Delta 4 Medium Makes Penultimate Launch

John Kraus photos
A great image taken by John Kraus of the Delta 4’s main booster and four smaller boosters, and the awesome power they produce. Visit his patreon to find more! Credit: John Kraus

Just after midnight, 00:23 UTC on March 16th 2019, a Delta 4 medium rocket placed a US military network relay satellite into orbit. Launching from Space Launch Complex 37B at Cape Canaveral AFB in Florida, the 66 meter tall Delta 4 is nearing retirement, with this being its second to last launch. After several technical issues, the ground teams eventually got the rocket and the satellite tracking network functioning correctly. The hydrogen fueled RS-68A main engine ignited moments before liftoff for 5 seconds before the hold down bolts released at T-0, firing away with 1.8 million pounds of thrust. This mission has extended ULA’s streak of successful missions to 133 since its inception in 2006.

Marcus Cote
Maybe the photo of the night by Marcus Cote, showing the huge exhaust plume created by the Delta 4 in 5, 4 configuration. Credit: Marcus Cote
marcus cote
A great time lapse of the Delta 4 launching WGS10 satellite into a geostationary orbit. Credit: Marcus Cote.

The rocket veered towards an easterly direction over the Atlantic Ocean, aiming to place the communications satellite to its final operating position 36,000 km (22,000 miles) above the equator in geostationary orbit. The solid rocket boosters burned out and were jettisoned in pairs roughly 1 minute and 40 seconds into flight. The main engine continued to fly on until 4 minutes in when the first stage was cut off, and then released shortly after. The first stage then fell back to Earth into the Atlantic Ocean. The upper stage was powered by a RL10B-2 engine, made by Aerojet Rocketdyne, the same manufacturers of the main engine. The upper stage engine ignited twice to push the satellite into an elliptical transfer orbit. The satellite separated from the second stage at T+36 minutes 50 seconds.

ULA
An image showing the scary power of the rocket boosters at liftoff, the rocket firing 1.8 million pounds of thrust into the ground trying to escape the Earth. Credit: ULA.

On board was the WGS 10 military communications satellite. It is a 6000kg (13,200 lb) broadband satellite, that is joining nine others that have been slowly placed in orbit since 2007. The idea is to form a globe spanning network that can relay video, data and other useful information between the battlefield and the headquarters, wherever they may be. The WGS fleet transmits both classified and unclassified information, and supports the US and its allies. On board is a digital channelizer that allows the satellite to relay signals using high data-rate X-band and Ka-band frequencies during its 14 year expected life. All of the WGS satellites were launched on ULA rockets, with the first two on Atlas V’s and all the rest on Delta 4’s. This mission had an estimated price tag of $400 million.

Glen Davis
An almost artistic image of the Delta 4 medium launching. Heavily edited, but still capturing that raw power. Credit: Glen Davis

Marking the second to last flight of the Delta 4 Medium variant rocket, it is noticeable as only having a single first stage core, whereas the Delta 4 Heavy has three. ULA are retiring certain areas of their launch family as they plan to debut the new Vulcan booster soon which will apparently be cheaper than their current offering. The decision to halt selling of the Delta 4 medium flight was made in 2014, but this and the next launch were already on the books at that time. The Delta 4 medium is apparently more expensive than the Atlas V launcher, but with a similar launch capability, leading to the reason for retirement. ULA described it as it being cheaper to run a few launchers more frequently than many launchers sporadically. The bigger Delta 4 heavy will continue to launch heavier payloads well into the mid 2020’s. Another reason for keeping the Delta 4 Medium was to allow the US military to have two choices to launch their payloads, that and the Atlas V. Now that the Falcon 9 is cleared to fly military satellites there is less need for the Delta variant.

marcus cote
The Delta 4 sitting on the pad, ready to launch the WGS10 satellite. Taken close up by Marcus cote the day before when setting up the remote cameras for the launch. Credit: Marcus Cote.
mike seely
A behind the scenes photo of setting up cameras before the launch. Credit: Mike Seeley.

Thank you for reading, take a look at my other posts if you are interested in space, electronics, or military history. If you are interested, follow me on Twitter to get updates on projects I am currently working on.

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Roundup: Parker Solar Probe Launch

Rocket flames
An awesome image of the Delta IV heavy launching from pad 37B. Credit: Aerojet Rocketdyne.

At 07:31 UTC on August the 12th 2018 the 10th ever Delta IV heavy vehicle launched the long awaited Parker Solar Probe from Cape Canaveral Space Launch Complex 37B. The Delta 4 Heavy launched PSP towards a heliocentric orbit. The mission aims to “touch the sun”, and to get as close to the sun as man has ever been. Getting as close as 3.9 million miles from the sun, that’s roughly 4% of the distance between the Earth and the Sun (roughly 93 million miles).

time lapse
A great timelapse of the Delta 4 heavy launching towards the sun. Credit: Marcus Cote.

The Parker Solar Probe was named after Dr Eugene Parker who discovered the solar winds in 1958. He was present at the launch at the Kennedy Space Centre, seeing the 685kg spacecraft lifted. The 7 year mission will make 24 elliptical orbits of the sun, and uses 7 flybys of Venus to drop the low point of the orbit. It will make the closest point of the orbit closer than any other man made object in heliocentric orbit. It will enter the sun’s “atmosphere”, a section known as the corona, the outermost part of the atmosphere. Protected by a 4.5 inch sunshield, it can withstand temperatures of 2500F (1377C). The aim is to understand how the sun can creates and evolves solar flares and solar winds. It is to understand how the highest energy particles that pass the Earth are formed. It is hoped that it will revolutionise our understanding of the sun, to help us develop and create technology here on Earth.

The rocket has three RS-68A boosters, with the outbound boosters cutting off at T+3 min 57 sec, the core then cut off a minute and a half later at T+5 min 36 sec. The Delta’s cryogenic first stage engine was RL10B-2, which began burning at T+5 min 55 sec, and stopped its first burn at T+10 min 37 sec. This burn entered the 3,044 kg load into a 168 km x 183 km x 28.38 deg parking orbit. The second burn started at T+22 min 25 sec, and ended at T+36 min 39 sec, accelerating it to C3 of 59 km2/sec2, roughly 5,300 m/s out of LEO. At this point the Probe was in solar orbit, the Star 4BV separated at T+37 min 9 sec, with it firing at T+37 min 29 sec. The burn ended a minute and a half later at T+38 min 58 sec, accelerating it to 8,750 m/s beyond LEO. The Parker Solar Probe separated four and a half minutes later. The orbits after this point become much more complicated to get to the prefered orbit touching the sun.

Engineers at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, work on NASA’s Parker Solar Probe spacecraft. Parker Solar Probe will be the first-ever mission to fly directly through the Sun’s atmosphere. Photo & Caption Credit: NASA / JHU-APL

The Delta 380 was the first Cape Canaveral Delta to use the upgraded “common avionics” system for its flight controller. The rocket was shipped to the Cape over a year ago, with it being assembled in the SLC 37 HIF. The rocket was then rolled out to the pad in April 2018, and there was a wet dress rehearsal on June 2 and 6th. The initial date for launch was the day before, august 11th but it was scrubbed at T-1 min 55 sec. Some of the best images of these launches are now taken by amateurs. I usually post a few of the images, but this launch was different as most of those who placed their cameras just a few hundred feet from the rocket got very damaged equipment.

Thank you for reading, take a look at my other posts if you are interested in space, electronics, or military history. If you are interested, follow me on Twitter to get updates on projects I am currently working on.

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