A French-built satellite tv for pc geared up with an revolutionary U.S.-made radar instrument is buttoned up for blastoff aboard a SpaceX Falcon 9 rocket Friday from California, kicking off a mission to analyze the hyperlink between Earth’s water cycle and our planet’s altering local weather.
The Floor Water and Ocean Topography, or SWOT, satellite tv for pc is ready for liftoff from Vandenberg Area Pressure Base, California, at 3:46:47 a.m. PST (6:46:47 a.m. EST; 1146:47 GMT) on the high of a Falcon 9 launcher. The Falcon 9, powered by 9 kerosene-fueled Merlin 1D predominant engines, will hearth off Area Launch Advanced 4-East at Vandenberg, a navy spaceport positioned roughly 140 miles (225 kilometers) northwest of Los Angeles.
The SWOT mission is a joint undertaking developed by NASA and CNES, the French house company, to make the primary international survey of Earth’s floor water. The SWOT mission builds upon earlier satellites which have measured rising sea ranges and the peak of ocean waves. However SWOT introduces a brand new instrument that may see finer particulars within the ocean’s floor roughness, and prolong the water measurements to freshwater our bodies like lakes and rivers.
“SWOT will present almost a whole view of the floor water on Earth,” mentioned Ben Hamlington, a sea stage researcher at NASA’s Jet Propulsion Laboratory. “Knowledge collected by SWOT over the land, over the ocean, and the place the land and ocean meet alongside our coastlines, goes to play a very vital function in informing us about our day by day lives and livelihoods.”
The Falcon 9 rocket will place the 4,850-pound (2,200-kilogram) SWOT satellite tv for pc into an orbit about 532 miles (857 kilometers) above Earth at an inclination of of 77.6 levels to the equator. SWOT will unfold its predominant science instrument, a two-wing radar interferometer, inside the first week of its mission, then start a six-month check marketing campaign earlier than starting science operations in mid-2023.
“SWOT is a sport changer,” mentioned Tahani Amer, NASA’s program govt for the mission. “Water connects all of us and we’re very excited to share the info from SWOT.”
Forecasters at Vandenberg predict a 100% chance of excellent climate for liftoff Friday, when SpaceX has a 10-minute launch window obtainable. The launch was delayed from Thursday to offer engineers time to guage outcomes of inspections on two of the Falcon 9’s predominant engines.
Julianna Scheiman, SpaceX’s director of civil satellite tv for pc missions, mentioned in a press convention Wednesday that technicians found the signature of moisture in two of the engines throughout launch preparations. Officers believed the moisture is probably going from heavy rain that fell on the Falcon 9 when it was on the launch pad final week for an engine test-firing.
However SpaceX carried out further inspections on the 2 engines on the launch pad at Vandenberg to find out whether or not the moisture is from water intrusion or one thing else. Mission managers cleared the Falcon 9 for flight in a gathering Thursday.
“Technicians accomplished information evaluations and the evaluation of the presence of moisture within the engines, which was found throughout routine inspections on Dec. 14,” NASA mentioned in a mission replace on its web site.
The primary stage booster flying on the SWOT mission is designated B1071, and is ready to make its sixth flight to house. The booster will hearth its 9 engines for greater than two minutes, accelerating the Falcon 9 previous the velocity of sound with 1.7 million kilos of thrust. The preliminary trajectory from Vandenberg will take the rocket southwest from California’s Central Coast, then veer south with a left-hand flip, or “dogleg” maneuver, to line up with the SWOT satellite tv for pc’s goal orbital aircraft.
The Falcon 9’s first stage will shut off its 9 engines, detach from the higher stage, after which reignite three of its engines for a “enhance again” burn to reverse course and return to Touchdown Zone 4 at Vandenberg, only a quarter-mile from the rocket’s launch pad. After extending 4 aerodynamic grid fins, the booster will return to a propulsive touchdown on 4 deployable legs about seven-and-a-half minutes after liftoff.
The higher stage, in the meantime, will proceed downrange to put the SWOT satellite tv for pc right into a preliminary parking orbit with a six-minute firing of its single Merlin engine. The rocket will coast over Antarctica and head northbound over the Indian Ocean earlier than lighting its engine once more 43 minutes into the mission for a short burn to circularize its orbit at about 532 miles altitude, with an inclination of 77.6 levels to the equator.
The SWOT spacecraft will separate from the Falcon 9’s higher stage about 52 minutes after liftoff. Floor groups in France will likely be on standby to obtain the primary radio indicators from the satellite tv for pc, and hope to substantiate the extension of power-generating photo voltaic panels on the SWOT spacecraft quickly after it arrives in orbit.
The SWOT mission builds on a sequence of U.S.-French satellites which have tracked rising sea ranges and measured ocean wave heights since 1992. However SWOT introduces a brand new kind of instrument, a Ka-band radar interferometer, with improved precision and a broader area of view than altimeters on older oceanography satellites.
The Ka-band radar interferometer, referred to as KaRIn, consists of two antennas mounted on booms 33 toes (10 meters) aside, about half the size of a tennis courtroom. One of many downward-facing antennas will transmit radar pulses, and each antennas on the instrument will measure the mirrored radar indicators that bounce off Earth’s floor. Scientists can derive the peak of water ranges in oceans, lakes, and rivers from the tiny distinction within the time the mirrored indicators arrive at every antenna.
“These antennas need to be stored extraordinarily secure and pointed on the similar place on the Earth inside just a few microns, which is smaller than a human hair,” mentioned Parag Vaze, SWOT undertaking supervisor at NASA’s Jet Propulsion Laboratory. “The radar sends electromagnetic pulses from one antenna that mirror off the floor of the Earth and are acquired by each antennas as the identical time. This supplies a really exact measurement of the peak utilizing a triangulation method referred to as interferometry. That lets us create a 2D map of the floor water.”
4 cameras on the SWOT satellite tv for pc will take photos of the spacecraft’s photo voltaic arrays and radar antenna deployment sequence, which is anticipated to take about 4 days and ought to be full round eight to 9 days after launch, Vaze mentioned.
“We’re anticipating to have some lovely imagery, and in addition a film of the antenna deployment particularly,” Vaze mentioned. “We predict it to be a pleasant finish of 12 months current.”
SWOT will hearth its small maneuvering thrusters to lift its orbit to an altitude of 553 miles (891 kilometers) earlier than commencing science observations subsequent 12 months. Scientists will calibrate the radar interferometer by evaluating its outcomes to reference measurements from earlier oceanography satellites.
“The measurement system is complicated, demanding extraordinary stability of the instrument and precision management of the massive spacecraft, making SWOT a really difficult mission,” mentioned Lee-Lueng Fu, SWOT’s undertaking scientist at JPL. “SWOT will cowl the world between 78 levels north and 78 levels south each 21 days, offering a excessive definition view of the floor water and ocean topography.”
As an alternative of accumulating information factors on sea stage and wave top in step with the satellite tv for pc’s floor observe, as earlier oceanography satellites did, SWOT’s instrument will make measurements in a swatch 75 miles (120 kilometers) large because it circles Earth each hour-and-a-half. SWOT’s measurements will likely be sharper than these from older oceanography satellites, which have been restricted to gathering information on sea stage and waves within the open ocean.
SWOT may have the decision to measure the water ranges in lakes and reservoirs, rivers, and in ocean waters nearer to coastlines. The finer element in information from SWOT will allow scientists to look at small-scale eddys the place the ocean absorbs warmth from the ambiance.
“Solely SWOT will have the ability to see the small eddys and fronts which are accountable or taking warmth from the ambiance,” Fu mentioned. “These are the oceanic analogs of thunderstorms, creating intense vertical motions, drawing down the warmth from the ambiance and storing it within the deep ocean. This new data will assist enhance ocean fashions for predicting the ocean’s capability sooner or later to proceed absorbing warmth to manage local weather change.”
The information from SWOT will likely be distributed worldwide free of charge, serving to local weather researchers, water administration companies, and catastrophe preparedness organizations observe the consequences of local weather change, monitor scarce water sources, and reply to floods and droughts.
“The commentary of floor water on land is what we have to assess the funds of freshwater,” Fu mentioned. “In a warming local weather, the Earth’s water cycle is accelerating, making water sources tough to trace and handle. The place is the water? The place does it come from? After which the place does it go? These are questions we’re not geared up to reply as a result of the world’s rivers and lakes are poorly sampled in lots of locations.
“SWOT will make a quantum bounce by making observations from house to create a world stock of water sources,” Fu mentioned. “Water can be a supply of hazards. If the water funds is out of steadiness, we’ll have both floods or drought. SWOT information will assist us enhance monitoring and forecasts of such perils.”
“SWOT information are going be used to observe drought circumstances, enhance flood forecasts, monitor reservoir quantity, and assess river stream,” Hamlington mentioned.
Other than the radar interferometer payload, SWOT carries a European-made radar altimeter just like devices flown on the Jason household of ocean monitoring satellites. Most lately, European and U.S. scientists teamed as much as develop and launch the Sentinel-6 Michael Freilich satellite tv for pc in 2020 to proceed the continual sea stage and wave top information report from the Jason sequence of ocean altimetry satellites.
SWOT has a NASA-provided microwave radiometer instrument to appropriate for errors within the radar interferometer indicators attributable to water vapor in Earth’s ambiance. And crucially, the satellite tv for pc carries tools to permit floor groups to find out its actual place in house with a precision of simply 1 centimeter, in response to Thierry Lafon, SWOT’s undertaking supervisor at CNES.
The satellites’s science payload will generate a terabyte of knowledge per day, Vaze mentioned. SWOT will transmit the info to the bottom with an X-band communications system.
Thales Alenia Area constructed the SWOT satellite tv for pc its it manufacturing unit in Cannes, France. NASA shipped the U.S.-made radar interferometer payload from JPL in California to the Thales satellite tv for pc meeting plant in France, then all the spacecraft was transported again to California in October on a U.S. navy C-5 cargo aircraft to start ultimate launch preparations.
An impartial panel of scientists recognized the SWOT mission as a excessive precedence in a 2007 decadal survey report, prompting NASA and CNES to decide to funding the undertaking.
The SWOT mission has value almost $1.2 billion to develop, construct, and launch. About two-thirds of the funding has come from NASA, and a lot of the the rest of the funds was offered by the French authorities. The UK Area Company and Canadian Area Company additionally provided smaller contributions to the mission.
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Observe Stephen Clark on Twitter: @StephenClark1.
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