SpaceX considering SSTO Starship launches from Pad 39A

As SpaceX continues to make steady progress on multiple Starship test vehicles at their Boca Chica launch facility, the company’s CEO Elon Musk has confirmed that they are also constructing a Starship vehicle in Florida. The Florida based Starship is expected to launch from one of SpaceX’s Cape Canaveral based facilities, as opposed to the company’s launch site in Boca Chica, Texas. understands that one facility under serious consideration is historic Launch Complex 39A at Kennedy Space Center.

SpaceX hopes to use the Starship spacecraft to return humans to the moon and colonize Mars. While plans for the vehicle are rapidly evolving, at present multiple sources have indicated that the company is hoping to perform orbital test flights of the Starship prototypes through Single Stage to Orbit (SSTO) launches.

Such launches will see a Starship vehicle lift off from a SpaceX launch complex and go the entire way to orbit without any stage separation events. During operational missions, a Super Heavy first stage booster will be used to lift the Starship spacecraft a large portion of the way into orbit, as the additional performance will greatly increase the launch system’s payload capacity.

SpaceX workers construct a Starship prototype in Boca Chica Texas. Credit: NSF member BocaChicaGal

That being said, the Starship spacecraft has enough performance to reach orbit without the help of a Super Heavy booster. Therefore, during test flights designed to gain experience with critical flight regimes such as reentry, SpaceX is looking to execute SSTO launches.

However, the company first needs to build the Starship spacecraft’s that will launch into orbit.

This week, a forum member Zpoxy spotted a prototype vehicle under construction at Coastal Steel in Cocoa, Florida. SpaceX Musk then confirmed in a tweet that the construction was in fact Starship related.

Coastal Steel is a highly experienced fabricator with aerospace experience – having played an important role in the construction of NASA’s Mobile Launcher for the SLS rocket.

The Starship development at the facility includes the construction of an orbital prototype – similar to another vehicle being built in Boca Chica Texas.

Musk explained in subsequent tweets that the Texas and Florida based teams are competing to see which region is more effective at both producing the Starship vehicles.

Once construction is completed at the Coastal Steel facility, SpaceX will have to transport the vehicle to Cape Canaveral for launch. How exactly this will be done is not yet known.

If SpaceX chooses to transport the vehicle entirely by road, at least 12-14 miles of public roads will have to be navigated to get the vehicle onto NASA or Air Force Station property.

Furthermore, the Starship vehicle will be approximately 30 feet in diameter – assuming it is transported without landing legs – which may limit potential routes to the launch site.

However, as seen with Space Shuttle Endeavour, it is more than possible to transport a large spacecraft through city streets if the options are limited.

Shuttle Endeavour heads through the streets of LA on its way to the California Science Center. Credit: Sam Sun for NSF

In terms of where SpaceX will launch the Starship prototypes from Florida, it is understood that the company has been looking at their existing facilities to see if one of them could support the SSTO launches. Facilities under consideration have included the landing zones, SLC-40, and Pad 39A.

The Falcon 9’s SLC-40 launch site was apparently ruled out due to lack of space for expansion.

Furthermore, both of the landing zones are needed to support Falcon Heavy, and there is not much additional space on the perimeter. While the landing zones may still be a possibility, they are not currently the leading candidate.

Presently, Pad 39A is believed to be the favorite to support the early Starship missions. Nonetheless, it is important to note no formal decisions have been made and plans could change at any time.

Both of Kennedy Space Center’s launch complexes –  Pad 39A and Pad 39B launch – are very large, as they were built for the Apollo program. Thus, they have extra space that can potentially be used for additional launch platforms.

For instance, NASA has been looking at an additional pad for small satellite launch vehicles – designated Pad 39C – inside the perimeter of Pad 39B.

One proposal being looked at for Starship involves adding a second launch platform for Starship at Pad 39A along the existing ramp to the launch platform currently used by Falcon 9 and Falcon Heavy.

Such a design would allow Starship to potentially make use of existing infrastructure at the pad including the Horizontal Integration Facility (HIF) which was built for Falcon 9 and Falcon Heavy.

A conceptual render of what a Starship pad at 39A could look like by Jay DeShetler for NSF/L2 graphics artist Jay DeShelter has created a render of one potential concept for a Starship launch platform at Pad 39A. While details of the plans are currently limited (and heavily subjected to change), it is understood that the approximate placement of the additional launch mount is inline with at least one proposal.

Starship may also be able to capitalize on existing ground infrastructure including the LOX tanks at the pad.

However, on the propellant side, Starship will use methane instead of kerosene like Falcon 9 and Falcon Heavy. Therefore, the installation of methane tanks and associated infrastructure will certainly be a requirement.

Luckily, there is plenty of space at the pad to make room for such hardware including the area that was once used to store hydrogen for the Space Shuttle era.

On the Boca Chica Texas side, designs for a launch pad will be more straightforward. The company already owns a launch site which was originally going to be used to support Falcon 9 and Falcon Heavy.

That being said, the Falcon plans never materialized and thus the company has been actively construction a Starship launch facility on a clean plot of land.

The Boca Chica facility has already supported two tethered hot firings of a prototype Starship hopper using a single Raptor engine. The teams are now pressing ahead with an untethered test campaign which is expected to see a hop as high as 20 meters in the coming weeks.

To prepare of the higher altitude hops, the hopper has received numerous modifications over the past month including the addition of Altitude Control System thrusters which appear to be identical to the ones used on Falcon 9. These thrusters will help orientate the Starship vehicle during flight.

Once SpaceX is back into the Starship test campaign, the flights will continue to shoot for higher and higher altitudes until a Starship vehicle is eventually launched into orbit.

If SpaceX does manage to execute a successful SSTO Starship launch, it will be the first time that a rocket has ever launched from Earth into orbit without separating stages. Many concepts have attempted to do so including the Delta Clipper and Lockheed Martin X-33. However, those programs were canceled before reaching orbit.

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