Is “Asteroid 2004 MN4” A 1960s-Era Booster Stage?

Some of you may have seen the news story on Friday, December 24, about the asteroid “2004 MN4” which said that it has a greater than 1% chance of colliding
with the Earth in 2029. It was rated Level 4 (out of 10) on the
“Torino Scale”, a state of alert which had never been reached before. I used an online orbit simulation at a NASA web site to look at this.
(I’m not an astronomer so I don’t know those calculations myself.) I ran
it backwards to look for previous encounters with Earth. I found one around April 16-19, 1967. That coincides with the April 17, 1967, launch
of NASA’s Surveyor 3 lunar probe. I posted more info on my personal web site. So that adds a possibility that 2004 MN4 could be a leftover rocket body
from Surveyor 3. If anyone knows astronomers who are working on 2004 MN4, please send this
along and make sure this is included among possibilities they’re considering.

2 thoughts on “Is “Asteroid 2004 MN4” A 1960s-Era Booster Stage?”

  1. The story was updated between the time it was submitted and posted on SciScoop. I took Surveyor 3 out of the title since it’s now a list of possible candidates. The original URL will still work and will redirect you to the new page.

    NASA JPL responded. So it isn’t necessary to ask astronomers to make sure they’re keeping open to the possibility of a rocket booster. They confirmed that they’re considering that, and that the orbit does look like one where a booster could have gone. So now that we know they won’t miss this possibility, let’s wait and see what they come up with.

    Also, with updated computations on the orbit, NASA’s Surveyor 3 from Apr 1967 is off the candidate list now. NASA’s Ranger 6 from Feb 1965 is the closest match.

    See also NASA JPL’s 2004 MN4 impact risk page.

  2. I note that it is likely that the brightness is a significant factor in measuring the size. A bright white object may reflect as much light as a larger and darker rock.

    If this is a booster, the large size estimate implies that it is still a bright object. So it probably still has a lot of white paint on it. I wonder if the spectrum of a white booster would look significantly different from that of a rock and whether the spectrum can be measured on such an object.

    I suspect the people working on 2004 MN4 already thought of this. But I thought my thinking out loud might amuse you, reader.

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