Latest news with #DRO-B
The Star
20 hours ago
- Science
- The Star
Is China's Tiandu-1 first to enter resonant Earth-moon orbit? US raises doubts
China's Tiandu-1 satellite has entered a critical fuel-efficient orbit that synchronises with the motion of the Earth and moon, but claims that it is the first spacecraft to achieve the feat have been challenged by US and Canadian experts. The 3:1 resonant orbit – in which Tiandu-1 completes three loops of the Earth for every circuit made by the moon – is seen as a breakthrough for lunar infrastructure, including a BeiDou-like guidance system that will be needed for interplanetary exploration. Developer Deep Space Exploration Laboratory said that 'the Tiandu-1 navigation test satellite successfully carried out a key manoeuvre at perigee [the point in orbit when it is closest to Earth] on May 22 and precisely transitioned into a 3:1 Earth-moon resonant orbit'. 'This made Tiandu-1 the first spacecraft to enter a round-trip 3:1 Earth-moon resonant trajectory,' according to a statement on the website of the laboratory based in Hefei, Anhui province in central China. 'Its flight data will provide support for advancing technologies such as orbit maintenance, control, and autonomous navigation in complex gravitational environments.' Experts in the US and Canada immediately challenged the claim, pointing to Nasa's 15-year-old Interstellar Boundary Explorer (IBEX) probe that entered a near-identical orbit in 2011, where it continues to operate. Jonathan McDowell, a Harvard astronomer and space historian, and Canada-based amateur stargazer Scott Tilley both said it was debatable whether Tiandu-1 could lay claim to the title, with the IBEX craft's achievement of near 3:1 resonance. 'Yes, indeed Tiandu-1 has entered a 3:1 resonance orbit. Whether it's the first is launched in 2008 uses a similar orbit,' Tilley said. According to McDowell, the advantage of resonant orbits is that they allow a spacecraft to operate far from Earth while avoiding the unpredictable, chaotic motion caused by frequent lunar fly-bys. 'The resonance provides stability,' he said. In a 3:1 resonance, the 61kg (135lb) Tiandu-1 – which launched alongside the Queqiao-2 lunar relay satellite last year – completes each petal of its three-lobed orbit around the Earth roughly every nine days – the same amount of time it takes the moon to complete one. In April, state news agency Xinhua reported that China's DRO-B satellite had departed lunar orbit, after helping to establish the 'world's first three-satellite constellation in cislunar space', and entered an Earth-moon resonant orbit. DRO-B, a 277kg Chinese satellite that was salvaged after being stranded in the wrong orbit due to a launch mishap last year, is currently in a 3:2 Earth-moon resonant orbit, according to Tilley, who is best known for helping Nasa to find its long-lost IMAGE satellite in 2018. The Canadian amateur astronomer, who tracks satellites in his spare time, said he noticed that DRO-B had vanished from its known lunar orbit more than a month ago and began searching for it. Using graphics and research papers, Tilley modelled a 3:2 resonance orbit – one that tours the gravitational balance points between Earth and the moon known as L3, L4, and L5. After an exhaustive search, he spotted DRO-B in such an orbit. DRO-B completes three circles around Earth in the time it takes the moon to complete two. The satellite traces a broad, triangular loop with lobes near the L3, L4, and L5 points, which it swings past roughly every 18 days. 'DRO-B is not transmitting all the time like it used to, and it's likely [to be] having minor power issues as its solar panel supports were damaged during the launch mishap,' Tilley said. He added that DRO-B's orbit was especially notable because this specific class of 3:2 resonance orbit had never been used before. 'Japan's Hiten lunar probe did visit some of these points, but didn't use a 3:2 resonance orbit.' According to Tilley, China's use of these orbits seemed to be all about testing navigation-related technologies. 'Having a system that covers the entire Earth-moon system for orbital determination and positioning would be very helpful,' he said. - SOUTH CHINA MORNING POST
Yahoo
20-04-2025
- Science
- Yahoo
World's first three-satellite constellation in Earth-moon region established by China
The world's first three-satellite constellation on the distant retrograde orbit (DRO) of the Earth-Moon system has been successfully established by Chinese scientists. The development lays a foundation for the exploration and utilization of space, and for future crewed deep-space exploration. The DRO is a unique type of orbit, while the Earth-moon space refers to the region extending outward from near-Earth and near-lunar orbits, reaching a distance of up to 2 million kilometers from by scientists of the Chinese Academy of Sciences (CAS), DRO-A and DRO-B satellites have established inter-satellite measurement and communication links with DRO-L, a previously launched near-Earth orbit satellite. The achievement was disclosed at a symposium on Earth-moon space DRO exploration in Beijing on have revealed that in Earth-moon space, DRO is characterized by a prograde motion around Earth and a retrograde motion around the which provides a highly stable orbit where spacecraft require little fuel to enter and stay, also serves as a natural space hub connecting Earth, the moon, and deep offers support for space science exploration, the deployment of space infrastructure, and crewed deep-space missions. Currently, the DRO-A satellite stays in DRO, while the DRO-B satellite operates in Earth-moon space maneuver orbits, according to the Technology and Engineering Center for Space Utilization (CSU). Zhang Jun, a senior engineer at the CAS' Innovation Academy for Microsatellites, revealed that the satellites ultimately succeeded in entering their designated orbit, demonstrating China's breakthroughs in deep-space fault recovery and autonomous navigation technologies. Zhang stated that this achievement highlights the satellite team's flexibility and adaptability in complex missions and paved the way for low-cost deep-space also revealed that the project achieved the world's first spacecraft entry into DRO with low energy consumption. Through innovative design, the team completed a lunar transfer and DRO entry by using just one-fifth of the fuel usually required. Scientists revealed that the program would support China's future lunar exploration mission, including providing space-based inter-satellite measurement for rapid orbit determination and autonomous navigation services for lunar exploration mission orbiters, and supply high-precision time signals for lunar surface facilities, reported Global Times. Zhang highlighted that by using three hours of in-orbit inter-satellite measurement data, the team achieved an orbit determination precision level that would typically require two days of ground-based tracking. This advancement has significantly reduced operational costs and improved the efficiency of spacecraft in the Earth-moon space. Later, Chinese scientists will continue investigating the complex and diverse orbits in the Earth-moon space, and study the laws of the lunar space environment. With the long-term stability of DRO, scientists will carry out fundamental scientific research in such fields as quantum mechanics and atomic physics.
