India Makes History With Chandrayaan-3 Landing

August 24, 2023 by Tom Nardi 33 Comments

Yesterday, the Indian Space Research Organization’s (ISRO) Chandrayaan-3 spacecraft performed a powered soft-landing on the Moon, officially making India the fourth country to achieve a controlled descent to the lunar surface. Up to this point, only the United States, China, and the Soviet Union could boast successful landings on our nearest celestial neighbor.

What’s more, Chandrayaan-3 has positioned itself closer to the Moon’s south pole than any other mission in history. This area is of great interest to scientists, as there is evidence that deep craters in the polar region contain considerable deposits of frozen water. At the same time, the polar highlands receive almost constant sunlight, making it the perfect location to install solar arrays. These factors make the Moon’s south pole an ideal candidate for a future human outpost, and Chandrayaan-3 is just one of several robotic craft that will explore this area in the coming years.

But as is usually the case with space exploration, the success of Chandrayaan-3 didn’t come easy, or quickly. The ISRO started the Chandrayaan program in 2003, and launched the Chandrayaan-1 mission in 2008. The craft successfully entered lunar orbit and surveyed the surface using a wide array of instruments, many of which were provided by foreign space agencies such as NASA and the ESA. In 2019 the far more ambitious Chandrayaan-2 mission was launched, which included a lander and small rover. While the orbiter component of Chandrayaan-2 was a complete success, the lander crashed into the Moon’s surface and was destroyed.

With Chandrayaan-3 now safely on the surface of the Moon, there’s much work to be done in the coming days. The planned mission lifetime for both the lander and rover is a single lunar day, which equals just about two weeks here on Earth. After that, the vehicles will be plunged into a long stretch of frigid darkness which they likely won’t survive.

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A Soyuz-2.1b rocket booster with a Fregat upper stage and the Luna 25 lunar lander blasts off from a launchpad at the Vostochny Cosmodrome in Amur Oblast, Russia.

Luna 25’s Demise: Raising Fundamental Questions About Russia’s Space Program

August 21, 2023 by Maya Posch 79 Comments

The recent news that Russia’s Luna 25 Moon lander had made an unexpected lithobraking detour into the Moon’s surface, rather than the expected soft touchdown was met by a variety of responses, ranging from dismay to outright glee, much of it on account of current geopolitical considerations. Yet politics aside, the failure of this mission casts another shadow on the prospects of Russia’s attempts to revive the Soviet space program after a string of failures, including its ill-fated Mars 96 and Fobos-Grunt Mars missions, the latter of which also destroyed China’s first Mars orbiter (Yinghuo-1) and ignited China’s independent Mars program.

To this day, only three nations have managed to land on the Moon in a controlled fashion: the US, China, and the Soviet Union. India may soon join this illustrious list if its Chandrayaan-3 mission’s Vikram lander dodges the many pitfalls of soft touchdowns on the Moon’s surface. While Roscosmos has already started internal investigation, it does cast significant doubt on the viability of the Russian Luna-Glob (‘Lunar Sphere’) lunar exploration program.

Will Russia manage to pick up where the Soviet Union left off in 1976 with the Luna 24 lunar sample return mission?

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Humanity’s Return To The Moon And The Prospect Of South Pole Moon Bases

August 9, 2023 by Maya Posch 31 Comments

The last time that a human set foot on the Moon, it was December 1972 — when the crew of the Apollo 17 mission spent a few days on the surface before returning to Earth. Since then only unmanned probes have either touched down on the lunar surface or entered orbit to take snapshots and perform measurements.

But after years of false starts, there are finally new plans on the table which would see humans return to the Moon. Not just to visit, but with the goal of establishing a permanent presence on the lunar surface. What exactly has changed that the world went from space fever in the 1960s to tepid interest in anything beyond LEO for the past fifty years, to the renewed interest today?

Part of the reason at least appears to be an increasing interest in mineable resources on the Moon, along with the potential of manufacturing in a low gravity environment, and as a jumping-off point for missions to planets beyond Earth, such as Mars and Venus. Even with 1960s technology, the Moon is after all only a few days away from launch to landing, and we know that the lunar surface is rich in silicon dioxide, aluminium oxide as well as other metals and significant amounts of helium-3, enabling in-situ resource utilization.

Current and upcoming Moon missions focus on exploring the lunar south pole in particular, with frozen water presumed to exist in deep craters at both poles. All of which raises the question of we may truly see lunar-based colonies and factories pop up on the Moon this time, or are we merely seeing a repeat of last century?

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When The Sojourner Mars Rover Nearly Ran LISP

August 7, 2023 by Maya Posch 12 Comments

During the late 1980s NASA’s Jet Propulsion Laboratory (JPL) was busy developing the first ever wheeled robot that would roam the surface of Mars. Due to the long round-trip times of any signals between Mars and Earth, development of the firmware that would control the rover was a major point, with the two teams occupied with the task each picking different levels of autonomy for the rover. In a retrospective, [Ron Garrett] who worked at JPL on the ‘more autonomy’ team describes his recollections.

Whereas [Ron]’s team focused on creating a rover that could be provided with high-level instructions which the sophisticated LISP-based firmware would use as guidelines to navigate and operate by, the other team pursued a more limited autonomy approach whereby a human driver would use explicitly plan out the route which the rover would follow before awaiting new instructions.

Perhaps unsurprisingly, the system requirements for running LISP and the additional uncertainties and complexities with the autonomous approach, as well as testing and validating the firmware, resulted in the Sojourner Mars rover featuring the latter approach, with straightforward C-based firmware. Most of Sojourner’s autonomy was limited to a home return function if communication with the lander was lost, which limited both its range and operations during its 85-day extended mission.

As [Ron] covers with examples from later missions, one advantage of LISP is that it allows you to send instructions which can be interpreted (e.g. to debug the system) without having to program in such functionality explicitly. With later Mars rover missions much more of this autonomy that [Ron]’s team pioneered was implemented, although C remained the language of choice for these later rovers.

Heading image: Ron Garrett standing in front of the Robbie prototype. Rocky III can be see in the lower left, and above him are Rajiv Desai and Robert Ivlev, two other members of the team. (Credit: Ron Garret)

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.

Just How Is Voyager 2 Going To Sort Out Its Dish Then?

July 31, 2023 by Jenny List 29 Comments

Anybody who has set up a satellite TV antenna will tell you that alignment is critical when picking up a signal from space. With a satellite dish it’s a straightforward task to tweak the position, but what happens if the dish in question is out beyond the edge of the Solar System?

We told you a few days ago about this exact issue currently facing Voyager 2, but we’re guessing Hackaday readers will want to know a little bit more about how a 50+ year old spacecraft so far from home can still sort out its antenna. The answer lies in NASA Technical Report 32-1559, Digital Canopus Tracker from 1972, which describes the instrument that notes the position of the star Canopus, which along with that of the Sun it can use to calculate the antenna bearing to reach Earth. The report makes for fascinating reading, as it describes how early-1970s technology was used to spot the star by its specific intensity and then keep it in its sights. It’s an extremely accessible design, as even the part numbers are an older version of the familiar 74 logic.

So somewhere out there in interstellar space beyond the boundary of the Solar System is a card frame full of 74 logic that’s been quietly keeping an eye on a star since the early 1970s, and the engineers from those far-off days at JPL are about to save the bacon of the current generation at NASA with their work. We hope that there are some old guys in Pasadena right now with a spring in their step.

Read our coverage of the story here.

Timeline of the universe. A representation of the evolution of the universe over 13.77 billion years. The far left depicts the earliest moment we can now probe, when a period of "inflation" produced a burst of exponential growth in the universe. (Size is depicted by the vertical extent of the grid in this graphic.) For the next several billion years, the expansion of the universe gradually slowed down as the matter in the universe pulled on itself via gravity. More recently, the expansion has begun to speed up again as the repulsive effects of dark energy have come to dominate the expansion of the universe. The afterglow light seen by WMAP was emitted about 375,000 years after inflation and has traversed the universe largely unimpeded since then. The conditions of earlier times are imprinted on this light; it also forms a backlight for later developments of the universe. (Credit: NASA)

ESA’s Euclid Space Telescope And The Quest For Dark Energy

July 31, 2023 by Maya Posch 30 Comments

Most of what humankind and other mammalian species on Earth experience of the Universe is primarily restricted to the part of the electromagnetic spectrum which our optical organs can register. Despite these limitations, we have found ways over the centuries which enable us to perceive the rest of the EM spectrum, to see both what is incredibly far away, and what is incredibly small, to constantly get a little bit closer to understanding what makes the Universe into what we can observe today, and what it may look like in the future.

An essential element of this effort are space telescopes, which gaze into the depths of the Universe with no limitations imposed by the Earth’s atmosphere, or human activity. Among the many uses of space telescopes, the investigation of the expansion of the Universe is perhaps the most fascinating, as this brings us ever closer to the answers to the most fundamental questions about not only its shape, but also to its future, which may include hitherto unknown types of matter and energy.

With the recently launched Euclid space telescope, another chapter is being opened in the saga on dark energy and matter, and their nature and effects on the Universe, as well as whether they exist at all. Yet how exactly do you use a space telescope to ferret out the potential effects of dark energy?

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