Raytracing makes the design easier, but the building is still as tricky as ever.

A 10″ Telescope, Because You Only Live Once

September 16, 2025 by Tyler August 21 Comments

Why build a telescope? YOLO, as the kids say. Having decided that, one must decide what type of far-seer one will construct. For his 10″ reflector, [Carl Anderson] once again said “Yolo”— this time not as a slogan, but in reference to a little-known type of reflecting telescope.

Telescope or sci-fi laser gun? YOLO, just try it.

The Yolo-pattern telescope was proposed by [Art Leonard] back in the 1960s, and was apparently named for a county in California. It differs from the standard Newtonian reflector in that it uses two concave spherical mirrors of very long radius to produce a light path with no obstructions. (This differs from the similar Schiefspiegler that uses a convex secondary.) The Yolo never caught on, in part because of the need to stretch the primary mirror in a warping rig to correct for coma and astigmatism.

[Carl] doesn’t bother with that, instead using modern techniques to precisely calculate and grind the required toric profile into the mirror. Grinding and polishing was done on motorized jigs [Carl] built, save for the very final polishing. (A quick demo video of the polishing machine is embedded below.)

The body of the telescope is a wooden truss, sheathed in plywood. Three-point mirror mounts alowed for the final adjustment. [Carl] seems to prefer observing by eye to astrophotography, as there are no photos through the telescope. Of course, an astrophotographer probably would not have built an F/15 (yes, fifteen) telescope to begin with. The view through the eyepiece on the rear end must be astounding.

If you’re inspired to spend your one life scratch-building a telescope, but want something more conventional, check out this comprehensive guide. You can go bit more modern with 3D printed parts, but you probably don’t want to try spin-casting resin mirrors. Or maybe you do: YOLO!

Continue reading “A 10″ Telescope, Because You Only Live Once” →

See Voyager’s 1990 ‘Solar System Family Portrait’ Debut

September 15, 2025 by Maya Posch 5 Comments

It’s been just over 48 years since Voyager 1 was launched on September 5, 1977 from Cape Canaveral, originally to study our Solar System’s planets. Voyager 1 would explore Jupiter and Saturn, while its twin Voyager 2 took a slightly different route to ogle other planets. This primary mission for both spacecraft completed in early 1990, with NASA holding a press conference on this momentous achievement.

To celebrate the 48th year of the ongoing missions of Voyager 1 and its twin, NASA JPL is sharing an archive video of this press conference. This was the press conference where Carl Sagan referenced the pinpricks of light visible in some images, including Earth’s Pale Blue Dot, which later would become the essay about this seemingly insignificant pinprick of light being the cradle and so far sole hope for the entirety of human civilization.

For most people in attendance at this press conference in June of 1990 it would likely have seemed preposterous to imagine both spacecraft now nearing their half-century of active service in their post-extended Interstellar Mission. With some luck both spacecraft will soon celebrate their 50th launch day, before they will quietly sail on amidst the stars by next decade as a true testament to every engineer and operator on arguably humanity’s most significant achievement in space.

Thanks to [Mark Stevens] for the tip.

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Aussie Researchers Say They Can Bring The Iron Age To Mars

September 13, 2025 by Tyler August 44 Comments

It’s not martian regolith, bu it’s the closest chemical match available to the dirt in Gale Crater. (Image: Swinburne University)

Every school child can tell you these days that Mars is red because it’s rusty. The silicate rock of the martian crust and regolith is very rich in iron oxide. Now Australian researchers at CSIRO and Swinburn University claim they know how to break that iron loose.

In-situ Resource Utilization (IRSU) is a big deal in space exploration, with good reason. Every kilogram of resources you get on site is one you don’t have to fight the tyranny of the rocket equation for. Iron might not be something you’d ever be able to haul from Earth to the next planet over, but when you can make it on site? You can build like a Victoria is still queen and it’s time to flex on the French.

The key to the process seems to be simple pyrolysis: they describe putting dirt that is geochemically analogous to martian regolith into a furnace, and heating to 1000 °C under Martian atmospheric conditions to get iron metal. At 1400 °C, they were getting iron-silicon alloys– likely the stuff steelmakers call ferrosilicon, which isn’t something you’d build a crystal palace with.

It’s not clear how economical piling red dust into a thousand-degree furnace would be on Mars– that’s certainly not going to cut it on Earth– but compared to launch costs from Earth, it’s not unimaginable that martian dirt could be considered ore.

Dragon Is The Latest, And Final, Craft To Reboost ISS

September 11, 2025 by Tom Nardi 48 Comments

The International Space Station has been in orbit around the Earth, at least in some form, since November of 1998 — but not without help. In the vacuum of space, an object in orbit can generally be counted on to remain zipping around more or less forever, but the Station is low enough to experience a bit of atmospheric drag. It isn’t much, but it saps enough velocity from the Station that without regular “reboosts” to speed it back up , the orbiting complex would eventually come crashing down.

Naturally, the United States and Russia were aware of this when they set out to assemble the Station. That’s why early core modules such as Zarya and Zvezda came equipped with thrusters that could be used to not only rotate the complex about all axes, but accelerate it to counteract the impact of drag. Eventually the thrusters on Zarya were disabled, and its propellant tanks were plumbed into Zvezda’s fuel system to provide additional capacity.

An early image of ISS, Zarya module in center and Zvezda at far right.

Visiting spacecraft attached to the Russian side of the ISS can transfer propellant into these combined tanks, and they’ve been topped off regularly over the years. In fact, the NASA paper A Review of In-Space Propellant Transfer Capabilities and Challenges for Missions Involving Propellant Resupply, notes this as one of the most significant examples of practical propellant transfer between orbital vehicles, with more than 40,000 kgs of propellants pumped into the ISS as of 2019.

But while the thrusters on Zvezda are still available for use, it turns out there’s an easier way to accelerate the Station; visiting spacecraft can literally push the orbital complex with their own maneuvering thrusters. Of course this is somewhat easier said than done, and not all vehicles have been able to accomplish the feat, but over the decades several craft have taken on the burden of lifting the ISS into a higher orbit.

Earlier this month, a specially modified SpaceX Cargo Dragon became the newest addition to the list of spacecraft that can perform a reboost. The craft will boost the Station several times over the rest of the year, which will provide valuable data for when it comes time to reverse the process and de-orbit the ISS in the future.

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

TFINER Is An Atompunk Solar Sail Lookalike

September 4, 2025 by Tyler August 16 Comments

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

September 1, 2025 by Maya Posch 29 Comments

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

August 31, 2025 by Maya Posch 43 Comments

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.