DAILY WATCH
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Anomaly approaching sun from June 23, C3 |
TODAY'S SPACE WEATHER
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SOHO
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(Summary of prior day)
Major Magnetic Storm - 6.26.98
During the night the electron levels began fluxing very heavily, and the planetary magnetism [PK] values rose quite suddenly from active readings of around "3" to major level magnetic storm readings of "6" and "7."
The readings remained in the "red" storm levels for nine consecutive hours and a derived Magnetic-A Index of greater than 30 had already been observed as of 0900 UTC this morning.
This qualifies as a major level magnetic storm, and is particularly interesting because of the lack of a forecast or magnetic storm watch from the SEC and NASA for such an event to occur... much like a couple months ago when we had several unforecasted and unexpected major to severe magnetic storms.
Here is the URL for the PK readings...
http://www.sel.noaa.gov/planetary_k.html
25-Jun-1998 (ESR)
No telemetry ofter 04:43 UT
ESR at 02:35 UT, 04:38 UT
24-Jun-1998 (C1-C2-C3-EIT synoptic; TM Submode 5-6; LASCO doors closed; ESR)
SOHO spacecraft emergency declared at 23:30 UT
ESR at 23:16 UT
All 3 LASCO doors closed 12:31-12:45 UT for momentum mgt. maneuver
TM Submode 6-to-5 transition at approx. 12:30 UT
forwarded Message:
Subj: SOHO Spacecraft Observations Interrupted
Date: 98-06-26 10:26:40 EDT
From: NASANews@hq.nasa.gov
Sender: owner-press-release@lists.hq.nasa.gov
Don Savage
Headquarters, Washington, DC
June 26, 1998
(Phone: 202/358-1727)
Bill Steigerwald
Goddard Space Flight Center, Greenbelt, MD
(Phone: 301/286-5017)
Franco Bonacina
European Space Agency Headquarters, Paris, France
(Phone: 33-1-5369-7713)
RELEASE: 98-112
SOHO SPACECRAFT OBSERVATIONS INTERRUPTED
Ground controllers lost contact with the NASA/European Space Agency (ESA) Solar and Heliospheric Observatory (SOHO) spacecraft June 24 during maintenance operations.
SOHO went into emergency sun reacquisition mode, and ground controllers lost contact with the spacecraft at 7:16 p.m. EDT on June 24. This mode is activated when an anomaly occurs and the spacecraft loses its orientation toward the Sun. When this happens, the spacecraft automatically tries to point itself toward the Sun again by firing its attitude control thrusters under the guidance of an onboard Sun sensor.
Efforts to re-establish contact with SOHO did not succeed and telemetry was lost. Subsequent attempts using the full NASA Deep Space Network capabilities have so far also not been successful.
Engineers from NASA and ESA are attempting to reestablish contact with the spacecraft.
SOHO is a joint mission of the European Space Agency and NASA. It was launched aboard an Atlas IIAS rocket from Cape Canaveral Air Station, FL, on Dec. 2, 1995, and mission operations are directed from NASA's Goddard Space Flight Center, Greenbelt, MD.
In April 1998, SOHO successfully completed its nominal two-year mission to study the Sun's atmosphere, surface and interior. Major science highlights include the detection of rivers of plasma beneath the surface of the Sun; the discovery of a magnetic "carpet" on the solar surface that seems to account for a substantial part of the energy that is needed to cause the very high temperature of the corona, the Sun's outermost layer; the first detection of flare-induced solar quakes; the discovery of more than 50 sungrazing comets; the most detailed view to date of the solar atmosphere; and spectacular images and movies of coronal mass ejections, which are being used to improve the ability to forecast space weather.
More information and images from SOHO can be found on the Internet at:
http://sohowww.nascom.nasa.gov/
- end -
IMPACT
What happened to the SOHO craft?
Date: 98-06-26 17:11:06 EDT
The SOHO Solar observing spacecraft remains out of commission and it is becoming more apparent as time goes by that the chances of regaining control and communications with the observer are diminishing. According to the information released by NASA and the SEC, an anomaly impacted the SOHO craft early on June 24th causing it to lose proper alignment to the Sun, as well as communications with Earth. Normally, when this occurs the craft will use stabilizing boosters onboard and a solar alignment sensor to realign itself to a proper view of the Sun.
This time, the craft has not righted itself nor have communication been reestablished. NASA has tried the normal communications methods, as well as their deep space network... both without success.
If this becomes a permanent situation, it represents a tremendous loss in the observation and forecast sciences related to the Sun. The SOHO had become invaluable in multi-spectrum observations of the solar disk with amazingly detailed images of spots, flares, CMEs, and filament ejections... as well as the discovery of over 50 sun-grazing comets including three recent ones, two of which impacted the Sun last month.
If the craft is indeed lost, it would represent a technology setback of over a decade in solar-terrestrial research... coming at the worst possible time, with the next three years being the main build up to the expected Solar Maximum in 2001.
What caused this?
There are of course a number of possibilities for the loss of communications and alignment of SOHO. The most likely are:
1) Impact from a solar event or related energy cloud.
2) Impact from a physical object [meteor, asteroid, cometary debris]
One piece of evidence in favor of cause #1 is the strong magnetic storm we have experienced starting last night. The SOHO is positioned roughly halfway between the Earth and the Sun. At that distance, energetic events originating on the Sun would impact SOHO in half the time they would require to reach Earth. Generally speaking, when a eruptive flare, or CME occurs on the Sun it takes about 72 hours [on average] for the energy cloud to reach Earth... this means it would be around 36 hours after it impacted the location of the SOHO craft. The anomaly is said to have affected SOHO early on the 24th... and 36 hours later [last night] we saw a sudden and unexpected major magnetic storm event impact Earth's magnetosphere. The timing could of course be a coincidence, but it does match up with the event that caused our magnetic storm having been in the vicinity of the SOHO craft at around the time of the malfunction.
Aside from the ongoing threat of micro-meteors striking our satellites or other spacecraft, there have been a number of news stories in the past couple of weeks regarding small meteors striking Earth. This could indicate we are in a general region of micro-meteors or other cometary debris. Even a small meteor storm [grain of sand sized particles] would be capable of disabling a spacecraft if sufficiently dense and directed just right... this is the threat we have heard about with the expected Leonid meteor storms this November and again in November of 1999.
Just How Blind Are We?
We are not totally blind without the SOHO craft, but it is a tremendous loss of image data in various spectrums. We still have a number of solar observing stations [telescopes] here on Earth, as well as the Japanese space telescope [Yokhoh] of which I have occasionally sent out images from. However, these instruments are of no where near the same quality and real-time nature as the SOHO... especially for monitoring and forecasting ejections and flares.
We also have other space craft such as the ACE, which are in position and designed to measure the energetic particles streaming toward us from the Sun. These are designed to give us a very short-term "heads up" of an approaching solar storm event. This would be equivalent to relying on wind instruments on ocean buoys to sense an approaching hurricane, but not having the real-time satellite data to observe the storm's development and movement in detail from space.
When Will We Know?
That's a question that is hard to answer. NASA and the European Space Agency are attempting on an ongoing basis to reestablish communications with SOHO, and will for some time to come because of the value of its instruments and data, and the seriousness of the loss of that data with the approaching Solar Maximum. IAM not sure when they will officially declare that it is a lost cause. All we can do is hope and wait for word. There is certainly still a chance they will be able to reestablish a link to SOHO and that the craft can right it's position to resume observations. One thing is for certain, without SOHO we can expect there to be many more unobserved solar events that could impact Earth with little or no advanced warning.
WORLD
QUAKE DATA CENTER
QUAKE DATA
ANIMATIONS
HAVE WE
REALLY FIGURED OUT WHAT THE SUN IS?
One of the biggest embarrassments of 20th-century science -- the sun's refusal to emit nearly as many neutrinos as physicists say it should -- inched closer to a possible solution last week when experimenters reported strong new evidence that these weird elementary particles, long thought to be perfectly mass-less, may have a small amount of heft after all. If neutrinos indeed have mass, the story goes, they can change "flavor" on their flight from the center of the Sun, eluding the electronic snares earthlings have been setting. The neutrinos wouldn't be missing, but traveling in disguise. continue
SOHO
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