Screenshot from NASA Webcast of Parker Solar Probe. The minute they let go. You jump up
ULA - Delta IV Heavy - Parker Solar Probe
Written: September 28, 2021 - Edit: November 30, 2022
Let’s get one hell of a Suntan
A mission nearly 60 years in the making has launched on a historic flight to become the first spacecraft to “touch the surface of the Sun”.
NASA’s Parker Solar Probe, named after Dr. Eugene Parker, will unlock many of the mysteries still held by our solar system’s Star. The probe launched atop a United Launch Alliance Delta IV Heavy rocket on Sunday from the Cape’s SLC-37.
This was the 10th launch of a Delta IV Heavy at 03:31 EDT on August 12, 2018.
NOTAM with three splashdown areas. A is launch failure. B is Delta side boosters plus fairing parts and C is the main Delta booster core. There is no 2nd stage splashdown area specified.
A series of three Wet Dress Rehearsals were undertaken by the United Launch Alliance team for this particular Delta IV Heavy rocket in an attempt to ferret out any ground and vehicle issues that required attention and fixing prior to the scheduled launch.
Only the third WDR was successful, and a Mission Dress Rehearsal earlier this week and a final Flight Readiness Review all cleared the rocket and payload for launch.
After liftoff, Delta IV Heavy pitched downrange and headed due east over the Atlantic Ocean. Shortly after liftoff, the center core of the three Common Booster Cores (CBCs) of the first stage throttled back to conserve propellant.
After the second DCSS engine cutoff, the 2nd and 3rd stages separate – with the Northrop Grumman-built third stage, the STAR 48BV. This is a solid propellant stage that produced 17,490 lbs of thrust for just 84 seconds. But in that 84 seconds, the third stage imparted two-thirds of the total velocity of the launch phase.
(Of note, this is not the only part of the Delta IV Heavy built by Northrop Grumman. The first stage engine nozzles, pressurization tanks, payload fairing, and most of the white areas on the rocket are all built by Northrop Grumman.)
The specific mission parameters that call for Parker Solar Probe to make 24 close flybys of the Sun require a very specific trajectory and orbit. When Earth is moving around the Sun (and taking Parker with it), Parker Solar Probe actually has to start slowing down (relative to the Sun) during the powered phase of launch.
This sounds contradictory to what we generally think of for launches, but part of the job of the third stage, in this case, is to start that slowing down process.
During launch, the third stage’s velocity will increase because the speed relative to Earth is increasing. But, in fact, the velocity relative to the Sun is slowing down. This slow down burn will allow the Sun’s gravity to begin pulling Parker Solar inward toward Venus.
Once that small duration burn was complete, Parker Solar Probe separated from the third stage and was on its inward dive toward Venus.
Graphic with two spacecrafts paths to the Sun and Pluto both from Earth in a roundabout way
Parker Solar Probe will then execute seven gravitational assist flybys of Venus, first on 2 October 2018, so that it can perform progressively closer and closer flybys of the Sun’s surface – perihelion at 35.7 Sun Radii – on 5 November 2018. - Sun Radius?
These progressively closer orbits are achieved by the probe’s interactions with Venus, which slow Parker Solar down (the slower you go, the closer you get to the Sun’s surface due to the Sun’s gravitational forces) and gives some of its energy to Venus in the process.
Graphic of the Parker’s orbit trajectory between Venus and the Sun. RS is Sun Radii - Sun Radius
The Parker Solar Probe
Because United Launch Alliance has built up the reputation over the past few decades of being an incredibly reliable launch provider, they can often be trusted with high value payloads such as Mars missions, future piloted missions, and government contracts.
Keep in mind that the only purpose of ULA is to boost the Parker Solar Probe satellite into orbit. After it separates from the Delta Cryogenic Second Stage (DCSS), ULA no longer is in charge of the satellite and NASA takes over flight control.
Unlike other solar telescopes and missions, the Parker Solar Probe will venture where no probe has gone before – into the Sun’s corona. Mission planning calls for the probe to approach the Sun to within 6 million km (3.7 million miles) or just 0.04 AU – 8.5 solar radii.
Parker Solar Probe will seek to answer three very important questions about the Sun:
Why and how is the solar wind accelerated to supersonic speeds inside the corona?
What is the mechanism that heats and accelerates particles in the corona?
What is accelerating some particles, very few, to near the speed of light (creating highly energetic particles)?
Answering that third question holds potentially great significance for our lives here on Earth and our quest to move beyond Earth and out into the solar system because these highly energetic particles are highly charged and can penetrate walls of spacecraft and be harmful for astronauts – like giving them a constant x-ray.
These highly energetic particles can also wreak havoc with our electronics on Earth, in orbit, and in space. Therefore, part of Parker Solar’s mission is to help us better understand how the particles are accelerated/created in the corona – which in turn will help us better predict their occurrence and create improved plans for how to protect our technology and astronauts.
Graphic: Parker Solar Probe in 3rd stage burn slowing it down relative to the Earth’s orbit speed
In order to survive the intense environment of the outer corona, an area in which the probe will experience solar intensity 520 times greater than Earth does, a specialized heat shield and cooling system were designed to protect the spacecraft and scientific instruments.
The heat shield (or solar shadow-shield), which was installed for integrated vehicle testing in September 2017 at the Johns Hopkins Applied Physics Lab (APL), is made of reinforced carbon-carbon composite.
Reinforced carbon-carbon is most widely and infamously known for its use on the Space Shuttle, as the nose cap and Wing Leading Edge elements of the Thermal Protection System on the five Orbiters – though it was initially developed for the nose cones of intercontinental ballistic missiles and is currently used in the brake systems for Formula One racing cars.
For Parker Solar Probe, reinforced carbon-carbon will serve as the solar shadow-shield, which will block direct radiation from the Sun for the probe’s instrumentation and experiment packages and will keep temperatures behind the shield at a comfortable 85°F (29.4℃) while temperatures on the Sun-facing side of the shield will soar to 2,500°F (1,377℃) during closest approaches
While the surface of the solar shadow-shield will reach temperatures in excess of 2,500°F, the specially designed cooling system for the solar arrays will keep the arrays at a temperature of just 320°F or below.
This will be the first-of-its-kind actively cooled solar array system and was developed by APL in partnership with United Technologies Aerospace Systems (which manufactured the cooling system) and SolAero Technologies (which produced the solar arrays).
The cooling system itself is composed of a heated accumulator tank that will hold water (the coolant) during launch, two-speed pumps, and four radiators made of titanium tubes and aluminum fins just two hundredths of an inch thick.
Water was chosen as the coolant because of the temperature range the system will encounter throughout the mission. “For the temperature range we required, and for the mass constraints, water was the solution,” said Lockwood.
Mission update so far
March 3, 2022: As NASA's Parker Solar Probe completes its latest swing around the Sun, it's doing so in full view of dozens of other spacecraft and ground-based telescopes.
- These powerful instruments can't actually see Parker itself – the van-sized spacecraft is far too small for visible detection – but they offer from a distance what the probe is sensing close-up, as it samples and analyzes the solar wind and magnetic fields from as close as 5.3 million miles (8.5 million km) from the Sun's surface.
- Occurring at 10:36 a.m. EST (15:36 UTC) on Feb. 25, this was the 11th close approach – or perihelion in the spacecraft's orbit around the Sun – of 24 planned for Parker Solar Probe's primary mission. Most of these passes occur while the Sun is between the spacecraft and Earth, blocking any direct lines of sight from home. But every few orbits, the dynamics work out to put the spacecraft in Earth's view – and the Parker mission team seizes these opportunities to organize broad observation campaigns that not only include telescopes on Earth, but several spacecraft as well.
- More than 40 observatories around the globe, including the recently commissioned Daniel K. Inouye Solar Telescope in Hawaii, among other major installations in the southwestern United States, Europe and Asia, are training their visible, infrared and radio telescopes on the Sun over the several weeks around the perihelion.
A dozen spacecraft, including NASA's STEREO, Solar Dynamics Observatory, TIMED and Magnetospheric Multiscale missions, ESA's and NASA's Solar Orbiter, ESA's BepiColombo, the JAXA-led Hinode, and even NASA's MAVEN at Mars are making simultaneous observations of activity stretching from the Sun to Earth and beyond.
- The pass also marked the midway point in the mission's 11th solar encounter, which began Feb. 20 and continues through March 2. The spacecraft checked in with mission operators at APL – where Parker Solar Probe was designed and built – on Feb. 28 to report that it was healthy and operating as expected.
The Delta IV Heavy
One of the more powerful rockets currently in operation, the Delta IV Heavy has launched payloads including NROL satellites and the Parker Solar Probe, a mission to study the Sun. All of the previous Delta IV Heavy launches have been successful.
The Delta IV Heavy is a reliable heavy lift launch vehicle, meaning that it can take bigger and heavier payloads into orbit. It can launch up to 28,000 kg (61,000 lbs) to a 0 degree inclination from French Guiana, 14,000 kg (30,000 lbs) toward a Geostationary Transfer Orbit and on a 53 degree inclination in a Low Earth Orbit (LEO) towards ISS it lifts 25,980 kg (51,950 lbs). Be aware. ULA data must be confirmed from several sources.
And now from another source we hear this. Numbers? Who need them?
The Delta IV Heavy rocket stands 71 meters - 233 feet tall, is 16.15 - 53 feet wide and weighs 725.75 tons - 1.6 million pounds fully fueled. It will launch on 9.34 Mega Newtons - 2.1 million pounds of thrust from the three RS-68A main engines.
The Parker Solar Probe atop the launch vehicle is 2.98 meter - 9.8 feet tall, about 1 meter - 3.3 feet in diameter and has a mass of over 635 kilograms - 1,400 pounds.
Customers can choose between different payload fairing sizes to better optimize for their specific payload. Why choose something that tall to that short satellite?
To accommodate payloads of all sizes, ULA offers two different payload fairing heights both at 5 m (16 ft) wide. A 14 meter (47 ft) tall fairing and a 19.1 m (62.7 ft) tall fairing.
The Delta IV Heavy first stage consists of three nearly identical 40.8 meter boosters strapped together. Each booster has one RS-68A engine also manufactured by Aerojet Rocketdyne. The first stage is infamously known for lighting itself on fire just before launch to burn off extra hydrogen. It does this because it needs to get rid of any hydrogen so it does not explode unintentionally during liftoff.
The Delta IV Heavy first stage consists of three nearly identical 40.8 meter - 170 foot boosters strapped together. The Hydrogen and Oxygen tanks hold together 470 000 gallon of liquid propellant in 6 tanks measuring about 1 792 m3 in needed tank volume.
NROL-82 states that 120 000 gallons of liquid Oxygen is loaded. NROL-44 gave me these numbers. Second source found. Is 470 000 gallon of liquid propellant with DCSS +?
Each booster has one RS-68A engine also manufactured by Aerojet Rocketdyne. Together with DCSS and fairing they stand 71,6 meters - 235 feet tall on the launch pad.
Screenshot of Delta Heavy IV split in its major parts. The spacecraft is not Parker Solar Probe
The Hydrogen tanks hold 330 000 gallon of liquid Hydrogen chilled to -252,8 0C Celsius or -423 0F Fahrenheit in 3 tanks measuring about 1 254 m3 in estimated tank volume. The three Hydrogen tanks each hold at least 418 m3 cubic meter liquid Hydrogen.
The Oxygen tanks hold 120 000 gallon of liquid Oxygen chilled to below -182,96 0C Celsius or -297,33 0F Fahrenheit in 3 tanks measuring about 454,2 m3 in estimated tank volume. The three Oxygen tanks each hold at least 151,4 m3 cubic meter liquid Oxygen.
The first stage is infamously known for lighting itself on fire just before launch to burn off extra hydrogen. It does this because it needs to get rid of any hydrogen so it does not explode unintentionally during liftoff.
The hydrogen comes from the purging or chilling of the engines prior to ignition. The engine can’t handle the freezing chock of liquid Hydrogen and Oxygen and will split itself apart especially in the turbopump bearings. They will become brittle and shatter.
The hydrogen comes from the purging of the engines prior to ignition. Each RS-68A engine has the capability to produce 3,160 kN (705,000 lbf) of thrust for a combined 9,420 kN of total thrust. The RS-68A engine has a specific impulse of 362 seconds and burns liquid hydrogen (LH2) and liquid oxygen (LOx).
During the flight, the center booster burned at a slightly slower throttle setting than the two side boosters. This is because the Delta IV Heavy needs all three boosters in order to get enough velocity to pass through the thick parts of the atmosphere. However, after that, they are expended and jettisoned as to not carry any extra weight.
As the vacuum optimized second stage is very efficient, but not very powerful, the Delta IV Heavy burns its center booster longer than other rockets so the second stage will be able to put its payload into orbit.
Graphic demonstration of Delta IV Heavy’s cargo capacity is thanks to the DCSS boost. link
Continuing up the rocket comes the second stage. The Delta Cryogenic Second Stage (DCSS) is powered by a single, vacuum optimized RL10B-2 engine. For its fuel, the DCSS uses liquid hydrogen (LH2) and for the oxidizer, liquid oxygen (LOX).
The LH2 tank - volume of 38 m3 holding 10 000 gallon LH2 - being on top, has the job of supporting the payload and the payload fairing with a strut gage of two rings and is also structurally separated from the other ‘half’ of DCSS. The clearly smaller LOX tank - volume of 23 m3 holding 6 000 gallon LOX - is suspended in a strut gage of two rings below it and is responsible for structurally supporting the RL10B-2 engine.
The RL10B-2 was originally built by Aerojet Rocketdyne and first flew in 1998. It has the capability to produce 110 kN (24,700 lbf) of thrust in a vacuum and has a specific impulse of 462 seconds. It will light up at least four times with 18 minutes 15 seconds of burn time at an unknown throttle setting during the mission.
The RL10B-2 was originally built by Aerojet Rocketdyne and first flew in 1998. It has the capability to produce 110 kN (24,700 lbf) of thrust in a vacuum and has a specific impulse of 462 seconds. In order to save costs and weight, the gimbal system either uses battery powered or fuelcell powered electromagnetic actuators over normal hydraulics; this also increases reliability.
With the propellant already consisting of liquid hydrogen (LH2) and liquid oxygen (LOx) I suspect that pumping gasses through a fuel cell to produce electric power is more weight economical than a massive lithium battery pack. But what do I know about that?
CBC RS-68A Spin Start Pressurization is complete and the CBC helium bottles are at flight pressure. ??? The engine's turbo pumps fan blades are started with Helium gas pressure or liquid Helium forced through them from a ground supply pump. I guess.
Freakin Alphabet Soup. I’m choking here.
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