After back-to-back delays earlier this week, a workhorse Delta 2 rocket finally streaked away from the California coast early Saturday carrying a state-of-the-art $1.6 billion weather satellite into an orbit around Earth's poles, the first of four intended to ensure reliable forecasting over the next two decades.
The Delta 2, making the venerable rocket's 154th flight since its debut in 1989, thundered to life with a crackling roar at 1:47:36 a.m. PST (GMT-8), quickly shooting away from launch complex 2-West at Vandenberg Air Force Base, California, and arcing away to the south over the Pacific Ocean.
A launch try Tuesday was scrubbed at the last minute by a technical issue and by boats that strayed into the offshore launch danger zone. A second try 24 hours later was called off because of higher-than-allowable winds aloft.
But it was clear sailing the third time around and the 128-foot-tall half-million-pound Delta 2 put on a spectacular show as it shot into the deep overnight sky trailing a long jet of brilliant flame and churning exhaust.
Six solid-fuel strap-on boosters burned out and fell away as expected about a minute and a half after launch, followed a few moments later by three that were ignited in flight. The Delta 2's first stage RS-27A engine shut down and fell away a little more than two minutes later and the flight continued on the power of the rocket's AJ10 second stage engine.
The second stage reached the intended preliminary orbit about 10 minutes and 38 seconds after launch. A second engine firing 40 minutes later completed the trip to a 512-mile-high 101-minute orbit around Earth's poles that will allow the Joint Polar Satellite System 1 weather station to monitor the entire planet as it rotates below.
Along with delivering JPSS 1 to the required orbit, the Delta 2 second stage also carried five small "cubesat" science and technology demonstration satellites into space that were released about 85 minutes after launch. But the new weather satellite was the clear star of the show.
Built by Ball Aerospace, the JPSS 1 satellite is the first of four in an $11.3 billion National Oceanic and Atmospheric Administration (NOAA) program to provide continuous low-Earth orbit weather monitoring through 2038.
The polar orbiters will work with the more familiar Geostationary Operational Environmental Satellites -- GOES -- weather stations that provide hemispheric views from their lofty perches 22,300 miles above the equator.
But it is the polar orbiters that provide the lion's share -- 85 percent -- of the data needed by the computer models to generate the forecasts familiar from nightly television newscasts.
JPSS 1 will share its orbit with Suomi NPP, a satellite launched in 2011 to serve as a test bed for the sophisticated instruments featured in the Joint Polar Satellite System spacecraft. While it was launched as a research satellite, Suomi NPP is now considered operational.
But the spacecraft is aging and JPSS 1 will ensure uninterrupted, more accurate forecasting in the event of problems with the older satellite.
"NOAA's mission as an operational agency is to be the trusted deliverer of Earth observations without interruption," said Steve Volz, director of Satellite and Information Services for NOAA.
"Many of the national infrastructure elements ... rely on knowing the weather forecasts will be there every day, every six hours, without interruption. So The main contribution this satellite provides ... is we will have a primary and a spare satellite. We won't be at the risk of a single failure taking out a major contribution of our weather forecasting."
The once experimental instruments aboard Suomi NPP proved their worth during this year's hurricane season when Harvey, Irma and Maria wreaked havoc in the United States and devastated Puerto Rico. In all three cases, NOAA satellites provided the data needed to generate accurate forecasts, giving residents time to make preparations.
"The forecasting that you've seen are impossible without robust, high-quality global measurements of the atmosphere required to initialize our numerical weather prediction systems," said said Louis W. Uccellini, director of the National Weather Service.
"Polar satellites are the only way to obtain global temperature and moisture measurements, and they are the backbone of the global observing system that we use to make these predictions of extreme events."
JPSS 1 is equipped with five sophisticated instruments to measure sea and land surface temperatures and atmospheric moisture, to monitor vegetation, rainfall, snow and ice around the world, to pinpoint wildfires, volcanic eruptions and to measure ozone concentrations.
"JPSS delivers key observations for ... forecasting severe weather like hurricanes, tornadoes and blizzards days in advance, and assessing environmental hazards such as droughts, forest fires, poor air quality and harmful coastal waters," according to the JPSS web site.
The new satellite "will provide continuity of critical, global Earth observations, including our atmosphere, oceans and land through 2038."
JPSS 1 is expected to begin routine observations after about three months of tests and checkout.