Sending an object to another star is still the stuff of science fiction. But some concrete missions could get us at least part way there. These “interstellar precursor missions” include a trip to the solar gravitational lens point at 550 AU from the sun—farther than any artificial object has ever been, including Voyager.
To get there, we’ll need plenty of new technologies, and a recent paper presented at the 75th International Astronautical Congress in Milan this month looks at one of those potential technologies—electric propulsion systems, otherwise known as ion drives.
The paper aimed to assess when any existing ion drive technology could port a large payload on one of several trajectories, including a trip around Jupiter, one visiting Pluto, and even one reaching that fabled solar gravitational lens. To do so, they specified an “ideal” ion drive with characteristics that enabled optimal values for some of the system’s physical characteristics.
First among those characteristics is the power plant. Ion thrusters need a power source and an effective one if they will last more than a decade under thrust. The paper defined an ideal power plan that can output 1 kW per kg of weight.
This is currently well outside the realm of possibility, with the best ion thruster power sources coming at something like 10 W per kg and even nuclear electric propulsion systems outputting 100 W per kg. Some potentially better technologies are on the horizon, but nothing tested in the literature would meet this requirement yet.
Fraser discusses the concept of the solar gravitational lens with Dr. Slava Turyshev
Thrust efficiency is another consideration for this idealized mission. The authors, who are writing under the banner of the Initiative for Interstellar Studies, a non-profit group based out of the U.K., suggested that an idealized thrust efficiency is 97%. That would also significantly improve existing technologies, which average closer to 75%–80% efficiency for working models.
Additional improvements could increase this number, such as magnetic containment fields around the thruster’s walls. Still, as it gets closer to that 97% range, finding efficiency improvements becomes harder and harder.
The last characteristic the authors considered was the specific impulse. This one has the most comprehensive variability regarding the theoretical potential of all three systems. Their idealized value of 34,000–76,000 seconds of specific impulse is well within the bounds of the potential values for more speculative technologies.
The paper mentions that specific impulse values twice the suggested upper range could be possible with the proper selection of thruster and propellant. They also point out that development on these technologies is stalled not because we can’t make drives with better specific impulse but because we can’t produce power plants that support them yet. So, solving the power plant issue will enable further development in this area.
Fraser discusses the details of ion engines and why they’re so efficient.
Suppose all three characteristics were combined into a complete functional propulsion system. In that case, the authors calculate that it could deliver a payload of almost 18,000 kg to the solar gravitational lens in just 13 years—much faster than any previous mission would be capable of.
But that optimization is still a long way off, and while there are missions planned for deployment to the SGL someday, it is still a long way off before they launch and even longer before they arrive there. In the meantime, engineers have some additional problems to solve if they want to optimize the potential of ion thrusters.
“Our new biochip device is low-cost — just a few dollars — and sensitive, which will make accurate disease diagnosis accessible to anyone, whether rich or poor,” said XiuJun (James) Li, Ph.D., a UTEP professor of chemistry and biochemistry. “It is portable, rapid and eliminates the need for specialized instruments.”
Li is the lead author on a new study describing the device; it’s published in Lab on a Chip, a journal that focuses on micro-scale and nanoscale devices.
Li explained that the most commonly used commercial method of cancer biomarker detection, known as ELISA, requires costly instrumentation to work correctly and can take twelve hours or longer to process a sample. This delay is heightened in rural areas in the U.S. or developing countries, he said, because patient samples must be transported to larger cities with specialized instruments, contributing to a higher rate of cancer mortality.
“If you can detect biomarkers early on, before the cancer spreads, you increase a patients’ chance of survival,” Li said. “Any delays in testing, especially in regions that don’t have access to expensive tools and instruments, can be very bad for a patient’s prognosis.”
The device that Li’s team created is microfluidic, which means that it can perform multiple functions using very small amounts of fluids. The device uses an innovative ‘paper-in-polymer-pond’ structure in which patient blood samples are introduced into tiny wells and onto a special kind of paper. The paper captures cancer protein biomarkers within the blood samples in just a few minutes. The paper subsequently changes color, and the intensity of the color indicates what type of cancer is detected and how far it has progressed.
So far, the research has focused on prostate and colorectal cancers, but Li said the method they devised could be applicable to a wide variety of cancer types.
Li said that the device can analyze a sample in an hour — compared to 16 hours using some traditional methods. According to study results, the device is also about 10 times more sensitive than traditional methods even without using specialized instruments. That means the device can detect cancer biomarkers that are present in smaller quantities, typical of cancer in its early stages. A less sensitive device may not pick up on the smaller quantities, Li said.
Before the device is available to the public, Li said the prototype of the device will need to be finalized and the device tested on patients in a clinical trial, which could take several years. It would require final approval by the Food and Drug Administration before it could be used by physicians.
“Dr. XiuJun Li’s innovation significantly improves point-of-care diagnostics by reducing detection times and the need for costly instruments,” said Robert Kirken, dean of the College of Science. “This makes it ideal for resource-limited settings, which will improve early diagnosis and lead to better cancer outcomes. I look forward to seeing what this innovation leads to.”
An additional co-author on the study is Sanjay Timilsina, Ph.D., a former graduate research assistant at UTEP. Li is a member of the Lab on a Chip advisory board. https://scitechupdates.com/researchers-develop-low-cost-device-that-detects-cancer-in-an-hour/google_vignette https://www.utep.edu/newsfeed/2024/october/utep-researchers-develop-low-cost-device-that-detects-cancer-in-an-hour.html
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