Mahalo for supporting Honolulu Star-Advertiser. Enjoy this free story! At the end of the first orbital test flight for its 164-foot Starship, SpaceX envisions a reentry into the atmosphere at speeds approaching Mach 25, or 19,000 miles per hour, followed by 15 minutes of hypersonic flight. During this time, the spacecraft will hurtle sideways, generating tremendous heat before adjusting to an upright position for a \u201csoft\u201d rocket-powered ocean landing 62 miles north of Kauai. It will sink in the Navy\u2019s Pacific Missile Range Facility, according to plans for the historic flight, and join dozens of warships that have gone down over past decades during Navy \u201csink exercises\u201d in waters 15,000 feet deep. Most recently that included the retired frigate USS Ingraham, which was targeted in mid-August by Marines firing Naval Strike Missiles from Kauai and pummeled by munitions from aircraft and a submarine. Hawaii\u2019s role in the orbital test of the biggest rocket ship ever built \u2014 394 feet with the \u201cSuper Heavy\u201d booster and Starship upper stage combined \u2014 has largely been revealed through regulatory filings. Eventually, Starship is expected to carry crews to Earth orbit, the moon and Mars. NASA, for its part, wants to fly a WB-57 high- altitude research jet close enough to the 30-foot-wide Starship\u2019s hypersonic reentry to gauge the surface temperature of the \u201cStarbrick\u201d thermal tiles that will take the brunt of the heat. Controllable fins will keep Starship in the right position. Current state-of-the-art thermal protection systems, or TPS, including ablators, ceramic tiles and reinforced carbon fiber \u201ctypically require significant maintenance between flights,\u201d meaning inspection, replacement time and cost, an Aug. 24 NASA report stated. \u201cStarship TPS is intended to provide a dramatic leap forward by demonstrating operational reuse requiring minimal to no maintenance between flights,\u201d NASA said. The space agency also offers a possible window for the Starship launch, saying it is \u201ctargeting (a) Starship reentry observation opportunity near March 2022.\u201d The timing is perhaps a more realistic estimation compared to a series of overly optimistic predictions by SpaceX founder Elon Musk, who tweeted on Oct. 22: \u201cIf all goes well, Starship will be ready for its first orbital launch next month, pending regulatory approval.\u201d Musk needs approval from the Federal Aviation Administration, and an environmental assessment is ongoing. The first orbital mission would include the stacked rocket launching from the SpaceX Boca Chica \u201cStarbase\u201d in Cameron County, Texas, with the Super Heavy booster first stage landing in the Gulf of Mexico and Starship second stage splashing down off Kauai after traveling nearly around the Earth in orbit. Super Heavy is expected to be equipped with up to 37 \u201cRaptor\u201d engines powered by liquid oxygen and liquid methane, according to the draft programmatic environmental assessment released in September. Starship will employ up to six Raptor engines. The flight is expected to take 90 minutes. As Starship enters its landing approach, likened to a speed-reducing belly flop, a sonic boom will be created. \u201cIt is SpaceX\u2019s intent to recover and reuse Starship and Super Heavy boosters,\u201d a June FAA biological assessment states. But the space company may require \u201cexpending\u201d either in the ocean \u201cduring early launches as the program develops.\u201d Its first proposed mission includes \u201cthe Starship second stage landing off the coast of Hawaii in the Pacific Ocean,\u201d the FAA said in an Oct. 18 document. \u201cSpaceX expects Super Heavy and Starship would break up on impact\u201d and sink because the spacecraft are mostly made from steel, a separate FAA report said. Musk\u2019s space flight operation has not identified all potential options for future landing sites and \u201cmay plan to land the Starship on islands in the Pacific Ocean,\u201d which would be analyzed in future reports if plans develop, according to the environmental assessment. Ted Ralston, a retired aerospace engineer, said Hawaii would likely be ruled out for a land-based return. Rather, SpaceX may have in mind sparsely populated or uninhabited islands in the Western Pacific with little commercial air traffic, he said. Eventually, SpaceX wants to launch and land its Super Heavy boosters and Star\u00adships back at Boca Chica \u2014 and it is adding steel arms at its 450-foot \u201cMechazilla\u201d launch tower to \u201ccatch\u201d the returning vehicles. \u201cGetting the permits to do the landings in Texas of the type that they are thinking of doing, which is a ballistic reentry, might be more complicated than getting that kind of permission in a more inviting atmosphere in the Western Pacific,\u201d Ralston said. \u201cAnd then you get the thing developed under say, three or four flights \u2014 now you\u2019ve proven it. Now you can move it back to Texas. So you kind of look for the path of least resistance and develop and establish capability and credibility, and with that you can back your claim that you are OK to go back to the FAA.\u201d It would be relatively easy to barge the landed Star\u00adships from a Pacific island back to Texas, he said. PMRF is the world\u2019s largest instrumented range capable of supporting surface, subsurface and space operations. The Navy said the facility has over 1,100 square miles of instrumented underwater range and over 42,000 square miles of controlled airspace. In August, U.S. Indo- Pacific Command said PMRF was \u201cin discussions (with SpaceX) for limited support and use of their range\u201d for the ocean touchdown.