This article originally appeared in the May 6, 2019 issue of SpaceNews magazine.

Some people see the proliferation of startups developing rocket engines as a sign of the space industry’s vibrancy. Jeff Greason calls it “f—ing insane.”

“It’s a sign of the immaturity of the industry,” Greason, former XCOR Aerospace co-founder and chief executive, said at the Space Access 2019 conference in Fremont, California, last month.

In every other transportation industry, vehicles adopt common engines because engine development is labor-intensive, time-consuming and requires a lot of specialized expertise, said Greason, who leads Agile Aero, a company focused on rapid prototyping for aerospace vehicles. “If you don’t divide that among many units of production, you’re not competitive.”

Despite that warning, launch vehicle startups remain focused on unique engine designs. At last count, there were 129 rocket startups, Rich Pournelle, NanoRacks senior vice president for business development, said at the April conference.

How many will survive? Eric Salwan, Firefly Aerospace commercial business development director, suggested the market could support three, four or five.

Because it’s sometimes difficult to gauge the progress of the small launch vehicle startups, Pournelle shared his own criteria. Has the company fired its rocket engine in flight configuration for the full duration required? And if so, how often do they fly? Those questions set the agenda for much of the discussion that followed.

Of the presenters, only Rocket Lab had completed the full-duration burn. As of April 18, the Huntington Beach, California, company had sent 25 satellites into orbit on four launches of its Electron rocket from the company’s private launch site in New Zealand.

Rocket Lab plans to complete construction of a second launch site on Wallops Island, Virginia, by the end of the year, said Grant Bonin, Rocket Lab chief payload systems engineer. The firm’s “entire emphasis is on flight cadence,” Bonin said. Once the Wallops site is operating, Rocket Lab plans to conduct launches every two weeks. “Our eventual goal is to get to a launch cadence of about 72 hours,” he added.

Firefly Aerospace of Austin, Texas, is preparing to conduct a full duration burn of its Alpha launch vehicle second stage engine, Salwan said. After that, Firefly will begin first-stage engine testing.

The company is “pushing very hard for our first launch in December,” Salwan said. “It will be hard. It’s an aggressive schedule.”

Firefly plans to begin manufacturing rockets in Texas while constructing a factory in Florida to produce as many as 24 Alphas per year. Liquid oxygen and kerosene-fueled Alpha rockets will sell for $15 million and place 1,000 kilograms into low Earth orbit, Salwan said.

Relativity Space, the Los Angeles company seeking to additively manufacture Terran 1 launch vehicles, has conducted more than 124 tests of its liquid methane and liquid oxygen-fueled Aeon 1 engine at NASA Stennis Space Center.

“We have yet to do a full-duration test, but that has not been limited by the engine,” said Sam Tonneslan, Relativity lead materials engineer. “That has been limited by the test site facilities.”

Relativity’s goal is to 3D print engines in 60 days and charge $10 million to send 1,250 kilograms to low Earth orbit from Cape Canaveral Air Force Station in Florida, Tonneslan said.

Exos Aerospace of Greenville, Texas, announced plans to develop an orbital rocket based on its reusable Suborbital Autonomous Rocket with Guidance (SARGE) powered by liquid oxygen and ethanol. In 2018, Exos executives traveled to Italy to forge an agreement to offer suborbital launches from the Basilicata Region.

“We went out there to do suborbital and we came back saying, ‘This is where we want to do our orbital program,’” said John Quinn Exos co-founder and chief operating officer. “Their regulations and economics make that all work very well and fit right into our business plan.”

Exos will derive technology concepts and flight code for its orbital Jaguar rocket from SARGE, which has flown twice, Quinn said.

Jaguar vehicle specifications remain to be determined but the launch vehicle is likely to accommodate 150- to 300-kilogram payloads and begin launching in 2022, Quinn said.

Vector Launch of Tucson, Arizona, is developing two liquid oxygen and propylene fueled rockets: Vector-R to send 50 kilograms to low Earth orbit at a cost of $1.5 million and Vector-H to launch 250-kilogram payloads for $4.5 million.

“Before you ask, we have not done a full-duration 100 percent burn yet with either our first or second stage engine,” said Gregory Orndorff, Vector government sales vice president.

Vector has conducted suborbital Vector-R launches from California’s Mojave Air and Space Port and Spaceport Camden in Georgia. Vector-R is designed to fly from a mobile launch platform with the support of only “a handful of employees,” Orndorff said.

Vector is preparing to conduct a series of stage fire tests in Tucson with its first all composite launch vehicle, Orndorff said. “After that, we’re going to take that vehicle and do a suborbital test this summer,” he added.

While many Space Access speakers described their race to market, Launcher of Brooklyn, New York, is taking its time.

“We don’t believe being first to market will be the winning move,” said Max Haot, Launcher founder and chief executive. “We believe that performance, which leads to more payload and higher margins, will be the long-term winning move in the industry.”

Launcher is focused on building E-1, a kerosene and liquid oxygen-fueled engine. “We hope it will be the highest performance, lowest cost engine in its class,” Haot said.

After that, the company will develop the rest of Rocket-1, a vehicle to loft 773 kilograms to 200-kilometer orbit with test flights starting in 2024, Haot said.