Things didn’t go as planned today for Sir Richard Branson’s Virgin Orbit company. Branson seems to be in a glut recently. He recently needed to liquidate shares of the publically traded Virgin Galactic to shore up his other business hit hard by the COVID19 downturn in travel. The demo flight of the rocket didn’t make it to orbit, but it at least got partway there. Possibly the best news, nobody suffered injuries thanks to precautions taken by Virgin Orbit when the Self Destruct command initiated. First let’s look at how the system works and then better understand what happened.
Flight Termination Systems – how does it work?
Rockets get equipped with a self destruct device. If a rocket launch goes awry, the rocket becomes a hazard to people, property and equipment. Why destroy expensive rockets? Rockets contain highly combustible propellent and oxidizer. If left uncontrolled, the rocket potentially endangers populated areas by crossing pre-determined lines defining the flight launch corridor. The resulting explosion gets the unconsumed propellants and oxidizer to combust while within a prescribed zone of safety.
Although self destruct device sounds cool, the industry refers to it as Flight Termination System or “FTS”. FTS uses encrypted signals to ensure inadvertent activation doesn’t happen. The Range Safety Officer “RSO“ is accountable for Arming and issuing the final command to terminate the rocket.
The rocket is monitored during the launch sequence to ensure that it does not stray outside of the launch corridor. Even if the rocket appears to be headed for an unpopulated area with the remained propellent, if the rocket engines falters, it could stray into an inhabited area. Before the rocket exits the launch corridor, the RSO will end powered flight if liquid fueled. They shut the Engines down with the first signal received by the rocket. We cannot shut solid boosters down once ignited.
A second coded signal, ‘fire’, detonates explosives, designed to break open the propellant tanks open and disperse their contents. This works for both solid and liquid fueled rockets.
Range safety requirements limited the number of launches per year. Each launch required resources and equipment keenly focused on the launch to ensure safety. Two companies sought to develop an improved version of range safety.
Autonomous Flight Termination System
NASA began experimenting with flight termination systems which did not require human intervention. NASA maintained an AFTS engineering development team since 2000, tasked with developing the technology. The development extended in 2002 with the DoD partnership with the DoD under the joint NASA/USAF Advanced Range Technologies Working Group. The working group aimed to reduce the access cost to space through the development of an AFTS system available for use by all ITAR approved Range Users. Since the inception of the program, 40 or more U.S. Companies and U.S. Federal Agencies received the technical transfer.
In the 2000s developments by ATK* and SpaceX sought improvements on the system. Both companies developed autonomous flight termination AFTS. AFTS uses a GPS-aided, computer-controlled system to monitor and end an off-nominal flight. This automated approach provided greater control of missions and reduces dependency on human staff. The Concept of AFTS is straightforward. A box on the vehicle (AFTU) receives and processes data from GPS and INS sensors. The system needs a built-in pre-flight period. In the event a rule violation occurs, the flight termination swiftly happens without human intervention.
SpaceX and ATK* have both demonstrated the AFT functionality. In August of 2014 SpaceX used an AFT system on a Falcon 9 prototype booster(F9R Dev1). When the F9R Dev1 test booster experienced a flight anomaly during a test flight, the booster’s control system issued a command to terminate. The vehicle self-destructed in the air over within the prescribed area near McGregor, Texas. A statement from SpaceX explained what happened: “Earlier today, in McGregor, Texas, SpaceX conducted a test flight of a three-engine version of the F9R test vehicle (successor to Grasshopper). During the flight, an anomaly was detected in the vehicle and the flight termination system automatically terminated the mission.”
(Read more details on here: https://www.gps.gov/cgsic/meetings/2019/valencia.pdf)
* note *ATK Merged with Orbital Sciences Corporation to form Orbital ATK, Orbital ATK bought by Northrop Grumman in 2018. ATK’s Autonomous Flight Safety System made its debut on November 19, 2013 during a test flight at NASA’s Wallops Flight Facility.
Virgin Oribit’s May 2020 Launch
Even though the rocket exploded, Virgin Orbit shared some good news. They reported the company successfully conducted all of its pre-launch procedures, the captive carry flight out to the drop site, gain a clean telemetry lock from multiple dishes, a smooth pass through the racetrack, terminal count, and a clean release. After being released from the carrier aircraft, the LauncherOne rocket successfully lighted up the booster engine. This was the first time the company attempted an in-air ignition.
Here’s a quick shot from takeoff. pic.twitter.com/7nt1u58ogs
— Virgin Orbit (@Virgin_Orbit) May 25, 2020
As with many other firsts, things go wrong. Virgin Orbit reported an anomaly that occurred early in the flight of the 75,000 lbf thrust first stage. Unfortunately the anomaly exceeded the mission rules safely. Although Cosmic Girl can potentially take off from thousands of airports, any rocket( air-launched included) must meet rigorous safety standards. Virgin Orbit uses its fully automated flight safety truly unlocks the flexibility only an air-launched system can deliver. The system allows for expanding its portfolio of launch locations.
The carrier aircraft Cosmic Girl and all of its crew landed safely at Mojave Air and Space Port, concluding the mission. Elon Musk even shared a tweet of support retelling his experience of four launch attempts prior to success.
CEO of Virgin Orbit, Dan Hart, shared uplifting feedback regarding the launch attempt: “Our team performed their pre-launch & flight operations with incredible skill today. Test flights are instrumented to yield data and we now have a treasure trove of that… we took a big step forward today.”
The company’s next rocket is in the last stages of integration. The companies Long Beach manufacturing facility houses a half-dozen other rockets for subsequent missions not far behind in the assembly process. Virgin Orbit’s decision to begin production of multiple rockets before this test flight enables the team to progress to the next attempt at a significantly faster pace, shortly after making any necessary modifications to the launch system.
More about the Virgin space companies
In case someone remains confused about the relationship of the Virgin space companies, although Virgin Galactic is publically traded, Virgin Orbit and The Spaceship Company are not. Virgin Orbit is a vertically integrated aerospace company. Sir Richard Branson’s Virgin Group started Virgin Orbit along with the other sister companies, The Spaceship Company and Virgin Galactic. While Virgin Galactic aims to bring people into space, Virgin Orbit looks to bring small satellites there. The miniaturization of satellites ushers in a new era of space capabilities. New approaches for the launch of these smaller satellites continue to develop. Virgin Orbit aims to offer an agile and affordable launch service fit for the smaller satellites. The California-based satellite launch company website highlights the capability of an All American made rocket launching dedicated SmallSat missions.
