Human exploration of Mars is now an official goal of the National Aeronautics and Space Administration (NASA).

　　Last month, U.S. President Donald Trump signed a bill to increase NASA's budget. The law sets spending at $19.5 billion for the 12-month period starting on October 1, 2017. Congress will need to approve the money.

　　And for the first time, the NASA budget adds human exploration of Mars as an official goal for the agency.

　　The president spoke at the signing ceremony. Trump said he was happy to sign the spending plan into law. He added that for almost 60 years NASA has inspired millions of Americans to imagine distant worlds and a better future on earth.

　　"It's been a long time since a bill like this has been signed, reaffirming our national commitment to the core mission of NASA: human space exploration, space science and technology."

　　Working with private companies

　　Sending astronauts to Mars is the next great test for NASA. Space agency officials hope to have people on Mars by the 2030s. The agency is expected to develop new technology to carry out the mission by working with private companies.

　　SpaceX, owned by businessman Elon Musk, is working on its own plan to get to Mars. His company plans to launch an unmanned spaceship to the red planet as soon as 2018.

　　When sending anyone into deep space, one of the biggest problems is how to deal with damaging radiation. The spacecraft has to be built with materials that protect against the effects of radiation. But more work is needed.

　　Working to protect against radiation

　　Scientists are working on ways to protect astronauts from the radiation they will face while traveling outside Earth's atmosphere. The atmosphere and Earth's magnetic fields protect us from the damaging and possibly deadly effects of cosmic and gamma rays from our sun and outer space. High levels of radiation can lead to cancer and sometimes death.

　　If there were a nuclear disaster here on Earth, it would take several meters of lead or thick concrete to keep us safe from the radiation.

　　The same is true for astronauts in space.

　　The thin atmospheres of the moon and Mars will not provide protection for the people who might travel or live there. So shielding human beings from radiation is a critical part of colonizing space.

　　Scientists are working on several methods of protection.

　　Radiation vest

　　One involves a vest to be worn by astronauts. Called the AstroRad Radiation Shield, it is a product of an Israeli company called StemRad.

　　Gideon Waterman is StemRad's chief technology officer.

　　"From the worst case of a nuclear disaster, to the best case of humans walking on Mars, we're providing the best possible radiation protection."

　　The vest is designed to protect vital human tissue, like reproductive organs and lungs, from radiation. It will also protect stem cells. These are simple cells in the body that are able to develop into different kinds of cells, such as blood cells, cells for making skin or other body parts.

　　The vest may get its first test in space in 2018. It may travel into space when NASA's Orion spacecraft makes its first test trip around the moon. StemRad says it will provide the same protection as a shielded "safe room" traveling on the Orion.

　　Oren Milstein is the company's CEO and Chief Scientific Officer.

　　"Based on our simulations we're sure it works, but, you know, to be one hundred percent sure, we're sending this up EM-1 (Exploration Mission 1) which is NASA's next launch of the Orion space capsule."

　　The vest is lightweight. It is made of many small cells. These cells are grouped together, so the device looks almost like a honeycomb made by a bee. Every vest will be made individually for each astronaut.

　　NASA options under development

　　NASA is also exploring other ways for dealing with the radiation. One idea is building a storm shelter deep inside the floor of the Orion spacecraft. Astronauts would hide there in the event of a solar flare storm. Solar flares are sudden bursts of energy from a small area of the sun's surface.

　　The space agency is also working on developing drugs, like anti-oxidants, to fight the effects of radiation. This medicine could be taken to reverse some of the effects of severe radiation exposure from solar flares.

　　I'm Anne Ball.

　　Anne Ball wrote this story for Learning English based on VOA news reports and additional material. George Grow was the editor.

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