onsdag 20. juni 2018

Space - Virgin Orbit - Curt Lewis video

Virgin Orbit readies LauncherOne rocket for maiden flight

Virgin Orbit is just months away from the first launch of its LauncherOne rocket. The company is currently undergoing an extensive test campaign to ensure that the vehicle will function correctly on its maiden flight.

Virgin Orbit's mission is to make it easier for small satellites to reach orbit.

"Traditionally these [small] satellites went as back passengers with large satellites. If you were putting up a big communications satellite or you were putting up [a spacecraft] to supply the space station you could tag along," explained Virgin Orbit's CEO Dan Hart at the Western Museum of Flight earlier this year.

"It's a pretty efficient way to get to orbit in terms of cost because you are not paying for most of the rocket. You are just a passenger in the glove compartment. That works for experiments very well. It doesn't work that well if you have to get to a specific orbit at a specific time. As these companies or missions are growing up with small satellites, they are becoming demanding customers. These customers are just screaming for a dedicated service."

A graphic of the LauncherOne rocket. Credit: Virgin Orbit
To provide a dedicated service, Virgin has developed the LauncherOne rocket - a two stage small satellite launcher. The vehicle uses LOx for the oxidizer and RP-1 for propellant. Interestingly, unlike most rockets which launch from a stationary pad - LauncherOne will be released from beneath an airplane.

The aircraft which will be used to release the rocket is a Boeing 747-400 named Cosmic Girl. The plane was previously owned by Virgin Atlantic Airways.

Cosmic Girl will carry the rocket beneath her left wing. 747's were originally designed with the ability to ferry a fifth engine. Virgin Orbit has modified that location to support the rocket. During a mission, the fuel onboard the 747 will be redistributed to balance the aircraft, as LauncherOne is offset to one side.


LauncherOne and its carrier aircraft Cosmic Girl. Credit: Virgin Orbit
Due to the insulation on LauncherOne, LOx will not have to be conditioned during a flight. However, the aircraft has the capability to eventually service LOx which would enable longer flights.


Once Cosmic Girl is ready to launch LauncherOne, she will pitch upwards to at least 25 degrees. Then, Cosmic Girl will release the rocket. LauncherOne will fall for approximately 4-5 seconds before igniting the first stage.

The first stage of LauncherOne is powered by a single NewtonThree engine which will burn for about three minutes. NewtonThree has been optimized to take advantage of launching beneath an aircraft. As Hart explained, "We don't have to have our expansion ratio of our first stage chamber driven by sea launch, because we are going up from 35,000 feet."

The second stage utilizes a single NewtonFour engine. During standard missions, NewtonFour will perform multiple burns - totalling nearly six minutes in duration.

NewtonThree is capable of approximately 330 kilonewtons of thrust while NewtonFour is capable of roughly 22 kilonewtons of thrust.




Both engines are tested at Virgin Orbit's test facility near the Mojave Air and Space Port in California. Over recent months, the company has been performing numerous long duration burns in preparation for the maiden launch of LauncherOne.

Additionally, at the end of last year, Virgin completed the first LauncherOne vehicle. The milestone allowed for the teams to begin launch countdown rehearsals with the pathfinder in Mojave.

During the rehearsals, the rocket is mounted on a stand from the same attachment points used to mate the vehicle with Cosmic Girl. Then, the teams go through all the procedures leading up to T-0 including propellant load.

One major hurdle remaining in the test campaign is a captive carry test. This milestone will see Cosmic Girl carry a LauncherOne rocket during a flight. This test will validate that all systems work as expected when in the launch configuration. Preparations for the test are currently underway, and it is expected to occur in the coming weeks.

Once Virgin is ready to begin orbital launches, LauncherOne will initially operate out of the Mojave Air and Space Port. Cosmic Girl will fly from the desert out over the Pacific Ocean and then release LauncherOne in a southerly direction. The flight path will allow the rocket to serve customers going to polar or sun-synchronous orbits.


Virgin Orbit's plans for a mobile launch system. Credit: Virgin Orbit
While operations will start from Mojave, they will quickly expand to other sites. According to Virgin Orbit, LauncherOne "will operate from a variety of locations independently of traditional launch ranges - which are often congested with traffic - and will have the ability to operate through or around weather conditions and other impediments that delay traditional launches."

Some of the additional locations being looked at include the Shuttle Landing Facility at Kennedy Space Center and Kona International Airport in Hawaii. These options will expand the range of inclinations which LauncherOne can serve.

The payload capacity for LauncherOne is 300 kilograms when executing missions to a sun-synchronous orbit. When going to equatorial orbits, the payload capacity increases to 500 kilograms, as the vehicle can take advantage of Earth's rotation.

For now, Virgin Orbit will only perform missions to low Earth orbit. However, Hart stated, "We are considering higher orbits, and we have some interesting ideas that could get us to geosynchronous orbit or above."

A Pegasus XL rocket launches NASA's Cyclone Global Navigation Satellite System (CYGNSS) mission. Credit: NASA
Currently, the price of a LauncherOne launch is approximately $12 million. For comparison, NASA paid Orbital ATK (now Northrop Grumman Innovation Systems) $56.3 million to launch the ICON mission on a Pegasus XL rocket. Pegasus is the only air launch vehicle in operation and has a similar payload capacity to LauncherOne.

LauncherOne's manifest is filling up fast for a company that is yet to reach orbit. Virgin Orbit has signed a deal with the European Space Agency to launch the SITAEL satellite - a demonstration mission for a new electrical propulsion system. Similarly, NASA has ordered an ELaNa (Educational Launch of Nanosatellites) launch. Additionally, The US Department of Defense has awarded Virgin Orbit a launch contract through Virgin Orbit's VOX Space subsidiary which handles the national security market.

On the commercial front, GomSpace has ordered a launch for several nanosatellites which will track ships and planes. Cloud Constellation Corporation has signed a deal for 12 LauncherOne missions to deploy its SpaceBelt constellation. SpaceBelt will enable "space-based cloud storage data centers." And most impressively, OneWeb has signed a deal for 39 LauncherOne flights to deploy a portion of its internet constellation.

With such a large manifest, Virgin Orbit will have to quickly ramp up LauncherOne's flight rate. To make this possible, Virgin's 180,000 square foot factory in Long Beach California has several LauncherOne vehicles already under construction. According to Hart, "When we go to flight with our first rocket, we will have our second rocket there on the floor."

Concerning reusability which has been a hot trend in the space industry, Hart points out that "a 747 aircraft is as reusable as stage as you can have."

He went on to add, "on the rocket side, we are considering reusability options, and there are a number that we are looking at as we look at forward spirals.

"At this size with a single engine on each stage, we have to finish the tradeoff between the logistics associated with reusability and techniques like additive manufacturing."

For now, a successful test phase for the rocket in tandem with the carrier aircraft is the priority, which will pave the way to the system becoming operational for customer missions.

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