9

The line

"Therefore the USSR sent detailed instructions to Jodrell Bank how to find their second lunar probe, Luna 2, that was launched on 12 September 1959 and hit the moon the next day."

from a block quote in this excellent answer to the question Why did Jodrell Bank assist the Soviet Union to collect data from their spacecraft in the mid 1960's? surprised me.

Launching one day and impacting the Moon the next sounds pretty fast relative to most lunar missions.

What are the records for the fastest trips to the Moon:

  1. from launch to landing or impact?
  2. from launch to low lunar orbit insertion?

I thought about adding a third; *low lunar flyby on return trajectory" but it's a bit messy to define the time that a low lunar flyby "happened" (e.g. Luna 3) whereas impact/landing and insertion can be fairly easily identified. If you can think of a way, it would certainly be an interesting addition to the answer.

Possibly helpful:

uhoh
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    The time of closest approach to the moon would be the most natural reference for a flyby, if you really needed a tiebreaker. Loss-of-contact-behind-the-moon time might be easier to find in some cases. If you chose a milestone like "time to get within X distance of the moon", say 1000km, that would tend to put impact, LLO, and flyby missions all on the same footing, but that figure would be hard to find in most cases. – Russell Borogove Jul 17 '19 at 18:53
  • For one thing, it seems that the quoted line is inaccurate or at least misleading. Luna 2 didn't impact until 14 September, which is not the next day. – called2voyage Jul 17 '19 at 18:54
  • Though Wikipedia has this note: https://en.wikipedia.org/wiki/Luna_2#cite_note-time-4 – called2voyage Jul 17 '19 at 18:55
  • May make this tricky to answer. – called2voyage Jul 17 '19 at 18:56
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    @called2voyage NASA says On 14 September, after 33.5 hours of flight, radio signals from Luna 2 abruptly ceased, indicating it had impacted on the Moon. but I see what you mean. The question might not be so severely impacted if it turns out that Luna 2's 33.5 hours was not the record. – uhoh Jul 17 '19 at 18:57
  • @called2voyage Locating the Impact of Luna-2 on the Moon's Face at Lunar Impact (found in this answer) shows that Soviet radio observations along with those from Jodrell Bank nail down the impact time/location fairly precisely, so any problem with the duration has to be with the time of launch. – uhoh Jul 17 '19 at 19:34
  • @uhoh That site claims "Impact of the scientific pod occured at 21:02:24 GMT on September 13, followed by the impact of Block-E about 30 minutes later." which would in fact make it next-day impact and would mean the NASA date of impact is wrong. – called2voyage Jul 17 '19 at 19:42
  • @called2voyage the NASA page doesn't list any times, nor specify a time zone (except for a caveat about Moscow Time). One explanation is that the author of the NASA site is using dates the US, e.g. EST. I guess the details of the Luna 2 launch-to-impact time can't be split off as a separate question because it's intimately tied to this question. I'll pick this up again in the morning. – uhoh Jul 17 '19 at 19:51
  • Luna 1 only took 36 hours to lunar perapsis, and it would be my guess that this is by far the fastest (for [unintended] lunar flyby). Then Luna 2's impact took slightly longer at 45 hours. Comparatively LADEE and SMART-1 took the longest at 1 month / 1 month and 2 weeks respectively. Apollo's minimum was 54 hours (11) by comparison. It seems more recent missions do not use a "direct approach" and go for the maximum delta-v savings using gravity assists. Luna 1 was more like "shoot it there, hope it hits" which is a very direct, no orbit and no return plan trajectory. (sources: wikipedia) – Magic Octopus Urn Jul 18 '19 at 16:32
  • Here's the link to the wikipedia page. Also I found another article, but it isn't on my list of known and approved sources. – Magic Octopus Urn Jul 18 '19 at 16:36
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    Just noticed the timestamp on Luna 2's MET isn't matching as stated previously, so in terms of impact I do not know. In terms of fly-by/orbit I am 80% positive that it is Luna 1 after sifting through the missions on the Wiki page as almost all of them use passive adjustments like gravity assists to save delta-v. – Magic Octopus Urn Jul 18 '19 at 16:44
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    @MagicOctopusUrn perhaps somebody needs to tweet to, or instant message to or write to Jonathan McDowell to get these historical dates cleared up – uhoh Jul 18 '19 at 16:46
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    Perhaps what the quoted passage was intended to say was that the lunar impact occurred the day after the request was made. Perhaps it was already about a day after launch that the USSR issued the request, thus impact occurred "the next day". – Anthony X Aug 31 '19 at 17:23

2 Answers2

6

Luna 2 went from launch to lunar impact in 2 days 16 hours 23 minutes, according to NASA: 1959 Sept 12 06:39:42 UTC to Sept 14 23:02:23 UTC.

This was faster than any of the other Lunas, and the Rangers and Surveyors, of which only a few took less than 3 days.

More recent trips have all taken even longer. Although direct ascent used less fuel, guidance, and calculation, lunar orbit was preferred once viable it was preferable, because that gave more flexibility in choosing a landing (or even crashing) location suitable for the lander's instruments.

The original source is page 23 of Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000 by Asif A. Siddiqi, NASA, published 2002 (paper), 2017 (online). (An alternate link to this pdf is in the original question.) The relevant excerpt is copied here:

enter image description here

Much more recently, New Horizons showed that lunar orbit could be reached in just 9 hours, if some eccentric billionaire wants to take a crack at the record.
Camille Goudeseune
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  • Yep you're right. I don't know why other NASA sites are saying September 13, 1959. Maybe that's EDT rather than UTC? – Star Man Aug 30 '19 at 22:20
5

The fastest probe to land or impact on the moon was in fact Luna 2 with a duration of 2 days 16 hours 23 minutes (credit to @CamilleGoudeseune's answer).

The fastest spacecraft to successfully orbit the moon was Apollo 8 with a duration of around 2 days and 20 hours (launch to orbital insertion).

The fastest probe to do a flyby was Pioneer 4. It was within 60,000 km of the moon's surface. It took approximately 1 day and 17 hours from launch to closest approach.

You can look for other satellites and their travel times in the thorough moon.NASA.gov/exploration page Moon Missions.

uhoh
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Star Man
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