Sunday, August 14, 2016

SpaceX Launches JCSAT-16, Lands Falcon 9 First Stage

Falcon 9 launches the JCSAT-16 satellite on Aug. 14. Credit: SpaceX

Night briefly turned into day as SpaceX’s Falcon 9, carrying the Japanese JCSAT-16 satellite, leapt of the pad for the black of space. The launch took place at 1:36 a.m. EDT (05:36 GMT) Aug. 14 from Cape Canaveral Air Force Station’s Space Launch Complex 40 (SLC-40) in Florida. About nine minutes later the first stage of the rocket, after doing its part in pushing the telecommunications satellite toward geostationary transfer orbit (GTO), landed on the Autonomous Spaceport Drone Ship “Of Course I Still Love You.” The platform was some 400 miles (640 kilometers) downrange in the Atlantic Ocean.

Supporting today’s launch was the U.S. Air Force’s 45th Space Wing. They provided weather forecasts and range operations as well as their network of radar, telemetry and communications instrumentation to facilitate a successful launch.

“I am very proud of the entire Space Coast team,” said Walk Jackim, 45th Space Wing vice commander and mission Launch Decision Authority. “Their flawless work made this mission a success. Assured access to space remains a difficult and challenging endeavor.”

Today’s flight launched at the beginning of a two hour launch window. The weather was predicted by the 45th Space Squadron as having only a 20 percent change of unfavorable weather. The primary concerns were cumulus and think clouds. However, weather remained remained green all throughout the countdown. The weather was humid with a slight ground haze at the ITL Causeway some three miles from the launch pad. The sky ended up being partly cloudy with stars easily visible.

This was the second time the Japanese JSAT Corporation tasked SpaceX with launching one of their satellites into orbit. The first was JCSAT-14, which launched about three months ago in early May.



The Falcon 9 with the JCSAT-16 payload on top was rolled atop the Transporter Erector out of the company’s Horizontal Integration Facility and rotated vertical at SLC-40. There it sat for the next couple of hours as engineers performed their final tasks ahead of the launch.

Not much happened visibly with the rocket until about 35 minutes before launch. This version of the Falcon 9, Full Thrust, utilizes super-chilled propellant. The liquid oxygen (LOX) and rocket grade kerosene (RP-1) was chilled to near their respective freezing points. This densifies the propellant and allows for more to fit in the same tank volume.

The Full Thrust Falcon 9 has an empty mass of about 1,194,000 pounds (541,300 kilograms) and is about 12 feet in diameters. According to SpaceX, the rocket is capable of sending approximately 28,991 pounds (13,150 kilograms) to LEO or 10,692 pounds (4,850 kilograms) to a GTO.

At about three seconds prior to lifting off the pad, the first stage’s nine Merlin 1D engines ignited and throttled to full power. After the computer verified all was well with the engines, the latches that held the 229.6-foot (70-meter) tall vehicle to Terra firma let go and the whole stack began to rise.

Within the first minute, the vehicle rose up, and turned toward the target orbit. At one minute and 18 seconds, the vehicle underwent its expected peak mechanical stress (Max Q) as the resistance of the thick atmosphere tried to crush the vehicle like a can. However, all went as planned, and the vehicle continued.

At two minutes and 33 seconds, the nine Merlin engines of the first stage cut out as planned. Three seconds later, coasting at some 5,000 mph (8,100 kph), the first and second stages separated. Eight seconds after that, the single Merlin Vacuum engine on the second stage ignited to continue pushing JCSAT-16 to GTO.

The launch fairing that encapsulated the satellite to protect it from the friction of the lower atmosphere separated at three minutes 32 seconds. As the vehicle was well above any atmosphere that could damage the valuable payload, it was no longer needed.

SpaceX hopes to eventually recover the payload fairings on its rockets on future flights, in addition to the first stage.

Eight minutes and 32 seconds into the flight, second stage engine cutoff occurred, placing the vehicle in a parking orbit. This began a coast phase that lasted about eighteen minutes.

All while the second stage was powering toward a parking orbit, the first stage began its return back to Earth.

As the Falcon 9 was pushing toward GTO, the first stage was in a high-energy sub-orbital trajectory. Because of this, the first stage did not have enough fuel to return to Cape Canaveral.

In a ground landing scenario, the booster would turn around and perform a boostback burn. However, in this case, it skipped that burn and continued on its trajectory before performing a reentry burn to cushion the vehicle as it entered the dense atmosphere.

Nearly hitting the center of the drone ship, SpaceX pulls off their fourth Falcon 9 first stage landing at sea. Credit: SpaceX
Nearly hitting the center of the drone ship, SpaceX pulls off their fourth Falcon 9 first stage landing at sea. Credit: SpaceX

It was at this time the grid fins began steering the rocket to preserve thruster fuel. After the reentry burn, the first stage was on a course for the drone ship. It would only light its engines at the last moments before landing – called a hoverslam. This is because the stage is so light that even a single engine at its lowest throttle setting (about 70 percent) cannot hover. Instead the booster must zero out its velocity around the same time its altitude equals zero before cutting the engines off. This last burn utilized the center Merlin engine.

When the stage got to just above the drone ship, the legs deployed and the rocket performed a successful landing – the fourth successful at sea and sixth overall.

In the coming days, the SpaceX engineers at sea will safe the rocket before towing the drone ship back to Port Canaveral for offloading. This process usually takes anywhere from four days to a week.

Meanwhile, back in orbit, at the predetermined moment, about 26 minutes and 30 seconds after launching, the second stage engine reignited to propel it and JCSAT-16 into GTO. That second burn lasted approximately one minute.

About four and a half minutes later, some 32 minutes after leaving Cape Canaveral, JCSAT-16 separated from the second stage completing SpaceX’s portion of the mission. Later, the satellite will have to deploy solar arrays and antennas. Additionally, the onboard thrusters will begin to circularize the orbit over the coming weeks and months.

Ultimately, JCSAT-16 will reside in a geostationary orbit at 162 degrees longitude. It will serve as an on-orbit spare for the JCSAT fleet. In particular, it will back up JSAT’s Superbird B2 satellite, which was launched in 2000 atop an Ariane 4 booster.

The Space Systems Loral-built satellite employs an array of Ku and Ka-band transponders and antennas in order to provide communications services across Asia. SKY Perfect JSAT offers a wide range of services, including video distribution as well as data transfer communications in Asia, Russia, Oceania, the Middle East and North America.

This launch of the Falcon 9 marked the eighth flight of the year for SpaceX – a calendar year record for the NewSpace company. There are still at least eight more missions planned before the end of the year, including another cargo run to the International Space Station by the company’s Dragon spacecraft.

The company’s next flight is expected to occur Sept. 2, also at SLC-40. That launch will send the AMOS-6 satellite to orbit to provide broadband coverage to Europe, the Middle East and Africa.

Written by: Derek Richardson
Original source: spaceflightinsider.com

No comments:

Post a Comment