So the astronauts at the Orion spacecraft are currently further away from Earth than any other human ever. It *is* amazing that this happens in 2026, when essentially everything else in the world goes to hell.
But note also the following: the furthest away humans have been from Earth is a flyby around the Moon. You know, Earth´s satellite - which is fully visible from the Earth´s surface essentially every day.
That´s it. So perhaps not the right time for any high falutin´ cornucopian fantasies about our destiny being in the stars (or a manned mission to Mars)...
Didn't it come out that a manned mission to land on Mars would not return, even if they did indeed land successfully?
ReplyDeleteGemini thinks it ´s possible to return, but very difficult!
ReplyDeleteCould a manned mission to Mars ever come back to Earth, even if it reaches Mars?
The short answer is yes, but it is exponentially more difficult than the one-way trip. To understand why, you have to look at the "tyranny of the rocket equation": to get off Earth, you need fuel. To get off Mars, you need more fuel. But to have that fuel on Mars, you have to carry it all the way from Earth, which requires even more fuel to lift it in the first place.
NASA and private companies like SpaceX plan to solve this using a strategy called In-Situ Resource Utilization (ISRU)—essentially "living off the land."
1. The "Gas Station" on Mars
Bringing enough fuel from Earth for a return trip is currently weight-prohibitive. Instead, the plan is to manufacture fuel on the Martian surface.
The Sabatier Reaction: Mars has an atmosphere that is 95% Carbon Dioxide (CO2 ). By bringing a small amount of Hydrogen (H) from Earth (or extracting it from Martian ice), astronauts can use a chemical reactor to create Methane (CH4) and Oxygen (O2).
Propellant: This combination (Methalox) is exactly what engines like SpaceX’s Raptor use.
The Timeline: A robotic "fuel factory" would likely be sent to Mars years before the humans arrive to ensure the "tank is full" before they even leave Earth.
2. The Launch from Mars
Mars has about 38% of Earth's gravity. While this makes it easier to launch than from Earth, it is still a massive undertaking.
No Launchpad: On Earth, we have massive towers, cooling systems, and technicians. On Mars, the Starship (or Ascent Vehicle) must act as its own launchpad, landing vertically and then taking off again from the dusty ground.
Ascent: The ship must reach "Mars Escape Velocity" (approx. 5 km/s) to enter orbit and begin the journey home.
3. The "Waiting Room" (Orbital Mechanics)
You can’t just leave Mars whenever you want. Because Earth and Mars move at different speeds around the Sun, they only align favorably every 26 months.
The Stay: Astronauts would likely have to stay on the surface for about 500 days waiting for the "Return Window."
The Transit: Once the window opens, the trip back takes another 6 to 9 months.
4. The Return Entry: The Hardest Part
Returning to Earth is actually more dangerous than landing on Mars.
Velocity: A ship returning from Mars hits Earth’s atmosphere at roughly 11 to 14 km/s (approx. 25,000–31,000 mph). This is much faster than a return from the International Space Station.
Heat: The heat shield must withstand temperatures that can vaporize metal. The ship must hit a tiny "entry corridor"—too steep and they burn up; too shallow and they "skip" off the atmosphere back into deep space.
Has it been tested?
We have already proven the concept! In 2021, NASA’s MOXIE instrument on the Perseverance rover successfully sucked in Martian air and produced breathable oxygen. The next step is scaling that up to produce the tons of liquid oxygen needed to lift a rocket back into space.
The verdict: We have the physics and the chemistry figured out. The only remaining hurdles are the engineering of scale and the funding to build a ship that can survive the harshest round-trip in human history.
Gemini forgot to factor in that humans might not be psychologically or physically fit for "the harshest round-trip in human history". Computers, eh?
ReplyDeleteTry travelling at 31,000 mph ! And skidding to a near halt when approaching Earth's atmosphere. And yes, 500 days on an alien planet? Sounds like a movie script.
ReplyDelete