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Archive for April, 2003

25-Apr-03 | Update

At SLC-17B, destacking operations for SIRTF are set to begin on Monday, 28 April. Contrary to an earlier report on this site, the launch vehicle’s first stage and seven of its nine booster motors will remain in place for use by MER-B. This seems to imply that two of the GEM-46 motors are suffering from delaminated nozzles, though official reports have stated only one motor was suspect. The Delta second stage must be removed in order to replace it with one with the proper attach fitting for a three-stage flight (and possibly also with a different pressure bottle configuration). MER-B is now set to launch on 25 June, no sooner than 10 days after the launch of MER-A. (NASA ELV Status Report, 25-Apr-03)

25-Apr-03 | Rover update

Good news for the Mars Exploration Rovers, as the circuit board rework and reinstallation is moving swiftly enough for the target launch date to move up by a day. MER-A is now set to launch on 5 June. Two instantaneous launch opporunities exist on each day through 19 June. At SLC-17A, first and second stage erection is in work this week. (NASA ELV Status Report, 25-Apr-03)

19-Apr-03 | Delays, delays

The Space Infrared Telescope Facility (SIRTF) has been delayed until no earlier than mid-August, NASA officials announced on Friday. (NASA Press Release, 18-Feb-03) The “unspecified concerns” of a week ago were revealed to be “multiple delaminations within the layers of material that comprise the engine-nozzle exit-cone liner” of one of the nine GEM-46 solid booster motors. As there is insufficient time to change out the questionable motor before 7 May, the payload and the entire vehicle will be destacked to clear Pad B for Mars Exploration Rover-B.

Meanwhile, the Mars Exploration Rovers have hit a snag as well. Pre-launch testing revealed the spacecraft’s main computer could misinterpret signals sent during data cable severing events. Two sets of cables connect the lander to the cruise stage (severed during approach) and the rover to the lander (severed before the rover drives off). The fix will require partial disassembly of the spacecraft, which pushed the first launch back from 30 May to 6 June. (Spaceflight Now, 14-Feb-03)

15-Apr-03 | Mars rovers at Kennedy

The Mars Exploration Rovers are at the Kennedy Space Center and are being processed. On Friday, NASA announced their destinations. MER-A, set to launch on 6 June, will land in Gusev Crater, 15 degrees south of Mars’ equator, on 4 January 2004. MER-B, scheduled for 25 June, will take a shorter, faster path to Meridiani Planum, about two degrees south of the equator and halfway around the planet from Gusev, landing on 25 January 2004. Each site reached the top of a highly selective list for reasons both engineering — a drivable terrain, for example — and scientific. Both sites have been extensively studied, and their rovers are instrumented to provide definitive evidence for or against specific hypotheses. (NASA Press Release, 11-Feb-03)

15-Apr-03 | SIRTF delay

The Space Infrared Telescope Facility (SIRTF) has been delayed. Boeing and NASA have raised unspecified concerns over the Delta II-Heavy’s GEM-46 booster motors, which have flown on three Delta III flights but are untested on Delta II. (Spaceflight Now, 10-Apr-03)

According to Boeing, the larger and longer boosters increase the Delta II’s capacity by approximately 19 percent, the largest performance upgrade for Delta II since 1990 (when the GEM-40 motors were introduced). The Delta first stage required beefed-up structure and acoustic blanket modifications to accomodate the motors as well.

At the pad, the standard skin-and-stringer 9.5-foot-diameter fairing is in place, and the program team members in the TCC are monitoring the payload closely. SIRTF has until 7 May to get off the pad, or the vehicle will be destacked and replaced with the Delta II-Heavy for the second Mars Rover, which has a very tight launch window that only comes around every 26 months. (SLC-17B is the only east coast pad that can launch Delta rockets equipped with GEM-46 motors, as its flame trench and other support systems were updated specifically for the heavier motors and their different acoustic signature. SLC-17A, which is scheduled to launch the first Rover on 6 June, is also precluded for the second Rover because the 19-day gap between the two Rover flights is insufficient to stack the Delta and properly prepare a payload with such potential public-interest value.)

15-Apr-03 | SIRTF update

NASA’s Space Infrared Telescope Facility (SIRTF) was bundled into its cylindrical transport container on Thursday, 3 April, and was hauled to SLC-17B in the early morning of 5 April. As of Saturday afternoon it had been hoisted into Level 9 of the Mobile Service Tower and attachment to the Delta second stage was in work. Barring any difficulties, expect fairing installation to take place early in the next week. Meanwhile, NASA has chosen to postpone announcement of the SIRTF Naming Contest winner until about four months after launch, to coincide with the release of the first images from the Great Observatory.

01-Apr-03 | Delta flight 297 – NAVSTAR IIR-9

Monday, 31 March, saw the launch of NAVSTAR IIR-9, a replenishment satellite for the U.S. Air Force’s Global Positioning System. Winds were gusty at the time of service tower rollback, causing the rocket to occasionally sway back and forth until it was weighted down with fuel and oxidizer, but subsided early enough that the countdown was essentially as clear as the blue skies at the Cape. A glitch with some Eastern Range hardware, coupled with a wayward aircraft that wandered momentarily into the exclusion zone, pushed the liftoff to the very end of the day’s window, which occurred at 17:09:00.850 EST.

The 297th Delta flight (the 106th for Delta II) went off flawlessly, placing Space Vehicle Number 45 into its proper transfer orbit just over 68 minutes after liftoff. In the next few days the satellite will boost itself into its operational orbit to replace NAVSTAR II-5, which launched aboard Delta 190 more than 13 years ago. (II-5 has some life left in it and will be moved into a “close pair” co-orbit with IIA-11 to serve as a backup.) The Global Positioning System, which consists of ground control and user segments in addition to the space segment, is an important part of the “smart munitions” being employed in America’s present conflict, and as such has been mentioned a lot lately in the media (which often mistakenly refer to it as “Global Positioning Satellite“). GPS is also widely used in civilian applications on land, sea, and in the air.

     

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