内容摘要：The Durham native announced earlier this year she had been diagnosed with cancer after previously

The Durham native announced earlier this year she had been diagnosed with cancer after previously

The tyres need to be able to deform as they go over rocks and then ping back to their original shape."If we permanently deform a tyre, it doesn't roll efficiently, and we have issues with power loss," says Dr Padula.

The new wheels will also carry much bigger loads than the lightweight rovers Apollo astronauts cruised around in.The next space missions will need to drive round "bigger science platforms and mobile habitats that get larger and larger", he says.And that will be an even heftier problem on Mars, where gravity is double that on the Moon.

Apollo's lunar rovers used tyres made from zinc-coated piano wire in a woven mesh, with a range of around 21 miles.Since extreme temperatures and cosmic rays break down rubber or turn it to a brittle glass, metal alloys and high-performance plastic are chief contenders for airless space tyres.

"In general, metallic or carbon fibre-based materials are used for these wheels," says Pietro Baglion, team leader of the European Space Agency's (ESA) Rosalind Franklin Mission, which aims to send its own rover to Mars by 2028.

One promising material is nitinol, an alloy of nickel and titanium.The BBC has contacted CoreCivic for comment, but has not received a reply.

"So far, that form is the only government document linking Mr Hernández to the Tren de Aragua," Lindsay Toczylowski, executive director of the Immigrant Defenders Law Centre and part of the legal team representing the young Venezuelan, told BBC Mundo.Authorities have not provided further information about Mr Hernández's case, or the charges faced by him or other Venezuelans recently deported to El Salvador.

Lawyers defending migrants' cases do not know whether the particular score system that marked Mr Hernández as a suspected member of Tren de Aragua has been used during the assessment of other detainees. However, authorities have acknowledged that tattoos are one of the criteria used for identifying gang members.According to court documents filed by the American Civil Liberties Union (ACLU) on behalf of Venezuelan deportees, there is second scoring guide which evaluates detainees on a 20-point scale.