The U.S. Defense Advanced Research Projects Agency has scrapped plans to launch small satellites from a modified F-15 fighter jet after two tests of a new rocket fuel ended in explosions this year.
Instead DARPA will spend the next year studying how to harness the volatile nitrous oxide-acetylene propellant and, in parallel, modifications to existing small rockets that would enable the agency place small satellites on orbit on 24 hours notice at a cost of less than $1 million.
In March 2014, Boeing Defense Space and Security of Huntington Beach, California, won a contract potentially worth $104 million to build and demonstrate the Airborne Launch Assist Space Access (ALASA) system. The program was intended to demonstrate the capability to launch up to 45 kilograms of payload into low Earth orbit on short notice for as little as $1 million.
ALASA is one of a number of DARPA efforts to reduce the cost and turnaround time for launching national security satellites.
Boeing’s design featured a small expendable rocket launching from underneath a modified combat aircraft that would take off from a standard airport runway. Such a system would allow the Defense Department to launch from almost anywhere, DARPA said.
“The magic” in Boeing’s design, as DARPA officials described it, was the powerful nitrous oxide-acetylene propellant, also known as NA-7. The propellant would be “pre-mixed” to reduce the plumbing needed on the rocket, enabling it to carry more payload.