Figure 7-8, caption: Example thrust sheet rotation using tether control. Credit: NASA/James Bickford.

TFINER Is An Atompunk Solar Sail Lookalike

It’s not every day we hear of a new space propulsion method. Even rarer to hear of one that actually seems halfway practical. Yet that’s what we have in the case of TFINER, a proposal by [James A. Bickford] we found summarized on Centauri Dreams by [Paul Gilster] .

TFINER stands for Thin-Film Nuclear Engine Rocket Engine, and it’s a hoot.  The word “rocket” is in the name, so you know there’s got to be some reaction mass, but this thing looks more like a solar sail. The secret is that the “sail” is the rocket: as the name implies, it hosts a thin film of nuclear materialwhose decay products provide the reaction mass. (In the Phase I study for NASA’s Innovative Advanced Concepts office (NIAC), it’s alpha particles from Thorium-228 or Radium-228.) Alpha particles go pretty quick (about 5% c for these isotopes), so the ISP on this thing is amazing. (1.81 million seconds!) Continue reading “TFINER Is An Atompunk Solar Sail Lookalike”

NASA Seeks Volunteers To Track Artemis II Mission

As NASA’s Artemis program trundles onwards at the blazing pace of a disused and very rusty crawler-transporter, the next mission on the list is gradually coming into focus. This will be the first crewed mission — a flyby of the Moon following in the footsteps of 1968’s Apollo 8 mission. As part of this effort, NASA is looking for volunteers who will passively track the Orion capsule and its crew of four as it makes its way around the Moon during its 10-day mission before returning to Earth. Details can be found here.

This follows on a similar initiative during the Artemis I mission, when participants passively tracked the radio signals from the capsule. For this upcoming mission NASA is looking for Doppler shift measurements on the Orion S-band (2200-2290 MHz) return link carrier signals, with the objective being to achieve and maintain a carrier lock.

Currently penciled in for a highly tentative April 2026, the Artemis II mission would fly on the same SLS Block 1 rocket configuration that launched the first mission, targeting a multi-trans-lunar injection (MTLI) profile to get to the Moon using a free return trajectory. The crew will check out the new life support system prior to starting the MTLI burns.

Because Artemis II will be on a free return trajectory it will not be orbiting the Moon, unlike Apollo 8’s crew who made ten lunar orbits. Incidentally, Apollo 8’s crew included James Lovell, who’d go on to fly the world-famous Apollo 13 mission. Hopefully the Artemis astronauts will be spared that level of in-space excitement.

NASA Is Taking Suggestions For Raising Swift’s Orbit

Launched in 2004, the Neil Gehrels Swift Observatory – formerly the Swift Gamma-Ray Burst Explorer – has been dutifully studying gamma-ray bursts (GRBs) during its two-year mission, before moving on to a more general space observation role during its ongoing mission. Unfortunately, the observatory is in LEO, at an altitude of around 370 km. The natural orbital decay combined with increased solar activity now threatens to end Swift’s mission, unless NASA can find someone who can boost its orbit.

Using Swift as a testbed for commercial orbit-boosting technologies, NASA is working with a number of companies to investigate options. One of these is the SSPICY demonstration of in-orbit inspection technology by Starfish Space that’s part of an existing Phase III program.

Although currently no option has been selected and Swift is still at risk of re-entering Earth’s atmosphere within the near future, there seems to be at least a glimmer of hope that this process can be reverted, and a perfectly fine triple-telescope space observatory can keep doing science for many years to come. Along the way it may also provide a blueprint for how to do the same with other LEO assets that are at risk of meeting a fiery demise.

Illustration of a Gemini B reentry vehicle separating from the Manned Orbiting Laboratory (MOL). (Source: US Air Force)

The Advanced Project Gemini Concepts That Could Have Been

Looking back on the trajectory leading to Project Apollo and the resulting Moon missions, one can be forgiven for thinking that this was a strict and well-defined plan that was being executed, especially considering the absolute time crunch. The reality is that much of this trajectory was in flux, with the earlier Project Gemini seeing developments towards supplying manned space stations and even its own Moon missions. [Spaceflight Histories] recently examined some of these Advanced Gemini concepts that never came to pass.

In retrospect, some of these seem like an obvious evolution of the program. Given both NASA and the US Air Force’s interest in space stations at the time, the fact that a up-sized “Big Gemini” was proposed as a resupply craft makes sense. Not to be confused with the Gemini B, which was a version of the spacecraft that featured an attached laboratory module. Other concepts, like the paraglider landing feature, were found to be too complex and failure prone.

The circumlunar, lunar landing and Apollo rescue concepts were decidedly more ambitious and included a range of alternatives to the Project Apollo missions, which were anything but certain especially after the Apollo 1 disaster. Although little of Advanced Gemini made it even into a prototype stage, it’s still a fascinating glimpse at an alternate reality.

Continue reading “The Advanced Project Gemini Concepts That Could Have Been”

Where There Is No Down: Measuring Liquid Levels In Space

As you can probably imagine, we get tips on a lot of really interesting projects here at Hackaday. Most are pretty serious, at least insofar as they aim to solve a specific problem in some new and clever way. Some, though, are a little more lighthearted, such as a fun project that came across the tips line back in May. Charmingly dubbed “pISSStream,” the project taps into NASA’s official public telemetry stream for the International Space Station to display the current level of the urine tank on the Space Station.

Now, there are a couple of reactions to a project like this when it comes across your desk. First and foremost is bemusement that someone would spend time and effort on a project like this — not that we don’t appreciate it; the icons alone are worth the price of admission. Next is sheer amazement that NASA provides access to a parameter like this in its public API, with a close second being the temptation to look at what other cool endpoints they expose.

But for my part, the first thing I thought of when I saw that project was, “How do they even measure liquid levels in space?” In a place where up and down don’t really have any practical meaning, the engineering challenges of liquid measurement must be pretty interesting. That led me down the rabbit hole of low-gravity process engineering, a field that takes everything you know about how fluids behave and flushes it into the space toilet.

Continue reading “Where There Is No Down: Measuring Liquid Levels In Space”

One of the photo-detector spheres of ARCA (Credit: KM3NeT)

Confirmation Of Record 220 PeV Cosmic Neutrino Hit On Earth

Neutrinos are exceedingly common in the Universe, with billions of them zipping around us throughout the day from a variety of sources. Due to their extremely low mass and no electric charge they barely ever interact with other particles, making these so-called ‘ghost particles’ very hard to detect. That said, when they do interact the result is rather spectacular as they impart significant kinetic energy. The resulting flash of energy is used by neutrino detectors, with most neutrinos generally pegging out at around 10 petaelectronvolt (PeV), except for a 2023 event.

This neutrino event which occurred on February 13th back in 2023 was detected by the KM3NeT/ARCA detector and has now been classified as an ultra-high energy neutrino event at 220 PeV, suggesting that it was likely a cosmogenic neutrinos. When we originally reported on this KM3-230213A event, the data was still being analyzed based on a detected muon from the neutrino interaction even, with the researchers also having to exclude the possibility of it being a sensor glitch.

By comparing the KM3-230213A event data with data from other events at other detectors, it was possible to deduce that the most likely explanation was one of these ultra-high energy neutrinos. Since these are relatively rare compared to neutrinos that originate within or near Earth’s solar system, it’ll likely take a while for more of these detection events. As the KM3NeT/ARCA detector grid is still being expanded, we may see many more of them in Earth’s oceans. After all, if a neutrino hits a particle but there’s no sensor around to detect it, we’d never know it happened.


Top image: One of the photo-detector spheres of ARCA (Credit: KM3NeT)

How’s The Weather? (Satellite Edition)

When [Tom Nardi] reported on NOAA’s statement that many of its polar birds were no longer recommended for use, he mentioned that when the satellites do give up, there are other options if you want to pull up your own satellite weather imagery. [Jacopo] explains those other options in great detail.

For example, the Russian Meteor-M satellites are available with almost the same hardware and software stack, although [Jacopo] mentions you might need an extra filter since it is a little less tolerant of interference than the NOAA bird. On the plus side, Meteor-M is stronger than the NOAA satellite on 1.7 GHz, and you can even use a handheld antenna to pick it up. There are new, improved satellites of this series on their way, too.

Continue reading “How’s The Weather? (Satellite Edition)”