Photo from SpaceX of USSF-52 on Launch Pad 39A. It’s dark soon, but bring sunglasses though
Mission Rundown: Falcon Heavy 9 - USSF-52
Written: December 29, 2023
The name: USSF-52 − The game: X-37B
SpaceX will be launching USSF-52 U.S. Air Force’s X-37B Orbital Test Vehicle (OTV) on its ninth mission on a Falcon Heavy rocket. FH9 is composed of a new block 5 center core B1084-1 and two flight proven side boosters; B1064-5 and B1065-5.
USSF-52 launched at 20:07 EST − 01:07 UTC on December 28/29, 2023. Falcon Heavy 9 will be lifting off from Launch Complex 39A at the Kennedy Space Center in Florida.
Graphic from Flight Club showing FH8’s ascent profile with booster separation, boostback, reentry and landing burns, while the core booster continues until MECO, stage separation and 2nd stage ignition. Fairing jettison, its recovery area and core booster crash site is located to the northeast
After burning for about 2 minutes and 29 seconds, the side boosters will separate from the core booster and return to Florida and land on LZ-1 and LZ-2 at CCSFS.
The core booster will keep burning for about 1 minute and 20 seconds before shutting down and separating from the second stage, which will continue burning until reaching orbit velocity and coast to the continent of Africa and the Equator.
The core booster will crash about 1500 Km downrange in the Atlantic Ocean. Compared to FH3 with STP-2 with its attempt to land on OCISLY some 1236 km downrange, that extra burntime gives a 21% increase in range and thereby performance of its payload.
The Falcon Heavy isn’t scheduled to fly more missions this year. The USSF-52 mission was scheduled for launch in June, but that was delayed and swabbed with the previous NASA Psyche asteroid probe mission, which was targeted for july.
Map from Raul based on the NGA notice. Side booster will land on LZ-1 and LZ-2. Fairing recovery area is 1543 km downrange. The Core booster crash site is only ~1500 km downrange
Photo of Falcon Heavy 9 viewed in details - A contemporary graphic picture can be found here
Falcon Heavy will have completed its ninth mission since the first testflight.
SpaceX did perform a static fire test of the Falcon Heavy 9 with USSF-52 at 12:00 EST on December 3, 2023 while waiting for its launch out of Cape Canaveral.
Falcon Heavy is constructed by joining of three Falcon 9 boosters side by side with a central long mission duration second stage carrying the payload into orbit.
The side boosters B1064 and B1065 will after detachment do a ‘boost back’ burn to Cape Canaveral. A re-entry burn will slow down the boosters and protect them from heating, and a landing burn to land the side boosters at Landing Zones 1 and 2, from where they will be made ready by minor refurbishments in preparations for their sixth flight.
The center core B1084-1 is flying bareback without landing legs; grid fins and using an old white interstage just like on the previous Falcon Heavy missions. The center core will be expended to offer additional performance to the military payload.
After second stage separation the Merlin vacuum engine ignited followed by the payload fairing separation. The second stage first burn will inject USSF-52 into a near-circular low-Earth 52.5o orbit. The second stage doesn’t have a mission extension package since the second stage is painted all white.
That extension package is a gray stripe, which helps keep the RP-1 warm in sunlight, an increased number of composite-overwrapped pressure vessels (COPVs) for pressurization control, and additional TEA-TEB canisters for 3-5 relights of the vacuum engine.
After a 46 minute long coast period halfway around the world, the Mvac’s second burn will turn and inject USSF-52 into a steeper 78.8o orbit. X-37B will after its deployment use its own onboard ion propulsion system to alter its orbit further on its 6-900 day journey.
FH9's second stage will deorbit from a steep 78.8o orbit which indicates it will perform a dogleg maneuver during the MVac second circularizing burn. The splashdown zone is in the Northeastern Pacific Ocean relatively close to the Canadian coastline.
The fairings are both new, flying for the first time on this mission, and will be recovered ~1543 km downrange by recovery vessel Doug, who will lift both fairings out of the water and sail them back for refurbishment. Recovery vessel Doug is named after Demo-2 Astronaut Doug Hurley.
The USSF-52 Payload
The purpose of this spacecraft is highly uncertain due to the classified nature of the mission. However, it is known that this mission will carry USSF’s Seeds-2 mission, which will expose plant seeds to harsh radiation environments of a long spaceflight.
Additionally, this mission USSF-52 will deploy FalconSat-8 — a small satellite developed by the United States Air Force Academy that will test technologies and perform scientific investigations in orbit. Further details on this mission are unknown.
Boeing X-37
The Orbital Test Vehicle (OTV), is a reusable robotic spacecraft. It is boosted into space by a launch vehicle ‘rocket’, it re-enters Earth's atmosphere and lands as a spaceplane.
The X-37 is operated by the United States Space Force, and was previously operated by Air Force Space Command until 2019 for orbital spaceflight missions intended to demonstrate reusable space technologies.
The X-37 began as a NASA project in 1999, before being transferred to the United States Department of Defense in 2004.
The X-37 first flew during a drop test in 2006; its first orbital mission was launched in April 2010 on an Atlas V rocket, and returned to Earth in December 2010. Subsequent flights gradually extended the mission duration, reaching 780 days in orbit for the fifth mission, the first to launch on a Falcon 9 rocket. The latest mission, the sixth, launched on an Atlas V on 17 May 2020 lasting a record breaking 908 days.
A pair of X-37B going inside a 5 meter Atlas V 501 payload fairing and SpaceX standard fairing
The aerodynamic design of the X-37 was derived from the larger Space Shuttle orbiter, hence the X-37 has a similar lift-to-drag ratio, and a lower cross range at higher altitudes and Mach numbers compared to DARPA's Hypersonic Technology Vehicle.
An early requirement for the spacecraft called for a total mission delta-v of 7,000 miles per hour (3.1 km/s) for orbital maneuvers. An early goal for the program was for the X-37 to rendezvous with satellites and perform repairs.
The X-37 was originally designed to be carried into orbit in the cargo bay of the Space Shuttle, but underwent redesign for launch on a Delta IV or comparable rocket after it was determined that a shuttle flight would be uneconomical.
The X-37 was transferred from NASA to the Defense Advanced Research Projects Agency (DARPA) on 13 September 2004. Thereafter, the program became a classified project. DARPA promoted the X-37 as part of the independent space policy that the United States Department of Defense has pursued since the 1986 Challenger disaster.
The X-37 Orbital Test Vehicle is a reusable robotic spaceplane. It is an approximately 120-percent-scale derivative of the Boeing X-40, measuring over 29 feet (8.8 m) in length, and features two angled tail fins. The X-37 launches atop an Atlas V 501 or a SpaceX Falcon 9 rocket. The spaceplane is designed to operate in a speed range of up to Mach 25 on its re-entry.
The technologies demonstrated in the X-37 include an improved thermal protection system, enhanced avionics, an autonomous guidance system and an advanced airframe. The spaceplane's thermal protection system is built upon previous generations of atmospheric reentry spacecraft, incorporating silica ceramic tiles. The X-37's avionics suite was used by Boeing to develop its CST-100 crewed spacecraft.
The development of the X-37 was to "aid in the design and development of NASA's Orbital Space Plane, designed to provide a crew rescue and crew transport capability to and from the International Space Station", according to a NASA fact sheet.
The X-37 for NASA was to be powered by one Aerojet AR2-3 engine using storable propellants, providing thrust of 6,600 pounds-force (29.4 kN). The human-rated AR2-3 engine had been used on the dual-power NF-104A astronaut training vehicle and was given a new flight certification for use on the X-37 with hydrogen peroxide/JP-8 propellants. This was reportedly changed to a hypergolic nitrogen-tetroxide/hydrazine propulsion system.
Also featured in this launch is the Aerojet Rocketdyne's XR-5A Xenon Gas Hall Effect Thruster, which is replacing one of the original Aerojet AR2-3 engines. Compared to chemical engines, the thrust is very small, on the order of 83 mN for a typical thruster operating at 300 V, 1.5 kW.
For comparison, the weight of a coin like the U.S. quarter or a 20-cent Euro coin is approximately 60 mN. As with all forms of electrically powered spacecraft propulsion, thrust is limited by available power, efficiency, and specific impulse.
The X-37 lands automatically upon returning from orbit and is the second reusable spacecraft to have such a capability, after the Soviet Buran shuttle. The X-37 is the smallest and lightest orbital space plane flown to date; it has a launch mass of around 11,000 pounds (5,000 kg) and is approximately one quarter of the size of the Space Shuttle orbiter. - Wikipedia.
Falcon Heavy rocket
SpaceX photo of FH3 STP-2 hanging under the loft cranes in the Horizontal Integration Hangar
Falcon Heavy stands 70 meters tall, weighs about 1.4 million kg at liftoff, and produces a thrust of approximately 22,241 kN from its 27 Merlin 1D engines. The rocket is capable of delivering 63.8 tonnes to low Earth orbit and 26.7 tonnes to geostationary transfer orbit.
Falcon Heavy is a partially reusable heavy-lift launch vehicle designed and manufactured by SpaceX. It is derived from the Falcon 9 vehicle and consists of a strengthened Falcon 9 first stage as the center core with two additional Falcon 9-like first stages as strap-on boosters. Falcon Heavy has the highest payload capacity of any currently operational launch vehicle, and the third-highest capacity of any rocket ever to reach orbit, trailing the Saturn V and Energia.
The combined thrust of the Falcon Heavy 27 Merlin 1D# is 2/3 of the first stage thrust of the five F1 engines on the Saturn V rocket that lifted mankind through the atmosphere on its way to the Moon. This means that Falcon Heavy is almost capable of a Lunar mission like the Apollo Saturn V was. Two launches of Falcon Heavy should be able to do it.
Falcon Heavy consists of a structurally strengthened and therefore heavier Falcon 9 as the "core" component, with two additional Falcon 9 first stages without interstages but with nose cone acting as liquid fuel strap-on boosters, which is conceptually similar to Evolved Expendable Launch Vehicle (EELV) Delta IV Heavy launcher.
The rocket was designed to meet or exceed all current requirements of human rating. The structural safety margins are 40% above flight loads, higher than the 25% margins of other rockets. The Falcon 9 tank walls and domes are made from Aluminium–lithium alloy. SpaceX uses an all-friction stir welded tank. Falcon Heavy was designed from the outset to carry humans into space and it would restore the possibility of flying crewed missions to the Moon or Mars.
The interstage, which connects the upper and lower stage for Falcon 9, is a carbon fiber aluminum core composite structure. Stage separation occurs via reusable separation collets and a pneumatic pusher system. The second stage tank of Falcon 9 is simply a shorter version of the first stage tank and uses most of the same tooling, material, and manufacturing techniques. This approach reduces overall costs during production.
The Falcon Heavy includes first-stage recovery systems, to allow SpaceX to return the first stage boosters to the launch site as well as recover the first stage core following landing at an Autonomous Spaceport Drone Ship barge after completion of primary mission requirements. These systems include four deployable landing legs, which are locked against each first-stage tank core during ascent. Excess propellant reserved for Falcon Heavy first-stage recovery operations will be diverted for use on the primary mission objective, if required, ensuring sufficient performance margins for successful missions.
The nominal payload capacity to a geostationary transfer orbit (GTO) is 8,000 kg (18,000 lb) with recovery of all three first-stage cores versus 26,700 kg (58,900 lb) in expendable mode − They all get expended downrange. The Falcon Heavy can also inject a 16,000 kg (35,000 lb) payload into GTO if only the two boosters are recovered.
The second stage isn’t painted partial gray to prevent the RP-1 from freezing solid during the several hours long transfer trip to its geostationary orbit position. The Sun’s heat will not easily be reflected by the gray paint thus transferring surface heat to the RP-1.
After the deployment there will probably be enough propellant in the second stage tanks to deorbit. The ninth Falcon Heavy second stage won't be one of the more than 35 large pieces of space debris that will take eons to deorbit on its own.
2nd stages used on GTO missions usually remain in the highly elliptical transfer orbit with a perigee just a few hundred km above the Earth. The low perigee means it experiences significant drag and the orbit will decay within a year or two, until it reenters.
The 2nd stage is with its avionics package in itself a satellite bus, what's missing is solar panels for power supply, gyroscopes for orientation, various military/science instruments and maybe even Hall effect thrusters to perform maneuvers.
FH9's second stage will deorbit in the Northeastern Pacific Ocean parallel to the Canadian coastline after passing over Alaska.
SpaceX is the first entity ever that recovers and reflies its fairings. After being jettisoned, the two fairing halves will use cold gas thrusters to orientate themselves as they descend through the atmosphere. Once at a lower altitude, they will deploy drogue chutes and parafoils to help them glide down to a soft landing for recovery.
Lately it’s apparent that the fairings are actively being aiming for the droneship in order to speed up the recovery process and cut corners of the time table. The fairing is actively breaking its speed and turning back before deploying its parachute at the last moment.
Another solution is a ‘vertical’ boost lifting the fairings apogee so the ballistic trajectory is changed aiming for a landing nearer the droneship. It’s equivalent to raising the angle on a water hose giving the water stream an higher arc but giving it a shorter reach.
It’s not clear whether or not the cold gas nitrogen thrusters alone are capable of doing a ‘boost back’ or a ‘push up’ so the fairings can alter their forward momentum mid-flight.
There are three known types of 34 x 17 foot fairings used by SpaceX to protect payload during ascent through the atmosphere. The first type had 10 evenly spaced ventilation ports in a circle on the bottom part of the fairings. This type was not aerodynamic enough to carry a parachute and ACS - Attitude Control System.
The aerodynamic balance during descent must have made them prone to stalling, or they burned up too easily. ACS gas tanks, flight orientation computers and ACS thrusters must have helped with these problems during development of type 2 fairings.
Comparison of Type 1 and 2 with measurements based on pixels - Type 2 are 5-6 inches thicker
The second type is a slightly thicker fairing with only 8 evenly spaced ventilation ports in a circle on the bottom part of the fairings. The ventilation ports release the pressurized Nitrox gas during ascent, but let seawater in which makes it harder to refurbish the fairings after recovery from the ocean.
The new third type has 8 ventilation ports in pair’s near the edge of the fairings. Some old type 2 fairings have been rebuilt and reused in Starlink launches. That have been a test program to develop the type 3 fairings to prevent saltwater from the ocean from flooding and sinking the fairing, and makes refurbishment toward the next flight easier.
Falcon fairings halfs have been recovered and reused since 2019. Improved design changes and overall refurbishment procedures have decreased the effects of water landings and led to an increased recovery rate of fairings.
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