose of increasing visibility of NASA among the public by working with space companies in the private sector. He said that he wants NASA and its astronauts “embedded into the American culture.” He also said that “The reality is, we’re in a new era now.”
Michael Gold is the vice president of regulatory affairs and policy at Maxar Technologies and the head of the new NASA advisory council. He said, “Just like in the early days of aviation with barnstorming, these initial activities will help build the infrastructure and the foundation that can lead to future innovations that, frankly, we cannot imagine right now.”
The proposal to allow paid civilian space flights was put forth by a subcommittee of the new NASA advisory council. The proposal is in the early stages of development. Any such proposal will have to be approved by the whole NASA advisory council and then sent over to the NASA Administrator.
One of the things that has prompted NASA to consider revenue streams beyond government appropriations was the recent activity at the White House to end the direct funding of the ISS. The President would like to see the ISS become a commercial enterprise. This proposal has been met with stiff resistance from Congress. There are serious questions about how such commercialization could be realized and how it would be funded.
Selling seats on missions to the ISS would only bring in a few tens of millions of dollars at best. NASA hopes that such income could be used to help the agency “facilitate commercialization of space platforms in and beyond” low Earth orbit.
Currently NASA rules prohibit NASA from endorsing particular products or services. Another proposal from the advisory council subcommittee released Friday included the idea of commercializing the NASA logo. Today NASA does not put their logo on the private rockets that ferry cargo to the ISS or launch satellites because they are afraid that this use of their logo would appear as an implicit endorsement of the space companies that supply launch services to NASA. They might also allow astronauts to appear in television commercials to promote NASA’s “brand.” Another idea would be to sell naming rights for NASA launch vehicles.
The NASA Administrator said Friday that it would be a “heavy lift” to achieve such goals. The subcommittee approved language recommending “space-based promotional activities” that “could enhance NASA’s public profile and encourage youth to pursue careers in science, technology, engineering and mathematics.”
Until recently, the Chinese space program was government run. China opened up its space exploration and exploitation to private companies in 2014. In the last few years, private companies have entered the arena in China and are pushing hard to catch up to the private space industry that is thriving in the United States. Now there are eighty commercial Chinese space-technology startups. China is hoping to snag a piece of the three hundred and fifty-billion dollar global commercial space marketplace.
Most of the eighty Chinese companies are constructing satellites and related software applications. There are ten Chinese companies who are more ambitious. They are working on the development of launch vehicles and hoping to compete with companies such as SpaceX in the U.S. for the growing global market for the launch of satellites.
Landscape Technology Corporation (LTC) was started in 2015 by Roger Zhang, a former banker with ties to major Chinese banks. He recruited a group of experienced engineers who had worked on the Long March family of rockets that are the foundation of the Chinese government space program. LTC has raised about seventy-two million dollars from private investors and city governments.
Landscape Technology Corporation had hoped to become the first Chinese company to launch a rocket into Earth orbit last month. However, its Vermillion Bird rocket was unable to successfully carry a satellite to orbit.
Zhang said that LTC needs another one hundred and fifteen million dollars of capital in order to actually start commercial operations. The LTC rocket that failed its first mission could only carry a six-hundred and sixty pound satellite to orbit. LTC is currently working on a larger and more complex launch vehicle that will be able to carry an eight thousand and eight-hundred pound satellite to orbit. This rocket will be a serious contender with SpaceX which can carry a ten-thousand pound payload into orbit.
SpaceX charges about sixty-two million dollars to launch a payload with its Falcon 9 rocket. Zhang says that the new LTC rocket will be able to carry out a launch for about fifteen million dollars. While this is considerably cheaper than the Falcon 9, the LTC rocket can only reach lower Earth orbits than the Falcon 9.
One Space, a major rival of LTC, was started with one hundred and sixteen million dollars of capital from private investors and state-owned funds. Now One Space has the opportunity to be the first private rocket to carry a satellite into orbit in late 2018. If they fail, there are more private Chinese space companies lining up for launches in 2019.
Many of the new Chinese private space companies are working on CubeSats. These are very small satellites that are based on a unit size cube about four inches on a side. These satellites are relatively cheap to build and can be launched twenty at a time in a single launch vehicle. They can be distributed in large sets to provide wide coverage for communication and GPS applications.
Beijing-based ZeroG Labs is a private Chinese space company that builds and sells CubeSats. They are able to sell a single CubeSat for about one hundred thousand dollars which is very cheap when compared to full sized satellites. Zhang Bei is the founder of ZeroG Labs. He has a background in information technology. ZeroG Labs raised about three million dollars in its first round of investment. It already has three CubeSats in Earth orbit with plans to launch one hundred and thirty-two more CubeSats by 2022. CubeSats can provide remote sensing and Earth observation services for big companies. CubeSats will open up many new opportunities for Chinese space companies.
While the Chinese started late in private commercial space companies. They are working hard to catch up with a lot of assistance from the Chinese government.
There are many threats to human existence on Earth. There are inactive super volcanoes that could erupt and kill billions of people. Climate change is not as dramatic but does pose an existential threat. Comets or asteroids impacts could devastate the surface of the planet and wipe out the entire ecosystem. The human race could start a nuclear war that would result in the death of billions and the end of human civilization. A natural or artificial plague could sweep across the Earth, wiping out a large percent of the human population. The continued existence of human civilization with billions of people is not guaranteed.
SpaceLife Orgin is a biotech startup located in San Francisco, California. They are working to enable human reproduction in space as an insurance policy in the face of all these existential dangers to human life on Earth. They have three missions planned for the next few years.
The first mission of SpaceLife is called “Mission Arc.” They intend to launch the mission in 2020. The core of the mission is one thousand protected tubes containing human reproductive cells in special radiation proof Ark containers. The cells, male sperm and female eggs, will be harvested in approved and supervised IVF clinics around the world. The cells will be vitrified by cooling them with cryopreservative chemicals to prevent the formation of ice crystals. The Arks are then stored in secure locations around the globe and in Earth orbit.
The second mission of SpaceLife is called “Mission Lotus”. It is being planned for launch in 2021. SpaceLife is developing a new proprietary technology they refer to as a “Space-Embryo-Incubator”. These incubators will be sent into space with human sperm and eggs. After they have been launched into space, the sperm and eggs will be combined to start the formation of embryos. After four days of development, the embryos will be returned to Earth and checked. Those embryos that are developing normally will be implanted in their mothers for normal pregnancies.
The third SpaceLife mission is called “Mission Cradle”. It is scheduled for launch in 2024 providing that the previous two missions are successful. The purpose of this mission is for a pregnant woman to give birth in space. During a twenty-four to thirty-six hour mission, a child will be born two hundred and fifty miles above the Earth. A trained team of medical experts will be on the mission to support the delivery. The risks to the mother and child will be reduced as much as possible.
While the desire to take steps to prevent the extinction of human life of Earth is a noble one, there are a number of issues that could cause problems for the SpaceLife Missions. There is a great deal of dangerous radiation in space that can cause biological damage. Zero gravity has negative influences on human health. Disease causing bacteria become more virulent in space. Being launched into space is very stressful on a human body. There will be danger to a pregnant woman enduring such stress beyond the usual stress to an astronaut. Returning from orbit is also stressful and it might pose threat to the mother and/or newly born baby. It will be interesting to see what happens during these SpaceLife Missions if they are, in fact, carried out.
I have blogged before about the effects of space travel on human health. There are a variety of negative effects on different organs in the human body caused by either zero gravity or space radiation. Today I am going to report on a study of the brains of Russian cosmonauts following their time spent in orbit around the Earth.
Floris Wuyts is a neuroscientist at the University of Antwerp. He led a team that has just published an article in The New England Journal of Medicine. The brains of ten Russian cosmonauts were scanned using a magnetic resonance imaging prior to their being sent to the International Space Station. Nine days after their return, they were scanned again. All of the cosmonauts are male with a mean age of forty-four. The average time spent in the ISS was one hundred and seventy-nine days. Seven of the ten also had their brains scanned about two hundred days after their flight to investigate their recovery from time in space.
The gray matter in the brain consists of neuronal cell bodies, neuropil (dendrites and myelinated as well as unmyelinated axons), glial cells (astrocytes and oligodendrocytes), synapses, and capillaries. What the researchers found was that there was a reduction of up to three and three tenths of a percent in gray matter during the time the cosmonauts spent at the ISS. The follow up scan after two hundred days found that while gray matter had rebounded, it had still not returned to the level found in the preflight scans.
White matter in the brain consists of bundles of nerve fibers sheathed in myelin. The myelin sheaths increase the speed of transmissions between different parts of the brain. It turns out that the volume of white matter in the brain did not changes while the cosmonauts were in orbit. However, after the two hundred day waiting period, the brain scans revealed that white matter had decreased after the cosmonauts returned from orbit. The research team believe that long term changes in cerebrospinal fluid following return to Earth might be involved but more research is needed to verify that.
The cerebrospinal fluid that bathes the brain was found to have increased during the time that the cosmonauts spent in orbit. The primary focus of this research was to track changes in the volumes of brain tissue. No work was done to find out if these changes had an effect on the cognitive abilities or the behavior of the cosmonauts.
Angelique Van Ombergen is a postdoctoral researcher at the University of Antwerp. She said that it was not clear why the lack of gravity in orbit caused these specific changes to the volume of brain tissue. The best current theory suggests that without gravity pulling fluids down in the body, the fluids move up into the torso and head of the astronaut while in orbit. She said in an email that, “We believe all the changes we see here are due to this fluid shift.”
Van Ombergen also said, “The neat thing about MRI brain scans is that they allow multiple aspects of the brain to be investigated. The current study is only approaching one aspect (the tissue volumes), but we can also study white matter tracts more in detail, as well as brain connectivity.”
More astronauts are being recruited by the research team. Possible effects on cognitive ability from prolonged space flight will be studied next. Van Ombergen said, “A priority, in my opinion, is that future studies should also be set up to look at how these brain changes translate to the clinical performance of astronauts,” she explained. “For example: does it impact their cognition? How exactly can these brain changes be related to visual changes in space travelers? Such questions are necessary in order to better understand what’s going on and to prepare astronauts better for future missions.”
A solar mirror is an object with a reflective surface that is used to reflect the light of the Sun. Solar mirrors have many uses such as concentrating solar radiation for heating or the generation of electricity. When placed in orbit around the Earth, solar mirrors are referred to as Space Reflectors (SR) and could provide illumination at night for a specific area.
In 1992, Russia began a series of experiments on SRs made from solar sails with the intention of providing illumination for far northern cities that receive much less sunlight in the winter months. None of the experiments were successful in illuminating the Earth’s surface and the Russians gave up in 1999.
Last January, Rocket Lab, a private U.S. space company launched a reflective mini-satellite into orbit around the Earth to create an artificial star which they called Humanity Star. It is a sphere about three feet in diameter and has a surface with seventy-six reflective panels. It was launched into a polar orbit and circled the Earth once every ninety-two minutes. The orbital distance varied between one hundred and eighty and three hundred and twenty miles.
The satellite was intended to orbit for nine months but it burned up on reentry after orbiting for only a couple of months. Humanity Star was bright enough to be seen by the naked eye from the surface of the Earth. The website for Humanity Star says, “the Humanity Star was designed to be a bright symbol and reminder to all on Earth about our fragile place in the universe.”
Astronomers were critical of the Rocket Lab project. They complained that reflective objects in orbit can interfere with astronomical observations. Supporters of the project pointed out that flares of light from the International Space Station and other satellites are much brighter than the light from Humanity Star.
China has just announced plans to send an ‘artificial moon’ into Earth orbit in 2020 to provide night time illumination in urban areas. Their first SR will orbit above the city of Chengdu which is the capital of the Sichuan province. If the first SR is successful, then another three will be launched by 2022.
Chinese scientists estimate that the SR will about eight times as luminous as the actual moon when it is full. It will only orbit at around three hundred and ten miles above the Earth. The actual light provided for city streets will only be about one fifth of the illumination currently provided by street lights.
It is estimated that the SR could save the city about one hundred and seventy-three million dollars by reducing the cost of electricity currently used for street lights. It could also help first responders to natural disasters when the power grid goes down and there are no street lights.
Wu Chunfeng, chief of the Tian Fu New Area Science Society, has been interviewed
about the plan. He called for more testing to be sure that the plan is viable and that such artificial illumination will not cause problems for the natural environment. He also said, “We will only conduct our tests in an uninhabited desert, so our light beams will not interfere with any people or Earth-based space observation equipment.”
Part 5 of 5 Parts (Please read Parts 1, 2, 3 and 4)
Cáceres discussed an estimation of the development and construction cost of the first BFR. He said, “If I had to venture to guess, I would say it would be somewhere in the $4 billion to $5 billion range.” He said that if there are severe problems and setbacks, the cost could be much higher than that. He added that, “That's why so many government space programs tend to be so expensive — because they just go on and on, forever and ever, for technical reasons as well as budgetary and political reasons.”
Cáceres suggested that if SpaceX gets far enough in the development process for the BFR to be taken seriously, NASA might be interested enough to provide some assistance and funding. He said, “Ultimately, BFR could become a joint US government-SpaceX program. That would be my guess, eventually, because as much as I admire the success of SpaceX, this just seems like something too massive and too complicated for one company alone to handle.”
SpaceX has an upcoming mission to send astronauts to the International Space Station. If SpaceX can successfully carry out this mission with its Falcon 9 or Falcon heavy launch vehicle, this will improve the odds that they can move forward successfully with the BFR program. Repeated SpaceX missions to the ISS will add increasing confidence in the space industry that SpaceX is capable of advanced missions such as the BFR.
SpaceX has announced that the first mission for the BFR will be to take a space tourist around the Moon. If this mission is successful, it will be huge public relations coup. NASA and Congress cannot help but be impressed and motivated to invest in the program.
Beyond the Lunar tourist mission, Musk intends to use the BFR to explore and colonize Mars. He said, “The first journey to Mars is going to be really very dangerous. The risk of fatality will be high; there's just no way around it. It would be basically: Are you prepared to die? And if that's OK, then you're a candidate for going."
Cáceres response to Musk’s statement was, “I immediately thought: That's not something that any representative, any CEO from a company, or any NASA administrator would say. That's about as blunt as you can be, and I think he was being very truthful.”
Chris Hadfield is a retired astronaut. He pointed out that other periods of exploration were quite deadly as sailors explored the oceans of Earth on voyages that lasted for years. He said, “The majority of the astronauts that we send on those missions to Mars won't make it.” Still, astronauts will probably be ready to attempt to travel to Mars because there have already been volunteers for the first private Moon landings.
Cáceres continued, “If we want to actually open space to average people rather than government astronauts, then we've got to accept that there's going to be a lot of fatalities. We can either decide that that's acceptable or it's not, in which case we don't explore space any more than we have already. SpaceX is going to fail in the future — rockets are going to explode, and people are going to die is what everyone has to totally understand.”
Part 4 of 5 Parts (Please read Parts 1, 2 and 3)
Steve Nutt said, “There are so many different parts of this thing, the complexity is daunting. There will have to be a variety of materials and joining methods to accomplish everything this has to accomplish. When a metal part gets damaged, there's usually a dent or a scratch or something like that. With composite parts, there can be damage and no manifestations at the surface. It's all subsurface.”
All of the carbon fiber sections will have to be carefully checked for flaws in every square inch with ultrasound scanners. Cáceres said, “You may have some structural problems on an aircraft, but the aircraft won't explode," Cáceres said. "But on a rocket, leaks, cracks, and instability — those things can be catastrophic. It explodes and people die. When you're building something this big, the only real way to test it is once you've completed it, and you launch it. You better have a lot of money, because you're probably going to go through a lot of big, big structures before you get the one that works.”
SpaceX has suffered serious accidents and failures with its current fleet of rockets. Musk will certain run extensive tests and checks on components and, ultimately, on the full prototype of the BRF before any missions are flown. Nutt said, with respect to going to Mars, “It's such a long mission. I think the chances of some kind of damage or failure en route are much greater than a mission of days or weeks that we've seen in our lifetime.”
Tiny pieces of rocks or comet dust in deep space can be very dangerous to a spacecraft because they are traveling at thousands of miles per hour. One strike by a tiny object could cripple and end a deep-space mission if it does not have the ability to carry out repairs during the mission. Nutt said, “Those things can go right through any kind of structure and do a lot of damage.”
It is very hard to repair carbon fiber composites even on Earth. Some jet fights employ carbon fiber composites. If there is a hole in a section of the fuselage, workers sand and polish the damaged area, use trowels to lay down layers of fresh epoxy, put the damaged section in a vacuum chamber and subject it to heat.
Nutt said, “Things that you might be able to repair with some difficulty on Earth are orders of magnitude more difficult to execute and accomplish in space. It's a big structure with a lot of components. The chances of failure are not zero. So you have to worry about those things and have contingency plans for all of them.”
Cáceres said that each launch of the BFR may costs around ten million dollars with most of the cost being for fuel because each BFR will be used many times. SpaceX’s Falcon Heavy launch vehicle costs about one hundred million dollars for each launch. Each Falcon Heavy can only lift half the weight that can be sent into space by the BFR.
Please read Part 5
Part 3 of 5 Parts (Please read Parts 1 and 2)
The creation of a huge carbon fiber structure faces a number of serious technical challenges. The epoxy used to create carbon fiber composites cures at room temperature. Each different kind of epoxy has its own rate of curing. The type of epoxy that is most often used in manufacture of airplane sections will only last for about four weeks before it has cured too much to be applied. That means that sections of the BFR will have to be built within about a month.
Carbon fiber composites can be damaged by coming into contact with super cooled liquids such as the liquid methane and liquid oxygen that will be used to fuel the BFR. In 2016, a SpaceX rocket was destroyed on the launch pad because a carbon-fiber-wrapped tank filled with super-cooled liquids exploded. Musk said that the tank failed due to cracking and leaking. Last year, Musk said that SpaceX had created a stronger tank that could handle the very low temperatures of the fuels.
In order to test their new tank, SpaceX built the biggest carbon-fiber-composite fuel tank ever constructed. They put it on a barge, towed it out to sea, filled it with super-cooled liquids and increased the pressure in the tank until it exploded.
Another big potential problem is the fact that if the epoxy does not cure properly and completely, there could be flaws that would be very hard to detect that could bring missions to a disastrous end. In order to prevent this, carbon fiber composites have to be squeezed under very high pressure to collapse voids, push out bubbles and ensure strong bonds.
Autry said, “That's typically done with a giant pressurized oven, like a pressure cooker, that's called an autoclave. But these things are very expensive.” Marco Cáceres is a senior space analyst at the Teal Group. He said that it cost Boeing almost three hundred million dollars to build a huge autoclave for pressure treating sections for the 787.
An autoclave big enough to cure sections for the BFR would cost much more than the Boeing autoclave. He suspects that SpaceX may try a different approach to curing sections of the BFR. He says that SpaceX could make an oven to cure the BFR sections. This could be as low as one tenth the cost of an autoclave. SpaceX could put each cured section of the BRF in a giant plastic bag, draw all the air out to squish the carbon-fiber-layers together and then heat the bag in a giant oven.
Following the curing and pressure heating of the sections of the BFR, the mandrels would be taken apart and removed from the sections of the BRF and then the several sections would be fused in some way to create a single fuselage. Boeing used fifty thousand metal fasteners to connect the segments of the fuselage for the 787. Many of the fasteners had to be replaced and several of the first planes produced failed pressurization tests. These problems would be much worse for a spacecraft. Temperature differences encountered by different components of a spacecraft can be hundreds of degrees. Different materials used in the construction of spacecraft expand and shrink at different rates under temperatures changes.
Please read Part 4
Part 2 of 5 Parts (Please read Part 1 first)
SpaceX says that when all the components and tests have been completed, the rocket will carry the spacecraft above the Earth and then detach itself to fly back to Earth for inspection and refueling. The spacecraft will fire its engines and achieve Earth orbit. The president of SpaceX says that this might happen as early as 2020.
It will take most of the liquid methane and liquid oxygen fuel in the spacecraft section to get to Earth orbit. SpaceX says that following the entry into Earth orbit, SpaceX will launch tanker spacecraft which will rendezvous with the first spacecraft. It may take as many as a dozen refueling flights and rendezvous’ to fill the tanks of the spacecraft. One of SpaceX’s Mars development engineers has said, “We go from getting 100 tons or more into low-Earth orbit, then refill, and we can take that payload pretty much anywhere — including the surface of Mars.”
If the proper infrastructure on Mars is available, liquid methane and liquid oxygen can be manufactured and used to refuel the spacecraft that are sent to Mars by using water in Martian soil, carbon dioxide in the Martian atmosphere and electricity from the solar panels.
Musk’s plan calls for the entire spacecraft to be constructed from advanced carbon fiber Composites. Composites of carbon fiber contain huge quantities tiny but extremely strong threads made of carbon. These threads are often woven into a fabric which is then embedded in a glue-like epoxy. Once cured in an oven, the epoxy hardens into an extremely strong resin surrounding and penetrating the carbon fiber fabrics. Carbon fiber structures require only one fifth of the material need for steel structures and many types are even stronger than steel. Carbon threads are also able to be made into materials that have similar properties to aluminum but are only half of the mass of aluminum. Together you wind up with a material stronger that steel and lighter than aluminum.
Musk is convinced that the BFR will require such a construction material to live up to expectations. However, building huge structures such as the BFR with carbon fiber can be very difficult. Nothing like the BFR has ever been constructed. The Boeing 787 Dreamliner is about fifty percent composites by weight.
Musk has shown pictures of a metal cylinder about thirty feet in diameter which he said was a tool that will be used to construct the BFR. Analysts think that the cylinder is something called a “mandrel” which is used to apply carbon fiber materials. No one has ever built a mandrel as big as the object showing in Musk’s pictures. As a mandrel rotates, a robot moves along wrapping rolls of carbon-fiber tape around the cylinder.
Greg Autry is the director of the Southern California Spaceflight Initiative and an expert on the space industry. He told a reporter that “You lay layer upon layer of the material. If you're going to make a spacecraft part, you'd probably have dozens of layers of material on top of each other.”
Please read Part 3
Part 1 of 5 Parts
Elon Musk has been in the news a lot lately for a variety of reasons. A lot of the stories have to do with his obsession to send astronauts to Mars. His company, SpaceX, is working on a new rocket dubbed that Big Falcon Rocket (BFR) which will figure in his plans for Mars missions.
A full-scale prototype of the BFR is being developed in a huge white tent located at the Port of Los Angeles. The BFR will consist of a one hundred and fifty-seven-foot-long spacecraft on top of a one hundred a ninety-one tall rocket booster. This is equivalent to the height of a thirty-five-story building. When it is fully fueled, it will weigh almost nine million pounds. The specifications say that it can carry one hundred and fifty tons of cargo to Mars along with a hundred passengers. And, Musk claims that the entire system will be reusable.
Analysts say that this is the most ambitious space project ever attempted. They say that it is at least an order of magnitude beyond the lunar missions. Steve Nutt, a professor of chemical, aerospace and mechanical engineering at the University of Southern California, said, “It sounds like science fiction.” MusK is keeping the BFR program secret and no one has revealed any details. SpaceX has refused repeated requests for interviews or on-the-record comments about the project. The big question is how SpaceX can possibly build the giant spaceship on the schedule they have provided for completing the project.
With no information forth coming about the project from SpaceX it has been left to reporters to question experts in related disciplines to try to develop an understanding of the problems that the project must solve including potential building materials, advanced assembly processes. safety inspections and projected costs. Some commentators say that the most important question of all has nothing to do with the technical details. That question is whether or not the global community will be able to deal with probable disasters and fatalities related to some of SpaceX eventual Mars missions.
Musk has said that eventually, the BFR is intended to replace all of the current models of rockets and spacecraft currently in use by SpaceX. SpaceX has recently raised hundreds of millions of dollars, much of which will probably go to the development and construction of the BFR. SpaceX has recently been talking about sending a space tourist around the Moon. The research and development for this project will most likely assist the development of the BFR. SpaceX has six thousand employees and more and more of them are getting assigned to the BFR project.
Musk intends to complete development of the BFR sometime in 2019. The project in Los Angeles began last December so the schedule calls for the completion of the prototype BFR in from twelve and twenty-four months. For comparison, the NASA space shuttle orbiters each took about five years to complete.
Following its completion, the prototype BFR will probably be carried through the Panama Canal to a port in Texas and taken by truck to the SpaceX facility in Southern Texas. Once there, the BFR will be subjected to a series of tests. At the same time as this is playing itself out, SpaceX will be working to complete the permanent BFR factory being built at the Port of Los Angeles. The facility will cover about two hundred thousand square feet.
Please read Part 2
Last week I blogged about the history of the idea of a space elevator that could reach all the way beyond an anchor in geosynchronous orbit. Cargo and people could be moved to and from orbit in elevator cars traversing the elevator. Today I am going to talk about current work and future plans for such a construction.
A major international study was carried out and a report issued in 2012 concluded that it would be possible to build such a space elevator but the best results would require international co-operation. Many Japanese universities have been working to solve technical problems for such a project. A group at Kanagawa University is developing designs for the robotic cars that will climb the elevator.
Professor Tadash Egami at Kanagawa University said, "We're studying what mechanisms are needed in order to ascend at differing altitudes and the best brake system. “I don't think one company can make it, we'll need an international organization to make this big project.”
Obayashi is one of five giant Japanese construction firms. It has its headquarters in Minato, Tokyo but was established in 1892 in Osaka. It operates all over the world. One of its projects was the Tokyo Skytree which is a broadcasting, restaurant and observation tower in Sumida, Tokyo. It is the tallest tower in the world at a little more than two thousand feet.
Obayashi has announced plans to build a sixty-thousand-mile high space elevator. Robotic cars will use magnetic linear motors to carry cargo and people to a new space station at fraction of the current cost of chemical launch vehicles. Using current technology, it costs about ten thousand dollars a pound to send a payload into Earth orbit. Estimated cost of sending that same pound to orbit via space elevator is about a hundred dollars. They estimate that the trip will take seven days to reach from Earth to the space station.
The elevator will be constructed from carbon nanofibers. A R&D manager at Obayashi said, "The tensile strength is almost a hundred times stronger than steel cable so it's possible," Mr Yoji Ishikawa, a research and development manager at Obayashi, said, “Right now we can't make the cable long enough. We can only make 3-centimetre-long nanotubes but we need much more... we think by 2030 we'll be able to do it."
The space station reached by the elevator could be host to small rockets that could carry out orbital missions without the need for huge amounts of fuel to boost such rockets from the ground to Earth orbit.
Solar power satellites have been discussed for decades as a source of inexpensive, pollution free power. With the advent of a space elevator, the cost to construct such solar power stations would plummet.
Space tourism has also been discussed for decades. Obayashi is designing robot cars for elevators that can carry as many as thirty people. Personally, I don’t think that it will be a major industry even with a space elevator.
A space elevator is a fantastic idea which just might be possible. It would make exploration and exploitation of space much cheaper and easier. However, beyond the technical problems, there are many political, economic, and security issues that will have to be solved in order for it to become a reality.
When I was a little kid long ago, I read a comic book where a man in a spacesuit climbed a ladder all the way to space. It turns out that an elevator to space was first written of in 1895 by the Russian scientist, Konstantin Tsiolkovsky. In 1979 two different novels were published by well-known science fiction authors that featured the construction of the first space elevator. The novels shared some similarities but were just a case of an idea whose time had come.
The basic idea of a space elevator is to have a tower that reaches all the way from some spot on the equator to some sort of massive anchor like an asteroid in geosynchronous orbit and beyond. This would make moving materials and people up to orbit and down to Earth much, much cheaper than the current system of launching such payloads by chemical rockets as is currently the practice. There are many technical problems that would have to be overcome before such a space elevator would even be theoretically possible.
As the private space industry ramped up in the past couple of decades, there was a surge of interest in what were called tethers. These would be strong cables that could be used for many purposes in space and also serve as possible path forward toward space elevators. Tethers could be used to deorbit satellites when they reached the end of their life. Long strong tethers could rotate above the surface of the Earth and be used to raise and lower cargo to and from orbit. There were even designs for tethers that could be used to raise a spacecraft from Earth orbit to escape velocity for missions in deep space. Tethers Unlimited is a space industry startup that was founded in 1994 to explore tether technology. Unfortunately, interest in tethers waned and TU has had to develop and sell other space technology in order to survive.
One of the first things needed for an actual space elevator would be an incredibly strong material that would be able to handle the enormous stresses that would have to be endured by such a structure. The discovery and development of carbon nanotubes may be the basis of materials strong enough to create space elevators.
Another problem that has to be addressed is the problem of moving an asteroid into geosynchronous orbit to serve as an anchor. A space industry startup called Made in Space has sent a 3D printer to the International Space Station for testing. This company has published plans for sending a probe with a 3D printer to rendezvous with an asteroid. Once there, the plan is for the probe to deploy the printer and use asteroid materials to build a mass driver and a navigation system that would permit the asteroid to fly itself to a convenient location such as a Lagrange point in the Earth-Moon system or a geosynchronous orbit above the Earth.
Now that some realistic technologies are being develop that could lead to a space elevator, space industry companies and universities in Japan have committed to developing a space elevator. Some of these efforts will be explored in my next post.
NASA has split a sixty-five million dollars grant among six contractors to build a prototype space habitat by the end of this year. The contractors include Lockheed Martin, Boeing, Sierra Nevada Corporation’s Space Systems, Orbital ATK, Nanoracks and Bigelow Aerospace. NASA will evaluate each of the prototypes and proposals in order to better understand the systems and interfaces that are required to facilitate living in space for extended periods of time.
Lockheed is using the Donatello Multi-Purpose Logistics Module for their prototype. Originally the Donatello was constructed the purpose of conveying cargo to the International Space Station, but it was never put into service. Lockheed has refurbished a Donatello module for their entry into the NASA competition.
The Donatello is about fifteen feet wide and over twenty two feet long. It is about the size of a small bus. There are racks for equipment, life support systems, sleeping stations, exercise machines and workstation used to control robots. It will be close quarters for four astronauts to spend a month or two in the module.
Bill Pratt, the Lockheed program manager, said “You think of it as an RV in deep space. When you're in an RV, your table becomes your bed and things are always moving around, so you have to be really efficient with the space. That's a lot of what we are testing here. We want to get to the moon and to Mars as quickly as possible, and we feel like we actually have a lot of stuff that we can use to do that.”
The Lockheed team is using augmented reality headsets to help them visualize what the interior of the module will look like with all the equipment and furnishings installed.
NASA is working on the development of a habitation module for long missions to take astronauts to the Moon and Mars. The module that is selected in the competition will be attached to the Deep Space Gateway (DSG) that is being developed to orbit the Moon and serve as a way station for deep space missions.
The DSG will be much smaller than the International Space Station which weighs in at four hundred and fifty tons. The DSG will only weight about seventy-five tons and will include a habitat module, an air lock, a propulsion module, a docking port and a power bus.
NASA is collaborating with private contractors on the Space Launch System which includes the construction of the Orion spacecraft which will be the most powerful rocked ever built. The habitat and other modules will be attached to and launched by the Orion. They hope to test an unmanned Orion in a mission to orbit the Moon by 2020. If all goes as planned, there will be an manned Orion mission to the Moon in 2022.
The Orion rocket has been under development since 2004. One reason for the long development effort is related to the fact that it has to be a deep space craft able to handle the stress of a thousand-day mission to Mars. The Apollo mission allowed a small number of weld defects per inch. The Orion rocket specifications call for no weld defects at all.
The general manager of Lockheed Martin’s space division said, “This is the infrastructure for sustained human space exploration and so you have to account for every scenario that could come up, that's why the requirements are so stringent.”
Next month, the European Space Agency will deliver the European Service Module which will be installed below the habitat module on the Orion.