Monday, April 20, 2015

Four NEOSSat Images in Search of Respect

          By Chuck Black

The Canadian Space Agency (CSA) has released a series of four images taken by the Near-Earth Object Surveillance Satellite (NEOSSat) in early 2015. The released images provide a strong indication that initial difficulties relating to the roll out of the satellite during the 2013 - 2014 period are finally being overcome.

"Raw" low-res NEOSSat image of Orion Nebula. NEOSSat is a Canadian micro-satellite which uses a 15 cm aperture f/5.88 Maksutov telescope similar to the one used on the MOST spacecraft. It's stabilized on 3-axis and has a pointing stability of ~2 arc seconds in a ~100 second exposure. Image c/o CSA.

According to Microsat Systems Canada Inc. (MSCI) director of micro-satellite programs Ross Gillett, the images have been deemed by the CSA to be suitable to release "for educational purposes," and are expected to eventually end up in university level academic presentations related to NEOSSat operations and the various technologies and techniques used to assess and study space derived images.

This is because the released images are "raw," monochrome, and exhibit small black flecks indicative of damaged charge-coupled device (CCD) pixels, (which are understood to be from radiation and aging), saturation from bright objects, and other artifacts that are normally removed from satellite imagery before public release through a process of clean up and flat-field correction techniques. 

"Raw" NEOSsat image of M33 galaxy. Image c/o CSA.
NEOSSat image clarity is also limited by the performance of the CCD itself, which spreads some of each pixel signal to the adjacent pixels and softens image clarity. This is commonly done with CCD's to more closely reproduce the look obtained with a traditional optical telescope.

Of course, flat field correction is a standard calibration procedure used on CCD images in everything from pocket digital cameras to the Hubble Space Telescope. Corrected NEOSSat images could reasonably be expected to be of a far higher quality and utility.

NEOSSat images could also be coloured using well understood technologies such as satellite or ground based filter wheels and other methodologies, which are normally standard procedure for use on Hubble, other satellite derived images and even the images derived from ground based telescopes. 

According to Gillett, NEOSSat optical performance is very close to its "diffraction-limit," or as good as its 15 cm aperture size could ever permit, which is a testament to the skills and capabilities of the NEOSsat project team. NEOSSat also achieves better pointing stability than the earlier MOST space telescope. MOST is capable of about 1 arc second accuracy whereas NEOSSat is able to achieve 0.5 arc second accuracy.

MSCI, which recently took over the operations of the Microvariability and Oscillation of STars (MOST) micro-satellite (as outlined in the April 15th, 2015 post, "The MOST Space Telescope Joins the Private Sector") is also the prime contractor for NEOSSat.

"Raw" NEOSsat image of M2 cluster. Image c/o CSA.
But MSCI's primary challenge, and NEOSSat's main role, has always been to detect and identify near-Earth asteroids, satellites and debris orbiting the planet, which are activities normally requiring a higher degree of control over the direction in which the NEOSSat telescope gets pointed than is necessary for stellar imaging.

And, as outlined in both the July 7th, 2014 post, "NEOSSat Not Up to the Job; Government Report Blames Contractor," and the July 28th, 2014 follow-up, "Customers vs Project Managers: The Real Truth about NEOSSat," there was initially much concern over whether the satellite would ever be able to fulfill its primary mission.

However, it's quite possible that NEOSsat has also recently been tracking asteroids with success. A second series of so far unreleased NEOSSat images, (likely taken during the tracking of the January 26th, 2015 close approach of asteroid 2004 BL86 to within approximately 1,2Mln km of the Earth), is rumored to be noteworthy, if only because it purports to exhibit the superb pointing stability (0.5 arc seconds, or 1/7200 degree) that NEOSsat is required to achieve operationally as per its designed specifications.

So has NEOSSat overcome its initial difficulties to achieve its mandated operational capabilities?

According to Gillett, the CSA has already formally declared NEOSSat as compliant to its specified performance for both the planned Defense Research and Development Canada (DRDC) high Earth orbit surveillance system (HEOSS) mission to monitor orbiting satellites and space junk and the University of Calgary near Earth space surveillance (NESS) mission to detect and track asteroids. 

However, no one at the CSA seems currently willing to go on record to confirm this. Look for that to change over the next few months as data from the program slowly begins to trickle out into academia.

"Raw" NEOSSat image of the Horsehead Nebula. According to the MSCI website, the micro-satellite is designed to "detect and identify near-Earth asteroids and to track satellites and debris in Earth’s orbit." The principal investigators are Dr. Alan Hildebrand at the University of Calgary and Dr. Brad Wallace of DRDC. Image c/o CSA.


  1. Good news. I know the DRDC team is more excited about NEOSSat progress than CSA is so any positive news coming from the agency is good to see - even if it's grudgingly given. What gets lost in discussions on NEOSSat is that it's largely an experimental mission to explore microsatellite capabilities and techniques. For DRDC, at least, one of the stated objectives was to explore joint project relationships with CSA.

    The opening paragraph of the blog mis-identifies NEOSSat as MOST,

  2. Thanks for the feedback, Frank.

    The error in the opening paragraph has been corrected.

  3. MOST achieves pointing of better than 1 arcsec 99% rms, not 2 arcsec. NEOSSat does have better pointing performance, but by a factor of 2, not 4, over MOST.

  4. Thanks for the correction Jaymie. The numbers I used were supplied by MSCI.


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