Author: Anna Heiney

NASA Launch Manager Tim Dunn just conducted a poll to verify his team is “go” for launch at 1:42:18 p.m. EST.

The countdown continues to progress smoothly toward liftoff of the SpaceX Falcon 9 rocket carrying the Jason-3 satellite. Launch remains scheduled for 10:42 a.m. PST / 1:42 p.m. EST at the start of a 30-second window of opportunity. The spacecraft is reported “green” and the Western Range is conducting a final check of its tracking systems.

Since the Jason-3 satellite needs to carry on the work of Jason-2 and Jason-1, it will fly at an altitude of about 1300 km on the same orbital track as its predecessors, making observations over the same location every 9.9 days.

Launch Weather Officer Lt. Joseph Round just briefed the launch team on weather conditions now and at launch time, and the forecast is unchanged. There is no chance of violating any  weather-related launch constraints; weather is “green,” or “go,” on all criteria. Although the launch pad remains socked in with coastal fog, this is not a concern for launch. Upper-level winds are “green” as well.

“Flying 1300 km high, at 6 km per second, while measuring sea surface heights to about 4 cm,
requires a pretty sophisticated set of instruments,” Spacecraft Mission Director Parag Vaze, Jason-3 project manager at the Jet Propulsion Laboratory, said Friday.

Jason-3’s primary instrument is the Poseidon-3B Altimeter, a radar altimeter that measures variations in the sea level across the world’s oceans with an accuracy as high as 1.3 inches (or 3.3 centimeters). Its goal: an accuracy as high as 1 inch (or 2.5 centimeters). For a full rundown on all the instrumentation on board, visit http://www.nesdis.noaa.gov/jason-3/press.html.

The Jason-3 satellite weighs about 1,100 pounds and is about the size of a minivan — 3.3 feet by 3.3 feet by 12.1 feet — once its solar panels are deployed.

About 154 seconds after launch, the main engine will cut off, followed by separation of the first stage about three seconds later.

The second-stage engine will  ignite after another eight seconds. Half a minute into the second-stage burn, the payload fairing will be jettisoned, having done its job of protecting the Jason-3 satellite during the first three minutes of flight. The first cutoff of the second-stage engine will take place nine minutes after liftoff. At this point the Jason-3 spacecraft and Falcon 9 second stage will have entered a 46-minute coast phase.

The second-stage engine will ignite for its second burn about 55 minutes after launch. Once Jason-3 has reached the desired orbit, the rocket will separate from the spacecraft about half a minute later, nearly 56 minutes after liftoff.

PST/EST
8:42 a.m./11:42 a.m.        Flight termination system checks and collision avoidance coordination
9:42 a.m./12:42 p.m.        T-1 hour weather and launch status update
10:12 a.m./1:12 p.m.        Range tracking system check
10:22 a.m./1:22 p.m.        Jason-3 launch readiness poll
10:25 a.m./1:25 p.m.        NASA Launch Manager poll
10:29 a.m./1:29 p.m.        Terminal Countdown poll
10:32 a.m./1:32 p.m.        Terminal Countdown begins
10:38 a.m./1:38 p.m.        NASA go for launch
10:40 a.m./1:40 p.m.        Range Green
10:42:18 a.m./1:42:18 p.m.    Launch
10:44:48 a.m./1:44:48 p.m.    Falcon 9 Main Engine Cutoff (MECO)
10:44:54 a.m./1:44:54 p.m.    Falcon 9 Stage 1/2 Separate
10:45:03 a.m./1:45:03 p.m.     Falcon 9 second stage ignition
10:45:33 a.m./1:45:33 p.m.     Fairing jettisoned
10:51:18 a.m./1:51:18 p.m.     Falcon 9 second stage engine cutoff 1 (SECO 1)
11:37:24 a.m./2:37:24 p.m.     Falcon 9 second stage restart
11:37:36 a.m./2:37:36 p.m.     Falcon 9 second stage engine cutoff 2 (SECO 2)
11:38:06 a.m./2:38:06 p.m.     Jason-3 spacecraft separation
11:40:24 a.m./2:40:24 p.m.     Jason-3 solar array 1 deploy start
11:40:39 a.m./2:40:39 p.m.     Jason-3 solar array 1 deploy end
11:44:04 a.m./2:44:04 p.m.     Jason-3 solar array 2 deploy start
11:44:18 a.m./2:44:18 p.m.     Jason-3 solar array 2 deploy end

Image above: A coastal fog envelops the SpaceX Falcon 9 rocket waiting to launch the Jason-3 satellite from Vandenberg Air Force Base in California. The fog is not a concern for launch. Photo credit: NASA Television

Jason-3 is a four-agency international partnership consisting of NOAA, NASA, Centre National d’Etudes Spatiales, or CNES — France’s space agency — and the European Organization for the Exploitation of Meteorological Satellites, or EUMETSAT. Thales Alenia of France built the spacecraft.

According to Jim Silva, NOAA’s Jason-3 program manager, this international partnership is the secret to the mission’s success.

“This mission could not be possible without the productive collaboration between NOAA and its partners: EUMETSAT, the French space agency CNES, and NASA,” Silva said Friday.

The Jason-3 satellite is getting its boost into orbit aboard a SpaceX Falcon-9 rocket, a two-stage vehicle powered by nine Merlin engines on its first stage and a single Merlin engine on its second. The rocket has a 12-foot diameter and with the payload fairing installed stands 226 feet tall. This mission marks the first time SpaceX is launching a payload for NASA’s Launch Services Program.

The rocket moved to the launch pad Friday and was raised into launch position yesterday, and now it stands poised for liftoff.

“Everything is in great shape and the vehicle is really ready to go,” SpaceX Chief Engineer Hans Koenigsmann said Friday.

Image above: The SpaceX Falcon 9 rocket is rolled from a hangar at Vandenberg Air Force Base in California to Space Launch Complex 4 on Jan. 15. Photo credit: SpaceX

Jason-3 is the fourth in a U.S.-European series of satellite missions that measure the height of the ocean surface, extending the time series of ocean surface topography measurements that began with the TOPEX/Poseidon satellite mission in 1992 and has continued through the currently operating missions: Jason-1, launched in 2001, and OSTM/Jason-2, launched in 2008. The Jason-3 mission is planned to last at least three years, with a goal of five years.

“In my opinion, Jason-3 and its three predecessors — Topex-Poseidon, Jason-1 and Jason-2 — provide the most accurate measurements of global sea surface heights. Think of it: a satellite orbiting that is orbiting Earth more than 1300 kilometers away is able to tell us height of the sea surface with an accuracy of less than two inches,” Jim Silva, NOAA’s Jason-3 program manager, said Friday.

“To paraphrase from Charlotte’s Web, that is some satellite.”

One major advantage of Jason-3 over earlier satellites, Silva explained, is its improved algorithms. With Jason-3, forecasters and researchers will be able to determine wind speeds and ocean currents within about a kilometer from U.S. shorelines — a significant advantage over the spacecraft’s predecessors, which could detect these features about 10 kilometers from shore. That’s especially useful for search and rescue operations in the case of downed ships close to shore.