Tag: Spaceflight

It is perhaps the unsung hero of space launch capabilities. Whilst the media focuses on its darling Falcon 9 – a vehicle which, to be sure, is innovative, successful and highly flexible -, or reflects on Russia’s veritable (if sometimes troublesome) Soyuz family, Europe’s Ariane 5 has quietly gone about the business of lifting payloads to various orbits and a deep space missions for 28 years, barely coming to prominence in the news, unless in exceptional circumstances. Such as on the occasion of its final flight, as has been the case this past week. This is a shame, because the Ariane 5 project has been remarkably successful.

First flown in 1996 as the latest iteration of the Ariane family, the rocket’s history goes back to the 1970s, when an Anglo-French-German project was established to develop a new commercial launch vehicle for Western Europe. Christened “Ariane” – the French spelling of the mythological character Ariadne – the project became largely French-driven but within the auspices of the European Space Agency (ESA). The latter charged Airbus Defence and Space with the development of all Ariane vehicles and all related testing facilities, whilst CNES, the French national space agency, spun-up a commercial operation called Arianespace – in which they retain around a 32.5% stake – to handle production, operations, marketing and launches of the Ariane family, the latter being made out of Europe’s Spaceport, aka the Guiana Space Centre at Kourou in French Guiana.

Arianespace was the world’s first commercial launch provider, initially offering customer launches atop the evolving family of Ariane vehicles, commencing with Ariane 1 in 1979. Then, from 2003 through 2019, then partnership with Russia to provide medium-lift launch capabilities utilising  the Soyuz-ST payload carrier under the Arianespace Soyuz programme, becoming the only facility to operate Soyuz vehicles outside of Russia (until the latter’s invasion of Ukraine brought the partnership to an end). In 2012, Arianespace further supplement its range of capabilities by adding the Italian-led Vega small payloads vehicle to their launch vehicle catalogue.

Ariane 5 was first launched in June 1996 in what was called the G(eneric) variant, capable of lifting 16 tonnes to low Earth orbit (LEO) or up to 6.95 tonnes to  geosynchronous transfer orbit (GTO). Over the coming years, it iterated through four evolutions – G+, GS, ECA, and ES – each bringing about a range of performance and other improvements which raised the vehicle’s maximum lift capabilities to 21 tonnes of payload to LEO and 10.86 tonnes to GTO whilst also allowing Arianespace to lower launch fees to customers. In addition – and while it was never used in such a capacity – Ariane 5 is the only member of the Ariane family to be designed for crewed launches, in part being designed to carry the Hermes space plane to orbit (of which more below).

In all, Ariane 5 flew a total of 117 launches from 1996 onwards, suffering three partial and two complete failures to deliver payloads as intended, with an maximum launch cadence of 7 per year. Notable among these launches are:

December 10^th, 1999: the X-ray Multi-Mirror Mission (XMM-Newton). Itself an oft-overlooked mission when compared to NASA’s Great Observatories programme, XMM-Newton was one of the four “cornerstone” missions of the Horizon 2000 chapter of ESA’s science missions.

Named for English physicist and astronomer Sir Isaac Newton, the spacecraft comprises 3 X-ray telescopes feeding a range of science instruments and imaging systems. Its primary mission is the study of interstellar X-ray sources in both narrow- and broad-range spectroscopy, and performing the first simultaneous imaging of objects in both X-ray and optical (visible + ultraviolet) wavelengths. The programme was initially funded for two years, but its most recent mission extension will see it funded through until the end of 2026 – with the potential (vehicle conditions allowing) – for it to be extended up to the launch of its “replacement” mission, the  Advanced Telescope for High Energy Astrophysics (ATHENA), due to commence operations in 2035/6. As of May 2018, XMM had generated more than 5,600 research papers.

March 2^nd 2004: Rosetta. Another Horizon 2000 “cornerstone” mission, Rosetta spent 10 years using the inner solar system to allow it to rendezvous with the nucleus of comet 67P/Churyumov–Gerasimenko – the first space vehicle to enter orbit around a comet following its arrival on August 6^th, 2014.

For two years, the vehicle revealed an enormous amount about the comet, although it was perhaps overshadowed in the public consciousness by the adventures of the little Philae lander Rosetta dispatched to the surface of the comet, and which captured hearts and minds with its struggles.

May 14^th, 2009: Herschel Space Observatory and Planck Observatory. These two ground-breaking missions were delivered to the Erath-Sun Lagrange L₂ position (yes, the one also used by the James Webb Space Telescope – JWST -, and the one the Euclid mission will utilise where it arrives in an extended halo orbit around it in August 2023). Whilst separate missions, both spacecraft were launched on the same Ariane 5 booster and each utilised a service module built to a common design.

Initially planned for a 15-month primary mission, Planck – named for German physicist Max Planck – ran for just under 4.5 years, concluding in 2013 after on-board supplies of liquid helium were exhausted, and the primary instruments could longer be cooled to their required operating temperatures. As fuel remained for the craft’s manoeuvring thrusters, Planck was ordered to move away from the L₂ position and into a heliocentric orbit, where its systems were decommissioned and the vehicle shut down.

The Herschel Space Observatory, meanwhile, operated for just over 4 years, and was the largest infrared telescope ever launched until the James Webb Space Telescope. It was yet another “cornerstone” mission for Horizon 2000, and was named for Sir William Herschel, the discoverer of the infrared spectrum. Its primary objectives comprised investigating clues for the formation of galaxies in the early universe, the nature of molecular chemistry across the universe, the interaction of star formation with the interstellar medium and, closer to home, the chemical composition of atmospheres and surfaces of planets, moons and comets within our solar system. In this regard, the observatory amassed more the 25,000 hours of science data used by 600 different science programmes.

 October 20^th, 2018: BepiColumbo. Undertaken by ESA and the Japan Aerospace Exploration Agency (JAXA), BepiColumbo is the overall mission title given to two vehicles and their transfer bus, all launched as a “stack” via Ariane 5, in a mission to carry out a comprehensive study Mercury, the innermost planet of the solar system. It is named after  Italian scientist and mathematician Giuseppe “Bepi” Colombo.

Despite its orbit being relative close to Earth (when compared to the outer planets of the solar system that is), Mercury’s is one of the most technically complex to reach. “Bepi” Columbo calculated a vehicle could use a solar orbit and multiple fly-bys of the inner planets to reach Mercury in an energy-efficient manner – and it is this style of approach the mission is using to reach its destination. It has already completed five gravity assist manoeuvres (1 around Earth in 2020, two around Venus in 2020 and 2021 and 2 around Mercury in 2021 and 2022). A further fiver fly-bys of Mercury will occur in 2024/25 to bring the mission to its primary science orbit around the planet at the end of 2025.

At that time the vehicles will separate, the transfer bus, called the Mercury Transfer Module being discarded to allow the 1.1 tonne ESA-built Mercury Planetary Orbited (MPO) to commence what is expected to be at least one terrestrial year of operations studying the planet. During the initial phase of this mission, MPO will in turn deploy the Japanese-built Mio vehicle into its own orbit around Mercury, where it is also expected to operate for at least a terrestrial year.

Continue reading “Space Sunday: saying adieu to Ariane 5 and recalling Hermes” →

Rotating crews to / from a space station is so routine here in the west that the comings and going of crews at the International Space Station (ISS) rarely gain much of a mention unless something extraordinary happens, or they happen to be entirely privately-funded, as with the Axiom Space Ax-2 mission (of which more below).

Not so for the Chinese, however, who are still adjusting to life with an orbital outpost that is meant to remain under permanent occupation and also provide a stepping stone towards the Moon. What’s more, they are gradually become more public about things as they continue to rake up successes.

Following the completion of “construction” of the major elements of the Tiangong space station with the docking of the second science module in November 2022, the Shenzhou 15 crew, comprising taikonauts Fei Junlong, Deng Qingming and Zhang Lu have been at work commissioning the module and carrying out further work in preparing the station for full-time operations, building on the work of the Shenzhou 14 crew, as well as performing a full science programme.

On May 30^th, they were joined by the crew of Shenzhou 16, who performed a “fast burn” flight to rendezvous and dock with Tiangong just seven hours after their launch from the Jiuquan Satellite Launch Centre in the Gobi Desert. This crew has garnered a lot of attention both nationally and internationally, as it includes China’s first non-military tiakonaut to fly in space: professor Gui Haichao, an aerospace researcher who has studied and taught in China and Canada.

The entire launch was covered live on Chinese national television, as was the rendezvous and docking, summarised for new broadcasts and viewing in the west in videos like the one below.

Gui is joined on the mission by commander Major General Jing Haipeng of the People’s Liberation Army Air Force (PLAAF), and rookie taikonaut Colonel Zhu Yangzhu of the People’s Liberation Army. Scheduled for a duration of 180 days, the mission will see Jing become China’s most experienced taikonaut, with four missions under his belt and clocking up over 225 days (cumulative) in orbit.

Following docking, the Shenzhou 16 crew remained with the three men of Shenzhou 15 Through until the weekend, when the Shenzhou 15 crew departed the space station late on Saturday, June 3^rd (Beijing time), to commence a 9-hour return to Earth, where they touched down at the Dongfeng landing site within North China’s Inner Mongolia autonomous region at 06:33 on Sunday, June 4^th (Beijing time – (22:33 UTC on June 3rd).

The landing was also covered in detail by the Chinese media, and as with the Russian approach to crew returning from long duration orbital flights, the three men were not allowed to spend time standing or moving under their own power; instead they were helped out of their craft and into waiting chairs, where they were interviewed by a China Central Television (CCTV) crew in a live broadcast. This focused on Senior Colonel Deng Qingming, quite possibly one of the longest-serving astronauts-in-waiting in the world prior to lifting-off on this mission, having been in the PLA taikonaut corps for 26 years! He is actually the last of China’s “first generation” intake of astronauts to fly into space, and his perseverance has made him an icon on the PLA space corps.

In between Shenzhou 16 lifting-off for Tiangong and Shenzhoou 15 returning, the crew of Axiom AX-2 also wrapped up their stay at the International Space Station and returned to Earth.

As the name indicates, this was that second Axiom Space crewed mission to the ISS, carried out as part of the company’s progress towards running its own space station, and delivered a crew of four astronauts to the ISS for a period of eight days. Aboard were former astronaut Peggy Whiston as mission commander, John Shoffner, an aviator and entrepreneur, Ali AlQarni, a captain in the Royal Saudi Air Force and Rayyanah Barnawi, and Saudi biomedial researcher and the first Saudi woman to fly in space.

The mission lifted-off from Kennedy Space Centre atop a Falcon 9 rocket on May 21^st, 2023, and the Crew Dragon Freedom docked with the Harmony module of the ISS a day later. During their time on the station, the crew performed public outreach activities along with scientific research, including studies into the effects of microgravity on stem cells and other biological experiments which had been agreed with the Saudi Space Commission as part of the deal to fly the two Saudi nationals on the mission.

For Whitson, it was a fourth opportunity to fly in space and add to an already impressive record: in her first mission, she spent an extended mission on the ISS, in her second she became the first woman to command the ISS (and later became the first women to complete two tours on the ISS as mission commander), she has completed the most EVAs (spacewalks) thus far for a woman, having spent a total of 60 hours and 21 minutes outside of the ISS performing various tasks; she has spent a total of 675 days in space during her career and remains the oldest woman to orbit the Earth. She was also the first woman to become NASA’s Chief Astronaut, the most senior position in the NASA Astronaut Corps.

For the rest of the crew, it was the opportunity to experience space for the first time, and for Axiom Space, a further opportunity to study managing orbital operations and research endeavours of the kind they hope to both manage and host on their own space station. The latter is due to start life as modules attached to the ISS (and referred to as the Axiom Orbital Segment) in the late 2020s, before becoming an independent orbital facility when the ISS is decommissioned at the start of the 2030s.

On May 30^th, 2023, the crew re-boarded Freedom and departed the ISS, splashing down successfully in the Gulf of Mexico off the coast of Panama City, Florida in the early hours of May 31^st, local time, where it was recovered by the SpaceX recovery ship Megan.

Spaceport Company Performs At-Sea Launches

Landing returning crewed spacecraft on the world’s seas – as with the AX-2 mission – has long been a thing for the United States. However, it has also been the dream of some to use the oceans as a means of launching vehicles into orbit – perhaps most famously (thanks to it being referenced in the Apple TV series For All Mankind), the simply gargantuan Sea Dragon. Planned in the 1960s but never built, this behemoth was designed to lift 550 tonnes of cargo to orbit – and to start its journey by floating in open waters off the US coast.

Obviously, Sea Dragon never came to be, but in 1999, a multi-national corporation – Sea Launch – commenced payload launches from the deck of a modified oil rig – the Odyssey, operating in the Pacific Ocean close to the equator – using a specialised version of the Russian Zenit-3SL. The company carried out a total of 36 such launches from 1999 through 2014, when Russia’s first military incursion into Ukraine (which ultimately brought an end to the company), suffering only four failures.

Now a US company – the appropriately-named The Spaceport Company – has hosted four sounding rocket launches with the support of Evolution Space, from a platform in the Gulf of Mexico. The launches were the latest step of a proof-of-concept study the company is carrying out into the feasibility of conducting payload-to-orbit flights from mobile platforms operating off the US coast.

In particular, the company stated the operation – performed on May 22^nd – was intended to exercise the procedures -including getting approvals from the Federal Aviation Administration and U.S. Coast Guard, clearing airspace and waters to allow for a safe launch  – before any actual rocket launch from the platform.

The company plans to plans to use the platforms – called liftboats – which can sail / be towed to a designated location before temporarily anchoring itself to the sea bed by means of four legs which can be extended down into the water to a depth of up to 50 metres, and also left the platform clear of the water. A second platform then acts as the launch control centre, freeing launches from the need of any land-based infrastructure, outside of a docking and servicing facility with the means to accept launch vehicles and move them onto the launch platform safely.

These platforms will be capable of being deployed almost anywhere of the US coast, although the company particularly hopes to leverage the increasing demand for launches out of both the Cape Canaveral Space Force Station and Kennedy Space Centre. presenting companies operating smaller rocket systems with a viable off-shore alternative.

Both The Spaceport company and Evolution Space (who providing the rocket systems for the May 22^nd launches) kept quiet about the event itself, only releasing a post-launch briefing on the launches 24 hours after they had taken place.  Further test flights on the platform are expected over the course of the nest two years, and the company is targeting 2025 for its first full-scale, fully commercial payload launch.

Continue reading “Space Sunday: launches and landings” →

China has been making a lot of space-related news recently, so it’s time to catch-up on things.

At the end of April, the country confirmed it intends to have boots on the Moon by 2030. This confirmation came during a wide-ranging interview with Wu Weiren, the head of the country’s lunar exploration programme, broadcast in China ahead of the “national Space Day”, held on April 24th.

As with the US-led Artemis programme, the Chinese aim to start with a short-term stay on the Moon, followed by additional missions intended to build up to a permanent presence within a research base called the International Lunar Research Station (LRS) by the end of the 2030s.

In support of this, China is operating a highly integrated development programme – the Zhōngguó Tàn Yuè (Chinese Lunar Exploration Programme (CLEP) – overseen by Wu. This combines the development and operation of on-going and future robotic mission to the Moon along with the longer-term development of crew vehicles either designed specifically for, or in support of, lunar exploration. These activities fold into them the existing orbital and soft-landing missions of Chang’e 1 through Chang’e 5, and will continue in May 2024.

It is then that China will launch Chang’e 6, a mission to investigate the topography, composition and subsurface structure of the South Pole–Aitken basin, one of the sites seen as a potential location of a future lunar base. This mission will also see an attempt to return further lunar sample to Earth – the first time samples have been returned from the Moon’s far side.

Then in 2026, Chang’e 7 will visit the same region, leaving a communication relay satellite in orbit and delivering a lander and a miniature flying probe to the surface; in 2028, Chang’e 8 is likely to deliver of a small-scale 3D printing system intended to demonstrate the use of the Moon’s regolith in the construction of a lunar base.

As well as the Chinese mission, Russia is expected to provide input to the programme as the first major partner to join with China in their lunar ambitions. This involvement is due to commence later in 2023 with the launch of the Luna 25 lander, to be followed by the Luna 26 orbiter and Luna 27 lander missions in 2027 and 2028 respectively. Russia will also provide personnel and equipment for the LRS.

Alongside of this, the China Aerospace Science and Technology Corp. (CASC) will work on crewed vehicles for transporting taikonauts to the Moon and delivering them to the surface and then back to orbit. If the plan progresses as intended, it is expected that the first phase of the International Lunar Research Station in operation by 2035 – potentially mirroring or possibly ahead of the US plans for an expanded Artemis base in the Moon’s South Polar Region.

Most recently for China has been the return to Earth of their ultra-secretive Chongfu Shiyong Shiyan Hangtian Qi (CSSHQ), an experimental spaceplane after 276 days in orbit.

Quite what the vehicle is remains unclear to western analysts – and matters have been muddled by differing statements made by Chinese authorities (some of which are doubtless intended to obfuscate matters), indicating that the vehicle is both an unscrewed cargo-carrying vehicle and a craft designed to carry a crew of 6 to orbit. However, this latter claim appears to be unrealistic; CCSHQ’s two flights have been aboard Long March 2F vehicles, which have a maximum payload capacity of 8.4 tonnes – but a vehicle capable of supporting a crew of six in orbit and returning them safely to Earth would have a mass well; perhaps as much as 20 tonnes at launch. The Chinese have also suggested the vehicle is a two-stage craft, using a scramjet engine for first stage propulsion.

The vehicle’s size approximates to that of the equally secretive X-37B spaceplane, some 8-9 metres in length and with a wingspan of between 3 and 4 metres. The May 8th return to Earth marks its second flight into space – the first being a modest 3-day flight in 2020.

The current mission commenced on August 4th, 2022, and gave rise to a lot of speculation when the vehicle deployed a small satellite, with some in the west claiming it was a  weapons platform – something China hotly denied. As it was, vehicle and cargo operated in close proximity to one another for a time, as if practicing rendezvous manoeuvres. In addition to this, CSSHQ performed more extensive manoeuvres, including altering its orbit, raising and lowering it.

The reusable test spacecraft successfully launched by our country at the Jiuquan Satellite Launch Centre successfully returned to the scheduled landing site on May 8 after flying in orbit for 276 days. The complete success of this test marks an important breakthrough in our country’s research on reusable spacecraft technology, which will provide a more convenient and inexpensive way to and from the peaceful use of space in the future.

– China Aerospace Science and Technology Corp. (CASC) statement

As with the first mission, the launch commenced from the Jiuquan Satellite Launch Centre in the Gobi Desert and while accounts vary, it appears to have concluded with the craft landing at the Lop Nur military base in Xinjiang, as it did at the end of its maiden flight.

Some in the west have been keen to play down this mission, noting that the X-37B’s first flight lasted 224 days, and its most recent – which ended in November 2022 – was908 days in length. However, the X-37B has a development history going back, and took a decade to extend its flight envelope from 224 to 908 days. CSSHQ appears to have been in development for less than a decade, and saw its mission duration leap from 4 days to 276 in just two flights – so it is hardly something to be sneezed at purely on the basis of flight duration.

Vast Contract SpaceX to Launch “World’s First Commercial Space Station”

Vast (also styling itself Vast Space), a privately held American aerospace company founded in 2021, has announced ambitious plans to launch the world’s first commercial orbital facility, Haven-1 in August 2025, and that they have engaged SpaceX to handle the launch and deliver at least one 4-person crew to the station.

“Ambitious”, because prior to February 2023, all Vast has was a mission statement (to build artificial gravity space stations), a logo and a 10,700 square metre facility in Long Beach California; outside of the founders, it did not even have employees. That changed in February with the acquisition of another start-up, Launcher, a company developing 3D printed rocket motors and an orbital transfer vehicle; this afforded Vast assets, products – but not the expertise required to build a module capable of supporting 4 people in orbit for up to 30 days at a time.

However, Vast claim they can reduce the time required to build the unit by “repurposing” elements of the automated orbital transfer vehicle. If true, this still leaves them having to ensure the 10.1 metre by 3.8 metre module is fully capable of supporting life – something which is not a priority for robotic vehicles.

In addition, the module will have deployable solar panels capable of generating up to 15 kW of electrical power, a docking module at one end suitable for capturing Crew Dragon vehicles, and around 70 cubic metres of total pressurised volume. At 14 tonnes, it is intended to be launched with all the consumables needed to support a visiting crew during their stay, with additional crews able to carry further supplies with them aboard Crew Dragon.

Exactly what Haven-1 will be used for is unclear. “Research” has been mentioned, but it also seems to be about space tourism; as a part of a deal with SpaceX, which will see the module launched on a Falcon 9 rocket, Vast have committed to one 4-person Crew Dragon launch to the module (the “Vast-1” mission), and plan to sell these seat on to interested parties, who will also have to pay for training through SpaceX. The contract also includes the option to purchase a second Crew Dragon flight in 2026.

Equally ambitious are the company’s longer-term plans. According to their website, they place to launch a much larger “Starship class” module with a diameter of 7 metres (but unspecified length) using the SpaceX Starship. This module class will then – they claim – be used to build 100-metre long “spinning stick” stations which will “provide various gravitational environments including Earth, Mars, Moon, and asteroid gravities” – although whether this is really practicable in a space just 7 metres across and spinning around its longitudinal axis is questionable at the least.

Vast claim these “spinning sticks” will be constructed over seven Starship launches apiece and support up to 40 people each, paving the way through the 2030s to a “proliferated space fleet” comprising “dozens” of stations of various types “across the solar system” in the 2040s. These, if the website is to be believed, will include units modelled on the classic “spinning wheel” stations beloved of science-fiction.

Just how well the company succeeds in these goals remains to be seen. I’m personally not holding my breath. I will give them full marks for the Haven-1 promo video, however.

Continue reading “Space Sunday: China, stations and bits” →

Japan’s first attempt at a lunar landing appears to have ended with the loss of the vehicle – once again proving that, for all its successes, spaceflight is nowhere close to being a certainty.

Launched by a SpaceX Falcon 9 in December 11^th, 2023 on a low-energy ballistic trajectory that carried it 1.4 million km from Earth before starting on its return, with the Moon getting in the way to allow the vehicle enter an extended elliptical orbit on March 20^th, 2023. Over the course of the next several weeks that orbit was circularised, allowing the vehicle to attempt a landing on April 25^th.

Essentially a private mission – the lander was built by Tokyo-based ispace – the craft was carrying a set of private and government-sponsored payloads. Among them was Rashid, a small lunar rover developed by the Mohammed bin Rashid Space Centre in the United Arab Emirates, and a “transformable lunar robot” the size of a baseball from Japan’s space agency JAXA. Other payloads include cameras and technology demonstrations.

The landing was streamed live and appeared to initially go well, the HAKUTO-R M1 vehicle having survived its extended trip to the Moon with only minor issues, all of which ispace were able to rectify.  However, during the final part of the lander’s decent – whilst it was still some 80 metres above the lunar surface, close to Atlas Crater and descending at a rate of 48 km/h, the telemetry readings for the lander appeared to switch from live data to a simulation, with no subsequent confirmation of a safe landing or any further receipt of telemetry.

ispace initially acknowledged the potential vehicle loss 25 minutes after the planned landing. It came after repeated attempts at communication had failed; six hours after that, the company issued a statement confirming they believed the vehicle had been lost.

During the lander’s final approach to the surface [the] estimated remaining propellant reached at the lower threshold and shortly afterward the descent speed rapidly increased. Based on this, it has been determined that there is a high probability that the lander eventually made a hard landing on the Moon’s surface … it has been determined that Success 9 of the Mission 1 Milestones, successfully landing on the Moon and establishing communications, is no longer achievable.

– ispace announcement on the loss of the HAKUTO-R M1 lander

Despite the loss, Takeshi Hakamada, founder and chief executive of ispace, believes the mission yielded valuable data from both the development and flight of the M1 lander. This, he said would be fed into the company’s next lander mission – M2 – which is targeting a late 2024 launch. It will carry a set of customer payloads as well as a “micro rover” that ispace developed. That rover will collect a regolith sample that will be transferred to NASA under a 2020 contract awarded to ispace’s European subsidiary.

Ingenuity Snaps Perseverance

Voyager 2 Gets Extended Mission Life

NASA engineers have developed a means to extend the science lifespan of their venerable Voyager 2 space probe beyond its already impressive 45 years – and could do the same for the Voyager 1 craft.

The twin Voyager programme vehicles, launched in August and September 1977 respectively, are the only human-made spacecraft to reach interstellar space.  Together, they are helping scientists understand the heliosphere, the protective bubble of particles and magnetic fields generated by the Sun, informing them as to its shape and its role in protecting Earth from the energetic particles and other radiation found in the interstellar environment. At the same time, the vehicles are helping those scientists also understand the nature of the environment beyond our solar system.

However, whilst powered by radioisotope thermoelectric generators (RTGs), which convert heat from decaying plutonium into electricity, the two vehicles have a limited source of power, the RTGs generating less and less electricity as the plutonium degrades.

Thus far, the flow of electricity to the science instruments has been maintained by means of turning off other systems as they’ve ceased being required – such as the high-power camera systems – and those which do not contribute to the science mission or communications. Nevertheless it has been estimated by late 2023, Voyager 2 would be unable to generate sufficient power to manage its instruments, and NASA would have to start turning them off one by one.

To avoid this, engineers carried out a review of the craft’s systems, and realised that the voltage regulation system, designed to protect the science instruments against unexpected surges in the flow of electricity to them, has a small percent of power from the vehicle RTG specifically dedicated to it; a reserve that isn’t actually required, as it also works off the primary supply. The decision has therefore been taken to release this reserve and allow the instructions access it.

This does mean that if there is a serious voltage issue on the vehicle, the regulator might not be able to deal with it – but as engineers note, after 45 years of continuous operations, the regulators on both of the Voyager craft have been perfectly stable and have never needed to draw on the reserve. While the amount of power freed-up by the move is small, it nevertheless means NASA can forestall any need to start turning off instruments until 2026.

The same approach can also be taken with Voyager 1, although the situation there is less critical at that craft lost one of its science instruments relatively early in the mission, leaving it with sufficient power to keep the remaining instruments through until the end of 2024 before decisions on releasing the power reserve needs to be taken.

Continue reading “Space Sunday: Ups and Downs” →