How Do SRB Work?
The Solid Rocket Boosters (SRBs) operate in parallel with the main engines for the first two minutes of flight to provide the additional thrust needed for the Orbiter to escape the gravitational pull of the Earth.
Reasons you might have to repay your bonus can include, but are not limited to: voluntary separation, misconduct, failure to meet standards, failure to meet technical qualifications, cross-training into a new career field before completing the terms of your contract, and possible other reasons.
This is called the Selective Reenlistment Bonus (SRB) plan. The program provides a monetary incentive to sailors with critical skills and experience to stay Navy and rewards sailors who possess special training in skills that are most needed in the fleet.
Navy SRB Guidance, December 2019 The Navy's Selective Reenlistment Bonus is calculated by multiplying your basic pay (times) number of SRB eligible months reenlisting for (divided by 12) then multiplied by the SRB award level for your zone.