The Rocketship charter school network has abandoned plans to open a third campus in D.C. at the start of the new school year, slowing the chain’s ambitious expansion goals in the District.

The California-based network said not as many students enrolled as expected — only 22 had signed up — and it had struggled to find an affordable building for its proposed elementary campus in Northeast Washington. The last-minute decision left students scrambling to find a school.

“The cost became too prohibitive,” said Jacque Patterson, D.C. regional director of Rocketship Education. “It would have taken away from the teachers we could hire and the programming we could do — and that would have not been fair to the students or parents.”

Rocketship opened its first charter school in 2007 in California and initially burnished a national reputation for impressive test scores among low-income, minority students and for a blended-learning approach — mixing traditional teaching with online and computer-assisted instruction. That approach keeps administrative costs low, but the school’s heavy reliance on technology has been controversial. Rocketship also has struggled to sustain test scores as it expands.

The D.C. Public Charter School Board voted in 2013 to allow Rocketship to open as many as eight schools in the District, as long as its campuses reach academic thresholds. Rocketship opened its first D.C. elementary school in Southeast in 2016, and it opened a second campus two miles away in 2017. Rocketship’s inaugural school in D.C. has a waiting list to attend.

Charter schools are publicly funded but privately operated.

Patterson said the third school was supposed to open in an unused part of a campus that Perry Street Prep and Latin American Montessori Bilingual share in the Brookland neighborhood of Northeast Washington. Latin American Montessori was expected to move next academic year, making room for Rocketship, but the Montessori school’s plans changed.

Thus, Rocketship planned to move to the third floor of the building, but renovations were running $250,000 over budget, Patterson said. The site was supposed to be temporary until Rocketship found a larger permanent home.

Patterson said the construction costs, on top of low enrollment, made the third campus unfeasible. Rocketship’s third campus could have accommodated 160 students in the temporary space and had 22 confirmed enrollees as of April 30.

Five of the 22 students were enrolling in pre-K3, and Patterson said those children have secured slots in a branch of the AppleTree Institute preschool inside the Perry Street Prep building. Seven of the 22 students are enrolled in a Rocketship school in Southeast Washington but wanted to transfer to the Northeast campus to be closer to home.

Patterson said Rocketship has worked with the remaining students to find slots in other schools. Families wishing to enroll in a charter school or traditional public school must apply through a competitive lottery, which had a March 1 application deadline for preschool and elementary students. The enrollment deadline was May 1.

Another 22 students matched to the school through the lottery but had not enrolled as of April 30.

Patterson said the Rocketship network hopes to open a school in Northeast Washington’s Ward 5 in 2019.

“I feel really bad that our school is not opening,” Patterson said. “We really would like to keep our promise to Ward 5 parents who put their faith in us.”