SpaceX’s Super Heavy Booster Absent From Three Year FCC Test Grant Extension
Astronautic launch equipment manufacturer Space Exploration Technologies Corp. (SpaceX) has been granted a three-year extension in its license for conducting tests in the company's facilities in Boca Chica, Texas. The extension comes from the Federal Communications Commission (FCC) that has approved SpaceX's grant filed last week in the wake of its successful test flight of the Starship SN8 upper stage spacecraft test article.
Super Heavy's Absence From Grant & Request Does Not Mean No Test Flights For The Booster
The approval was granted yesterday with a notification emailed to SpaceX's representative today. It is needed due to SpaceX's need to communicate with its test articles while they're in flight. This communication is two-way, with the downlink enabling the company to monitor the prototype's performance while it is in flight, and the uplink enabling it to change parameters (such as orientation or engine throttle) in response to the data it receives.
While SpaceX's recent request filed last week or the initial request for the frequency usage filed in 2018 do not mention Starship by name (the only details they share are for 'Vertical Takeoff, Vertical Landing' (VTVL) vehicle) it's obvious that Starship testing is the subject of the original and renewal applications and the grant.
The extension also covers only the upper stage Starship spacecraft's testing, with this fact being made clear by the list of the frequencies that the FCC has approved. A presentation made by SpaceX to the commission in July shared four frequencies for Starship and four for the first stage booster dubbed Super Heavy. Out of the four for the spacecraft, two are mentioned explicitly and the other two are in close range of the ones shared with the regulatory body.
Yet, of the four for Super Heavy, none are either present directly or in a near range implying that perhaps SpaceX will resort to other procedures (such as a Special Temporary Authorization (STA)) to test the crucial rocket that will eventually be responsible for lifting the launch platform out of Earth's gravity. In other words just because the frequencies for the booster were not part of SpaceX's extension request (which follows the 2018 request verbatim), does not mean that its prototype will not be tested.
SpaceX is busy constructing the booster's prototypes in its Boca Chica facilities, but details for a potential test flight are scarce. Testing them will be difficult in certain aspects when compared to the SN8 test flight. While SpaceX will not have to test canards for its booster, as it will use standard grid fins similar to the Falcon 9 to orient itself for landing, the number of engines that will be present on this prototype might be larger than the ones present on SN8.
SpaceX tested SN8 with three of its Raptor engines, with engine reignition and the transition of fuel flow from the vehicle's primary tanks to the secondary tanks being key evaluation criteria for the flight. However, the number of engines that SpaceX will use in Super Heavy's prototype test is likely to be higher than this, but not too high.
SpaceX C.E.O. Mr. Elon Musk shared some details about this parameter during the Mars Society's 23rd Annual Convention in October. According to him, the initial flights will "just have maybe two to four engines" as his company might test the Raptors to their full thrust capacity to make up for the lack of engines and take the booster prototype to its full height.
A full-scale prototype of the booster will be 230 feet in height, according to details shared by SpaceX on its website, and the first full-scale prototype of the upper stage spacecraft/payload fairing unveiled by Musk last year was 164 feet tall. The final version of the booster will feature 28 engines, and given the complex processes of manufacturing them, Musk and his team are hesitant about conducting full-scale test flights before all major vehicle parameters are evaluated.