NASAOne of NASA’s flagship projects in cooperation with ESA is called SOHO, which stands for Solar and Heliospheric Observatory. NASA, being a US government agency, reports through SOHO observations on the behavior of the Sun amongst other things. Since recently the solar activity has intensified significantly after a long period of low to very low activity without solar flares. LASCO 1 and 2 are telescopes recording those events on the Sun which then impact Earth directly through magnetic storms and other means. On July 18, 2009 excessive activity took place with some of the largest solar flares measured in recent days and months. Strangely enough, SOHO’s lacking to report just on this day, raises more than a few questions. This is where researchers such as Rick McLastname dig in and get to the bottom of the anomalies.

Here you find the search page on the SOHO site that usually shows the daily observations, yet not on July 18, 2009… http://sohodata.nascom.nasa.gov/cgi-bin/data_query:

LASCO data missing 18-JUL-09

These are some simplified observations from Rick, after he communicated with a NASA representative who gave the ‘official’ story:

1) The first day of missing LASCO images was because the thrusters on the satellite were fired to correct it’s orbit/course. They closed the doors around the LASCO instruments as to prevent contamination with Hydrazine.

2) They (NASA) don’t know what the odd objects that we’ve been seeing are. I don’t think it’s dust particle – it’s something else orbiting the Sun. Mr. V has analyzed the orbit and deduced that it is similar to the SOHO orbit around the LaGrange point (but at a different attitude, suggesting it’s one of our probes)

3) The Magnetometer instruments went down for some odd reason, and SOHO is in a position where the high gain antenna is not pointed at Earth (this happens from time to time) and they can’t access the onboard systems to correct the problem. Doesn’t mention what caused the problem though. I might be able to infer it if I was a spacecraft scientist, but I’m not.

This was the official response from NASA on the missing LASCO data:

“On 20090718 the LASCO doors were closed in preparation of the station keeping maneuver on 20090719: http://sohowww.nascom.nasa.gov/hotshots/2004_01_04/
Station keeping maneuvers involve thruster firings, and the LASCO optics must be protected against contamination by hydrazine.”

Here is the response to Rick’s question about anomalous objects in LASCO images, such as the one below on July 20, 2009:

LASCO image 20-JUL-09

“No, don’t have a good estimate of the distance of the debris in the image of 20090720. I also think that it is rather close, though. I suspect it is a dust particle close to the spacecraft, possibly released during the various door openings earlier that day (CDS, UVCS, LASCO). The multi-layer insulation (MLI), which is wrapped around the spacecraft and most instruments has probably become a little “flaky” after over 13 years in orbit.“

And the answer to Rick’s last question regarding the recent lack of MDI images:

“MDI has a technical problem with its Image Processor. Unfortunately, as we are currently in a “keyhole” http://sohowww.nascom.nasa.gov/hotshots/2004_01_04/, our DSN contacts with the spacecraft are very limited. A lot of patches, tables, etc. need to be re-loaded and due to the keyhole that is expected to take days. I hope that MDI can be returned to science mode towards the end of the week.”

When we asked Rick what his thoughts were about the ‘dust particle’ explanation, he answered: “Well I’m confused myself, as the satellite is assembled in a clean room, so there shouldn’t be any dust at all. When the doors were closed/opened, if a particle was released it shouldn’t have that downward trajectory…“

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Filed under: 2012 • Safety Tips 2012 • Solar Maximum 2012

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