The Falcon Heavy rocket is SpaceX’s most powerful launch vehicle, featuring 27 Merlin engines (nine per booster) and generating 5.13 million pounds of thrust at liftoff. The rocket consists of three Falcon 9 first-stage cores designed for reusability, reducing costs significantly by recovering and reusing the side boosters. Falcon Heavy can lift 64 metric tons (141,000 pounds) to low Earth orbit (LEO) and approximately 26.7 tons to geostationary transfer orbit (GTO).

Some key advancements include:

- Reuse of boosters: The rocket’s side boosters land back on Earth, ready for reuse, significantly reducing costs.

- Payload capacity: It can carry large payloads, making it ideal for launching large satellites, space probes, and crewed spacecraft for potential deep space missions.

- Flexibility: Falcon Heavy can send payloads to the Moon, Mars, and beyond, making it essential for NASA’s plans for deep space exploration and commercial missions.

 Significant Milestones:

1. Maiden Flight (February 6, 2018): The first flight of the Falcon Heavy launched Elon Musk’s Tesla Roadster into a heliocentric orbit, demonstrating the rocket's capabilities.

2. U.S. Air Force STP-2 Mission (2019): A critical demonstration of Falcon Heavy's ability to perform complex missions, delivering multiple payloads to various orbits.

3. NASA’s Artemis Program: Falcon Heavy has been selected for missions supporting NASA's Moon exploration efforts, such as the Psyche mission and Gateway station logistics.

The computing power of the Mercury spacecraft compared to a modern iPhone is starkly different, highlighting the vast technological advancements over the past decades.

Mercury Spacecraft (1959-1963):

- The Mercury spacecraft's computing capabilities were minimal. The onboard systems were primarily mechanical and analogue, with minimal digital computation. Most calculations were done on the ground, and communication with the spacecraft was handled through radio telemetry.

- The only real "computer" involved was the ground-based IBM 701 or 7090, which handled data processing and flight simulation.

- The onboard systems mainly relied on simple transistor-based electronics for control and navigation, with computation power measured in just a few thousand instructions per second (KIPS).

Modern iPhone (e.g., iPhone 14 Pro):

- A modern iPhone has a multi-core processor with billions of transistors and can perform up to trillions of operations per second (teraflops). For instance, the A16 Bionic chip can handle up to 15.8 trillion operations per second.

- The iPhone also includes advanced graphics processing units (GPUs), neural engines for AI and machine learning tasks, and substantial amounts of RAM and storage.

Comparison:

The Mercury spacecraft's computing power is dwarfed by that of a modern iPhone, which is millions of times more powerful in terms of computational capability.

- To put it in perspective, the iPhone in your pocket has more computing power than all of NASA's computers combined at the time of the Apollo moon landings, let alone the Mercury missions.

- The iPhone can perform complex computations, support high-resolution graphics, and manage extensive communication and data processing tasks that would have been unimaginable with the technology available during the Mercury program.

In essence, the Mercury spacecraft had the equivalent of almost no digital computing power compared to the highly advanced and capable iPhone of today.