PHOENIX — Two entrepreneurial space companies best known for their work on suborbital reusable launch vehicles say they are in the early stages of development of orbital launch systems.

In a presentation at the Space Access ’15 conference here May 2, XCOR Chief Technology Officer Jeff Greason said he is starting to spend more time on the design of an orbital vehicle as development of the company’s Lynx suborbital spaceplane begins to wind down.

XCOR Jeff Greason
XCOR Chief Technology Officer and Chairman Jeff Greason. Credit: SpaceNews/Tom Kimmell

“The orbiter is personally what I am spending a little more of my time on,” he said, adding that he moved from the role of president and chief executive to chief technology officer earlier this year so he could spend more time on engineering. “More and more of the time I have available to think on technical stuff goes into the orbiter.”

XCOR’s orbiter concept, he said, involves a two-stage vehicle air-launched from an existing aircraft. Both stages would be reusable, with the first stage returning to the launch site immediately after separating from the upper stage. That upper stage, Greason said, “goes around the Earth as many times as necessary” before returning to the launch site.

The vehicle would be able to place as much as 500 kilograms of cargo, or two people, into orbit. Greason said the “target operational tempo” for the orbital vehicle is one flight every other day.

Greason offered no schedule for the development of the orbital system, but said the company would work on it at its new headquarters in Midland, Texas. The company is in the process of moving there from its facilities in Mojave, California.

He said about 20 employees would stay behind in Mojave to complete work on the prototype Lynx Mark 1 and see it through first flight while the rest of the company moves to Midland. The company expects flight tests to start no sooner than late this year, after the wings are completed.

Another Mojave-based suborbital vehicle company, Masten Space Systems, is also working on orbital vehicle concepts. In a conference talk May 2, Masten Chief Technology Officer Dave Masten unveiled a reusable orbital vehicle concept called Xephyr, based on work the company is doing on the Experimental Spaceplane 1 (XS-1) program for the U.S. Defense Advanced Research Projects Agency.

“Xephyr is the commercial vehicle that would be built after the XS-1 program is done,” Masten said. Xephyr would carry a second stage for placing satellites into orbit, the design of which, he said, “is a little bit in flux right now.”

Masten Space Systems was one of three companies that received XS-1 study contracts from DARPA last year. Masten said he could not discuss the company’s ongoing work on XS-1 since he did not receive clearance from DARPA in time for the conference.

Xaero rocket. Credit: Masten Aerospace

The XS-1 program is designed to develop a reusable first stage to support frequent launches of payloads weighing up to 2,200 kilograms. Masten said Xephyr would have similar capabilities, and that he sees the best market in the launch of small and medium-sized satellites to sun-synchronous orbits.

The company’s work on XS-1 and Xephyr is going on in parallel to its suborbital vehicle efforts. Masten said the company has started tests of two new vehicles. One, called Xaero-B, will eventually fly to high altitudes and speeds. A second, whose name he did not disclose, would be used for low-altitude technology demonstration flights, replacing the company’s existing Xombie vehicle.

Those suborbital and orbital projects will require the company to raise additional funding. “For the last three-plus years, we have been running entirely off customer revenue,” Masten said. “We are at that point where we have to do some serious growth, so we’re going to be looking for some investment dollars.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...