As We Wait for Starship Flight Test 3...

Within the last 24 hours over at Starbase Boca Chica, Booster 10 was rolled from the high bay assembly area to a test pad in the Sanchez site where engines can be added - as I understand it.  The common rumor is that Booster 10 and Ship 28 will be the next combination to fly.  

An article on Ars Technica today gives the impression that NASA is adding to pressure to fly tests more often with the specific goal of seeing some trials for on-orbit refueling.  

NASA is keen on demonstrating orbital refueling technology, an advancement that could lead to propellant depots in space to feed rockets heading to distant destinations beyond Earth orbit. In 2020, NASA announced agreements with four companies—Lockheed Martin, United Launch Alliance, SpaceX, and a Florida-based startup named Eta Space—to prove capabilities in the area of refueling and propellant depots using cryogenic propellants.

While they mention the October 2020 contract, they don't mention that SpaceX was first picked to work on orbital refueling over a year earlier, August 2019.   NASA announced that SpaceX and two NASA centers, the Glenn Research Center in Ohio and the Marshall Space Flight Center in Alabama, would work together on space-borne refueling systems.  

This is far from a new concept it's just that nothing has been done about developing methods to do it and fly them to verify they work.  Bobby Braun, a former chief technologist at NASA who is now dean of the College of Engineering and Applied Sciences at the University of Colorado Boulder has said, "I’ve got a stack of studies that go from the floor to the ceiling that list the critical technologies needed for humans to become long-term explorers in deep space, and in-space refueling is always on the list." 

Among the problems that need to be solved, the one that stands out most is dealing with cryogenic fluids, which must be held hundreds of degrees below zero.  Russian supply freighters regularly refuel the International Space Station with hydrazine and nitrogen tetroxide, which are room-temperature rocket propellants that can be stored for years in orbit, but the more efficient cryogenic propellants have typically been used on missions measured in hours.  There's a handful of technologies needed to address the problem, such as powering coolers that work on orbit, insulating the tanks properly and more.  Simply getting it to flow where it's supposed to go without gravity is an issue.

NASA and several companies are funding efforts in this area, called cryogenic fluid management. NASA's agreements from 2020 committed more than $250 million in government funding for cryogenic fluid management tests in space. These funding agreements announced in October 2020, called "Tipping Point" awards, require substantial private funding from the companies participating in the demonstrations.

As we passed the three year anniversary of that October 2020 contract award, only SpaceX appears to have a chance to complete the tasks outlined in its $53 million "Tipping Point" award.  

This test would involve transferring super-cold propellant from one tank to another inside a Starship spacecraft. It's a precursor to future, more complex demonstrations involving two giant Starships docked together in Earth orbit. Then SpaceX will be ready to send a Starship toward the Moon for a test landing without astronauts onboard. Once that is successful, NASA will clear Starship for a crew landing on the agency's Artemis III mission, marking the astronauts' return to the lunar surface for the first time since 1972.

That's easier said than done and as the saying goes, the longest, hardest journey begins with a single step. That first step could come on the next Integrated Flight Test of B10/S28. 

Lakiesha Hawkins, deputy associate administrator for NASA's Moon to Mars program office, discussed the Artemis schedule Monday with a committee from the National Academies charged with reviewing the agency's workforce, infrastructure, and technology programs.

Hawkins did not verbally address SpaceX's plans for the next Starship test flight, but one of her slides noted SpaceX is "moving quickly" toward the third Super Heavy/Starship launch and that this flight "will include a propellant transfer demonstration."

A preliminary test, according to Jimi Russell, a NASA spokesperson, will be for the Starship to transfer about 10 metric tons of liquid oxygen between tanks on the Starship.  Moving 10 metric tons of cryogenics between tanks while on orbit has never been done before. 

The ship attached to the crane is Ship 28 - possibly the next Starship set to fly.

There's no guarantee that this means the next flight will carry out this test, but the fact it's being talked about is noteworthy.  It's a major milestone in the development of Starship, in the Artemis lunar missions and absolutely essential to getting people to Mars.  It's that "one first step" starting the long journey.  Starships are capable of holding 1200 metric tons of fuel and oxygen. After sloshing 10 metric tons around one Starship, they'll need to transfer fuel to a different Starship and increase quantities.   

Back after Flight Test 2, Elon Musk tweeted that 3 could be by the end of December.  Of course that's Elon Standard Time and says nothing about FAA delays.  After derating for those two factors it pushes out.  This site says NET February, and that's probably a reasonable guess.