In order to generate enough lift to take off by flapping their arms, a person would have to flap their arms at an incredibly high speed. The exact speed would depend on various factors such as the person's weight, wing span, and the air density. However, it is estimated that a person would have to flap their arms at a speed of around 15-20 flaps per second, which is much faster than what a human is capable of achieving. This is due to the fact that the human body is not designed for flight in the same way that birds or insects are. **

The defining moments of space exploration include the launch of the first artificial satellite, Sputnik 1, by the Soviet Union in 1957, which marked the beginning of the space age. The Apollo 11 mission in 1969, when humans first set foot on the moon, was another defining moment that captured the world's imagination. The launch of the Hubble Space Telescope in 1990 allowed us to see deep into the universe and revolutionized our understanding of space. More recently, the successful landing of the Mars rover Perseverance in 2021 has opened up new possibilities for exploring the red planet. **

No, Russia's space exploration is not at an end. While Russia has faced some challenges in its space program, such as budget constraints and technical issues, it continues to be an active player in space exploration. Russia has a long history of achievements in space, including being the first country to launch a satellite and send a human into space. The country is also involved in international collaborations, such as the International Space Station, and has plans for future missions to the moon and Mars. Therefore, Russia's space exploration is far from over. **

I'm sorry, but I am an AI and do not have the ability to physically see or interact with objects. If you could provide more context or details about the bracket flap, I may be able to help you in a different way. **

The cat flap is secure because it is designed to only allow access to the cat wearing a specific collar with a corresponding sensor. This means that other animals or intruders cannot enter the house through the cat flap. Additionally, the cat flap is made of durable materials and is securely installed in the door, making it difficult for anyone to tamper with or force their way through. Overall, the cat flap provides a secure and convenient way for the cat to enter and exit the house. **

One popular PC game about space exploration is "Elite Dangerous." In this game, players can explore a realistic 1:1 scale open-world galaxy, trade goods, mine resources, engage in combat, and more. The game offers a vast and immersive experience for players interested in space exploration and simulation. "Elite Dangerous" has received positive reviews for its attention to detail and expansive gameplay options. **

Space probes are sent on exploration missions using powerful rockets that launch them into space. These rockets provide the necessary thrust to escape Earth's gravity and propel the probe towards its destination. Once in space, the probe's trajectory is carefully calculated to ensure it reaches its target planet or celestial body. The probe is equipped with various instruments and communication systems to collect data and send it back to Earth. **

Manned space exploration allows for human presence and decision-making in space, enabling more complex and flexible missions. Astronauts can conduct experiments, repair equipment, and make real-time decisions that may be challenging for robots. However, manned missions are significantly more expensive and risky compared to robotic missions. Astronauts face health risks, such as exposure to radiation and microgravity effects, and the cost of ensuring their safety adds to the overall expense of manned space exploration. **