Rocketing toward first flight: Gary Lantz of Rocketplane Limited, Inc

OotC: Could you elaborate a bit more on the reaction of the folks at NASA, and the things that NASA is doing to help Rocketplane?

Although there are some controllability issues, suborbital re-entry is not the flaming ball of fire that most of the public envision. That’s only the case when coming in from orbital velocities.

Lantz: The NASA folks themselves have been very supportive of our program. I’m not sure where to begin, but we’ve had Space Act Agreements (SAA) with NASA Glenn to get training on trajectory simulation, we worked with NASA Marshall Space Flight Center through an SAA to do high speed wind tunnel testing, we are currently defining another SAA with NASA MSFC for a whole series of tests including Electrical power testing, RF antennae analysis, cryogenic tank design and a balanced flow meter design. Finally, the Johnson Space Center is loaning us the RS-88 rocket engine for use on our XP vehicle.

At the 44th Annual AIAA Aerospace Sciences Meeting in Reno, NV this last month, a representative from NASA Langley approached us to offer their services. What we’re finding is that they are just like the alt.space community; they are in the same industry and have the same passions as the rest of us. There is a lot of bureaucracy and red tape that has to be dealt with to work with a government facility, but in general the folks at NASA have helped us navigate through the paperwork.

OotC: Tell us a bit about the basic design of the Rocketplane XP vehicle, and where your discipline fits in.

Lantz: The simplest answer is it’s a horizontal takeoff/landing, fighter sized delta wing aircraft with two turbojet engines and a single rocket. We presented a paper on the conceptual design process at the annual AIAA convention in Reno, NV earlier this month. This paper will have the basic configuration, 3-views, dimensions, etc. I believe you can download a copy from our company website.

My role in aerodynamics is for the overall configuration, performance, stability and control of the vehicle. As a Systems Engineer, I assist with company policies and procedures and the cross discipline integration, interfaces, and overall vehicle optimization.

OotC: Are you building all the elements of Rocketplane XP in house, or do you have other companies providing components and sub-assemblies?

Lantz: We are primarily building the structure and hardware interfaces in house. Most of our other components will be supplied or built by some major industry players. Honestly, there are quite a few, probably too many to mention here. There is a list of systems in the technology section at www.rocketplane.com (under System Definitions) that highlights the companies currently under contract that support us; there are still others whose proposals we are evaluating.

OotC: What are the challenges involved in designing a vehicle that not only has to fly conventional runway takeoffs and landings, but also has to fly right out of the atmosphere and then re-enter?

We’ve developed a great relationship with the FAA and worked closely with them on defining the regulatory requirements. We’re still reviewing the officially released guidelines; we’re pleased so far.

Lantz: I believe our biggest challenge in the design is developing a wing that can handle the aerodynamic requirements while like an aircraft without interfering the rocket portion of the flight. Generally, we use the wings as much as possible for our trajectory profile, however when the vehicle goes nearly vertical, the wings themselves act more like fins. Because of this, we didn’t want a complex structure that would impart any unnecessary forces during ascent. We used a lot of the common tools available for subsonic and high alpha supersonic flight. It was a challenge to develop an aerodynamic database that we had confidence in, but after wind tunnel testing at Wichita State University and NASA Marshall Space Flight Center our confidence has grown significantly. We learned a lot about our tools from the wind tunnel testing.

It’s worth making a comment here about people’s tendency to believe that leaving the atmosphere is a huge feat. Although there are some controllability issues, suborbital re-entry is not the flaming ball of fire that most of the public envision. That’s only the case when coming in from orbital velocities. To put it in perspective, we’re only going 62 miles up. In a car, that’s less than a one-hour drive. A lot of people commute longer than that for work! To go to the International Space Station, you’re talking 250+ miles, or 4+ hours, of driving straight up; that doesn’t even factor in the difference in delta-v requirement, ours being closer to 1,500 fps while something like the shuttle is around 25,000 fps! Since energy is the square of the velocity, one can quickly see the significant difference. It’s somewhat counter-intuitive, but the trajectory profile that most of the commercial space tourism companies are shooting for is a lot closer to a high-speed military aircraft’s than the shuttle’s profile.

If someone sits down long enough, they’ll realize that the horizontal takeoff sub-orbital vehicle design hasn’t been on too many drawing boards. Most people are shooting for satellite launchers that require a lot more energy than our trajectory, or they are looking for orbital vehicles, again, a lot more energy. The X-15 was proving out high altitude technology, not developing a production vehicle, so it was not necessary to pursue a horizontal takeoff. My opinion is that the misperception of sub-orbit to orbit has caused a lot of people to assume the difficulties of a horizontal takeoff vehicle. As an engineer, when I first came on board with Rocketplane, I was surprised at the number of preconceived notions I had that were false. The same issues any high-speed aircraft has to work through are the ones we’re working through.

OotC: I understand that Rocketplane already has a professional test pilot on board in the person of former NASA astronaut John Herrington. He would bring some pretty unique knowledge and operational experience to the company. Are there aspects of the XP design that John has input into?

Lantz: His input has been very valuable for controllability and operations. He is heavily involved in the development and mitigation of any abort scenarios, panel layout, and in helping us tweak our trajectory profile to reduce the number of contingencies.

OotC: What do you see as being the trickiest part of designing and building a suborbital spaceplane?

Lantz: Technically speaking, there have been some issues getting vendors to talk to Rocketplane and take us seriously. Essentially everything we do is a “one off” without the luxury of government money and liability protection. One can just imagine the difficulties that arise.

We’ve had some issues with the lack of clearly defined regulations. For the last couple of years, there hasn’t been anything formal from the FAA about regulations or guidelines, just drafts. A lot of our preliminary work has been done based on our gut feelings as to what the FAA will mandate on us between conceptual design and production. I think it’s worked out in Rocketplane’s favour, however, since most of us are used to FAA Part 23/25 and MIL-SPEC regulations. The safety of the crew and participants is in our best interest, and so we’ve mandated some very stringent safety and reliability criteria internally.

Yes, metal is being bent!

As a result of this regulatory void, we’ve developed a great relationship with the FAA and worked closely with them on defining the regulatory requirements. We’re still reviewing the officially released guidelines; we’re pleased so far.

Finally, a surprising difficulty has been the hiring momentum. It seemed a lot of the needed skills were not located in the Midwest, and some people just didn’t want to move to Oklahoma. But we’re hiring fairly quickly now; I think we had 5 more people start in the last week.

Over the page – bending metal, schedules, and finances.

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