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Archive for October, 2001


31-Oct-01 | IMP-8, venerable solar wind Explorer, shut down

One of NASA’s oldest continuing missions has come to an end.

On Sunday, 28 October, the last commands were sent to the Interplanetary Monitoring Platform IMP-8, retiring the spacecraft from service. Launched in the evening of 25 October 1973 aboard a three-stage Delta rocket, IMP-8 spent the last 28 years measuring the magnetic fields, plasmas, and energetic charged particles of the solar wind as it interacts with Earth’s magnetotail and magnetosheath. It was the fiftieth mission in the long-running Explorer series.

Like EUVE earlier this year, NASA claims that IMP-8 has fallen behind the curve of diminishing science returns versus continuing funding. Its magnetometer failed in 2000, depriving scientists of its primary instrument, yet six of IMP-8’s original twelve instruments continue to function.

In its 28 years of service, IMP-8 has provided data for over 1,000 published scientific papers, several hundred in the last 5 years alone. It also was the impetus for a low-cost, ad hoc data collection system utilizing new technologies after the Spaceflight Tracking and Data Network, capable of receiving IMP-8’s now-obsolete VHF transmissions, was “largely disestablished.” (30-Oct-01 NASA Press Release)


26-Oct-01 | Mars Odyssey reaches orbit

On Tuesday, 23 October 2001, 2001 Mars Odyssey successfully entered orbit around the Red Planet.

At about 02:26 (UTC, 24 October; all times are Earth-received, not Mars local), MO lit up its main engine for a duration of about 19 minutes. Just over 10 minutes later the spacecraft passed behind Mars from Earth’s perspective, and all contact was lost as expected. The engine shut down on time, but it wasn’t until 02:56 that MO passed out of occultation and the Deep Space Network reacquired its signal. Controllers were relieved to discover that all events in the complicated manoeuvre occurred on time, and Mars Odyssey was found to be in a highly elliptic, 160 by 15,000 nautical mile orbit with a duration of 18 hours, 36 minutes.

Aerobraking will begin on Friday, 26 October, and is expected to take about 3 months to put MO in a circular, approximately 220 nautical mile orbit. Mapping operations will then commence and continue for an estimated 917 Earth days, around 1-1/3 Martian years.

With the announcement last week of NASA Administrator Daniel Goldin’s pending retirement, all eyes are on Mars Odyssey as it strives to vindicate the “Faster, Better, Cheaper” policy that Goldin championed during his tenure. NASA’s two previous Mars missions, Mars Climate Orbiter and Mars Polar Lander/Deep Space 2, were both lost on arrival at the Red Planet. “Danny G.” was on hand Tuesday at JPL to lead the post-arrival news conference regardless of outcome, and was obviously pleased to have good news to report. Tuesday’s encounter was the riskiest phase of its mission, but MO still has to survive its tricky aerobraking phase before it will return any substantial science. In addition, the flight team has yet to resolve issues with the navigational star tracker and one of the primary instruments, the Martian radiation environment experiment (MARIE).


20-Oct-01 | Delta flight 288 – QuickBird 2

On Thursday, 18 October, the 288th Delta launched QuickBird 2, an Earth imaging satellite owned by DigitalGlobe. The satellite, when it becomes operational in February, is expected to provide the highest-resolution images available on the commercial market.

The two-stage Delta 7320, sporting three booster motors and a 10-foot diameter composite fairing, left Vandenberg’s SLC-2W at 11:51:26.242 PDT after a problem-free terminal count. The Ball Aerospace-built spacecraft was deployed into a nominal 243 nautical mile circular orbit just over an hour later. Like most Delta launches from the west coast, QuickBird’s orbit is polar and sun-synchronous, which will allow maximum coverage of the Earth’s surface.

According to Spaceflight Now, the usual controller “ground loop” audio was unavailable for this flight, hindering that site’s ability to provide what is usually quite detailed play-by-play coverage. Whether this was merely a technical glitch or an intentional security measure by the Air Force has not been determined.

This was the third attempt for DigitalGlobe (formerly known as EarthWatch), which is based in Longmont, Colo. Their first satellite, EarlyBird — not to be confused with Intelsat 1 — suffered a power system malfunction four days after its launch in 1997. QuickBird 1 was lost in November 2000 when the second stage of its Russian-built Kosmos-3M launch vehicle failed to restart at apogee, possibly due to oxidizer contamination. Despite the substantially increased cost versus Russian rockets with similar capacity, DigitalGlobe chose Delta II for this flight thanks to the vehicle’s exceptional reliability. “We looked at it and said ‘here is the most reliable rocket in the U.S. inventory, in the kind of class we can fly in and it is just an outstanding rocket,'” said Herb Satterlee, DigitalGlobe president and CEO.


     

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