VSS Unity: Virgin Galactic Is Back

VSS unity Flight
VSS Unity during its first test flight. Credit: Virgin Galactic.

On Thursday 5th of April 2018, Virgin Galactic’s SpaceShipTwo conducted its first powered test flight of 2018. With very little in the media from Virgin Galactic recently, this has been a welcome development in the field of space tourism, and the development of space planes. Named the VSS Unity, this space plane is the newest development from the Spaceship Company.

USS Unity engine
USS Unity with an ignited engine rapidly accelerating into the sky. Credit: Virgin Galactic.

Virgin Galactic hasn’t performed a powered test flight since 31st of October 2014 when the VSS Enterprise experienced a catastrophic mid flight failure. The incident in the first of 5 planned SpaceShipTwo aircraft ended with a tragic accident which resulted in the death of one test pilot and serious injury to the other. With the program many years behind schedule, many critics thought this could have been the end for Virgin Galactic. Fortunately, Virgin Galactic have said the fault was not in the hardware, and was a change in safety procedure rather than a design overhaul. Over the last year, Virgin Galactic has made significant progress, leading to this powered test flight.

VSS Unity Gliding
VSS Unity, gliding back to earth after it has burnt all of the fuel, it can see the curvature of the earth. Credit: Virgin Galactic.

An NTSB investigation into the accident concluded that a pilot prematurely deployed the feathering system on the spacecraft. The system is used to increase drag during reentry. Many have criticised Scaled Composites (the manufacturer) and Virgin Galactic for not having fail-safe’s in place to prevent this problem. This is what lead into the review into the safety of the craft. After the loss of the USS Enterprise, and the safety reviews, the USS Unity was not ready until february 2016. This was the first plane to be built in house by The Spaceship Company.

WhiteKnightTwo carrying VSS Unity during the flight test, it will drop the craft at 50,000 ft. Credit: Virgin Galactic.

Up until this point the testing has been more gradual than planned, with captive carry tests, and a total of 6 successful glide tests. There was a dry run rocket test on 4th of August 2017, where water was mounted in place of rocket fuel to simulate the shift in gliding with various centres of gravity, as well as the change of weight as the rocket uses up the fuel. These tests ended positively, with the Chief pilot David Mackay stating “We are really pleased with what we saw today. We collected hundreds of gigabytes of data for us to review, and from the pilots’ point of view, it felt really wonderful.”

Pilots walking
The pilots walking toward the VSS Unity to conduct the first powered test flight. Credit: Virgin Galactic.

The FAA approved a revision to Virgin Galactic’s Commercial Space Transportation Licence in 2017. This allowed Virgin Galactic to launch out of Spaceport America in New Mexico as well as Mojave Air and Space Port in California. Virgin also announced that the Kingdom of Saudi Arabia would invest $1 billion across the Spaceship Company, Virgin Galactic and Virgin Orbit.Currently under review, if approved the deal would help finance SpaceShipTwo during 2018.

WhiteKnightTwo taking off
WhiteKnightTwo taking off to conduct the first powered test light of VSS Unity being held underneath it. Credit: Virgin Galactic.

VSS Unity is powered by a hybrid rocket engine called RocketMotorTwo. The engine originally used rubber based hydroxyl-terminated polybutadiene (HTPB) as the fuel, and nitrous oxide as the oxidiser. In 2014 Virgin Galactic switched to a plastic based thermoplastic polyamide for the fuel to improve performance. Although tested, and not the cause of the crash of VSS Enterprise, Virgin Galactic opted to use HTPB after extensive testing at Mojave.

spaceport America
VSS Unity attached to WhiteKnightTwo flying over Spaceport America. Credit: Virgin Galactic.

The test used WhiteKnightTwo to lift the VSS Unity to an height of 50,000 feet, then release it. Once clear, VSS Unity ignites and ascends rapidly. The burns during the real flights will last just over a minute, but this test used a much shorter burn. This is the incremental approach that Virgin Galactic have opted for. Unlike a normal rocket, the engine thrust will decrease over time, so that the G-forces stay reasonably comfortable, as this is meant to be a pleasure ride. Once the engine cuts off, the craft coasts to the apogee and glides back to the spaceport. The tests can only get the craft to 80 km, which is not officially recognised as space, due to the extra test equipment needed. Virgin Galactic claim to be confident that the craft will reach space in the final version.

What We Learnt From The Peter Beck AMA

Peter Beck is the CEO and founder of Rocket Lab, a US/New Zealand orbital launch provider who is trying to provide access to space for small satellites. On at 19:00 UTC on April 5th he participated in a Reddit AMA on /r/space, where he answered as many questions as he could about the Electron launch vehicle and the upcoming ‘it’s business time’ launch, as well as what the future of space access looks like. It was a good AMA, he answered lots of questions, and the full post can be found here. This post is to round up some of the most common and important questions he got asked for those interested.

Peter Beck by Electron
Peter Beck, president of Rocket Lab in front of the Electron launcher. Credit: Rocket Lab

The most questions came with reference to SpaceX, and the way their business model compares to Rocket Lab.

SpaceX didn’t see a market It’s known that the Falcon 1 was a similar size to the Electron and they quickly moved on from it. So people asked if SpaceX didn’t stay with it, why will it work for Rocket Lab?  Peter makes the point that SpaceX retired that rocket 10 years ago, and most of Rocket Labs customers didn’t even exist then. He mentioned that Electrons manifest is fully booked for the next 2 years for dedicated flights. He also doesn’t see a slowdown in demand anytime soon.

Reusability – On the SpaceX front, they have made big inroads to reusability and the Electron is not reusable, so many asked about plans to make a reusable version. The simple answer he gave was that reusability makes sense for medium lift vehicles like the falcon 9, but it doesn’t scale well to small vehicles. So it isn’t on the radar for them at the moment.

Electron Launch Vehicle
Rocket Lab’s first Electron rocket, seen here in a hangar at the company’s New Zealand launch site. Credit: Rocket Lab

Other Rocket Manufacturers – As there are many small rocket manufacturers popping up, and attempting to compete in this space, many wanted to know what the market is actually like for them. His comment was that not all of those manufacturers will make it, and they are currently the only dedicated small launcher that has actually made it to orbit. Others were quick to point out that other rockets of similar size do launch but nowhere near as frequently and do not have the same quality or launch frequency as the Electron.

Where else will they launch from – Currently they have a single launch site, but many wanted to know if they will branch out, to different pads of even different countries, maybe even pad-39A. He mentions that he wants to have many potential launch pads to serve many different inclinations, but Launch Complex 1 is a good start.

Going Bigger – There were lots of questions about making a bigger rocket, like an Electron Heavy. He made a point of saying they are currently only making one product really well. They have no plans to make bigger rockets, and they understand the market they are in. Rocket lab do not want to compete with SpaceX on these launches. He mentions that they can launch a huge amount of spacecraft to LEO, and going bigger only allows a 2% increase in market at the moment. That being said they will continue improving the rocket as they go along.

electron on the pad
The Electron launch vehicle waiting on the pad for takeoff, Credit: Rocket Lab

Using composites – As the LOX tank and other parts are made of carbon composites, there were questions about the difficulty surrounding the design and development of that. He talked about the several years developing and testing the composite tanks. The two main issues being microcracking and oxygen compatibility. They ended up with liner-less tanks with common bulkheads that have similar oxygen compatibility to aluminium but much lighter mass. All the composite manufacturing is in house. Some wanted to know how they manage to use such expensive processes, and he says that although carbon fibre is expensive, when done right you can use very little of it.

Why black – with most rockets out there being white, to help with the thermal efficiency, why did they go for black? Well the simple answer he gave was it looks better. Many engineers wanted to paint it, but the thermal experts made a special effort to make sure they could keep it black. Also, it does save some time/money/weight on paint.

It’s all about the money – The key question is, is it profitable, and when will they start making those profits? Well Peter states that they will see positive cash flow after their 5th flight. Each launch costs $4.9 million to each customer, and they get a dedicated launch, so no need to worry about rideshares where they have less control.

Electron Launch
Electron Rocket takes off from Rocket Lab Launch Complex 1 during the “Still Testing” mission. Credit: Rocket Lab

Adding to space junk – In the news recently, there has been lots of the junk that currently floats in space, so there were some questions on how the Electron tries to stop being just more rubbish. Peter talks about the Curie stage of the rocket that is designed to fix this issue. It puts it the second stage into an orbit that makes it deorbit quickly, and the kick stage can deorbit itself. Also most of the LEO payloads they will orbit will deorbit within 5-7 years.

Launch cadence – A few asked how often they are able to launch rockets, or at least the plans to do so. He mentioned that the current plan is to launch once a month for the next year, then once every two weeks, and then double down from there. The Launch complex 1 can support a launch every 72 hours, which is pretty impressive.

Job opportunities – As you would expect, many people asked how you get a job/internship at Rocket Lab. Peter gave a link to email a resume to, but mentioned that the bar is high, they are open to new people but they have to be passionate, and enjoy (and be good at) what they do. They are a small team trying to do big things! They care about what you do outside your formal education, what are you passionate about? what have you built, tested and broken?

Rocket testing
Rocket Lab testing its engines for the Electron launch vehicle. Credit: Rocket Lab

Some hardcore technical answers

  • Each propellant had a dedicated and independent pump system rather than a single electric motor.  That was due to wanting super accurate control over the oxygen fuel ratio and startup and shutdown transients.
  • Ignition is from an augmented spark igniter (a spark plug surrounded by a tube, what acts sort of like a blowtorch).
  • The engine is fully regeneratively cooled, 3D printed chamber.
  • The area ratios for the booster and vacuum nozzles are 14 and 100 respectively.
  • The steering and ullage on the upper stage is controlled by cold gas RCS and PMD.
  • The whole vehicle is non pyro, the decouplers are all pneumatic.

Arianespace Launches a Successful Soyuz

VS18 liftoff
VS18 taking off from the Soyuz Launch Complex (ELS) near Sinnamary.

At 17:10 UTC on the 9th of March 2018, Arianespace launched its second rocket of the year from Guiana Space Center at Kourou. Designated VS18, the Soyuz rocket launched four O3b Satellites into orbit more than 3 years after the last O3b launch. Controlled by a Russian ground crew from the Soyuz Launch Complex (ELS) near Sinnamary, there was a 33 minute delay to the start because of bad weather. The Soyuz used was a Soyuz 2-1b/Fregat placing the satellite in Medium Earth Orbit (MEO).

The VS18 launch from Instagram
The VS18 launch from the Instagram of Arianespace.

A somewhat complex launch, the first ascent lasted 9 minutes and 23 seconds placing the launcher in a sub orbital trajectory. After separation the Fregat performed a 4 minute burn to reach 160 x 205 km x 5.16 deg parking orbit. Coasting for 8 minutes, the Fregat performed its second burn for 8 minutes and 36 seconds to enter  a 190 x 7,869 km x 3.88 deg transfer orbit. Then after a coast of 1 hour and 21 minutes to the apogee, the Fregat fired for its third and final time for 5 minutes and 6 seconds, to enter its 7,830 km x 0.04 deg insertion orbit.

Poster of VS18 launch
Poster advertising the VS18 launch from the Arianespace website.

After the third burn, the satellites were release two at a time, with opposite satellites released at the same time. The first were released 2 hours into launch, and the second set 22 minutes later after a short firing of the Altitude Control System. The rocket then performed 2 more burns to lower its orbit to 200 km below the O3b release point. This was a disposable orbit, intended so that it will not interfere with working satellites.

The four 700kg satellites
The four 700kg satellites being lowered being loaded into the fairing, before the launch. Image from Arianespace website.
The O3b Satellites being prepared to be transported
One of the O3b Satellites being prepared to be transported to the launch site.

The Ka band satellites are the fourth set of O3b to be sent up, making the total constellation 16. Arianespace intend to launch the next set of four in 2019. “The new Ka-band satellites will join the existing O3b constellation to deliver high-speed connectivity to people and businesses in the growing mobility, fixed data and government markets,” Arianespace officials said in a statement. It was reported that the launch was a success, and the Luxembourg based satellite operator SES Networks now have control of the O3b’s.

The fairing of VS18 ready to launch
The fairing of VS18, ready to be attached to the Soyuz rocket, picture from Arianespace website.

The second launch of the year, Arianespace delayed the launch from the original March 6th launch date. This was postponed to conduct extra checks, likely inspired by the partial failure of the Ariane V earlier this year. On January 25th the company lost contact with the upper stage of the rocket. The 3 satellites on board did reach orbit despite the anomaly, but Arianespace have been quiet on the condition of them.

Launch of VS18 with four Ob3
Launch of VS18 with four Ob3 satellites on board. Image from Arianespace website.