Q: Why rocket engines instead of ramjets or scramjets?

We use rocket engines because they cost less to develop and build. It costs hundreds of millions of dollars to develop supersonic jet engines because they are heavy and complex.That said, rockets do use fuel faster than air-breathers - and practically-sized rockets flying ballistic trajectories have very short ranges. Long-range ballistic trajectories require huge, Starship-sized, rockets. But, we’ve solved that problem by using a “boost-cruise-glide” approach, based on decades of work by the military. Boost-cruise-glide extends our range to make our fuel efficiency competitive with air-breathing aircraft.

Q: What about the sonic boom?

In level flight, the Rocketliner® is so high that the boom barely reaches the ground. Our sonic boom calculator (based on NASA and FAA work) shows a perceived loudness of 51.6 dB on the ground. What about the sonic boom when the aircraft lands?Unlike our competitors, our boom will be momentary and concentrated in one place - the area below the descent, about 193 km away from the landing pad.We will plan our flight path so that this small area is overwater or in sparsely populated areas.That’s quieter than a normal conversation and much quieter than a small jet departing from a runway 6.5 km away.

Q: Why are you using Liquefied Natural Gas (LNG) instead of Hydrogen or kerosene-based rocket propellant?

LNG is denser than Liquid Hydrogen, so it reduces the size and mass of the aircraft structure. And it burns up to 80% cleaner than kerosene (using our trajectory).According to the California Air Resources Board when produced from agricultural, wastewater, landfill and other renewable sources, Bio-LNG has a lower Carbon Intensity than Synthetic Aviation Fuel, Hydrogen or even electricity.

Question 1

Why Vertical take-off and landing (VTOL)?

Accepted Answer

There are over 6,000 improved heliports in the US. There are over 4,000 paved runways longer than 1,000 meters. We can take off and land from these ~10,000 airports and heliports.On the other hand, there are less than 2,000 paved runways over 1,500 meters. Runway-dependent supersonic and hypersonic aircraft are limited to these <2,000 runways.The Defense Department is also interested in breaking its dependence on runways.

Question 2

Why rocket engines instead of ramjets or scramjets?

Accepted Answer

We use rocket engines because they cost less to develop and build. It costs hundreds of millions of dollars to develop supersonic jet engines because they are heavy and complex.That said, rockets do use fuel faster than air-breathers - and practically-sized rockets flying ballistic trajectories have very short ranges.  Long-range ballistic trajectories require huge, Starship-sized, rockets. But, we’ve solved that problem by using a “boost-cruise-glide” approach, based on decades of work by the military.  Boost-cruise-glide extends our range to make our fuel efficiency competitive with air-breathing aircraft.

Question 3

What about the sonic boom?

Accepted Answer

In level flight, the Rocketliner® is so high that the boom barely reaches the ground.  Our sonic boom calculator (based on NASA and FAA work) shows a perceived loudness of 51.6 dB on the ground. What about the sonic boom when the aircraft lands?Unlike our competitors, our boom will be momentary and concentrated in one place - the area below the descent, about 193 km away from the landing pad.We will plan our flight path so that this small area is overwater or in sparsely populated areas.That’s quieter than a normal conversation and much quieter than a small jet departing from a runway 6.5 km away.

Question 4

Why are you using Liquefied Natural Gas (LNG) instead of Hydrogen or kerosene-based rocket propellant?

Accepted Answer

LNG is denser than Liquid Hydrogen, so it reduces the size and mass of the aircraft structure.  And it burns up to 80% cleaner than kerosene (using our trajectory).According to the California Air Resources Board when produced from agricultural, wastewater, landfill and other renewable sources, Bio-LNG has a lower Carbon Intensity than Synthetic Aviation Fuel, Hydrogen or even electricity.