India confirms details of Vikram’s crash on Moon


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India’s government has finally officially admitted that its Vikram lunar lander crashed in September.

In a written answer to a question posed to the Department of Space in Lok Sabha, Minister of State in the Prime Minister’s Office (PMO) Jitendra Singh said the “reduction in velocity” of the Vikram lander during the final phase of its descent on the moon’s surface “was more than the designed value”. As a result, Vikram “hard-landed” on the moon “within 500 metres of the designated landing site”, he said.

…“The first phase of descent was performed nominally from an altitude of 30 km to 7.4 km above the moon surface. The velocity was reduced from 1,683 m/s to 146 m/s. During the second phase of descent, the reduction in velocity was more than the designed value. Due to this deviation, the initial conditions at the start of the fine braking phase (final phase below 7.4 km altitude) were beyond the designed parameters. As a result, Vikram hard-landed within 500 m of the designated landing site,” the minister said in a written answer in the Lok Sabha.

Except for the detail that they think Vikram landed within 500 meters of its planned landing site, this answer really doesn’t tell us much new. It was very obvious during the landing that the spacecraft was traveling too fast as it began its final braking phase, and that it then descended much too fast thereafter.

In fact, the couched language and the unwillingness so far of ISRO, India’s space agency, to provide a detailed report on the failure does not reflect well on them. This kind of cutting edge engineering requires a hard kind of intellectual honesty. They have so far not shown that kind of honesty in their response to this failure.

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5 comments

  • Gary

    I always had a difficult time getting decent velocities right when playing lunar lander simulations on a PC in the early 1980s. Hard to do in real life too.

  • dave

    “During the second phase of descent, the reduction in velocity was more than the designed value. ”

    If the _reduction_ in velocity was _more_ than intended, that means it was going too _slow_.

    And therefore, either:

    1. the onboard computer failed to compensate by re-calculating the needed burn rates and/or burn times. Or,

    2. the craft was not designed to compensate and re-calculate burn rates/times “on the fly”.

    So, yeah, like Gary said. And anyone who has played Lunar Lander knows that if you get too slow too soon, and then continue on with “normal” burn rates/times, you end up going UP, wasting your fuel, and then you run out of fuel before landing, and then crash.

  • Tom Billings

    “This kind of cutting edge engineering requires a hard kind of intellectual honesty. They have so far not shown that kind of honesty in their response to this failure.”

    This is all too typical of the Babu State in action. I had hoped India had managed to exclude such behaviors in its actual spaceflight engineering groups. It seems not.

    Of course, now that the US has its own equivalent to the Babu State, even if 2,000 years less practiced at avoiding blame, we have little room to make grand comparisons between “Deep State” and “Babu State”. In fact, Deep State seems too profound as a description. Just “American Babu State” gives a better feel for the levels of competence involved in so much of “the Resistance”.

  • Andi

    An interesting bug in the lunar landing program I tried in the ‘70s let you free fall until just above the surface and then burn all the fuel in one shot.

  • mike shupp

    Andi — I don’t know that that’s a “bug.” It might actually be a fuel saving maneuver. Rough on crew and passengers, of course.

    As for the “Babu state” …. It isn’t the old socialistic Congress Party bureaucracy that’s to blame. India’s got an increasingly autocratic state; I’m not expecting it to be more honest with the public and specific about details until Modi ceases to be the Prime Minister.

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