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Shenzhou-21: From Launch to space station in 3.5 hours

By Gurbir Dated: November 1, 2025 Leave a Comment

Shenzhou-31 October 2025. Credit CGTN

Getting a rocket to dock with an orbiting space station is a huge challenge that requires a deep understanding of celestial mechanics. It is a little (and only a little) like Tom Cruise parachuting from an aircraft onto a moving train. The longer and slower the train, the easier the task. Yesterday’s launch of Shenzhou-21 and docking with the Tiangong Space Station was particularly tricky. A very small train moving extremely fast, but Tom did it!

Yesterday’s launch of Shenzhou-21 carrying a crew of three to the Tiangong Space Station took just over three and a half hours. Previous crewed launches took almost double that, six and a half hours.

Why was it so much quicker? What are the factors that determine the duration between launch and docking and could it be even shorter in the future?

There have now been 16 crewed launches from China’s Shenzhou spacecraft. Shenzhou-5 (15 Oct 2003) to yesterday’s (31 Oct 2025) Shenzhou-21. The first four Shenzhou missions (Shenzhou-1 to Shenzhou-4) were uncrewed test flights designed to validate spacecraft systems, orbital rendezvous, reentry, and recovery.

Typically, these trajectories have taken 1,2, or even 3 days. The concept of a “fast track” trajectory of 6.5 hours was first demonstrated in 2021 with Shenzhou-12.

  • 6 h 30 m with five orbits. A routine first employed in 2021
  • 3 h 30 m with two orbits. First used on yesterday’s Shenzhou-21 
  • 1 h 30 m with one orbit. Not yet used, but theoretically possible

    Why not always use the fast 6.5-hour or faster 3.5-hour trajectories? Surely, the quicker the crew arrive at the space station, the more efficient the mission. Getting a spacecraft from a stationary point on the surface of the Earth to dock with Tiangong at 400km, moving at 7.67 km/s, is a challenge in precision navigation, guidance, and thrust control. The shorter the trajectory, the higher the required precision.

    There are four specific attributes of a safe docking. The shorter the trajectory, the more critical each one becomes

    • Launch Window: Can be as short as a few seconds wide. If missed due to weather or unexpected range activities, a full-day launch delay would ensue.
    • Orbital Insertion: The launch vehicle’s job is to deliver the payload — here, the crew — to the precise orbit within a few meters per second of the calculated orbit. Corrections may involve missing the rendezvous point, requiring an additional earth orbit to correct.
    • Thermal and structural constraints: Short trajectories require rapid orbital manoeuvres and burns, and immediate docking manoeuvres can add unwanted stress to the propulsion system and the crew if manual override is necessary. More complex automated systems are now being deployed with greater confidence.
    • Crew stress and safety: The shorter the trajectory, the greater the demand and stress on the crew to ensure a safe ascent, orbital insertion and docking. Also, should an anomaly occur, there is a narrower window to resolve it.

    With greater testing, built-in redundancy, and higher precision in navigation, guidance and control, the CNSA has developed the required confidence to use these “fast track” trajectories for crewed flights.

    Shenzhou-21 Prior to Lunch
    Shenzhou-21 Moon above and exhust below
    Someone took the time time to calculate the camera position!
    CNSA transmit the launch live with live feeds from the launch pad, inside the launch vehicle and the Chinese Space Station showing the three tychonauts watch the launch!

    All images from the CGTN YouTube channel – Live launch of Shenzhou-21 https://www.youtube.com/live/uUNigRue9jM

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    Episode 126: Graphene: From scientific discovery to commercial application

    By Gurbir Dated: October 31, 2025 Leave a Comment

    Professor James Baker

    Professor James Baker, CEO of Graphene@Manchester, describes Manchester’s journey to commercialise the Nobel Prize-winning discovery of Graphene.

    In this conversation, recorded at the University of Manchester Graphene Engineering and Innovation Centre, Professor Baker explains the steps Manchester (the City and the University, with support from central government and foreign investors) is taking to nurture startups, SMEs and established industries in developing a commercial ecosystem centred on the applications of Graphene. He describes the unique role of the UoM, the National Graphene Institute and the GEIC.

    Some of the discussion points include

    The following summary repeats the emphasis points you requested, condensing each into approximately a 10-word sentence, supported by comprehensive citations from the source material:

    • Graphene was isolated in Manchester in 2004, and its discovery won the Nobel Prize in Physics.
    • Manchester continues its history of innovation, fulfilling the “discovered in Britain” vision.
    • Extraordinary properties (e.g., 200 times stronger than steel) drive an industry “pull” philosophy.
    • Commercial applications include batteries, sensors, coatings, composites, and sustainable construction materials.
    • The National Graphene Institute (NGI) focuses on accelerating fundamental 2D material science with low Technology Readiness Level (TRL).
    • The GEIC is “industry-led but academic-fed,” accelerating high TRL commercialisation with know-how.
    • The Manchester Model (NGI/GEIC) helps companies navigate and accelerate through the “valley of death”.
    • The GEIC has fostered over 70 startups, many of which are now scaling up and opening factories.

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    Episode 125: Britian’s Greatest Pilot Captain Eric “Winkle” Brown

    By Gurbir Dated: September 4, 2025 Leave a Comment

    Captain Eric “Winkle” Brown. January 2011

    You may have seen the BBC documentary Britain’s Greatest Pilot. Yes, he was an outstanding pilot, but there was much more to him than just that. I published extracts from an interview with Captain Eric Brown in April 2011. This extended version (over an hour) has not been published before .. until now.

    In 2011 I visited Captain Eric Winkle Brown to record an interview on his one-to-one meeting with Yuri Gagarin on 13th July 1961 at the Admiralty in London. This was the day after Gagarin visited Manchester. After that discussion, the interview continued. Captain Brown spoke of his fond memories of a German WW1 pilot, Ernst Udet, who encouraged him to fly. During the war, he excelled as a test pilot and went on to become the chief test pilot at Farnborough.

    After WW2, using his fluent German language skills, he interrogated Hermann Goering, Hanna Reitsch and Wernher von Braun. He spoke of a mission to Germany immediately after the war to acquire German aviation technology. Following a secret UK/USA deal, Britain passed its research on supersonic aviation to the USA and cancelled the Miles M.52 program. Had this deal not gone ahead, Eric Brown would have been the first to break the sound barrier in 1946; instead, Chuck Yeager claimed that record in 1947. He recalls that and many other stories in the interview recorded in his home in January 2011.

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    Breakthrough Initiative – A Decade On

    By Gurbir Dated: August 31, 2025 Leave a Comment

    Pricipium Issue 50. August 2025

    A version of this article was first published in August 20205 issue of Pricipium, the quarterly publication from the Initiative for Interstellar Studies. You can download the full issue here without charge.

    The audio interview on which this piece is based (episode 122) is available for download here.


    On 14 October 1959, a spacecraft, Luna 2, impacted the Lunar surface close to Mare Imbrium. It was launched by the USSR and arrived on the Moon two days after launch. It is the first object made on Earth to travel to the surface of another world. A decade later, spacecraft from Earth arrived on Venus and Mars. In the 21st century, spacecraft have arrived on the surface of Titan, asteroids, and even a comet. Five spacecraft have left or are on a trajectory to leave the solar system. In one lifetime, Interplanetary exploration has become almost routine. But where are we on our quest for interstellar exploration?

    So far, exploration of the Solar system has been within the purview of national governments, predominantly the USA and the Russian Federation (formerly the USSR), as well as the European Space Agency and the Japanese Space Agency, in the case of Cassini-Huygens and Hayabusa. Interstellar exploration is many orders of magnitude more challenging. The immense challenges of interstellar exploration include vast distances, technological innovations, enormous timescales, and a novel funding source. Could the Starshot Initiative from the Breakthrough Foundation be the solution?

    The Breakthrough Initiatives are the brainchild of physicist, entrepreneur, and investor Yuri Milner.

    Breakthrough Starshot is a $100 million research and engineering program aimed at demonstrating the proof of concept for new technology, enabling ultra-light, uncrewed spaceflight at 20% of the speed of light and laying the foundations for a flyby mission to Alpha Centauri within a generation. The Starshot initiative, a proof-of-concept launched by Yuri Milner and Stephen Hawking in 2016, is funded by the foundation established by Yuri and Julia Milner.

    Milner identified the discrepancy between the outstanding scientific question of our time, Life in the Universe. But he says, “On the bright side, that means it could offer considerable scientific return on investment”.

    Initiated in 2012, the Breakthrough Prizes are a set of annual international awards in the fields of Mathematics, Life Sciences, and Fundamental Physics. The awards are part of the “Breakthrough initiatives” founded by Yuri Milner and his wife, Julia Milner. Laureates receive $3 million each in prize money (funded by Yuri and Julia Milner and others, including Sergey Brin and Mark Zuckerberg) during a televised award ceremony designed to celebrate their achievements and inspire the next generation of scientists. Breakthrough Prize was the first and is now joined by Breakthrough Listen, Breakthrough Watch, Breakthrough Message and Breakthrough Starshot.

    Breakthrough Listen is targeting the 1,000,000 closest stars to Earth and is the largest-ever scientific research program seeking evidence of civilisations beyond Earth. The radio and optical surveys will cover a larger portion of the sky, deploy more instruments in multiple locations, have higher sensitivity, and utilise state-of-the-art digital signal processing and artificial intelligence tools.

    Breakthrough Watch is a program to look for Earth-like planets within 20 light-years away, starting with the nearest Alpha Centauri system. If life exists on these planets with Earth-like characteristics (in terms of temperature, pressure, rocky surface, and potentially water), then the tell-tale signs of biosignatures and techno-signatures could make that breakthrough and detect the very first unambiguous signs of extraterrestrial life.

    Breakthrough Message is an initiative designed to address the question: if the existence and the whereabouts of the first extraterrestrial intelligent civilisation is finally confirmed, what do we say to them? The content of the message is the primary focus, but so are the questions of who decides what form (language) the message will take, how it is constructed and who will send it. As the Apollo 8 astronauts recalled following their 1968 trip to the Moon, “We set out to explore the moon and instead discovered the Earth”. This is perhaps the most profound of all the initiatives, as it will allow us to learn about ourselves – even if no message is ever sent.

    These initiatives can inform and complement one another. Results from Watch and/or Listen may direct Starshot and message.

    Dr Pete Worden chairs the Breakthrough Discuss conferences and actively discusses the themes of all the Breakthrough initiatives, emphasising their interdisciplinary nature and focus on fundamental questions about life and intelligence. His interest in space and astronomy started as a boy when he asked his mother, “’Okay, what do people do that study stars?’ And she called them astronomers”.

    Pete Worden had a long, distinguished career with a background in the military, specifically working with the Air Force, Space Command, missile defence, and being instrumental in the responsive space program during his active duty. He worked on arms reduction with the USSR during the Cold War.

    In around 1982, long after the Apollo program, Pete Worden applied unsuccessfully to NASA’s astronaut program. During his time as the director of Ames Research Centre, he met Apollo 15 Command Module Pilot Al Worden. Both came from Michigan and were able to determine that Al Worden’s family was part of the extended Warden family in Michigan that had adopted Pete Worden’s grandfather.

    In 2015, he left as head of NASA AMES Research Centre to become the chairman of the Breakthrough Foundation. In this role, he provides strategic leadership and oversight of the Breakthrough Initiatives suite. Reflecting on his 2015 meeting with Yuri Milner, he recalls, “he asked me to be the chairman of the overall farm foundation, not just the executive director of the initiatives, and so we’ve been at it about 10 years, and I think we’ve made major accomplishments”.

    In his 2021 publication “Eureka Manifesto”, Yuri Milner asserts that “unlike organisations, businesses, companies or even nations, human civilisation can be seen as an entity that lacks a common mission. In the absence of that vision, humanity hinders its collective progress and, thus, in the end, its potential for long-term survival”. However, he does not simply assert his views as words on a page; by funding a series of apolitical, multidisciplinary, and international initiatives, he hopes to make progress on the most challenging questions of our time.

    Reflecting on the big question at the root of all the initiatives, Worden says, “I think we’re going to find pretty strong evidence of life within a decade. Probably with our own solar system… so I think we’ll find life within a decade…. but I’m virtually certain we’re going to find life everywhere within a decade”. On the “whether we find evidence of intelligent life that’s .. who knows. You know, and again it depends on what we mean by intelligence..”

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