The next-generation Starship launch vehicle platform developed by Space Exploration Technologies Corp. (SpaceX) is being used by the National Aeronautics and Space Administration (NASA) to investigate surface temperatures on vehicles moving at speeds greater than the speed of sound.
Following a scheduled orbital test flight next year, the program, known by NASA as the Scientifically Calibrated In-Flight Imagery (SCIFLI) program, will employ a NASA aircraft to examine Starship and its heat tiles as the spacecraft reenters the Earth’s atmosphere. The information was disclosed in a presentation given by NASA’s Langley Research Center, which was picked up by SpaceX fans on the social media site Reddit who were paying close attention.
Both NASA and SpaceX have revealed a few information in the brief presentation, which is comprised of just two slides, about their respective intentions for monitoring Starship as it renters the upper atmosphere of the Earth and their respective ambitions to build the world’s first completely reusable spaceship.
At NASA’s end, the space agency will develop a new imaging system that it refers to as “A high-resolution observation during reentry using calibrated infrared cameras will be used to monitor surface temperature of the entire lower surface of the Starship spacecraft during hypersonic reentry.”
This extract refers to the upper stage of a 120-meter-tall spaceship that will be responsible for ferrying people and cargo to a variety of locations, including the lunar and Martian surfaces. The Super Heavy is the name given to the vehicle’s bottom stage, while the vehicle’s upper and lower stages are together referred to as the Starship.
The imaging equipment will be transported by NASA’s WB-57 aircraft, which will be based at the Johnson Space Center in Houston, Texas, and managed by the agency. SpaceX missions such as the Dragon DM-1 mission in 2019, which tested SpaceX’s Crew Dragon capsule before the DM-2 mission, which flew astronauts Robert Behnken and Douglas Hurley and resumed flights to the International Space Station (ISS) from U.S. soil a year later, have all been observed by this aircraft in the past.
The aircraft can fly up to 60,000 feet above sea level and has a range of 2,500 miles, with a cargo capacity of 8,800 pounds. It can travel at heights up to 60,000 feet above sea level.
The presentation relates to a new camera system that NASA will develop specifically to monitor Starship during atmospheric reentry. This system is called SAMI (SCIFLI Airborne Multispectral Imager), and NASA Langley describes it as:
To perform the thermal observation, the NASA is developing an advanced multispectral imaging system that will be flown on a NASA high- altitude WB-57F research aircraft. The resulting calibrated measurements will inform modeling efforts and anchor surface temperatures inferred from embedded thermocouples.
The space agency then shares important details about Starship’s heat shield tiles, which are referred to as Thermal Protection System (TPS) tiles in the aerospace world. This reveal comes a handful of days after SpaceX’s director Dragon mission management Ms. Sarah Walker shared her company’s ongoing research into reusing the heat shield components for its operational Dragon spacecraft. During a NASA press conference, Ms. Walker confirmed that her company had already reused a lamenting material for the spacecraft’s body.
SpaceX’s Dragon spacecraft is not fully reusable, as the company has to add new heat shield tiles to each spacecraft before a new mission. This is because the tiles are partially ablative, which means that they dissipate heat by shedding their mass during reentry.
However, NASA’s Space Shuttle used a different variant of heat shield tiles, which were fully reusable. These tiles do not shed their mass during reentry. Instead, they work by transferring the heat to the surrounding environment through convection. The Shuttle’s mission profile aimed to target and return from altitudes only as high as 550 kilometers, also known as the Low Earth Orbit (LEO).
Therefore, it could have afforded to use the reusable, non-ablative heat shield tiles, which is a luxury that Starship cannot afford since it is designed to be an interplanetary transport vehicle.
Through the SAMI program, NASA hopes to let SpaceX drastically reduce the launch costs of the Starship program. SpaceX’s chief Mr. Elon Musk has also mentioned low costs several times, with the executive hoping that a 150-ton Starship launch to LEO will cost as low as $1.5 million, resulting in a per-kilogram cost of $10.
For comparison, through its rideshare program that uses the Falcon 9 rocket, SpaceX gives potential customers an estimate of $1 million for payloads as heavy as 200 kilograms. This results in a cost to LEO of $5,000. It also outlines the sheer optimism which fuels Mr. Musk’s goal of eventually making humans an interplanetary species. The $10/kg estimate assumes an aggressive launch cadence, which will only be established once the Starship program has matured and is fully operational.
Meanwhile, SpaceX will have to amortize its development expenses and contracts to LEO and lunar orbit, while its satellite internet service Starlink will serve as a means of recovering some of its initial investment in infrastructure. Musk has shown interest in performing a point-to-point hypersonic flight test for point-to-point travel around the Earth at speeds beginning at 3,000 miles per hour. The Federal Aviation Administration (FAA) is presently conducting an Environmental Assessment for Starship’s launch facilities at Boca Chica, Texas.