Intuitive Machines’ Nova-C Makes It To The Lunar Surface In US Return After Half A Century

February 23, 2024 by Maya Posch 57 Comments

Intuitive Machines’ first mission (IM-1) featuring the Nova-C Odysseus lunar lander was launched on top of a SpaceX Falcon 9 on February 15th, 2024, as part of NASA’s Commercial Lunar Payload Services (CLPS). Targeting a landing site near the lunar south pole, it was supposed to use its onboard laser range finders to help it navigate safely for a soft touchdown on the lunar surface. Unfortunately, it was this component that was found to have malfunctioned as the spacecraft was already in lunar orbit. Fortunately, there was a workaround. By using one of the NASA payloads on the lander, the Navigation Doppler Lidar (NDL), the mission could continue.

Perhaps unsurprisingly, the use of the NDL as a fallback option was considered before launch, and since its functionality overlaps with that of the primary laser range finders of Nova-C, it was pressed into service with a new configuration uploaded by IM operators back on Earth before Nova-C committed to a landing burn. Then, on February 22nd, the spacecraft began its descent to the surface, which also involved the Eaglecam payload that was designed to be released before snapping a self-portrait of the lander as it descended.

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New Modelling Shows That Flat Protoplanets Might Be A Thing

February 20, 2024 by Maya Posch 23 Comments

Surface density of the benchmark run disc (in g cm−2). The disc becomes gravitationally unstable and fragments. Four of the fragments or protoplanets are followed until they reach density 10−3 g cm−3. (Credit: Fenton et al., 2024) — Surface density of the benchmark run disc (in g cm⁻²). The disc becomes gravitationally unstable and fragments. Four of the fragments or protoplanets are followed until they reach density 10⁻³ g cm⁻³. (Credit: Fenton et al., 2024)

While the very idea of a flat planet millions of years after its formation is patently ridiculous, recent modelling shows that during the protostar phase – where material from a nebula is drawn around a hydrostatic core into an accretion disc – it is likely that many of of the protoplanets which form inside a fragmentary protostar accretion disc take on a strongly oblate spheroid shape, rather than a spherical one. This according to [Adam Fenton] and [Dimitris Stamatellos], who ran half a million CPU hours worth of simulation time at the UK’s DiRAC HPC facility, per the University of Central Lancashire (UCLan) press release.

The research was published in the February 2024 issue of Astronomy & Astrophysics, titled The 3D structure of disc-instability protoplanets.

Where this research is essential is not just in our understanding of how our own solar system came to be – including our own oblate spheroid Earth – but also in interpreting what we observe via the Hubble Space Telescope, James Webb Space Telescope and others as we examine areas of the observable Universe such as the Orion Nebula, which is one of the regions with the most actively forming stars. By comparing these simulations with observations, we may find that the simulation matches perfectly, matches partially, or perhaps not at all, which provides data to refine the simulation, but also helps to reconsider how observations were previously interpreted.

All-Sky Camera Checks For Aurora

February 16, 2024 by Bryan Cockfield 4 Comments

The aurora borealis (and its southern equivalent, the aurora australis) is a fleeting and somewhat rare phenomenon that produces vivid curtains of color in the sky at extreme latitudes. It’s a common tourist activity to travel to areas where the aurora is more prevalent in order to catch a glimpse of it. The best opportunities are in the winter though, and since most people don’t want to spend hours outside on a cold night night in high latitudes, an all-sky camera like this one from [Frank] can help notify its users when an aurora is happening.

Because of the extreme temperatures involved, this is a little more involved than simply pointing a camera at the sky and hoping for the best. The enclosure and all electronics need to be able to withstand -50°C and operate at at least -30. For the enclosure, [Frank] is going with PVC tubing with a clear dome glued into a top fits to the end of the pipe, providing a water-resistant enclosure. A Raspberry Pi with a wide-angle lens camera sits on a 3D printed carriage so it can easily slide inside. The electronics use power-over-ethernet (PoE) rather than a battery due to the temperature extremes, which conveniently provides networking capabilities for viewing the images.

This is only part one of this build — in part two [Frank] is planning to build a system which can use this camera assembly to detect the aurora automatically and send out notifications when it sees it. Watching the night sky from the comfort of a warm house or sauna isn’t the only reason for putting an all-sky camera to use, either. They can also be used to observe meteors as they fall and then triangulate the position of the meteorites on the ground.

How Different Are SpaceX Thermal Tiles From The Space Shuttle’s?

February 14, 2024 by Maya Posch 5 Comments

When SpaceX first showed off the thermal tiles on its Starship spacecraft that should keep it safe when re-entering the Earth’s atmosphere towards the loving embrace of the chopsticks on the launch tower, some similarity to the thermal tiles on NASA’s now retired Space Shuttle Orbiter was hard to miss.

Electron microscope image of the fibrous part of a Starship thermal tile, showing very large fibers. (Credit: Breaking Taps, YouTube)

Yet how similar are they really? That’s what the [Breaking Taps] channel on YouTube sought to find out, using an eBay-purchased chunk of Shuttle thermal tile along with bits of Starship tiles that washed ashore following the explosive end to the vehicle’s first integrated test last year.

To answer the basic question: the SpaceX engineers responsible for the Starship thermal tiles seem to have done their homework. An analysis of not only the structure of the fibrous material, but also the black IR-blocking coating, shows that the Starship tiles are highly reminiscent of the EATB (introduced in 1996) tiles with TUFI (toughened unipiece fibrous insulation) coatings with added molybdenum disilicide, which were used during the last years of the Shuttle program.

TUFI is less fragile than the older RCG (reaction cured glass) coating, but also heavier, which is why few TUFI tiles were used on the Shuttles due to weight concerns. An oddity with the Starship tiles is that they incorporate many very large fibers, which could be by design, or indicative of something else.

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The Usage Of Embedded Linux In Spacecraft

February 10, 2024 by Maya Posch 44 Comments

As the first part of a series, [George Emad] takes us through a few examples of the Linux operating system being used in spacecraft. These range from SpaceX’s Dragon capsule to everyone’s favorite Martian helicopter. An interesting aspect is that the freshest Linux kernel isn’t necessarily onboard, as stability is far more important than having the latest whizzbang features. This is why SpaceX uses Linux kernel 3.2 (with real-time patches) on the primary flight computers of both Dragon and its rockets (Falcon 9 and Starship).

SpaceX’s flight computers use the typical triple redundancy setup, with three independent dual-core processors running the exact same calculations and a different Linux instance on each of its cores, and the result being compared afterwards. If any result doesn’t match that of the others, it is dropped. This approach also allows SpaceX to use fairly off-the-shelf (OTS) x86 computing hardware, with the flight software written in C++.

NASA’s efforts are similar, with Ingenuity in particular heavily using OTS parts, along with NASA’s open source, C++-based F’ (F Prime) framework. The chopper also uses some version of the Linux kernel on a Snapdragon 801 SoC, which as we have seen over the past 72 flights works very well.

Which is not to say using Linux is a no-brainer when it comes to use in avionics and similar critical applications. There is a lot of code in the monolithic Linux kernel that requires you to customize it for a specific task, especially if it’s on a resource-constrained platform. Linux isn’t particularly good at hard real-time applications either, but using it does provide access to a wealth of software and documentation — something that needs to be weighed up against the project’s needs.

Flipped Bit Could Mark The End Of Voyager 1‘s Interstellar Mission

February 9, 2024 by Dan Maloney 95 Comments

Sometimes it’s hard to read the tea leaves of what’s going on with high-profile space missions. Weighted down as they are with the need to be careful with taxpayer money and having so much national prestige on the line, space agencies are usually pretty cagey about what’s going on up there. But when project managers talk about needing a “miracle” to continue a project, you know things have gotten serious.

And so things now sit with Voyager 1, humanity’s most distant scientific outpost, currently careening away from Mother Earth at 17 kilometers every second and unable to transmit useful scientific or engineering data back to us across nearly a light-day of space. The problem with the 46-year-old spacecraft cropped up back in November, when Voyager started sending gibberish back to Earth. NASA publicly discussed the problem in December, initially blaming it on the telemetry modulation unit (TMU) that packages data from the remaining operable scientific instruments along with engineering data for transmission back to Earth. It appeared at the time that the TMU was not properly communicating with the flight data system (FDS), the main flight computer aboard the spacecraft.

Since then, flight controllers have determined that the problem lies within the one remaining FDS on board (the backup FDS failed back in 1981), most likely thanks to a single bit of corrupted memory. The Deep Space Network is still receiving carrier signals from Voyager, meaning its 3.7-meter high-gain antenna is still pointing back at Earth, so that’s encouraging. But with the corrupt memory, they’ve got no engineering data from the spacecraft to confirm their hypothesis.

The team has tried rebooting the FDS, to no avail. They’re currently evaluating a plan to send commands to put the spacecraft into a flight mode last used during its planetary fly-bys, in the hope that will yield some clues about where the memory is corrupted, if indeed it is. But without a simulator to test the changes, and with most of the engineers who originally built the spacecraft long gone now, the team is treading very carefully.

Voyager 1 is long past warranty, of course, and with an unparalleled record of discovery, it doesn’t owe us anything at this point. But we’re not quite ready to see it slip into its long interstellar sleep, and we wish the team good luck while it works through the issue.

A schematic representation of the different ionospheric sub-layers and how they evolve daily from day to night periods. (Credit: Carlos Molina)

Will Large Satellite Constellations Affect Earth’s Magnetic Field?

February 7, 2024 by Maya Posch 48 Comments

Imagine taking a significant amount of metals and other materials out of the Earth’s crust and scattering it into the atmosphere from space. This is effectively what we have been doing ever since the beginning of the Space Age, with an increasing number of rocket stages, satellites and related objects ending their existence as they burn up in the Earth’s atmosphere. Yet rather than vanish into nothing, the debris of this destruction remains partially in the atmosphere, where it forms pockets of material. As this material is often conductive, it will likely affect the Earth’s magnetic field, as argued by [Sierra Solter-Hunt] in a pre-publication article.

A summary by [Dr. Tony Phillips] references a 2023 NASA research article by [Daniel M. Murphy] et al. which describes the discovery that about 10% of the aerosol particles in the stratosphere are aluminium and other metals whose origin can be traced back to the ‘burn-up’ of the aforementioned space objects. This is a factor which can increase the Debye length of the ionosphere. What the exact effects of this may be is still largely unknown, but fact remains that we are launching massively more objects into space than even a decade ago, with the number of LEO objects consequently increasing.

Although the speculation by [Sierra] can be called ‘alarmist’, the research question of what’ll happen if over the coming years we’ll have daily Starlink and other satellites disintegrating in the atmosphere is a valid one. As this looks like it will coat the stratosphere and ionosphere in particular with metal aerosols at levels never seen before, it might be worth it to do the research up-front, rather than wait until we see something odd happening.