Voyager 2: Communication Reestablished With One Big Shout

August 4, 2023 by Dan Maloney 35 Comments

You could practically hear the collective “PHEW!” as NASA announced that they had reestablished full two-way communications with Voyager 2 on Friday afternoon! Details are few at this point — hopefully we’ll get more information on how this was pulled off, since we suspect there was some interesting wizardry involved. If you haven’t been following along, here’s a quick recap of the situation.

As we previously reported, a wayward command that was sent to Voyager 2, currently almost 19 light-hours distant from Earth, reoriented the spacecraft by a mere two degrees. It doesn’t sound like much, but the very narrow beamwidth on Voyager‘s high-gain antenna and the vast distance put it out of touch with the Canberra Deep Space Network station, currently the only ground station with line-of-sight to the spacecraft. While this was certainly a problem, NASA controllers seemed to take it in stride thanks to a contingency program which would automatically force the spacecraft to realign itself to point at Earth using its Canopus star tracker. The only catch was, that system wasn’t set to engage until October.

With this latest development, it appears that mission controllers weren’t willing to wait that long. Instead, based on what was universally referred to in the non-tech media as a “heartbeat” from Voyager on August 1– it appears that what they were really talking about was the use of multiple antennas at the Canberra site to pick up a weak carrier signal from the probe — they decided to send an “interstellar shout” and attempt to reorient the antenna. The 70-m DSS-43 dish blasted out the message early in the morning of August 2, and 37 hours later, science and engineering data started streaming into the antenna again, indicating that Voyager 2 was pointing back at Earth and operating fine.

Hats off to everyone involved in making this fix and getting humanity’s most remote outpost back online. If you want to follow the heroics in nearly real-time, or just like watching what goes on at the intersection of Big Engineering and Big Science, make sure you check out the Canberra DSN Twitter feed.

Discussing The Finer Points Of Space-Worthy Software

July 17, 2023 by Tom Nardi 28 Comments

At the dawn of the Space Race, when computers were something that took up whole rooms, satellites and probes had to rely on analog electronics to read from their various sensors and transmit the resulting data to the ground. But it wasn’t long before humanity’s space ambitions outgrew these early systems, which lead to vast advancements in space-bound digital computers in support of NASA’s Gemini and Apollo programs. Today, building a spacecraft without an onboard computer (or even multiple redundant computers) is unheard of. Even the smallest of CubeSats is likely running Linux on a multi-core system.

As such, software development has now become part an integral part of spacecraft design — from low-level code that’s responsible for firing off emergency systems to the 3D graphical touchscreen interfaces used by the crew to navigate the craft. But as you might expect, the stakes here are higher than any normal programming assignment. If your code locks up here on Earth, it’s an annoyance. If it locks up on a lunar lander seconds before it touches down on the surface, it could be the end of the mission.

To get a bit more insight into this fascinating corner of software development, we invited Jacob Killelea to host last week’s
Software for Satellites Hack Chat. Jacob is an engineer with a background in both aero and thermodynamics, control systems, and life support. He’s written code for spacecraft destined for the Moon, and perhaps most importantly, is an avid reader of Hackaday.

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Laser Propulsion Could Satisfy Our Spacecraft’s Need For Speed

June 6, 2022 by Lewin Day 51 Comments

There are many wonderful places we’d like to visit in the universe, and probably untold numbers more that we haven’t even seen or heard of yet. Unfortunately…they’re all so darn far away. A best-case-scenario trip to Mars takes around six months with present technology, meanwhile, if you want to visit Alpha Centauri it’s a whole four lightyears away!

When it comes to crossing these great distances, conventional chemical rocket technology simply doesn’t cut the mustard. As it turns out though, lasers could hold the key to cutting down travel times in space!

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Mercury Thrusters: A Worldwide Disaster Averted Just In Time

April 18, 2022 by Lewin Day 60 Comments

The field of space vehicle design is obsessed with efficiency by necessity. The cost to do anything in space is astronomical, and also heavily tied to launch weight. Thus, any technology or technique that can bring those figures down is prime for exploitation.

In recent years, mercury thrusters promised to be one such technology. The only catch was the potentially-ruinous environmental cost. Today, we’ll look at the benefits of mercury thrusters, and how they came to be outlawed in short order.

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Apollo Comms Flight Hardware Deep Dive

January 21, 2022 by Chris Lott 6 Comments

You no doubt recall the incredible Apollo Guidance Computer (AGC) reverse engineering and restoration project featured on the CuriousMarc YouTube channel a few years ago. Well, [Marc] and the team are at it again, this time restoring the Apollo Unified S-Band tracking and communication system flight hardware. As always, the project is well documented, carefully explained, full of problems, and is proceeding slowly despite the lack of documentation.

Like the guidance computer, the Unified S-Band system was pretty innovative for its day — able to track, provide voice communications, receive television signals, and send commands to and monitor the health of the spacecraft via telemetry. The system operates on three frequencies, an uplink containing ranging code, voice and data. There are two downlinks, one providing ranging, voice, and telemetry, the other used for television and the playback of recorded data. All crammed into two hefty boxes totaling 29 kg.

So far, [Marc] has released part 9 of the series (for reference, the Apollo Guidance Computer took 27 parts plus 8 auxiliary videos). There seems to be even less documentation for this equipment than the AGC, although miraculously the guys keep uncovering more and more as things progress. Also random pieces of essential ground test hardware keep coming out of the woodwork. It’s a fascinating dive into not only the system itself, but the design and construction techniques of the era. Be sure to check out the series (part 1 is below the break) and follow along as they bring this system back to life. [Marc] is posting various documents related to the project on his website. And if you missed the AGC project, here’s the playlist of videos, and the team joined us for a Hackaday Chat back in 2020.

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Spacing Out: Telescopes, Politics, And Spacecraft Design

December 7, 2021 by Jenny List 9 Comments

Let’s launch into a round-up of stories that are out of this world, as we take a look at what’s happening in the realm of space exploration.

Ten Billion Dollars For A Telescope? Don’t Drop It!

Perhaps the most highly anticipated space mission of the moment is the James Webb Space Telescope, an infra-red telescope that will be placed in an orbit around the Earth-Sun L2 Lagrange point from which it will serve as the successor to the now long-in-the-tooth Hubble telescope. After many years of development the craft has been assembled and shipped to French Guiana for a scheduled Ariane 5 launch on the 22nd of December. We can only imagine what must have gone through the minds of the engineers and technicians working on the telescope when an unplanned release of a clamp band securing it to the launch vehicle adapter sent a vibration throughout the craft. Given the fragility of some of its components this could have jeopardised the mission, however after inspection it was found that no damage had occurred and that space-watchers and astronomers alike can breathe easy.

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NASA’s Lucy Stretches Its Wings Ahead Of Trojan Trek

April 10, 2021 by Zach Zeman 4 Comments

The good news about using solar power to explore space is there are no clouds to block your sunlight. Some dust and debris, yes, but nowhere near what we have to deal with on planets. The bad news is, as you wander further and further out in the solar system, your panels capture less and less of the sunlight you need for power. NASA’s Lucy spacecraft will be dependent on every square inch, so we’re happy to hear technicians have successfully tested its solar panel deployment in preparation for an October 2021 launch.

An animation of Trojan asteroids and inner planets in orbit around the Sun. — Trojan asteroids (in green) orbit the Sun ahead of and behind Jupiter.

Lucy’s 12-year mission is to examine one Main Belt asteroid and seven so-called Trojans, which are asteroids shepherded around the Sun in two clusters at Lagrange points just ahead and behind Jupiter in its orbit. The convoluted orbital path required for all those visits will sling the spacecraft farther from the sun than any solar-powered space mission has gone before. To make up for the subsequent loss of watts per area, the designers have done their best to maximize the area. Though the panels fold up to a package only 4 inches (10 centimeters) thick, they open up to an enormous diameter of almost 24 feet (7.3 meters); which is enough to provide the roughly 500 watts required at literally astronomical distances from their power source.

Near-Earth asteroids are exciting targets for exploration partly because of the hazards they pose to our planet. Trojan asteroids, thought to be primordial remnants of the same material that formed the outer planets, pose no such danger to us but may hold insights about the early formation of our solar system. We’re already eagerly anticipating the return of OSIRIS-REx’s sample, and Hayabusa2 continues its mission after so many firsts. An extended tour of these farther-off objects will keep us watching for years to come. Check out the video embedded below for Lucy’s mission overview.

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