SpaceX Reveals Details of $843 Million Dragon Capsule for ISS Deorbit
SpaceX has unveiled plans for an $843 million spacecraft called the U.S. Deorbit Vehicle (USDV) that will be used to bring down the International Space Station (ISS) at the end of the decade. The USDV will be a modified version of SpaceX’s Dragon capsule, which is currently used to transport astronauts and cargo to orbit. The design of the USDV incorporates flight-proven hardware, which played a significant role in NASA’s decision to award the contract to SpaceX over Northrop Grumman, the only other bidder. The use of flight heritage is crucial for reliability, as stated by Dana Weigel, NASA’s ISS program manager.
The purpose of the USDV is to execute a series of critical burns that will occur during the last week of the station’s life. However, the spacecraft will be launched approximately 18 months before these burns take place and will dock to the forward port of the ISS. NASA plans to leave crew members onboard as long as possible to maintain the station’s trajectory, but they will eventually depart around six months before reentry.
Once the station reaches an altitude of about 220 kilometers above Earth, the USDV will perform a series of burns over a period of four days to set up a precise deorbit trajectory. It will then conduct the final reentry burn, and any remaining parts that survive the Earth’s atmosphere will land in an uninhabited ocean. This disposal method is consistent with previous large spacecraft, such as Northrop Grumman’s Cygnus and Japan’s HTV cargo capsule.
Developing the USDV presents several challenges for SpaceX, including the need to create a powerful enough vehicle to guide the station through increasing atmospheric drag. Sarah Walker, SpaceX’s director of Dragon mission management, emphasized the complexity of the final burn, which must be powerful enough to fly the entire space station while resisting torques and forces caused by atmospheric drag.
To achieve this, SpaceX’s design for the USDV includes six times more usable propellant, three to four times more power generation and storage, and an increased number of Draco thrusters. The spacecraft will feature a trunk attached to its end, which will house the additional propellant, power generation, and avionics required for the mission. The goal is to minimize the debris footprint, although some debris is expected, ranging in size from microwave ovens to small sedans.
The decision to seek a deorbit vehicle from private industry was made jointly by NASA and other station partners, including Roscosmos, the European Space Agency, the Japan Aerospace Exploration Agency, and the Canadian Space Agency. This collaboration came after realizing that Roscosmos-provided capabilities were insufficient for the size of the station. The contract with SpaceX differs from previous agreements, as NASA will be responsible for procuring the launch and operation of the spacecraft, as well as bringing the ISS back to Earth.
NASA plans to procure a rocket approximately three years before launch and operate the spacecraft for the deorbit mission. The agency anticipates that the ISS will cease operations in 2030, with splashdown occurring the following year. To ensure a smooth transition, NASA aims to overlap with commercial space station providers in low Earth orbit. However, variables such as development schedules of commercial companies like Axiom Space, Voyager Space-led Starlab, and the Blue Origin and Sierra Space venture Orbital Reef could impact this transition. NASA associate administrator Ken Bowersox explained that beyond 2030, continued operation of the station would require approval from the government and cooperation with partner space agencies.
In summary, SpaceX’s USDV presents an innovative solution for safely bringing down the ISS at the end of its lifespan. NASA’s emphasis on flight heritage and reliability led to the selection of SpaceX’s design over its competitor. The complex mission requires a powerful vehicle capable of navigating increasing atmospheric drag, which SpaceX has achieved through significant enhancements to the Dragon capsule’s propellant, power generation, and thrusters. The collaboration between NASA and private industry reflects the growing role of commercial space exploration, and efforts will be made to ensure a seamless transition to commercial space station providers in the future.