Major Solar Activity at the End of October
During the last week of October and the first week of November the Sun surprised scientists with exceptionally high levels of activity. It is indeed fortuitous that SORCE is available to record the present “fireworks” on the Sun.
The SORCE instruments have done a spectacular job capturing these recent flare incidents with great precision. These detailed measurements will be extremely useful to the solar physics community. For the TIM instrument, it is the first time that a TSI measuring instrument has ever seen a flare. SOLSTICE observed factors of two to ten increase in the ultraviolet while XPS recorded non-stop flare activity over many days (Oct 28, Nov 4). The SORCE scientists are thrilled to be fulfilling a dream, where instrument measurements are exceeding expectations and the Sun is cooperating by providing a most serendipitous display of unpredictable power.
From historical observations we know that the Sun moves through a cycle of activity approximately every eleven years, changing from quiet to very active conditions and then returning to its quiet state. The nature of this activity includes the appearance of both bright regions, referred to as plage or faculae, together with very dark sunspots. Both of these phenomena are a manifestation of the Sun’s magnetic field erupting from the interior and disturbing the bright surface layer of the Sun. The Sun was very active in 2001 to 2002, and it was generally felt that the Sun was well on its way back to its dormant state. Scientists were therefore quite surprised recently when new and intense magnetic activity appeared on the Sun. Indeed it is remarkable that several of the largest sunspots ever recorded appeared and moved across the solar disk during the week of October 27th.
When the Sun is active it is not unusual for intense flares and coronal mass ejections to occur. These transient phenomena carry large amounts of energy from the Sun to the Earth, and often cause havoc within our environment. The energy comes in two forms of radiation — light or electromagnetic energy that travels at the speed of light and traverses the distance from the Sun to the Earth in roughly eight minutes, and particles, primarily electrons and protons that cover the distance in roughly one day. When this transient energy reaches the Earth it interacts in quite different ways. The particles are charged and must follow the magnetic and electric fields of the Earth with a few penetrating to lower levels of our atmosphere, and causing aurora in polar regions. These particles are so energetic that they easily pass through spacecraft shielding and often damage sensitive electronics causing satellite failures. In addition, the particles and fields energize the very outer regions of our atmosphere and cause radio communication interruptions. The intense electric fields generated by the particles can also couple energy to power grids at the Earth’s surface causing disruption and power outages. (See www.sec.noaa.gov/SWN/ for more information.)
The light radiation from the flare is also very intense, but only in very energetic X-rays (XPS) and far ultraviolet (SOLSTICE), and not in the visible light that reaches the surface of the Earth (TIM). This flare radiation is entirely absorbed in the upper layers of our atmosphere where it also ionizes the atmosphere to interfere with radio communication. Moreover, the intense radiation heats the atmosphere and causes it to expand. The expansion increases the atmospheric density at all altitudes, which in turn slows satellites causing them to fall prematurely.
October 6, 2003
SORCE Continues to Make Excellent Progress
As the mission heads into its ninth month, scientists are thrilled with SORCE’s progress. The instruments continue to make excellent solar and stellar observations. Since SORCE first launched, the entire SORCE science team has met weekly to review the instrument status, spacecraft status, ground contacts, spacecraft and instrument planning, and data processing. In addition, many smaller meetings are held during the week to focus on individual instruments and the science data produced. These meetings are becoming more exciting as the instrument calibration and data processing efforts are fine-tuned.
Data are being distributed to the science community through the Goddard Space Flight Center DAAC. For additional information on obtaining SORCE data from the DAAC and reading the SORCE HDF data files, see data_access.html.
For more information, please see the SORCE newsletter for September.
September 3, 2003
SORCE Making Excellent Daily Solar Observations
Science is the word of the day. Operating in normal mode, SORCE instruments are making excellent daily solar observations, with nightly stellar observations for calibration. As the quality and quantity of solar data continues to expand, the scientists and engineers concentrate on verifying the instrument calibrations and data processing software. New experiment commands are up-loaded daily to the spacecraft.
Data are being distributed to the science community through the Goddard Space Flight Center DAAC. For additional information on obtaining SORCE data from the DAAC and reading the SORCE HDF data files, see the data access page.
For more information, please see the SORCE newsletter for August.
July 25, 2003
The days and months have flown by since SORCE was launched January 25th. We certainly have something to celebrate and be proud of! This is a great achievement and everyone is looking forward to a very long and scientifically rewarding mission.
The SORCE team is very pleased with SORCE’s progress to date and they are delighted to be on the way to meeting the mission long-term science objectives. These objectives are: 1) to extend the current 24-year record of TSI measurements, 2) to establish a data set of SSI with daily measurements over the wavelength (color) range from 1 nm to 2000 nm, and 3) to improve our understanding of the Sun’s variability and its effect on our atmosphere and climate. For more information, please see the SORCE newsletter for July.
June 26, 2003
Heading towards six months since launch, SORCE continues to make excellent daily solar observations, with nightly stellar observations for calibration. Scientists and engineers continue to verify the instrument calibrations and data processing software. As of the end of May, measurements are being validated, and some preliminary data are being distributed to the science community through the Goddard Space Flight Center DAAC. For more information, please see the SORCE newsletter for June.
May 30, 2003
As we pass four months since launch, SORCE continues to make excellent daily solar observations, with nightly stellar observations for calibration. The spacecraft is performing exceptionally well, and all instruments are operating in normal mode. Scientists and engineers are busy verifying the instrument calibrations and data processing software so the measurements can be certified valid and ready for distribution to the science community. The first results will be delivered by the end of this month. For more information see the SORCE newsletter for May.
May 2, 2003
It has been three months since SORCE was launched! SORCE continues to make excellent daily solar and stellar observations, and the solar data are received two times each day. The biggest challenge currently is the task of verifying the four instruments calibrations and data processing software, so the measurements are truly valid and ready for the science community.
The calibration process continues on all of the SORCE
instruments, which are currently operating in normal mode. The preliminary
data products generated are meticulously reviewed, and compared
to earlier instrument expectations. The data are also compared with
observations of similar instruments on other spacecrafts currently
operating. After investigating the similarities and anomalies, scientists
work towards data validation by improving data processing code.
As expected, each instrument is experiencing its own unique set of anomalies that requires further research. One step at a time, the instruments and data products are being fine-tuned to maturity, where the end result will be an accurate set of solar measurements. For more information see the SORCE newsletter for April.
March 26, 2003
Things are happening at the speed of light! Normal operations commenced on March 6 when the instruments on-board SORCE began making daily solar observations. Data are received two times each day through either the ground station at Wallops Island, Virginia or the station at Santiago, Chile.
The instruments are performing wonderfully. All instruments are in normal mode and they are collecting solar data daily. Below is a brief summary of the current status of each SORCE instrument.
TIM – Breaking ground in TSI
measurements, the TIM instrument is showing exciting promise. Scientists
are working on data processing algorithms to implement the new phase
sensitive detection method.
SIM – As a new invention, engineers and scientists are extremely pleased with SIM’s progress. Every mechanism and detector on SIM is functioning as it should, and the SIM team is currently in the midst of complex instrument calibrations.
SOLSTICE – Using the same stars for calibration purposes, the preliminary SORCE SOLSTICE results are in agreement with the UARS SOLSTICE measurements.
XPS – The first XPS measurements coming from SORCE compare very well with those of the XPS TIMED satellite measurements, which have been collected since January 2002.
March 4, 2003
All spacecraft subsystems are nominal. Over the week of February 20 - 26, thirty-three ground contacts were performed. Starting Monday, March 3, these contacts were reduced to two per day for the remainder of the 5-year SORCE mission. All science instruments are currently collecting data, and performing early orbit calibration experiments. On Thursday, March 6, these calibrations will finish and the normal operational scenarios started.
Since launch on January 25, the SORCE Mission Operations Center has routinely delivered raw telemetry data to the Goddard Space Flight Center Earth Sciences Distributed Active Archive Center (GES DAAC) for permanent archival. The SORCE science data system is now online and started generating preliminary solar data for all SORCE instruments using pre-launch calibration data. The first public release of SORCE science data will occur late May 2003.
February 14, 2003
The SORCE spacecraft and its instruments are exceeding our initial expectations, as there have been no significant glitches. 25 of the 27 mechanisms on the spacecraft have been tested and have been shown to work properly. The last 2 will be tested late in the day of February 17. 22 of 24 bus commissionings have been completed successfully and 46 of 51 instrument activities have been completed successfully. The instruments have begun taking science measurements and initial investigations of the data underway.
February 7, 2003
The SORCE MU is on and commissioning is complete for all of the instruments.
February 6, 2003
The SORCE MU is on and commissioning is complete for the TIM, SIM A and B, XPS, and SOLSTICE A instruments. SOLSTICE B commissioning began this morning (Thursday, Feb. 6).
January 29, 2003
All hardware elements are in perfect shape with no hardware anomalies of any kind being reported so far.
The spacecraft star trackers and fine sun sensor have now been powered on and we are preparing to go into normal sun pointing mode today.
We successfully powered up the instrument Microprocessor Unit (MU) and the SOLSTICE A&B instruments on 28 January and they looked great.
We are continuing to fine tune the gain, damping and limits on the Spacecraft ACS system as we optimize its on-orbit performance. This will be an ongoing activity for the next few weeks as the spacecraft commissioning continues, but overall performance is very stable and looking good.
All of the science instruments will be coming online later this week, possibly starting as soon as Thursday.
January 27, 2003
The SORCE satellite is successfully launched! The launch went exactly as planned, without a hitch. Even the weather cooperated after days of very cold weather in Florida. Spirited cheering could be heard at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado, Kennedy Space Center, NASA Goddard Space Flight Center, and Orbital Sciences Corporation as SORCE went into orbit.
Late morning the launch management team met at Kennedy Space Center (KSC) to begin the final launch procedures. The 7-person flight crew for the L-1011 started their launch take-off checklist about an hour before the aircraft carrier engines were started at 1:00 p.m. EST. The L-1011 was airborne by 2:16 p.m. EST working to reach the required 40,000-foot elevation necessary to drop the Pegasus. With the responsibility of providing live coverage of the launch, a chase plane took off shortly after the L-10ll to film the drop from behind.
The L-10ll was approximately 120 miles south-east of Cape Canaveral off the Florida coast when Mission Operations personnel said "3 - 2 - 1 - Drop" and the precious cargo was released. After dropping for approximately 5 seconds, Stage 1 of the rocket ignited. Stage 2 ignited about 90 seconds later, and Stage 3 completed the launch effort by igniting about 6 minutes after that. Spacecraft separation occurred at approximately 1:27 p.m. EST, and the first signal from SORCE came through about a minute later via a NASA tracking satellite. A high data rate contact was successful about 20 minutes later by a ground station in Hartebeesthoek, South Africa. An hour after launch everything was going smoothly - SORCE was in pointing mode, solar arrays were deployed, and all systems were working well.
January 25, 2003
All times are MST (unless otherwise indicated)
6:00 pm: After being successfully delivered into orbit by the Pegasus launch vehicle, the SORCE spacecraft continues to operate flawlessly. All planned contacts with SORCE have been successful, and spacecraft commissioning activities are proceeding as planned and on schedule. All onboard subsystems report nominal conditions.
1:27 pm: SORCE is in orbit! First contact has been made with satellite.
1:14 pm: Pegasus rocket dropped successfully.
12:23 pm: The mission status at this time is still GO, with two launch attempts possible within the launch window. The SORCE spacecraft teams at KSC and LASP continue to monitor real-time spacecraft data that is telemetered along with the Pegasus data stream.
The OCA was given the GO for takeoff at 1912 UTC time (12:12 PM MST), and the OCA takeoff went flawlessly, with 'wheels up' at 1917 UTC. SORCE engineers will continue to monitor spacecraft performance during aircraft climb to drop altitude, launch vehicle drop and launch vehicle ascent.
Meanwhile, at the Mission Operations Center at LASP, the flight operations team is preparing for acquisition of spacecraft telemetry via TDRSS. This should occur within seconds of payload separation from the Pegasus rocket. At that time, the flight operations team will continue the work done by the spacecraft launch team in monitoring spacecraft performance, including solar array deployment, which should occur approximately two minutes after separation.
12:17 pm: And we're off! The L-1011 is in the air and flying to the Pegasus drop point approximately 50 minutes away.
January 24, 2003
It's one day to launch and counting! Launch day operations at the Hot Pad begin at 7:00 am EST, Saturday, January 25th. The payload and launch vehicle support teams will assemble at 6:30 am and spacecraft power on for final checkout is expected to begin at approximately 7:15 am. All systems are "green-to-go" and only minimal monitoring activity is planned for today.
January 23, 2003
Operations to transport the integrated SORCE rocket and payload to the "hot pad" began at 4am Wednesday, January 22nd (see photos). The "hot pad", or "skid strip", is the area where the rocket is mounted to the OCA (Orbital Carrier Aircraft). Early transport was required in order to avoid heavy work-day traffic that starts to flow through the area around 6 am each morning. The convoy moved slowly taking approximately two hours to cover a distance that normally takes 10 minutes to drive when you're not towing a large rocket. Actual arrival at the hot pad was approximately 6:30 am. Shortly after arrival, as the sun was starting to peak over the horizon, activities commenced to jockey the rocket into position under the "jacked up" OCA. The remainder of the morning, and into early afternoon, was spent in integrating the rocket to the OCA and doing final preps for the flight-to-launch on Saturday. Afternoon activities included Flight Readiness Test (FRT) operations involving the spacecraft only. All test results were nominal and the spacecraft is "good-to-go" for launch. Activities planned for Thursday, January 23rd, include a Combined Systems Test (CST) which is the final test operations activity leading up to the L -8 hour "GO-NO GO" pre-launch activities on Saturday, January 25th.
January 22, 2003
Getting closer! The SORCE launch remains set for this Saturday, January 25, from Kennedy Space Center (KSC), with the launch scheduled for 3:10 p.m. Eastern Time, 1:10 p.m. Mountain Standard Time. Don’t forget you can call 303-735-3132 for information on any launch time changes.
This morning (1/22/03) was the long awaited day to transport the integrated Pegasus and spacecraft to the hot pad (see photos). Since it required closing the road, personnel will made the move very early in the morning to avoid interrupting the morning traffic. Final testing and maintenance on the spacecraft will be done from a small facility located next to the hot pad.
January 16, 2003
With the completion of the installation of the SORCE fairing (rocket
nose-cone) on Wednesday, January 16th (see
photos), the SORCE payload and launch vehicle became the "on
deck" player, ready for the next "at bat" (behind
the Shuttle), in the KSC launch lineup. Following a spectacular,
successful Shuttle launch on Thursday, January 17th, SORCE officially
moved forward as the next launch operation in the queue. Launch is
now just 9 days away (January 25th)!
Remaining launch site operations are becoming fewer with each passing day. All recent tasks have been successfully completed ahead of schedule, with no issues of note. Final preparations will commence next week with the transport of the launch vehicle/payload to the "hot pad" for mate operations with the OCA (Orbital Carrier Aircraft). The move is currently scheduled for the very early morning hours of Wednesday, January 22nd. Launch vehicle integration with the OCA is typically a half-day activity. Once the integration has been completed, a Combined Systems Test (CST) will be performed. The CST is a day-long functional verification of connectivity between ground operations test hardware and the launch vehicle. This test is run from the LSST(Launch Site Support Trailer) which has been positioned adjacent to the OCA. A final functional verification of all systems will be run as a part of the launch minus 8 hour countdown activity.
January 7, 2003
Activities on the SORCE project have picked up since the holiday break. The current launch date for the SORCE spacecraft from KSC/CCAFS (Kennedy Space Center/Cape Canaveral Air Force Station) is still holding at January 25th. On Friday, January 3rd, a test of the electrically integrated launch vehicle and spacecraft (Flt Sim 3) was successfully performed. This was the final hurdle to the actual physical marriage of the spacecraft and launch vehicle that was subsequently completed on Sunday, January 5th (see pictures). The completion of this activity was actually a "first" for the KSC Launch Support Team, as they typically do this type of integration with the launch vehicle sitting in a vertical position in a launch tower out at a launch pad. Because SORCE is an airplane drop type launch (PEGASUS), mounting of a payload to a horizontally oriented launch vehicle, in facilities normally only used for preparing payloads (spacecraft) for subsequent transport to a launch pad, was a new experience for some (this has been done repeatedly at other launch sites by the launch vehicle crew, so this was only "new" for the KSC folks). The launch vehicle and spacecraft teams are currently in the process of preparing for a post-integration electrical test (Flt Sim 4). This test is scheduled for Wednesday, January 8th, and will be the final test performed prior to installation of the fairing (nose cone) and subsequent transport of the integrated launch vehicle to the Hot Pad (three days prior to launch). Upon arriving at the Hot Pad, it's a half-day operation to mount the launch vehicle to the OCA (Orbital Carrier Aircraft-L1011). Final pre-launch activities at the Hot Pad include a combined system test (CST) that verifies connectivity between the OCA and the LSST (Launch Site Support Trailer). On launch day, pre-launch activities begin at Launch minus 8 hours and include a final checkout of spacecraft and launch vehicle functionality. These final functional test operations will be conducted from the LSST. Other recent background activities have included test link verification operations between the spacecraft and Mission Operations at LASP via supporting ground stations and the on orbit satellite system (TDRSS) that will be providing communication links to the spacecraft post-launch. A final dress rehearsal of pre- and post-launch support activities is currently being conducted from the LASP Mission Operations and Control Center (MOCC) and will conclude Thursday, January 9th. These activities involve all the folks that will be part of the team involved in early post-launch operations of the satellite.