Spaceflight Insider

Musk teases Starship in round of Twitter posts

SpaceX Starship Big Falcon Rocket image credit SpaceX

Illustration of Starship/Big Falcon Rocket released by SpaceX as the company prepares to test the massive new vehicle. Image Credit: SpaceX

Among a deluge of Tesla and The Boring Company tweets, SpaceX’s founder, CEO and chief rocket designer Elon Musk teased the latest about the Big Falcon Rocket “Starship.”

Although keeping the original name for the Big Falcon Rocket might have generated controversy in what goes into naming a rocket (the meaning behind the “F” sparked some debate), Musk’s latest tweets have touched onto something far more substantial — what this new rocket will be comprised of.

In the case of the newly-dubbed Starship itself, that material appears to be stainless steel. While the stainless steel is nothing new, having been invented in 1913 by Henry Brearly. Musk noted the positive aspects of the material in a Dec. 24, 2018 tweet: “Usable strength/weight of full hard stainless at cryo is slightly better than carbon fiber, room temp is worst, high temp is vastly better.”

SpaceX Starship Big Falcon Rocket image courtesy of SpaceX Elon Musk

Image tweeted by SpaceX’s Elon Musk of test hardware that will be used to prepare the new Starship vehicle for eventual orbital flight. Photo Credit: Elon Musk / SpaceX

So what type of paint has Musk selected to cover the massive new vehicle? None. “Skin will get too hot for paint. Stainless mirror finish. Maximum reflectivity.”

When it comes to the temperatures a vehicle encounters when it re-enters Earth’s atmosphere (NASA’s now-retired fleet of shuttle orbiters encountered extremes of up to 3,000 degrees Fahrenheit / 1,649 degrees Celsius), it is critical its shielding be up to the job. For this task, it appears Starship might use a regeneratively-cooled heat shield.

The heat tiles used on NASA’s fleet of space shuttles (designed and built by Rockwell International) were designed to last for the planned life of each orbiter — 100 missions. The shuttle also used thermal blankets and other systems and procedures to reduce the stress of interfacing with the atmosphere.

Heat shields used on past spacecraft have been mostly single-use. Ablative heat shields for example burned away, taking the heat with it. This type of protective system was used on NASA’s Mercury, Gemini and Apollo spacecraft.

Musk discussed using regeneratively-cool protection Starship by stating: “Leeward side needs nothing, windward side will be activity cooled with residual (cryo) liquid methane, so will appear liquid silver even on hot side.”

SpaceX has benefited from materials developed by NASA for thermal protection. The most obvious being PICA-X which is a derivative of NASA’s Phenolic Impregnated Carbon Ablator (PICA) heat shield. 

Just as was done on NASA’s shuttle, Starship’s rocket engines will have to be protected during the critical period of reentry. Musk appeared to be considering the matter in a tweet on Christmas in response to questions he was asked: “No, Raptors must be shielded during atmospheric entry. Although, maybe not …” Musk said that three raptor engines would be used for the test “hopper” flights which could take place as early as 2019.

Starship is a vehicle that has undergone several design changes which prompted a question regarding how late design changes appear to be enabling the company to produce Starship more quickly. Musk said he’d address how this process works sometime in the March/April time frame. He also claimed these changes could provide a 60 percent chance that Starship could be in orbit as early as 2020.

As was noted by Tech Explorist’s Amit Malewar, the Big Falcon Rocket system would use a 219-foot (67 meters) tall rocket booster that Musk has referred to as the “Super Heavy.”

Video posted on YouTube by Scott Manley




Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology,, The Mars Society and Universe Today.

Reader Comments – fatigue, work hardens, cracks’ fails

James Lunar Miner

The grossly inefficient 380 Isp of the fossil fueled Big Falcon Rocket/Starship system means it would require us to endlessly haul enormous amounts of low performance and low energy fossil propellant up through the Earth’s fragile atmosphere and contribute to increasing our atmosphere’s CO2’s level.

Maybe we need a far higher Isp and thus more propellant efficient propulsion systems to efficiently get humans and large amounts of cargo to the Moon, asteroids, and Mars.

The powerful SLS will probably be used to launch reusable 130 ton (and propellant efficient and cost effective) 900+ Isp Nuclear Thermal Propulsion (NTP) powered Lunar, asteroid, and Martian Landers and other large NTP powered spacecraft.

“‘As we push out into the solar system, nuclear propulsion may offer the only truly viable technology option to extend human reach to the surface of Mars and to worlds beyond,’ said Sonny Mitchell, Nuclear Thermal Propulsion project manager at Marshall. ‘We’re excited to be working on technologies that could open up deep space for human exploration.’”

And, “An NTP system can cut the voyage time to Mars from six months to four and safely deliver human explorers by reducing their exposure to radiation. That also could reduce the vehicle mass, enabling deep space missions to haul more payload.”

From: “NASA Contracts with BWXT Nuclear Energy to Advance Nuclear Thermal Propulsion Technology”

SLS will produce less CO2 as it has never flown and will only fly once.

James Lunar Miner

The 3,000 Isp to 14,000+ Isp of various solar electric propulsion systems are far more propellant efficient than the low 380 Isp of the grossly propellant inefficient upper stage of the Big Falcon Rocket/Starship system.


“The Solar Electric Propulsion project has developed solar arrays that are lighter, stronger, more compact, and less expensive than those currently available.”

And, “Solar electric propulsion provides such high fuel economy that it reduces the amount of propellant required onboard vehicles for deep-space missions by as much as 90 percent.”

From: “Solar Electric Propulsion (SEP)”


With much more propellant efficient nuclear thermal propulsion systems and super propellant efficient solar electric propulsion systems, maybe no one really wants or needs the endless CO2 pollution or costly low Isp and gross propellant inefficiency of a fossil fuel rocket powered Starship!

It is EM’s great idea to put AIs on Mars surface. AIs could be used to make planet Mars habitable in future, by converting Ice cores into water on Mars as well as for artificial raining or bringing water from other moons/ planets also, using advanced spacecrafts.

Most people live in a gravity well (earth, mars, moon, etc.)so chemical rockets are needed to leave. This will be the case for at least 50 years.

James Lunar Miner

Nuclear thermal powered Landers can and should be used on the Moon, asteroids, Ceres, and various moons across the Solar System.

Obviously, for the critical task of getting into LEO we will probably use 430 to 451 Isp hydrolox rocket engine based launchers similar to the Japanese H-3, and the Delta IV Heavy, Boeing’s reusable SSME/AR-22 powered XS-1 Phantom Express, and NASA’s SSME powered SLS for a long time into the future.

Electromagnetic based launch assist systems on the Moon, Earth, asteroids, and Mars are also likely to be used.

If we want to not buy space rides or pay Lunar cargo shipping fees to China, India, Russia, or some other nation, perhaps the real issue is avoiding the cult nonsense of ‘Mars colonies soon’ based on costly, CO2 polluting, and grossly propellant inefficient 380 Isp fossil fuel powered launchers and space bombers.


“Russia Might Actually Build a Nuclear-Powered Rocket”
By Avery Thompson 11/16/2018

“Elon Musk is using the existing tech, developed a long time ago. He is a businessman: he took a solution that was already there, and applied it successfully.””
Very successfully!

“Russia Might Actually Build a Nuclear-Powered Rocket”
By Avery Thompson 11/16/2018

It works now; versus fantasy rocket systems…

James Lunar Miner

We need new and much more efficient and higher performance technology than what Mr. Elon Musk is offering to sell.

Mr. Elon Musk’s overweight, fossil fueled, and propellant inefficient 380 Isp BFR/Starship/space bomber will be a large flying carbon belching smokestack in a time where zero CO2 manufacturing and transportation systems and high carbon taxes and far more propellant efficient high 900 to 14,000+ Isp spacecraft will probably be the norm.

“‘Earth’s climate is now changing faster than at any point in the history of modern civilization, primarily as a result of human activities,’ says the report, which was filed on behalf of 13 different federal agencies.”

And, “The impacts of global climate change are already being felt in the United States and are projected to intensify in the future—but the severity of future impacts will depend largely on actions taken to reduce greenhouse gas emissions and to adapt to the changes that will occur.”

From: “Federal report says climate change will wallop U.S. economy” By Dareh Gregorian Nov. 23, 2018

See also:

“The Rationale/Benefits of Nuclear Thermal Rocket Propulsion for
NASA’s Lunar Space Transportation System”

By Stanley K. Borowski Lewis Research Center 1991
NASA TechnicalMemorandum 106739 AIAA-91-2052

NASA abandoned this approach 30 years ago for a reason. Musk is still way ahead of everyone else.

“The Rationale/Benefits of Nuclear Thermal Rocket Propulsion for
NASA’s Lunar Space Transportation System”

By Stanley K. Borowski Lewis Research Center 1991
NASA TechnicalMemorandum 106739 AIAA-91-2052

James Lunar Miner

American, Russian, Chinese, European, Japanese, and other smart and serious space folks all around the Home Planet want and need the cost effectiveness, high propellant efficiency, increased cargo capacity, and spaceflight risk reductions offered by reusable 900+ Isp nuclear thermal rocket engine powered spacecraft.

“For the Space Launch System vehicle currently under development, an additional beyond-LEO engine for interplanetary travel from Earth orbit to Mars orbit, and back, is being studied as of 2013 at Marshall Space Flight Center with a focus on nuclear thermal rocket (NTR) engines.[8]”

And, “In historical ground testing, NTRs proved to be at least twice as efficient as the most advanced chemical engines, allowing quicker transfer time and increased cargo capacity. The shorter flight duration, estimated at 3–4 months with NTR engines,[9] compared to 8–9 months using chemical engines,[10] would reduce crew exposure to potentially harmful and difficult to shield cosmic rays.[11][12][13][14]”

And, “NTR engines, such as the Pewee of Project Rover, were selected in the Mars Design Reference Architecture (DRA).[12][15][16][17]”

From: “NERVA” Wikipedia

SLS will likely fly only once. NTR simply don’t exist as a tested and usable technology. At NASA rate of development, it won’t for another 50 years. It’s fantasy hardware.

““For the Space Launch System vehicle currently under development, an additional beyond-LEO engine for interplanetary travel from Earth orbit to Mars orbit, and back, is being studied as of 2013 at Marshall Space Flight Center with a focus on nuclear thermal rocket (NTR) engines.[8]”
From: “NERVA” Wikipedia

James Lunar Miner

“This led to the creation of the NRX/XE, a nuclear-thermal engine which the SNPO certified as having met the requirements for a crewed mission to Mars.”

And, “The Soviet Union conducted similar studies during the 1960s, hoping to use them on the upper stages of of their N-1 rocket. Despite these efforts, no nuclear rockets ever entered service, owing to a combination of budget cuts, loss of public interest, and a general winding down of the Space Race after the Apollo program was complete.”

And, “In 2014, Dr. Houts conducted a presentation outlining how bimodal rockets (and other nuclear concepts) represented ‘game-changing technologies for space exploration’. As an example, he explained how the Space Launch System (SLS) – a key technology in NASA’s proposed crewed mission to Mars – could be equipped with chemical rocket in the lower stage and a nuclear-thermal engine on the upper stage.”

From: “NASA Reignites Program for Nuclear Thermal Rockets”
By Matt Williams August 14, 2017

The SLS, Long March 9, and Soyuz-5 Super Heavy will probably be launching far more mission capable, large, 130+ ton, 900+ Isp, highly propellant efficient, cost effective, and reusable nuclear thermal powered upper stages long after the grossly propellant inefficient 380 Isp fossil fueled BFR/starship/space bomber has become an ignored footnote in history books.

James Lunar Miner

If there is proper financial support from Congress, NASA could be ready to fly nuclear thermal rocket (NTR) engines on an upper stage of the SLS in the 2020s.

“As mentioned previously, NTP was selected as the preferred
propulsion option in NASA’s recent Mars DRA 5.0 study.
With its high thrust and “factor of 2” higher specific
impulse over chemical propulsion, the use of NTP helped
reduce the required launch mass for DRA 5.0 by over 400 t
– the equivalent mass of the International Space Station.”

And, “Finally, and most importantly, NASA restarted an NTP
technology development and demonstration effort in FY’ 1 1
that includes Foundational Technology Development work
in the five key task areas discussed above. The results from
these tasks will provide the basis for continuing work in
these same areas under the Nuclear Cryogenic Propulsion
Stage (NCPS) project in FY’s 12 – 14. This effort will be
followed by system-level Technology Demonstrations that
include ground testing a small, scalable NTR before 2020,
with a flight test shortly thereafter.”

From: “Nuclear Thermal Propulsion (NTP): A Proven Growth
Technology for Human NEO / Mars Exploration Missions”
By Stanley K. Borowski, David R. McCurdy, and Thomas W. Packard 2012

James Lunar Miner

Highly propellant efficient and 900+ Isp nuclear thermal rocket engine powered spacecraft launched on the Space Launch System will soon make technologically obsolete the grossly propellant inefficient, overweight, and fossil fueled 380 Isp Raptor rocket engine powered BFR/Starship.


Of that total, $180 million will go to Restore-L, a satellite servicing mission also previously threatened with cancellation, and $100 million to nuclear thermal propulsion research, including planning for a flight demonstration mission by 2024.”

From: “Final fiscal year 2019 budget bill secures $21.5 billion for NASA”
By Jeff Foust 2/17/2019

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