Screenshot from ULA Webcast of the launch of CST-100 Test 2. It better work this time
Mission Rundown: ULA - Atlas V N22 - OFT-2 - CST-100
Written: November 27, 2022
Reset your clocks. We fly again
Boeing’s Starliner spacecraft has launched on its Orbital Flight Test 2 mission atop a United Launch Alliance Atlas V rocket Thursday. OFT-2 departed Space Launch Complex 41 at Cape Canaveral at 18:54:47 EDT (22:54 UTC), to the International Space Station.
Orbital Flight Test 2, or OFT-2, is a repeat of Starliner’s 2019 OFT mission, now also known retrospectively as OFT-1. An uncrewed test of the Starliner spacecraft, developed by Boeing for NASA’s Commercial Crew Program (CCP), the original OFT had been intended as the last test before NASA entrusted astronauts on a Crewed Flight Test (CFT).
Due to the original OFT’s failure to complete a number of key objectives, including rendezvous and docking with the International Space Station, the OFT-2 mission was added ahead of the first crewed flight.
Starliner is one of two spacecraft developed to carry astronauts to and from the International Space Station under NASA’s Commercial Crew Program. The OFT and CFT missions conclude the development and demonstration phase of this program, paving the way for future crew rotation flights to the station. SpaceX has already completed these milestones with their Crew Dragon spacecraft, the other vehicle built for this program, which is currently undertaking its fourth long-duration crew mission to the ISS.
Major events during launch - Centaur MECO - Starliner separation - Centaur blowout - In the dessert it says Starliner orbit insertion - Red areas are NOTAM rocket part debris fields
OFT-2 marks the first flight of Starliner spacecraft number 2, which has not yet been named. Spacecraft number 3, now named Calypso, carried out the original OFT mission and is now expected to fly again for the CFT when Starliner carries its first crew.
To launch Starliner, Boeing has partnered with United Launch Alliance (ULA). The spacecraft rode atop a two-stage Atlas V N22 rocket, carrying it most of the way to orbit. Starliner then completed orbital insertion using its own propulsion systems before beginning a day-long chase to reach the International Space Station.
The rocket used on Thursday had tail number AV-085. For its 2021 launch attempt, OFT-2 was originally stacked atop AV-082, but after the delays to Starliner’s mission, the rocket was taken apart. The CCB flew with a single-engine Centaur as part of AV-096, which launched NASA’s Lucy mission last October, while AV-082’s dual-engine Centaur is now part of the AV-085 vehicle that has been tasked with deploying OFT-2.
In short hand AV-085 Atlas V flew with Centaur dual engine AV-082. Then AV-082 Atlas V got renamed AV-096 Atlas V together with Centaur single engine AV-096 and they flew with Lucy to look at some rocks in outer space. Confused. I am. Sort of.
Atlas V’s East Coast launch facility is Space Launch Complex 41 (SLC-41) at the Cape Canaveral Space Force Station. SLC-41 consists of a single launch pad, with rockets assembled atop a mobile launch platform in the nearby Vertical Integration Facility (VIF) before being moved into position for launch. SLC-41 was originally built for the Titan family of rockets, which it served until 1999 when it began conversion for Atlas. It will also be used by ULA’s forthcoming Vulcan rocket.
Starliner is currently expected to dock with the ISS at 19:10:24 EDT (23:10:24 UTC) on Friday – or 24 hours, 15 minutes, and 39 seconds mission elapsed time. It will dock at the forward port of the Harmony module, via Pressurized Mating Adaptor 2 (PMA-2) and International Docking Adaptor-Forward (IDA-F). Starliner will stay at the ISS for about four days before undocking to begin its return to Earth.
Following a deorbit burn, the capsule and service module will separate. The service module will burn up on reentry, while Starliner’s capsule will land at the White Sands Space Harbor in New Mexico. If the OFT-2 mission is completed successfully, Starliner’s next mission will be the Crewed Flight Test (CFT) when it will carry astronauts into orbit for the first time.
The Boeing CST-100 Starliner
The Crew Space Transportation 100 (CST-100), Starliner consists of a reusable capsule that can theoretically seat seven astronauts – although it will typically fly with up to four – and an expendable service module (SM).
Starliner is designed to spend up to 220 days in space docked to a space station and can operate for up to 60 hours in free flight.
Starliner itself is composed of two separate vehicles: the Crew Module and the Service Module. The Crew Module is equipped with 12 Reaction Control System (RCS) thrusters that can produce 100 lbf of thrust each.
The Service Module contains 28 RCS thrusters that produce 85 lbf thrust each and 20 Orbital Maneuvering and Attitude Control (OMAC) engines who produce 1,500 lbf thrust each. The Service Module’s OMAC engines will be used to perform abort maneuver during launch, the first crucial Orbit Insertion Burn after launch, all major in-orbit maneuvers, and the critical deorbit burn at the end of the mission.
The bottom of the Service Module contains the four Launch Abort Engines and all of the solar panels for power. For this OFT mission, the Launch Abort Engines will be disabled.
For OFT, Boeing and ULA did not want a miscalibration of the Emergency Detection System or a “miscommunication” between the system and Starliner to accidentally trigger an abort when nothing is actually wrong with the rocket.
In total, Starliner is capable of launching and landing seven people at the same time. This is largely driven by NASA’s desire for a full seven-person Station crew to pile into Starliner to quickly evacuate the Station if all crew happen to be on the U.S. side of the outpost if an emergency occurs.
Engineers breakdown of CST-100 in mayor parts - Note launch abort engines doubles as CST-100 orbit insertion engines after detachment from Centaur 2nd stage flying similar to a Shuttles ascent
A complement of four will be the normal crew rotation number, with Boeing having the option to sell a fifth seat to a private astronaut.
To accommodate this NASA requirement, Starliner has an internal pressurized volume of 11 cubic meters (390 cubic feet) for crew and cargo. 270 kg of ISS cargo being flown on this OFT mission. Most of it is food.
However, the OFT mission to the ISS – set for docking 25 hours after launch – docking with the ISS, by Friday. The rest of the mission went ahead as scheduled with ISS approach maneuvers in a lower orbit, before detaching and deorbiting itself for a landing in White Sands Space Harbour, New Mexico.
Boeing, in coordination with NASA and the U.S. Army, is working to return its CST-100 Starliner to land in White Sands, New Mexico, on Wednesday May 25. The deorbit burn is scheduled for 6:07 a.m. EDT, landing for 6:57 a.m. EDT - 22:49:00 UTC.
Timeline of Starliner’s descent from orbit to solid ground in the yellow line. Blue is free falling with the Forward Heat Shield. It would be a ballistic line. Red is the main heat shield’s descent line.
The forward heat shield has its own parachute, so the blue descent line makes sense now.
Starliner capsule no. 2 is expected to be refurbished and is currently expected to fly again on the first operational crew mission, which will follow the successful completion of the Crewed Flight Test 2 - CFT-2.
The launch Vehicle Atlas V N22
The Atlas V rocket will deliver Boeing’s CST-100 Starliner spacecraft to a 98-nautical mile (nmi) sub-orbital trajectory. Following separation from the Atlas V, the Starliner engines will propel the spacecraft to its final orbit and on to the ISS.
Modified specifically for the Boeing CST-100 Starliner spacecraft, the Atlas V Starliner configuration does not include a payload fairing. Instead, the Starliner’s own protective surfaces take the place of the fairing to protect the uncrewed spacecraft during ascent. This is the inaugural flight of this configuration.
The Atlas V N22 rocket stands 52.4 meters - 172 feet tall on SLC-41. The Orbital Flight Test will be the 81st launch of the Atlas V and will mark ULA's 136th mission.
During the Wet Dress Rehearsal - WDR 25000 gallon of RP-1 kerosene was loaded into the main booster core - 1st stage where it remained until launch day.
There will be loaded 66000 gallon of cryogenic liquid oxygen and hydrogen in the three remaining tanks. Stage one fuel tank is already loaded with RP-1. First step is loading 4150 gallon of cryogenic liquid oxygen into the Centaurs LOX tank. Next, filling the first stage with 48800 gallon of cryogenic liquid oxygen in the core boosters LOX tank.
Atlas V N22 is split in its major parts. Without a standard fairing encapsulating the Centaur stage a special narrow Stub Adapter must be used. The Centaur is usually inside the 5 meter fairing
The Starliner attached to the Atlas V uses a launch vehicle adapter (LVA) which includes an aeroskirt to reduce aerodynamic loads on the vehicle. The Atlas V configuration for this mission is powered by dual Aerojet Rocketdyne RL10A-4-2 engines, each producing 22,600 lbs. of thrust. The Centaur 2nd stage also includes an Emergency Detection System (EDS) that monitors the health of the rocket throughout flight.
The second stage is the Centaur, a hallmark of the Atlas family that was first used in 1962. Since then, the Centaur has evolved into the Common Centaur used today. Recently to power the stage, an Aerojet Rocketdyne RL10C-1 engine is used to place its payload(s) into its final orbit. The RL10 engine is historic, having been used over several generations of rocket families and has been produced over 500 times.
The second flight of Atlas V is still in the N22 configuration (N = no fairing, 2 = two SRB’s, 2 = dual-engine bell Centaur). More boosters will give more lift, but the gravity loads on the crew inside would be exceeding 3.5 g. The restraints on Atlas V N22 caused by the gravity drag reduces its thrust and expands its flight time.
Meaning burning more fuel to beat the gravity drag which is gravity loads over time.
The only fault with those OTF missions was not to insert Starliner in a stable low earth orbit with the Centaur 2nd stage. Later missions could have fiddled with Space Shuttle flight profiles meaning incomplete suborbital launches, and using abort OMAC engines to circularize Starliners first orbit. They made it work this time.
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