domingo, 12 de junio de 2011

Proof! Bio Station Alpha is Just an Image Artifact (Video)

The streak on Google Mars misinterpreted as a secret Mars base.
It’s time for another episode of “Conspiracy Theory of the Week.” This one involves a supposed secret space station on Mars. The You Tube video showing “Bio Station Alpha” (below) went viral and was even reported on some mainstream media outlets. The station is supposedly a 700 ft x 150 ft structure on Mars and by some accounts is colored white with blue and red stripes. It was found on Google Mars by an “armchair astronaut” and breathless conspiracy bloggers have touted this as the most important discovery on Mars yet, and “proof!” that NASA is hiding their activities.

In reality, this is not a space station, a Mars base or any type of structure – created or natural — on the surface of the Red Planet. What shows up in this location on Google Mars is just a smattering of about 11 bad pixels from data dropout – a linear streak artifact likely caused by a cosmic ray hitting the Mars Express spacecraft while it was taking the image – and then that smudge has been badly distorted through image processing when it became part of Google Mars.

“This looks like a cosmic ray hit,” said Tanya Harrison, planetary scientist on the science operations team for the Mars Reconnaissance Orbiter Context Camera (CTX) and Mars Color Imager (MARCI) at Malin Space Science Systems. “We see these from time to time in the MARCI data from MRO.”
Here’s the image that is seen on Google Mars after processing, which includes very noticeable compression artifacts:
And now here’s the original image taken by the Mars Express High Resolution Stereo Camera image (H5620_0000_ND), taken on May 18, 2008 (and here’s the link to the original image):
Original Mars Express HRSC image of the location in question on Mars. Credit: ESA
This image really makes it clear this is an image artifact from a cosmic ray hit.
Here’s the same location taken by the MRO Context Camera (CTX) on January 25, 2010 (a crop of the same location as seen above from the original large CTX image, available here):
MRO's Context Camera (CTX) image MRO CTX B17_016407_2528_XN_72N029W of the same location. Credit: MSSS
In this image, each pixel represents a distance of about 6.25 meters, a higher resolution than what is available from the Mars Express spacecraft, which takes images at 10 meters per pixel. Obviously, there is no structure or anything unusual at that location, except for the northern polar sand dunes.
Harrison explained that the CTX acquires grayscale (black & white) images at 6 meters per pixel scale over a swath 30 kilometers wide and provides context images for the MRO HiRISE and CRISM cameras, which can take even higher resolution images. It is used to monitor changes occurring on the planet, and help the science team select critical science targets. The team at Malin Space Science Systems pores over the images looking for anything unusual. In this case, at this location, they found nothing.
“Every day, the images we acquired with CTX and MARCI the previous day are inspected by multiple sets of eyes,” Harrison told Universe Today. “We look at every single image for multiple reasons: checking the health of the instrument, monitoring weather conditions for future targeting of the cameras, and looking for anything geologically interesting.”
Harrison added that nearly all the operations folks on the team have Master’s degrees or Ph.D.s in geology or a related field.
“If we spot anything out of the ordinary, we look at previous images of the area, not just from CTX and MARCI, but from the Mars Global Survery’s Mars Orbiter Camera, the THEMIS VIS and IR on the Mars Odyssey spacecraft, the HRSC on Mars Express, and Viking,” Harrison said. “This lets us look at the features at different illumination angles, times of day, resolutions, etc. We know better than to speculate on something below the resolution of our cameras, so if we see something in CTX that’s worth following up on at a higher resolution, we ask HiRISE to shoot it. The same thing was true for MOC, following up on things observed in the low-resolution wide angle images with high-resolution narrow angle images.”
Clearly, this region has been imaged and examined previously, with absolutely nothing found by the top experts in the field. The region is so uninteresting that no one has requested for HiRISE — which can take images of 1-2 meters per pixel — to take any images of this area.
Harrison said CTX takes images of Mars that are up to 30 km wide and over 300 km long at a very high resolution. “This is a pretty big footprint with a relatively high resolution compared to previous cameras!” she said. “The size of that footprint has allowed us to cover over 60% of Mars at 6 meters per pixel in the 5 years MRO has been orbiting Mars. In addition to mapping, we use CTX to acquire stereo coverage of key areas, as well as to monitor hundreds of locations on Mars for changes such as new impact craters and dust activity.”
If there were something unusual on Mars, the people at NASA, ESA, MSSS and anyone monitoring Mars would have imaged this site repeatedly with the best cameras available. They would love to find something unusual, groundbreaking and front-page worthy, and if they did would be shouting it from the rooftops, not hiding it.
You can hear Harrison talk about how the images taken by the various Mars orbiters require meticulous planning, on the June 1, 2011 episode of 365 Days of Astronomy.
MSSS is comprised of several small groups which all contribute to designing, building, and operating cameras on orbiters and rovers at other planets.
If you want to see the image artifact on Google Mars, here are the coordinates: 71 49’19.73?N 29 33’06.53?W
And, if you must, here’s the video by David Martinez: