The planet Mars is calling to us. At least, that is the impression one gets when examining all the planned and proposed missions to the Red Planet in the coming decade. With so many space agencies currently sending missions there to characterize its environment, atmosphere, and geological history, it seems likely that crewed missions are right around the corner. In fact, both NASA and China have made it clear that they intend to send missions to Mars by the early 2030s that will culminate in the creation of surface habitats.
To ensure astronaut health and safety, both in transit and on the surface of Mars, scientists are investigated several means of radiation protection. In a recent study, a team from the Blue Marble Space Institute of Science (BMSIS) studied how various materials could be used to fashion radiation-protective structures. This included materials brought from Earth and those that can be harvested directly from the Martian environment. This is in keeping with the In-Situ-Resource-Utilization (ISRU) process, where local resources are leveraged to meet the needs of the astronaut crews and the mission.
Ever since astronomers found that Earth and the Solar System are not unique in the cosmos, humanity has dreamed of the day when we might explore nearby stars and settle extrasolar planets. Unfortunately, the laws of physics impose strict limitations on how fast things can travel in our Universe, otherwise known as Einstein’s General Theory of Relativity. Per this theory, the speed of light is constant and absolute, and objects approaching it will experience an increase in their inertial mass (thereby requiring more mass to accelerate further).
While no object can ever reach or exceed the speed of light, there may be a loophole that allows for Faster-Than-Light (FTL) travel. It’s known as the Alcubierre Warp Metric, which describes a warp field that contracts spacetime in front of a spacecraft and expands it behind. This would allow the spacecraft to effectively travel faster than the speed of light while not violating Relativity or causality. For more than a decade, Dr. Harold “Sonny” White has been investigating this theory in the hopes of bringing it closer to reality.
Previously, Dr. White pursued the development of an Alcubierre Warp Drive with his colleagues at the Advanced Propulsion Physics Research Laboratory (NASA Eagleworks) at NASA’s Johnson Space Center. In 2020, he began working with engineers and scientists at the Limitless Space Institute, a non-profit organization dedicated to education, outreach, research grants, and the development of advanced propulsion methods – which they hope will culminate in the creation of the first warp drive!
It might be hard to fathom now, but the human exploration of the solar system isn’t going to stop at the Moon and Mars. Eventually, our descendants will spread throughout the solar system – for those interested in space exploration, the question is only of when rather than if. Answering that question is the focus of a new paper released on arXiv by a group of researchers from the US, China, and the Netherlands. Their approach is highly theoretical, but it is likely more accurate than previous estimates, and it gives a reasonable idea of when we could expect to see humans in the outer solar system. The latest they think we could reach the Saturnian system is 2153.
A team of researchers at the University of Illinois Urbana-Champaign have found a way for travelers through the Solar System to work out exactly where they are, without needing help from ground-based observers on Earth. They have refined the pulsar navigation technique, which uses X-ray signals from distant pulsars, in a way similar to how GPS uses signals from a constellation of specialized satellites, to calculate an exact position .
Since 2002, the United States National Research Council (NRC) has released a publication that identifies objectives and makes recommendations for science missions for NASA, the National Science Foundation, and other government agencies for the next decade. These reports, appropriately named Planetary Science Decadal Surveys, help inform future NASA missions that address the mysteries that persist in astronomy, astrophysics, earth science, and heliophysics.
On Thursday, April 19th, in a briefing in Washington D.C., the National Academies of Sciences, Engineering, and Medicine (NASEM) shared the main findings of the Planetary Science and Astrobiology Decadal Survey 2023-2032. The event was live-streamed and consisted of NASEM committee members discussing the key science questions, priority missions, and research strategies identified and recommended, followed by a Q&A session with the audience.
Between the exponential growth of the commercial space industry (aka. NewSpace) and missions planned for the Moon in this decade, it’s generally agreed that we are living in the “Space Age 2.0.” Even more ambitious are the proposals to send crewed missions to Mars in the next decade, which would see astronauts traveling beyond the Earth-Moon system for the first time. The challenge this represents has inspired many innovative new ideas for spacecraft, life-support systems, and propulsion.
In particular, missions planners and engineers are investigating Directed Energy (DE) propulsion, where laser arrays are used to accelerate light sails to relativistic speeds (a fraction of the speed of light). In a recent study, a team from UCLA explained how a fleet of tiny probes with light sails could be used to explore the Solar System. These probes would rely on a low-power laser array, thereby being more cost-effective than similar concepts but would be much faster than conventional rockets.
A renewed era of space exploration is upon us, and many exciting missions will be headed to space in the coming years. These include crewed missions to the Moon and the creation of permanent bases there. Beyond the Earth-Moon system, there are multiple proposals for crewed missions to Mars and beyond. This presents significant challenges since a one-way transit to Mars can take six to nine months. Even with new propulsion technologies like nuclear rockets, it could still take more than three months to get to Mars.
In addition to the physical and mental stresses imposed on the astronauts by the duration and long-term exposure to microgravity and radiation, there are also the logistical challenges these types of missions will impose (i.e., massive spacecraft, lots of supplies, and significant expense). Looking for alternatives, the European Space Agency (ESA) is investigating hibernation technology that would allow their astronauts to sleep for much of the voyage and arrive at Mars ready to explore.
In the 1960s, American physicist Robert W. Bussard proposed a radical idea for interstellar travel: a spacecraft that relied on powerful magnetic fields to harvest hydrogen directly from the interstellar medium. The high speed of this “ramjet” forces the hydrogen into a progressively constricted magnetic field until fusion occurs. The magnetic field then directs the resulting energy towards the rear of the spacecraft to generate propulsion.
As it’s come to be known, the Bussard Ramjet has since been popularized by hard science fiction writers like Poul Anderson, Larry Niven, Vernor Vinge, and science communicators like Carl Sagan. Unfortunately, a team of physicists recently analyzed the concept in more detail and concluded that Bussard’s idea is not practical. At a time when interstellar travel looks destined to become a real possibility, this analysis might seem like a wet blanket but is more of a reality check.
Even after 30 months in space, The Planetary Society’s LightSail 2 mission continues to successfully “sail on sunbeams” demonstrating solar sail technology in Earth orbit. The mission is providing hard data for future missions that hope to employ solar sails to explore the cosmos.