SpaceX Set for Sunday Sea Satellite Launch, Booster Recovery Attempt
SpaceX has leased an area to build a west coast landing zone, but it wasn’t clear what drove the final decision to use the drone ship. The vessels are used when a return to land is not feasible, including when the Falcon’s first stage must reach a higher velocity before separation. Assuming a combined upper stage and payload mass of 125 metric tons, Musk said a velocity of 5,000 kilometers per hour was slow enough to return the booster to land, while 8,000 kilometers per hour necessitated use of a drone ship.
The Jason-3 satellite weighs 510 kilograms, while each of the 11 ORBCOMM satellites launched in December weighed 170 kilograms, for a total payload mass of about 1.8 metric tons. But Jason-3 is headed to a 1380 by 2328-kilometer orbit, much higher than the ORCOMM payload’s 750 by 615-kilometer trajectory. Additionally, west coast launches—which are used to send spacecraft to high-inclination orbits—lose the speed advantage provided by the direction of the Earth’s rotation. The Jason-3 Falcon booster is also not equipped with the high-thrust upgrades introduced during the December ORBCOMM mission.
Sourced through Scoop.it from: www.planetary.org