According to foreign media reports,Last weekend, NASA announced its choice to award a contract worth US$178 million to SpaceX to launch an observation satellite to Jupiter’s icy satellite Europa.The satellite is called Europa Clipper and was originally scheduled to be launched by Boeing’s Space Launch System (SLS) launch vehicle, which was developed specifically for NASA. However, due to schedule constraints, the space agency had new ideas for the use of SLS as early as last year. At that time, it believed that switching to commercial vehicles would save up to $1.5 billion in launch and other costs for the Europa Clipper mission.
SpaceX will use its Falcon Heavy rocket to launch the Europa Clipper mission in October 2024. NASA requires that the rocket selected for the Clipper mission be capable of transporting more than 6 tons of payload (Clipper weighs 6065 kg) in Mars-Earth Gravity Assist (MEGA) orbit. MEGA will provide Clipper with some momentum, as it will take a six-year journey to the moon of Jupiter.
NASA’s initial estimates for this mission indicate that Clipper will have to perform no less than four gravity-assisted orbit changes during this period. This will involve Earth, Mars and Venus once each, and will provide Clipper with the necessary energy to reach Europa, which is 628 million kilometers away from Earth.
However, during this mission, it seems that the most risky flyby of Venus may be cancelled. Although NASA did not mention Venus in the press release or its proposal requirements, the 48BV start-up stage of the orbiting ATK company may help the Falcon Heavy rocket to avoid Venus’s gravity-assisted orbit change. Due to the high radiation level of the inner solar system, the auxiliary orbit change is dangerous, which requires shielding the spacecraft and increasing its launch mass.
The longer duration of the Falcon Heavy is due to the rocket’s thrust. SpaceX’s heavy rocket can generate 5 million pounds of thrust when it lifts off. In contrast, the SLS, which is classified as a super-heavy launch vehicle, can generate 8.4 million pounds of thrust when it lifts off. Since the United Launch Alliance cannot purchase engines for its rockets, these two launch vehicles are the only launch vehicles NASA can consider for the Clipper mission.
Using a commercial launch vendor (now confirmed to be SpaceX) allows NASA to save up to $1.5 billion in launch costs, which the space agency outlined to Congress early last year. These savings come not only from the reusability of the Falcon Heavy rocket-SpaceX’s rocket reuses all of its first stages-but also due to reduced storage costs.
SLS is the main force of NASA’s “Artemis” program, and its scheduling restrictions make the availability of the Clipper rocket’s launch date uncertain, although the spacecraft is expected to be ready for flight in 2023. The longer the delay of the SLS rocket, the higher the storage cost of NASA, which is just the tip of the iceberg. This is because if the space agency locks the SLS for the mission and the rocket is unusable, it will have to pay for the cost of building a new rocket from scratch.
As for SpaceX, the company plans to replace the Falcon 9 and Falcon Heavy rockets with its Starship next-generation launch vehicle system. Starship aims to generate more than 16 million pounds of thrust and forms the core of the company’s interstellar mission plans, including missions to the surface of Mars.
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