Solar Orbiter (SolO) – Atlas V 411 – Canaveral SLC-41 – 10.02.2020 – 07:05 ДМВ

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Feb 10 06:26

The Automatic Determination and Dissemination of Just Updated Steering Terms, better known as the ADDJUST file, is being loaded into the Atlas V rocket's Inertial Navigation and Control Assembly (INCA) flight computer by the flight control operator here at the Launch Control Center. This is the planned steering parameters for the INCA to use based on today's upper level wind conditions.

A series of weather balloons has been launched throughout the countdown from the Range weather station at Cape Canaveral to collect measurements of wind speeds and directions to determine if conditions aloft violate the controllability or structural loads on the rocket during ascent. The balloon data was transmitted to ULA engineers in Denver to select a steering profile that minimizes launch vehicle responses.

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Feb 10 06:28

Initial telemetry coverage of this evening's flight of the Atlas V rocket will be relayed via the TEL-4 tracking station here at the Cape. The Jonathan Dickinson Missile Tracking Annex (JDMTA) in South Florida will acquire the vehicle shortly after liftoff. A handoff from the ground sites to NASA's orbiting Tracking and Data Relay Satellites in geosynchronous orbit occurs during the initial burn of the Centaur and TDRS satellites continue for the rest of the mission.

Solar Orbiter will communicate with Earth via ESA's deep space tracking network, ESTRACK. All operations are conducted by the European Space Operations Centre (ESOC) in Darmstadt, Germany. The Science Operations Centre located at ESA's European Space Astronomy Centre, ESAC, in Villanueva de la Cañada, Spain, will be responsible for science operations planning, and for archiving the mission's data for scientists to use.

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Feb 10 06:34

Weather is go!

Weather is observed and forecast GO for liftoff at 11:03 p.m. EST (0403 UTC) today, according to the countdown's final planned briefing by weather officer Jessica Williams.

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Feb 10 06:38

Three video cameras aboard the Atlas V rocket will be used to record key portions of today's mission. An aft-facing camera on the first stage will provide views of the vehicle climbing away from the Earth, solid rocket motor jettison and all the way nearly to staging. Just prior to booster engine cutoff, the view will switch to the aft-facing camera on the Centaur stage to show the first stage separating and ignition of the RL10A-4-2 engine. That same view will be available for the end of the first burn and then the ignition and shutdown of the engine on the second and third burns of the day. In addition, a forward-facing camera on Centaur will capture payload fairing jettison and Solar Orbiter spacecraft separation.

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02/10/2020 06:41 Stephen Clark

The ULA launch team is loading the trajectory profile for today's flight into the Atlas 5 rocket's guidance computer. The profile takes into account day-of-launch conditions, such as upper level winds.

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Feb 10 06:44

Countdown holding

T-minus 4 minutes and holding. The countdown has entered the planned 15-minute built-in hold designed to give a bit of margin to deal with any problems. Also during this time, the final readiness polls of the launch team and management members will be performed.

We remain on schedule for a liftoff at 11:03 p.m. EST (0403 UTC) from Space Launch Complex-41 at Cape Canaveral.

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Feb 10 06:45

Today's launch availability lasts from 11:03 p.m. EST (0403 UTC) to 1:03 a.m. EST (0603 UTC). Liftoff is possible every five minutes within that two-hour period, for a total of 25 opportunities at launch tonight.

The Atlas V rocket has the ability to launch Solar Orbiter during a three-week window that is dictated by the alignment of Earth and Venus, which will play key roles throughout Solar Orbiter's mission. Over the next 10 years, the spacecraft will periodically swing by Venus eight times and Earth once to receive gravity-assists in order to shape its orbit around the sun.

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Feb 10 06:47

This is Atlas Launch Control at T-minus 4 minutes and holding, with 12 minutes remaining in the built-in hold.

United Launch Alliance is using the Atlas V 411 rocket, with a four-meter-diameter payload fairing and one strap-on solid rocket booster, to launch Solar Orbiter for the European Space Agency and NASA.

Leaving the pad on 1.2 million pounds of thrust from the combined power of the kerosene-fueled first stage main engine and solid, the Atlas V will perform pitch, yaw and roll maneuvers to align with a due east heading along a flight azimuth of 104 degrees.

The vehicle will hit Mach 1, the speed of sound, in 58 seconds and pass through Max Q, the region of maximum dynamic pressure, at 69 seconds.

The solid booster will burn out and separate in less than two-and-a-half minutes. Cutoff of the main engine and staging occurs four minutes after launch, allowing the cryogenic Centaur upper stage to ignite for an 8-minute initial burn to reach a preliminary parking orbit. Just after ignition, the payload fairing that protected the satellite during atmospheric ascent will be jettisoned at the edge of space.

A half-hour coast through space between upper stage burns sets up the Centaur to perform another 7-minute burn that accelerates the payload into a highly elliptical, hyperbolic Earth departure orbit at escape velocity.

Spacecraft separation is expected at T+plus 52 minutes.

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Feb 10 06:51

Operating in extreme environments

Solar Orbiter must operate for years in one of the most hostile regions of the solar system. At closest approach, approximately 26 million miles (42 million kilometers) from the sun, it will be at just over a quarter of the distance between the star and our planet, well inside the orbit of inner planet Mercury. This close to the sun, the spacecraft will be exposed to sunlight 13 times more intense than what we feel on Earth.[


(From ESA press kit)⁠

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