Sustaining long-term human exploration on the Moon will require the safe and affordable transportation of crew and significant amounts of cargo.
NASA announced it has modified its contract with SpaceX to further develop the Starship human landing system. Initially selected to develop a lunar lander capable of carrying astronauts between lunar orbit and the surface of the Moon as part of NASA’s Artemis III mission—marking humanity's first return to the Moon since the Apollo program’s final mission in 1972—SpaceX will now support a second human landing demonstration as part of NASA's Artemis IV mission. Additionally, SpaceX will demonstrate Starship’s capability to dock with Gateway, a small space station that will orbit the Moon in efforts to support both lunar and deep-space exploration, accommodate four crew members, and deliver more supplies, equipment, and science payloads that are needed for extensive surface exploration.
SpaceX’s Starship spacecraft and Super Heavy rocket represent an integrated and fully reusable launch, propellant delivery, rendezvous, and planetary lander system with robust capabilities and safety features uniquely designed to deliver these essential building blocks. We are honored to be a part of NASA’s Artemis Program to help return humanity to the Moon and usher in a new era of human space exploration.
Dennis and Akiko Tito are the first two crewmembers announced on Starship’s second commercial spaceflight around the Moon. This will be Dennis’ second mission to space after becoming the first commercial astronaut to visit the International Space Station in 2001, and Akiko will be among the first women to fly around the Moon on a Starship. The Titos joined the mission to contribute to SpaceX’s long-term goal to advance human spaceflight and help make life multiplanetary.
Over the course of a week, Starship and the crew will travel to the Moon, fly within 200 km of the Moon’s surface, and complete a full journey around the Moon before safely returning to Earth. This mission is expected to launch after the Polaris Program’s first flight of Starship and dearMoon.
SpaceX’s Chief Engineer Elon Musk and T-Mobile’s CEO and President Mike Sievert announced today a breakthrough plan to provide truly universal cellular connectivity.
Despite powerful LTE and 5G terrestrial wireless networks, more than 20% of the United States land area and 90% of the Earth remain uncovered by wireless companies. These dead zones have serious consequences for remote communities and those who travel off the grid for work or leisure. The telecom industry has struggled to cover these areas with traditional cellular technology due to land-use restrictions (e.g. National Parks), terrain limits (e.g. mountains, deserts and other topographical realities) and the globe’s sheer vastness. In those areas, people are either left disconnected or resort to lugging around a satellite phone and paying exorbitant rates.
Leveraging Starlink, SpaceX’s constellation of satellites in low Earth orbit, and T-Mobile’s wireless network, the companies are planning to provide customers text coverage practically everywhere in the continental US, Hawaii, parts of Alaska, Puerto Rico and territorial waters, even outside the signal of T-Mobile’s network. The service will be offered starting with a beta in select areas by the end of next year after SpaceX’s planned satellite launches. Text messaging, including SMS, MMS, and participating messaging apps, will empower customers to stay connected and share experiences nearly everywhere. Afterwards, the companies plan to pursue the addition of voice and data coverage.
In addition, Elon and Mike shared their vision for expanding Coverage Above and Beyond globally, issuing an open invitation to the world’s carriers to collaborate for truly global connectivity. T-Mobile committed to offer reciprocal roaming to those providers working with them to enable this vision.
This service will have a tremendous impact on the safety, peace of mind, and individual and business opportunities around the globe. The applications range from connecting hikers in national parks, rural communities, remote sensors and devices, and people and devices in emergency situations, such as firefighters.
This satellite-to-cellular service will provide nearly complete coverage anywhere a customer can see the sky—meaning you can continue texting and eventually make a cell phone call even when you leave terrestrial coverage. We’ve designed our system so that no modifications are required to the cell phone everyone has in their pocket today, and no new firmware, software updates, or apps are needed. As a complementary technology to terrestrial networks, SpaceX can enable mobile network operators to connect more people, fulfill coverage requirements, and create new business opportunities.
If you represent a mobile network operator or regulatory agency and are interested in partnering with SpaceX to bring this new level of mobile connectivity to your region, please reach out to us at direct2cell@spacex.com.
SpaceX was founded to revolutionize space technology towards making life multiplanetary. SpaceX is the world’s leading provider of launch services and is proud to be the first private company to have delivered astronauts to and from the International Space Station (ISS), and the first and only company to complete an all-civilian crewed mission to orbit. As such, SpaceX is deeply committed to maintaining a safe orbital environment, protecting human spaceflight, and ensuring the environment is kept sustainable for future missions to Earth orbit and beyond.
SpaceX has demonstrated this commitment to space safety through action, investing significant resources to ensure that all our launch vehicles, spacecraft, and satellites meet or exceed space safety regulations and best practices, including:
Designing and building highly reliable, maneuverable satellites that have demonstrated reliability of greater than 99%
Operating at low altitudes (below 600 km) to ensure no persistent debris, even in the unlikely event a satellite fails on orbit
Inserting satellites at an especially low altitude to verify health prior to raising into their on-station/operational orbit
Transparently sharing orbital information with other satellite owners/operators
Developed an advanced collision avoidance system to take effective action when encounter risks exceed safe thresholds
With space sustainability in mind, we have pushed the state-of-the-art in key technology areas like flying satellites at challenging low altitudes, the use of sustainable electric propulsion for maneuvering and active de-orbit, and employing inter-satellite optical communications to constantly maintain contact with satellites. SpaceX is striving to be the world’s most open and transparent satellite operator, and we encourage other operators to join us in sharing orbital data and keeping the public and governments updated with detailed information about operations and practices.
SpaceX continues to innovate to accelerate space technologies, and we are currently providing much-needed internet connectivity to people all over the globe, including underserved and remote parts of the world, with our Starlink constellation. Below are our operating principles demonstrating our commitment to space sustainability and safety.
Designing and Building Safe, Reliable and Demisable Satellites
SpaceX satellites are designed and built for high reliability and redundancy in both supply chain and satellite design to successfully carry out their five-year design life. Rigorous part and system-level screening and testing enable us to reliably build and launch satellites at very high rates. We have the capacity to build up to 45 satellites per week, and we have launched up to 240 satellites in a single month. This is an unprecedented rate of deployment for a complex space system — and reflects SpaceX’s commitment to increase broadband accessibility around the world with Starlink as soon as feasible.
The reliability of the satellite network is currently higher than 99% following the deployment of over 2,000 satellites, where only 1% have failed after orbit raising. We de-orbit satellites that are at risk of becoming non-maneuverable to prevent dead satellites from accumulating in orbit. Although this comes at the cost of losing otherwise healthy satellites, we believe this proactive approach is the right thing for space sustainability and safety.
Our satellites use multiple strategies to prevent debris generation in space: design for demise, controlled deorbit to low altitudes, low orbit insertion, low operating orbit, on-board collision avoidance system, reducing the chance small debris will damage the satellite with a low profile satellite chassis and using Whipple shields to protect the key components, reducing risk of explosion with extensive battery pack protection, and failure modes that do not create secondary debris.
SpaceX satellites are propulsively deorbited within weeks of their end-of-mission-life. We reserve enough propellant to deorbit from our operational altitude, and it takes roughly 4 weeks to deorbit. Once the satellites reach an appropriate altitude, we coordinate with the 18th Space Control Squadron. Once coordinated, we initiate a high drag mode, causing the satellite’s velocity to reduce sufficiently that the satellite deorbits. The satellites deorbit quickly from this altitude, depending on atmospheric density. SpaceX is the only commercial operator to have developed expertise in flying in a controlled way in this low altitude, high drag environment, which is incredibly difficult and required a significant investment in specialized satellite engineering. SpaceX made these investments so that we can maintain controlled flight as long as possible prior to deorbit, providing us with the ability to perform any necessary maneuvers to further reduce collision risk.
When a satellite’s altitude decays, it encounters a constantly increasing atmospheric density. Initially, these molecules impact the satellite, but as the air density increases, a high-pressure shock wave forms in front of the spacecraft. As the satellite slows down and descends into the atmosphere, its orbital energy is transferred into the air, heating it to a plasma. The hot plasma sheath envelops the satellite, causing intense heating. Starlink satellites are designed to demise as they reenter the Earth’s atmosphere, meaning they pose no risk to people or property on the ground. Design for demise required the investment of significant engineering resources and often required adding cost and even mass to our satellites, such as our decision to use aluminum rather than composite overwrap pressure vessels for the fuel tank for our propulsion system. SpaceX has safely deorbited over 200 satellites utilizing this approach. By building reliable, debris minimizing satellites, planning for active deorbit and designing for full demisability, we ensure we’re keeping space sustainable and safe.
Extremely Low Orbit Insertion
In addition to SpaceX designing and building very reliable satellites, we further mitigate risks by deploying the satellites into extremely low orbits relative to industry standards. We deploy our satellites into low altitudes (<350km) and use our state-of-the-art electric propulsion thruster to boost the satellites to the operational altitude of approximately 550 km to start their mission. We leverage SpaceX’s technical advancements to maintain controlled flight at these low altitudes. By deploying the satellites into such low altitudes, in the rare case where any SpaceX satellite does not pass initial system checkouts, it is quickly and actively deorbited using its thruster or passively by atmospheric drag. This approach is not without complexity or other challenges. This was best evidenced by the recent February 3rd Starlink launch, after which increased drag from a geomagnetic storm resulted in the premature deorbit of 38 satellites. Despite such challenges, SpaceX firmly believes that a low insertion altitude is key for ensuring responsible space operations.
Operating Below 600 km
SpaceX operates its satellites at an altitude below 600 km because of the reduced natural orbit decay time relative to those above 600 km. Starlink operates in "self-cleaning" orbits, meaning that non-maneuverable satellites and debris will lose altitude and deorbit due to atmospheric drag within 5 to 6 years, and often sooner, see Fig. 1. This greatly reduces the risk of persistent orbital debris, and vastly exceeds the FCC and international standard of 25 years (which we believe is outdated and should be reduced). Natural deorbit from altitudes higher than 600 km poses significantly higher orbital debris risk for many years at all lower orbital altitudes as the satellite or debris deorbits. Several other commercial satellite constellations are designed to operate above 1,000 km, where it requires hundreds of years for spacecraft to naturally deorbit if they fail prior to deorbit or are not deorbited by active debris removal, as in Fig. 1. SpaceX invested considerable effort and expense in developing satellites that would fly at these lower altitudes, including investment in sophisticated attitude and propulsion systems. SpaceX is hopeful active debris removal technology will be developed in the near term, but this technology does not currently exist.
Fig. 1: Orbital lifetime for a satellite with a mass-to-area ratio of 40kg/m2 at various starting altitudes and average solar cycle.
Fig. 2 shows debris as a function of each altitude. The debris generated from collision events from satellites flying at altitudes above 600km will stay in orbit for decades to come and create orbital debris risk for each altitude they pass through as they deorbit.
Fig. 2: Debris per 1-km altitude shell as a function of orbital altitude.
Transparency and Data Sharing
SpaceX transparently and continuously shares the details of our Starlink network both with governments and other satellite owners/operators. We work to ensure accurate, relevant, and up-to-date information related to space safety, and space situational awareness is shared with all operators. SpaceX shares high fidelity future position and velocity prediction data (ephemerides) for all SpaceX satellites.
SpaceX shares both propagated ephemerides and covariance (statistical uncertainty of the predictions) data on Space-Track.org and encourages all other operators to do so, as this enables more meaningful and accurate computation of collision risks. SpaceX is also working to make it even easier for anyone to access our ephemerides by eliminating any requirement to login to Space-Track.org to see our data.
In addition to providing our satellite ephemerides, SpaceX volunteered to provide routine system health reports to the Federal Communications Commission ("FCC"), something no other operator has ever offered or currently does. These reports indicate the status of our constellation, including a summary of the operational status of our satellite fleet, and the number of maneuvers performed to reduce the collision probability with other objects. Fig. 3 is a sample of the number of maneuvers Starlink has done over the 6-month period from June 2021 through November 2021.
Fig. 3: Number of SpaceX maneuvers from July-Dec 2021 (total was 3300)
Collision Avoidance System
SpaceX has high fidelity location and prediction data for our satellites from deployment through end-of-life disposal, and we share this information continuously with the U.S. Space Force, LeoLabs and other operators for tracking and collision avoidance screening. SpaceX satellites regularly downlink accurate orbital information from onboard GPS. We use this orbital information, combined with planned maneuvers, to accurately predict future ephemerides, which are uploaded to Space-Track.org three times per day. LeoLabs downloads our ephemerides from Space-Track.org and along with the U.S. Space Force's 18th Space Control Squadron screens these trajectories against other satellites and debris to predict any potential conjunctions. Such conjunctions are communicated back to SpaceX and other satellite owners/operators as Conjunction Data Messages (CDMs), which include satellite state vectors, position uncertainties, maneuverability status, and the owner/operator information. SpaceX uploads these CDMs to applicable SpaceX satellites.
To accomplish safe space operations in a scalable way, SpaceX has developed and equipped every SpaceX satellite with an onboard, autonomous collision avoidance system that ensures it can maneuver to avoid potential collisions with other objects. If there is a greater than 1/100,000 probability of collision (10x lower than the industry standard of 1/10,000) for a conjunction, satellites will plan avoidance maneuvers. When planning a maneuver for any conjunction, the satellites take care to avoid inadvertently increasing risk for other conjunctions above the same threshold.
By default, Starlink satellites assume maneuver responsibility for all conjunction events. Upon receipt of a high-probability conjunction with another maneuverable satellite, SpaceX coordinates with the other operator. SpaceX operators are on-call 24/7 to coordinate and respond to inquiries from other operators; contact information for high-urgency requests is available to other operators via Space-Track.org. If the other operator prefers to take maneuver responsibility themselves, Starlink satellites can be commanded to not maneuver for an event.
In addition to collision avoidance maneuvers, Starlink satellites can autonomously “duck” for conjunctions, orienting their attitude to have the smallest possible cross-section (like the edge of a sheet of paper) in the direction of the potential conjunction, reducing collision probability by another 4-10x (see Fig. 4).
Fig. 4: SpaceX’s “duck” maneuver (right) minimizing area in potential collision direction (out of page) compared with worst-case orientation (left)
SpaceX’s collision avoidance system has been thoroughly reviewed by NASA’s Conjunction Assessment and Risk Analysis (CARA) program under a Space Act Agreement (SAA) with NASA, and per the SAA, NASA relies on it to avoid collisions with NASA science spacecraft.
SpaceX satellites’ flight paths are designed to avoid inhabited space stations like the International Space Station (ISS) and the Chinese Space Station Tiangong by a wide margin. We work directly with NASA and receive ISS maneuver plans to stay clear of their current and planned trajectory including burns. China does not publish planned maneuvers, but we still make every effort to avoid their station with ISS-equivalent clearance based on publicly available ephemerides.
SpaceX is proud of our sophisticated and constantly improving design, test, and operational approach to improve space sustainability and safety, which are critical towards accelerating space exploration while bringing Internet connectivity to the globe. We urge all satellite owner/operators to make similar investments in sustainability and safety and make their operations transparent. We encourage all owner/operators to generate high quality propagated ephemeris and covariance for screening by the 18th Space Control Squadron and to openly share this information with others to maximize coordination to ensure a sustainable and safe space environment for the future. Ultimately, space sustainability is a technical challenge that can be effectively managed with the appropriate assessment of risk, the exchange of information, and the proper implementation of technology and operational controls. Together we can ensure that space is available for humanity to use and explore for generations to come.
Jared Isaacman, founder and CEO of Shift4 who commanded the Inspiration4 mission, announced today the Polaris Program, a first-of-its-kind effort to rapidly advance human spaceflight capabilities, while continuing to raise funds and awareness for important causes here on Earth. The program will consist of up to three human spaceflight missions that will demonstrate new technologies, conduct extensive research, and ultimately culminate in the first flight of SpaceX’s Starship with humans on board.
The first mission, Polaris Dawn, is targeted to launch no earlier than the fourth quarter of 2022 from historic Launch Complex 39A at NASA’s Kennedy Space Center in Florida. This Dragon mission will take advantage of Falcon 9 and Dragon’s maximum performance, flying higher than any Dragon mission to date and endeavoring to reach the highest Earth orbit ever flown. Dragon and the Polaris Dawn crew will spend up to five days in orbit, during which the crew will attempt the first-ever commercial spacewalk, conduct scientific research designed to advance both human health on Earth and our understanding of human health during future long-duration spaceflights, and be the first crew to test Starlink laser-based communications in space, providing valuable data for future space communications systems necessary for missions to the Moon, Mars, and beyond.
The Polaris Dawn mission has many first-time objectives, so the Polaris Program chose a crew of experts who know each other well and have a foundation of trust they can build upon as they undergo the challenges of this mission. In addition to Isaacman, the crew includes Scott “Kidd” Poteet, a veteran member of Jared’s team, and two SpaceX employees, Sarah Gillis and Anna Menon.
On Thursday, February 10 from Starbase in Texas, SpaceX Chief Engineer Elon Musk provided an update on the development of Starship, a fully reusable transportation system capable of carrying passengers and cargo to Earth orbit, the Moon, Mars, and beyond.
On Thursday, February 3 at 1:13 p.m. EST, Falcon 9 launched 49 Starlink satellites to low Earth orbit from Launch Complex 39A (LC-39A) at Kennedy Space Center in Florida. Falcon 9’s second stage deployed the satellites into their intended orbit, with a perigee of approximately 210 kilometers above Earth, and each satellite achieved controlled flight.
SpaceX deploys its satellites into these lower orbits so that in the very rare case any satellite does not pass initial system checkouts it will quickly be deorbited by atmospheric drag. While the low deployment altitude requires more capable satellites at a considerable cost to us, it’s the right thing to do to maintain a sustainable space environment.
Unfortunately, the satellites deployed on Thursday were significantly impacted by a geomagnetic storm on Friday. These storms cause the atmosphere to warm and atmospheric density at our low deployment altitudes to increase. In fact, onboard GPS suggests the escalation speed and severity of the storm caused atmospheric drag to increase up to 50 percent higher than during previous launches. The Starlink team commanded the satellites into a safe-mode where they would fly edge-on (like a sheet of paper) to minimize drag—to effectively “take cover from the storm”—and continued to work closely with the Space Force’s 18th Space Control Squadron and LeoLabs to provide updates on the satellites based on ground radars.
Preliminary analysis show the increased drag at the low altitudes prevented the satellites from leaving safe-mode to begin orbit raising maneuvers, and up to 40 of the satellites will reenter or already have reentered the Earth’s atmosphere. The deorbiting satellites pose zero collision risk with other satellites and by design demise upon atmospheric reentry—meaning no orbital debris is created and no satellite parts hit the ground. This unique situation demonstrates the great lengths the Starlink team has gone to ensure the system is on the leading edge of on-orbit debris mitigation.
On Tuesday, November 23 at 10:21 p.m. PST, Falcon 9 launched NASA’s Double Asteroid Redirection Test (DART) mission to an interplanetary transfer orbit from Space Launch Complex 4 East (SLC-4E) at Vandenberg Space Force Base in California. DART is humanity’s first planetary defense test mission to see if intentionally crashing a spacecraft into an asteroid is an effective way to change its course, should an Earth-threatening asteroid be discovered in the future. This was SpaceX’s first inter-planetary mission.
This was the third flight for this Falcon 9’s first stage booster, which previously supported launch of Sentinel-6 Michael Freilich and a Starlink mission.
On Thursday, November 11 at 6:32 p.m. EST, 23:32 UTC, SpaceX’s Dragon autonomously docked with the International Space Station. Falcon 9 launched the spacecraft to orbit from histsoric Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Center in Florida on Wednesday, November 10 at 9:03 p.m. EST.
On Thursday, November 11 at 6:32 p.m. EST, 23:32 UTC, SpaceX’s Dragon autonomously docked with the International Space Station. Falcon 9 launched the spacecraft to orbit from histsoric Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Center in Florida on Wednesday, November 10 at 9:03 p.m. EST.
After 199 days in space, the longest-duration mission for a U.S. spacecraft, Dragon and the Crew-2 astronauts, Shane Kimbrough , Megan McArthur , Akihiko Hoshide , and Thomas Pesquet , returned to Earth, splashing down off the coast of Pensacola, Florida at 10:33 p.m. EST on November 8.
Dragon and the Crew-2 astronauts were quickly recovered by the SpaceX recovery team. SpaceX will transport Dragon back to Cape Canaveral, Florida for inspections and refurbishment ahead of future human spaceflight missions.
This mission marked multiple firsts for SpaceX and NASA’s Commercial Crew Program, including being the first to fly two international partners, the first crew mission to use a flight-proven Dragon and Falcon 9, and the first U.S. spacecraft to spend 199 consecutive days in orbit.
After three days orbiting Earth, Dragon and the Inspiration4 crew – the world’s first civilian mission to orbit – safely splashed down off the coast of Florida at 7:06 p.m. EDT on Saturday, September 18, 2021, completing their first multi-day low Earth orbit mission.
Dragon performed a series of departure phasing burns to leave the circular orbit of 575 kilometers and then jettisoned its trunk ahead of its deorbit burn. After re-entering the Earth’s atmosphere, the spacecraft deployed its two drogue and four main parachutes in preparation for the soft water landing.
Inspiration4 is commanded by Jared Isaacman, founder and CEO of Shift4 Payments and an accomplished pilot and adventurer. Joining him are Medical Officer Hayley Arceneaux, a physician assistant at St. Jude Children’s Research Hospital® and pediatric cancer survivor; Mission Specialist Chris Sembroski, an Air Force veteran and aerospace data engineer; and Mission Pilot Dr. Sian Proctor, a geoscientist, entrepreneur, and trained pilot.
Developed by SpaceX to support NASA’s Commercial Crew Program, Dragon helped return human spaceflight capabilities in 2020 and has successfully flown three human spaceflight missions to the International Space Station (ISS) to-date. In addition to flying astronauts to space for NASA, Dragon can also carry commercial astronauts to Earth orbit, the ISS or beyond.
Today, Axiom Space announced SpaceX will fly three additional private crew missions aboard Dragon to and from the Station through 2023. Axiom previously announced their first mission to the International Space Station flying aboard Dragon, currently targeted to liftoff no earlier than January 2022. In May 2021, Axiom announced that astronaut Peggy Whitson and champion GT racer John Shoffner will serve as commander and pilot on the Ax-2 mission .
All four crews will receive combined commercial astronaut training from NASA and SpaceX, with SpaceX providing training on the Falcon 9 launch vehicle and Dragon spacecraft, emergency preparedness training, spacesuit and spacecraft ingress and egress exercises, as well as partial and full simulations.
The growing partnership between Axiom and SpaceX will enable more opportunities for more humans in space on the road to making humanity multiplanetary.
On Wednesday, May 5, Starship serial number 15 (SN15) successfully completed SpaceX’s fifth high-altitude flight test of a Starship prototype from Starbase in Texas.
Similar to previous high-altitude flight tests of Starship , SN15 was powered through ascent by three Raptor engines, each shutting down in sequence prior to the vehicle reaching apogee – approximately 10 km in altitude. SN15 performed a propellant transition to the internal header tanks, which hold landing propellant, before reorienting itself for reentry and a controlled aerodynamic descent.
The Starship prototype descended under active aerodynamic control, accomplished by independent movement of two forward and two aft flaps on the vehicle. All four flaps were actuated by an onboard flight computer to control Starship’s attitude during flight and enabled precise landing at the intended location. SN15’s Raptor engines reignited as the vehicle performed the landing flip maneuver immediately before touching down for a nominal landing on the pad.
These test flights of Starship are all about improving our understanding and development of a fully reusable transportation system designed to carry both crew and cargo on long-duration interplanetary flights, and help humanity return to the Moon, and travel to Mars and beyond.
Congratulations to the entire SpaceX team on SN15’s successful flight and landing!
After 167 days in space, the longest duration mission for a U.S. spacecraft since the final Skylab mission in 1974, Dragon and the Crew-1 astronauts, Mike Hopkins , Victor Glover , Shannon Walker , and Soichi Noguchi , returned to Earth on Sunday, May 2, 2021.
Dragon autonomously undocked from the International Space Station at 8:35 p.m. EDT on Saturday, May 1. The spacecraft performed a series of departure burns to move away from the orbiting laboratory. Before reentry, Dragon jettisoned its trunk to reduce weight and mass to help save propellant for the deorbit burn. The spacecraft then re-entered the Earth’s atmosphere and deployed its two drogue and four main parachutes in preparation for the soft water landing.
Approximately 6.5 hours after undocking, Dragon splashed down off the coast of Florida at 2:56 a.m. EDT on Sunday, May 2, completing the spacecraft’s first long-duration operational mission. This was also the first nighttime splashdown of a U.S. spacecraft with crew on board since Apollo 8’s return in 1968.
Upon splashdown, Dragon and the Crew-1 astronauts were quickly recovered by the SpaceX recovery team. SpaceX will transport Dragon back to Cape Canaveral for inspections and refurbishment ahead of future human spaceflight missions.
On Saturday, April 24 at 5:08 a.m. EDT, 9:08 UTC, SpaceX’s Dragon autonomously docked with the International Space Station (ISS) after Falcon 9 launched the spacecraft to orbit from historic Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Center in Florida on Friday, April 23 at 5:49 a.m. EDT, 9:49 UTC.
This is the first human spaceflight mission to fly astronauts on a flight-proven Falcon 9 and Dragon. The Falcon 9 first stage supporting this mission previously launched the Crew-1 mission in November 2020, and the Dragon spacecraft previously flew Robert Behnken and Douglas Hurley to and from the International Space Station during SpaceX’s Demo-2 mission in 2020.
As part of the Commercial Crew Program, NASA astronauts Shane Kimbrough and Megan McArthur , Japanese Aerospace Exploration Agency (JAXA) astronaut Akihiko Hoshide , and European Space Agency (ESA) astronaut Thomas Pesquet flew aboard the Dragon spacecraft on its second operational mission to the space station. This was the first time Dragon flew two international partners and also the first time two Crew Dragons are attached simultaneously to the orbiting laboratory.
After an approximate six-month stay, Dragon and the Crew-2 astronauts will depart from the space station no earlier than October 31 for return to Earth and splashdown in the Atlantic Ocean off the coast of Florida.
Only 24 humans have been to the Moon, and no one has been back since 1972. Today, NASA announced they have selected Starship to land the first astronauts on the lunar surface since the Apollo program. We are humbled to help NASA usher in a new era of human space exploration.
Together, NASA and SpaceX have successfully executed similarly bold and innovative partnerships, including restoring America’s ability to launch astronauts to orbit and return them safely home. We will build upon our shared accomplishments, and leverage years of close technical collaboration to return to the Moon. In doing so, we will lay the groundwork for human exploration to Mars and beyond.
Sustaining a human presence on the Moon will require the safe and affordable transportation of crew and significant amounts of cargo. SpaceX’s Starship spacecraft and Super Heavy rocket represent an integrated and fully reusable launch, propellant delivery, rendezvous, and planetary lander system with robust capabilities and safety features uniquely designed to deliver these essential building blocks.
Flying between lunar orbit and the surface of the Moon, Starship will carry crew and all of the supplies, equipment, and science payloads needed for extensive surface exploration. Building off the safety and reliability of Dragon and Falcon, Starship will feature proven avionics, guidance and navigation systems, autonomous rendezvous, docking and precision landing capabilities, as well as thermal protection, and a spacious cabin with familiar displays and interfaces utilized on Dragon .
SpaceX is rapidly advancing Starship development, drawing on an extensive history of launch vehicle and engine development programs. Since January 2020, SpaceX has built 10 Starship prototypes, with production and fidelity accelerating on each build. SpaceX has manufactured and tested more than 60 of Starship’s Raptor engines, accumulating nearly 30,000 seconds of total test time over 567 engine starts, including on multiple Starship static fires and flight tests. We have conducted six suborbital flight tests, including two 150-m hops and four high-altitude flights. SpaceX has also built a full-size Super Heavy booster as part of a pathfinder effort, and currently has five vehicles in production.
We are honored to be a part of NASA’s Artemis Program to safely land the first woman and next man on the surface of the Moon, as the first of many, many more people to follow.
On Tuesday, March 30, SpaceX launched its fourth high-altitude flight test of Starship from Starbase in Texas. Similar to previous high-altitude flight tests, Starship Serial Number 11 (SN11) was powered through ascent by three Raptor engines, each shutting down in sequence prior to the vehicle reaching apogee – approximately 10 km in altitude. SN11 performed a propellant transition to the internal header tanks, which hold landing propellant, before reorienting itself for reentry and a controlled aerodynamic descent.
Shortly after the landing burn started, SN11 experienced a rapid unscheduled disassembly. Teams will continue to review data and work toward our next flight test.
Test flights are all about improving our understanding and development of a fully reusable transportation system designed to carry both crew and cargo on long-duration interplanetary flights, and help humanity return to the Moon, and travel to Mars and beyond.
On Wednesday, March 3, Starship serial number (SN10) successfully completed SpaceX’s third high-altitude flight test of a Starship prototype from our site in Cameron County, Texas.
Similar to the high-altitude flight tests of Starship SN8 and SN9 , SN10 was powered through ascent by three Raptor engines, each shutting down in sequence prior to the vehicle reaching apogee – approximately 10 km in altitude. SN10 performed a propellant transition to the internal header tanks, which hold landing propellant, before reorienting itself for reentry and a controlled aerodynamic descent.
The Starship prototype descended under active aerodynamic control, accomplished by independent movement of two forward and two aft flaps on the vehicle. All four flaps were actuated by an onboard flight computer to control Starship’s attitude during flight and enabled a precise landing at the intended location. SN10’s Raptor engines reignited as the vehicle performed the landing flip maneuver immediately before successfully touching down on the landing pad!
As if the flight test was not exciting enough, SN10 experienced a rapid unscheduled disassembly shortly after landing. All in all a great day for the Starship teams – these test flights are all about improving our understanding and development of a fully reusable transportation system designed to carry both crew and cargo on long-duration interplanetary flights, and help humanity return to the Moon, and travel to Mars and beyond.
Congratulations to the entire Starship and SpaceX teams on the flight test!
In 2018, Japanese entrepreneur, Yusaku Maezawa, announced the world’s first private passenger mission to fly by the Moon aboard Starship . Known as dearMoon, this mission is an important step toward enabling access for people who dream of traveling to space. Today, the dearMoon project opened the application process for eight civilians to join Yusaku Maezawa on the week-long Starship mission around the Moon in 2023. Visit the dearMoon website or watch the video above to learn more on how to apply and potentially become a dearMoon crew member!
On Tuesday, February 2, Starship serial number 9 (SN9) completed SpaceX’s second high-altitude flight test of a Starship prototype from our site in Cameron County, Texas.
Similar to the high-altitude flight test of Starship serial number 8 (SN8) , SN9 was powered through ascent by three Raptor engines, each shutting down in sequence prior to the vehicle reaching apogee – approximately 10 kilometers in altitude. SN9 successfully performed a propellant transition to the internal header tanks, which hold landing propellant, before reorienting itself for reentry and a controlled aerodynamic descent.
The Starship prototype descended under active aerodynamic control, accomplished by independent movement of two forward and two aft flaps on the vehicle. All four flaps are actuated by an onboard flight computer to control Starship’s attitude during flight and enable precise landing at the intended location. During the landing flip maneuver, one of the Raptor engines did not relight and caused SN9 to land at high speed and experience a RUD.
These test flights are all about improving our understanding and development of a fully reusable transportation system designed to carry both crew and cargo on long-duration, interplanetary flights and help humanity return to the Moon, and travel to Mars and beyond.
In 2020, SpaceX returned America’s ability to fly NASA astronauts to and from the International Space Station for the first time since the Space Shuttle’s last flight in 2011. In addition to flying astronauts for NASA, Dragon was also designed to carry commercial astronauts to Earth orbit, the space station, or beyond.
Today, it was announced SpaceX is targeting no earlier than the fourth quarter of this year for Falcon 9’s launch of Inspiration4 – the world’s first all-commercial astronaut mission to orbit – from historic Launch Complex 39A at NASA’s Kennedy Space Center in Florida. Jared Isaacman, founder and CEO of Shift4 Payments, is donating the three seats alongside him aboard Dragon to individuals from the general public who will be announced in the weeks ahead. Learn more on how to potentially join this historic journey to space by visiting Inspiration4.com .
The Inspiration4 crew will receive commercial astronaut training by SpaceX on the Falcon 9 launch vehicle and Dragon spacecraft, orbital mechanics, operating in microgravity, zero gravity, and other forms of stress testing. They will go through emergency preparedness training, spacesuit and spacecraft ingress and egress exercises, as well as partial and full mission simulations.
This multi-day journey, orbiting Earth every 90 minutes along a customized flight path, will be carefully monitored at every step by SpaceX mission control. Upon conclusion of the mission, Dragon will reenter Earth’s atmosphere for a soft water landing off the coast of Florida.
On Wednesday, December 9, Starship serial number 8 (SN8) lifted off from our Cameron County launch pad and successfully ascended, transitioned propellant, and performed its landing flip maneuver with precise flap control to reach its landing point. Low pressure in the fuel header tank during the landing burn led to high touchdown velocity resulting in a hard (and exciting!) landing. Re-watch SN8's flight here.
Thank you to all the locals supporting our efforts in Cameron County and beyond. Congratulations to the entire Starship and SpaceX teams on today’s test! Serial number 9 (SN9) is up next – Mars, here we come!
On Monday, November 16 at 11:01 p.m. EST, 04:01 UTC on November 17, SpaceX’s Dragon autonomously docked with the International Space Station (ISS) after Falcon 9 launched the spacecraft to orbit from historic Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Center in Florida on Sunday, November 15, 2020.
As part of the Commercial Crew Program, NASA astronauts Mike Hopkins , Victor Glover , Shannon Walker , and JAXA astronaut Soichi Noguchi flew aboard Dragon on its first six-month operational mission to the space station. After its approximately six-month stay at the orbiting laboratory, Dragon and the astronauts will return to Earth and splashdown in the Atlantic Ocean off the coast of Florida.
Following Dragon’s second demonstration mission (Demo-2), NASA certified SpaceX for operational crew missions to and from the space station. Crew-1 is the first of three scheduled Dragon human spaceflights over the course of 2020 and 2021.
The return of human spaceflight to the United States with one of the safest, most advanced systems ever built is a turning point for America’s future space exploration, and it lays the groundwork for missions to the Moon, Mars, and beyond.
Today, NASA announced it has certified SpaceX’s Falcon 9 and Crew Dragon human spaceflight system for crew missions to and from the International Space Station – the first commercial system in history to achieve such designation. Not since the certification of the space shuttle nearly 40 years ago has NASA certified a spacecraft, rocket, and ground support systems for regular flights with astronauts.
Launched atop Falcon 9 on May 30, 2020, Dragon 's second demonstration flight test to and from the space station restored human spaceflight to the United States for the first time in almost a decade. That flight was the culmination of years of development, testing, and training—all throughout safety remained SpaceX’s top priority.
SpaceX put every component of every system through its paces, including two flight tests to and from the International Space Station, demonstrations of Dragon’s escape system both on the launch pad and in-flight, over 700 tests of the spacecraft's SuperDraco engines, more than 500 joint soft-capture docking tests to validate the performance of Dragon’s docking system design, about 8,000,000 hours of hardware in the loop software testing, and nearly 100 tests and flights of Dragon’s parachutes to ensure a safe landing back on Earth—in addition to all of the knowledge gained from twenty previous successful cargo resupply missions to the space station and over forty Falcon 9 block 5 launches.
SpaceX and NASA are targeting Saturday, November 14 at 7:49 p.m. EST for the launch of the first crew rotation mission (Crew-1) to the International Space Station as part of the agency’s Commercial Crew Program. The Crew-1 mission will launch NASA astronauts Michael Hopkins , Victor Glover , and Shannon Walker , along with Japan Aerospace Exploration Agency (JAXA) mission specialist Soichi Noguchi , from historic Launch Complex 39A at Kennedy Space Center in Florida.
Human spaceflight is SpaceX’s core mission, and we take seriously the responsibility that NASA has entrusted in us to safely carry astronauts to and from the International Space Station. We are humbled to help NASA usher in a new era of space exploration.
On Saturday, October 24 at 11:31 a.m. EDT, 11:31 UTC, SpaceX’s Falcon 9 rocket launched 60 Starlink satellites to orbit from Space Launch Complex 40 (SLC-40) at Cape Canaveral Air Force Station in Florida.
Falcon 9’s first stage previously supported the GPS III Space Vehicle 03 mission in June 2020 and a Starlink mission in September 2020. Following stage separation, SpaceX landed Falcon 9’s first stage on the “Just Read the Instructions” droneship, which was stationed in the Atlantic Ocean. The Starlink satellites deployed approximately 1 hour and 3 minutes after liftoff.
If you would like to receive updates on Starlink news and service availability in your area, please visit starlink.com .
This mission also marked the 100th successful flight of a Falcon rocket since Falcon 1 first flew to orbit in 2008.
SpaceX believes that fully and rapidly reusable rockets are the pivotal breakthrough needed to dramatically reduce the cost of access to space to enable people to travel to and live on other planets. While most rockets are expendable after launch — akin to throwing away an airplane after a one-way trip from Los Angeles to New York — SpaceX is working toward a future in which reusable rockets are the norm.
Of its now 100 successful flights of Falcon rockets, SpaceX has landed a Falcon first stage rocket booster 63 times and re-flown boosters 45 times. This year, SpaceX twice accomplished the sixth flight of an orbital rocket booster. And, in the ten years since its demonstration mission, Falcon 9 has become the most-flown operational rocket in the United States, overtaking expendable rockets that have been launching for decades.
The difficulty of precision landing an orbital rocket after it reenters Earth’s atmosphere at hypersonic velocity is not to be overlooked — SpaceX remains the only launch provider in the world capable of accomplishing this task. At 14 stories tall and traveling upwards of 1300 m/s (nearly 1 mi/s), stabilizing Falcon 9’s first stage booster for landing is like trying to balance a rubber broomstick on your hand in the middle of a hurricane. While recovery and re-flight of an orbital rocket booster may now seem routine, developing Falcon such that it would withstand reentry and return for landing was generally accepted as impossible — and SpaceX learned many lessons on the road to reusability .
SpaceX’s accomplishments with flight-proven rockets and spacecraft have allowed us to further advance the fleet’s reliability and reusability, as well as inform the development of Starship — SpaceX’s next-generation fully and rapidly reusable super heavy lift transportation system. Starship’s capability of full and rapid reuse will lower the cost of spaceflight to help humanity return to the Moon, travel to Mars, and ultimately become multi-planetary.
Ahead of Falcon 9’s upcoming launch of GPS III-4, the United States Space Force’s Space and Missile Systems Center (SMC) announced today an agreement with SpaceX to recover the first stage booster and, for the first time on a National Security Space Launch (NSSL) mission, launch previously flown boosters on future GPS missions. SpaceX is proud to leverage its flight-proven capabilities toward national security space launch missions.
SpaceX was also recently selected by the Space Force to carry out critical National Security Space Launch (NSSL) missions ordered over the next five years. SpaceX will build upon our years-long collaboration with the United States Air Force and the National Reconnaissance Office to utilize the operationally mature Falcon fleet, which has achieved NSSL certification and completed a combined 95 orbital missions to date for a variety of customers. With Falcon 9 and Falcon Heavy , SpaceX is capable of performing every type of national security space mission, to every required reference orbit, with significant performance and schedule margin.
To meet or exceed the demanding and unique requirements of the NSSL program, SpaceX invested over a billion dollars of its own money into the Falcon fleet and the associated ground infrastructure, manufacturing processes, payload integration procedures, and mission assurance processes. This private investment over multiple years reflects SpaceX’s deep commitment to reliably launching our customers' payloads to orbit. And, as SpaceX brought competition back to national security space launch, the United States Air Force saved billions in critical taxpayer funds.
SpaceX is honored to support the United States Space Force with a solution given the highest possible rating for system capability, schedule readiness, and system risk, using a mix of new and flight-proven launch vehicles. We look forward to leveraging this extensive capability to continue delivering the country’s most reliable and affordable launch services for years to come.
On Tuesday, August 4 at 4:56 p.m. CDT in Boca Chica, Texas, Starship serial number 5 (SN5) lifted-off from its launch mount and flew to a height of 150 meters before successfully touching down on a near-by landing pad.
On this flight test, SN5 was powered by a single Raptor engine – a reusable methalox full-flow staged-combustion rocket engine. This test flight was an important step in development of SpaceX’s fully reusable transportation system designed to carry both crew and cargo to Earth orbit, the Moon, Mars and beyond.
On Saturday, May 30, SpaceX’s Falcon 9 launched Crew Dragon’s second demonstration (Demo-2) mission from Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Center in Florida with NASA astronauts Bob Behnken and Doug Hurley aboard the spacecraft. Dragon autonomously docked to the International Space Station on Sunday, May 31, 2020.
Sixty-three days later, Crew Dragon undocked and departed from the orbiting laboratory, before successfully splashing down in the Gulf of Mexico off the coast of Pensacola, Florida on Sunday, August 2 at 2:48 p.m. EDT. This test flight marked the return of human spaceflight to the United States and the first-time in history a commercial company successfully took astronauts to orbit and back.
The Demo-2 mission was also the final major test milestone for SpaceX’s human spaceflight system to be certified by NASA for operational crew missions to and from the International Space Station. With the Demo-2 mission now complete, SpaceX and NASA teams are reviewing all the data for certification before NASA astronauts Victor Glover, Mike Hopkins, Shannon Walker, and JAXA astronaut Soichi Noguchi fly on Dragon’s first six-month operational mission (Crew-1), targeted for late September.
On Saturday, May 30 at 3:22 p.m. EDT, SpaceX’s Falcon 9 launched Crew Dragon’s second demonstration (Demo-2) mission from Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Center in Florida, and the next day Crew Dragon autonomously docked to the International Space Station. This test flight with NASA astronauts Bob Behnken and Doug Hurley on board the Dragon spacecraft returned human spaceflight to the United States.
Demo-2 is the final major test for SpaceX’s human spaceflight system to be certified by NASA for operational crew missions to and from the International Space Station. SpaceX is returning human spaceflight to the United States with one of the safest, most advanced systems ever built, and NASA’s Commercial Crew Program is a turning point for America’s future in space exploration that lays the groundwork for future missions to the Moon, Mars, and beyond.
SpaceX is launching Starlink to provide high-speed, low-latency broadband connectivity across the globe, including to locations where internet has traditionally been too expensive, unreliable, or entirely unavailable. We also firmly believe in the importance of a natural night sky for all of us to enjoy, which is why we have been working with leading astronomers around the world to better understand the specifics of their observations and engineering changes we can make to reduce satellite brightness. Our goals include:
Making the satellites generally invisible to the naked eye within a week of launch.
We're doing this by changing the way the satellites fly to their operational altitude, so that they fly with the satellite knife-edge to the Sun. We are working on implementing this as soon as possible for all satellites since it is a software change.
Minimizing Starlink's impact on astronomy by darkening satellites so they do not saturate observatory detectors.
We're accomplishing this by adding a deployable visor to the satellite to block sunlight from hitting the brightest parts of the spacecraft. The first unit is flying on the next launch, and by flight 9 in June all future Starlink satellites will have sun visors. Additionally, information about our satellites' orbits are located on space-track.org to facilitate observation scheduling for astronomers. We are interested in feedback on ways to improve the utility and timeliness of this information.
To better explain the details of brightness mitigation efforts, we need to explain more about how the Starlink satellites work.
Starlink Orbits
Starlink has three phases of flight: (1) orbit raise, (2) parking orbit (380 km above Earth), and (3) on-station (550 km above Earth). During orbit raise the satellites use their thrusters to raise altitude over the course of a few weeks. Some of the satellites go directly to station while others pause in the parking orbit to allow the satellites to precess to a different orbital plane. Once satellites are on-station they reconfigure so the antennas face Earth and the solar array goes vertical so that it can track the Sun to maximize power generation. As a result of this maneuver, the satellites become much darker because the solar array visibility from the ground is greatly reduced.
Currently, about half of the over 400 satellites are on-station and the other half are orbit raising or in the parking orbit. Satellites spend a small fraction of their lives orbit raising or parking and spend the vast majority of their lives on-station. It's important to note that at any given time, only about several hundred satellites will be orbit raising or parking. The rest of the satellites will be in the operational orbit on-station.
Starlink Satellite
The Starlink satellite design was driven by the fact that they fly at a very low altitude compared to other communications satellites. We do this to prioritize space traffic safety and to minimize the latency of the signal between the satellite and the users who are getting internet service from it. Because of the low altitude, drag is a major factor in the design. During orbit raise, the satellites must minimize their cross-sectional area relative to the 'wind,' otherwise drag will cause them to fall out of orbit. High drag is a double-edged sword—it means that flying the satellites is tricky, but it also means that any satellites that are experiencing problems will de-orbit quickly and safely burn up in the atmosphere. This reduces the amount of orbital debris or 'space junk' in orbit.
This low-drag and thrusting flight configuration resembles an open book, where the solar array is laid out flat in front of the vehicle. When Starlink satellites are orbit raising, they roll to a limited extent about the velocity vector for power generation, always keeping the cross sectional area minimized while keeping the antennas facing Earth enough to stay in contact with the ground stations.
When the satellites reach their operational orbit of 550 km, drag is still a factor—so any inoperable satellite will quickly decay—but the attitude control system is able to overcome this drag with the solar array raised above the satellite in a vertical orientation that we call 'shark-fin.' This is the orientation in which the satellite spends the majority of its operational life.
Satellite Visibility
Satellites are visible from the ground at sunrise or sunset. This happens because the satellites are illuminated by the Sun but people or telescopes on the ground are in the dark. These conditions only happen for a fraction of Starlink's 90-minute orbit.
This simple diagram highlights why satellites in orbit raise are so much brighter than the satellites that are on-station. During orbit raise, when the solar array is in open book, sunlight can reflect off of both the solar array and the body of the satellite and hit the ground. Once on-station, only certain parts of the chassis can reflect light to the ground.
Physics of Satellite Brightness
The apparent magnitude of an object is a measure of the brightness of a star or object observed from Earth. It is a reverse logarithmic scale, so higher numbers correspond to dimmer objects. A star of magnitude 3 is approximately 2.5 times brighter than a star of magnitude 4. Based on observations that have been taken by us and by members of the astronomical community, current Starlink satellites have an average apparent magnitude of 5.5 when on-station and brighter during orbit raise. Objects up to about magnitude 6.5-7 are visible to the naked eye (naked-eye visibility is closer to 4 in most suburbs), and our goal is for Starlink satellites to be magnitude 7 or better for almost all phases of their mission.
There are two types of reflections off of Starlink satellites: diffuse and specular. Diffuse reflections occur when light is scattered in many different directions. Imagine shining a flashlight at a white wall. Specular reflections happen when light is reflected in a particular direction. For example, the glint of sunlight off of a mirror. Diffuse reflections are the biggest contributor to observed brightness on the ground, because diffuse reflections go in all directions. You can see diffuse reflections as long as the satellite is visible. This is why Starlink satellites can create the 'string of pearls' effect in the night sky. It's a little counter-intuitive, but the shiny components of the Starlink satellites are a much smaller problem. Whether diffuse or specular, having a high reflectance helps the satellites stay cool in space. When sunlight hits a specular surface of the spacecraft and reflects, the vast majority of light reflects in the specular (mirror reflection) direction, which is generally out toward space (not toward Earth). Occasionally when it does, the glint only lasts for a second or less. In fact, specular surfaces tend to be the dimmest part of the satellite unless you are at just the right geometry.
The biggest contributors to Starlink being bright are the white diffuse phased array antennas on the bottom of the satellite, the white diffuse parabolic antennas on the sides (not shown below), and the white diffuse back side of the solar array. These surfaces are all white to keep temperatures down so components do not overheat. The key to making Starlink darker is to prevent sunlight from illuminating these white surfaces and scattering via reflection toward observers on the ground. While in orbit raise and the parking orbit the solar array dominates due to the much larger surface area. However, once the satellites are at their operational altitude, the antennas dominate because the bright backside of the solar array is shadowed.
Solutions In-Work
We've taken an experimental and iterative approach to reducing the brightness of the Starlink satellites. Orbital brightness is an extremely difficult problem to tackle analytically, so we've been hard at work on both ground and on-orbit testing.
For example, earlier this year we launched DarkSat, which is an experimental satellite where we darkened the phased array and parabolic antennas designed to tackle on-station brightness. This reduced the brightness of the satellite by about 55%, as was verified by differential optical measurements comparing DarkSat to other nearby Starlink satellites. This is nearly enough of a brightness reduction to make the satellite invisible to the naked eye while on-station. However, black surfaces in space get hot and reflect some light (including in the IR spectrum), so we are moving forward with a sun visor solution instead. This avoids thermal issues due to black paint, and is expected to be darker than DarkSat since it will block all light from reaching the white diffuse antennas.
Early Mission (Orbit Raise and Parking Orbit) Roll Maneuver
Since the visor is intended to help with brightness while on-station, it does not shade the back of the solar array, which means that it will not prevent orbit raise and parking orbit brightness. For this, we are working on changing the way the satellite flies up from insertion to parking orbit and to station.
We're currently testing rolling the satellite so the vector of the Sun is in-plane with the satellite body, i.e. so the satellite is knife-edge to the Sun. This would reduce the light reflected onto Earth by reducing the surface area that receives light. This is possible when orbit raising and parking in the precession orbit because we don't have to constrain the antennas to be nadir facing to provide coverage to internet users. However, there are a couple of nuanced reasons why this is tricky to implement. First, rolling the solar array away from the Sun reduces the amount of power available to the satellite. Second, because the antennas will sometimes be rolled away from the ground, contact time with the satellites will be reduced. Third, the star tracker cameras are located on the sides of the chassis (the only place they can go and have adequate field of view). Rolling knife edge to the Sun can point one star tracker directly at the Earth and the other one directly at the Sun, which would cause the satellite to have degraded attitude knowledge.
There will be a small percentage of instances when the satellites cannot roll all the way to true knife edge to the Sun due to one of the aforementioned constraints. This could result in the occasional set of Starlink satellites in the orbit raise of flight that are temporarily visible for one part of an orbit.
On-Station Brightness
Satellites spend most of their lives on-station, where they will always be in the shark-fin configuration during visible passes. We can adjust the solar array positioning in this configuration to reflect light from its largely specular solar cells away from Earth and to partially hide it behind the chassis. The main remaining goal is to block the phased arrays and antennae from direct view of the sun. The goal is to cover the white phased array antennas and the parabolic antennas on the sides of the satellite.
Using our low orbital altitude and flat satellite geometry to our advantage, we designed an RF-transparent deployable visor for the satellite that blocks the light from reaching most of the satellite body and all of the diffuse parts of the main body. This visor lays flat on the chassis during launch and deploys during satellite separation from Falcon 9. The visor prevents light from reflecting off of the diffuse antennas by blocking the light from reaching the antennas altogether. Not only does this approach avoid the thermal impacts from surface darkening the antennas, but it should also have a larger impact on brightness reduction. As previously noted, the first VisorSat prototype will launch in May and we will have these black, specular visors on all satellites by June. The parabolic antennas on the sides of the Starlink satellite also have visor-like coverings that darken them.
We have been working with leading astronomical groups in this effort—in particular the American Astronomical Society and the Vera C. Rubin Observatory—to better understand the methods and instruments employed by the astronomy community. With AAS, we have increased our understanding of the community as a whole through regular calls with a working group of astronomers during which we discuss technical details, provide updates, and work on how we can protect astronomical observations moving forward. A post on some of our sessions is here . One particularly useful presentation from a member of this working group is here .
While community understanding is critical to this problem, engineering problems are difficult to solve without specifics. The Vera C. Rubin Observatory was repeatedly flagged as the most difficult case to solve, so we've spent the last few months working very closely with a technical team there to do just that. Among other useful thoughts and discussions, the Vera Rubin team has provided a target brightness reduction that we are using to guide our engineering efforts as we iterate on brightness solutions.
These technical and community discussions are paired with our existing efforts to make the satellites easier for astronomers to avoid. Starlink trajectories are published through space-track.org and celestrak.com , which many astronomers use in timing their observations to avoid satellite streaks. We've also started publishing predictive data prior to launch at the request of astronomers. These allow observatories to schedule around the satellites in the first few hours of deployment (as satellites de-tumble and enter the network).
Vera Rubin has been described as the limiting case for Starlink, due to its enormous aperture and wide field of view. These two characteristics work in concert to produce the perfect storm for satellite observations. Most astronomical systems look at an extremely small section of the sky (less than 1 degree), which makes it exceedingly unlikely that a satellite will cross in front of the imaging system in a given observation. On the other hand, systems with very large fields of view normally aren't extremely sensitive, meaning that, while streaks will occur, they will have a small impact on the overall data collection. This is why we've been working so closely with the team at the Rubin Observatory. In fact, despite its wide field of view, the Vera C. Rubin Observatory is sensitive enough to detect a sunlit golf ball as far away as the Moon.
So what can we do to mitigate our impact on these edge cases of wide, fast survey telescopes?
Minimizing the Impact on Astronomy
The huge collecting area of a larger telescopes like Vera C. Rubin Observatory leads to a sensitivity that will render even the darkest satellites visible.They are so sensitive that it won't be possible to build a satellite that will not produce streaks, in a typical long integration. There is much that can be done to reduce the impact of satellite streaks, and that starts with an understanding of how astronomical sensors work.
The astronomical community has done a great job of educating us on their imaging techniques. Optical systems use mirrors or lenses to focus light onto an imaging sensor. Most optical astronomy instruments use sensors called charge-coupled-devices (CCDs) as their detectors because astronomical targets, such as distant supernovae and galaxies, are generally dim–at the limit of what can be detected by a sensor. For these applications, the lower noise level of CCDs allows for a higher signal-to-noise ratio for a given image, making it easier to see very faint features in the universe.
However, CCDs suffer from a key drawback: when compared to other common sensors, like the CMOS sensor in your cell phone. If you point your cell phone at a bright light, you'll see all the pixels saturate and turn white in the region of the bright source. If you look at the same target with an optical system that uses a CCD sensor, you'll notice that this bright spot extends to create vertical stripes on the image.
This difference is due to the way each sensor type reads the values for each pixel. While a CMOS sensor essentially has an amplifier at each pixel that turns the light collected into a digital value, a CCD sensor has a limited number of amplifiers and moves the collected light (in the form of electrons) across the sensor, to be digitized. This mechanism means that a saturated pixel on a CCD tends to wipe out data from an entire column of pixels.
This effect, commonly referred to as 'blooming,' is one example of how a very small but bright source of light can impact an astronomical observation. This principle is the core of our mitigation efforts. While it will not be possible to create satellites that are invisible to the most advanced optical equipment on Earth, by reducing the brightness of the satellites, we can make the existing strategies for dealing with similar issues, such as frame-stacking, dramatically more effective.
Future Satellites
SpaceX is committed to making future satellite designs as dark as possible. The next generation satellite, designed to take advantage of Starship's unique launch capabilities, will be specifically designed to minimize brightness while also increasing the number of consumers that it can serve with high-speed internet access.
While SpaceX is the first large constellation manufacturer and operator to address satellite brightness, we won't be the last. As launch costs continue to drop, more constellations will emerge and they too will need to ensure that the optical properties of their satellites don't create problems for observers on the ground. This is why we are working to make this problem easier for everyone to solve in the future.
SpaceX and NASA are targeting May 27 for Falcon 9’s launch of Crew Dragon’s second demonstration mission (Demo-2) from historic Launch Complex 39A at NASA’s Kennedy Space Center in Florida as part of NASA’s Commercial Crew Program . NASA astronauts Bob Behnken and Doug Hurley will be the first two NASA astronauts to fly onboard the Dragon spacecraft as part of the Demo-2 mission to and from the International Space Station, which will return human spaceflight to the United States since the Space Shuttle was retired in 2011.
Filled with approximately 4,500 pounds of supplies and payloads, Dragon launched aboard a Falcon 9 rocket on March 6, 2020 from Cape Canaveral Air Force Station in Florida. The Dragon spacecraft that supported the CRS-20 mission previously supported the CRS-10 mission in February 2017 and the CRS-16 mission in December 2018. Dragon is the only spacecraft currently flying that's capable of returning significant amounts of cargo to Earth.
The Falcon 9 launch vehicle and Crew Dragon spacecraft that will support Demo-2 are onsite at SpaceX’s facilities in Florida. To mark the return of human spaceflight on American rockets from American soil, NASA has revived their worm logo for Demo-2 .
In preparation for Demo-2, SpaceX has completed a number of major milestones for NASA’s Commercial Crew Program. In March 2019, SpaceX completed an end-to-end test flight of Crew Dragon without NASA astronauts onboard, making Dragon the first American spacecraft to autonomously dock with the International Space Station and safely return to Earth.
In January 2020, SpaceX demonstrated Crew Dragon's in-flight launch escape capability to reliably carry crew to safety in the unlikely event of an emergency on the launch pad or at any point during ascent. SpaceX has completed over 700 tests of the spacecraft's SuperDraco engines, which fired together at full throttle can power Dragon 0.5 miles away from Falcon 9 in 7.5 seconds, accelerating the vehicle more than 400 mph.
SpaceX has completed 27 tests of Crew Dragon’s enhanced Mark 3 parachute design, which will provide a safe landing back on Earth for astronauts returning from the Space Station. These tests include 13 successful single parachute drop tests, 12 successful multi-parachute tests, and a successful demonstration of the upgraded parachute system during Crew Dragon’s in-flight abort test .
Additionally, SpaceX and NASA have jointly executed a series of mission simulations from launch and docking to departure and landing, an end-to-end demonstration of pad rescue operations , and a fully integrated test of critical crew flight hardware on the Demo-2 Crew Dragon spacecraft with NASA astronauts Bob Behnken and Doug Hurley participating in their Demo-2 spacesuits.
Demo-2 is the final major test for SpaceX’s human spaceflight system to be certified by NASA for operational crew missions to and from the International Space Station. Once Demo-2 is complete, and the SpaceX and NASA teams have reviewed all the data for certification, NASA astronauts Victor Glover , Mike Hopkins , Shannon Walker and JAXA astronaut Soichi Noguchi have been assigned to fly on Dragon’s first six-month operational mission (Crew-1) targeted for later this year.
SpaceX is returning human spaceflight to the United States with one of the safest, most advanced systems ever built, and NASA’s Commercial Crew Program is a turning point for America’s future in space exploration that lays the groundwork for future missions to the Moon, Mars, and beyond.
On Sunday, January 19, SpaceX successfully completed an in-flight test of Crew Dragon’s launch escape capabilities from Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Center in Florida. This test, which did not have NASA astronauts onboard the spacecraft, demonstrated Crew Dragon’s ability to reliably carry crew to safety in the unlikely event of an emergency on ascent. Falcon 9 and Dragon lifted off at 10:30 a.m. EST, or 15:30 UTC, with the abort sequence initiating approximately one and a half minutes into flight.
Crew Dragon's eight SuperDraco engines powered the spacecraft away from Falcon 9 at speeds of over 400 mph. Following separation, Dragon's trunk was released and the spacecraft's parachutes were deployed, first the two drogue parachutes followed by the four upgraded Mark III parachutes. Dragon safely splashed down in the Atlantic Ocean and teams successfully recovered the spacecraft onto SpaceX's recovery vessel. You can watch a replay of launch above and learn more about the mission here .
SpaceX's Starship and Super Heavy launch vehicle is a fully, rapidly reusable transportation system designed to carry both crew and cargo to Earth orbit, the Moon, Mars, and anywhere else in the solar system. On Saturday, September 28 at our launch facility in Cameron County, Texas, SpaceX Chief Engineer Elon Musk provided an update on the design and development of Starship.