Capella Space is preparing for its first launch on a SpaceX rocket this fall, an important milestone in the company’s plan to build a constellation of the world’s smallest commercial radar satellites.

Capella satellites will weigh less than 40 kilograms, which means four will fit on a single Rocket Lab Electron rocket, said Payam Banazadeh, Capella co-founder and chief executive.

By launching four satellites on each rocket and sending rocket into different planes, Capella will “build a constellation of many planes and orbits with the least amount of operational and deployment complexity,” Banazadeh said. “It allows us to deploy our constellation efficiently in a shorter time frame and with less capital” than constellations of larger satellites.

Several companies around the world are developing constellations of small satellites equipped with Synthetic Aperture Radar (SAR), which unlike optical cameras can gather imagery in all weather conditions day and night. U.S. military and intelligence agencies are eager for access to the persistent global observations that commercial radar satellite constellations can provide. In the long run, though, industry analysts expect the commercial market to eclipse government demand if small satellite constellations begin offering reliable and inexpensive radar data.

In orbit, Capella plans to unfurl antennas made of a flexible material the company declined to specify. Once deployed, the antennas will span eight square meters, Banazadeh said during a recent tour of the firm’s San Francisco headquarters.

Capella will not sell imagery from its first satellite but will use the data it gathers “purely for internal testing,” Banazadeh said. However, the firm is signing up customers for demonstrations and pilot experiments for its second satellite, slated to launch on an Indian Polar Satellite Launch Vehicle in early 2019, Banazadeh said.

In March, the National Oceanic and Atmospheric Administration awarded Capella a license to send two X-band SAR satellites into polar orbits between 450 to 600 kilometers with a 97.5 degree inclination.

Later in 2019, Capella plans to launch six additional satellites into two orbital planes. With those spacecraft, Capella will offer customers the ability to monitor any location in the world with a maximum revisit rate of six hours, Banazadeh said. Customers have signed “tens of millions” of dollars in contracts for data from those satellites, he added.

“Customers need persistent imagery to see how patterns are changing,” Banazadeh said. “We have found customers care about consistency. If you could do an average revisit of three hours but you have huge gaps in your coverage that is not as good as if you could make consistent measurements.”

With its first-generation satellites, Capella plans to offer imagery with a resolution of one meter or better, which Banazadeh said is “sufficient for 80 percent of current SAR applications.” Capella’s second-generation satellites, which will be slightly larger, will offer imagery with resolution better than one-half meter, he added.

Capella has about 40 employees in San Francisco and Boulder, Colorado, and is expanding quickly “because the contracts are all for [the] operational constellation we plan to have in place in 2019,” Banazadeh said.

Since it was founded in 2016, Capella has raised more than $15 million in private investment, including $12 million raised in 2017 through its Series A investment round led by Nabeel Hyatt of Spark Capital. Capella is currently raising Series B funding.

The Defense Innovation Unit Experimental, or DIUX, awarded Capella an additional $10 million in 2017 before issuing a stop-work order in October due to a lack of funding. That stop-work order has been lifted and Capella has resumed its DIUX work, Banazadeh said July 24 by email.

Hyatt said by email he’s backing Capella because it is “the only company with the capability to bring the cost of SAR down by 10x while still keeping the quality images the industry expects. In our experience when that happens, it not only transforms the current market, it often creates new markets no one has seen before.”