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Archive for 2004

06-Jun-04 | Delays

Both June launches have been pushed back by about a week due to concerns with their launch vehicles. A first stage hydraulic pump aboard the Delta II at Vandenberg (preparing to launch NASA’s Aura spacecraft) failed a pre-flight test and had to be swapped out. The pump aboard the Delta II at Canaveral (for NAVSTAR IIR-12) was from a similar production lot and thus was replaced as well. {I am looking for confirmation that this pump is part of the main engine steering system. -ed.}

This has delayed the launch of the Air Force GPS replenishment satellite until the evening of Friday, 11 June. Aura has further problems with its launch vehicle, however, with an unspecified issue in the second stage helium pressurization system. It is now slated to fly in the morning of 26 June.

Meanwhile, NASA’s Mercury orbiter MESSENGER waits patiently (at the Astrotech Space Operations facilities near KSC) for the pad at SLC-17B to clear. It is hoped that NAVSTAR IIR-12 can launch in time for stacking operations for MESSENGER’s Delta II-Heavy to begin on 21 June.

23-Apr-04 | Delta flight 304 – Gravity Probe B

The second attempt at launching Gravity Probe B was a complete success, marking the 57th consecutive successful launch for Delta II.

A perfectly uneventful terminal countdown allowed the two-stage Delta 7920 to leave Pad 2W at Vandenberg at the exact time of its launch window, with an offical range liftoff time of 16:57:23.734 GMT.

All systems functioned nominally, the vehicle carrying its spent ground-lit solid motors for an extra twenty seconds or so in order to put them in the drop zone beyond the offshore oil platforms of central California. The 10-foot-diameter composite payload fairing was dropped soon after second stage ignition, and following a pair of second stage burns with a long intervening coast phase, the spacecraft was deployed into a nearly-circular polar orbit of about 356 nautical miles.

NASA Launch Manager Chuck Duvale said, “The initial predictions seem to be right on — the Delta II put us right where we needed to be.”

Gravity Probe B will spend two years making precise measurements of the effect Earth’s rotating mass has on the orbit of the spacecraft, an effect first predicted by Einstein’s general theory of relativity in 1920. The mathematical explanation of this theorized effect is esoteric and complicated (and this author cannot claim to suss it), but suffice to say that if you understand that mass distorts and warps the fabric of spacetime, you might grasp that a spinning mass can drag that same fabric, ever so slightly, around with it as it spins. Scientists have been waiting over forty years, since the earliest days of spaceflight and orbital science, to have a spacecraft sophisticated enough to measure this effect conclusively. In contrast, getting GP-B from proposal to orbit has taken a “mere” twelve years.

As an aside, the first experimental evidence of “frame dragging” was provided by the LAGEOS satellites and announced by NASA back in 1998. LAGEOS 1 was launched aboard Delta 123 on 4 May, 1976. (27-Mar-98 NASA Press Release)

19-Apr-04 | GP-B scrubbed

SCRUB! The first attempt at launching Gravity Probe B has been called off. Upper level winds had been a constraint for much of the morning, yet had come within acceptable parameters in time to come out of the scheduled T-minus 4 minute hold. But with about 3 minutes remaining in the countdown, Boeing engineers found they had insufficient time to confirm that the proper flight profile for the current upper level wind conditions had been uploaded to the Delta’s RIFCA.  Thus, Boeing manager Rich Murphy called a hold, resulting in a one-day turnaround. The next attempt will be Tuesday, 20 April.

15-Apr-04 | GPS launch moved up

To accomodate the postponement of MESSENGER, the Air Force has moved up the launch of NAVSTAR IIR-12 to early June. This was due to the fact that only SLC-17B has the engineering modifications necessary to allow the use of the larger GEM-46 booster motors of MESSENGER’s Delta II-Heavy.

15-Apr-04 | Aura arrives at VAFB

Also at Vandenberg Air Force Base, NASA’s Aura spacecraft has arrived to begin pre-launch preparations following an overland journey from Northrop Grumman’s Space Park manufacturing facility in Redondo Beach, California.  Aura, the latest addition to the Earth Observing System (EOS) that also includes Terra (launched on an Atlas) and Aqua (Delta 291, 04-May-02), is currently scheduled to launch in mid-June. (NASA Press Release, 06-Apr-04)

15-Apr-04 | Next launch

The next Delta launch will be Gravity Probe B, an intriguing Einsteinian relativity experiment. The spacecraft has been installed atop its two-stage Delta II at Vandenberg’s SLC-2W, and is ready to go on Monday, 19 April. (This is a two-day delay from its previous schedule.) Each launch opportunity is an instantaneous window, so any unexpected hold in the countdown will require a turnaround of at least 23 hours and 56 minutes. Upcoming windows are:

The two-day stand down in the middle of the week would be necessary to replenish the spacecraft’s Dewar tank with cryogenic helium, which is needed to keep GP-B’s highly sensitive gyroscopes cool.

25-Mar-04 | MESSENGER rescheduled

NASA has rescheduled the launch of MESSENGER from May to no earlier than 30 July.  Additional testing of the spacecraft’s fault-protection system software was cited as one of several factors.  “A more comfortable spacecraft processing schedule” was another, though this comes at the cost of cutting it close on the launch window, which only extends through 13 August. MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging; the coolest [if most contrived] acronym ever), if it launches in time, will be the first attempt to orbit the closest planet to the sun. (NASA ELV Status Report, 24-Mar-04)

21-Mar-04 | Delta flight 303 – NAVSTAR IIR-11

Flight number 303, the first Delta launch of 2004, took place yesterday at Cape Canaveral’s SLC-17B. The three-stage Delta II 7925 carried NAVSTAR IIR-11, a replenishment satellite for the USAF‘s Global Positioning System space segment.

A quiet countdown was interrupted with less than a minute remaining by a pressure alarm in the first stage nitrogen system. The launch team had a chance to show off their quick T-minus 4-minute turnaround skills and was able to launch at an official time of 12:53:00.409 EST, a minute ahead of the close of the 15-minute window.

Spacecraft separation came 68 minutes, 14 seconds later, into an 11,000-mile (apogee) transfer orbit. NAVSTAR IIR-11 will replace IIA-19, which has been on orbit for eleven years; a plaque mounted on IIR-11 celebrates the late Dr. Ivan A. Getting, a space pioneer who is “credited as the visionary behind GPS.”

Boeing announced this flight as “the 50th [GPS] satellite launched,” a number which includes the Block I experimental constellation as well as two launch failures (an Atlas E in 1981, and Delta 241 on 17 January 1997). Successful launches into the operational constellation now number 38. (Spaceflight Now, 20-Mar-04; Boeing Press Release, 20-Mar-04)

18-Mar-04 | Spitzer finds Oort cloud object

NASA has announced the discovery of the furthest object known in the solar system, now named Sedna after the Inuit goddess of the ocean. With the help of the Spitzer Space Telescope, scientists determined it must be no more than about 1,000 miles in diameter. Larger than an asteroid and smaller than Pluto, the “planetoid” defies easy classification and may be the first known member of the long-hypothesized Oort Cloud. (NASA Press Release, 15-Mar-04)

04-Mar-04 | Opportunity suggests water on Mars

If you were betting on Mars Exploration Rover Opportunity in the office pool, it’s time to collect. On Tuesday, 2 March, Opportunity‘s principal investigator announced that the rover has returned “strong evidence” that the Meridiani Planum region of Mars once held flowing, liquid water. Both Opportunity and its sister rover, Spirit, are in good shape, have spent a combined total of 99 Martian days on the surface, and are likely to continue to collect important data for some time to come. (NASA Press Release, 02-Mar-04)

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