Ex-SpaceX engine expert to help design rockets built for launch on world’s largest jet

[Elderberry]

Teslarati By Eric Ralph 8/22/2018

Stratolaunch, an aerospace company funded by Microsoft-made billionaire Paul Allen to build the world’s largest flightworthy aircraft, has announced a decision to build its own liquid-fueled rockets, to be air-launched from the aforementioned mega-plane.

Targeting an inaugural launch of the first version of the rocket – currently nicknamed “Kraken” – as early as 2022, Stratolaunch has chosen Jeff Thornburg, formerly SpaceX’s Vice President of Propulsion Engineering and the father of the company’s Mars-focused Raptor engine, to lead its foray into in-house rocket propulsion development and manufacturing.

But first: building the world’s largest aircraft

Stratolaunch’s first task at hand, however, is to begin flight-testing the largest (hopefully) operational aircraft in history, a prerequisite for the company’s longer-term orbital rocket and spaceplane aspirations. Nicknamed “Roc” after a mythical (and fictional) bird so large it could carry an elephant, the plane certainly lives up to its namesake. Featuring a full six of the same engines that power Boeing’s once-record-breaking 747 airliner and a wingspan that could easily fit three smaller 737 airliners with room to spare, it is genuinely difficult (if not impossible) to successfully convey the sheer scale of Roc outside of witnessing it in person.

Stationed in California’s Mojave Desert, the aircraft’s one and only copy is, for the most part, completed and has spent the brunt of 2018 conducting runway taxi tests, hopefully culminating in an inaugural flight test later this year or early next year. Designed to lift orbital-class rockets weighing as much as 250 metric tons (550,000 lb) to an altitude of at least 9100 meters (30,000 feet), the primary benefit of using aircraft as launch platforms derives from the simple fact that the atmospheric density at 30,000 feet is more than three times less than that at sea level. Similar to aircraft, rocket performance dramatically improves as atmospheric density decreases: less atmosphere means lower drag and pressure.

More: https://www.teslarati.com/ex-spacex-engineer-air-launched-rockets-largest-aircraft/

[thackney]

...Stratolaunch's appeal lies in the fact that it can use smaller, cheaper rockets to reach orbit. The rockets to fly on Stratolaunch require fewer stages, meaning it's less likely something will go wrong—and with rockets, wrong is generally catastrophically wrong. As an airplane, Stratolaunch can also fly around the bad weather that might ground a rocket taking off from a stationary pad....



https://www.popularmechanics.com/military/aviation/a22802701/does-stratolaunch-have-a-top-secret-purpose/

...This has led to some speculation that Stratolaunch is in fact a Department of Defense project hiding in plain sight. Quartz compares the airplane to the Glomar Explorer, a deep sea drilling ship ostensibly designed to harvest manganese ore from the ocean floor. In reality, the Glomar Explorer was meant to salvage a sunken Soviet nuclear-armed submarine on the bottom of the Pacific Ocean. The ship was so large and unusual that it was impossible to construct in secret, so it was simply built with a cover story....