ULA's second launch of the month is scheduled for Thursday – Spaceflight Now



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"Sufficient moisture and a slight flow of direction should trigger isolated downpours and storms on Atlantic waters early Thursday morning," forecasters wrote. "Light winds will maintain the bulk of this offshore activity, but a downpour approaching the coast and / or flight path can not be ruled out."

The main weather concerns during Thursday's launch window concern the possibility of violating the cumulus rules and overflowing precipitation, according to forecasts released Monday.

At the launch window on Thursday, forecasters forecast isolated rain showers offshore, partly cloudy clouds, south-southeast winds of 8 knots and a temperature of 83 to 85 degrees Fahrenheit.

The latest pre-launch milestones this week include a readiness review at the launch scheduled for Tuesday. Platform 37 workers will complete the final rocket shutdown on Wednesday before moving the gantry crane to reveal the Delta 4 before refueling.

The Delta 4 rocket (207 meters) in height (63 meters) will distance itself from the 37 platform with 1.1 million pounds of thrust coming from a main Aerojet Rocketdyne RS-68 engine operating at the same time. Hydrogen and two powerful lane thrusters built by Northrop Grumman. Innovation systems.

Heading north-east, the Delta 4 will exceed the speed of sound in less than a minute and drop its solid propellant propellant to T + plus 1 minute 40 seconds.

The main floor motor RS-68 will stop at T + plus 3 minutes and 55 seconds, followed by a separation of steps approximately seven seconds later. An RL10 engine installed on the upper deck of the Delta, also built by Aerojet Rocketdyne, ignites on the first of two shots needed to place the GPS satellite into an elliptical transfer orbit.

The payload fairing of the Delta 4 will be dropped as a shell at T + plus 4 minutes 26 seconds, once the rocket has flown into the rarified upper atmosphere. The stay protects the payload of the GPS during launch preparations and ascent in the lower layers of the atmosphere.

The upper stage engine of the RL10 will turn off at T + plus 13 minutes, 33 seconds to reach a preliminary orbit. The restart of the RL10 engine is scheduled near 67 minutes after takeoff for a range of three and a half minutes to inject the satellite into an egg-shaped transfer orbit of between 1,200 kilometers (1245 km and 185 kilometers) above the Earth, with its orbital plane inclined 55 degrees to the equator.

The GPS satellite built by Lockheed Martin will separate the Delta 4 launcher at T + plus 1 hour and 55 minutes.

The GPS navigation satellite 3 SV02, nicknamed "Magellan", will use its own engine to go around its orbit and join the GPS constellation located about 12,550 kilometers above the planet. member of the constellation.

The GPS network provides positioning and synchronization services worldwide to civilian and military users, issuing signals supported by airliners, ATMs, drivers, and smart bombs, among others. many other users.

The satellite to be launched Thursday is the second of a new generation of GPS satellites, offering more precise navigation signals and a longer life. The new satellites are also compatible with other space navigation networks operated by Europe, Japan and China.

The first of the new series of spacecraft GPS launched in December aboard a SpaceX Falcon 9 rocket.

Photo archive of a Delta 4-Medium rocket on the launch pad before a previous mission. Credit: United Launch Alliance

The launch of the Delta 4 on Thursday will be the last flight of the Delta 4-Medium rocket variant, which flies with a single-stage first thruster, with additional thrust provided by solid propellant propellants.

The configuration of the Delta 4-Heavy rocket, made by combining three Delta 4 rocket cores, will continue to fly in the 2020s. The National Reconnaissance Office, which uses the Air Force as a contracting agent, has concluded contracts for at least five other Delta 4-Heavy missions until 2024.

In 2014, ULA decided to remove the Delta 4-Medium configuration because it is more expensive than the company's Atlas 5 rocket. The two rocket families are also largely redundant, but ULA has kept the Atlas and Delta lines aligned so that the Air Force has two rocket options to send military charges into space.

There is no heavy variant of the Atlas 5 rocket. The Delta 4-Heavy will therefore continue to fly in the 2020s, until the Vulcan launcher of the next generation of ULA is operational.

The removal of the Delta 4-Medium rocket also marks the final flight of the Delta Delta 4's 4-meter (13.1-foot) fairing. The Delta 4-Heavy rockets are expected to launch within the next five years. all use a larger payload shroud of 5 meters (16.4 feet).

SpaceX's Falcon 9 and Falcon Heavy rockets are now certified to fly the Army's national security satellites, providing the Air Force with a second family of launchers alongside the Atlas 5 and Delta 4-Heavy.

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