Boulder Field at Tranquility Base?

[rogerinnh]

When Neil Armstring was flying the Lunar Excursion Module to Tranquility Base he came very close to using all the available fuel as he looked for an appropriate landing spot. Later, he would state that the intended landing spot was a "field of boulders" so he had to fly past it and set down in a better location. Yet, all of the photographs from the Apollo 11 landing site show a vast, very flat, landscape. I know that the horizon is a lot closer on the Moon than it is on Earth, but he could actually have flown many miles past that boulder field in the few seconds of additional flight? Are there any subsequent photos from orbit that actually show a boulder field anywhere near where the Eagle landed?

 

[vogon13]

I seem to recall seeing a photo of the boulder field. Might have been a subsequent mission that photographed the landing site. Sorry can't cite a reference, but will check my big 'coffee table' book on Apollo missions.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[vogon13]

OK, did some checking, and it appears the problem was noted after the LM descended below 3000 feet. The problem was a crater strewn with boulders, and more boulders lying on the surface around it. Armstrong elected to continue on downrange till he cleared the problem.<br /><br />From his height, the crater must not have been very big, and I am reading into this that the downrange manuever was not that big.<br /><br />This implies they landed fairly close to it. Also, after landing, many craters from 1 to 30 feet in diameter were visible through the LM windows. It is possible, the specific crater at that point would have been 'amongst its' brethren' and not specifically recognizable.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[najab]

Remember that a boulder bigger than about 3-4 feet across would be enough to ruin everyone's day but stuff that small wouldn't be visible from on-orbit imagery, and would easily be hidden by undulations in the terrain.

 

[bushuser]

I seem to recall that the Eagle was significantly downrange from the planned landing point...the boulderfield was not what Neil & Buzz had trained for. This occurred because during undocking of the LM, extra velocity was imparted by springs in the docking mechanism, and no one had accounted for this in the trajectory calculations.

 

[najab]

><i>This occurred because during undocking of the LM, extra velocity was imparted by springs in the docking mechanism...</i><p>If memory serves correctly, it wasn't springs that imparted the extra velocity, it was that they didn't fully depressurise the tunnel before undocking and the outgassing at undocking gave them an extra few feet per second.</p>