03.14.10 - Trim Motor Firing #2 was successfully completed this morning. This was different from our previous burns in being a perigee burn to raise apogee. The final orbit trim maneuver, TMF-3, is scheduled for Tuesday evening. It will be an apogee burn to raise perigee to geosynchronous and our period to one day per orbit.
03.12.10 - The first Trim Motor Firing (TMF #1) was successfully completed Thursday evening. This apogee burn raised our perigee to 35,300 km, an orbital period of 23.6 hr. This means we are drifting 6 degrees to the east in every orbit. Two more thruster burns will be done, TMF #2 is a perigee burn to raise the apogee to its final value and TMF #3 is an apogee burn to raise the perigee to its final value.
03.10.10 - Tuesday night the main engine fuel and oxidizer lines were vented. SDO will now fly on thrusters for orbit station keeping and momentum control. Many thanks to the SDO propulsion team for building SDO's bi-prop system, the first to be designed and built at Goddard. Our next orbital maneuver (TMF #1) is scheduled for Thursday evening.
03.09.10 - Apogee Motor Firing #8, the last orbit raising maneuver, was successfully completed Monday night. This burn raised the SDO perigee altitude to about 34,600 km for a period of about 23 hr. With this orbit SDO will appear to drift eastward toward our final longitude.
03.06.10 - A successful Apogee Motor Firing #7 continued the string of smooth Main Engine burns since we removed the structural filter and lengthened the settling burn. AMF-7 raised our perigee altitude to approximately 25000 km, giving SDO an orbital period of about 19.2 hours. This sets SDO for one last trip "around the world" before Monday's AMF-8 actually moves SDO into a nearly geosynchronous orbit.
03.04.10 - Here is the SDO orbit so far. The initial GTO, two intermediate orbits, and the estimated final orbit are shown to scale. Apogee Motor Firings (AMFs) all take place at the apogee of the orbit (the left side of the diagram) and are designed to lift the perigee (where SDO is closest to the Earth) up to a geosynchronous altitude. A few trim maneuvers will then move SDO into its final orbit. Perigee values are altitudes (height above the Earth).
03.03.10 - Apogee Motor Firing #6 was successfully completed Tuesday evening. The burn used about 6 minutes of ACS thruster firing and 13 minutes of Main Engine firing. This maneuver raised the SDO perigee altitude to about 20,100 km, or a period of 17.4 hr. The GNC team reported that the Main Engine burn was extremely quiet and the momentum disturbance due to the fuel sloshing was minimal. Due to the equipment outage at the Santiago ground station, most of ranging this evening was performed by SDOGS.
03.01.10 - Apogee Motor Firing #5 used the ACS thrusters and main engine to raise the perigee altitude of SDO to about 15,000 km on the way to our target of 35,800 km. (Using Kepler's law, my estimate of the current orbital period is about 15.4 hr.) We had a very smooth burn so we will use the main engine for the next burn that is scheduled for Tuesday evening.
02.27.10 - Apogee Motor Firing #4, a 50-minute burn using the ACS thrusters, was performed successfully on Friday. Our perigee altitude is now greater than 10,000 km as it continues to move away from the Earth toward a circular GEO orbit. The Slosh Tiger Team is recommending some tweaking to the ACS controller to allow main engine burns to resume. We are meeting today to discuss a "hybrid" burn for Sunday, 40 minutes on the ACS thrusters, followed by a 10-minute main engine burn.
02.26.10 - Thursday on SDO: HMI & AIA completed their initial mechanism checkouts. Every instrument mechanism was moved in both directions. With the initial checkout complete HMI began their mechanism functional tests and completed testing the shutter mechanisms. The remainder of the HMI and AIA functional mechanism tests are scheduled for Saturday. EVE powered on their CCD survival patch heater.
02.25.10 - SDO operated its ACS Science Control Mode for the first time on Thursday. In "science mode" the spacecraft uses AIA Guide Telescope signals for fine sun-pointing control. SDO stayed in science mode for more than an hour after which it was commanded back to inertial mode. Science mode worked very well.
02.24.10 - While the EVE team continues to be busy with instrument commissioning, there is another task at hand that is critical to the success of the EVE instrument. This is preparing the first of five calibration sounding rockets that is set to launch May 5 from White Sands Missile range outside of Las Cruces, New Mexico. This sounding rocket carries an almost exact replica EVE instrument as the satellite version SDO EVE instrument.
02.24.10 - Apogee Motor Firing #3, a 50-minute burn using the ACS thrusters, completed this evening with no issues.
02.23.10 - The waves created by the SDO Launch are the Astronomy Picture of the Day for February 23, 2010. You can see the sundog on the right side of the picture and the rocket in the middle.
02.23.10 - HMI powered on the Image Stabilization System and both cameras. The operational heaters set points were increased from 10C to 15C and are controlling the instrument temperature nicely. The instrument is responding nominally.